[JFFS2][XATTR] Remove 'struct list_head ilist' from jffs2_inode_cache.
[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         if (jffs2_sum_active() && s)
226                 kfree(s);
227
228         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
229         if (c->nextblock && (c->nextblock->dirty_size)) {
230                 c->nextblock->wasted_size += c->nextblock->dirty_size;
231                 c->wasted_size += c->nextblock->dirty_size;
232                 c->dirty_size -= c->nextblock->dirty_size;
233                 c->nextblock->dirty_size = 0;
234         }
235 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
236         if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
237                 /* If we're going to start writing into a block which already
238                    contains data, and the end of the data isn't page-aligned,
239                    skip a little and align it. */
240
241                 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
242
243                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
244                           skip));
245                 c->nextblock->wasted_size += skip;
246                 c->wasted_size += skip;
247
248                 c->nextblock->free_size -= skip;
249                 c->free_size -= skip;
250         }
251 #endif
252         if (c->nr_erasing_blocks) {
253                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
254                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
255                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
256                         ret = -EIO;
257                         goto out;
258                 }
259                 jffs2_erase_pending_trigger(c);
260         }
261         ret = 0;
262  out:
263         if (buf_size)
264                 kfree(flashbuf);
265 #ifndef __ECOS
266         else
267                 c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
268 #endif
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
318         crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
319         if (crc != je32_to_cpu(rx->node_crc)) {
320                 if (je32_to_cpu(rx->node_crc) != 0xffffffff)
321                         JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
322                                       ofs, je32_to_cpu(rx->node_crc), crc);
323                 DIRTY_SPACE(je32_to_cpu(rx->totlen));
324                 return 0;
325         }
326
327         totlen = PAD(sizeof(*rx) + rx->name_len + 1 + je16_to_cpu(rx->value_len));
328         if (totlen != je32_to_cpu(rx->totlen)) {
329                 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
330                               ofs, je32_to_cpu(rx->totlen), totlen);
331                 DIRTY_SPACE(je32_to_cpu(rx->totlen));
332                 return 0;
333         }
334
335         raw =  jffs2_alloc_raw_node_ref();
336         if (!raw)
337                 return -ENOMEM;
338
339         xd = jffs2_setup_xattr_datum(c, je32_to_cpu(rx->xid), je32_to_cpu(rx->version));
340         if (IS_ERR(xd)) {
341                 jffs2_free_raw_node_ref(raw);
342                 if (PTR_ERR(xd) == -EEXIST) {
343                         DIRTY_SPACE(PAD(je32_to_cpu(rx->totlen)));
344                         return 0;
345                 }
346                 return PTR_ERR(xd);
347         }
348         xd->xprefix = rx->xprefix;
349         xd->name_len = rx->name_len;
350         xd->value_len = je16_to_cpu(rx->value_len);
351         xd->data_crc = je32_to_cpu(rx->data_crc);
352         xd->node = raw;
353
354         raw->__totlen = totlen;
355         raw->flash_offset = ofs | REF_PRISTINE;
356         raw->next_phys = NULL;
357         raw->next_in_ino = (void *)xd;
358         if (!jeb->first_node)
359                 jeb->first_node = raw;
360         if (jeb->last_node)
361                 jeb->last_node->next_phys = raw;
362         jeb->last_node = raw;
363
364         USED_SPACE(PAD(je32_to_cpu(rx->totlen)));
365         if (jffs2_sum_active())
366                 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
367         dbg_xattr("scaning xdatum at %#08x (xid=%u, version=%u)\n",
368                   ofs, xd->xid, xd->version);
369         return 0;
370 }
371
372 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
373                                 struct jffs2_raw_xref *rr, uint32_t ofs,
374                                 struct jffs2_summary *s)
375 {
376         struct jffs2_xattr_ref *ref;
377         struct jffs2_raw_node_ref *raw;
378         uint32_t crc;
379
380         crc = crc32(0, rr, sizeof(*rr) - 4);
381         if (crc != je32_to_cpu(rr->node_crc)) {
382                 if (je32_to_cpu(rr->node_crc) != 0xffffffff)
383                         JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
384                                       ofs, je32_to_cpu(rr->node_crc), crc);
385                 DIRTY_SPACE(PAD(je32_to_cpu(rr->totlen)));
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                 DIRTY_SPACE(je32_to_cpu(rr->totlen));
394                 return 0;
395         }
396
397         ref = jffs2_alloc_xattr_ref();
398         if (!ref)
399                 return -ENOMEM;
400
401         raw =  jffs2_alloc_raw_node_ref();
402         if (!raw) {
403                 jffs2_free_xattr_ref(ref);
404                 return -ENOMEM;
405         }
406
407         /* BEFORE jffs2_build_xattr_subsystem() called, 
408          * ref->xid is used to store 32bit xid, xd is not used
409          * ref->ino is used to store 32bit inode-number, ic is not used
410          * Thoes variables are declared as union, thus using those
411          * are exclusive. In a similar way, ref->next is temporarily
412          * used to chain all xattr_ref object. It's re-chained to
413          * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
414          */
415         ref->node = raw;
416         ref->ino = je32_to_cpu(rr->ino);
417         ref->xid = je32_to_cpu(rr->xid);
418         ref->next = c->xref_temp;
419         c->xref_temp = ref;
420
421         raw->__totlen = PAD(je32_to_cpu(rr->totlen));
422         raw->flash_offset = ofs | REF_PRISTINE;
423         raw->next_phys = NULL;
424         raw->next_in_ino = (void *)ref;
425         if (!jeb->first_node)
426                 jeb->first_node = raw;
427         if (jeb->last_node)
428                 jeb->last_node->next_phys = raw;
429         jeb->last_node = raw;
430
431         USED_SPACE(PAD(je32_to_cpu(rr->totlen)));       
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 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
441                                 unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
442         struct jffs2_unknown_node *node;
443         struct jffs2_unknown_node crcnode;
444         struct jffs2_sum_marker *sm;
445         uint32_t ofs, prevofs;
446         uint32_t hdr_crc, buf_ofs, buf_len;
447         int err;
448         int noise = 0;
449
450
451 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
452         int cleanmarkerfound = 0;
453 #endif
454
455         ofs = jeb->offset;
456         prevofs = jeb->offset - 1;
457
458         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
459
460 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
461         if (jffs2_cleanmarker_oob(c)) {
462                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
463                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
464                 /* Even if it's not found, we still scan to see
465                    if the block is empty. We use this information
466                    to decide whether to erase it or not. */
467                 switch (ret) {
468                 case 0:         cleanmarkerfound = 1; break;
469                 case 1:         break;
470                 case 2:         return BLK_STATE_BADBLOCK;
471                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
472                 default:        return ret;
473                 }
474         }
475 #endif
476
477         if (jffs2_sum_active()) {
478                 sm = kmalloc(sizeof(struct jffs2_sum_marker), GFP_KERNEL);
479                 if (!sm) {
480                         return -ENOMEM;
481                 }
482
483                 err = jffs2_fill_scan_buf(c, (unsigned char *) sm, jeb->offset + c->sector_size -
484                                         sizeof(struct jffs2_sum_marker), sizeof(struct jffs2_sum_marker));
485                 if (err) {
486                         kfree(sm);
487                         return err;
488                 }
489
490                 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC ) {
491                         err = jffs2_sum_scan_sumnode(c, jeb, je32_to_cpu(sm->offset), &pseudo_random);
492                         if (err) {
493                                 kfree(sm);
494                                 return err;
495                         }
496                 }
497
498                 kfree(sm);
499
500                 ofs = jeb->offset;
501                 prevofs = jeb->offset - 1;
502         }
503
504         buf_ofs = jeb->offset;
505
506         if (!buf_size) {
507                 buf_len = c->sector_size;
508
509                 if (jffs2_sum_active()) {
510                         /* must reread because of summary test */
511                         err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
512                         if (err)
513                                 return err;
514                 }
515
516         } else {
517                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
518                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
519                 if (err)
520                         return err;
521         }
522
523         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
524         ofs = 0;
525
526         /* Scan only 4KiB of 0xFF before declaring it's empty */
527         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
528                 ofs += 4;
529
530         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
531 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
532                 if (jffs2_cleanmarker_oob(c)) {
533                         /* scan oob, take care of cleanmarker */
534                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
535                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
536                         switch (ret) {
537                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
538                         case 1:         return BLK_STATE_ALLDIRTY;
539                         default:        return ret;
540                         }
541                 }
542 #endif
543                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
544                 if (c->cleanmarker_size == 0)
545                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
546                 else
547                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
548         }
549         if (ofs) {
550                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
551                           jeb->offset + ofs));
552                 DIRTY_SPACE(ofs);
553         }
554
555         /* Now ofs is a complete physical flash offset as it always was... */
556         ofs += jeb->offset;
557
558         noise = 10;
559
560         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
561
562 scan_more:
563         while(ofs < jeb->offset + c->sector_size) {
564
565                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
566
567                 cond_resched();
568
569                 if (ofs & 3) {
570                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
571                         ofs = PAD(ofs);
572                         continue;
573                 }
574                 if (ofs == prevofs) {
575                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
576                         DIRTY_SPACE(4);
577                         ofs += 4;
578                         continue;
579                 }
580                 prevofs = ofs;
581
582                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
583                         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),
584                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
585                         DIRTY_SPACE((jeb->offset + c->sector_size)-ofs);
586                         break;
587                 }
588
589                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
590                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
591                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
592                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
593                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
594                         if (err)
595                                 return err;
596                         buf_ofs = ofs;
597                 }
598
599                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
600
601                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
602                         uint32_t inbuf_ofs;
603                         uint32_t empty_start;
604
605                         empty_start = ofs;
606                         ofs += 4;
607
608                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
609                 more_empty:
610                         inbuf_ofs = ofs - buf_ofs;
611                         while (inbuf_ofs < buf_len) {
612                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
613                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
614                                                empty_start, ofs);
615                                         DIRTY_SPACE(ofs-empty_start);
616                                         goto scan_more;
617                                 }
618
619                                 inbuf_ofs+=4;
620                                 ofs += 4;
621                         }
622                         /* Ran off end. */
623                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
624
625                         /* If we're only checking the beginning of a block with a cleanmarker,
626                            bail now */
627                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
628                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_phys) {
629                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
630                                 return BLK_STATE_CLEANMARKER;
631                         }
632
633                         /* See how much more there is to read in this eraseblock... */
634                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
635                         if (!buf_len) {
636                                 /* No more to read. Break out of main loop without marking
637                                    this range of empty space as dirty (because it's not) */
638                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
639                                           empty_start));
640                                 break;
641                         }
642                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
643                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
644                         if (err)
645                                 return err;
646                         buf_ofs = ofs;
647                         goto more_empty;
648                 }
649
650                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
651                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
652                         DIRTY_SPACE(4);
653                         ofs += 4;
654                         continue;
655                 }
656                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
657                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
658                         DIRTY_SPACE(4);
659                         ofs += 4;
660                         continue;
661                 }
662                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
663                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
664                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
665                         DIRTY_SPACE(4);
666                         ofs += 4;
667                         continue;
668                 }
669                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
670                         /* OK. We're out of possibilities. Whinge and move on */
671                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
672                                      JFFS2_MAGIC_BITMASK, ofs,
673                                      je16_to_cpu(node->magic));
674                         DIRTY_SPACE(4);
675                         ofs += 4;
676                         continue;
677                 }
678                 /* We seem to have a node of sorts. Check the CRC */
679                 crcnode.magic = node->magic;
680                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
681                 crcnode.totlen = node->totlen;
682                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
683
684                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
685                         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",
686                                      ofs, je16_to_cpu(node->magic),
687                                      je16_to_cpu(node->nodetype),
688                                      je32_to_cpu(node->totlen),
689                                      je32_to_cpu(node->hdr_crc),
690                                      hdr_crc);
691                         DIRTY_SPACE(4);
692                         ofs += 4;
693                         continue;
694                 }
695
696                 if (ofs + je32_to_cpu(node->totlen) >
697                     jeb->offset + c->sector_size) {
698                         /* Eep. Node goes over the end of the erase block. */
699                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
700                                ofs, je32_to_cpu(node->totlen));
701                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
702                         DIRTY_SPACE(4);
703                         ofs += 4;
704                         continue;
705                 }
706
707                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
708                         /* Wheee. This is an obsoleted node */
709                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
710                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
711                         ofs += PAD(je32_to_cpu(node->totlen));
712                         continue;
713                 }
714
715                 switch(je16_to_cpu(node->nodetype)) {
716                 case JFFS2_NODETYPE_INODE:
717                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
718                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
719                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
720                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
721                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
722                                 if (err)
723                                         return err;
724                                 buf_ofs = ofs;
725                                 node = (void *)buf;
726                         }
727                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
728                         if (err) return err;
729                         ofs += PAD(je32_to_cpu(node->totlen));
730                         break;
731
732                 case JFFS2_NODETYPE_DIRENT:
733                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
734                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
735                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
736                                           je32_to_cpu(node->totlen), buf_len, ofs));
737                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
738                                 if (err)
739                                         return err;
740                                 buf_ofs = ofs;
741                                 node = (void *)buf;
742                         }
743                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
744                         if (err) return err;
745                         ofs += PAD(je32_to_cpu(node->totlen));
746                         break;
747
748 #ifdef CONFIG_JFFS2_FS_XATTR
749                 case JFFS2_NODETYPE_XATTR:
750                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
751                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
752                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
753                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
754                                           je32_to_cpu(node->totlen), buf_len, ofs));
755                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
756                                 if (err)
757                                         return err;
758                                 buf_ofs = ofs;
759                                 node = (void *)buf;
760                         }
761                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
762                         if (err)
763                                 return err;
764                         ofs += PAD(je32_to_cpu(node->totlen));
765                         break;
766                 case JFFS2_NODETYPE_XREF:
767                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
768                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
769                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
770                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
771                                           je32_to_cpu(node->totlen), buf_len, ofs));
772                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
773                                 if (err)
774                                         return err;
775                                 buf_ofs = ofs;
776                                 node = (void *)buf;
777                         }
778                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
779                         if (err)
780                                 return err;
781                         ofs += PAD(je32_to_cpu(node->totlen));
782                         break;
783 #endif  /* CONFIG_JFFS2_FS_XATTR */
784
785                 case JFFS2_NODETYPE_CLEANMARKER:
786                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
787                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
788                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
789                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
790                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
791                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
792                         } else if (jeb->first_node) {
793                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
794                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
795                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
796                         } else {
797                                 struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
798                                 if (!marker_ref) {
799                                         printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
800                                         return -ENOMEM;
801                                 }
802                                 marker_ref->next_in_ino = NULL;
803                                 marker_ref->next_phys = NULL;
804                                 marker_ref->flash_offset = ofs | REF_NORMAL;
805                                 marker_ref->__totlen = c->cleanmarker_size;
806                                 jeb->first_node = jeb->last_node = marker_ref;
807
808                                 USED_SPACE(PAD(c->cleanmarker_size));
809                                 ofs += PAD(c->cleanmarker_size);
810                         }
811                         break;
812
813                 case JFFS2_NODETYPE_PADDING:
814                         if (jffs2_sum_active())
815                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
816                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
817                         ofs += PAD(je32_to_cpu(node->totlen));
818                         break;
819
820                 default:
821                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
822                         case JFFS2_FEATURE_ROCOMPAT:
823                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
824                                 c->flags |= JFFS2_SB_FLAG_RO;
825                                 if (!(jffs2_is_readonly(c)))
826                                         return -EROFS;
827                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
828                                 ofs += PAD(je32_to_cpu(node->totlen));
829                                 break;
830
831                         case JFFS2_FEATURE_INCOMPAT:
832                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
833                                 return -EINVAL;
834
835                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
836                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
837                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
838                                 ofs += PAD(je32_to_cpu(node->totlen));
839                                 break;
840
841                         case JFFS2_FEATURE_RWCOMPAT_COPY:
842                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
843                                 USED_SPACE(PAD(je32_to_cpu(node->totlen)));
844                                 ofs += PAD(je32_to_cpu(node->totlen));
845                                 break;
846                         }
847                 }
848         }
849
850         if (jffs2_sum_active()) {
851                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
852                         dbg_summary("There is not enough space for "
853                                 "summary information, disabling for this jeb!\n");
854                         jffs2_sum_disable_collecting(s);
855                 }
856         }
857
858         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset,
859                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
860
861         /* mark_node_obsolete can add to wasted !! */
862         if (jeb->wasted_size) {
863                 jeb->dirty_size += jeb->wasted_size;
864                 c->dirty_size += jeb->wasted_size;
865                 c->wasted_size -= jeb->wasted_size;
866                 jeb->wasted_size = 0;
867         }
868
869         return jffs2_scan_classify_jeb(c, jeb);
870 }
871
872 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
873 {
874         struct jffs2_inode_cache *ic;
875
876         ic = jffs2_get_ino_cache(c, ino);
877         if (ic)
878                 return ic;
879
880         if (ino > c->highest_ino)
881                 c->highest_ino = ino;
882
883         ic = jffs2_alloc_inode_cache();
884         if (!ic) {
885                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
886                 return NULL;
887         }
888         memset(ic, 0, sizeof(*ic));
889
890         ic->ino = ino;
891         ic->nodes = (void *)ic;
892         jffs2_add_ino_cache(c, ic);
893         if (ino == 1)
894                 ic->nlink = 1;
895         return ic;
896 }
897
898 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
899                                  struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
900 {
901         struct jffs2_raw_node_ref *raw;
902         struct jffs2_inode_cache *ic;
903         uint32_t ino = je32_to_cpu(ri->ino);
904
905         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
906
907         /* We do very little here now. Just check the ino# to which we should attribute
908            this node; we can do all the CRC checking etc. later. There's a tradeoff here --
909            we used to scan the flash once only, reading everything we want from it into
910            memory, then building all our in-core data structures and freeing the extra
911            information. Now we allow the first part of the mount to complete a lot quicker,
912            but we have to go _back_ to the flash in order to finish the CRC checking, etc.
913            Which means that the _full_ amount of time to get to proper write mode with GC
914            operational may actually be _longer_ than before. Sucks to be me. */
915
916         raw = jffs2_alloc_raw_node_ref();
917         if (!raw) {
918                 printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node reference failed\n");
919                 return -ENOMEM;
920         }
921
922         ic = jffs2_get_ino_cache(c, ino);
923         if (!ic) {
924                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
925                    first node we found for this inode. Do a CRC check to protect against the former
926                    case */
927                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
928
929                 if (crc != je32_to_cpu(ri->node_crc)) {
930                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
931                                ofs, je32_to_cpu(ri->node_crc), crc);
932                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
933                         DIRTY_SPACE(PAD(je32_to_cpu(ri->totlen)));
934                         jffs2_free_raw_node_ref(raw);
935                         return 0;
936                 }
937                 ic = jffs2_scan_make_ino_cache(c, ino);
938                 if (!ic) {
939                         jffs2_free_raw_node_ref(raw);
940                         return -ENOMEM;
941                 }
942         }
943
944         /* Wheee. It worked */
945
946         raw->flash_offset = ofs | REF_UNCHECKED;
947         raw->__totlen = PAD(je32_to_cpu(ri->totlen));
948         raw->next_phys = NULL;
949         raw->next_in_ino = ic->nodes;
950
951         ic->nodes = raw;
952         if (!jeb->first_node)
953                 jeb->first_node = raw;
954         if (jeb->last_node)
955                 jeb->last_node->next_phys = raw;
956         jeb->last_node = raw;
957
958         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
959                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
960                   je32_to_cpu(ri->offset),
961                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
962
963         pseudo_random += je32_to_cpu(ri->version);
964
965         UNCHECKED_SPACE(PAD(je32_to_cpu(ri->totlen)));
966
967         if (jffs2_sum_active()) {
968                 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
969         }
970
971         return 0;
972 }
973
974 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
975                                   struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
976 {
977         struct jffs2_raw_node_ref *raw;
978         struct jffs2_full_dirent *fd;
979         struct jffs2_inode_cache *ic;
980         uint32_t crc;
981
982         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
983
984         /* We don't get here unless the node is still valid, so we don't have to
985            mask in the ACCURATE bit any more. */
986         crc = crc32(0, rd, sizeof(*rd)-8);
987
988         if (crc != je32_to_cpu(rd->node_crc)) {
989                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
990                        ofs, je32_to_cpu(rd->node_crc), crc);
991                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
992                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
993                 return 0;
994         }
995
996         pseudo_random += je32_to_cpu(rd->version);
997
998         fd = jffs2_alloc_full_dirent(rd->nsize+1);
999         if (!fd) {
1000                 return -ENOMEM;
1001         }
1002         memcpy(&fd->name, rd->name, rd->nsize);
1003         fd->name[rd->nsize] = 0;
1004
1005         crc = crc32(0, fd->name, rd->nsize);
1006         if (crc != je32_to_cpu(rd->name_crc)) {
1007                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1008                        ofs, je32_to_cpu(rd->name_crc), crc);
1009                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
1010                 jffs2_free_full_dirent(fd);
1011                 /* FIXME: Why do we believe totlen? */
1012                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1013                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
1014                 return 0;
1015         }
1016         raw = jffs2_alloc_raw_node_ref();
1017         if (!raw) {
1018                 jffs2_free_full_dirent(fd);
1019                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node reference failed\n");
1020                 return -ENOMEM;
1021         }
1022         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1023         if (!ic) {
1024                 jffs2_free_full_dirent(fd);
1025                 jffs2_free_raw_node_ref(raw);
1026                 return -ENOMEM;
1027         }
1028
1029         raw->__totlen = PAD(je32_to_cpu(rd->totlen));
1030         raw->flash_offset = ofs | REF_PRISTINE;
1031         raw->next_phys = NULL;
1032         raw->next_in_ino = ic->nodes;
1033         ic->nodes = raw;
1034         if (!jeb->first_node)
1035                 jeb->first_node = raw;
1036         if (jeb->last_node)
1037                 jeb->last_node->next_phys = raw;
1038         jeb->last_node = raw;
1039
1040         fd->raw = raw;
1041         fd->next = NULL;
1042         fd->version = je32_to_cpu(rd->version);
1043         fd->ino = je32_to_cpu(rd->ino);
1044         fd->nhash = full_name_hash(fd->name, rd->nsize);
1045         fd->type = rd->type;
1046         USED_SPACE(PAD(je32_to_cpu(rd->totlen)));
1047         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1048
1049         if (jffs2_sum_active()) {
1050                 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1051         }
1052
1053         return 0;
1054 }
1055
1056 static int count_list(struct list_head *l)
1057 {
1058         uint32_t count = 0;
1059         struct list_head *tmp;
1060
1061         list_for_each(tmp, l) {
1062                 count++;
1063         }
1064         return count;
1065 }
1066
1067 /* Note: This breaks if list_empty(head). I don't care. You
1068    might, if you copy this code and use it elsewhere :) */
1069 static void rotate_list(struct list_head *head, uint32_t count)
1070 {
1071         struct list_head *n = head->next;
1072
1073         list_del(head);
1074         while(count--) {
1075                 n = n->next;
1076         }
1077         list_add(head, n);
1078 }
1079
1080 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1081 {
1082         uint32_t x;
1083         uint32_t rotateby;
1084
1085         x = count_list(&c->clean_list);
1086         if (x) {
1087                 rotateby = pseudo_random % x;
1088                 rotate_list((&c->clean_list), rotateby);
1089         }
1090
1091         x = count_list(&c->very_dirty_list);
1092         if (x) {
1093                 rotateby = pseudo_random % x;
1094                 rotate_list((&c->very_dirty_list), rotateby);
1095         }
1096
1097         x = count_list(&c->dirty_list);
1098         if (x) {
1099                 rotateby = pseudo_random % x;
1100                 rotate_list((&c->dirty_list), rotateby);
1101         }
1102
1103         x = count_list(&c->erasable_list);
1104         if (x) {
1105                 rotateby = pseudo_random % x;
1106                 rotate_list((&c->erasable_list), rotateby);
1107         }
1108
1109         if (c->nr_erasing_blocks) {
1110                 rotateby = pseudo_random % c->nr_erasing_blocks;
1111                 rotate_list((&c->erase_pending_list), rotateby);
1112         }
1113
1114         if (c->nr_free_blocks) {
1115                 rotateby = pseudo_random % c->nr_free_blocks;
1116                 rotate_list((&c->free_list), rotateby);
1117         }
1118 }