wbuf.c

jffs2源代码基于2。6内核

	/* Now splitvec points to the start of the bits we have to copy
	   into the wbuf */
	wbuf_ptr = c->wbuf;

	for ( ; splitvec < outvec; splitvec++) {
		/* Don't copy the wbuf into itself */
		if (outvecs[splitvec].iov_base == c->wbuf)
			continue;
		memcpy(wbuf_ptr, outvecs[splitvec].iov_base, outvecs[splitvec].iov_len);
		wbuf_ptr += outvecs[splitvec].iov_len;
		donelen += outvecs[splitvec].iov_len;
	}
	c->wbuf_len = wbuf_ptr - c->wbuf;

	/* If there's a remainder in the wbuf and it's a non-GC write,
	   remember that the wbuf affects this ino */
alldone:
	*retlen = donelen;

	if (c->wbuf_len && ino)
		jffs2_wbuf_dirties_inode(c, ino);

	return 0;
}

/*
 *	This is the entry for flash write.
 *	Check, if we work on NAND FLASH, if so build an kvec and write it via vritev
*/
int jffs2_flash_write(struct jffs2_sb_info *c, loff_t ofs, size_t len, size_t *retlen, const u_char *buf)
{
	struct kvec vecs[1];

	if (jffs2_can_mark_obsolete(c))
		return c->mtd->write(c->mtd, ofs, len, retlen, buf);

	vecs[0].iov_base = (unsigned char *) buf;
	vecs[0].iov_len = len;
	return jffs2_flash_writev(c, vecs, 1, ofs, retlen, 0);
}

/*
	Handle readback from writebuffer and ECC failure return
*/
int jffs2_flash_read(struct jffs2_sb_info *c, loff_t ofs, size_t len, size_t *retlen, u_char *buf)
{
	loff_t	orbf = 0, owbf = 0, lwbf = 0;
	int	ret;

	/* Read flash */
	if (!jffs2_can_mark_obsolete(c)) {
		ret = c->mtd->read_ecc(c->mtd, ofs, len, retlen, buf, NULL, c->oobinfo);

		if ( (ret == -EBADMSG) && (*retlen == len) ) {
			printk(KERN_WARNING "mtd->read(0x%zx bytes from 0x%llx) returned ECC error\n",
			       len, ofs);
			/* 
			 * We have the raw data without ECC correction in the buffer, maybe 
			 * we are lucky and all data or parts are correct. We check the node.
			 * If data are corrupted node check will sort it out.
			 * We keep this block, it will fail on write or erase and the we
			 * mark it bad. Or should we do that now? But we should give him a chance.
			 * Maybe we had a system crash or power loss before the ecc write or  
			 * a erase was completed.
			 * So we return success. :)
			 */
		 	ret = 0;
		 }	
	} else
		return c->mtd->read(c->mtd, ofs, len, retlen, buf);

	/* if no writebuffer available or write buffer empty, return */
	if (!c->wbuf_pagesize || !c->wbuf_len)
		return ret;

	/* if we read in a different block, return */
	if ( (ofs & ~(c->sector_size-1)) != (c->wbuf_ofs & ~(c->sector_size-1)) ) 
		return ret;	

	if (ofs >= c->wbuf_ofs) {
		owbf = (ofs - c->wbuf_ofs);	/* offset in write buffer */
		if (owbf > c->wbuf_len)		/* is read beyond write buffer ? */
			return ret;
		lwbf = c->wbuf_len - owbf;	/* number of bytes to copy */
		if (lwbf > len)	
			lwbf = len;
	} else {	
		orbf = (c->wbuf_ofs - ofs);	/* offset in read buffer */
		if (orbf > len)			/* is write beyond write buffer ? */
			return ret;
		lwbf = len - orbf; 		/* number of bytes to copy */
		if (lwbf > c->wbuf_len)	
			lwbf = c->wbuf_len;
	}	
	if (lwbf > 0)
		memcpy(buf+orbf,c->wbuf+owbf,lwbf);

	return ret;
}

/*
 *	Check, if the out of band area is empty
 */
int jffs2_check_oob_empty( struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, int mode)
{
	unsigned char *buf;
	int 	ret = 0;
	int	i,len,page;
	size_t  retlen;
	int	oob_size;

	/* allocate a buffer for all oob data in this sector */
	oob_size = c->mtd->oobsize;
	len = 4 * oob_size;
	buf = kmalloc(len, GFP_KERNEL);
	if (!buf) {
		printk(KERN_NOTICE "jffs2_check_oob_empty(): allocation of temporary data buffer for oob check failed\n");
		return -ENOMEM;
	}
	/* 
	 * if mode = 0, we scan for a total empty oob area, else we have
	 * to take care of the cleanmarker in the first page of the block
	*/
	ret = jffs2_flash_read_oob(c, jeb->offset, len , &retlen, buf);
	if (ret) {
		D1(printk(KERN_WARNING "jffs2_check_oob_empty(): Read OOB failed %d for block at %08x\n", ret, jeb->offset));
		goto out;
	}
	
	if (retlen < len) {
		D1(printk(KERN_WARNING "jffs2_check_oob_empty(): Read OOB return short read "
			  "(%zd bytes not %d) for block at %08x\n", retlen, len, jeb->offset));
		ret = -EIO;
		goto out;
	}
	
	/* Special check for first page */
	for(i = 0; i < oob_size ; i++) {
		/* Yeah, we know about the cleanmarker. */
		if (mode && i >= c->fsdata_pos && 
		    i < c->fsdata_pos + c->fsdata_len)
			continue;

		if (buf[i] != 0xFF) {
			D2(printk(KERN_DEBUG "Found %02x at %x in OOB for %08x\n",
				  buf[page+i], page+i, jeb->offset));
			ret = 1; 
			goto out;
		}
	}

	/* we know, we are aligned :) */	
	for (page = oob_size; page < len; page += sizeof(long)) {
		unsigned long dat = *(unsigned long *)(&buf[page]);
		if(dat != -1) {
			ret = 1; 
			goto out;
		}
	}

out:
	kfree(buf);	
	
	return ret;
}

/*
*	Scan for a valid cleanmarker and for bad blocks
*	For virtual blocks (concatenated physical blocks) check the cleanmarker
*	only in the first page of the first physical block, but scan for bad blocks in all
*	physical blocks
*/
int jffs2_check_nand_cleanmarker (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
{
	struct jffs2_unknown_node n;
	unsigned char buf[2 * NAND_MAX_OOBSIZE];
	unsigned char *p;
	int ret, i, cnt, retval = 0;
	size_t retlen, offset;
	int oob_size;

	offset = jeb->offset;
	oob_size = c->mtd->oobsize;

	/* Loop through the physical blocks */
	for (cnt = 0; cnt < (c->sector_size / c->mtd->erasesize); cnt++) {
		/* Check first if the block is bad. */
		if (c->mtd->block_isbad (c->mtd, offset)) {
			D1 (printk (KERN_WARNING "jffs2_check_nand_cleanmarker(): Bad block at %08x\n", jeb->offset));
			return 2;
		}
		/*
		   *    We read oob data from page 0 and 1 of the block.
		   *    page 0 contains cleanmarker and badblock info
		   *    page 1 contains failure count of this block
		 */
		ret = c->mtd->read_oob (c->mtd, offset, oob_size << 1, &retlen, buf);

		if (ret) {
			D1 (printk (KERN_WARNING "jffs2_check_nand_cleanmarker(): Read OOB failed %d for block at %08x\n", ret, jeb->offset));
			return ret;
		}
		if (retlen < (oob_size << 1)) {
			D1 (printk (KERN_WARNING "jffs2_check_nand_cleanmarker(): Read OOB return short read (%zd bytes not %d) for block at %08x\n", retlen, oob_size << 1, jeb->offset));
			return -EIO;
		}

		/* Check cleanmarker only on the first physical block */
		if (!cnt) {
			n.magic = cpu_to_je16 (JFFS2_MAGIC_BITMASK);
			n.nodetype = cpu_to_je16 (JFFS2_NODETYPE_CLEANMARKER);
			n.totlen = cpu_to_je32 (8);
			p = (unsigned char *) &n;

			for (i = 0; i < c->fsdata_len; i++) {
				if (buf[c->fsdata_pos + i] != p[i]) {
					retval = 1;
				}
			}
			D1(if (retval == 1) {
				printk(KERN_WARNING "jffs2_check_nand_cleanmarker(): Cleanmarker node not detected in block at %08x\n", jeb->offset);
				printk(KERN_WARNING "OOB at %08x was ", offset);
				for (i=0; i < oob_size; i++) {
					printk("%02x ", buf[i]);
				}
				printk("\n");
			})
		}
		offset += c->mtd->erasesize;
	}
	return retval;
}

int jffs2_write_nand_cleanmarker(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
{
	struct 	jffs2_unknown_node n;
	int 	ret;
	size_t 	retlen;

	n.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
	n.nodetype = cpu_to_je16(JFFS2_NODETYPE_CLEANMARKER);
	n.totlen = cpu_to_je32(8);

	ret = jffs2_flash_write_oob(c, jeb->offset + c->fsdata_pos, c->fsdata_len, &retlen, (unsigned char *)&n);
	
	if (ret) {
		D1(printk(KERN_WARNING "jffs2_write_nand_cleanmarker(): Write failed for block at %08x: error %d\n", jeb->offset, ret));
		return ret;
	}
	if (retlen != c->fsdata_len) {
		D1(printk(KERN_WARNING "jffs2_write_nand_cleanmarker(): Short write for block at %08x: %zd not %d\n", jeb->offset, retlen, c->fsdata_len));
		return ret;
	}
	return 0;
}

/* 
 * On NAND we try to mark this block bad. If the block was erased more
 * than MAX_ERASE_FAILURES we mark it finaly bad.
 * Don't care about failures. This block remains on the erase-pending
 * or badblock list as long as nobody manipulates the flash with
 * a bootloader or something like that.
 */

int jffs2_write_nand_badblock(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t bad_offset)
{
	int 	ret;

	/* if the count is < max, we try to write the counter to the 2nd page oob area */
	if( ++jeb->bad_count < MAX_ERASE_FAILURES)
		return 0;

	if (!c->mtd->block_markbad)
		return 1; // What else can we do?

	D1(printk(KERN_WARNING "jffs2_write_nand_badblock(): Marking bad block at %08x\n", bad_offset));
	ret = c->mtd->block_markbad(c->mtd, bad_offset);
	
	if (ret) {
		D1(printk(KERN_WARNING "jffs2_write_nand_badblock(): Write failed for block at %08x: error %d\n", jeb->offset, ret));
		return ret;
	}
	return 1;
}

#define NAND_JFFS2_OOB16_FSDALEN	8

static struct nand_oobinfo jffs2_oobinfo_docecc = {
	.useecc = MTD_NANDECC_PLACE,
	.eccbytes = 6,
	.eccpos = {0,1,2,3,4,5}
};


int jffs2_nand_set_oobinfo(struct jffs2_sb_info *c)
{
	struct nand_oobinfo *oinfo = &c->mtd->oobinfo;

	/* Do this only, if we have an oob buffer */
	if (!c->mtd->oobsize)
		return 0;
	
	/* Cleanmarker is out-of-band, so inline size zero */
	c->cleanmarker_size = 0;

	/* Should we use autoplacement ? */
	if (oinfo && oinfo->useecc == MTD_NANDECC_AUTOPLACE) {
		D1(printk(KERN_DEBUG "JFFS2 using autoplace on NAND\n"));
		/* Get the position of the free bytes */
		if (!oinfo->oobfree[0][1]) {
			printk (KERN_WARNING "jffs2_nand_set_oobinfo(): Eeep. Autoplacement selected and no empty space in oob\n");
			return -ENOSPC;
		}
		c->fsdata_pos = oinfo->oobfree[0][0];
		c->fsdata_len = oinfo->oobfree[0][1];
		if (c->fsdata_len > 8)
			c->fsdata_len = 8;
	} else {
		/* This is just a legacy fallback and should go away soon */
		switch(c->mtd->ecctype) {
		case MTD_ECC_RS_DiskOnChip:
			printk(KERN_WARNING "JFFS2 using DiskOnChip hardware ECC without autoplacement. Fix it!\n");
			c->oobinfo = &jffs2_oobinfo_docecc;
			c->fsdata_pos = 6;
			c->fsdata_len = NAND_JFFS2_OOB16_FSDALEN;
			c->badblock_pos = 15;
			break;
	
		default:
			D1(printk(KERN_DEBUG "JFFS2 on NAND. No autoplacment info found\n"));
			return -EINVAL;
		}
	}
	return 0;
}

int jffs2_nand_flash_setup(struct jffs2_sb_info *c)
{
	int res;

	/* Initialise write buffer */
	c->wbuf_pagesize = c->mtd->oobblock;
	c->wbuf_ofs = 0xFFFFFFFF;

	
	c->wbuf = kmalloc(c->wbuf_pagesize, GFP_KERNEL);
	if (!c->wbuf)
		return -ENOMEM;

	res = jffs2_nand_set_oobinfo(c);

#ifdef BREAKME
	if (!brokenbuf)
		brokenbuf = kmalloc(c->wbuf_pagesize, GFP_KERNEL);
	if (!brokenbuf) {
		kfree(c->wbuf);
		return -ENOMEM;
	}
	memset(brokenbuf, 0xdb, c->wbuf_pagesize);
#endif
	return res;
}

void jffs2_nand_flash_cleanup(struct jffs2_sb_info *c)
{
	kfree(c->wbuf);
}