[JFFS2] Core changes required to support JFFS2-on-Dataflash devices.
[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 1.116 2005/02/09 09:09:02 pavlov 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 #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
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                 ACCT_PARANOIA_CHECK(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 #if defined CONFIG_JFFS2_FS_NAND || defined CONFIG_JFFS2_FS_NOR_ECC
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_NAND
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_NAND
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_NAND
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                 return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
355         }
356         if (ofs) {
357                 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
358                           jeb->offset + ofs));
359                 DIRTY_SPACE(ofs);
360         }
361
362         /* Now ofs is a complete physical flash offset as it always was... */
363         ofs += jeb->offset;
364
365         noise = 10;
366
367 scan_more:      
368         while(ofs < jeb->offset + c->sector_size) {
369
370                 D1(ACCT_PARANOIA_CHECK(jeb));
371
372                 cond_resched();
373
374                 if (ofs & 3) {
375                         printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
376                         ofs = PAD(ofs);
377                         continue;
378                 }
379                 if (ofs == prevofs) {
380                         printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
381                         DIRTY_SPACE(4);
382                         ofs += 4;
383                         continue;
384                 }
385                 prevofs = ofs;
386
387                 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
388                         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),
389                                   jeb->offset, c->sector_size, ofs, sizeof(*node)));
390                         DIRTY_SPACE((jeb->offset + c->sector_size)-ofs);
391                         break;
392                 }
393
394                 if (buf_ofs + buf_len < ofs + sizeof(*node)) {
395                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
396                         D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n",
397                                   sizeof(struct jffs2_unknown_node), buf_len, ofs));
398                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
399                         if (err)
400                                 return err;
401                         buf_ofs = ofs;
402                 }
403
404                 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
405
406                 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
407                         uint32_t inbuf_ofs;
408                         uint32_t empty_start;
409
410                         empty_start = ofs;
411                         ofs += 4;
412
413                         D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
414                 more_empty:
415                         inbuf_ofs = ofs - buf_ofs;
416                         while (inbuf_ofs < buf_len) {
417                                 if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
418                                         printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
419                                                empty_start, ofs);
420                                         DIRTY_SPACE(ofs-empty_start);
421                                         goto scan_more;
422                                 }
423
424                                 inbuf_ofs+=4;
425                                 ofs += 4;
426                         }
427                         /* Ran off end. */
428                         D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));
429
430                         /* If we're only checking the beginning of a block with a cleanmarker,
431                            bail now */
432                         if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) && 
433                             c->cleanmarker_size && !jeb->dirty_size && !jeb->first_node->next_in_ino) {
434                                 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size)));
435                                 return BLK_STATE_CLEANMARKER;
436                         }
437
438                         /* See how much more there is to read in this eraseblock... */
439                         buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
440                         if (!buf_len) {
441                                 /* No more to read. Break out of main loop without marking 
442                                    this range of empty space as dirty (because it's not) */
443                                 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n",
444                                           empty_start));
445                                 break;
446                         }
447                         D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
448                         err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
449                         if (err)
450                                 return err;
451                         buf_ofs = ofs;
452                         goto more_empty;
453                 }
454
455                 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
456                         printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs);
457                         DIRTY_SPACE(4);
458                         ofs += 4;
459                         continue;
460                 }
461                 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
462                         D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
463                         DIRTY_SPACE(4);
464                         ofs += 4;
465                         continue;
466                 }
467                 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
468                         printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
469                         printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n");
470                         DIRTY_SPACE(4);
471                         ofs += 4;
472                         continue;
473                 }
474                 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
475                         /* OK. We're out of possibilities. Whinge and move on */
476                         noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n", 
477                                      JFFS2_MAGIC_BITMASK, ofs, 
478                                      je16_to_cpu(node->magic));
479                         DIRTY_SPACE(4);
480                         ofs += 4;
481                         continue;
482                 }
483                 /* We seem to have a node of sorts. Check the CRC */
484                 crcnode.magic = node->magic;
485                 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
486                 crcnode.totlen = node->totlen;
487                 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
488
489                 if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
490                         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",
491                                      ofs, je16_to_cpu(node->magic),
492                                      je16_to_cpu(node->nodetype), 
493                                      je32_to_cpu(node->totlen),
494                                      je32_to_cpu(node->hdr_crc),
495                                      hdr_crc);
496                         DIRTY_SPACE(4);
497                         ofs += 4;
498                         continue;
499                 }
500
501                 if (ofs + je32_to_cpu(node->totlen) > 
502                     jeb->offset + c->sector_size) {
503                         /* Eep. Node goes over the end of the erase block. */
504                         printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n",
505                                ofs, je32_to_cpu(node->totlen));
506                         printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n");
507                         DIRTY_SPACE(4);
508                         ofs += 4;
509                         continue;
510                 }
511
512                 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
513                         /* Wheee. This is an obsoleted node */
514                         D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
515                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
516                         ofs += PAD(je32_to_cpu(node->totlen));
517                         continue;
518                 }
519
520                 switch(je16_to_cpu(node->nodetype)) {
521                 case JFFS2_NODETYPE_INODE:
522                         if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
523                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
524                                 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n",
525                                           sizeof(struct jffs2_raw_inode), buf_len, ofs));
526                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
527                                 if (err)
528                                         return err;
529                                 buf_ofs = ofs;
530                                 node = (void *)buf;
531                         }
532                         err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs);
533                         if (err) return err;
534                         ofs += PAD(je32_to_cpu(node->totlen));
535                         break;
536                         
537                 case JFFS2_NODETYPE_DIRENT:
538                         if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
539                                 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
540                                 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n",
541                                           je32_to_cpu(node->totlen), buf_len, ofs));
542                                 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
543                                 if (err)
544                                         return err;
545                                 buf_ofs = ofs;
546                                 node = (void *)buf;
547                         }
548                         err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs);
549                         if (err) return err;
550                         ofs += PAD(je32_to_cpu(node->totlen));
551                         break;
552
553                 case JFFS2_NODETYPE_CLEANMARKER:
554                         D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
555                         if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
556                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n", 
557                                        ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
558                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
559                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
560                         } else if (jeb->first_node) {
561                                 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset);
562                                 DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
563                                 ofs += PAD(sizeof(struct jffs2_unknown_node));
564                         } else {
565                                 struct jffs2_raw_node_ref *marker_ref = jffs2_alloc_raw_node_ref();
566                                 if (!marker_ref) {
567                                         printk(KERN_NOTICE "Failed to allocate node ref for clean marker\n");
568                                         return -ENOMEM;
569                                 }
570                                 marker_ref->next_in_ino = NULL;
571                                 marker_ref->next_phys = NULL;
572                                 marker_ref->flash_offset = ofs | REF_NORMAL;
573                                 marker_ref->__totlen = c->cleanmarker_size;
574                                 jeb->first_node = jeb->last_node = marker_ref;
575                              
576                                 USED_SPACE(PAD(c->cleanmarker_size));
577                                 ofs += PAD(c->cleanmarker_size);
578                         }
579                         break;
580
581                 case JFFS2_NODETYPE_PADDING:
582                         DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
583                         ofs += PAD(je32_to_cpu(node->totlen));
584                         break;
585
586                 default:
587                         switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
588                         case JFFS2_FEATURE_ROCOMPAT:
589                                 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
590                                 c->flags |= JFFS2_SB_FLAG_RO;
591                                 if (!(jffs2_is_readonly(c)))
592                                         return -EROFS;
593                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
594                                 ofs += PAD(je32_to_cpu(node->totlen));
595                                 break;
596
597                         case JFFS2_FEATURE_INCOMPAT:
598                                 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs);
599                                 return -EINVAL;
600
601                         case JFFS2_FEATURE_RWCOMPAT_DELETE:
602                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
603                                 DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
604                                 ofs += PAD(je32_to_cpu(node->totlen));
605                                 break;
606
607                         case JFFS2_FEATURE_RWCOMPAT_COPY:
608                                 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs));
609                                 USED_SPACE(PAD(je32_to_cpu(node->totlen)));
610                                 ofs += PAD(je32_to_cpu(node->totlen));
611                                 break;
612                         }
613                 }
614         }
615
616
617         D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x\n", jeb->offset, 
618                   jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size));
619
620         /* mark_node_obsolete can add to wasted !! */
621         if (jeb->wasted_size) {
622                 jeb->dirty_size += jeb->wasted_size;
623                 c->dirty_size += jeb->wasted_size;
624                 c->wasted_size -= jeb->wasted_size;
625                 jeb->wasted_size = 0;
626         }
627
628         if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size 
629                 && (!jeb->first_node || !jeb->first_node->next_in_ino) )
630                 return BLK_STATE_CLEANMARKER;
631                 
632         /* move blocks with max 4 byte dirty space to cleanlist */      
633         else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
634                 c->dirty_size -= jeb->dirty_size;
635                 c->wasted_size += jeb->dirty_size; 
636                 jeb->wasted_size += jeb->dirty_size;
637                 jeb->dirty_size = 0;
638                 return BLK_STATE_CLEAN;
639         } else if (jeb->used_size || jeb->unchecked_size)
640                 return BLK_STATE_PARTDIRTY;
641         else
642                 return BLK_STATE_ALLDIRTY;
643 }
644
645 static struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
646 {
647         struct jffs2_inode_cache *ic;
648
649         ic = jffs2_get_ino_cache(c, ino);
650         if (ic)
651                 return ic;
652
653         if (ino > c->highest_ino)
654                 c->highest_ino = ino;
655
656         ic = jffs2_alloc_inode_cache();
657         if (!ic) {
658                 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n");
659                 return NULL;
660         }
661         memset(ic, 0, sizeof(*ic));
662
663         ic->ino = ino;
664         ic->nodes = (void *)ic;
665         jffs2_add_ino_cache(c, ic);
666         if (ino == 1)
667                 ic->nlink = 1;
668         return ic;
669 }
670
671 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 
672                                  struct jffs2_raw_inode *ri, uint32_t ofs)
673 {
674         struct jffs2_raw_node_ref *raw;
675         struct jffs2_inode_cache *ic;
676         uint32_t ino = je32_to_cpu(ri->ino);
677
678         D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));
679
680         /* We do very little here now. Just check the ino# to which we should attribute
681            this node; we can do all the CRC checking etc. later. There's a tradeoff here -- 
682            we used to scan the flash once only, reading everything we want from it into
683            memory, then building all our in-core data structures and freeing the extra
684            information. Now we allow the first part of the mount to complete a lot quicker,
685            but we have to go _back_ to the flash in order to finish the CRC checking, etc. 
686            Which means that the _full_ amount of time to get to proper write mode with GC
687            operational may actually be _longer_ than before. Sucks to be me. */
688
689         raw = jffs2_alloc_raw_node_ref();
690         if (!raw) {
691                 printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node reference failed\n");
692                 return -ENOMEM;
693         }
694
695         ic = jffs2_get_ino_cache(c, ino);
696         if (!ic) {
697                 /* Inocache get failed. Either we read a bogus ino# or it's just genuinely the
698                    first node we found for this inode. Do a CRC check to protect against the former
699                    case */
700                 uint32_t crc = crc32(0, ri, sizeof(*ri)-8);
701
702                 if (crc != je32_to_cpu(ri->node_crc)) {
703                         printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
704                                ofs, je32_to_cpu(ri->node_crc), crc);
705                         /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
706                         DIRTY_SPACE(PAD(je32_to_cpu(ri->totlen)));
707                         jffs2_free_raw_node_ref(raw);
708                         return 0;
709                 }
710                 ic = jffs2_scan_make_ino_cache(c, ino);
711                 if (!ic) {
712                         jffs2_free_raw_node_ref(raw);
713                         return -ENOMEM;
714                 }
715         }
716
717         /* Wheee. It worked */
718
719         raw->flash_offset = ofs | REF_UNCHECKED;
720         raw->__totlen = PAD(je32_to_cpu(ri->totlen));
721         raw->next_phys = NULL;
722         raw->next_in_ino = ic->nodes;
723
724         ic->nodes = raw;
725         if (!jeb->first_node)
726                 jeb->first_node = raw;
727         if (jeb->last_node)
728                 jeb->last_node->next_phys = raw;
729         jeb->last_node = raw;
730
731         D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n", 
732                   je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
733                   je32_to_cpu(ri->offset),
734                   je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));
735
736         pseudo_random += je32_to_cpu(ri->version);
737
738         UNCHECKED_SPACE(PAD(je32_to_cpu(ri->totlen)));
739         return 0;
740 }
741
742 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 
743                                   struct jffs2_raw_dirent *rd, uint32_t ofs)
744 {
745         struct jffs2_raw_node_ref *raw;
746         struct jffs2_full_dirent *fd;
747         struct jffs2_inode_cache *ic;
748         uint32_t crc;
749
750         D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));
751
752         /* We don't get here unless the node is still valid, so we don't have to
753            mask in the ACCURATE bit any more. */
754         crc = crc32(0, rd, sizeof(*rd)-8);
755
756         if (crc != je32_to_cpu(rd->node_crc)) {
757                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
758                        ofs, je32_to_cpu(rd->node_crc), crc);
759                 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */
760                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
761                 return 0;
762         }
763
764         pseudo_random += je32_to_cpu(rd->version);
765
766         fd = jffs2_alloc_full_dirent(rd->nsize+1);
767         if (!fd) {
768                 return -ENOMEM;
769         }
770         memcpy(&fd->name, rd->name, rd->nsize);
771         fd->name[rd->nsize] = 0;
772
773         crc = crc32(0, fd->name, rd->nsize);
774         if (crc != je32_to_cpu(rd->name_crc)) {
775                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
776                        ofs, je32_to_cpu(rd->name_crc), crc);    
777                 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino)));
778                 jffs2_free_full_dirent(fd);
779                 /* FIXME: Why do we believe totlen? */
780                 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */
781                 DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
782                 return 0;
783         }
784         raw = jffs2_alloc_raw_node_ref();
785         if (!raw) {
786                 jffs2_free_full_dirent(fd);
787                 printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node reference failed\n");
788                 return -ENOMEM;
789         }
790         ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
791         if (!ic) {
792                 jffs2_free_full_dirent(fd);
793                 jffs2_free_raw_node_ref(raw);
794                 return -ENOMEM;
795         }
796         
797         raw->__totlen = PAD(je32_to_cpu(rd->totlen));
798         raw->flash_offset = ofs | REF_PRISTINE;
799         raw->next_phys = NULL;
800         raw->next_in_ino = ic->nodes;
801         ic->nodes = raw;
802         if (!jeb->first_node)
803                 jeb->first_node = raw;
804         if (jeb->last_node)
805                 jeb->last_node->next_phys = raw;
806         jeb->last_node = raw;
807
808         fd->raw = raw;
809         fd->next = NULL;
810         fd->version = je32_to_cpu(rd->version);
811         fd->ino = je32_to_cpu(rd->ino);
812         fd->nhash = full_name_hash(fd->name, rd->nsize);
813         fd->type = rd->type;
814         USED_SPACE(PAD(je32_to_cpu(rd->totlen)));
815         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
816
817         return 0;
818 }
819
820 static int count_list(struct list_head *l)
821 {
822         uint32_t count = 0;
823         struct list_head *tmp;
824
825         list_for_each(tmp, l) {
826                 count++;
827         }
828         return count;
829 }
830
831 /* Note: This breaks if list_empty(head). I don't care. You
832    might, if you copy this code and use it elsewhere :) */
833 static void rotate_list(struct list_head *head, uint32_t count)
834 {
835         struct list_head *n = head->next;
836
837         list_del(head);
838         while(count--) {
839                 n = n->next;
840         }
841         list_add(head, n);
842 }
843
844 void jffs2_rotate_lists(struct jffs2_sb_info *c)
845 {
846         uint32_t x;
847         uint32_t rotateby;
848
849         x = count_list(&c->clean_list);
850         if (x) {
851                 rotateby = pseudo_random % x;
852                 D1(printk(KERN_DEBUG "Rotating clean_list by %d\n", rotateby));
853
854                 rotate_list((&c->clean_list), rotateby);
855
856                 D1(printk(KERN_DEBUG "Erase block at front of clean_list is at %08x\n",
857                           list_entry(c->clean_list.next, struct jffs2_eraseblock, list)->offset));
858         } else {
859                 D1(printk(KERN_DEBUG "Not rotating empty clean_list\n"));
860         }
861
862         x = count_list(&c->very_dirty_list);
863         if (x) {
864                 rotateby = pseudo_random % x;
865                 D1(printk(KERN_DEBUG "Rotating very_dirty_list by %d\n", rotateby));
866
867                 rotate_list((&c->very_dirty_list), rotateby);
868
869                 D1(printk(KERN_DEBUG "Erase block at front of very_dirty_list is at %08x\n",
870                           list_entry(c->very_dirty_list.next, struct jffs2_eraseblock, list)->offset));
871         } else {
872                 D1(printk(KERN_DEBUG "Not rotating empty very_dirty_list\n"));
873         }
874
875         x = count_list(&c->dirty_list);
876         if (x) {
877                 rotateby = pseudo_random % x;
878                 D1(printk(KERN_DEBUG "Rotating dirty_list by %d\n", rotateby));
879
880                 rotate_list((&c->dirty_list), rotateby);
881
882                 D1(printk(KERN_DEBUG "Erase block at front of dirty_list is at %08x\n",
883                           list_entry(c->dirty_list.next, struct jffs2_eraseblock, list)->offset));
884         } else {
885                 D1(printk(KERN_DEBUG "Not rotating empty dirty_list\n"));
886         }
887
888         x = count_list(&c->erasable_list);
889         if (x) {
890                 rotateby = pseudo_random % x;
891                 D1(printk(KERN_DEBUG "Rotating erasable_list by %d\n", rotateby));
892
893                 rotate_list((&c->erasable_list), rotateby);
894
895                 D1(printk(KERN_DEBUG "Erase block at front of erasable_list is at %08x\n",
896                           list_entry(c->erasable_list.next, struct jffs2_eraseblock, list)->offset));
897         } else {
898                 D1(printk(KERN_DEBUG "Not rotating empty erasable_list\n"));
899         }
900
901         if (c->nr_erasing_blocks) {
902                 rotateby = pseudo_random % c->nr_erasing_blocks;
903                 D1(printk(KERN_DEBUG "Rotating erase_pending_list by %d\n", rotateby));
904
905                 rotate_list((&c->erase_pending_list), rotateby);
906
907                 D1(printk(KERN_DEBUG "Erase block at front of erase_pending_list is at %08x\n",
908                           list_entry(c->erase_pending_list.next, struct jffs2_eraseblock, list)->offset));
909         } else {
910                 D1(printk(KERN_DEBUG "Not rotating empty erase_pending_list\n"));
911         }
912
913         if (c->nr_free_blocks) {
914                 rotateby = pseudo_random % c->nr_free_blocks;
915                 D1(printk(KERN_DEBUG "Rotating free_list by %d\n", rotateby));
916
917                 rotate_list((&c->free_list), rotateby);
918
919                 D1(printk(KERN_DEBUG "Erase block at front of free_list is at %08x\n",
920                           list_entry(c->free_list.next, struct jffs2_eraseblock, list)->offset));
921         } else {
922                 D1(printk(KERN_DEBUG "Not rotating empty free_list\n"));
923         }
924 }