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OMAPDSS: VENC: fix NULL pointer dereference in DSS2 VENC sysfs debug attr on OMAP4
[zen-stable.git] / fs / jffs2 / scan.c
blobf99464833bb2fb6e1ce886a713706b0bd88413ff
1 /*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright © 2001-2007 Red Hat, Inc.
5 *
6 * Created by David Woodhouse <dwmw2@infradead.org>
7 *
8 * For licensing information, see the file 'LICENCE' in this directory.
9 *
10 */
11
12 #include <linux/kernel.h>
13 #include <linux/sched.h>
14 #include <linux/slab.h>
15 #include <linux/mtd/mtd.h>
16 #include <linux/pagemap.h>
17 #include <linux/crc32.h>
18 #include <linux/compiler.h>
19 #include "nodelist.h"
20 #include "summary.h"
21 #include "debug.h"
22
23 #define DEFAULT_EMPTY_SCAN_SIZE 256
24
25 #define noisy_printk(noise, args...) do { \
26 if (*(noise)) { \
27 printk(KERN_NOTICE args); \
28 (*(noise))--; \
29 if (!(*(noise))) { \
30 printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \
31 } \
32 } \
33 } while(0)
34
35 static uint32_t pseudo_random;
36
37 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
38 unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);
39
40 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
41 * Returning an error will abort the mount - bad checksums etc. should just mark the space
42 * as dirty.
43 */
44 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
45 struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);
46 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
47 struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);
48
49 static inline int min_free(struct jffs2_sb_info *c)
50 {
51 uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
52 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
53 if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
54 return c->wbuf_pagesize;
55 #endif
56 return min;
57
58 }
59
60 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
61 if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
62 return sector_size;
63 else
64 return DEFAULT_EMPTY_SCAN_SIZE;
65 }
66
67 static int file_dirty(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
68 {
69 int ret;
70
71 if ((ret = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
72 return ret;
73 if ((ret = jffs2_scan_dirty_space(c, jeb, jeb->free_size)))
74 return ret;
75 /* Turned wasted size into dirty, since we apparently
76 think it's recoverable now. */
77 jeb->dirty_size += jeb->wasted_size;
78 c->dirty_size += jeb->wasted_size;
79 c->wasted_size -= jeb->wasted_size;
80 jeb->wasted_size = 0;
81 if (VERYDIRTY(c, jeb->dirty_size)) {
82 list_add(&jeb->list, &c->very_dirty_list);
83 } else {
84 list_add(&jeb->list, &c->dirty_list);
85 }
86 return 0;
87 }
88
89 int jffs2_scan_medium(struct jffs2_sb_info *c)
90 {
91 int i, ret;
92 uint32_t empty_blocks = 0, bad_blocks = 0;
93 unsigned char *flashbuf = NULL;
94 uint32_t buf_size = 0;
95 struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
96 #ifndef __ECOS
97 size_t pointlen, try_size;
98
99 if (c->mtd->point) {
100 ret = mtd_point(c->mtd, 0, c->mtd->size, &pointlen,
101 (void **)&flashbuf, NULL);
102 if (!ret && pointlen < c->mtd->size) {
103 /* Don't muck about if it won't let us point to the whole flash */
104 D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
105 mtd_unpoint(c->mtd, 0, pointlen);
106 flashbuf = NULL;
107 }
108 if (ret && ret != -EOPNOTSUPP)
109 D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
110 }
111 #endif
112 if (!flashbuf) {
113 /* For NAND it's quicker to read a whole eraseblock at a time,
114 apparently */
115 if (jffs2_cleanmarker_oob(c))
116 try_size = c->sector_size;
117 else
118 try_size = PAGE_SIZE;
119
120 D1(printk(KERN_DEBUG "Trying to allocate readbuf of %zu "
121 "bytes\n", try_size));
122
123 flashbuf = mtd_kmalloc_up_to(c->mtd, &try_size);
124 if (!flashbuf)
125 return -ENOMEM;
126
127 D1(printk(KERN_DEBUG "Allocated readbuf of %zu bytes\n",
128 try_size));
129
130 buf_size = (uint32_t)try_size;
131 }
132
133 if (jffs2_sum_active()) {
134 s = kzalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
135 if (!s) {
136 JFFS2_WARNING("Can't allocate memory for summary\n");
137 ret = -ENOMEM;
138 goto out;
139 }
140 }
141
142 for (i=0; i<c->nr_blocks; i++) {
143 struct jffs2_eraseblock *jeb = &c->blocks[i];
144
145 cond_resched();
146
147 /* reset summary info for next eraseblock scan */
148 jffs2_sum_reset_collected(s);
149
150 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
151 buf_size, s);
152
153 if (ret < 0)
154 goto out;
155
156 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
157
158 /* Now decide which list to put it on */
159 switch(ret) {
160 case BLK_STATE_ALLFF:
161 /*
162 * Empty block. Since we can't be sure it
163 * was entirely erased, we just queue it for erase
164 * again. It will be marked as such when the erase
165 * is complete. Meanwhile we still count it as empty
166 * for later checks.
167 */
168 empty_blocks++;
169 list_add(&jeb->list, &c->erase_pending_list);
170 c->nr_erasing_blocks++;
171 break;
172
173 case BLK_STATE_CLEANMARKER:
174 /* Only a CLEANMARKER node is valid */
175 if (!jeb->dirty_size) {
176 /* It's actually free */
177 list_add(&jeb->list, &c->free_list);
178 c->nr_free_blocks++;
179 } else {
180 /* Dirt */
181 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
182 list_add(&jeb->list, &c->erase_pending_list);
183 c->nr_erasing_blocks++;
184 }
185 break;
186
187 case BLK_STATE_CLEAN:
188 /* Full (or almost full) of clean data. Clean list */
189 list_add(&jeb->list, &c->clean_list);
190 break;
191
192 case BLK_STATE_PARTDIRTY:
193 /* Some data, but not full. Dirty list. */
194 /* We want to remember the block with most free space
195 and stick it in the 'nextblock' position to start writing to it. */
196 if (jeb->free_size > min_free(c) &&
197 (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
198 /* Better candidate for the next writes to go to */
199 if (c->nextblock) {
200 ret = file_dirty(c, c->nextblock);
201 if (ret)
202 goto out;
203 /* deleting summary information of the old nextblock */
204 jffs2_sum_reset_collected(c->summary);
205 }
206 /* update collected summary information for the current nextblock */
207 jffs2_sum_move_collected(c, s);
208 D1(printk(KERN_DEBUG "jffs2_scan_medium(): new nextblock = 0x%08x\n", jeb->offset));
209 c->nextblock = jeb;
210 } else {
211 ret = file_dirty(c, jeb);
212 if (ret)
213 goto out;
214 }
215 break;
216
217 case BLK_STATE_ALLDIRTY:
218 /* Nothing valid - not even a clean marker. Needs erasing. */
219 /* For now we just put it on the erasing list. We'll start the erases later */
220 D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
221 list_add(&jeb->list, &c->erase_pending_list);
222 c->nr_erasing_blocks++;
223 break;
224
225 case BLK_STATE_BADBLOCK:
226 D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
227 list_add(&jeb->list, &c->bad_list);
228 c->bad_size += c->sector_size;
229 c->free_size -= c->sector_size;
230 bad_blocks++;
231 break;
232 default:
233 printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
234 BUG();
235 }
236 }
237
238 /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
239 if (c->nextblock && (c->nextblock->dirty_size)) {
240 c->nextblock->wasted_size += c->nextblock->dirty_size;
241 c->wasted_size += c->nextblock->dirty_size;
242 c->dirty_size -= c->nextblock->dirty_size;
243 c->nextblock->dirty_size = 0;
244 }
245 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
246 if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
247 /* If we're going to start writing into a block which already
248 contains data, and the end of the data isn't page-aligned,
249 skip a little and align it. */
250
251 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
252
253 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
254 skip));
255 jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);
256 jffs2_scan_dirty_space(c, c->nextblock, skip);
257 }
258 #endif
259 if (c->nr_erasing_blocks) {
260 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
261 printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
262 printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
263 ret = -EIO;
264 goto out;
265 }
266 spin_lock(&c->erase_completion_lock);
267 jffs2_garbage_collect_trigger(c);
268 spin_unlock(&c->erase_completion_lock);
269 }
270 ret = 0;
271 out:
272 if (buf_size)
273 kfree(flashbuf);
274 #ifndef __ECOS
275 else
276 mtd_unpoint(c->mtd, 0, c->mtd->size);
277 #endif
278 kfree(s);
279 return ret;
280 }
281
282 static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf,
283 uint32_t ofs, uint32_t len)
284 {
285 int ret;
286 size_t retlen;
287
288 ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
289 if (ret) {
290 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
291 return ret;
292 }
293 if (retlen < len) {
294 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
295 return -EIO;
296 }
297 return 0;
298 }
299
300 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
301 {
302 if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
303 && (!jeb->first_node || !ref_next(jeb->first_node)) )
304 return BLK_STATE_CLEANMARKER;
305
306 /* move blocks with max 4 byte dirty space to cleanlist */
307 else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
308 c->dirty_size -= jeb->dirty_size;
309 c->wasted_size += jeb->dirty_size;
310 jeb->wasted_size += jeb->dirty_size;
311 jeb->dirty_size = 0;
312 return BLK_STATE_CLEAN;
313 } else if (jeb->used_size || jeb->unchecked_size)
314 return BLK_STATE_PARTDIRTY;
315 else
316 return BLK_STATE_ALLDIRTY;
317 }
318
319 #ifdef CONFIG_JFFS2_FS_XATTR
320 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
321 struct jffs2_raw_xattr *rx, uint32_t ofs,
322 struct jffs2_summary *s)
323 {
324 struct jffs2_xattr_datum *xd;
325 uint32_t xid, version, totlen, crc;
326 int err;
327
328 crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
329 if (crc != je32_to_cpu(rx->node_crc)) {
330 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
331 ofs, je32_to_cpu(rx->node_crc), crc);
332 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
333 return err;
334 return 0;
335 }
336
337 xid = je32_to_cpu(rx->xid);
338 version = je32_to_cpu(rx->version);
339
340 totlen = PAD(sizeof(struct jffs2_raw_xattr)
341 + rx->name_len + 1 + je16_to_cpu(rx->value_len));
342 if (totlen != je32_to_cpu(rx->totlen)) {
343 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
344 ofs, je32_to_cpu(rx->totlen), totlen);
345 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
346 return err;
347 return 0;
348 }
349
350 xd = jffs2_setup_xattr_datum(c, xid, version);
351 if (IS_ERR(xd))
352 return PTR_ERR(xd);
353
354 if (xd->version > version) {
355 struct jffs2_raw_node_ref *raw
356 = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
357 raw->next_in_ino = xd->node->next_in_ino;
358 xd->node->next_in_ino = raw;
359 } else {
360 xd->version = version;
361 xd->xprefix = rx->xprefix;
362 xd->name_len = rx->name_len;
363 xd->value_len = je16_to_cpu(rx->value_len);
364 xd->data_crc = je32_to_cpu(rx->data_crc);
365
366 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
367 }
368
369 if (jffs2_sum_active())
370 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
371 dbg_xattr("scaning xdatum at %#08x (xid=%u, version=%u)\n",
372 ofs, xd->xid, xd->version);
373 return 0;
374 }
375
376 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
377 struct jffs2_raw_xref *rr, uint32_t ofs,
378 struct jffs2_summary *s)
379 {
380 struct jffs2_xattr_ref *ref;
381 uint32_t crc;
382 int err;
383
384 crc = crc32(0, rr, sizeof(*rr) - 4);
385 if (crc != je32_to_cpu(rr->node_crc)) {
386 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
387 ofs, je32_to_cpu(rr->node_crc), crc);
388 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
389 return err;
390 return 0;
391 }
392
393 if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
394 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n",
395 ofs, je32_to_cpu(rr->totlen),
396 PAD(sizeof(struct jffs2_raw_xref)));
397 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
398 return err;
399 return 0;
400 }
401
402 ref = jffs2_alloc_xattr_ref();
403 if (!ref)
404 return -ENOMEM;
405
406 /* BEFORE jffs2_build_xattr_subsystem() called,
407 * and AFTER xattr_ref is marked as a dead xref,
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->ino = je32_to_cpu(rr->ino);
416 ref->xid = je32_to_cpu(rr->xid);
417 ref->xseqno = je32_to_cpu(rr->xseqno);
418 if (ref->xseqno > c->highest_xseqno)
419 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
420 ref->next = c->xref_temp;
421 c->xref_temp = ref;
422
423 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);
424
425 if (jffs2_sum_active())
426 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
427 dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
428 ofs, ref->xid, ref->ino);
429 return 0;
430 }
431 #endif
432
433 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
434 the flash, XIP-style */
435 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
436 unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
437 struct jffs2_unknown_node *node;
438 struct jffs2_unknown_node crcnode;
439 uint32_t ofs, prevofs, max_ofs;
440 uint32_t hdr_crc, buf_ofs, buf_len;
441 int err;
442 int noise = 0;
443
444
445 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
446 int cleanmarkerfound = 0;
447 #endif
448
449 ofs = jeb->offset;
450 prevofs = jeb->offset - 1;
451
452 D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
453
454 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
455 if (jffs2_cleanmarker_oob(c)) {
456 int ret;
457
458 if (mtd_block_isbad(c->mtd, jeb->offset))
459 return BLK_STATE_BADBLOCK;
460
461 ret = jffs2_check_nand_cleanmarker(c, jeb);
462 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
463
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 default: return ret;
471 }
472 }
473 #endif
474
475 if (jffs2_sum_active()) {
476 struct jffs2_sum_marker *sm;
477 void *sumptr = NULL;
478 uint32_t sumlen;
479
480 if (!buf_size) {
481 /* XIP case. Just look, point at the summary if it's there */
482 sm = (void *)buf + c->sector_size - sizeof(*sm);
483 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
484 sumptr = buf + je32_to_cpu(sm->offset);
485 sumlen = c->sector_size - je32_to_cpu(sm->offset);
486 }
487 } else {
488 /* If NAND flash, read a whole page of it. Else just the end */
489 if (c->wbuf_pagesize)
490 buf_len = c->wbuf_pagesize;
491 else
492 buf_len = sizeof(*sm);
493
494 /* Read as much as we want into the _end_ of the preallocated buffer */
495 err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
496 jeb->offset + c->sector_size - buf_len,
497 buf_len);
498 if (err)
499 return err;
500
501 sm = (void *)buf + buf_size - sizeof(*sm);
502 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
503 sumlen = c->sector_size - je32_to_cpu(sm->offset);
504 sumptr = buf + buf_size - sumlen;
505
506 /* Now, make sure the summary itself is available */
507 if (sumlen > buf_size) {
508 /* Need to kmalloc for this. */
509 sumptr = kmalloc(sumlen, GFP_KERNEL);
510 if (!sumptr)
511 return -ENOMEM;
512 memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
513 }
514 if (buf_len < sumlen) {
515 /* Need to read more so that the entire summary node is present */
516 err = jffs2_fill_scan_buf(c, sumptr,
517 jeb->offset + c->sector_size - sumlen,
518 sumlen - buf_len);
519 if (err)
520 return err;
521 }
522 }
523
524 }
525
526 if (sumptr) {
527 err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
528
529 if (buf_size && sumlen > buf_size)
530 kfree(sumptr);
531 /* If it returns with a real error, bail.
532 If it returns positive, that's a block classification
533 (i.e. BLK_STATE_xxx) so return that too.
534 If it returns zero, fall through to full scan. */
535 if (err)
536 return err;
537 }
538 }
539
540 buf_ofs = jeb->offset;
541
542 if (!buf_size) {
543 /* This is the XIP case -- we're reading _directly_ from the flash chip */
544 buf_len = c->sector_size;
545 } else {
546 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
547 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
548 if (err)
549 return err;
550 }
551
552 /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
553 ofs = 0;
554 max_ofs = EMPTY_SCAN_SIZE(c->sector_size);
555 /* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */
556 while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
557 ofs += 4;
558
559 if (ofs == max_ofs) {
560 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
561 if (jffs2_cleanmarker_oob(c)) {
562 /* scan oob, take care of cleanmarker */
563 int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
564 D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
565 switch (ret) {
566 case 0: return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
567 case 1: return BLK_STATE_ALLDIRTY;
568 default: return ret;
569 }
570 }
571 #endif
572 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
573 if (c->cleanmarker_size == 0)
574 return BLK_STATE_CLEANMARKER; /* don't bother with re-erase */
575 else
576 return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
577 }
578 if (ofs) {
579 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
580 jeb->offset + ofs));
581 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
582 return err;
583 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
584 return err;
585 }
586
587 /* Now ofs is a complete physical flash offset as it always was... */
588 ofs += jeb->offset;
589
590 noise = 10;
591
592 dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
593
594 scan_more:
595 while(ofs < jeb->offset + c->sector_size) {
596
597 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
598
599 /* Make sure there are node refs available for use */
600 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
601 if (err)
602 return err;
603
604 cond_resched();
605
606 if (ofs & 3) {
607 printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
608 ofs = PAD(ofs);
609 continue;
610 }
611 if (ofs == prevofs) {
612 printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
613 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
614 return err;
615 ofs += 4;
616 continue;
617 }
618 prevofs = ofs;
619
620 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
621 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),
622 jeb->offset, c->sector_size, ofs, sizeof(*node)));
623 if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
624 return err;
625 break;
626 }
627
628 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
629 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
630 D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
631 sizeof(struct jffs2_unknown_node), buf_len, ofs));
632 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
633 if (err)
634 return err;
635 buf_ofs = ofs;
636 }
637
638 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
639
640 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
641 uint32_t inbuf_ofs;
642 uint32_t empty_start, scan_end;
643
644 empty_start = ofs;
645 ofs += 4;
646 scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);
647
648 D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
649 more_empty:
650 inbuf_ofs = ofs - buf_ofs;
651 while (inbuf_ofs < scan_end) {
652 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {
653 printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
654 empty_start, ofs);
655 if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
656 return err;
657 goto scan_more;
658 }
659
660 inbuf_ofs+=4;
661 ofs += 4;
662 }
663 /* Ran off end. */
664 D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
665
666 /* If we're only checking the beginning of a block with a cleanmarker,
667 bail now */
668 if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
669 c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
670 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
671 return BLK_STATE_CLEANMARKER;
672 }
673 if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
674 scan_end = buf_len;
675 goto more_empty;
676 }
677
678 /* See how much more there is to read in this eraseblock... */
679 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
680 if (!buf_len) {
681 /* No more to read. Break out of main loop without marking
682 this range of empty space as dirty (because it's not) */
683 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
684 empty_start));
685 break;
686 }
687 /* point never reaches here */
688 scan_end = buf_len;
689 D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
690 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
691 if (err)
692 return err;
693 buf_ofs = ofs;
694 goto more_empty;
695 }
696
697 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
698 printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
699 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
700 return err;
701 ofs += 4;
702 continue;
703 }
704 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
705 D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
706 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
707 return err;
708 ofs += 4;
709 continue;
710 }
711 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
712 printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
713 printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
714 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
715 return err;
716 ofs += 4;
717 continue;
718 }
719 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
720 /* OK. We're out of possibilities. Whinge and move on */
721 noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
722 JFFS2_MAGIC_BITMASK, ofs,
723 je16_to_cpu(node->magic));
724 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
725 return err;
726 ofs += 4;
727 continue;
728 }
729 /* We seem to have a node of sorts. Check the CRC */
730 crcnode.magic = node->magic;
731 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
732 crcnode.totlen = node->totlen;
733 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
734
735 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
736 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",
737 ofs, je16_to_cpu(node->magic),
738 je16_to_cpu(node->nodetype),
739 je32_to_cpu(node->totlen),
740 je32_to_cpu(node->hdr_crc),
741 hdr_crc);
742 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
743 return err;
744 ofs += 4;
745 continue;
746 }
747
748 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) {
749 /* Eep. Node goes over the end of the erase block. */
750 printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
751 ofs, je32_to_cpu(node->totlen));
752 printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
753 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
754 return err;
755 ofs += 4;
756 continue;
757 }
758
759 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
760 /* Wheee. This is an obsoleted node */
761 D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
762 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
763 return err;
764 ofs += PAD(je32_to_cpu(node->totlen));
765 continue;
766 }
767
768 switch(je16_to_cpu(node->nodetype)) {
769 case JFFS2_NODETYPE_INODE:
770 if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
771 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
772 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
773 sizeof(struct jffs2_raw_inode), buf_len, ofs));
774 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
775 if (err)
776 return err;
777 buf_ofs = ofs;
778 node = (void *)buf;
779 }
780 err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
781 if (err) return err;
782 ofs += PAD(je32_to_cpu(node->totlen));
783 break;
784
785 case JFFS2_NODETYPE_DIRENT:
786 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
787 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
788 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
789 je32_to_cpu(node->totlen), buf_len, ofs));
790 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
791 if (err)
792 return err;
793 buf_ofs = ofs;
794 node = (void *)buf;
795 }
796 err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
797 if (err) return err;
798 ofs += PAD(je32_to_cpu(node->totlen));
799 break;
800
801 #ifdef CONFIG_JFFS2_FS_XATTR
802 case JFFS2_NODETYPE_XATTR:
803 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
804 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
805 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
806 " left to end of buf. Reading 0x%x at 0x%08x\n",
807 je32_to_cpu(node->totlen), buf_len, ofs));
808 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
809 if (err)
810 return err;
811 buf_ofs = ofs;
812 node = (void *)buf;
813 }
814 err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
815 if (err)
816 return err;
817 ofs += PAD(je32_to_cpu(node->totlen));
818 break;
819 case JFFS2_NODETYPE_XREF:
820 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
821 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
822 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
823 " left to end of buf. Reading 0x%x at 0x%08x\n",
824 je32_to_cpu(node->totlen), buf_len, ofs));
825 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
826 if (err)
827 return err;
828 buf_ofs = ofs;
829 node = (void *)buf;
830 }
831 err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
832 if (err)
833 return err;
834 ofs += PAD(je32_to_cpu(node->totlen));
835 break;
836 #endif /* CONFIG_JFFS2_FS_XATTR */
837
838 case JFFS2_NODETYPE_CLEANMARKER:
839 D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
840 if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
841 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
842 ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
843 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
844 return err;
845 ofs += PAD(sizeof(struct jffs2_unknown_node));
846 } else if (jeb->first_node) {
847 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
848 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
849 return err;
850 ofs += PAD(sizeof(struct jffs2_unknown_node));
851 } else {
852 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
853
854 ofs += PAD(c->cleanmarker_size);
855 }
856 break;
857
858 case JFFS2_NODETYPE_PADDING:
859 if (jffs2_sum_active())
860 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
861 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
862 return err;
863 ofs += PAD(je32_to_cpu(node->totlen));
864 break;
865
866 default:
867 switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
868 case JFFS2_FEATURE_ROCOMPAT:
869 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
870 c->flags |= JFFS2_SB_FLAG_RO;
871 if (!(jffs2_is_readonly(c)))
872 return -EROFS;
873 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
874 return err;
875 ofs += PAD(je32_to_cpu(node->totlen));
876 break;
877
878 case JFFS2_FEATURE_INCOMPAT:
879 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
880 return -EINVAL;
881
882 case JFFS2_FEATURE_RWCOMPAT_DELETE:
883 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
884 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
885 return err;
886 ofs += PAD(je32_to_cpu(node->totlen));
887 break;
888
889 case JFFS2_FEATURE_RWCOMPAT_COPY: {
890 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
891
892 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
893
894 /* We can't summarise nodes we don't grok */
895 jffs2_sum_disable_collecting(s);
896 ofs += PAD(je32_to_cpu(node->totlen));
897 break;
898 }
899 }
900 }
901 }
902
903 if (jffs2_sum_active()) {
904 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
905 dbg_summary("There is not enough space for "
906 "summary information, disabling for this jeb!\n");
907 jffs2_sum_disable_collecting(s);
908 }
909 }
910
911 D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
912 jeb->offset,jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size, jeb->wasted_size));
913
914 /* mark_node_obsolete can add to wasted !! */
915 if (jeb->wasted_size) {
916 jeb->dirty_size += jeb->wasted_size;
917 c->dirty_size += jeb->wasted_size;
918 c->wasted_size -= jeb->wasted_size;
919 jeb->wasted_size = 0;
920 }
921
922 return jffs2_scan_classify_jeb(c, jeb);
923 }
924
925 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
926 {
927 struct jffs2_inode_cache *ic;
928
929 ic = jffs2_get_ino_cache(c, ino);
930 if (ic)
931 return ic;
932
933 if (ino > c->highest_ino)
934 c->highest_ino = ino;
935
936 ic = jffs2_alloc_inode_cache();
937 if (!ic) {
938 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
939 return NULL;
940 }
941 memset(ic, 0, sizeof(*ic));
942
943 ic->ino = ino;
944 ic->nodes = (void *)ic;
945 jffs2_add_ino_cache(c, ic);
946 if (ino == 1)
947 ic->pino_nlink = 1;
948 return ic;
949 }
950
951 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
952 struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
953 {
954 struct jffs2_inode_cache *ic;
955 uint32_t crc, ino = je32_to_cpu(ri->ino);
956
957 D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
958
959 /* We do very little here now. Just check the ino# to which we should attribute
960 this node; we can do all the CRC checking etc. later. There's a tradeoff here --
961 we used to scan the flash once only, reading everything we want from it into
962 memory, then building all our in-core data structures and freeing the extra
963 information. Now we allow the first part of the mount to complete a lot quicker,
964 but we have to go _back_ to the flash in order to finish the CRC checking, etc.
965 Which means that the _full_ amount of time to get to proper write mode with GC
966 operational may actually be _longer_ than before. Sucks to be me. */
967
968 /* Check the node CRC in any case. */
969 crc = crc32(0, ri, sizeof(*ri)-8);
970 if (crc != je32_to_cpu(ri->node_crc)) {
971 printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on "
972 "node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
973 ofs, je32_to_cpu(ri->node_crc), crc);
974 /*
975 * We believe totlen because the CRC on the node
976 * _header_ was OK, just the node itself failed.
977 */
978 return jffs2_scan_dirty_space(c, jeb,
979 PAD(je32_to_cpu(ri->totlen)));
980 }
981
982 ic = jffs2_get_ino_cache(c, ino);
983 if (!ic) {
984 ic = jffs2_scan_make_ino_cache(c, ino);
985 if (!ic)
986 return -ENOMEM;
987 }
988
989 /* Wheee. It worked */
990 jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
991
992 D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
993 je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
994 je32_to_cpu(ri->offset),
995 je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
996
997 pseudo_random += je32_to_cpu(ri->version);
998
999 if (jffs2_sum_active()) {
1000 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
1001 }
1002
1003 return 0;
1004 }
1005
1006 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1007 struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
1008 {
1009 struct jffs2_full_dirent *fd;
1010 struct jffs2_inode_cache *ic;
1011 uint32_t checkedlen;
1012 uint32_t crc;
1013 int err;
1014
1015 D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
1016
1017 /* We don't get here unless the node is still valid, so we don't have to
1018 mask in the ACCURATE bit any more. */
1019 crc = crc32(0, rd, sizeof(*rd)-8);
1020
1021 if (crc != je32_to_cpu(rd->node_crc)) {
1022 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1023 ofs, je32_to_cpu(rd->node_crc), crc);
1024 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1025 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1026 return err;
1027 return 0;
1028 }
1029
1030 pseudo_random += je32_to_cpu(rd->version);
1031
1032 /* Should never happen. Did. (OLPC trac #4184)*/
1033 checkedlen = strnlen(rd->name, rd->nsize);
1034 if (checkedlen < rd->nsize) {
1035 printk(KERN_ERR "Dirent at %08x has zeroes in name. Truncating to %d chars\n",
1036 ofs, checkedlen);
1037 }
1038 fd = jffs2_alloc_full_dirent(checkedlen+1);
1039 if (!fd) {
1040 return -ENOMEM;
1041 }
1042 memcpy(&fd->name, rd->name, checkedlen);
1043 fd->name[checkedlen] = 0;
1044
1045 crc = crc32(0, fd->name, rd->nsize);
1046 if (crc != je32_to_cpu(rd->name_crc)) {
1047 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1048 ofs, je32_to_cpu(rd->name_crc), crc);
1049 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
1050 jffs2_free_full_dirent(fd);
1051 /* FIXME: Why do we believe totlen? */
1052 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1053 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1054 return err;
1055 return 0;
1056 }
1057 ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1058 if (!ic) {
1059 jffs2_free_full_dirent(fd);
1060 return -ENOMEM;
1061 }
1062
1063 fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
1064 PAD(je32_to_cpu(rd->totlen)), ic);
1065
1066 fd->next = NULL;
1067 fd->version = je32_to_cpu(rd->version);
1068 fd->ino = je32_to_cpu(rd->ino);
1069 fd->nhash = full_name_hash(fd->name, checkedlen);
1070 fd->type = rd->type;
1071 jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1072
1073 if (jffs2_sum_active()) {
1074 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1075 }
1076
1077 return 0;
1078 }
1079
1080 static int count_list(struct list_head *l)
1081 {
1082 uint32_t count = 0;
1083 struct list_head *tmp;
1084
1085 list_for_each(tmp, l) {
1086 count++;
1087 }
1088 return count;
1089 }
1090
1091 /* Note: This breaks if list_empty(head). I don't care. You
1092 might, if you copy this code and use it elsewhere :) */
1093 static void rotate_list(struct list_head *head, uint32_t count)
1094 {
1095 struct list_head *n = head->next;
1096
1097 list_del(head);
1098 while(count--) {
1099 n = n->next;
1100 }
1101 list_add(head, n);
1102 }
1103
1104 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1105 {
1106 uint32_t x;
1107 uint32_t rotateby;
1108
1109 x = count_list(&c->clean_list);
1110 if (x) {
1111 rotateby = pseudo_random % x;
1112 rotate_list((&c->clean_list), rotateby);
1113 }
1114
1115 x = count_list(&c->very_dirty_list);
1116 if (x) {
1117 rotateby = pseudo_random % x;
1118 rotate_list((&c->very_dirty_list), rotateby);
1119 }
1120
1121 x = count_list(&c->dirty_list);
1122 if (x) {
1123 rotateby = pseudo_random % x;
1124 rotate_list((&c->dirty_list), rotateby);
1125 }
1126
1127 x = count_list(&c->erasable_list);
1128 if (x) {
1129 rotateby = pseudo_random % x;
1130 rotate_list((&c->erasable_list), rotateby);
1131 }
1132
1133 if (c->nr_erasing_blocks) {
1134 rotateby = pseudo_random % c->nr_erasing_blocks;
1135 rotate_list((&c->erase_pending_list), rotateby);
1136 }
1137
1138 if (c->nr_free_blocks) {
1139 rotateby = pseudo_random % c->nr_free_blocks;
1140 rotate_list((&c->free_list), rotateby);
1141 }
1142 }