--- linux-2.6.22.14/fs/yaffs/yaffs_checkptrw.c	1970-01-01 03:00:00.000000000 +0300
+++ linux/fs/yaffs/yaffs_checkptrw.c	2008-01-15 10:58:25.000000000 +0200
@@ -0,0 +1,366 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+const char *yaffs_checkptrw_c_version =
+    "$Id: yaffs_checkptrw.c,v 1.4 2006/05/23 19:08:41 charles Exp $";
+
+
+#include "yaffs_checkptrw.h"
+
+
+static int yaffs_CheckpointSpaceOk(yaffs_Device *dev)
+{
+
+	int blocksAvailable = dev->nErasedBlocks - dev->nReservedBlocks;
+	
+	T(YAFFS_TRACE_CHECKPOINT,
+		(TSTR("checkpt blocks available = %d" TENDSTR),
+		blocksAvailable));
+		
+	
+	return (blocksAvailable <= 0) ? 0 : 1;
+}
+
+
+
+static int yaffs_CheckpointErase(yaffs_Device *dev)
+{
+	
+	int i;
+	
+
+	if(!dev->eraseBlockInNAND)	
+		return 0;
+	T(YAFFS_TRACE_CHECKPOINT,(TSTR("checking blocks %d to %d"TENDSTR),
+		dev->startBlock,dev->endBlock));
+		
+	for(i = dev->startBlock; i <= dev->endBlock; i++) {
+		yaffs_BlockInfo *bi = &dev->blockInfo[i];
+		if(bi->blockState == YAFFS_BLOCK_STATE_CHECKPOINT){
+			T(YAFFS_TRACE_CHECKPOINT,(TSTR("erasing checkpt block %d"TENDSTR),i));
+			if(dev->eraseBlockInNAND(dev,i)){
+				bi->blockState = YAFFS_BLOCK_STATE_EMPTY;
+				dev->nErasedBlocks++;
+				dev->nFreeChunks += dev->nChunksPerBlock;
+			}
+			else {
+				dev->markNANDBlockBad(dev,i);
+				bi->blockState = YAFFS_BLOCK_STATE_DEAD;
+			}
+		}
+	}
+	
+	dev->blocksInCheckpoint = 0;
+	
+	return 1;
+}
+
+
+static void yaffs_CheckpointFindNextErasedBlock(yaffs_Device *dev)
+{
+	int  i;
+	int blocksAvailable = dev->nErasedBlocks - dev->nReservedBlocks;
+		
+	if(dev->checkpointNextBlock >= 0 &&
+	   dev->checkpointNextBlock <= dev->endBlock &&
+	   blocksAvailable > 0){
+	
+		for(i = dev->checkpointNextBlock; i <= dev->endBlock; i++){
+			yaffs_BlockInfo *bi = &dev->blockInfo[i];
+			if(bi->blockState == YAFFS_BLOCK_STATE_EMPTY){
+				dev->checkpointNextBlock = i + 1;
+				dev->checkpointCurrentBlock = i;
+				T(YAFFS_TRACE_CHECKPOINT,(TSTR("allocating checkpt block %d"TENDSTR),i));
+				return;
+			}
+		}
+	}
+	T(YAFFS_TRACE_CHECKPOINT,(TSTR("out of checkpt blocks"TENDSTR)));
+	
+	dev->checkpointNextBlock = -1;
+	dev->checkpointCurrentBlock = -1;
+}
+
+static void yaffs_CheckpointFindNextCheckpointBlock(yaffs_Device *dev)
+{
+	int  i;
+	yaffs_ExtendedTags tags;
+	
+	if(dev->blocksInCheckpoint < dev->checkpointMaxBlocks) 
+		for(i = dev->checkpointNextBlock; i <= dev->endBlock; i++){
+			int chunk = i * dev->nChunksPerBlock;
+
+			dev->readChunkWithTagsFromNAND(dev,chunk,NULL,&tags);
+						      
+			if(tags.sequenceNumber == YAFFS_SEQUENCE_CHECKPOINT_DATA){
+				/* Right kind of block */
+				dev->checkpointNextBlock = tags.objectId;
+				dev->checkpointCurrentBlock = i;
+				dev->checkpointBlockList[dev->blocksInCheckpoint] = i;
+				dev->blocksInCheckpoint++;
+				T(YAFFS_TRACE_CHECKPOINT,(TSTR("found checkpt block %d"TENDSTR),i));
+				return;
+			}
+		}
+
+	T(YAFFS_TRACE_CHECKPOINT,(TSTR("found no more checkpt blocks"TENDSTR)));
+
+	dev->checkpointNextBlock = -1;
+	dev->checkpointCurrentBlock = -1;
+}
+
+
+int yaffs_CheckpointOpen(yaffs_Device *dev, int forWriting)
+{
+	
+	/* Got the functions we need? */
+	if (!dev->writeChunkWithTagsToNAND ||
+	    !dev->readChunkWithTagsFromNAND ||
+	    !dev->eraseBlockInNAND ||
+	    !dev->markNANDBlockBad)
+		return 0;
+
+	if(forWriting && !yaffs_CheckpointSpaceOk(dev))
+		return 0;
+			
+	if(!dev->checkpointBuffer)
+		dev->checkpointBuffer = YMALLOC_DMA(dev->nBytesPerChunk);
+	if(!dev->checkpointBuffer)
+		return 0;
+
+	
+	dev->checkpointPageSequence = 0;
+	
+	dev->checkpointOpenForWrite = forWriting;
+	
+	dev->checkpointByteCount = 0;
+	dev->checkpointCurrentBlock = -1;
+	dev->checkpointCurrentChunk = -1;
+	dev->checkpointNextBlock = dev->startBlock;
+	
+	/* Erase all the blocks in the checkpoint area */
+	if(forWriting){
+		memset(dev->checkpointBuffer,0,dev->nBytesPerChunk);
+		dev->checkpointByteOffset = 0;
+		return yaffs_CheckpointErase(dev);
+		
+		
+	} else {
+		int i;
+		/* Set to a value that will kick off a read */
+		dev->checkpointByteOffset = dev->nBytesPerChunk;
+		/* A checkpoint block list of 1 checkpoint block per 16 block is (hopefully)
+		 * going to be way more than we need */
+		dev->blocksInCheckpoint = 0;
+		dev->checkpointMaxBlocks = (dev->endBlock - dev->startBlock)/16 + 2;
+		dev->checkpointBlockList = YMALLOC(sizeof(int) * dev->checkpointMaxBlocks);
+		for(i = 0; i < dev->checkpointMaxBlocks; i++)
+			dev->checkpointBlockList[i] = -1;
+	}
+	
+	return 1;
+}
+
+static int yaffs_CheckpointFlushBuffer(yaffs_Device *dev)
+{
+
+	int chunk;
+
+	yaffs_ExtendedTags tags;
+	
+	if(dev->checkpointCurrentBlock < 0){
+		yaffs_CheckpointFindNextErasedBlock(dev);
+		dev->checkpointCurrentChunk = 0;
+	}
+	
+	if(dev->checkpointCurrentBlock < 0)
+		return 0;
+	
+	tags.chunkDeleted = 0;
+	tags.objectId = dev->checkpointNextBlock; /* Hint to next place to look */
+	tags.chunkId = dev->checkpointPageSequence + 1;
+	tags.sequenceNumber =  YAFFS_SEQUENCE_CHECKPOINT_DATA;
+	tags.byteCount = dev->nBytesPerChunk;
+	if(dev->checkpointCurrentChunk == 0){
+		/* First chunk we write for the block? Set block state to
+		   checkpoint */
+		yaffs_BlockInfo *bi = &dev->blockInfo[dev->checkpointCurrentBlock];
+		bi->blockState = YAFFS_BLOCK_STATE_CHECKPOINT;
+		dev->blocksInCheckpoint++;
+	}
+	
+	chunk = dev->checkpointCurrentBlock * dev->nChunksPerBlock + dev->checkpointCurrentChunk;
+		
+	dev->writeChunkWithTagsToNAND(dev,chunk,dev->checkpointBuffer,&tags);
+	dev->checkpointByteOffset = 0;
+	dev->checkpointPageSequence++;	   
+	dev->checkpointCurrentChunk++;
+	if(dev->checkpointCurrentChunk >= dev->nChunksPerBlock){
+		dev->checkpointCurrentChunk = 0;
+		dev->checkpointCurrentBlock = -1;
+	}
+	memset(dev->checkpointBuffer,0,dev->nBytesPerChunk);
+	
+	return 1;
+}
+
+
+int yaffs_CheckpointWrite(yaffs_Device *dev,const void *data, int nBytes)
+{
+	int i=0;
+	int ok = 1;
+
+	
+	__u8 * dataBytes = (__u8 *)data;
+	
+	
+
+	if(!dev->checkpointBuffer)
+		return 0;
+
+	while(i < nBytes && ok) {
+		
+
+		
+		 dev->checkpointBuffer[dev->checkpointByteOffset] = *dataBytes ;
+		dev->checkpointByteOffset++;
+		i++;
+		dataBytes++;
+		dev->checkpointByteCount++;
+		
+		
+		if(dev->checkpointByteOffset < 0 ||
+		   dev->checkpointByteOffset >= dev->nBytesPerChunk) 
+			ok = yaffs_CheckpointFlushBuffer(dev);
+
+	}
+	
+	return 	i;
+}
+
+int yaffs_CheckpointRead(yaffs_Device *dev, void *data, int nBytes)
+{
+	int i=0;
+	int ok = 1;
+	yaffs_ExtendedTags tags;
+
+	
+	int chunk;
+
+	__u8 *dataBytes = (__u8 *)data;
+		
+	if(!dev->checkpointBuffer)
+		return 0;
+
+	while(i < nBytes && ok) {
+	
+	
+		if(dev->checkpointByteOffset < 0 ||
+		   dev->checkpointByteOffset >= dev->nBytesPerChunk) {
+		   
+		   	if(dev->checkpointCurrentBlock < 0){
+				yaffs_CheckpointFindNextCheckpointBlock(dev);
+				dev->checkpointCurrentChunk = 0;
+			}
+			
+			if(dev->checkpointCurrentBlock < 0)
+				ok = 0;
+			else {
+			
+				chunk = dev->checkpointCurrentBlock * dev->nChunksPerBlock + 
+				          dev->checkpointCurrentChunk;
+
+	   			/* read in the next chunk */
+	   			/* printf("read checkpoint page %d\n",dev->checkpointPage); */
+				dev->readChunkWithTagsFromNAND(dev, chunk, 
+							       dev->checkpointBuffer,
+							      &tags);
+						      
+				if(tags.chunkId != (dev->checkpointPageSequence + 1) ||
+				   tags.sequenceNumber != YAFFS_SEQUENCE_CHECKPOINT_DATA)
+				   ok = 0;
+
+				dev->checkpointByteOffset = 0;
+				dev->checkpointPageSequence++;
+				dev->checkpointCurrentChunk++;
+			
+				if(dev->checkpointCurrentChunk >= dev->nChunksPerBlock)
+					dev->checkpointCurrentBlock = -1;
+			}
+		}
+		
+		if(ok){
+			*dataBytes = dev->checkpointBuffer[dev->checkpointByteOffset];
+			dev->checkpointByteOffset++;
+			i++;
+			dataBytes++;
+			dev->checkpointByteCount++;
+		}
+	}
+	
+	return 	i;
+}
+
+int yaffs_CheckpointClose(yaffs_Device *dev)
+{
+
+	if(dev->checkpointOpenForWrite){	
+		if(dev->checkpointByteOffset != 0)
+			yaffs_CheckpointFlushBuffer(dev);
+	} else {
+		int i;
+		for(i = 0; i < dev->blocksInCheckpoint && dev->checkpointBlockList[i] >= 0; i++){
+			yaffs_BlockInfo *bi = &dev->blockInfo[dev->checkpointBlockList[i]];
+			if(bi->blockState == YAFFS_BLOCK_STATE_EMPTY)
+				bi->blockState = YAFFS_BLOCK_STATE_CHECKPOINT;
+			else {
+				// Todo this looks odd...
+			}
+		}
+		YFREE(dev->checkpointBlockList);
+		dev->checkpointBlockList = NULL;
+	}
+
+	dev->nFreeChunks -= dev->blocksInCheckpoint * dev->nChunksPerBlock;
+	dev->nErasedBlocks -= dev->blocksInCheckpoint;
+
+		
+	T(YAFFS_TRACE_CHECKPOINT,(TSTR("checkpoint byte count %d" TENDSTR),
+			dev->checkpointByteCount));
+			
+	if(dev->checkpointBuffer){
+		/* free the buffer */	
+		YFREE(dev->checkpointBuffer);
+		dev->checkpointBuffer = NULL;
+		return 1;
+	}
+	else
+		return 0;
+	
+}
+
+int yaffs_CheckpointInvalidateStream(yaffs_Device *dev)
+{
+	/* Erase the first checksum block */
+
+	T(YAFFS_TRACE_CHECKPOINT,(TSTR("checkpoint invalidate"TENDSTR)));
+
+	if(!yaffs_CheckpointSpaceOk(dev))
+		return 0;
+
+	return yaffs_CheckpointErase(dev);
+}
+
+
+