[JFFS2][XATTR] XATTR support on JFFS2 (version. 5)
[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->ilist 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         list_add_tail(&ref->ilist, &c->xattr_temp);
419
420         raw->__totlen = PAD(je32_to_cpu(rr->totlen));
421         raw->flash_offset = ofs | REF_PRISTINE;
422         raw->next_phys = NULL;
423         raw->next_in_ino = (void *)ref;
424         if (!jeb->first_node)
425                 jeb->first_node = raw;
426         if (jeb->last_node)
427                 jeb->last_node->next_phys = raw;
428         jeb->last_node = raw;
429
430         USED_SPACE(PAD(je32_to_cpu(rr->totlen)));       
431         if (jffs2_sum_active())
432                 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
433         dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
434                   ofs, ref->xid, ref->ino);
435         return 0;
436 }
437 #endif
438
439 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
440                                 unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
441         struct jffs2_unknown_node *node;
442         struct jffs2_unknown_node crcnode;
443         struct jffs2_sum_marker *sm;
444         uint32_t ofs, prevofs;
445         uint32_t hdr_crc, buf_ofs, buf_len;
446         int err;
447         int noise = 0;
448
449
450 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
451         int cleanmarkerfound = 0;
452 #endif
453
454         ofs = jeb->offset;
455         prevofs = jeb->offset - 1;
456
457         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
458
459 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
460         if (jffs2_cleanmarker_oob(c)) {
461                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
462                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
463                 /* Even if it's not found, we still scan to see
464                    if the block is empty. We use this information
465                    to decide whether to erase it or not. */
466                 switch (ret) {
467                 case 0:         cleanmarkerfound = 1; break;
468                 case 1:         break;
469                 case 2:         return BLK_STATE_BADBLOCK;
470                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
471                 default:        return ret;
472                 }
473         }
474 #endif
475
476         if (jffs2_sum_active()) {
477                 sm = kmalloc(sizeof(struct jffs2_sum_marker), GFP_KERNEL);
478                 if (!sm) {
479                         return -ENOMEM;
480                 }
481
482                 err = jffs2_fill_scan_buf(c, (unsigned char *) sm, jeb->offset + c->sector_size -
483                                         sizeof(struct jffs2_sum_marker), sizeof(struct jffs2_sum_marker));
484                 if (err) {
485                         kfree(sm);
486                         return err;
487                 }
488
489                 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC ) {
490                         err = jffs2_sum_scan_sumnode(c, jeb, je32_to_cpu(sm->offset), &pseudo_random);
491                         if (err) {
492                                 kfree(sm);
493                                 return err;
494                         }
495                 }
496
497                 kfree(sm);
498
499                 ofs = jeb->offset;
500                 prevofs = jeb->offset - 1;
501         }
502
503         buf_ofs = jeb->offset;
504
505         if (!buf_size) {
506                 buf_len = c->sector_size;
507
508                 if (jffs2_sum_active()) {
509                         /* must reread because of summary test */
510                         err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
511                         if (err)
512                                 return err;
513                 }
514
515         } else {
516                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
517                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
518                 if (err)
519                         return err;
520         }
521
522         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
523         ofs = 0;
524
525         /* Scan only 4KiB of 0xFF before declaring it's empty */
526         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
527                 ofs += 4;
528
529         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
530 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
531                 if (jffs2_cleanmarker_oob(c)) {
532                         /* scan oob, take care of cleanmarker */
533                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
534                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
535                         switch (ret) {
536                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
537                         case 1:         return BLK_STATE_ALLDIRTY;
538                         default:        return ret;
539                         }
540                 }
541 #endif
542                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
543                 if (c->cleanmarker_size == 0)
544                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
545                 else
546                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
547         }
548         if (ofs) {
549                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
550                           jeb->offset + ofs));
551                 DIRTY_SPACE(ofs);
552         }
553
554         /* Now ofs is a complete physical flash offset as it always was... */
555         ofs += jeb->offset;
556
557         noise = 10;
558
559         dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
560
561 scan_more:
562         while(ofs < jeb->offset + c->sector_size) {
563
564                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
565
566                 cond_resched();
567
568                 if (ofs & 3) {
569                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
570                         ofs = PAD(ofs);
571                         continue;
572                 }
573                 if (ofs == prevofs) {
574                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
575                         DIRTY_SPACE(4);
576                         ofs += 4;
577                         continue;
578                 }
579                 prevofs = ofs;
580
581                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
582                         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),
583                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
584                         DIRTY_SPACE((jeb->offset + c->sector_size)-ofs);
585                         break;
586                 }
587
588                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
589                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
590                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
591                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
592                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
593                         if (err)
594                                 return err;
595                         buf_ofs = ofs;
596                 }
597
598                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
599
600                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
601                         uint32_t inbuf_ofs;
602                         uint32_t empty_start;
603
604                         empty_start = ofs;
605                         ofs += 4;
606
607                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
608                 more_empty:
609                         inbuf_ofs = ofs - buf_ofs;
610                         while (inbuf_ofs < buf_len) {
611                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
612                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
613                                                empty_start, ofs);
614                                         DIRTY_SPACE(ofs-empty_start);
615                                         goto scan_more;
616                                 }
617
618                                 inbuf_ofs+=4;
619                                 ofs += 4;
620                         }
621                         /* Ran off end. */
622                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
623
624                         /* If we're only checking the beginning of a block with a cleanmarker,
625                            bail now */
626                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
627                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_phys) {
628                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
629                                 return BLK_STATE_CLEANMARKER;
630                         }
631
632                         /* See how much more there is to read in this eraseblock... */
633                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
634                         if (!buf_len) {
635                                 /* No more to read. Break out of main loop without marking
636                                    this range of empty space as dirty (because it's not) */
637                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
638                                           empty_start));
639                                 break;
640                         }
641                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
642                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
643                         if (err)
644                                 return err;
645                         buf_ofs = ofs;
646                         goto more_empty;
647                 }
648
649                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
650                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
651                         DIRTY_SPACE(4);
652                         ofs += 4;
653                         continue;
654                 }
655                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
656                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
657                         DIRTY_SPACE(4);
658                         ofs += 4;
659                         continue;
660                 }
661                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
662                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
663                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
664                         DIRTY_SPACE(4);
665                         ofs += 4;
666                         continue;
667                 }
668                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
669                         /* OK. We're out of possibilities. Whinge and move on */
670                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
671                                      JFFS2_MAGIC_BITMASK, ofs,
672                                      je16_to_cpu(node->magic));
673                         DIRTY_SPACE(4);
674                         ofs += 4;
675                         continue;
676                 }
677                 /* We seem to have a node of sorts. Check the CRC */
678                 crcnode.magic = node->magic;
679                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
680                 crcnode.totlen = node->totlen;
681                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
682
683                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
684                         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",
685                                      ofs, je16_to_cpu(node->magic),
686                                      je16_to_cpu(node->nodetype),
687                                      je32_to_cpu(node->totlen),
688                                      je32_to_cpu(node->hdr_crc),
689                                      hdr_crc);
690                         DIRTY_SPACE(4);
691                         ofs += 4;
692                         continue;
693                 }
694
695                 if (ofs + je32_to_cpu(node->totlen) >
696                     jeb->offset + c->sector_size) {
697                         /* Eep. Node goes over the end of the erase block. */
698                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
699                                ofs, je32_to_cpu(node->totlen));
700                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
701                         DIRTY_SPACE(4);
702                         ofs += 4;
703                         continue;
704                 }
705
706                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
707                         /* Wheee. This is an obsoleted node */
708                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
709                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
710                         ofs += PAD(je32_to_cpu(node->totlen));
711                         continue;
712                 }
713
714                 switch(je16_to_cpu(node->nodetype)) {
715                 case JFFS2_NODETYPE_INODE:
716                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
717                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
718                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
719                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
720                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
721                                 if (err)
722                                         return err;
723                                 buf_ofs = ofs;
724                                 node = (void *)buf;
725                         }
726                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
727                         if (err) return err;
728                         ofs += PAD(je32_to_cpu(node->totlen));
729                         break;
730
731                 case JFFS2_NODETYPE_DIRENT:
732                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
733                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
734                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
735                                           je32_to_cpu(node->totlen), buf_len, ofs));
736                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
737                                 if (err)
738                                         return err;
739                                 buf_ofs = ofs;
740                                 node = (void *)buf;
741                         }
742                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
743                         if (err) return err;
744                         ofs += PAD(je32_to_cpu(node->totlen));
745                         break;
746
747 #ifdef CONFIG_JFFS2_FS_XATTR
748                 case JFFS2_NODETYPE_XATTR:
749                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
750                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
751                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
752                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
753                                           je32_to_cpu(node->totlen), buf_len, ofs));
754                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
755                                 if (err)
756                                         return err;
757                                 buf_ofs = ofs;
758                                 node = (void *)buf;
759                         }
760                         err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
761                         if (err)
762                                 return err;
763                         ofs += PAD(je32_to_cpu(node->totlen));
764                         break;
765                 case JFFS2_NODETYPE_XREF:
766                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
767                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
768                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
769                                           " left to end of buf. Reading 0x%x at 0x%08x\n",
770                                           je32_to_cpu(node->totlen), buf_len, ofs));
771                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
772                                 if (err)
773                                         return err;
774                                 buf_ofs = ofs;
775                                 node = (void *)buf;
776                         }
777                         err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
778                         if (err)
779                                 return err;
780                         ofs += PAD(je32_to_cpu(node->totlen));
781                         break;
782 #endif  /* CONFIG_JFFS2_FS_XATTR */
783
784                 case JFFS2_NODETYPE_CLEANMARKER:
785                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
786                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
787                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
788                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
789                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
790                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
791                         } else if (jeb->first_node) {
792                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
793                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
794                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
795                         } else {
796                                 struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
797                                 if (!marker_ref) {
798                                         printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
799                                         return -ENOMEM;
800                                 }
801                                 marker_ref->next_in_ino = NULL;
802                                 marker_ref->next_phys = NULL;
803                                 marker_ref->flash_offset = ofs | REF_NORMAL;
804                                 marker_ref->__totlen = c->cleanmarker_size;
805                                 jeb->first_node = jeb->last_node = marker_ref;
806
807                                 USED_SPACE(PAD(c->cleanmarker_size));
808                                 ofs += PAD(c->cleanmarker_size);
809                         }
810                         break;
811
812                 case JFFS2_NODETYPE_PADDING:
813                         if (jffs2_sum_active())
814                                 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
815                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
816                         ofs += PAD(je32_to_cpu(node->totlen));
817                         break;
818
819                 default:
820                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
821                         case JFFS2_FEATURE_ROCOMPAT:
822                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
823                                 c->flags |= JFFS2_SB_FLAG_RO;
824                                 if (!(jffs2_is_readonly(c)))
825                                         return -EROFS;
826                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
827                                 ofs += PAD(je32_to_cpu(node->totlen));
828                                 break;
829
830                         case JFFS2_FEATURE_INCOMPAT:
831                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
832                                 return -EINVAL;
833
834                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
835                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
836                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
837                                 ofs += PAD(je32_to_cpu(node->totlen));
838                                 break;
839
840                         case JFFS2_FEATURE_RWCOMPAT_COPY:
841                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
842                                 USED_SPACE(PAD(je32_to_cpu(node->totlen)));
843                                 ofs += PAD(je32_to_cpu(node->totlen));
844                                 break;
845                         }
846                 }
847         }
848
849         if (jffs2_sum_active()) {
850                 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
851                         dbg_summary("There is not enough space for "
852                                 "summary information, disabling for this jeb!\n");
853                         jffs2_sum_disable_collecting(s);
854                 }
855         }
856
857         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset,
858                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
859
860         /* mark_node_obsolete can add to wasted !! */
861         if (jeb->wasted_size) {
862                 jeb->dirty_size += jeb->wasted_size;
863                 c->dirty_size += jeb->wasted_size;
864                 c->wasted_size -= jeb->wasted_size;
865                 jeb->wasted_size = 0;
866         }
867
868         return jffs2_scan_classify_jeb(c, jeb);
869 }
870
871 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
872 {
873         struct jffs2_inode_cache *ic;
874
875         ic = jffs2_get_ino_cache(c, ino);
876         if (ic)
877                 return ic;
878
879         if (ino > c->highest_ino)
880                 c->highest_ino = ino;
881
882         ic = jffs2_alloc_inode_cache();
883         if (!ic) {
884                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
885                 return NULL;
886         }
887         memset(ic, 0, sizeof(*ic));
888
889         ic->ino = ino;
890         ic->nodes = (void *)ic;
891         init_xattr_inode_cache(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 }