yaffs_guts.c

YAFFS

/*
 * 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 <[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 1.27 2005/12/20 04:02:18 charles Exp $";

#include "yportenv.h"

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

#include "yaffs_tagscompat.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"

/* NAND access */

static Y_INLINE int yaffs_ReadChunkWithTagsFromNAND(yaffs_Device * dev,
						    int chunkInNAND,
						    __u8 * buffer,
						    yaffs_ExtendedTags * tags);
static Y_INLINE int yaffs_WriteChunkWithTagsToNAND(yaffs_Device * dev,
						   int chunkInNAND,
						   const __u8 * data,
						   yaffs_ExtendedTags * tags);
static Y_INLINE int yaffs_MarkBlockBad(yaffs_Device * dev, int blockNo);
static Y_INLINE int yaffs_QueryInitialBlockState(yaffs_Device * dev,
						 int blockNo,
						 yaffs_BlockState * state,
						 unsigned *sequenceNumber);
/* Robustification (if it ever comes about...) */
static void yaffs_RetireBlock(yaffs_Device * dev, int blockInNAND);
static void yaffs_HandleWriteChunkError(yaffs_Device * dev, int chunkInNAND);
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_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);

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);


/*
 *   Start of real code.
 */

/*
 * NAND access layer
 */
 


static int yaffs_ReadChunkWithTagsFromNAND(yaffs_Device * dev, int chunkInNAND,
					   __u8 * buffer,
					   yaffs_ExtendedTags * tags)
{
	chunkInNAND -= dev->chunkOffset;

	if (dev->readChunkWithTagsFromNAND)
		return dev->readChunkWithTagsFromNAND(dev, chunkInNAND, buffer,
						      tags);
	else
		return yaffs_TagsCompatabilityReadChunkWithTagsFromNAND(dev,
									chunkInNAND,
									buffer,
									tags);
}

static Y_INLINE int yaffs_WriteChunkWithTagsToNAND(yaffs_Device * dev,
						   int chunkInNAND,
						   const __u8 * buffer,
						   yaffs_ExtendedTags * tags)
{
	chunkInNAND -= dev->chunkOffset;

	if (tags) {
		tags->sequenceNumber = dev->sequenceNumber;
		tags->chunkUsed = 1;
		if (!yaffs_ValidateTags(tags)) {
			T(YAFFS_TRACE_ERROR,
			  (TSTR("Writing uninitialised tags" TENDSTR)));
			YBUG();
		}
		T(YAFFS_TRACE_WRITE,
		  (TSTR("Writing chunk %d tags %d %d" TENDSTR), chunkInNAND,
		   tags->objectId, tags->chunkId));
	} else {
		T(YAFFS_TRACE_ERROR, (TSTR("Writing with no tags" TENDSTR)));
		YBUG();
	}

	if (dev->writeChunkWithTagsToNAND)
		return dev->writeChunkWithTagsToNAND(dev, chunkInNAND, buffer,
						     tags);
	else
		return yaffs_TagsCompatabilityWriteChunkWithTagsToNAND(dev,
								       chunkInNAND,
								       buffer,
								       tags);
}

static Y_INLINE int yaffs_MarkBlockBad(yaffs_Device * dev, int blockNo)
{
	blockNo -= dev->blockOffset;

	if (dev->markNANDBlockBad)
		return dev->markNANDBlockBad(dev, blockNo);
	else
		return yaffs_TagsCompatabilityMarkNANDBlockBad(dev, blockNo);
}
static Y_INLINE int yaffs_QueryInitialBlockState(yaffs_Device * dev,
						 int blockNo,
						 yaffs_BlockState * state,
						 unsigned *sequenceNumber)
{
	blockNo -= dev->blockOffset;

	if (dev->queryNANDBlock)
		return dev->queryNANDBlock(dev, blockNo, state, sequenceNumber);
	else
		return yaffs_TagsCompatabilityQueryNANDBlock(dev, blockNo,
							     state,
							     sequenceNumber);
}

static int yaffs_EraseBlockInNAND(struct yaffs_DeviceStruct *dev,
				  int blockInNAND)
{
	int result;

	blockInNAND -= dev->blockOffset;

	dev->nBlockErasures++;
	result = dev->eraseBlockInNAND(dev, blockInNAND);

	/* If at first we don't succeed, try again *once*.*/
	if (!result)
		result = dev->eraseBlockInNAND(dev, blockInNAND);	
	return result;
}

static int yaffs_InitialiseNAND(struct yaffs_DeviceStruct *dev)
{
	return dev->initialiseNAND(dev);
}

/* 
 * 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->nBytesPerChunk);

}

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++;
	}

}

/*
 * 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)
{
	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;

	yaffs_ReadChunkWithTagsFromNAND(dev, chunkInNAND, data, &tags);

	if (!yaffs_CheckFF(data, dev->nBytesPerChunk) || 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 = 1;
	int attempts = 0;

	do {
		chunk = yaffs_AllocateChunk(dev, useReserve);

		if (chunk >= 0) {

			/* First check this chunk is erased... */
#ifndef CONFIG_YAFFS_DISABLE_CHUNK_ERASED_CHECK
			writeOk = yaffs_CheckChunkErased(dev, chunk);
#endif
			if (!writeOk) {
				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 {
				yaffs_HandleWriteChunkError(dev, chunk);
			}
		}

	} 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_MarkBlockBad(dev, blockInNAND);

	yaffs_GetBlockInfo(dev, blockInNAND)->blockState =
	    YAFFS_BLOCK_STATE_DEAD;

	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)
{
}

static void yaffs_HandleWriteChunkError(yaffs_Device * dev, int chunkInNAND)
{
	int blockInNAND = chunkInNAND / dev->nChunksPerBlock;

	/* Mark the block for retirement */
	yaffs_GetBlockInfo(dev, blockInNAND)->needsRetiring = 1;
	/* Delete the chunk */
	yaffs_DeleteChunk(dev, chunkInNAND, 1, __LINE__);
}


/*---------------- Name handling functions ------------*/ 

static __u16 yaffs_CalcNameSum(const YCHAR * name)
{
	__u16 sum = 0;
	__u16 i = 1;

	YUCHAR *bname = (YUCHAR *) name;
	if (bname) {
		while ((*bname) && (i <= YAFFS_MAX_NAME_LENGTH)) {

#ifdef CONFIG_YAFFS_CASE_INSENSITIVE
			sum += yaffs_toupper(*bname) * i;
#else
			sum += (*bname) * i;
#endif
			i++;
			bname++;
		}
	}
	return sum;
}

static void yaffs_SetObjectName(yaffs_Object * obj, const YCHAR * name)
{
#ifdef CONFIG_YAFFS_SHORT_NAMES_IN_RAM
	if (name && yaffs_strlen(name) <= YAFFS_SHORT_NAME_LENGTH) {
		yaffs_strcpy(obj->shortName, name);
	} else {
		obj->shortName[0] = _Y('\0');
	}
#endif
	obj->sum = yaffs_CalcNameSum(name);
}

/*-------------------- TNODES -------------------

 * List of spare tnodes
 * The list is hooked together using the first pointer
 * in the tnode.
 */
 
/* yaffs_CreateTnodes creates a bunch more tnodes and
 * adds them to the tnode free list.
 * Don't use this function directly
 */

static int yaffs_CreateTnodes(yaffs_Device * dev, int nTnodes)
{
	int i;
	int tnodeSize;
	yaffs_Tnode *newTnodes;
	__u8 *mem;
	yaffs_Tnode *curr;