yaffs_guts.c

yaffs２设备驱动

/*
 * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
 *
 * Copyright (C) 2002-2007 Aleph One Ltd.
 *   for Toby Churchill Ltd and Brightstar Engineering
 *
 * Created by Charles Manning <[e-mail]>
 *
 * 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_guts_c_version =
    "$Id: yaffs_guts.c,v 1.1.1.1 2008/03/28 04:29:21 jlwei Exp $";

#include "yportenv.h"

#include "yaffsinterface.h"
#include "yaffs_guts.h"
#include "yaffs_tagsvalidity.h"

#include "yaffs_tagscompat.h"
#ifndef CONFIG_YAFFS_OWN_SORT
#include "yaffs_qsort.h"
#endif
#include "yaffs_nand.h"

#include "yaffs_checkptrw.h"

#include "yaffs_nand.h"
#include "yaffs_packedtags2.h"


#ifdef CONFIG_YAFFS_WINCE
void yfsd_LockYAFFS(BOOL fsLockOnly);
void yfsd_UnlockYAFFS(BOOL fsLockOnly);
#endif

#define YAFFS_PASSIVE_GC_CHUNKS 2

#include "yaffs_ecc.h"


/* Robustification (if it ever comes about...) */
static void yaffs_RetireBlock(yaffs_Device * dev, int blockInNAND);
static void yaffs_HandleWriteChunkError(yaffs_Device * dev, int chunkInNAND, int erasedOk);
static void yaffs_HandleWriteChunkOk(yaffs_Device * dev, int chunkInNAND,
				     const __u8 * data,
				     const yaffs_ExtendedTags * tags);
static void yaffs_HandleUpdateChunk(yaffs_Device * dev, int chunkInNAND,
				    const yaffs_ExtendedTags * tags);

/* Other local prototypes */
static int yaffs_UnlinkObject( yaffs_Object *obj);
static int yaffs_ObjectHasCachedWriteData(yaffs_Object *obj);

static void yaffs_HardlinkFixup(yaffs_Device *dev, yaffs_Object *hardList);

static int yaffs_WriteNewChunkWithTagsToNAND(yaffs_Device * dev,
					     const __u8 * buffer,
					     yaffs_ExtendedTags * tags,
					     int useReserve);
static int yaffs_PutChunkIntoFile(yaffs_Object * in, int chunkInInode,
				  int chunkInNAND, int inScan);

static yaffs_Object *yaffs_CreateNewObject(yaffs_Device * dev, int number,
					   yaffs_ObjectType type);
static void yaffs_AddObjectToDirectory(yaffs_Object * directory,
				       yaffs_Object * obj);
static int yaffs_UpdateObjectHeader(yaffs_Object * in, const YCHAR * name,
				    int force, int isShrink, int shadows);
static void yaffs_RemoveObjectFromDirectory(yaffs_Object * obj);
static int yaffs_CheckStructures(void);
static int yaffs_DeleteWorker(yaffs_Object * in, yaffs_Tnode * tn, __u32 level,
			      int chunkOffset, int *limit);
static int yaffs_DoGenericObjectDeletion(yaffs_Object * in);

static yaffs_BlockInfo *yaffs_GetBlockInfo(yaffs_Device * dev, int blockNo);

static __u8 *yaffs_GetTempBuffer(yaffs_Device * dev, int lineNo);
static void yaffs_ReleaseTempBuffer(yaffs_Device * dev, __u8 * buffer,
				    int lineNo);

static int yaffs_CheckChunkErased(struct yaffs_DeviceStruct *dev,
				  int chunkInNAND);

static int yaffs_UnlinkWorker(yaffs_Object * obj);
static void yaffs_DestroyObject(yaffs_Object * obj);

static int yaffs_TagsMatch(const yaffs_ExtendedTags * tags, int objectId,
			   int chunkInObject);

loff_t yaffs_GetFileSize(yaffs_Object * obj);

static int yaffs_AllocateChunk(yaffs_Device * dev, int useReserve, yaffs_BlockInfo **blockUsedPtr);

static void yaffs_VerifyFreeChunks(yaffs_Device * dev);

#ifdef YAFFS_PARANOID
static int yaffs_CheckFileSanity(yaffs_Object * in);
#else
#define yaffs_CheckFileSanity(in)
#endif

static void yaffs_InvalidateWholeChunkCache(yaffs_Object * in);
static void yaffs_InvalidateChunkCache(yaffs_Object * object, int chunkId);

static void yaffs_InvalidateCheckpoint(yaffs_Device *dev);



/* Function to calculate chunk and offset */

static void yaffs_AddrToChunk(yaffs_Device *dev, loff_t addr, __u32 *chunk, __u32 *offset)
{
	if(dev->chunkShift){
		/* Easy-peasy power of 2 case */
		*chunk  = (__u32)(addr >> dev->chunkShift);
		*offset = (__u32)(addr & dev->chunkMask);
	}
	else if(dev->crumbsPerChunk)
	{
		/* Case where we're using "crumbs" */
		*offset = (__u32)(addr & dev->crumbMask);
		addr >>= dev->crumbShift;
		*chunk = ((__u32)addr)/dev->crumbsPerChunk;
		*offset += ((addr - (*chunk * dev->crumbsPerChunk)) << dev->crumbShift);
	}
	else
		YBUG();
}

/* Function to return the number of shifts for a power of 2 greater than or equal 
 * to the given number
 * Note we don't try to cater for all possible numbers and this does not have to
 * be hellishly efficient.
 */
 
static __u32 ShiftsGE(__u32 x)
{
	int extraBits;
	int nShifts;
	
	nShifts = extraBits = 0;
	
	while(x>1){
		if(x & 1) extraBits++;
		x>>=1;
		nShifts++;
	}

	if(extraBits) 
		nShifts++;
		
	return nShifts;
}

/* Function to return the number of shifts to get a 1 in bit 0
 */
 
static __u32 ShiftDiv(__u32 x)
{
	int nShifts;
	
	nShifts =  0;
	
	if(!x) return 0;
	
	while( !(x&1)){
		x>>=1;
		nShifts++;
	}
		
	return nShifts;
}



/* 
 * Temporary buffer manipulations.
 */

static __u8 *yaffs_GetTempBuffer(yaffs_Device * dev, int lineNo)
{
	int i, j;
	for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
		if (dev->tempBuffer[i].line == 0) {
			dev->tempBuffer[i].line = lineNo;
			if ((i + 1) > dev->maxTemp) {
				dev->maxTemp = i + 1;
				for (j = 0; j <= i; j++)
					dev->tempBuffer[j].maxLine =
					    dev->tempBuffer[j].line;
			}

			return dev->tempBuffer[i].buffer;
		}
	}

	T(YAFFS_TRACE_BUFFERS,
	  (TSTR("Out of temp buffers at line %d, other held by lines:"),
	   lineNo));
	for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
		T(YAFFS_TRACE_BUFFERS, (TSTR(" %d "), dev->tempBuffer[i].line));
	}
	T(YAFFS_TRACE_BUFFERS, (TSTR(" " TENDSTR)));

	/*
	 * If we got here then we have to allocate an unmanaged one
	 * This is not good.
	 */

	dev->unmanagedTempAllocations++;
	return YMALLOC(dev->nDataBytesPerChunk);

}

static void yaffs_ReleaseTempBuffer(yaffs_Device * dev, __u8 * buffer,
				    int lineNo)
{
	int i;
	for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
		if (dev->tempBuffer[i].buffer == buffer) {
			dev->tempBuffer[i].line = 0;
			return;
		}
	}

	if (buffer) {
		/* assume it is an unmanaged one. */
		T(YAFFS_TRACE_BUFFERS,
		  (TSTR("Releasing unmanaged temp buffer in line %d" TENDSTR),
		   lineNo));
		YFREE(buffer);
		dev->unmanagedTempDeallocations++;
	}

}

/*
 * Determine if we have a managed buffer.
 */
int yaffs_IsManagedTempBuffer(yaffs_Device * dev, const __u8 * buffer)
{
	int i;
	for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
		if (dev->tempBuffer[i].buffer == buffer)
			return 1;

	}

    for (i = 0; i < dev->nShortOpCaches; i++) {
        if( dev->srCache[i].data == buffer )
            return 1;

    }

    if (buffer == dev->checkpointBuffer)
      return 1;

    T(YAFFS_TRACE_ALWAYS,
	  (TSTR("yaffs: unmaged buffer detected.\n" TENDSTR)));
    return 0;
}

/*
 * Chunk bitmap manipulations
 */

static Y_INLINE __u8 *yaffs_BlockBits(yaffs_Device * dev, int blk)
{
	if (blk < dev->internalStartBlock || blk > dev->internalEndBlock) {
		T(YAFFS_TRACE_ERROR,
		  (TSTR("**>> yaffs: BlockBits block %d is not valid" TENDSTR),
		   blk));
		YBUG();
	}
	return dev->chunkBits +
	    (dev->chunkBitmapStride * (blk - dev->internalStartBlock));
}

static Y_INLINE void yaffs_ClearChunkBits(yaffs_Device * dev, int blk)
{
	__u8 *blkBits = yaffs_BlockBits(dev, blk);

	memset(blkBits, 0, dev->chunkBitmapStride);
}

static Y_INLINE void yaffs_ClearChunkBit(yaffs_Device * dev, int blk, int chunk)
{
	__u8 *blkBits = yaffs_BlockBits(dev, blk);

	blkBits[chunk / 8] &= ~(1 << (chunk & 7));
}

static Y_INLINE void yaffs_SetChunkBit(yaffs_Device * dev, int blk, int chunk)
{
	__u8 *blkBits = yaffs_BlockBits(dev, blk);

	blkBits[chunk / 8] |= (1 << (chunk & 7));
}

static Y_INLINE int yaffs_CheckChunkBit(yaffs_Device * dev, int blk, int chunk)
{
	__u8 *blkBits = yaffs_BlockBits(dev, blk);
	return (blkBits[chunk / 8] & (1 << (chunk & 7))) ? 1 : 0;
}

static Y_INLINE int yaffs_StillSomeChunkBits(yaffs_Device * dev, int blk)
{
	__u8 *blkBits = yaffs_BlockBits(dev, blk);
	int i;
	for (i = 0; i < dev->chunkBitmapStride; i++) {
		if (*blkBits)
			return 1;
		blkBits++;
	}
	return 0;
}

/*
 *  Simple hash function. Needs to have a reasonable spread
 */
 
static Y_INLINE int yaffs_HashFunction(int n)
{
	n = abs(n);
	return (n % YAFFS_NOBJECT_BUCKETS);
}

/*
 * Access functions to useful fake objects
 */
 
yaffs_Object *yaffs_Root(yaffs_Device * dev)
{
	return dev->rootDir;
}

yaffs_Object *yaffs_LostNFound(yaffs_Device * dev)
{
	return dev->lostNFoundDir;
}


/*
 *  Erased NAND checking functions
 */
 
int yaffs_CheckFF(__u8 * buffer, int nBytes)
{
	/* Horrible, slow implementation */
	while (nBytes--) {
		if (*buffer != 0xFF)
			return 0;
		buffer++;
	}
	return 1;
}

static int yaffs_CheckChunkErased(struct yaffs_DeviceStruct *dev,
				  int chunkInNAND)
{

	int retval = YAFFS_OK;
	__u8 *data = yaffs_GetTempBuffer(dev, __LINE__);
	yaffs_ExtendedTags tags;
	int result;

	result = yaffs_ReadChunkWithTagsFromNAND(dev, chunkInNAND, data, &tags);
	
	if(tags.eccResult > YAFFS_ECC_RESULT_NO_ERROR)
		retval = YAFFS_FAIL;
		

	if (!yaffs_CheckFF(data, dev->nDataBytesPerChunk) || tags.chunkUsed) {
		T(YAFFS_TRACE_NANDACCESS,
		  (TSTR("Chunk %d not erased" TENDSTR), chunkInNAND));
		retval = YAFFS_FAIL;
	}

	yaffs_ReleaseTempBuffer(dev, data, __LINE__);

	return retval;

}

static int yaffs_WriteNewChunkWithTagsToNAND(struct yaffs_DeviceStruct *dev,
					     const __u8 * data,
					     yaffs_ExtendedTags * tags,
					     int useReserve)
{
	int chunk;

	int writeOk = 0;
	int erasedOk = 1;
	int attempts = 0;
	yaffs_BlockInfo *bi;
	
	yaffs_InvalidateCheckpoint(dev);

	do {
		chunk = yaffs_AllocateChunk(dev, useReserve,&bi);

		if (chunk >= 0) {
			/* First check this chunk is erased, if it needs checking.
			 * The checking policy (unless forced always on) is as follows:
			 * Check the first page we try to write in a block.
			 * - If the check passes then we don't need to check any more.
			 * - If the check fails, we check again...
			 * If the block has been erased, we don't need to check.
			 *
			 * However, if the block has been prioritised for gc, then
			 * we think there might be something odd about this block
			 * and stop using it.
			 *
			 * Rationale:
			 * We should only ever see chunks that have not been erased
			 * if there was a partially written chunk due to power loss
			 * This checking policy should catch that case with very
			 * few checks and thus save a lot of checks that are most likely not
			 * needed.
			 */
			 
			 if(bi->gcPrioritise){
			 		yaffs_DeleteChunk(dev, chunk, 1, __LINE__);
			} else {
#ifdef CONFIG_YAFFS_ALWAYS_CHECK_CHUNK_ERASED

				bi->skipErasedCheck = 0;

#endif
				if(!bi->skipErasedCheck){
					erasedOk = yaffs_CheckChunkErased(dev, chunk);
					if(erasedOk && !bi->gcPrioritise)
						bi->skipErasedCheck = 1;
				}

				if (!erasedOk) {
					T(YAFFS_TRACE_ERROR,
					  (TSTR
					   ("**>> yaffs chunk %d was not erased"
					    TENDSTR), chunk));
				} else {
					writeOk =
					    yaffs_WriteChunkWithTagsToNAND(dev, chunk,
									   data, tags);
				}
			
				attempts++;

				if (writeOk) {
					/*
					 *  Copy the data into the robustification buffer.
					 *  NB We do this at the end to prevent duplicates in the case of a write error.
					 *  Todo
					 */
					yaffs_HandleWriteChunkOk(dev, chunk, data, tags);
				
				} else {
					/* The erased check or write failed */
					yaffs_HandleWriteChunkError(dev, chunk, erasedOk);
				}
			}
		}

	} while (chunk >= 0 && !writeOk);

	if (attempts > 1) {
		T(YAFFS_TRACE_ERROR,
		  (TSTR("**>> yaffs write required %d attempts" TENDSTR),
		   attempts));
		dev->nRetriedWrites += (attempts - 1);
	}

	return chunk;
}

/*
 * Block retiring for handling a broken block.
 */
 
static void yaffs_RetireBlock(yaffs_Device * dev, int blockInNAND)
{
	yaffs_BlockInfo *bi = yaffs_GetBlockInfo(dev, blockInNAND);

	yaffs_InvalidateCheckpoint(dev);
	
	yaffs_MarkBlockBad(dev, blockInNAND);

	bi->blockState = YAFFS_BLOCK_STATE_DEAD;
	bi->gcPrioritise = 0;
	bi->needsRetiring = 0;

	dev->nRetiredBlocks++;
}

/*
 * Functions for robustisizing TODO
 *
 */
 
static void yaffs_HandleWriteChunkOk(yaffs_Device * dev, int chunkInNAND,
				     const __u8 * data,
				     const yaffs_ExtendedTags * tags)
{
}

static void yaffs_HandleUpdateChunk(yaffs_Device * dev, int chunkInNAND,
				    const yaffs_ExtendedTags * tags)
{
}

void yaffs_HandleChunkError(yaffs_Device *dev, yaffs_BlockInfo *bi)
{
	if(!bi->gcPrioritise){
		bi->gcPrioritise = 1;
		dev->hasPendingPrioritisedGCs = 1;
		bi->chunkErrorStrikes ++;
		
		if(bi->chunkErrorStrikes > 3){
			bi->needsRetiring = 1; /* Too many stikes, so retire this */
			T(YAFFS_TRACE_ALWAYS, (TSTR("yaffs: Block struck out" TENDSTR)));

		}
		
	}
}

static void yaffs_ReportOddballBlocks(yaffs_Device *dev)
{
	int i;
		
	for(i = dev->internalStartBlock; i <= dev->internalEndBlock && (yaffs_traceMask & YAFFS_TRACE_BAD_BLOCKS); i++){
		yaffs_BlockInfo *bi = yaffs_GetBlockInfo(dev,i);
		if(bi->needsRetiring || bi->gcPrioritise)
			T(YAFFS_TRACE_BAD_BLOCKS,(TSTR("yaffs block %d%s%s" TENDSTR),
				i,
				bi->needsRetiring ? " needs retiring" : "",
				bi->gcPrioritise ?  " gc prioritised" : ""));
		
	}