xref: /linux/fs/jffs2/scan.c (revision 4bedea94545165364618d403d03b61d797acba0b)
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 }
917