scan.c

开放源码实时操作系统源码.

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright (C) 2001-2003 Red Hat, Inc.
 *
 * Created by David Woodhouse <[e-mail]>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 * $Id: scan.c,v 1.121 2005/07/20 15:32:28 dedekind Exp $
 *
 */
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/pagemap.h>
#include <linux/crc32.h>
#include <linux/compiler.h>
#include "nodelist.h"

#define DEFAULT_EMPTY_SCAN_SIZE 1024

#define DIRTY_SPACE(x) do { typeof(x) _x = (x); \
		c->free_size -= _x; c->dirty_size += _x; \
		jeb->free_size -= _x ; jeb->dirty_size += _x; \
		}while(0)
#define USED_SPACE(x) do { typeof(x) _x = (x); \
		c->free_size -= _x; c->used_size += _x; \
		jeb->free_size -= _x ; jeb->used_size += _x; \
		}while(0)
#define UNCHECKED_SPACE(x) do { typeof(x) _x = (x); \
		c->free_size -= _x; c->unchecked_size += _x; \
		jeb->free_size -= _x ; jeb->unchecked_size += _x; \
		}while(0)

#define noisy_printk(noise, args...) do { \
	if (*(noise)) { \
		printk(KERN_NOTICE args); \
		 (*(noise))--; \
		 if (!(*(noise))) { \
			 printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \
		 } \
	} \
} while(0)

static uint32_t pseudo_random;

static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				  unsigned char *buf, uint32_t buf_size);

/* These helper functions _must_ increase ofs and also do the dirty/used space accounting. 
 * Returning an error will abort the mount - bad checksums etc. should just mark the space
 * as dirty.
 */
static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 
				 struct jffs2_raw_inode *ri, uint32_t ofs);
static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				 struct jffs2_raw_dirent *rd, uint32_t ofs);

#define BLK_STATE_ALLFF		0
#define BLK_STATE_CLEAN		1
#define BLK_STATE_PARTDIRTY	2
#define BLK_STATE_CLEANMARKER	3
#define BLK_STATE_ALLDIRTY	4
#define BLK_STATE_BADBLOCK	5

static inline int min_free(struct jffs2_sb_info *c)
{
	uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
	if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
		return c->wbuf_pagesize;
#endif
	return min;

}

static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
	if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
		return sector_size;
	else
		return DEFAULT_EMPTY_SCAN_SIZE;
}

int jffs2_scan_medium(struct jffs2_sb_info *c)
{
	int i, ret;
	uint32_t empty_blocks = 0, bad_blocks = 0;
	unsigned char *flashbuf = NULL;
	uint32_t buf_size = 0;
#ifndef __ECOS
	size_t pointlen;

	if (c->mtd->point) {
		ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
		if (!ret && pointlen < c->mtd->size) {
			/* Don't muck about if it won't let us point to the whole flash */
			D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen));
			c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
			flashbuf = NULL;
		}
		if (ret)
			D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
	}
#endif
	if (!flashbuf) {
		/* For NAND it's quicker to read a whole eraseblock at a time,
		   apparently */
		if (jffs2_cleanmarker_oob(c))
			buf_size = c->sector_size;
		else
			buf_size = PAGE_SIZE;

		/* Respect kmalloc limitations */
		if (buf_size > 128*1024)
			buf_size = 128*1024;

		D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
		flashbuf = kmalloc(buf_size, GFP_KERNEL);
		if (!flashbuf)
			return -ENOMEM;
	}

	for (i=0; i<c->nr_blocks; i++) {
		struct jffs2_eraseblock *jeb = &c->blocks[i];

		ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset), buf_size);

		if (ret < 0)
			goto out;

		jffs2_dbg_acct_paranoia_check_nolock(c, jeb);

		/* Now decide which list to put it on */
		switch(ret) {
		case BLK_STATE_ALLFF:
			/* 
			 * Empty block.   Since we can't be sure it 
			 * was entirely erased, we just queue it for erase
			 * again.  It will be marked as such when the erase
			 * is complete.  Meanwhile we still count it as empty
			 * for later checks.
			 */
			empty_blocks++;
			list_add(&jeb->list, &c->erase_pending_list);
			c->nr_erasing_blocks++;
			break;

		case BLK_STATE_CLEANMARKER:
			/* Only a CLEANMARKER node is valid */
			if (!jeb->dirty_size) {
				/* It's actually free */
				list_add(&jeb->list, &c->free_list);
				c->nr_free_blocks++;
			} else {
				/* Dirt */
				D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset));
				list_add(&jeb->list, &c->erase_pending_list);
				c->nr_erasing_blocks++;
			}
			break;

		case BLK_STATE_CLEAN:
                        /* Full (or almost full) of clean data. Clean list */
                        list_add(&jeb->list, &c->clean_list);
			break;

		case BLK_STATE_PARTDIRTY:
                        /* Some data, but not full. Dirty list. */
                        /* We want to remember the block with most free space
                           and stick it in the 'nextblock' position to start writing to it. */
                        if (jeb->free_size > min_free(c) && 
			    (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
                                /* Better candidate for the next writes to go to */
                                if (c->nextblock) {
					c->nextblock->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
					c->dirty_size += c->nextblock->free_size + c->nextblock->wasted_size;
					c->free_size -= c->nextblock->free_size;
					c->wasted_size -= c->nextblock->wasted_size;
					c->nextblock->free_size = c->nextblock->wasted_size = 0;
					if (VERYDIRTY(c, c->nextblock->dirty_size)) {
						list_add(&c->nextblock->list, &c->very_dirty_list);
					} else {
						list_add(&c->nextblock->list, &c->dirty_list);
					}
				}
                                c->nextblock = jeb;
                        } else {
				jeb->dirty_size += jeb->free_size + jeb->wasted_size;
				c->dirty_size += jeb->free_size + jeb->wasted_size;
				c->free_size -= jeb->free_size;
				c->wasted_size -= jeb->wasted_size;
				jeb->free_size = jeb->wasted_size = 0;
				if (VERYDIRTY(c, jeb->dirty_size)) {
					list_add(&jeb->list, &c->very_dirty_list);
				} else {
					list_add(&jeb->list, &c->dirty_list);
				}
                        }
			break;

		case BLK_STATE_ALLDIRTY:
			/* Nothing valid - not even a clean marker. Needs erasing. */
                        /* For now we just put it on the erasing list. We'll start the erases later */
			D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset));
                        list_add(&jeb->list, &c->erase_pending_list);
			c->nr_erasing_blocks++;
			break;
			
		case BLK_STATE_BADBLOCK:
			D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset));
                        list_add(&jeb->list, &c->bad_list);
			c->bad_size += c->sector_size;
			c->free_size -= c->sector_size;
			bad_blocks++;
			break;
		default:
			printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
			BUG();	
		}
	}
	
	/* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
	if (c->nextblock && (c->nextblock->dirty_size)) {
		c->nextblock->wasted_size += c->nextblock->dirty_size;
		c->wasted_size += c->nextblock->dirty_size;
		c->dirty_size -= c->nextblock->dirty_size;
		c->nextblock->dirty_size = 0;
	}
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
	if (!jffs2_can_mark_obsolete(c) && c->nextblock && (c->nextblock->free_size & (c->wbuf_pagesize-1))) {
		/* If we're going to start writing into a block which already 
		   contains data, and the end of the data isn't page-aligned,
		   skip a little and align it. */

		uint32_t skip = c->nextblock->free_size & (c->wbuf_pagesize-1);

		D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n",
			  skip));
		c->nextblock->wasted_size += skip;
		c->wasted_size += skip;

		c->nextblock->free_size -= skip;
		c->free_size -= skip;
	}
#endif
	if (c->nr_erasing_blocks) {
		if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) { 
			printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
			printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks);
			ret = -EIO;
			goto out;
		}
		jffs2_erase_pending_trigger(c);
	}
	ret = 0;
 out:
	if (buf_size)
		kfree(flashbuf);
#ifndef __ECOS
	else 
		c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
#endif
	return ret;
}

static int jffs2_fill_scan_buf (struct jffs2_sb_info *c, unsigned char *buf,
				uint32_t ofs, uint32_t len)
{
	int ret;
	size_t retlen;

	ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
	if (ret) {
		D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret));
		return ret;
	}
	if (retlen < len) {
		D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen));
		return -EIO;
	}
	D2(printk(KERN_DEBUG "Read 0x%x bytes from 0x%08x into buf\n", len, ofs));
	D2(printk(KERN_DEBUG "000: %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
		  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]));
	return 0;
}

static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				  unsigned char *buf, uint32_t buf_size) {
	struct jffs2_unknown_node *node;
	struct jffs2_unknown_node crcnode;
	uint32_t ofs, prevofs;
	uint32_t hdr_crc, buf_ofs, buf_len;
	int err;
	int noise = 0;
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
	int cleanmarkerfound = 0;
#endif

	ofs = jeb->offset;
	prevofs = jeb->offset - 1;

	D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));

#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
	if (jffs2_cleanmarker_oob(c)) {
		int ret = jffs2_check_nand_cleanmarker(c, jeb);
		D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
		/* Even if it's not found, we still scan to see