Linux-2.6.12-rc2
[linux-3.10.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 1.115 2004/11/17 12:59:08 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 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 #if defined CONFIG_JFFS2_FS_NAND || defined CONFIG_JFFS2_FS_NOR_ECC
72         if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
73                 return c->wbuf_pagesize;
74 #endif
75         return min;
76
77 }
78 int jffs2_scan_medium(struct jffs2_sb_info *c)
79 {
80         int i, ret;
81         uint32_t empty_blocks = 0, bad_blocks = 0;
82         unsigned char *flashbuf = NULL;
83         uint32_t buf_size = 0;
84 #ifndef __ECOS
85         size_t pointlen;
86
87         if (c->mtd->point) {
88                 ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
89                 if (!ret && pointlen < c->mtd->size) {
90                         /* Don't muck about if it won't let us point to the whole flash */
91                         D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
92                         c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
93                         flashbuf = NULL;
94                 }
95                 if (ret)
96                         D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
97         }
98 #endif
99         if (!flashbuf) {
100                 /* For NAND it's quicker to read a whole eraseblock at a time,
101                    apparently */
102                 if (jffs2_cleanmarker_oob(c))
103                         buf_size = c->sector_size;
104                 else
105                         buf_size = PAGE_SIZE;
106
107                 /* Respect kmalloc limitations */
108                 if (buf_size > 128*1024)
109                         buf_size = 128*1024;
110
111                 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
112                 flashbuf = kmalloc(buf_size, GFP_KERNEL);
113                 if (!flashbuf)
114                         return -ENOMEM;
115         }
116
117         for (i=0; i<c->nr_blocks; i++) {
118                 struct jffs2_eraseblock *jeb = &c->blocks[i];
119
120                 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset), buf_size);
121
122                 if (ret < 0)
123                         goto out;
124
125                 ACCT_PARANOIA_CHECK(jeb);
126
127                 /* Now decide which list to put it on */
128                 switch(ret) {
129                 case BLK_STATE_ALLFF:
130                         /* 
131                          * Empty block.   Since we can't be sure it 
132                          * was entirely erased, we just queue it for erase
133                          * again.  It will be marked as such when the erase
134                          * is complete.  Meanwhile we still count it as empty
135                          * for later checks.
136                          */
137                         empty_blocks++;
138                         list_add(&jeb->list, &c->erase_pending_list);
139                         c->nr_erasing_blocks++;
140                         break;
141
142                 case BLK_STATE_CLEANMARKER:
143                         /* Only a CLEANMARKER node is valid */
144                         if (!jeb->dirty_size) {
145                                 /* It's actually free */
146                                 list_add(&jeb->list, &c->free_list);
147                                 c->nr_free_blocks++;
148                         } else {
149                                 /* Dirt */
150                                 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
151                                 list_add(&jeb->list, &c->erase_pending_list);
152                                 c->nr_erasing_blocks++;
153                         }
154                         break;
155
156                 case BLK_STATE_CLEAN:
157                         /* Full (or almost full) of clean data. Clean list */
158                         list_add(&jeb->list, &c->clean_list);
159                         break;
160
161                 case BLK_STATE_PARTDIRTY:
162                         /* Some data, but not full. Dirty list. */
163                         /* We want to remember the block with most free space
164                            and stick it in the 'nextblock' position to start writing to it. */
165                         if (jeb->free_size > min_free(c) && 
166                             (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
167                                 /* Better candidate for the next writes to go to */
168                                 if (c->nextblock) {
169                                         c->nextblock->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
170                                         c->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
171                                         c->free_size -= c->nextblock->free_size;
172                                         c->wasted_size -= c->nextblock->wasted_size;
173                                         c->nextblock->free_size = c->nextblock->wasted_size = 0;
174                                         if (VERYDIRTY(c, c->nextblock->dirty_size)) {
175                                                 list_add(&c->nextblock->list, &c->very_dirty_list);
176                                         } else {
177                                                 list_add(&c->nextblock->list, &c->dirty_list);
178                                         }
179                                 }
180                                 c->nextblock = jeb;
181                         } else {
182                                 jeb->dirty_size += jeb->free_size + jeb->wasted_size;
183                                 c->dirty_size += jeb->free_size + jeb->wasted_size;
184                                 c->free_size -= jeb->free_size;
185                                 c->wasted_size -= jeb->wasted_size;
186                                 jeb->free_size = jeb->wasted_size = 0;
187                                 if (VERYDIRTY(c, jeb->dirty_size)) {
188                                         list_add(&jeb->list, &c->very_dirty_list);
189                                 } else {
190                                         list_add(&jeb->list, &c->dirty_list);
191                                 }
192                         }
193                         break;
194
195                 case BLK_STATE_ALLDIRTY:
196                         /* Nothing valid - not even a clean marker. Needs erasing. */
197                         /* For now we just put it on the erasing list. We'll start the erases later */
198                         D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
199                         list_add(&jeb->list, &c->erase_pending_list);
200                         c->nr_erasing_blocks++;
201                         break;
202                         
203                 case BLK_STATE_BADBLOCK:
204                         D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
205                         list_add(&jeb->list, &c->bad_list);
206                         c->bad_size += c->sector_size;
207                         c->free_size -= c->sector_size;
208                         bad_blocks++;
209                         break;
210                 default:
211                         printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
212                         BUG();  
213                 }
214         }
215         
216         /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
217         if (c->nextblock && (c->nextblock->dirty_size)) {
218                 c->nextblock->wasted_size += c->nextblock->dirty_size;
219                 c->wasted_size += c->nextblock->dirty_size;
220                 c->dirty_size -= c->nextblock->dirty_size;
221                 c->nextblock->dirty_size = 0;
222         }
223 #if defined CONFIG_JFFS2_FS_NAND || defined CONFIG_JFFS2_FS_NOR_ECC
224         if (!jffs2_can_mark_obsolete(c) && c->nextblock && (c->nextblock->free_size & (c->wbuf_pagesize-1))) {
225                 /* If we're going to start writing into a block which already 
226                    contains data, and the end of the data isn't page-aligned,
227                    skip a little and align it. */
228
229                 uint32_t skip = c->nextblock->free_size & (c->wbuf_pagesize-1);
230
231                 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
232                           skip));
233                 c->nextblock->wasted_size += skip;
234                 c->wasted_size += skip;
235
236                 c->nextblock->free_size -= skip;
237                 c->free_size -= skip;
238         }
239 #endif
240         if (c->nr_erasing_blocks) {
241                 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) { 
242                         printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
243                         printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
244                         ret = -EIO;
245                         goto out;
246                 }
247                 jffs2_erase_pending_trigger(c);
248         }
249         ret = 0;
250  out:
251         if (buf_size)
252                 kfree(flashbuf);
253 #ifndef __ECOS
254         else 
255                 c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
256 #endif
257         return ret;
258 }
259
260 static int jffs2_fill_scan_buf (struct jffs2_sb_info *c, unsigned char *buf,
261                                 uint32_t ofs, uint32_t len)
262 {
263         int ret;
264         size_t retlen;
265
266         ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
267         if (ret) {
268                 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
269                 return ret;
270         }
271         if (retlen < len) {
272                 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
273                 return -EIO;
274         }
275         D2(printk(KERN_DEBUG "Read 0x%x bytes from 0x%08x into buf\n", len, ofs));
276         D2(printk(KERN_DEBUG "000: %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
277                   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]));
278         return 0;
279 }
280
281 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
282                                   unsigned char *buf, uint32_t buf_size) {
283         struct jffs2_unknown_node *node;
284         struct jffs2_unknown_node crcnode;
285         uint32_t ofs, prevofs;
286         uint32_t hdr_crc, buf_ofs, buf_len;
287         int err;
288         int noise = 0;
289 #ifdef CONFIG_JFFS2_FS_NAND
290         int cleanmarkerfound = 0;
291 #endif
292
293         ofs = jeb->offset;
294         prevofs = jeb->offset - 1;
295
296         D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));
297
298 #ifdef CONFIG_JFFS2_FS_NAND
299         if (jffs2_cleanmarker_oob(c)) {
300                 int ret = jffs2_check_nand_cleanmarker(c, jeb);
301                 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
302                 /* Even if it's not found, we still scan to see
303                    if the block is empty. We use this information
304                    to decide whether to erase it or not. */
305                 switch (ret) {
306                 case 0:         cleanmarkerfound = 1; break;
307                 case 1:         break;
308                 case 2:         return BLK_STATE_BADBLOCK;
309                 case 3:         return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
310                 default:        return ret;
311                 }
312         }
313 #endif
314         buf_ofs = jeb->offset;
315
316         if (!buf_size) {
317                 buf_len = c->sector_size;
318         } else {
319                 buf_len = EMPTY_SCAN_SIZE;
320                 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
321                 if (err)
322                         return err;
323         }
324         
325         /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
326         ofs = 0;
327
328         /* Scan only 4KiB of 0xFF before declaring it's empty */
329         while(ofs < EMPTY_SCAN_SIZE && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
330                 ofs += 4;
331
332         if (ofs == EMPTY_SCAN_SIZE) {
333 #ifdef CONFIG_JFFS2_FS_NAND
334                 if (jffs2_cleanmarker_oob(c)) {
335                         /* scan oob, take care of cleanmarker */
336                         int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
337                         D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
338                         switch (ret) {
339                         case 0:         return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
340                         case 1:         return BLK_STATE_ALLDIRTY;
341                         default:        return ret;
342                         }
343                 }
344 #endif
345                 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
346                 return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
347         }
348         if (ofs) {
349                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
350                           jeb->offset + ofs));
351                 DIRTY_SPACE(ofs);
352         }
353
354         /* Now ofs is a complete physical flash offset as it always was... */
355         ofs += jeb->offset;
356
357         noise = 10;
358
359 scan_more:      
360         while(ofs < jeb->offset + c->sector_size) {
361
362                 D1(ACCT_PARANOIA_CHECK(jeb));
363
364                 cond_resched();
365
366                 if (ofs & 3) {
367                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
368                         ofs = PAD(ofs);
369                         continue;
370                 }
371                 if (ofs == prevofs) {
372                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
373                         DIRTY_SPACE(4);
374                         ofs += 4;
375                         continue;
376                 }
377                 prevofs = ofs;
378
379                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
380                         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),
381                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
382                         DIRTY_SPACE((jeb->offset + c->sector_size)-ofs);
383                         break;
384                 }
385
386                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
387                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
388                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
389                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
390                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
391                         if (err)
392                                 return err;
393                         buf_ofs = ofs;
394                 }
395
396                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
397
398                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
399                         uint32_t inbuf_ofs;
400                         uint32_t empty_start;
401
402                         empty_start = ofs;
403                         ofs += 4;
404
405                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
406                 more_empty:
407                         inbuf_ofs = ofs - buf_ofs;
408                         while (inbuf_ofs < buf_len) {
409                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
410                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
411                                                empty_start, ofs);
412                                         DIRTY_SPACE(ofs-empty_start);
413                                         goto scan_more;
414                                 }
415
416                                 inbuf_ofs+=4;
417                                 ofs += 4;
418                         }
419                         /* Ran off end. */
420                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
421
422                         /* If we're only checking the beginning of a block with a cleanmarker,
423                            bail now */
424                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) && 
425                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_in_ino) {
426                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE));
427                                 return BLK_STATE_CLEANMARKER;
428                         }
429
430                         /* See how much more there is to read in this eraseblock... */
431                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
432                         if (!buf_len) {
433                                 /* No more to read. Break out of main loop without marking 
434                                    this range of empty space as dirty (because it's not) */
435                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
436                                           empty_start));
437                                 break;
438                         }
439                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
440                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
441                         if (err)
442                                 return err;
443                         buf_ofs = ofs;
444                         goto more_empty;
445                 }
446
447                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
448                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
449                         DIRTY_SPACE(4);
450                         ofs += 4;
451                         continue;
452                 }
453                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
454                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
455                         DIRTY_SPACE(4);
456                         ofs += 4;
457                         continue;
458                 }
459                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
460                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
461                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
462                         DIRTY_SPACE(4);
463                         ofs += 4;
464                         continue;
465                 }
466                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
467                         /* OK. We're out of possibilities. Whinge and move on */
468                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n", 
469                                      JFFS2_MAGIC_BITMASK, ofs, 
470                                      je16_to_cpu(node->magic));
471                         DIRTY_SPACE(4);
472                         ofs += 4;
473                         continue;
474                 }
475                 /* We seem to have a node of sorts. Check the CRC */
476                 crcnode.magic = node->magic;
477                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
478                 crcnode.totlen = node->totlen;
479                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
480
481                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
482                         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",
483                                      ofs, je16_to_cpu(node->magic),
484                                      je16_to_cpu(node->nodetype), 
485                                      je32_to_cpu(node->totlen),
486                                      je32_to_cpu(node->hdr_crc),
487                                      hdr_crc);
488                         DIRTY_SPACE(4);
489                         ofs += 4;
490                         continue;
491                 }
492
493                 if (ofs + je32_to_cpu(node->totlen) > 
494                     jeb->offset + c->sector_size) {
495                         /* Eep. Node goes over the end of the erase block. */
496                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
497                                ofs, je32_to_cpu(node->totlen));
498                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
499                         DIRTY_SPACE(4);
500                         ofs += 4;
501                         continue;
502                 }
503
504                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
505                         /* Wheee. This is an obsoleted node */
506                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
507                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
508                         ofs += PAD(je32_to_cpu(node->totlen));
509                         continue;
510                 }
511
512                 switch(je16_to_cpu(node->nodetype)) {
513                 case JFFS2_NODETYPE_INODE:
514                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
515                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
516                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
517                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
518                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
519                                 if (err)
520                                         return err;
521                                 buf_ofs = ofs;
522                                 node = (void *)buf;
523                         }
524                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs);
525                         if (err) return err;
526                         ofs += PAD(je32_to_cpu(node->totlen));
527                         break;
528                         
529                 case JFFS2_NODETYPE_DIRENT:
530                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
531                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
532                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
533                                           je32_to_cpu(node->totlen), buf_len, ofs));
534                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
535                                 if (err)
536                                         return err;
537                                 buf_ofs = ofs;
538                                 node = (void *)buf;
539                         }
540                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs);
541                         if (err) return err;
542                         ofs += PAD(je32_to_cpu(node->totlen));
543                         break;
544
545                 case JFFS2_NODETYPE_CLEANMARKER:
546                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
547                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
548                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n", 
549                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
550                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
551                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
552                         } else if (jeb->first_node) {
553                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
554                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
555                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
556                         } else {
557                                 struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
558                                 if (!marker_ref) {
559                                         printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
560                                         return -ENOMEM;
561                                 }
562                                 marker_ref->next_in_ino = NULL;
563                                 marker_ref->next_phys = NULL;
564                                 marker_ref->flash_offset = ofs | REF_NORMAL;
565                                 marker_ref->__totlen = c->cleanmarker_size;
566                                 jeb->first_node = jeb->last_node = marker_ref;
567                              
568                                 USED_SPACE(PAD(c->cleanmarker_size));
569                                 ofs += PAD(c->cleanmarker_size);
570                         }
571                         break;
572
573                 case JFFS2_NODETYPE_PADDING:
574                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
575                         ofs += PAD(je32_to_cpu(node->totlen));
576                         break;
577
578                 default:
579                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
580                         case JFFS2_FEATURE_ROCOMPAT:
581                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
582                                 c->flags |= JFFS2_SB_FLAG_RO;
583                                 if (!(jffs2_is_readonly(c)))
584                                         return -EROFS;
585                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
586                                 ofs += PAD(je32_to_cpu(node->totlen));
587                                 break;
588
589                         case JFFS2_FEATURE_INCOMPAT:
590                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
591                                 return -EINVAL;
592
593                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
594                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
595                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
596                                 ofs += PAD(je32_to_cpu(node->totlen));
597                                 break;
598
599                         case JFFS2_FEATURE_RWCOMPAT_COPY:
600                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
601                                 USED_SPACE(PAD(je32_to_cpu(node->totlen)));
602                                 ofs += PAD(je32_to_cpu(node->totlen));
603                                 break;
604                         }
605                 }
606         }
607
608
609         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset, 
610                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
611
612         /* mark_node_obsolete can add to wasted !! */
613         if (jeb->wasted_size) {
614                 jeb->dirty_size += jeb->wasted_size;
615                 c->dirty_size += jeb->wasted_size;
616                 c->wasted_size -= jeb->wasted_size;
617                 jeb->wasted_size = 0;
618         }
619
620         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size 
621                 && (!jeb->first_node || !jeb->first_node->next_in_ino) )
622                 return BLK_STATE_CLEANMARKER;
623                 
624         /* move blocks with max 4 byte dirty space to cleanlist */      
625         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
626                 c->dirty_size -= jeb->dirty_size;
627                 c->wasted_size += jeb->dirty_size; 
628                 jeb->wasted_size += jeb->dirty_size;
629                 jeb->dirty_size = 0;
630                 return BLK_STATE_CLEAN;
631         } else if (jeb->used_size || jeb->unchecked_size)
632                 return BLK_STATE_PARTDIRTY;
633         else
634                 return BLK_STATE_ALLDIRTY;
635 }
636
637 static struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
638 {
639         struct jffs2_inode_cache *ic;
640
641         ic = jffs2_get_ino_cache(c, ino);
642         if (ic)
643                 return ic;
644
645         if (ino > c->highest_ino)
646                 c->highest_ino = ino;
647
648         ic = jffs2_alloc_inode_cache();
649         if (!ic) {
650                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
651                 return NULL;
652         }
653         memset(ic, 0, sizeof(*ic));
654
655         ic->ino = ino;
656         ic->nodes = (void *)ic;
657         jffs2_add_ino_cache(c, ic);
658         if (ino == 1)
659                 ic->nlink = 1;
660         return ic;
661 }
662
663 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 
664                                  struct jffs2_raw_inode *ri, uint32_t ofs)
665 {
666         struct jffs2_raw_node_ref *raw;
667         struct jffs2_inode_cache *ic;
668         uint32_t ino = je32_to_cpu(ri->ino);
669
670         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
671
672         /* We do very little here now. Just check the ino# to which we should attribute
673            this node; we can do all the CRC checking etc. later. There's a tradeoff here -- 
674            we used to scan the flash once only, reading everything we want from it into
675            memory, then building all our in-core data structures and freeing the extra
676            information. Now we allow the first part of the mount to complete a lot quicker,
677            but we have to go _back_ to the flash in order to finish the CRC checking, etc. 
678            Which means that the _full_ amount of time to get to proper write mode with GC
679            operational may actually be _longer_ than before. Sucks to be me. */
680
681         raw = jffs2_alloc_raw_node_ref();
682         if (!raw) {
683                 printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node reference failed\n");
684                 return -ENOMEM;
685         }
686
687         ic = jffs2_get_ino_cache(c, ino);
688         if (!ic) {
689                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
690                    first node we found for this inode. Do a CRC check to protect against the former
691                    case */
692                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
693
694                 if (crc != je32_to_cpu(ri->node_crc)) {
695                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
696                                ofs, je32_to_cpu(ri->node_crc), crc);
697                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
698                         DIRTY_SPACE(PAD(je32_to_cpu(ri->totlen)));
699                         jffs2_free_raw_node_ref(raw);
700                         return 0;
701                 }
702                 ic = jffs2_scan_make_ino_cache(c, ino);
703                 if (!ic) {
704                         jffs2_free_raw_node_ref(raw);
705                         return -ENOMEM;
706                 }
707         }
708
709         /* Wheee. It worked */
710
711         raw->flash_offset = ofs | REF_UNCHECKED;
712         raw->__totlen = PAD(je32_to_cpu(ri->totlen));
713         raw->next_phys = NULL;
714         raw->next_in_ino = ic->nodes;
715
716         ic->nodes = raw;
717         if (!jeb->first_node)
718                 jeb->first_node = raw;
719         if (jeb->last_node)
720                 jeb->last_node->next_phys = raw;
721         jeb->last_node = raw;
722
723         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n", 
724                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
725                   je32_to_cpu(ri->offset),
726                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
727
728         pseudo_random += je32_to_cpu(ri->version);
729
730         UNCHECKED_SPACE(PAD(je32_to_cpu(ri->totlen)));
731         return 0;
732 }
733
734 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 
735                                   struct jffs2_raw_dirent *rd, uint32_t ofs)
736 {
737         struct jffs2_raw_node_ref *raw;
738         struct jffs2_full_dirent *fd;
739         struct jffs2_inode_cache *ic;
740         uint32_t crc;
741
742         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
743
744         /* We don't get here unless the node is still valid, so we don't have to
745            mask in the ACCURATE bit any more. */
746         crc = crc32(0, rd, sizeof(*rd)-8);
747
748         if (crc != je32_to_cpu(rd->node_crc)) {
749                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
750                        ofs, je32_to_cpu(rd->node_crc), crc);
751                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
752                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
753                 return 0;
754         }
755
756         pseudo_random += je32_to_cpu(rd->version);
757
758         fd = jffs2_alloc_full_dirent(rd->nsize+1);
759         if (!fd) {
760                 return -ENOMEM;
761         }
762         memcpy(&fd->name, rd->name, rd->nsize);
763         fd->name[rd->nsize] = 0;
764
765         crc = crc32(0, fd->name, rd->nsize);
766         if (crc != je32_to_cpu(rd->name_crc)) {
767                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
768                        ofs, je32_to_cpu(rd->name_crc), crc);    
769                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
770                 jffs2_free_full_dirent(fd);
771                 /* FIXME: Why do we believe totlen? */
772                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
773                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
774                 return 0;
775         }
776         raw = jffs2_alloc_raw_node_ref();
777         if (!raw) {
778                 jffs2_free_full_dirent(fd);
779                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node reference failed\n");
780                 return -ENOMEM;
781         }
782         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
783         if (!ic) {
784                 jffs2_free_full_dirent(fd);
785                 jffs2_free_raw_node_ref(raw);
786                 return -ENOMEM;
787         }
788         
789         raw->__totlen = PAD(je32_to_cpu(rd->totlen));
790         raw->flash_offset = ofs | REF_PRISTINE;
791         raw->next_phys = NULL;
792         raw->next_in_ino = ic->nodes;
793         ic->nodes = raw;
794         if (!jeb->first_node)
795                 jeb->first_node = raw;
796         if (jeb->last_node)
797                 jeb->last_node->next_phys = raw;
798         jeb->last_node = raw;
799
800         fd->raw = raw;
801         fd->next = NULL;
802         fd->version = je32_to_cpu(rd->version);
803         fd->ino = je32_to_cpu(rd->ino);
804         fd->nhash = full_name_hash(fd->name, rd->nsize);
805         fd->type = rd->type;
806         USED_SPACE(PAD(je32_to_cpu(rd->totlen)));
807         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
808
809         return 0;
810 }
811
812 static int count_list(struct list_head *l)
813 {
814         uint32_t count = 0;
815         struct list_head *tmp;
816
817         list_for_each(tmp, l) {
818                 count++;
819         }
820         return count;
821 }
822
823 /* Note: This breaks if list_empty(head). I don't care. You
824    might, if you copy this code and use it elsewhere :) */
825 static void rotate_list(struct list_head *head, uint32_t count)
826 {
827         struct list_head *n = head->next;
828
829         list_del(head);
830         while(count--) {
831                 n = n->next;
832         }
833         list_add(head, n);
834 }
835
836 void jffs2_rotate_lists(struct jffs2_sb_info *c)
837 {
838         uint32_t x;
839         uint32_t rotateby;
840
841         x = count_list(&c->clean_list);
842         if (x) {
843                 rotateby = pseudo_random % x;
844                 D1(printk(KERN_DEBUG "Rotating clean_list by %d\n", rotateby));
845
846                 rotate_list((&c->clean_list), rotateby);
847
848                 D1(printk(KERN_DEBUG "Erase block at front of clean_list is at %08x\n",
849                           list_entry(c->clean_list.next, struct jffs2_eraseblock, list)->offset));
850         } else {
851                 D1(printk(KERN_DEBUG "Not rotating empty clean_list\n"));
852         }
853
854         x = count_list(&c->very_dirty_list);
855         if (x) {
856                 rotateby = pseudo_random % x;
857                 D1(printk(KERN_DEBUG "Rotating very_dirty_list by %d\n", rotateby));
858
859                 rotate_list((&c->very_dirty_list), rotateby);
860
861                 D1(printk(KERN_DEBUG "Erase block at front of very_dirty_list is at %08x\n",
862                           list_entry(c->very_dirty_list.next, struct jffs2_eraseblock, list)->offset));
863         } else {
864                 D1(printk(KERN_DEBUG "Not rotating empty very_dirty_list\n"));
865         }
866
867         x = count_list(&c->dirty_list);
868         if (x) {
869                 rotateby = pseudo_random % x;
870                 D1(printk(KERN_DEBUG "Rotating dirty_list by %d\n", rotateby));
871
872                 rotate_list((&c->dirty_list), rotateby);
873
874                 D1(printk(KERN_DEBUG "Erase block at front of dirty_list is at %08x\n",
875                           list_entry(c->dirty_list.next, struct jffs2_eraseblock, list)->offset));
876         } else {
877                 D1(printk(KERN_DEBUG "Not rotating empty dirty_list\n"));
878         }
879
880         x = count_list(&c->erasable_list);
881         if (x) {
882                 rotateby = pseudo_random % x;
883                 D1(printk(KERN_DEBUG "Rotating erasable_list by %d\n", rotateby));
884
885                 rotate_list((&c->erasable_list), rotateby);
886
887                 D1(printk(KERN_DEBUG "Erase block at front of erasable_list is at %08x\n",
888                           list_entry(c->erasable_list.next, struct jffs2_eraseblock, list)->offset));
889         } else {
890                 D1(printk(KERN_DEBUG "Not rotating empty erasable_list\n"));
891         }
892
893         if (c->nr_erasing_blocks) {
894                 rotateby = pseudo_random % c->nr_erasing_blocks;
895                 D1(printk(KERN_DEBUG "Rotating erase_pending_list by %d\n", rotateby));
896
897                 rotate_list((&c->erase_pending_list), rotateby);
898
899                 D1(printk(KERN_DEBUG "Erase block at front of erase_pending_list is at %08x\n",
900                           list_entry(c->erase_pending_list.next, struct jffs2_eraseblock, list)->offset));
901         } else {
902                 D1(printk(KERN_DEBUG "Not rotating empty erase_pending_list\n"));
903         }
904
905         if (c->nr_free_blocks) {
906                 rotateby = pseudo_random % c->nr_free_blocks;
907                 D1(printk(KERN_DEBUG "Rotating free_list by %d\n", rotateby));
908
909                 rotate_list((&c->free_list), rotateby);
910
911                 D1(printk(KERN_DEBUG "Erase block at front of free_list is at %08x\n",
912                           list_entry(c->free_list.next, struct jffs2_eraseblock, list)->offset));
913         } else {
914                 D1(printk(KERN_DEBUG "Not rotating empty free_list\n"));
915         }
916 }