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md/linear: avoid corrupting structure while waiting for rcu_free to complete.
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / jffs2 / scan.c
blob8d8cd3419d02a75a7b0a7336da995a430324448b
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 = c->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 c->mtd->unpoint(c->mtd, 0, pointlen);
106 flashbuf = NULL;
107 }
108 if (ret)
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 c->mtd->unpoint(c->mtd, 0, c->mtd->size);
277 #endif
278 if (s)
279 kfree(s);
280
281 return ret;
282 }
283
284 static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf,
285 uint32_t ofs, uint32_t len)
286 {
287 int ret;
288 size_t retlen;
289
290 ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
291 if (ret) {
292 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
293 return ret;
294 }
295 if (retlen < len) {
296 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
297 return -EIO;
298 }
299 return 0;
300 }
301
302 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
303 {
304 if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
305 && (!jeb->first_node || !ref_next(jeb->first_node)) )
306 return BLK_STATE_CLEANMARKER;
307
308 /* move blocks with max 4 byte dirty space to cleanlist */
309 else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
310 c->dirty_size -= jeb->dirty_size;
311 c->wasted_size += jeb->dirty_size;
312 jeb->wasted_size += jeb->dirty_size;
313 jeb->dirty_size = 0;
314 return BLK_STATE_CLEAN;
315 } else if (jeb->used_size || jeb->unchecked_size)
316 return BLK_STATE_PARTDIRTY;
317 else
318 return BLK_STATE_ALLDIRTY;
319 }
320
321 #ifdef CONFIG_JFFS2_FS_XATTR
322 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
323 struct jffs2_raw_xattr *rx, uint32_t ofs,
324 struct jffs2_summary *s)
325 {
326 struct jffs2_xattr_datum *xd;
327 uint32_t xid, version, totlen, crc;
328 int err;
329
330 crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
331 if (crc != je32_to_cpu(rx->node_crc)) {
332 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
333 ofs, je32_to_cpu(rx->node_crc), crc);
334 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
335 return err;
336 return 0;
337 }
338
339 xid = je32_to_cpu(rx->xid);
340 version = je32_to_cpu(rx->version);
341
342 totlen = PAD(sizeof(struct jffs2_raw_xattr)
343 + rx->name_len + 1 + je16_to_cpu(rx->value_len));
344 if (totlen != je32_to_cpu(rx->totlen)) {
345 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
346 ofs, je32_to_cpu(rx->totlen), totlen);
347 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
348 return err;
349 return 0;
350 }
351
352 xd = jffs2_setup_xattr_datum(c, xid, version);
353 if (IS_ERR(xd))
354 return PTR_ERR(xd);
355
356 if (xd->version > version) {
357 struct jffs2_raw_node_ref *raw
358 = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
359 raw->next_in_ino = xd->node->next_in_ino;
360 xd->node->next_in_ino = raw;
361 } else {
362 xd->version = version;
363 xd->xprefix = rx->xprefix;
364 xd->name_len = rx->name_len;
365 xd->value_len = je16_to_cpu(rx->value_len);
366 xd->data_crc = je32_to_cpu(rx->data_crc);
367
368 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
369 }
370
371 if (jffs2_sum_active())
372 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
373 dbg_xattr("scaning xdatum at %#08x (xid=%u, version=%u)\n",
374 ofs, xd->xid, xd->version);
375 return 0;
376 }
377
378 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
379 struct jffs2_raw_xref *rr, uint32_t ofs,
380 struct jffs2_summary *s)
381 {
382 struct jffs2_xattr_ref *ref;
383 uint32_t crc;
384 int err;
385
386 crc = crc32(0, rr, sizeof(*rr) - 4);
387 if (crc != je32_to_cpu(rr->node_crc)) {
388 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
389 ofs, je32_to_cpu(rr->node_crc), crc);
390 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
391 return err;
392 return 0;
393 }
394
395 if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
396 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n",
397 ofs, je32_to_cpu(rr->totlen),
398 PAD(sizeof(struct jffs2_raw_xref)));
399 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
400 return err;
401 return 0;
402 }
403
404 ref = jffs2_alloc_xattr_ref();
405 if (!ref)
406 return -ENOMEM;
407
408 /* BEFORE jffs2_build_xattr_subsystem() called,
409 * and AFTER xattr_ref is marked as a dead xref,
410 * ref->xid is used to store 32bit xid, xd is not used
411 * ref->ino is used to store 32bit inode-number, ic is not used
412 * Thoes variables are declared as union, thus using those
413 * are exclusive. In a similar way, ref->next is temporarily
414 * used to chain all xattr_ref object. It's re-chained to
415 * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
416 */
417 ref->ino = je32_to_cpu(rr->ino);
418 ref->xid = je32_to_cpu(rr->xid);
419 ref->xseqno = je32_to_cpu(rr->xseqno);
420 if (ref->xseqno > c->highest_xseqno)
421 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
422 ref->next = c->xref_temp;
423 c->xref_temp = ref;
424
425 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);
426
427 if (jffs2_sum_active())
428 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
429 dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
430 ofs, ref->xid, ref->ino);
431 return 0;
432 }
433 #endif
434
435 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
436 the flash, XIP-style */
437 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
438 unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
439 struct jffs2_unknown_node *node;
440 struct jffs2_unknown_node crcnode;
441 uint32_t ofs, prevofs, max_ofs;
442 uint32_t hdr_crc, buf_ofs, buf_len;
443 int err;
444 int noise = 0;
445
446
447 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
448 int cleanmarkerfound = 0;
449 #endif
450
451 ofs = jeb->offset;
452 prevofs = jeb->offset - 1;
453
454 D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
455
456 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
457 if (jffs2_cleanmarker_oob(c)) {
458 int ret;
459
460 if (c->mtd->block_isbad(c->mtd, jeb->offset))
461 return BLK_STATE_BADBLOCK;
462
463 ret = jffs2_check_nand_cleanmarker(c, jeb);
464 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
465
466 /* Even if it's not found, we still scan to see
467 if the block is empty. We use this information
468 to decide whether to erase it or not. */
469 switch (ret) {
470 case 0: cleanmarkerfound = 1; break;
471 case 1: break;
472 default: return ret;
473 }
474 }
475 #endif
476
477 if (jffs2_sum_active()) {
478 struct jffs2_sum_marker *sm;
479 void *sumptr = NULL;
480 uint32_t sumlen;
481
482 if (!buf_size) {
483 /* XIP case. Just look, point at the summary if it's there */
484 sm = (void *)buf + c->sector_size - sizeof(*sm);
485 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
486 sumptr = buf + je32_to_cpu(sm->offset);
487 sumlen = c->sector_size - je32_to_cpu(sm->offset);
488 }
489 } else {
490 /* If NAND flash, read a whole page of it. Else just the end */
491 if (c->wbuf_pagesize)
492 buf_len = c->wbuf_pagesize;
493 else
494 buf_len = sizeof(*sm);
495
496 /* Read as much as we want into the _end_ of the preallocated buffer */
497 err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
498 jeb->offset + c->sector_size - buf_len,
499 buf_len);
500 if (err)
501 return err;
502
503 sm = (void *)buf + buf_size - sizeof(*sm);
504 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
505 sumlen = c->sector_size - je32_to_cpu(sm->offset);
506 sumptr = buf + buf_size - sumlen;
507
508 /* Now, make sure the summary itself is available */
509 if (sumlen > buf_size) {
510 /* Need to kmalloc for this. */
511 sumptr = kmalloc(sumlen, GFP_KERNEL);
512 if (!sumptr)
513 return -ENOMEM;
514 memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
515 }
516 if (buf_len < sumlen) {
517 /* Need to read more so that the entire summary node is present */
518 err = jffs2_fill_scan_buf(c, sumptr,
519 jeb->offset + c->sector_size - sumlen,
520 sumlen - buf_len);
521 if (err)
522 return err;
523 }
524 }
525
526 }
527
528 if (sumptr) {
529 err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
530
531 if (buf_size && sumlen > buf_size)
532 kfree(sumptr);
533 /* If it returns with a real error, bail.
534 If it returns positive, that's a block classification
535 (i.e. BLK_STATE_xxx) so return that too.
536 If it returns zero, fall through to full scan. */
537 if (err)
538 return err;
539 }
540 }
541
542 buf_ofs = jeb->offset;
543
544 if (!buf_size) {
545 /* This is the XIP case -- we're reading _directly_ from the flash chip */
546 buf_len = c->sector_size;
547 } else {
548 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
549 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
550 if (err)
551 return err;
552 }
553
554 /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
555 ofs = 0;
556 max_ofs = EMPTY_SCAN_SIZE(c->sector_size);
557 /* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */
558 while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
559 ofs += 4;
560
561 if (ofs == max_ofs) {
562 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
563 if (jffs2_cleanmarker_oob(c)) {
564 /* scan oob, take care of cleanmarker */
565 int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
566 D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
567 switch (ret) {
568 case 0: return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
569 case 1: return BLK_STATE_ALLDIRTY;
570 default: return ret;
571 }
572 }
573 #endif
574 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
575 if (c->cleanmarker_size == 0)
576 return BLK_STATE_CLEANMARKER; /* don't bother with re-erase */
577 else
578 return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
579 }
580 if (ofs) {
581 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
582 jeb->offset + ofs));
583 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
584 return err;
585 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
586 return err;
587 }
588
589 /* Now ofs is a complete physical flash offset as it always was... */
590 ofs += jeb->offset;
591
592 noise = 10;
593
594 dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
595
596 scan_more:
597 while(ofs < jeb->offset + c->sector_size) {
598
599 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
600
601 /* Make sure there are node refs available for use */
602 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
603 if (err)
604 return err;
605
606 cond_resched();
607
608 if (ofs & 3) {
609 printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
610 ofs = PAD(ofs);
611 continue;
612 }
613 if (ofs == prevofs) {
614 printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
615 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
616 return err;
617 ofs += 4;
618 continue;
619 }
620 prevofs = ofs;
621
622 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
623 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),
624 jeb->offset, c->sector_size, ofs, sizeof(*node)));
625 if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
626 return err;
627 break;
628 }
629
630 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
631 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
632 D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
633 sizeof(struct jffs2_unknown_node), buf_len, ofs));
634 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
635 if (err)
636 return err;
637 buf_ofs = ofs;
638 }
639
640 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
641
642 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
643 uint32_t inbuf_ofs;
644 uint32_t empty_start, scan_end;
645
646 empty_start = ofs;
647 ofs += 4;
648 scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);
649
650 D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
651 more_empty:
652 inbuf_ofs = ofs - buf_ofs;
653 while (inbuf_ofs < scan_end) {
654 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {
655 printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
656 empty_start, ofs);
657 if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
658 return err;
659 goto scan_more;
660 }
661
662 inbuf_ofs+=4;
663 ofs += 4;
664 }
665 /* Ran off end. */
666 D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
667
668 /* If we're only checking the beginning of a block with a cleanmarker,
669 bail now */
670 if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
671 c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
672 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
673 return BLK_STATE_CLEANMARKER;
674 }
675 if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
676 scan_end = buf_len;
677 goto more_empty;
678 }
679
680 /* See how much more there is to read in this eraseblock... */
681 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
682 if (!buf_len) {
683 /* No more to read. Break out of main loop without marking
684 this range of empty space as dirty (because it's not) */
685 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
686 empty_start));
687 break;
688 }
689 /* point never reaches here */
690 scan_end = buf_len;
691 D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
692 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
693 if (err)
694 return err;
695 buf_ofs = ofs;
696 goto more_empty;
697 }
698
699 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
700 printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
701 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
702 return err;
703 ofs += 4;
704 continue;
705 }
706 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
707 D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
708 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
709 return err;
710 ofs += 4;
711 continue;
712 }
713 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
714 printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
715 printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
716 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
717 return err;
718 ofs += 4;
719 continue;
720 }
721 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
722 /* OK. We're out of possibilities. Whinge and move on */
723 noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
724 JFFS2_MAGIC_BITMASK, ofs,
725 je16_to_cpu(node->magic));
726 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
727 return err;
728 ofs += 4;
729 continue;
730 }
731 /* We seem to have a node of sorts. Check the CRC */
732 crcnode.magic = node->magic;
733 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
734 crcnode.totlen = node->totlen;
735 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
736
737 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
738 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",
739 ofs, je16_to_cpu(node->magic),
740 je16_to_cpu(node->nodetype),
741 je32_to_cpu(node->totlen),
742 je32_to_cpu(node->hdr_crc),
743 hdr_crc);
744 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
745 return err;
746 ofs += 4;
747 continue;
748 }
749
750 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) {
751 /* Eep. Node goes over the end of the erase block. */
752 printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
753 ofs, je32_to_cpu(node->totlen));
754 printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
755 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
756 return err;
757 ofs += 4;
758 continue;
759 }
760
761 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
762 /* Wheee. This is an obsoleted node */
763 D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
764 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
765 return err;
766 ofs += PAD(je32_to_cpu(node->totlen));
767 continue;
768 }
769
770 switch(je16_to_cpu(node->nodetype)) {
771 case JFFS2_NODETYPE_INODE:
772 if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
773 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
774 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
775 sizeof(struct jffs2_raw_inode), buf_len, ofs));
776 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
777 if (err)
778 return err;
779 buf_ofs = ofs;
780 node = (void *)buf;
781 }
782 err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
783 if (err) return err;
784 ofs += PAD(je32_to_cpu(node->totlen));
785 break;
786
787 case JFFS2_NODETYPE_DIRENT:
788 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
789 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
790 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
791 je32_to_cpu(node->totlen), buf_len, ofs));
792 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
793 if (err)
794 return err;
795 buf_ofs = ofs;
796 node = (void *)buf;
797 }
798 err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
799 if (err) return err;
800 ofs += PAD(je32_to_cpu(node->totlen));
801 break;
802
803 #ifdef CONFIG_JFFS2_FS_XATTR
804 case JFFS2_NODETYPE_XATTR:
805 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
806 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
807 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)"
808 " left to end of buf. Reading 0x%x at 0x%08x\n",
809 je32_to_cpu(node->totlen), buf_len, ofs));
810 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
811 if (err)
812 return err;
813 buf_ofs = ofs;
814 node = (void *)buf;
815 }
816 err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
817 if (err)
818 return err;
819 ofs += PAD(je32_to_cpu(node->totlen));
820 break;
821 case JFFS2_NODETYPE_XREF:
822 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
823 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
824 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)"
825 " left to end of buf. Reading 0x%x at 0x%08x\n",
826 je32_to_cpu(node->totlen), buf_len, ofs));
827 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
828 if (err)
829 return err;
830 buf_ofs = ofs;
831 node = (void *)buf;
832 }
833 err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
834 if (err)
835 return err;
836 ofs += PAD(je32_to_cpu(node->totlen));
837 break;
838 #endif /* CONFIG_JFFS2_FS_XATTR */
839
840 case JFFS2_NODETYPE_CLEANMARKER:
841 D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
842 if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
843 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
844 ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
845 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
846 return err;
847 ofs += PAD(sizeof(struct jffs2_unknown_node));
848 } else if (jeb->first_node) {
849 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
850 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
851 return err;
852 ofs += PAD(sizeof(struct jffs2_unknown_node));
853 } else {
854 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
855
856 ofs += PAD(c->cleanmarker_size);
857 }
858 break;
859
860 case JFFS2_NODETYPE_PADDING:
861 if (jffs2_sum_active())
862 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
863 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
864 return err;
865 ofs += PAD(je32_to_cpu(node->totlen));
866 break;
867
868 default:
869 switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
870 case JFFS2_FEATURE_ROCOMPAT:
871 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
872 c->flags |= JFFS2_SB_FLAG_RO;
873 if (!(jffs2_is_readonly(c)))
874 return -EROFS;
875 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
876 return err;
877 ofs += PAD(je32_to_cpu(node->totlen));
878 break;
879
880 case JFFS2_FEATURE_INCOMPAT:
881 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
882 return -EINVAL;
883
884 case JFFS2_FEATURE_RWCOMPAT_DELETE:
885 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
886 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
887 return err;
888 ofs += PAD(je32_to_cpu(node->totlen));
889 break;
890
891 case JFFS2_FEATURE_RWCOMPAT_COPY: {
892 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
893
894 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
895
896 /* We can't summarise nodes we don't grok */
897 jffs2_sum_disable_collecting(s);
898 ofs += PAD(je32_to_cpu(node->totlen));
899 break;
900 }
901 }
902 }
903 }
904
905 if (jffs2_sum_active()) {
906 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
907 dbg_summary("There is not enough space for "
908 "summary information, disabling for this jeb!\n");
909 jffs2_sum_disable_collecting(s);
910 }
911 }
912
913 D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
914 jeb->offset,jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size, jeb->wasted_size));
915
916 /* mark_node_obsolete can add to wasted !! */
917 if (jeb->wasted_size) {
918 jeb->dirty_size += jeb->wasted_size;
919 c->dirty_size += jeb->wasted_size;
920 c->wasted_size -= jeb->wasted_size;
921 jeb->wasted_size = 0;
922 }
923
924 return jffs2_scan_classify_jeb(c, jeb);
925 }
926
927 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
928 {
929 struct jffs2_inode_cache *ic;
930
931 ic = jffs2_get_ino_cache(c, ino);
932 if (ic)
933 return ic;
934
935 if (ino > c->highest_ino)
936 c->highest_ino = ino;
937
938 ic = jffs2_alloc_inode_cache();
939 if (!ic) {
940 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
941 return NULL;
942 }
943 memset(ic, 0, sizeof(*ic));
944
945 ic->ino = ino;
946 ic->nodes = (void *)ic;
947 jffs2_add_ino_cache(c, ic);
948 if (ino == 1)
949 ic->pino_nlink = 1;
950 return ic;
951 }
952
953 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
954 struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
955 {
956 struct jffs2_inode_cache *ic;
957 uint32_t crc, ino = je32_to_cpu(ri->ino);
958
959 D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
960
961 /* We do very little here now. Just check the ino# to which we should attribute
962 this node; we can do all the CRC checking etc. later. There's a tradeoff here --
963 we used to scan the flash once only, reading everything we want from it into
964 memory, then building all our in-core data structures and freeing the extra
965 information. Now we allow the first part of the mount to complete a lot quicker,
966 but we have to go _back_ to the flash in order to finish the CRC checking, etc.
967 Which means that the _full_ amount of time to get to proper write mode with GC
968 operational may actually be _longer_ than before. Sucks to be me. */
969
970 /* Check the node CRC in any case. */
971 crc = crc32(0, ri, sizeof(*ri)-8);
972 if (crc != je32_to_cpu(ri->node_crc)) {
973 printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on "
974 "node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
975 ofs, je32_to_cpu(ri->node_crc), crc);
976 /*
977 * We believe totlen because the CRC on the node
978 * _header_ was OK, just the node itself failed.
979 */
980 return jffs2_scan_dirty_space(c, jeb,
981 PAD(je32_to_cpu(ri->totlen)));
982 }
983
984 ic = jffs2_get_ino_cache(c, ino);
985 if (!ic) {
986 ic = jffs2_scan_make_ino_cache(c, ino);
987 if (!ic)
988 return -ENOMEM;
989 }
990
991 /* Wheee. It worked */
992 jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
993
994 D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
995 je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
996 je32_to_cpu(ri->offset),
997 je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
998
999 pseudo_random += je32_to_cpu(ri->version);
1000
1001 if (jffs2_sum_active()) {
1002 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
1003 }
1004
1005 return 0;
1006 }
1007
1008 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1009 struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
1010 {
1011 struct jffs2_full_dirent *fd;
1012 struct jffs2_inode_cache *ic;
1013 uint32_t checkedlen;
1014 uint32_t crc;
1015 int err;
1016
1017 D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
1018
1019 /* We don't get here unless the node is still valid, so we don't have to
1020 mask in the ACCURATE bit any more. */
1021 crc = crc32(0, rd, sizeof(*rd)-8);
1022
1023 if (crc != je32_to_cpu(rd->node_crc)) {
1024 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1025 ofs, je32_to_cpu(rd->node_crc), crc);
1026 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1027 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1028 return err;
1029 return 0;
1030 }
1031
1032 pseudo_random += je32_to_cpu(rd->version);
1033
1034 /* Should never happen. Did. (OLPC trac #4184)*/
1035 checkedlen = strnlen(rd->name, rd->nsize);
1036 if (checkedlen < rd->nsize) {
1037 printk(KERN_ERR "Dirent at %08x has zeroes in name. Truncating to %d chars\n",
1038 ofs, checkedlen);
1039 }
1040 fd = jffs2_alloc_full_dirent(checkedlen+1);
1041 if (!fd) {
1042 return -ENOMEM;
1043 }
1044 memcpy(&fd->name, rd->name, checkedlen);
1045 fd->name[checkedlen] = 0;
1046
1047 crc = crc32(0, fd->name, rd->nsize);
1048 if (crc != je32_to_cpu(rd->name_crc)) {
1049 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1050 ofs, je32_to_cpu(rd->name_crc), crc);
1051 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
1052 jffs2_free_full_dirent(fd);
1053 /* FIXME: Why do we believe totlen? */
1054 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1055 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1056 return err;
1057 return 0;
1058 }
1059 ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1060 if (!ic) {
1061 jffs2_free_full_dirent(fd);
1062 return -ENOMEM;
1063 }
1064
1065 fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
1066 PAD(je32_to_cpu(rd->totlen)), ic);
1067
1068 fd->next = NULL;
1069 fd->version = je32_to_cpu(rd->version);
1070 fd->ino = je32_to_cpu(rd->ino);
1071 fd->nhash = full_name_hash(fd->name, checkedlen);
1072 fd->type = rd->type;
1073 jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1074
1075 if (jffs2_sum_active()) {
1076 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1077 }
1078
1079 return 0;
1080 }
1081
1082 static int count_list(struct list_head *l)
1083 {
1084 uint32_t count = 0;
1085 struct list_head *tmp;
1086
1087 list_for_each(tmp, l) {
1088 count++;
1089 }
1090 return count;
1091 }
1092
1093 /* Note: This breaks if list_empty(head). I don't care. You
1094 might, if you copy this code and use it elsewhere :) */
1095 static void rotate_list(struct list_head *head, uint32_t count)
1096 {
1097 struct list_head *n = head->next;
1098
1099 list_del(head);
1100 while(count--) {
1101 n = n->next;
1102 }
1103 list_add(head, n);
1104 }
1105
1106 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1107 {
1108 uint32_t x;
1109 uint32_t rotateby;
1110
1111 x = count_list(&c->clean_list);
1112 if (x) {
1113 rotateby = pseudo_random % x;
1114 rotate_list((&c->clean_list), rotateby);
1115 }
1116
1117 x = count_list(&c->very_dirty_list);
1118 if (x) {
1119 rotateby = pseudo_random % x;
1120 rotate_list((&c->very_dirty_list), rotateby);
1121 }
1122
1123 x = count_list(&c->dirty_list);
1124 if (x) {
1125 rotateby = pseudo_random % x;
1126 rotate_list((&c->dirty_list), rotateby);
1127 }
1128
1129 x = count_list(&c->erasable_list);
1130 if (x) {
1131 rotateby = pseudo_random % x;
1132 rotate_list((&c->erasable_list), rotateby);
1133 }
1134
1135 if (c->nr_erasing_blocks) {
1136 rotateby = pseudo_random % c->nr_erasing_blocks;
1137 rotate_list((&c->erase_pending_list), rotateby);
1138 }
1139
1140 if (c->nr_free_blocks) {
1141 rotateby = pseudo_random % c->nr_free_blocks;
1142 rotate_list((&c->free_list), rotateby);
1143 }
1144 }
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree