[JFFS2] Debug code clean up - step 3
[linux-2.6.git] / fs / jffs2 / scan.c
1 /*
2  * JFFS2 -- Journalling Flash File System, Version 2.
3  *
4  * Copyright (C) 2001-2003 Red Hat, Inc.
5  *
6  * Created by David Woodhouse <dwmw2@infradead.org>
7  *
8  * For licensing information, see the file 'LICENCE' in this directory.
9  *
10  * $Id: scan.c,v 1.121 2005/07/20 15:32:28 dedekind Exp $
11  *
12  */
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15 #include <linux/slab.h>
16 #include <linux/mtd/mtd.h>
17 #include <linux/pagemap.h>
18 #include <linux/crc32.h>
19 #include <linux/compiler.h>
20 #include "nodelist.h"
21
22 #define DEFAULT_EMPTY_SCAN_SIZE 1024
23
24 #define DIRTY_SPACE(x) do { typeof(x) _x = (x); \
25                 c->free_size -= _x; c->dirty_size += _x; \
26                 jeb->free_size -= _x ; jeb->dirty_size += _x; \
27                 }while(0)
28 #define USED_SPACE(x) do { typeof(x) _x = (x); \
29                 c->free_size -= _x; c->used_size += _x; \
30                 jeb->free_size -= _x ; jeb->used_size += _x; \
31                 }while(0)
32 #define UNCHECKED_SPACE(x) do { typeof(x) _x = (x); \
33                 c->free_size -= _x; c->unchecked_size += _x; \
34                 jeb->free_size -= _x ; jeb->unchecked_size += _x; \
35                 }while(0)
36
37 #define noisy_printk(noise, args...) do { \
38         if (*(noise)) { \
39                 printk(KERN_NOTICE args); \
40                  (*(noise))--; \
41                  if (!(*(noise))) { \
42                          printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \
43                  } \
44         } \
45 } while(0)
46
47 static uint32_t pseudo_random;
48
49 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
50                                   unsigned char *buf, uint32_t buf_size);
51
52 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting. 
53  * Returning an error will abort the mount - bad checksums etc. should just mark the space
54  * as dirty.
55  */
56 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 
57                                  struct jffs2_raw_inode *ri, uint32_t ofs);
58 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
59                                  struct jffs2_raw_dirent *rd, uint32_t ofs);
60
61 #define BLK_STATE_ALLFF         0
62 #define BLK_STATE_CLEAN         1
63 #define BLK_STATE_PARTDIRTY     2
64 #define BLK_STATE_CLEANMARKER   3
65 #define BLK_STATE_ALLDIRTY      4
66 #define BLK_STATE_BADBLOCK      5
67
68 static inline int min_free(struct jffs2_sb_info *c)
69 {
70         uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
71 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
72         if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
73                 return c->wbuf_pagesize;
74 #endif
75         return min;
76
77 }
78
79 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
80         if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
81                 return sector_size;
82         else
83                 return DEFAULT_EMPTY_SCAN_SIZE;
84 }
85
86 int jffs2_scan_medium(struct jffs2_sb_info *c)
87 {
88         int i, ret;
89         uint32_t empty_blocks = 0, bad_blocks = 0;
90         unsigned char *flashbuf = NULL;
91         uint32_t buf_size = 0;
92 #ifndef __ECOS
93         size_t pointlen;
94
95         if (c->mtd->point) {
96                 ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
97                 if (!ret && pointlen < c->mtd->size) {
98                         /* Don't muck about if it won't let us point to the whole flash */
99                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
100                         c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
101                         flashbuf = NULL;
102                 }
103                 if (ret)
104                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
105         }
106 #endif
107         if (!flashbuf) {
108                 /* For NAND it's quicker to read a whole eraseblock at a time,
109                    apparently */
110                 if (jffs2_cleanmarker_oob(c))
111                         buf_size = c->sector_size;
112                 else
113                         buf_size = PAGE_SIZE;
114
115                 /* Respect kmalloc limitations */
116                 if (buf_size > 128*1024)
117                         buf_size = 128*1024;
118
119                 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
120                 flashbuf = kmalloc(buf_size, GFP_KERNEL);
121                 if (!flashbuf)
122                         return -ENOMEM;
123         }
124
125         for (i=0; i<c->nr_blocks; i++) {
126                 struct jffs2_eraseblock *jeb = &c->blocks[i];
127
128                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset), buf_size);
129
130                 if (ret < 0)
131                         goto out;
132
133                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
134
135                 /* Now decide which list to put it on */
136                 switch(ret) {
137                 case BLK_STATE_ALLFF:
138                         /* 
139                          * Empty block.   Since we can't be sure it 
140                          * was entirely erased, we just queue it for erase
141                          * again.  It will be marked as such when the erase
142                          * is complete.  Meanwhile we still count it as empty
143                          * for later checks.
144                          */
145                         empty_blocks++;
146                         list_add(&jeb->list, &c->erase_pending_list);
147                         c->nr_erasing_blocks++;
148                         break;
149
150                 case BLK_STATE_CLEANMARKER:
151                         /* Only a CLEANMARKER node is valid */
152                         if (!jeb->dirty_size) {
153                                 /* It's actually free */
154                                 list_add(&jeb->list, &c->free_list);
155                                 c->nr_free_blocks++;
156                         } else {
157                                 /* Dirt */
158                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
159                                 list_add(&jeb->list, &c->erase_pending_list);
160                                 c->nr_erasing_blocks++;
161                         }
162                         break;
163
164                 case BLK_STATE_CLEAN:
165                         /* Full (or almost full) of clean data. Clean list */
166                         list_add(&jeb->list, &c->clean_list);
167                         break;
168
169                 case BLK_STATE_PARTDIRTY:
170                         /* Some data, but not full. Dirty list. */
171                         /* We want to remember the block with most free space
172                            and stick it in the 'nextblock' position to start writing to it. */
173                         if (jeb->free_size > min_free(c) && 
174                             (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
175                                 /* Better candidate for the next writes to go to */
176                                 if (c->nextblock) {
177                                         c->nextblock->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
178                                         c->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
179                                         c->free_size -= c->nextblock->free_size;
180                                         c->wasted_size -= c->nextblock->wasted_size;
181                                         c->nextblock->free_size = c->nextblock->wasted_size = 0;
182                                         if (VERYDIRTY(c, c->nextblock->dirty_size)) {
183                                                 list_add(&c->nextblock->list, &c->very_dirty_list);
184                                         } else {
185                                                 list_add(&c->nextblock->list, &c->dirty_list);
186                                         }
187                                 }
188                                 c->nextblock = jeb;
189                         } else {
190                                 jeb->dirty_size += jeb->free_size + jeb->wasted_size;
191                                 c->dirty_size += jeb->free_size + jeb->wasted_size;
192                                 c->free_size -= jeb->free_size;
193                                 c->wasted_size -= jeb->wasted_size;
194                                 jeb->free_size = jeb->wasted_size = 0;
195                                 if (VERYDIRTY(c, jeb->dirty_size)) {
196                                         list_add(&jeb->list, &c->very_dirty_list);
197                                 } else {
198                                         list_add(&jeb->list, &c->dirty_list);
199                                 }
200                         }
201                         break;
202
203                 case BLK_STATE_ALLDIRTY:
204                         /* Nothing valid - not even a clean marker. Needs erasing. */
205                         /* For now we just put it on the erasing list. We'll start the erases later */
206                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
207                         list_add(&jeb->list, &c->erase_pending_list);
208                         c->nr_erasing_blocks++;
209                         break;
210                         
211                 case BLK_STATE_BADBLOCK:
212                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
213                         list_add(&jeb->list, &c->bad_list);
214                         c->bad_size += c->sector_size;
215                         c->free_size -= c->sector_size;
216                         bad_blocks++;
217                         break;
218                 default:
219                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
220                         BUG();  
221                 }
222         }
223         
224         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
225         if (c->nextblock && (c->nextblock->dirty_size)) {
226                 c->nextblock->wasted_size += c->nextblock->dirty_size;
227                 c->wasted_size += c->nextblock->dirty_size;
228                 c->dirty_size -= c->nextblock->dirty_size;
229                 c->nextblock->dirty_size = 0;
230         }
231 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
232         if (!jffs2_can_mark_obsolete(c) && c->nextblock && (c->nextblock->free_size & (c->wbuf_pagesize-1))) {
233                 /* If we're going to start writing into a block which already 
234                    contains data, and the end of the data isn't page-aligned,
235                    skip a little and align it. */
236
237                 uint32_t skip = c->nextblock->free_size & (c->wbuf_pagesize-1);
238
239                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
240                           skip));
241                 c->nextblock->wasted_size += skip;
242                 c->wasted_size += skip;
243
244                 c->nextblock->free_size -= skip;
245                 c->free_size -= skip;
246         }
247 #endif
248         if (c->nr_erasing_blocks) {
249                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) { 
250                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
251                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
252                         ret = -EIO;
253                         goto out;
254                 }
255                 jffs2_erase_pending_trigger(c);
256         }
257         ret = 0;
258  out:
259         if (buf_size)
260                 kfree(flashbuf);
261 #ifndef __ECOS
262         else 
263                 c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
264 #endif
265         return ret;
266 }
267
268 static int jffs2_fill_scan_buf (struct jffs2_sb_info *c, unsigned char *buf,
269                                 uint32_t ofs, uint32_t len)
270 {
271         int ret;
272         size_t retlen;
273
274         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
275         if (ret) {
276                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
277                 return ret;
278         }
279         if (retlen < len) {
280                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
281                 return -EIO;
282         }
283         D2(printk(KERN_DEBUG "Read 0x%x bytes from 0x%08x into buf\n", len, ofs));
284         D2(printk(KERN_DEBUG "000: %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
285                   buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7], buf[8], buf[9], buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]));
286         return 0;
287 }
288
289 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
290                                   unsigned char *buf, uint32_t buf_size) {
291         struct jffs2_unknown_node *node;
292         struct jffs2_unknown_node crcnode;
293         uint32_t ofs, prevofs;
294         uint32_t hdr_crc, buf_ofs, buf_len;
295         int err;
296         int noise = 0;
297 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
298         int cleanmarkerfound = 0;
299 #endif
300
301         ofs = jeb->offset;
302         prevofs = jeb->offset - 1;
303
304         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
305
306 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
307         if (jffs2_cleanmarker_oob(c)) {
308                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
309                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
310                 /* Even if it's not found, we still scan to see
311                    if the block is empty. We use this information
312                    to decide whether to erase it or not. */
313                 switch (ret) {
314                 case 0:         cleanmarkerfound = 1; break;
315                 case 1:         break;
316                 case 2:         return BLK_STATE_BADBLOCK;
317                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
318                 default:        return ret;
319                 }
320         }
321 #endif
322         buf_ofs = jeb->offset;
323
324         if (!buf_size) {
325                 buf_len = c->sector_size;
326         } else {
327                 buf_len = EMPTY_SCAN_SIZE(c->sector_size);
328                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
329                 if (err)
330                         return err;
331         }
332         
333         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
334         ofs = 0;
335
336         /* Scan only 4KiB of 0xFF before declaring it's empty */
337         while(ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
338                 ofs += 4;
339
340         if (ofs == EMPTY_SCAN_SIZE(c->sector_size)) {
341 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
342                 if (jffs2_cleanmarker_oob(c)) {
343                         /* scan oob, take care of cleanmarker */
344                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
345                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
346                         switch (ret) {
347                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
348                         case 1:         return BLK_STATE_ALLDIRTY;
349                         default:        return ret;
350                         }
351                 }
352 #endif
353                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
354                 if (c->cleanmarker_size == 0)
355                         return BLK_STATE_CLEANMARKER;   /* don't bother with re-erase */
356                 else
357                         return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
358         }
359         if (ofs) {
360                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
361                           jeb->offset + ofs));
362                 DIRTY_SPACE(ofs);
363         }
364
365         /* Now ofs is a complete physical flash offset as it always was... */
366         ofs += jeb->offset;
367
368         noise = 10;
369
370 scan_more:      
371         while(ofs < jeb->offset + c->sector_size) {
372
373                 jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
374
375                 cond_resched();
376
377                 if (ofs & 3) {
378                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
379                         ofs = PAD(ofs);
380                         continue;
381                 }
382                 if (ofs == prevofs) {
383                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
384                         DIRTY_SPACE(4);
385                         ofs += 4;
386                         continue;
387                 }
388                 prevofs = ofs;
389
390                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
391                         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),
392                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
393                         DIRTY_SPACE((jeb->offset + c->sector_size)-ofs);
394                         break;
395                 }
396
397                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
398                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
399                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
400                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
401                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
402                         if (err)
403                                 return err;
404                         buf_ofs = ofs;
405                 }
406
407                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
408
409                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
410                         uint32_t inbuf_ofs;
411                         uint32_t empty_start;
412
413                         empty_start = ofs;
414                         ofs += 4;
415
416                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
417                 more_empty:
418                         inbuf_ofs = ofs - buf_ofs;
419                         while (inbuf_ofs < buf_len) {
420                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
421                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
422                                                empty_start, ofs);
423                                         DIRTY_SPACE(ofs-empty_start);
424                                         goto scan_more;
425                                 }
426
427                                 inbuf_ofs+=4;
428                                 ofs += 4;
429                         }
430                         /* Ran off end. */
431                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
432
433                         /* If we're only checking the beginning of a block with a cleanmarker,
434                            bail now */
435                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) && 
436                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_phys) {
437                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
438                                 return BLK_STATE_CLEANMARKER;
439                         }
440
441                         /* See how much more there is to read in this eraseblock... */
442                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
443                         if (!buf_len) {
444                                 /* No more to read. Break out of main loop without marking 
445                                    this range of empty space as dirty (because it's not) */
446                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
447                                           empty_start));
448                                 break;
449                         }
450                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
451                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
452                         if (err)
453                                 return err;
454                         buf_ofs = ofs;
455                         goto more_empty;
456                 }
457
458                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
459                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
460                         DIRTY_SPACE(4);
461                         ofs += 4;
462                         continue;
463                 }
464                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
465                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
466                         DIRTY_SPACE(4);
467                         ofs += 4;
468                         continue;
469                 }
470                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
471                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
472                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
473                         DIRTY_SPACE(4);
474                         ofs += 4;
475                         continue;
476                 }
477                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
478                         /* OK. We're out of possibilities. Whinge and move on */
479                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n", 
480                                      JFFS2_MAGIC_BITMASK, ofs, 
481                                      je16_to_cpu(node->magic));
482                         DIRTY_SPACE(4);
483                         ofs += 4;
484                         continue;
485                 }
486                 /* We seem to have a node of sorts. Check the CRC */
487                 crcnode.magic = node->magic;
488                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
489                 crcnode.totlen = node->totlen;
490                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
491
492                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
493                         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",
494                                      ofs, je16_to_cpu(node->magic),
495                                      je16_to_cpu(node->nodetype), 
496                                      je32_to_cpu(node->totlen),
497                                      je32_to_cpu(node->hdr_crc),
498                                      hdr_crc);
499                         DIRTY_SPACE(4);
500                         ofs += 4;
501                         continue;
502                 }
503
504                 if (ofs + je32_to_cpu(node->totlen) > 
505                     jeb->offset + c->sector_size) {
506                         /* Eep. Node goes over the end of the erase block. */
507                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
508                                ofs, je32_to_cpu(node->totlen));
509                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
510                         DIRTY_SPACE(4);
511                         ofs += 4;
512                         continue;
513                 }
514
515                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
516                         /* Wheee. This is an obsoleted node */
517                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
518                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
519                         ofs += PAD(je32_to_cpu(node->totlen));
520                         continue;
521                 }
522
523                 switch(je16_to_cpu(node->nodetype)) {
524                 case JFFS2_NODETYPE_INODE:
525                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
526                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
527                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
528                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
529                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
530                                 if (err)
531                                         return err;
532                                 buf_ofs = ofs;
533                                 node = (void *)buf;
534                         }
535                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs);
536                         if (err) return err;
537                         ofs += PAD(je32_to_cpu(node->totlen));
538                         break;
539                         
540                 case JFFS2_NODETYPE_DIRENT:
541                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
542                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
543                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
544                                           je32_to_cpu(node->totlen), buf_len, ofs));
545                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
546                                 if (err)
547                                         return err;
548                                 buf_ofs = ofs;
549                                 node = (void *)buf;
550                         }
551                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs);
552                         if (err) return err;
553                         ofs += PAD(je32_to_cpu(node->totlen));
554                         break;
555
556                 case JFFS2_NODETYPE_CLEANMARKER:
557                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
558                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
559                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n", 
560                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
561                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
562                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
563                         } else if (jeb->first_node) {
564                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
565                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
566                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
567                         } else {
568                                 struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
569                                 if (!marker_ref) {
570                                         printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
571                                         return -ENOMEM;
572                                 }
573                                 marker_ref->next_in_ino = NULL;
574                                 marker_ref->next_phys = NULL;
575                                 marker_ref->flash_offset = ofs | REF_NORMAL;
576                                 marker_ref->__totlen = c->cleanmarker_size;
577                                 jeb->first_node = jeb->last_node = marker_ref;
578                              
579                                 USED_SPACE(PAD(c->cleanmarker_size));
580                                 ofs += PAD(c->cleanmarker_size);
581                         }
582                         break;
583
584                 case JFFS2_NODETYPE_PADDING:
585                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
586                         ofs += PAD(je32_to_cpu(node->totlen));
587                         break;
588
589                 default:
590                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
591                         case JFFS2_FEATURE_ROCOMPAT:
592                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
593                                 c->flags |= JFFS2_SB_FLAG_RO;
594                                 if (!(jffs2_is_readonly(c)))
595                                         return -EROFS;
596                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
597                                 ofs += PAD(je32_to_cpu(node->totlen));
598                                 break;
599
600                         case JFFS2_FEATURE_INCOMPAT:
601                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
602                                 return -EINVAL;
603
604                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
605                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
606                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
607                                 ofs += PAD(je32_to_cpu(node->totlen));
608                                 break;
609
610                         case JFFS2_FEATURE_RWCOMPAT_COPY:
611                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
612                                 USED_SPACE(PAD(je32_to_cpu(node->totlen)));
613                                 ofs += PAD(je32_to_cpu(node->totlen));
614                                 break;
615                         }
616                 }
617         }
618
619
620         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset, 
621                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
622
623         /* mark_node_obsolete can add to wasted !! */
624         if (jeb->wasted_size) {
625                 jeb->dirty_size += jeb->wasted_size;
626                 c->dirty_size += jeb->wasted_size;
627                 c->wasted_size -= jeb->wasted_size;
628                 jeb->wasted_size = 0;
629         }
630
631         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size 
632                 && (!jeb->first_node || !jeb->first_node->next_phys) )
633                 return BLK_STATE_CLEANMARKER;
634                 
635         /* move blocks with max 4 byte dirty space to cleanlist */      
636         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
637                 c->dirty_size -= jeb->dirty_size;
638                 c->wasted_size += jeb->dirty_size; 
639                 jeb->wasted_size += jeb->dirty_size;
640                 jeb->dirty_size = 0;
641                 return BLK_STATE_CLEAN;
642         } else if (jeb->used_size || jeb->unchecked_size)
643                 return BLK_STATE_PARTDIRTY;
644         else
645                 return BLK_STATE_ALLDIRTY;
646 }
647
648 static struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
649 {
650         struct jffs2_inode_cache *ic;
651
652         ic = jffs2_get_ino_cache(c, ino);
653         if (ic)
654                 return ic;
655
656         if (ino > c->highest_ino)
657                 c->highest_ino = ino;
658
659         ic = jffs2_alloc_inode_cache();
660         if (!ic) {
661                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
662                 return NULL;
663         }
664         memset(ic, 0, sizeof(*ic));
665
666         ic->ino = ino;
667         ic->nodes = (void *)ic;
668         jffs2_add_ino_cache(c, ic);
669         if (ino == 1)
670                 ic->nlink = 1;
671         return ic;
672 }
673
674 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 
675                                  struct jffs2_raw_inode *ri, uint32_t ofs)
676 {
677         struct jffs2_raw_node_ref *raw;
678         struct jffs2_inode_cache *ic;
679         uint32_t ino = je32_to_cpu(ri->ino);
680
681         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
682
683         /* We do very little here now. Just check the ino# to which we should attribute
684            this node; we can do all the CRC checking etc. later. There's a tradeoff here -- 
685            we used to scan the flash once only, reading everything we want from it into
686            memory, then building all our in-core data structures and freeing the extra
687            information. Now we allow the first part of the mount to complete a lot quicker,
688            but we have to go _back_ to the flash in order to finish the CRC checking, etc. 
689            Which means that the _full_ amount of time to get to proper write mode with GC
690            operational may actually be _longer_ than before. Sucks to be me. */
691
692         raw = jffs2_alloc_raw_node_ref();
693         if (!raw) {
694                 printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node reference failed\n");
695                 return -ENOMEM;
696         }
697
698         ic = jffs2_get_ino_cache(c, ino);
699         if (!ic) {
700                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
701                    first node we found for this inode. Do a CRC check to protect against the former
702                    case */
703                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
704
705                 if (crc != je32_to_cpu(ri->node_crc)) {
706                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
707                                ofs, je32_to_cpu(ri->node_crc), crc);
708                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
709                         DIRTY_SPACE(PAD(je32_to_cpu(ri->totlen)));
710                         jffs2_free_raw_node_ref(raw);
711                         return 0;
712                 }
713                 ic = jffs2_scan_make_ino_cache(c, ino);
714                 if (!ic) {
715                         jffs2_free_raw_node_ref(raw);
716                         return -ENOMEM;
717                 }
718         }
719
720         /* Wheee. It worked */
721
722         raw->flash_offset = ofs | REF_UNCHECKED;
723         raw->__totlen = PAD(je32_to_cpu(ri->totlen));
724         raw->next_phys = NULL;
725         raw->next_in_ino = ic->nodes;
726
727         ic->nodes = raw;
728         if (!jeb->first_node)
729                 jeb->first_node = raw;
730         if (jeb->last_node)
731                 jeb->last_node->next_phys = raw;
732         jeb->last_node = raw;
733
734         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n", 
735                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
736                   je32_to_cpu(ri->offset),
737                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
738
739         pseudo_random += je32_to_cpu(ri->version);
740
741         UNCHECKED_SPACE(PAD(je32_to_cpu(ri->totlen)));
742         return 0;
743 }
744
745 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 
746                                   struct jffs2_raw_dirent *rd, uint32_t ofs)
747 {
748         struct jffs2_raw_node_ref *raw;
749         struct jffs2_full_dirent *fd;
750         struct jffs2_inode_cache *ic;
751         uint32_t crc;
752
753         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
754
755         /* We don't get here unless the node is still valid, so we don't have to
756            mask in the ACCURATE bit any more. */
757         crc = crc32(0, rd, sizeof(*rd)-8);
758
759         if (crc != je32_to_cpu(rd->node_crc)) {
760                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
761                        ofs, je32_to_cpu(rd->node_crc), crc);
762                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
763                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
764                 return 0;
765         }
766
767         pseudo_random += je32_to_cpu(rd->version);
768
769         fd = jffs2_alloc_full_dirent(rd->nsize+1);
770         if (!fd) {
771                 return -ENOMEM;
772         }
773         memcpy(&fd->name, rd->name, rd->nsize);
774         fd->name[rd->nsize] = 0;
775
776         crc = crc32(0, fd->name, rd->nsize);
777         if (crc != je32_to_cpu(rd->name_crc)) {
778                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
779                        ofs, je32_to_cpu(rd->name_crc), crc);    
780                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
781                 jffs2_free_full_dirent(fd);
782                 /* FIXME: Why do we believe totlen? */
783                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
784                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
785                 return 0;
786         }
787         raw = jffs2_alloc_raw_node_ref();
788         if (!raw) {
789                 jffs2_free_full_dirent(fd);
790                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node reference failed\n");
791                 return -ENOMEM;
792         }
793         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
794         if (!ic) {
795                 jffs2_free_full_dirent(fd);
796                 jffs2_free_raw_node_ref(raw);
797                 return -ENOMEM;
798         }
799         
800         raw->__totlen = PAD(je32_to_cpu(rd->totlen));
801         raw->flash_offset = ofs | REF_PRISTINE;
802         raw->next_phys = NULL;
803         raw->next_in_ino = ic->nodes;
804         ic->nodes = raw;
805         if (!jeb->first_node)
806                 jeb->first_node = raw;
807         if (jeb->last_node)
808                 jeb->last_node->next_phys = raw;
809         jeb->last_node = raw;
810
811         fd->raw = raw;
812         fd->next = NULL;
813         fd->version = je32_to_cpu(rd->version);
814         fd->ino = je32_to_cpu(rd->ino);
815         fd->nhash = full_name_hash(fd->name, rd->nsize);
816         fd->type = rd->type;
817         USED_SPACE(PAD(je32_to_cpu(rd->totlen)));
818         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
819
820         return 0;
821 }
822
823 static int count_list(struct list_head *l)
824 {
825         uint32_t count = 0;
826         struct list_head *tmp;
827
828         list_for_each(tmp, l) {
829                 count++;
830         }
831         return count;
832 }
833
834 /* Note: This breaks if list_empty(head). I don't care. You
835    might, if you copy this code and use it elsewhere :) */
836 static void rotate_list(struct list_head *head, uint32_t count)
837 {
838         struct list_head *n = head->next;
839
840         list_del(head);
841         while(count--) {
842                 n = n->next;
843         }
844         list_add(head, n);
845 }
846
847 void jffs2_rotate_lists(struct jffs2_sb_info *c)
848 {
849         uint32_t x;
850         uint32_t rotateby;
851
852         x = count_list(&c->clean_list);
853         if (x) {
854                 rotateby = pseudo_random % x;
855                 D1(printk(KERN_DEBUG "Rotating clean_list by %d\n", rotateby));
856
857                 rotate_list((&c->clean_list), rotateby);
858
859                 D1(printk(KERN_DEBUG "Erase block at front of clean_list is at %08x\n",
860                           list_entry(c->clean_list.next, struct jffs2_eraseblock, list)->offset));
861         } else {
862                 D1(printk(KERN_DEBUG "Not rotating empty clean_list\n"));
863         }
864
865         x = count_list(&c->very_dirty_list);
866         if (x) {
867                 rotateby = pseudo_random % x;
868                 D1(printk(KERN_DEBUG "Rotating very_dirty_list by %d\n", rotateby));
869
870                 rotate_list((&c->very_dirty_list), rotateby);
871
872                 D1(printk(KERN_DEBUG "Erase block at front of very_dirty_list is at %08x\n",
873                           list_entry(c->very_dirty_list.next, struct jffs2_eraseblock, list)->offset));
874         } else {
875                 D1(printk(KERN_DEBUG "Not rotating empty very_dirty_list\n"));
876         }
877
878         x = count_list(&c->dirty_list);
879         if (x) {
880                 rotateby = pseudo_random % x;
881                 D1(printk(KERN_DEBUG "Rotating dirty_list by %d\n", rotateby));
882
883                 rotate_list((&c->dirty_list), rotateby);
884
885                 D1(printk(KERN_DEBUG "Erase block at front of dirty_list is at %08x\n",
886                           list_entry(c->dirty_list.next, struct jffs2_eraseblock, list)->offset));
887         } else {
888                 D1(printk(KERN_DEBUG "Not rotating empty dirty_list\n"));
889         }
890
891         x = count_list(&c->erasable_list);
892         if (x) {
893                 rotateby = pseudo_random % x;
894                 D1(printk(KERN_DEBUG "Rotating erasable_list by %d\n", rotateby));
895
896                 rotate_list((&c->erasable_list), rotateby);
897
898                 D1(printk(KERN_DEBUG "Erase block at front of erasable_list is at %08x\n",
899                           list_entry(c->erasable_list.next, struct jffs2_eraseblock, list)->offset));
900         } else {
901                 D1(printk(KERN_DEBUG "Not rotating empty erasable_list\n"));
902         }
903
904         if (c->nr_erasing_blocks) {
905                 rotateby = pseudo_random % c->nr_erasing_blocks;
906                 D1(printk(KERN_DEBUG "Rotating erase_pending_list by %d\n", rotateby));
907
908                 rotate_list((&c->erase_pending_list), rotateby);
909
910                 D1(printk(KERN_DEBUG "Erase block at front of erase_pending_list is at %08x\n",
911                           list_entry(c->erase_pending_list.next, struct jffs2_eraseblock, list)->offset));
912         } else {
913                 D1(printk(KERN_DEBUG "Not rotating empty erase_pending_list\n"));
914         }
915
916         if (c->nr_free_blocks) {
917                 rotateby = pseudo_random % c->nr_free_blocks;
918                 D1(printk(KERN_DEBUG "Rotating free_list by %d\n", rotateby));
919
920                 rotate_list((&c->free_list), rotateby);
921
922                 D1(printk(KERN_DEBUG "Erase block at front of free_list is at %08x\n",
923                           list_entry(c->free_list.next, struct jffs2_eraseblock, list)->offset));
924         } else {
925                 D1(printk(KERN_DEBUG "Not rotating empty free_list\n"));
926         }
927 }