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Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm...
[linux-2.6.git] / fs / jffs2 / scan.c
blob7654e87b042869ef43aff269a10e88a4088d59c3
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/kernel.h>
15 #include <linux/sched.h>
16 #include <linux/slab.h>
17 #include <linux/mtd/mtd.h>
18 #include <linux/pagemap.h>
19 #include <linux/crc32.h>
20 #include <linux/compiler.h>
21 #include "nodelist.h"
22 #include "summary.h"
23 #include "debug.h"
24
25 #define DEFAULT_EMPTY_SCAN_SIZE 256
26
27 #define noisy_printk(noise, fmt, ...) \
28 do { \
29 if (*(noise)) { \
30 pr_notice(fmt, ##__VA_ARGS__); \
31 (*(noise))--; \
32 if (!(*(noise))) \
33 pr_notice("Further such events for this erase block will not be printed\n"); \
34 } \
35 } while (0)
36
37 static uint32_t pseudo_random;
38
39 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
40 unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);
41
42 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
43 * Returning an error will abort the mount - bad checksums etc. should just mark the space
44 * as dirty.
45 */
46 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
47 struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);
48 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
49 struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);
50
51 static inline int min_free(struct jffs2_sb_info *c)
52 {
53 uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
54 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
55 if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
56 return c->wbuf_pagesize;
57 #endif
58 return min;
59
60 }
61
62 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
63 if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
64 return sector_size;
65 else
66 return DEFAULT_EMPTY_SCAN_SIZE;
67 }
68
69 static int file_dirty(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
70 {
71 int ret;
72
73 if ((ret = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
74 return ret;
75 if ((ret = jffs2_scan_dirty_space(c, jeb, jeb->free_size)))
76 return ret;
77 /* Turned wasted size into dirty, since we apparently
78 think it's recoverable now. */
79 jeb->dirty_size += jeb->wasted_size;
80 c->dirty_size += jeb->wasted_size;
81 c->wasted_size -= jeb->wasted_size;
82 jeb->wasted_size = 0;
83 if (VERYDIRTY(c, jeb->dirty_size)) {
84 list_add(&jeb->list, &c->very_dirty_list);
85 } else {
86 list_add(&jeb->list, &c->dirty_list);
87 }
88 return 0;
89 }
90
91 int jffs2_scan_medium(struct jffs2_sb_info *c)
92 {
93 int i, ret;
94 uint32_t empty_blocks = 0, bad_blocks = 0;
95 unsigned char *flashbuf = NULL;
96 uint32_t buf_size = 0;
97 struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
98 #ifndef __ECOS
99 size_t pointlen, try_size;
100
101 ret = mtd_point(c->mtd, 0, c->mtd->size, &pointlen,
102 (void **)&flashbuf, NULL);
103 if (!ret && pointlen < c->mtd->size) {
104 /* Don't muck about if it won't let us point to the whole flash */
105 jffs2_dbg(1, "MTD point returned len too short: 0x%zx\n",
106 pointlen);
107 mtd_unpoint(c->mtd, 0, pointlen);
108 flashbuf = NULL;
109 }
110 if (ret && ret != -EOPNOTSUPP)
111 jffs2_dbg(1, "MTD point failed %d\n", ret);
112 #endif
113 if (!flashbuf) {
114 /* For NAND it's quicker to read a whole eraseblock at a time,
115 apparently */
116 if (jffs2_cleanmarker_oob(c))
117 try_size = c->sector_size;
118 else
119 try_size = PAGE_SIZE;
120
121 jffs2_dbg(1, "Trying to allocate readbuf of %zu "
122 "bytes\n", try_size);
123
124 flashbuf = mtd_kmalloc_up_to(c->mtd, &try_size);
125 if (!flashbuf)
126 return -ENOMEM;
127
128 jffs2_dbg(1, "Allocated readbuf of %zu bytes\n",
129 try_size);
130
131 buf_size = (uint32_t)try_size;
132 }
133
134 if (jffs2_sum_active()) {
135 s = kzalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
136 if (!s) {
137 JFFS2_WARNING("Can't allocate memory for summary\n");
138 ret = -ENOMEM;
139 goto out;
140 }
141 }
142
143 for (i=0; i<c->nr_blocks; i++) {
144 struct jffs2_eraseblock *jeb = &c->blocks[i];
145
146 cond_resched();
147
148 /* reset summary info for next eraseblock scan */
149 jffs2_sum_reset_collected(s);
150
151 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
152 buf_size, s);
153
154 if (ret < 0)
155 goto out;
156
157 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
158
159 /* Now decide which list to put it on */
160 switch(ret) {
161 case BLK_STATE_ALLFF:
162 /*
163 * Empty block. Since we can't be sure it
164 * was entirely erased, we just queue it for erase
165 * again. It will be marked as such when the erase
166 * is complete. Meanwhile we still count it as empty
167 * for later checks.
168 */
169 empty_blocks++;
170 list_add(&jeb->list, &c->erase_pending_list);
171 c->nr_erasing_blocks++;
172 break;
173
174 case BLK_STATE_CLEANMARKER:
175 /* Only a CLEANMARKER node is valid */
176 if (!jeb->dirty_size) {
177 /* It's actually free */
178 list_add(&jeb->list, &c->free_list);
179 c->nr_free_blocks++;
180 } else {
181 /* Dirt */
182 jffs2_dbg(1, "Adding all-dirty block at 0x%08x to erase_pending_list\n",
183 jeb->offset);
184 list_add(&jeb->list, &c->erase_pending_list);
185 c->nr_erasing_blocks++;
186 }
187 break;
188
189 case BLK_STATE_CLEAN:
190 /* Full (or almost full) of clean data. Clean list */
191 list_add(&jeb->list, &c->clean_list);
192 break;
193
194 case BLK_STATE_PARTDIRTY:
195 /* Some data, but not full. Dirty list. */
196 /* We want to remember the block with most free space
197 and stick it in the 'nextblock' position to start writing to it. */
198 if (jeb->free_size > min_free(c) &&
199 (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
200 /* Better candidate for the next writes to go to */
201 if (c->nextblock) {
202 ret = file_dirty(c, c->nextblock);
203 if (ret)
204 goto out;
205 /* deleting summary information of the old nextblock */
206 jffs2_sum_reset_collected(c->summary);
207 }
208 /* update collected summary information for the current nextblock */
209 jffs2_sum_move_collected(c, s);
210 jffs2_dbg(1, "%s(): new nextblock = 0x%08x\n",
211 __func__, jeb->offset);
212 c->nextblock = jeb;
213 } else {
214 ret = file_dirty(c, jeb);
215 if (ret)
216 goto out;
217 }
218 break;
219
220 case BLK_STATE_ALLDIRTY:
221 /* Nothing valid - not even a clean marker. Needs erasing. */
222 /* For now we just put it on the erasing list. We'll start the erases later */
223 jffs2_dbg(1, "Erase block at 0x%08x is not formatted. It will be erased\n",
224 jeb->offset);
225 list_add(&jeb->list, &c->erase_pending_list);
226 c->nr_erasing_blocks++;
227 break;
228
229 case BLK_STATE_BADBLOCK:
230 jffs2_dbg(1, "Block at 0x%08x is bad\n", jeb->offset);
231 list_add(&jeb->list, &c->bad_list);
232 c->bad_size += c->sector_size;
233 c->free_size -= c->sector_size;
234 bad_blocks++;
235 break;
236 default:
237 pr_warn("%s(): unknown block state\n", __func__);
238 BUG();
239 }
240 }
241
242 /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
243 if (c->nextblock && (c->nextblock->dirty_size)) {
244 c->nextblock->wasted_size += c->nextblock->dirty_size;
245 c->wasted_size += c->nextblock->dirty_size;
246 c->dirty_size -= c->nextblock->dirty_size;
247 c->nextblock->dirty_size = 0;
248 }
249 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
250 if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
251 /* If we're going to start writing into a block which already
252 contains data, and the end of the data isn't page-aligned,
253 skip a little and align it. */
254
255 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;
256
257 jffs2_dbg(1, "%s(): Skipping %d bytes in nextblock to ensure page alignment\n",
258 __func__, skip);
259 jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);
260 jffs2_scan_dirty_space(c, c->nextblock, skip);
261 }
262 #endif
263 if (c->nr_erasing_blocks) {
264 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
265 pr_notice("Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
266 pr_notice("empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",
267 empty_blocks, bad_blocks, c->nr_blocks);
268 ret = -EIO;
269 goto out;
270 }
271 spin_lock(&c->erase_completion_lock);
272 jffs2_garbage_collect_trigger(c);
273 spin_unlock(&c->erase_completion_lock);
274 }
275 ret = 0;
276 out:
277 if (buf_size)
278 kfree(flashbuf);
279 #ifndef __ECOS
280 else
281 mtd_unpoint(c->mtd, 0, c->mtd->size);
282 #endif
283 kfree(s);
284 return ret;
285 }
286
287 static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf,
288 uint32_t ofs, uint32_t len)
289 {
290 int ret;
291 size_t retlen;
292
293 ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
294 if (ret) {
295 jffs2_dbg(1, "mtd->read(0x%x bytes from 0x%x) returned %d\n",
296 len, ofs, ret);
297 return ret;
298 }
299 if (retlen < len) {
300 jffs2_dbg(1, "Read at 0x%x gave only 0x%zx bytes\n",
301 ofs, retlen);
302 return -EIO;
303 }
304 return 0;
305 }
306
307 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
308 {
309 if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
310 && (!jeb->first_node || !ref_next(jeb->first_node)) )
311 return BLK_STATE_CLEANMARKER;
312
313 /* move blocks with max 4 byte dirty space to cleanlist */
314 else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
315 c->dirty_size -= jeb->dirty_size;
316 c->wasted_size += jeb->dirty_size;
317 jeb->wasted_size += jeb->dirty_size;
318 jeb->dirty_size = 0;
319 return BLK_STATE_CLEAN;
320 } else if (jeb->used_size || jeb->unchecked_size)
321 return BLK_STATE_PARTDIRTY;
322 else
323 return BLK_STATE_ALLDIRTY;
324 }
325
326 #ifdef CONFIG_JFFS2_FS_XATTR
327 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
328 struct jffs2_raw_xattr *rx, uint32_t ofs,
329 struct jffs2_summary *s)
330 {
331 struct jffs2_xattr_datum *xd;
332 uint32_t xid, version, totlen, crc;
333 int err;
334
335 crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
336 if (crc != je32_to_cpu(rx->node_crc)) {
337 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
338 ofs, je32_to_cpu(rx->node_crc), crc);
339 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
340 return err;
341 return 0;
342 }
343
344 xid = je32_to_cpu(rx->xid);
345 version = je32_to_cpu(rx->version);
346
347 totlen = PAD(sizeof(struct jffs2_raw_xattr)
348 + rx->name_len + 1 + je16_to_cpu(rx->value_len));
349 if (totlen != je32_to_cpu(rx->totlen)) {
350 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
351 ofs, je32_to_cpu(rx->totlen), totlen);
352 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
353 return err;
354 return 0;
355 }
356
357 xd = jffs2_setup_xattr_datum(c, xid, version);
358 if (IS_ERR(xd))
359 return PTR_ERR(xd);
360
361 if (xd->version > version) {
362 struct jffs2_raw_node_ref *raw
363 = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
364 raw->next_in_ino = xd->node->next_in_ino;
365 xd->node->next_in_ino = raw;
366 } else {
367 xd->version = version;
368 xd->xprefix = rx->xprefix;
369 xd->name_len = rx->name_len;
370 xd->value_len = je16_to_cpu(rx->value_len);
371 xd->data_crc = je32_to_cpu(rx->data_crc);
372
373 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
374 }
375
376 if (jffs2_sum_active())
377 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
378 dbg_xattr("scanning xdatum at %#08x (xid=%u, version=%u)\n",
379 ofs, xd->xid, xd->version);
380 return 0;
381 }
382
383 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
384 struct jffs2_raw_xref *rr, uint32_t ofs,
385 struct jffs2_summary *s)
386 {
387 struct jffs2_xattr_ref *ref;
388 uint32_t crc;
389 int err;
390
391 crc = crc32(0, rr, sizeof(*rr) - 4);
392 if (crc != je32_to_cpu(rr->node_crc)) {
393 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
394 ofs, je32_to_cpu(rr->node_crc), crc);
395 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
396 return err;
397 return 0;
398 }
399
400 if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
401 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n",
402 ofs, je32_to_cpu(rr->totlen),
403 PAD(sizeof(struct jffs2_raw_xref)));
404 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
405 return err;
406 return 0;
407 }
408
409 ref = jffs2_alloc_xattr_ref();
410 if (!ref)
411 return -ENOMEM;
412
413 /* BEFORE jffs2_build_xattr_subsystem() called,
414 * and AFTER xattr_ref is marked as a dead xref,
415 * ref->xid is used to store 32bit xid, xd is not used
416 * ref->ino is used to store 32bit inode-number, ic is not used
417 * Thoes variables are declared as union, thus using those
418 * are exclusive. In a similar way, ref->next is temporarily
419 * used to chain all xattr_ref object. It's re-chained to
420 * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
421 */
422 ref->ino = je32_to_cpu(rr->ino);
423 ref->xid = je32_to_cpu(rr->xid);
424 ref->xseqno = je32_to_cpu(rr->xseqno);
425 if (ref->xseqno > c->highest_xseqno)
426 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
427 ref->next = c->xref_temp;
428 c->xref_temp = ref;
429
430 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);
431
432 if (jffs2_sum_active())
433 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
434 dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
435 ofs, ref->xid, ref->ino);
436 return 0;
437 }
438 #endif
439
440 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
441 the flash, XIP-style */
442 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
443 unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
444 struct jffs2_unknown_node *node;
445 struct jffs2_unknown_node crcnode;
446 uint32_t ofs, prevofs, max_ofs;
447 uint32_t hdr_crc, buf_ofs, buf_len;
448 int err;
449 int noise = 0;
450
451
452 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
453 int cleanmarkerfound = 0;
454 #endif
455
456 ofs = jeb->offset;
457 prevofs = jeb->offset - 1;
458
459 jffs2_dbg(1, "%s(): Scanning block at 0x%x\n", __func__, ofs);
460
461 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
462 if (jffs2_cleanmarker_oob(c)) {
463 int ret;
464
465 if (mtd_block_isbad(c->mtd, jeb->offset))
466 return BLK_STATE_BADBLOCK;
467
468 ret = jffs2_check_nand_cleanmarker(c, jeb);
469 jffs2_dbg(2, "jffs_check_nand_cleanmarker returned %d\n", ret);
470
471 /* Even if it's not found, we still scan to see
472 if the block is empty. We use this information
473 to decide whether to erase it or not. */
474 switch (ret) {
475 case 0: cleanmarkerfound = 1; break;
476 case 1: break;
477 default: return ret;
478 }
479 }
480 #endif
481
482 if (jffs2_sum_active()) {
483 struct jffs2_sum_marker *sm;
484 void *sumptr = NULL;
485 uint32_t sumlen;
486
487 if (!buf_size) {
488 /* XIP case. Just look, point at the summary if it's there */
489 sm = (void *)buf + c->sector_size - sizeof(*sm);
490 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
491 sumptr = buf + je32_to_cpu(sm->offset);
492 sumlen = c->sector_size - je32_to_cpu(sm->offset);
493 }
494 } else {
495 /* If NAND flash, read a whole page of it. Else just the end */
496 if (c->wbuf_pagesize)
497 buf_len = c->wbuf_pagesize;
498 else
499 buf_len = sizeof(*sm);
500
501 /* Read as much as we want into the _end_ of the preallocated buffer */
502 err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len,
503 jeb->offset + c->sector_size - buf_len,
504 buf_len);
505 if (err)
506 return err;
507
508 sm = (void *)buf + buf_size - sizeof(*sm);
509 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
510 sumlen = c->sector_size - je32_to_cpu(sm->offset);
511 sumptr = buf + buf_size - sumlen;
512
513 /* Now, make sure the summary itself is available */
514 if (sumlen > buf_size) {
515 /* Need to kmalloc for this. */
516 sumptr = kmalloc(sumlen, GFP_KERNEL);
517 if (!sumptr)
518 return -ENOMEM;
519 memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
520 }
521 if (buf_len < sumlen) {
522 /* Need to read more so that the entire summary node is present */
523 err = jffs2_fill_scan_buf(c, sumptr,
524 jeb->offset + c->sector_size - sumlen,
525 sumlen - buf_len);
526 if (err)
527 return err;
528 }
529 }
530
531 }
532
533 if (sumptr) {
534 err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);
535
536 if (buf_size && sumlen > buf_size)
537 kfree(sumptr);
538 /* If it returns with a real error, bail.
539 If it returns positive, that's a block classification
540 (i.e. BLK_STATE_xxx) so return that too.
541 If it returns zero, fall through to full scan. */
542 if (err)
543 return err;
544 }
545 }
546
547 buf_ofs = jeb->offset;
548
549 if (!buf_size) {
550 /* This is the XIP case -- we're reading _directly_ from the flash chip */
551 buf_len = c->sector_size;
552 } else {
553 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
554 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
555 if (err)
556 return err;
557 }
558
559 /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
560 ofs = 0;
561 max_ofs = EMPTY_SCAN_SIZE(c->sector_size);
562 /* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */
563 while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
564 ofs += 4;
565
566 if (ofs == max_ofs) {
567 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
568 if (jffs2_cleanmarker_oob(c)) {
569 /* scan oob, take care of cleanmarker */
570 int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
571 jffs2_dbg(2, "jffs2_check_oob_empty returned %d\n",
572 ret);
573 switch (ret) {
574 case 0: return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
575 case 1: return BLK_STATE_ALLDIRTY;
576 default: return ret;
577 }
578 }
579 #endif
580 jffs2_dbg(1, "Block at 0x%08x is empty (erased)\n",
581 jeb->offset);
582 if (c->cleanmarker_size == 0)
583 return BLK_STATE_CLEANMARKER; /* don't bother with re-erase */
584 else
585 return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
586 }
587 if (ofs) {
588 jffs2_dbg(1, "Free space at %08x ends at %08x\n", jeb->offset,
589 jeb->offset + ofs);
590 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
591 return err;
592 if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
593 return err;
594 }
595
596 /* Now ofs is a complete physical flash offset as it always was... */
597 ofs += jeb->offset;
598
599 noise = 10;
600
601 dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset);
602
603 scan_more:
604 while(ofs < jeb->offset + c->sector_size) {
605
606 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
607
608 /* Make sure there are node refs available for use */
609 err = jffs2_prealloc_raw_node_refs(c, jeb, 2);
610 if (err)
611 return err;
612
613 cond_resched();
614
615 if (ofs & 3) {
616 pr_warn("Eep. ofs 0x%08x not word-aligned!\n", ofs);
617 ofs = PAD(ofs);
618 continue;
619 }
620 if (ofs == prevofs) {
621 pr_warn("ofs 0x%08x has already been seen. Skipping\n",
622 ofs);
623 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
624 return err;
625 ofs += 4;
626 continue;
627 }
628 prevofs = ofs;
629
630 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
631 jffs2_dbg(1, "Fewer than %zd bytes left to end of block. (%x+%x<%x+%zx) Not reading\n",
632 sizeof(struct jffs2_unknown_node),
633 jeb->offset, c->sector_size, ofs,
634 sizeof(*node));
635 if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
636 return err;
637 break;
638 }
639
640 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
641 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
642 jffs2_dbg(1, "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
643 sizeof(struct jffs2_unknown_node),
644 buf_len, ofs);
645 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
646 if (err)
647 return err;
648 buf_ofs = ofs;
649 }
650
651 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
652
653 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
654 uint32_t inbuf_ofs;
655 uint32_t empty_start, scan_end;
656
657 empty_start = ofs;
658 ofs += 4;
659 scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);
660
661 jffs2_dbg(1, "Found empty flash at 0x%08x\n", ofs);
662 more_empty:
663 inbuf_ofs = ofs - buf_ofs;
664 while (inbuf_ofs < scan_end) {
665 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {
666 pr_warn("Empty flash at 0x%08x ends at 0x%08x\n",
667 empty_start, ofs);
668 if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
669 return err;
670 goto scan_more;
671 }
672
673 inbuf_ofs+=4;
674 ofs += 4;
675 }
676 /* Ran off end. */
677 jffs2_dbg(1, "Empty flash to end of buffer at 0x%08x\n",
678 ofs);
679
680 /* If we're only checking the beginning of a block with a cleanmarker,
681 bail now */
682 if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&
683 c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {
684 jffs2_dbg(1, "%d bytes at start of block seems clean... assuming all clean\n",
685 EMPTY_SCAN_SIZE(c->sector_size));
686 return BLK_STATE_CLEANMARKER;
687 }
688 if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
689 scan_end = buf_len;
690 goto more_empty;
691 }
692
693 /* See how much more there is to read in this eraseblock... */
694 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
695 if (!buf_len) {
696 /* No more to read. Break out of main loop without marking
697 this range of empty space as dirty (because it's not) */
698 jffs2_dbg(1, "Empty flash at %08x runs to end of block. Treating as free_space\n",
699 empty_start);
700 break;
701 }
702 /* point never reaches here */
703 scan_end = buf_len;
704 jffs2_dbg(1, "Reading another 0x%x at 0x%08x\n",
705 buf_len, ofs);
706 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
707 if (err)
708 return err;
709 buf_ofs = ofs;
710 goto more_empty;
711 }
712
713 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
714 pr_warn("Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n",
715 ofs);
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_DIRTY_BITMASK) {
722 jffs2_dbg(1, "Dirty bitmask at 0x%08x\n", ofs);
723 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
724 return err;
725 ofs += 4;
726 continue;
727 }
728 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
729 pr_warn("Old JFFS2 bitmask found at 0x%08x\n", ofs);
730 pr_warn("You cannot use older JFFS2 filesystems with newer kernels\n");
731 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
732 return err;
733 ofs += 4;
734 continue;
735 }
736 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
737 /* OK. We're out of possibilities. Whinge and move on */
738 noisy_printk(&noise, "%s(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n",
739 __func__,
740 JFFS2_MAGIC_BITMASK, ofs,
741 je16_to_cpu(node->magic));
742 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
743 return err;
744 ofs += 4;
745 continue;
746 }
747 /* We seem to have a node of sorts. Check the CRC */
748 crcnode.magic = node->magic;
749 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
750 crcnode.totlen = node->totlen;
751 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
752
753 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
754 noisy_printk(&noise, "%s(): Node at 0x%08x {0x%04x, 0x%04x, 0x%08x) has invalid CRC 0x%08x (calculated 0x%08x)\n",
755 __func__,
756 ofs, je16_to_cpu(node->magic),
757 je16_to_cpu(node->nodetype),
758 je32_to_cpu(node->totlen),
759 je32_to_cpu(node->hdr_crc),
760 hdr_crc);
761 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
762 return err;
763 ofs += 4;
764 continue;
765 }
766
767 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) {
768 /* Eep. Node goes over the end of the erase block. */
769 pr_warn("Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
770 ofs, je32_to_cpu(node->totlen));
771 pr_warn("Perhaps the file system was created with the wrong erase size?\n");
772 if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
773 return err;
774 ofs += 4;
775 continue;
776 }
777
778 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
779 /* Wheee. This is an obsoleted node */
780 jffs2_dbg(2, "Node at 0x%08x is obsolete. Skipping\n",
781 ofs);
782 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
783 return err;
784 ofs += PAD(je32_to_cpu(node->totlen));
785 continue;
786 }
787
788 switch(je16_to_cpu(node->nodetype)) {
789 case JFFS2_NODETYPE_INODE:
790 if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
791 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
792 jffs2_dbg(1, "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
793 sizeof(struct jffs2_raw_inode),
794 buf_len, ofs);
795 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
796 if (err)
797 return err;
798 buf_ofs = ofs;
799 node = (void *)buf;
800 }
801 err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);
802 if (err) return err;
803 ofs += PAD(je32_to_cpu(node->totlen));
804 break;
805
806 case JFFS2_NODETYPE_DIRENT:
807 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
808 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
809 jffs2_dbg(1, "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
810 je32_to_cpu(node->totlen), buf_len,
811 ofs);
812 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
813 if (err)
814 return err;
815 buf_ofs = ofs;
816 node = (void *)buf;
817 }
818 err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);
819 if (err) return err;
820 ofs += PAD(je32_to_cpu(node->totlen));
821 break;
822
823 #ifdef CONFIG_JFFS2_FS_XATTR
824 case JFFS2_NODETYPE_XATTR:
825 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
826 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
827 jffs2_dbg(1, "Fewer than %d bytes (xattr node) left to end of buf. Reading 0x%x at 0x%08x\n",
828 je32_to_cpu(node->totlen), buf_len,
829 ofs);
830 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
831 if (err)
832 return err;
833 buf_ofs = ofs;
834 node = (void *)buf;
835 }
836 err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
837 if (err)
838 return err;
839 ofs += PAD(je32_to_cpu(node->totlen));
840 break;
841 case JFFS2_NODETYPE_XREF:
842 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
843 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
844 jffs2_dbg(1, "Fewer than %d bytes (xref node) left to end of buf. Reading 0x%x at 0x%08x\n",
845 je32_to_cpu(node->totlen), buf_len,
846 ofs);
847 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
848 if (err)
849 return err;
850 buf_ofs = ofs;
851 node = (void *)buf;
852 }
853 err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
854 if (err)
855 return err;
856 ofs += PAD(je32_to_cpu(node->totlen));
857 break;
858 #endif /* CONFIG_JFFS2_FS_XATTR */
859
860 case JFFS2_NODETYPE_CLEANMARKER:
861 jffs2_dbg(1, "CLEANMARKER node found at 0x%08x\n", ofs);
862 if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
863 pr_notice("CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n",
864 ofs, je32_to_cpu(node->totlen),
865 c->cleanmarker_size);
866 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
867 return err;
868 ofs += PAD(sizeof(struct jffs2_unknown_node));
869 } else if (jeb->first_node) {
870 pr_notice("CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n",
871 ofs, jeb->offset);
872 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
873 return err;
874 ofs += PAD(sizeof(struct jffs2_unknown_node));
875 } else {
876 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);
877
878 ofs += PAD(c->cleanmarker_size);
879 }
880 break;
881
882 case JFFS2_NODETYPE_PADDING:
883 if (jffs2_sum_active())
884 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));
885 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
886 return err;
887 ofs += PAD(je32_to_cpu(node->totlen));
888 break;
889
890 default:
891 switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
892 case JFFS2_FEATURE_ROCOMPAT:
893 pr_notice("Read-only compatible feature node (0x%04x) found at offset 0x%08x\n",
894 je16_to_cpu(node->nodetype), ofs);
895 c->flags |= JFFS2_SB_FLAG_RO;
896 if (!(jffs2_is_readonly(c)))
897 return -EROFS;
898 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
899 return err;
900 ofs += PAD(je32_to_cpu(node->totlen));
901 break;
902
903 case JFFS2_FEATURE_INCOMPAT:
904 pr_notice("Incompatible feature node (0x%04x) found at offset 0x%08x\n",
905 je16_to_cpu(node->nodetype), ofs);
906 return -EINVAL;
907
908 case JFFS2_FEATURE_RWCOMPAT_DELETE:
909 jffs2_dbg(1, "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n",
910 je16_to_cpu(node->nodetype), ofs);
911 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
912 return err;
913 ofs += PAD(je32_to_cpu(node->totlen));
914 break;
915
916 case JFFS2_FEATURE_RWCOMPAT_COPY: {
917 jffs2_dbg(1, "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n",
918 je16_to_cpu(node->nodetype), ofs);
919
920 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);
921
922 /* We can't summarise nodes we don't grok */
923 jffs2_sum_disable_collecting(s);
924 ofs += PAD(je32_to_cpu(node->totlen));
925 break;
926 }
927 }
928 }
929 }
930
931 if (jffs2_sum_active()) {
932 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {
933 dbg_summary("There is not enough space for "
934 "summary information, disabling for this jeb!\n");
935 jffs2_sum_disable_collecting(s);
936 }
937 }
938
939 jffs2_dbg(1, "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n",
940 jeb->offset, jeb->free_size, jeb->dirty_size,
941 jeb->unchecked_size, jeb->used_size, jeb->wasted_size);
942
943 /* mark_node_obsolete can add to wasted !! */
944 if (jeb->wasted_size) {
945 jeb->dirty_size += jeb->wasted_size;
946 c->dirty_size += jeb->wasted_size;
947 c->wasted_size -= jeb->wasted_size;
948 jeb->wasted_size = 0;
949 }
950
951 return jffs2_scan_classify_jeb(c, jeb);
952 }
953
954 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
955 {
956 struct jffs2_inode_cache *ic;
957
958 ic = jffs2_get_ino_cache(c, ino);
959 if (ic)
960 return ic;
961
962 if (ino > c->highest_ino)
963 c->highest_ino = ino;
964
965 ic = jffs2_alloc_inode_cache();
966 if (!ic) {
967 pr_notice("%s(): allocation of inode cache failed\n", __func__);
968 return NULL;
969 }
970 memset(ic, 0, sizeof(*ic));
971
972 ic->ino = ino;
973 ic->nodes = (void *)ic;
974 jffs2_add_ino_cache(c, ic);
975 if (ino == 1)
976 ic->pino_nlink = 1;
977 return ic;
978 }
979
980 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
981 struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)
982 {
983 struct jffs2_inode_cache *ic;
984 uint32_t crc, ino = je32_to_cpu(ri->ino);
985
986 jffs2_dbg(1, "%s(): Node at 0x%08x\n", __func__, ofs);
987
988 /* We do very little here now. Just check the ino# to which we should attribute
989 this node; we can do all the CRC checking etc. later. There's a tradeoff here --
990 we used to scan the flash once only, reading everything we want from it into
991 memory, then building all our in-core data structures and freeing the extra
992 information. Now we allow the first part of the mount to complete a lot quicker,
993 but we have to go _back_ to the flash in order to finish the CRC checking, etc.
994 Which means that the _full_ amount of time to get to proper write mode with GC
995 operational may actually be _longer_ than before. Sucks to be me. */
996
997 /* Check the node CRC in any case. */
998 crc = crc32(0, ri, sizeof(*ri)-8);
999 if (crc != je32_to_cpu(ri->node_crc)) {
1000 pr_notice("%s(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1001 __func__, ofs, je32_to_cpu(ri->node_crc), crc);
1002 /*
1003 * We believe totlen because the CRC on the node
1004 * _header_ was OK, just the node itself failed.
1005 */
1006 return jffs2_scan_dirty_space(c, jeb,
1007 PAD(je32_to_cpu(ri->totlen)));
1008 }
1009
1010 ic = jffs2_get_ino_cache(c, ino);
1011 if (!ic) {
1012 ic = jffs2_scan_make_ino_cache(c, ino);
1013 if (!ic)
1014 return -ENOMEM;
1015 }
1016
1017 /* Wheee. It worked */
1018 jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);
1019
1020 jffs2_dbg(1, "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
1021 je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
1022 je32_to_cpu(ri->offset),
1023 je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize));
1024
1025 pseudo_random += je32_to_cpu(ri->version);
1026
1027 if (jffs2_sum_active()) {
1028 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
1029 }
1030
1031 return 0;
1032 }
1033
1034 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1035 struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)
1036 {
1037 struct jffs2_full_dirent *fd;
1038 struct jffs2_inode_cache *ic;
1039 uint32_t checkedlen;
1040 uint32_t crc;
1041 int err;
1042
1043 jffs2_dbg(1, "%s(): Node at 0x%08x\n", __func__, ofs);
1044
1045 /* We don't get here unless the node is still valid, so we don't have to
1046 mask in the ACCURATE bit any more. */
1047 crc = crc32(0, rd, sizeof(*rd)-8);
1048
1049 if (crc != je32_to_cpu(rd->node_crc)) {
1050 pr_notice("%s(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1051 __func__, ofs, je32_to_cpu(rd->node_crc), crc);
1052 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
1053 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1054 return err;
1055 return 0;
1056 }
1057
1058 pseudo_random += je32_to_cpu(rd->version);
1059
1060 /* Should never happen. Did. (OLPC trac #4184)*/
1061 checkedlen = strnlen(rd->name, rd->nsize);
1062 if (checkedlen < rd->nsize) {
1063 pr_err("Dirent at %08x has zeroes in name. Truncating to %d chars\n",
1064 ofs, checkedlen);
1065 }
1066 fd = jffs2_alloc_full_dirent(checkedlen+1);
1067 if (!fd) {
1068 return -ENOMEM;
1069 }
1070 memcpy(&fd->name, rd->name, checkedlen);
1071 fd->name[checkedlen] = 0;
1072
1073 crc = crc32(0, fd->name, rd->nsize);
1074 if (crc != je32_to_cpu(rd->name_crc)) {
1075 pr_notice("%s(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
1076 __func__, ofs, je32_to_cpu(rd->name_crc), crc);
1077 jffs2_dbg(1, "Name for which CRC failed is (now) '%s', ino #%d\n",
1078 fd->name, je32_to_cpu(rd->ino));
1079 jffs2_free_full_dirent(fd);
1080 /* FIXME: Why do we believe totlen? */
1081 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
1082 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
1083 return err;
1084 return 0;
1085 }
1086 ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
1087 if (!ic) {
1088 jffs2_free_full_dirent(fd);
1089 return -ENOMEM;
1090 }
1091
1092 fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
1093 PAD(je32_to_cpu(rd->totlen)), ic);
1094
1095 fd->next = NULL;
1096 fd->version = je32_to_cpu(rd->version);
1097 fd->ino = je32_to_cpu(rd->ino);
1098 fd->nhash = full_name_hash(fd->name, checkedlen);
1099 fd->type = rd->type;
1100 jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
1101
1102 if (jffs2_sum_active()) {
1103 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
1104 }
1105
1106 return 0;
1107 }
1108
1109 static int count_list(struct list_head *l)
1110 {
1111 uint32_t count = 0;
1112 struct list_head *tmp;
1113
1114 list_for_each(tmp, l) {
1115 count++;
1116 }
1117 return count;
1118 }
1119
1120 /* Note: This breaks if list_empty(head). I don't care. You
1121 might, if you copy this code and use it elsewhere :) */
1122 static void rotate_list(struct list_head *head, uint32_t count)
1123 {
1124 struct list_head *n = head->next;
1125
1126 list_del(head);
1127 while(count--) {
1128 n = n->next;
1129 }
1130 list_add(head, n);
1131 }
1132
1133 void jffs2_rotate_lists(struct jffs2_sb_info *c)
1134 {
1135 uint32_t x;
1136 uint32_t rotateby;
1137
1138 x = count_list(&c->clean_list);
1139 if (x) {
1140 rotateby = pseudo_random % x;
1141 rotate_list((&c->clean_list), rotateby);
1142 }
1143
1144 x = count_list(&c->very_dirty_list);
1145 if (x) {
1146 rotateby = pseudo_random % x;
1147 rotate_list((&c->very_dirty_list), rotateby);
1148 }
1149
1150 x = count_list(&c->dirty_list);
1151 if (x) {
1152 rotateby = pseudo_random % x;
1153 rotate_list((&c->dirty_list), rotateby);
1154 }
1155
1156 x = count_list(&c->erasable_list);
1157 if (x) {
1158 rotateby = pseudo_random % x;
1159 rotate_list((&c->erasable_list), rotateby);
1160 }
1161
1162 if (c->nr_erasing_blocks) {
1163 rotateby = pseudo_random % c->nr_erasing_blocks;
1164 rotate_list((&c->erase_pending_list), rotateby);
1165 }
1166
1167 if (c->nr_free_blocks) {
1168 rotateby = pseudo_random % c->nr_free_blocks;
1169 rotate_list((&c->free_list), rotateby);
1170 }
1171 }
Linus' kernel tree