/*
 * 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 <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.
 */

/* XXX U-BOOT XXX */
#include <common.h>

const char *yaffs_guts_c_version =
    "$Id: yaffs_guts.c,v 1.52 2007/10/16 00:45:05 charles Exp $";

#include "yportenv.h"
#include "linux/stat.h"

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

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

#include "yaffs_checkptrw.h"

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

#include "malloc.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);

static void yaffs_CheckObjectDetailsLoaded(yaffs_Object *in);

#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);

static int yaffs_FindChunkInFile(yaffs_Object * in, int chunkInInode,
                                 yaffs_ExtendedTags * tags);

static __u32 yaffs_GetChunkGroupBase(yaffs_Device *dev, yaffs_Tnode *tn, unsigned pos);
static yaffs_Tnode *yaffs_FindLevel0Tnode(yaffs_Device * dev,
                                          yaffs_FileStructure * fStruct,
                                          __u32 chunkId);


/* 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 int yaffs_InitialiseTempBuffers(yaffs_Device *dev)
{
        int i;
        __u8 *buf = (__u8 *)1;

        memset(dev->tempBuffer,0,sizeof(dev->tempBuffer));

        for (i = 0; buf && i < YAFFS_N_TEMP_BUFFERS; i++) {
                dev->tempBuffer[i].line = 0;    /* not in use */
                dev->tempBuffer[i].buffer = buf =
                    YMALLOC_DMA(dev->nDataBytesPerChunk);
        }

        return buf ? YAFFS_OK : YAFFS_FAIL;

}

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_VerifyChunkBitId(yaffs_Device *dev, int blk, int chunk)
{
        if(blk < dev->internalStartBlock || blk > dev->internalEndBlock ||
           chunk < 0 || chunk >= dev->nChunksPerBlock) {
           T(YAFFS_TRACE_ERROR,
            (TSTR("**>> yaffs: Chunk Id (%d:%d) invalid"TENDSTR),blk,chunk));
            YBUG();
        }
}

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);

        yaffs_VerifyChunkBitId(dev,blk,chunk);

        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);

        yaffs_VerifyChunkBitId(dev,blk,chunk);

        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);
        yaffs_VerifyChunkBitId(dev,blk,chunk);

        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;
}

static int yaffs_CountChunkBits(yaffs_Device * dev, int blk)
{
        __u8 *blkBits = yaffs_BlockBits(dev, blk);
        int i;
        int n = 0;
        for (i = 0; i < dev->chunkBitmapStride; i++) {
                __u8 x = *blkBits;
                while(x){
                        if(x & 1)
                                n++;
                        x >>=1;
                }

                blkBits++;
        }
        return n;
}

/*
 * Verification code
 */

static int yaffs_SkipVerification(yaffs_Device *dev)
{
        return !(yaffs_traceMask & (YAFFS_TRACE_VERIFY | YAFFS_TRACE_VERIFY_FULL));
}

static int yaffs_SkipFullVerification(yaffs_Device *dev)
{
        return !(yaffs_traceMask & (YAFFS_TRACE_VERIFY_FULL));
}

static int yaffs_SkipNANDVerification(yaffs_Device *dev)
{
        return !(yaffs_traceMask & (YAFFS_TRACE_VERIFY_NAND));
}

static const char * blockStateName[] = {
"Unknown",
"Needs scanning",
"Scanning",
"Empty",
"Allocating",
"Full",
"Dirty",
"Checkpoint",
"Collecting",
"Dead"
};

static void yaffs_VerifyBlock(yaffs_Device *dev,yaffs_BlockInfo *bi,int n)
{
        int actuallyUsed;
        int inUse;

        if(yaffs_SkipVerification(dev))
                return;

        /* Report illegal runtime states */
        if(bi->blockState <0 || bi->blockState >= YAFFS_NUMBER_OF_BLOCK_STATES)
                T(YAFFS_TRACE_VERIFY,(TSTR("Block %d has undefined state %d"TENDSTR),n,bi->blockState));

        switch(bi->blockState){
         case YAFFS_BLOCK_STATE_UNKNOWN:
         case YAFFS_BLOCK_STATE_SCANNING:
         case YAFFS_BLOCK_STATE_NEEDS_SCANNING:
                T(YAFFS_TRACE_VERIFY,(TSTR("Block %d has bad run-state %s"TENDSTR),
                n,blockStateName[bi->blockState]));
        }

        /* Check pages in use and soft deletions are legal */

        actuallyUsed = bi->pagesInUse - bi->softDeletions;

        if(bi->pagesInUse < 0 || bi->pagesInUse > dev->nChunksPerBlock ||
           bi->softDeletions < 0 || bi->softDeletions > dev->nChunksPerBlock ||
           actuallyUsed < 0 || actuallyUsed > dev->nChunksPerBlock)
                T(YAFFS_TRACE_VERIFY,(TSTR("Block %d has illegal values pagesInUsed %d softDeletions %d"TENDSTR),
                n,bi->pagesInUse,bi->softDeletions));


        /* Check chunk bitmap legal */
        inUse = yaffs_CountChunkBits(dev,n);
        if(inUse != bi->pagesInUse)
                T(YAFFS_TRACE_VERIFY,(TSTR("Block %d has inconsistent values pagesInUse %d counted chunk bits %d"TENDSTR),
                        n,bi->pagesInUse,inUse));

        /* Check that the sequence number is valid.
         * Ten million is legal, but is very unlikely
         */
        if(dev->isYaffs2 &&
           (bi->blockState == YAFFS_BLOCK_STATE_ALLOCATING || bi->blockState == YAFFS_BLOCK_STATE_FULL) &&
           (bi->sequenceNumber < YAFFS_LOWEST_SEQUENCE_NUMBER || bi->sequenceNumber > 10000000 ))
                T(YAFFS_TRACE_VERIFY,(TSTR("Block %d has suspect sequence number of %d"TENDSTR),
                n,bi->sequenceNumber));

}

static void yaffs_VerifyCollectedBlock(yaffs_Device *dev,yaffs_BlockInfo *bi,int n)
{
        yaffs_VerifyBlock(dev,bi,n);

        /* After collection the block should be in the erased state */
        /* TODO: This will need to change if we do partial gc */

        if(bi->blockState != YAFFS_BLOCK_STATE_EMPTY){
                T(YAFFS_TRACE_ERROR,(TSTR("Block %d is in state %d after gc, should be erased"TENDSTR),
                        n,bi->blockState));
        }
}

static void yaffs_VerifyBlocks(yaffs_Device *dev)
{
        int i;
        int nBlocksPerState[YAFFS_NUMBER_OF_BLOCK_STATES];
        int nIllegalBlockStates = 0;


        if(yaffs_SkipVerification(dev))
                return;

        memset(nBlocksPerState,0,sizeof(nBlocksPerState));


        for(i = dev->internalStartBlock; i <= dev->internalEndBlock; i++){
                yaffs_BlockInfo *bi = yaffs_GetBlockInfo(dev,i);
                yaffs_VerifyBlock(dev,bi,i);

                if(bi->blockState >=0 && bi->blockState < YAFFS_NUMBER_OF_BLOCK_STATES)
                        nBlocksPerState[bi->blockState]++;
                else
                        nIllegalBlockStates++;

        }

        T(YAFFS_TRACE_VERIFY,(TSTR(""TENDSTR)));
        T(YAFFS_TRACE_VERIFY,(TSTR("Block summary"TENDSTR)));

        T(YAFFS_TRACE_VERIFY,(TSTR("%d blocks have illegal states"TENDSTR),nIllegalBlockStates));
        if(nBlocksPerState[YAFFS_BLOCK_STATE_ALLOCATING] > 1)
                T(YAFFS_TRACE_VERIFY,(TSTR("Too many allocating blocks"TENDSTR)));

        for(i = 0; i < YAFFS_NUMBER_OF_BLOCK_STATES; i++)
                T(YAFFS_TRACE_VERIFY,
                  (TSTR("%s %d blocks"TENDSTR),
                  blockStateName[i],nBlocksPerState[i]));

        if(dev->blocksInCheckpoint != nBlocksPerState[YAFFS_BLOCK_STATE_CHECKPOINT])
                T(YAFFS_TRACE_VERIFY,
                 (TSTR("Checkpoint block count wrong dev %d count %d"TENDSTR),
                 dev->blocksInCheckpoint, nBlocksPerState[YAFFS_BLOCK_STATE_CHECKPOINT]));

        if(dev->nErasedBlocks != nBlocksPerState[YAFFS_BLOCK_STATE_EMPTY])
                T(YAFFS_TRACE_VERIFY,
                 (TSTR("Erased block count wrong dev %d count %d"TENDSTR),
                 dev->nErasedBlocks, nBlocksPerState[YAFFS_BLOCK_STATE_EMPTY]));

        if(nBlocksPerState[YAFFS_BLOCK_STATE_COLLECTING] > 1)
                T(YAFFS_TRACE_VERIFY,
                 (TSTR("Too many collecting blocks %d (max is 1)"TENDSTR),
                 nBlocksPerState[YAFFS_BLOCK_STATE_COLLECTING]));

        T(YAFFS_TRACE_VERIFY,(TSTR(""TENDSTR)));

}

/*
 * Verify the object header. oh must be valid, but obj and tags may be NULL in which
 * case those tests will not be performed.
 */
static void yaffs_VerifyObjectHeader(yaffs_Object *obj, yaffs_ObjectHeader *oh, yaffs_ExtendedTags *tags, int parentCheck)
{
        if(yaffs_SkipVerification(obj->myDev))
                return;

        if(!(tags && obj && oh)){
                T(YAFFS_TRACE_VERIFY,
                                (TSTR("Verifying object header tags %x obj %x oh %x"TENDSTR),
                                (__u32)tags,(__u32)obj,(__u32)oh));
                return;
        }

        if(oh->type <= YAFFS_OBJECT_TYPE_UNKNOWN ||
           oh->type > YAFFS_OBJECT_TYPE_MAX)
                T(YAFFS_TRACE_VERIFY,
                 (TSTR("Obj %d header type is illegal value 0x%x"TENDSTR),
                 tags->objectId, oh->type));

        if(tags->objectId != obj->objectId)
                T(YAFFS_TRACE_VERIFY,
                 (TSTR("Obj %d header mismatch objectId %d"TENDSTR),
                 tags->objectId, obj->objectId));


        /*
         * Check that the object's parent ids match if parentCheck requested.
         *
         * Tests do not apply to the root object.
         */

        if(parentCheck && tags->objectId > 1 && !obj->parent)
                T(YAFFS_TRACE_VERIFY,
                 (TSTR("Obj %d header mismatch parentId %d obj->parent is NULL"TENDSTR),
                 tags->objectId, oh->parentObjectId));


        if(parentCheck && obj->parent &&
           oh->parentObjectId != obj->parent->objectId &&
           (oh->parentObjectId != YAFFS_OBJECTID_UNLINKED ||
            obj->parent->objectId != YAFFS_OBJECTID_DELETED))
                T(YAFFS_TRACE_VERIFY,
                 (TSTR("Obj %d header mismatch parentId %d parentObjectId %d"TENDSTR),
                 tags->objectId, oh->parentObjectId, obj->parent->objectId));


        if(tags->objectId > 1 && oh->name[0] == 0) /* Null name */
                T(YAFFS_TRACE_VERIFY,
                (TSTR("Obj %d header name is NULL"TENDSTR),
                 obj->objectId));

        if(tags->objectId > 1 && ((__u8)(oh->name[0])) == 0xff) /* Trashed name */
                T(YAFFS_TRACE_VERIFY,
                (TSTR("Obj %d header name is 0xFF"TENDSTR),
                 obj->objectId));
}



static int yaffs_VerifyTnodeWorker(yaffs_Object * obj, yaffs_Tnode * tn,
                                        __u32 level, int chunkOffset)
{
        int i;
        yaffs_Device *dev = obj->myDev;
        int ok = 1;

        if (tn) {
                if (level > 0) {

                        for (i = 0; i < YAFFS_NTNODES_INTERNAL && ok; i++){
                                if (tn->internal[i]) {
                                        ok = yaffs_VerifyTnodeWorker(obj,
                                                        tn->internal[i],
                                                        level - 1,
                                                        (chunkOffset<<YAFFS_TNODES_INTERNAL_BITS) + i);
                                }
                        }
                } else if (level == 0) {
                        int i;
                        yaffs_ExtendedTags tags;
                        __u32 objectId = obj->objectId;

                        chunkOffset <<=  YAFFS_TNODES_LEVEL0_BITS;

                        for(i = 0; i < YAFFS_NTNODES_LEVEL0; i++){
                                __u32 theChunk = yaffs_GetChunkGroupBase(dev,tn,i);

                                if(theChunk > 0){
                                        /* T(~0,(TSTR("verifying (%d:%d) %d"TENDSTR),tags.objectId,tags.chunkId,theChunk)); */
                                        yaffs_ReadChunkWithTagsFromNAND(dev,theChunk,NULL, &tags);
                                        if(tags.objectId != objectId || tags.chunkId != chunkOffset){
                                                T(~0,(TSTR("Object %d chunkId %d NAND mismatch chunk %d tags (%d:%d)"TENDSTR),
                                                        objectId, chunkOffset, theChunk,
                                                        tags.objectId, tags.chunkId));
                                        }
                                }
                                chunkOffset++;
                        }
                }
        }

        return ok;

}


static void yaffs_VerifyFile(yaffs_Object *obj)
{
        int requiredTallness;
        int actualTallness;
        __u32 lastChunk;
        __u32 x;
        __u32 i;
        yaffs_Device *dev;
        yaffs_ExtendedTags tags;
        yaffs_Tnode *tn;
        __u32 objectId;

        if(obj && yaffs_SkipVerification(obj->myDev))
                return;

        dev = obj->myDev;
        objectId = obj->objectId;

        /* Check file size is consistent with tnode depth */
        lastChunk =  obj->variant.fileVariant.fileSize / dev->nDataBytesPerChunk + 1;
        x = lastChunk >> YAFFS_TNODES_LEVEL0_BITS;
        requiredTallness = 0;
        while (x> 0) {
                x >>= YAFFS_TNODES_INTERNAL_BITS;
                requiredTallness++;
        }

        actualTallness = obj->variant.fileVariant.topLevel;

        if(requiredTallness > actualTallness )
                T(YAFFS_TRACE_VERIFY,
                (TSTR("Obj %d had tnode tallness %d, needs to be %d"TENDSTR),
                 obj->objectId,actualTallness, requiredTallness));


        /* Check that the chunks in the tnode tree are all correct.
         * We do this by scanning through the tnode tree and
         * checking the tags for every chunk match.
         */

        if(yaffs_SkipNANDVerification(dev))
                return;

        for(i = 1; i <= lastChunk; i++){
                tn = yaffs_FindLevel0Tnode(dev, &obj->variant.fileVariant,i);

                if (tn) {
                        __u32 theChunk = yaffs_GetChunkGroupBase(dev,tn,i);
                        if(theChunk > 0){
                                /* T(~0,(TSTR("verifying (%d:%d) %d"TENDSTR),objectId,i,theChunk)); */
                                yaffs_ReadChunkWithTagsFromNAND(dev,theChunk,NULL, &tags);
                                if(tags.objectId != objectId || tags.chunkId != i){
                                        T(~0,(TSTR("Object %d chunkId %d NAND mismatch chunk %d tags (%d:%d)"TENDSTR),
                                                objectId, i, theChunk,
                                                tags.objectId, tags.chunkId));
                                }
                        }
                }

        }

}

static void yaffs_VerifyDirectory(yaffs_Object *obj)
{
        if(obj && yaffs_SkipVerification(obj->myDev))
                return;

}

static void yaffs_VerifyHardLink(yaffs_Object *obj)
{
        if(obj && yaffs_SkipVerification(obj->myDev))
                return;

        /* Verify sane equivalent object */
}

static void yaffs_VerifySymlink(yaffs_Object *obj)
{
        if(obj && yaffs_SkipVerification(obj->myDev))
                return;

        /* Verify symlink string */
}

static void yaffs_VerifySpecial(yaffs_Object *obj)
{
        if(obj && yaffs_SkipVerification(obj->myDev))
                return;
}

static void yaffs_VerifyObject(yaffs_Object *obj)
{
        yaffs_Device *dev;

        __u32 chunkMin;
        __u32 chunkMax;

        __u32 chunkIdOk;
        __u32 chunkIsLive;

        if(!obj)
                return;

        dev = obj->myDev;

        if(yaffs_SkipVerification(dev))
                return;

        /* Check sane object header chunk */

        chunkMin = dev->internalStartBlock * dev->nChunksPerBlock;
        chunkMax = (dev->internalEndBlock+1) * dev->nChunksPerBlock - 1;

        chunkIdOk = (obj->chunkId >= chunkMin && obj->chunkId <= chunkMax);
        chunkIsLive = chunkIdOk &&
                        yaffs_CheckChunkBit(dev,
                                            obj->chunkId / dev->nChunksPerBlock,
                                            obj->chunkId % dev->nChunksPerBlock);
        if(!obj->fake &&
            (!chunkIdOk || !chunkIsLive)) {
           T(YAFFS_TRACE_VERIFY,
           (TSTR("Obj %d has chunkId %d %s %s"TENDSTR),
           obj->objectId,obj->chunkId,
           chunkIdOk ? "" : ",out of range",
           chunkIsLive || !chunkIdOk ? "" : ",marked as deleted"));
        }

        if(chunkIdOk && chunkIsLive &&!yaffs_SkipNANDVerification(dev)) {
                yaffs_ExtendedTags tags;
                yaffs_ObjectHeader *oh;
                __u8 *buffer = yaffs_GetTempBuffer(dev,__LINE__);

                oh = (yaffs_ObjectHeader *)buffer;

                yaffs_ReadChunkWithTagsFromNAND(dev, obj->chunkId,buffer, &tags);

                yaffs_VerifyObjectHeader(obj,oh,&tags,1);

                yaffs_ReleaseTempBuffer(dev,buffer,__LINE__);
        }

        /* Verify it has a parent */
        if(obj && !obj->fake &&
           (!obj->parent || obj->parent->myDev != dev)){
           T(YAFFS_TRACE_VERIFY,
           (TSTR("Obj %d has parent pointer %p which does not look like an object"TENDSTR),
           obj->objectId,obj->parent));
        }

        /* Verify parent is a directory */
        if(obj->parent && obj->parent->variantType != YAFFS_OBJECT_TYPE_DIRECTORY){
           T(YAFFS_TRACE_VERIFY,
           (TSTR("Obj %d's parent is not a directory (type %d)"TENDSTR),
           obj->objectId,obj->parent->variantType));
        }

        switch(obj->variantType){
        case YAFFS_OBJECT_TYPE_FILE:
                yaffs_VerifyFile(obj);
                break;
        case YAFFS_OBJECT_TYPE_SYMLINK:
                yaffs_VerifySymlink(obj);
                break;
        case YAFFS_OBJECT_TYPE_DIRECTORY:
                yaffs_VerifyDirectory(obj);
                break;
        case YAFFS_OBJECT_TYPE_HARDLINK:
                yaffs_VerifyHardLink(obj);
                break;
        case YAFFS_OBJECT_TYPE_SPECIAL:
                yaffs_VerifySpecial(obj);
                break;
        case YAFFS_OBJECT_TYPE_UNKNOWN:
        default:
                T(YAFFS_TRACE_VERIFY,
                (TSTR("Obj %d has illegaltype %d"TENDSTR),
                obj->objectId,obj->variantType));
                break;
        }


}

static void yaffs_VerifyObjects(yaffs_Device *dev)
{
        yaffs_Object *obj;
        int i;
        struct list_head *lh;

        if(yaffs_SkipVerification(dev))
                return;

        /* Iterate through the objects in each hash entry */

         for(i = 0; i <  YAFFS_NOBJECT_BUCKETS; i++){
                list_for_each(lh, &dev->objectBucket[i].list) {
                        if (lh) {
                                obj = list_entry(lh, yaffs_Object, hashLink);
                                yaffs_VerifyObject(obj);
                        }
                }
         }

}


/*
 *  Simple hash function. Needs to have a reasonable spread
 */

static Y_INLINE int yaffs_HashFunction(int n)
{
/* XXX U-BOOT XXX */
        /*n = abs(n); */
        if (n < 0)
                n = -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 attempts = 0;
        int writeOk = 0;
        int chunk;

        yaffs_InvalidateCheckpoint(dev);

        do {
                yaffs_BlockInfo *bi = 0;
                int erasedOk = 0;

                chunk = yaffs_AllocateChunk(dev, useReserve, &bi);
                if (chunk < 0) {
                        /* no space */
                        break;
                }

                /* 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__);
                        /* try another chunk */
                        continue;
                }

                /* let's give it a try */
                attempts++;

#ifdef CONFIG_YAFFS_ALWAYS_CHECK_CHUNK_ERASED
                bi->skipErasedCheck = 0;
#endif
                if (!bi->skipErasedCheck) {
                        erasedOk = yaffs_CheckChunkErased(dev, chunk);
                        if (erasedOk != YAFFS_OK) {
                                T(YAFFS_TRACE_ERROR,
                                (TSTR ("**>> yaffs chunk %d was not erased"
                                TENDSTR), chunk));

                                /* try another chunk */
                                continue;
                        }
                        bi->skipErasedCheck = 1;
                }

                writeOk = yaffs_WriteChunkWithTagsToNAND(dev, chunk,
                                data, tags);
                if (writeOk != YAFFS_OK) {
                        yaffs_HandleWriteChunkError(dev, chunk, erasedOk);
                        /* try another chunk */
                        continue;
                }

                /* Copy the data into the robustification buffer */
                yaffs_HandleWriteChunkOk(dev, chunk, data, tags);

        } while (writeOk != YAFFS_OK &&
                (yaffs_wr_attempts <= 0 || attempts <= yaffs_wr_attempts));

        if(!writeOk)
                chunk = -1;

        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_HandleWriteChunkError(yaffs_Device * dev, int chunkInNAND, int erasedOk)
{

        int blockInNAND = chunkInNAND / dev->nChunksPerBlock;
        yaffs_BlockInfo *bi = yaffs_GetBlockInfo(dev, blockInNAND);

        yaffs_HandleChunkError(dev,bi);


        if(erasedOk ) {
                /* Was an actual write failure, so mark the block for retirement  */
                bi->needsRetiring = 1;
                T(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
                  (TSTR("**>> Block %d needs retiring" TENDSTR), blockInNAND));


        }

        /* 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/2))) {

#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;
        yaffs_Tnode *next;
        yaffs_TnodeList *tnl;

        if (nTnodes < 1)
                return YAFFS_OK;

        /* Calculate the tnode size in bytes for variable width tnode support.
         * Must be a multiple of 32-bits  */
        tnodeSize = (dev->tnodeWidth * YAFFS_NTNODES_LEVEL0)/8;

        /* make these things */

        newTnodes = YMALLOC(nTnodes * tnodeSize);
        mem = (__u8 *)newTnodes;

        if (!newTnodes) {
                T(YAFFS_TRACE_ERROR,
                  (TSTR("yaffs: Could not allocate Tnodes" TENDSTR)));
                return YAFFS_FAIL;
        }

        /* Hook them into the free list */
#if 0
        for (i = 0; i < nTnodes - 1; i++) {
                newTnodes[i].internal[0] = &newTnodes[i + 1];
#ifdef CONFIG_YAFFS_TNODE_LIST_DEBUG
                newTnodes[i].internal[YAFFS_NTNODES_INTERNAL] = (void *)1;
#endif
        }

        newTnodes[nTnodes - 1].internal[0] = dev->freeTnodes;
#ifdef CONFIG_YAFFS_TNODE_LIST_DEBUG
        newTnodes[nTnodes - 1].internal[YAFFS_NTNODES_INTERNAL] = (void *)1;
#endif
        dev->freeTnodes = newTnodes;
#else
        /* New hookup for wide tnodes */
        for(i = 0; i < nTnodes -1; i++) {
                curr = (yaffs_Tnode *) &mem[i * tnodeSize];
                next = (yaffs_Tnode *) &mem[(i+1) * tnodeSize];
                curr->internal[0] = next;
        }

        curr = (yaffs_Tnode *) &mem[(nTnodes - 1) * tnodeSize];
        curr->internal[0] = dev->freeTnodes;
        dev->freeTnodes = (yaffs_Tnode *)mem;

#endif


        dev->nFreeTnodes += nTnodes;
        dev->nTnodesCreated += nTnodes;

        /* Now add this bunch of tnodes to a list for freeing up.
         * NB If we can't add this to the management list it isn't fatal
         * but it just means we can't free this bunch of tnodes later.
         */

        tnl = YMALLOC(sizeof(yaffs_TnodeList));
        if (!tnl) {
                T(YAFFS_TRACE_ERROR,
                  (TSTR
                   ("yaffs: Could not add tnodes to management list" TENDSTR)));
                   return YAFFS_FAIL;

        } else {
                tnl->tnodes = newTnodes;
                tnl->next = dev->allocatedTnodeList;
                dev->allocatedTnodeList = tnl;
        }

        T(YAFFS_TRACE_ALLOCATE, (TSTR("yaffs: Tnodes added" TENDSTR)));

        return YAFFS_OK;
}

/* GetTnode gets us a clean tnode. Tries to make allocate more if we run out */

static yaffs_Tnode *yaffs_GetTnodeRaw(yaffs_Device * dev)
{
        yaffs_Tnode *tn = NULL;

        /* If there are none left make more */
        if (!dev->freeTnodes) {
                yaffs_CreateTnodes(dev, YAFFS_ALLOCATION_NTNODES);
        }

        if (dev->freeTnodes) {
                tn = dev->freeTnodes;
#ifdef CONFIG_YAFFS_TNODE_LIST_DEBUG
                if (tn->internal[YAFFS_NTNODES_INTERNAL] != (void *)1) {
                        /* Hoosterman, this thing looks like it isn't in the list */
                        T(YAFFS_TRACE_ALWAYS,
                          (TSTR("yaffs: Tnode list bug 1" TENDSTR)));
                }
#endif
                dev->freeTnodes = dev->freeTnodes->internal[0];
                dev->nFreeTnodes--;
        }

        return tn;
}

static yaffs_Tnode *yaffs_GetTnode(yaffs_Device * dev)
{
        yaffs_Tnode *tn = yaffs_GetTnodeRaw(dev);

        if(tn)
                memset(tn, 0, (dev->tnodeWidth * YAFFS_NTNODES_LEVEL0)/8);

        return tn;
}

/* FreeTnode frees up a tnode and puts it back on the free list */
static void yaffs_FreeTnode(yaffs_Device * dev, yaffs_Tnode * tn)
{
        if (tn) {
#ifdef CONFIG_YAFFS_TNODE_LIST_DEBUG
                if (tn->internal[YAFFS_NTNODES_INTERNAL] != 0) {
                        /* Hoosterman, this thing looks like it is already in the list */
                        T(YAFFS_TRACE_ALWAYS,
                          (TSTR("yaffs: Tnode list bug 2" TENDSTR)));
                }
                tn->internal[YAFFS_NTNODES_INTERNAL] = (void *)1;
#endif
                tn->internal[0] = dev->freeTnodes;
                dev->freeTnodes = tn;
                dev->nFreeTnodes++;
        }
}

static void yaffs_DeinitialiseTnodes(yaffs_Device * dev)
{
        /* Free the list of allocated tnodes */
        yaffs_TnodeList *tmp;

        while (dev->allocatedTnodeList) {
                tmp = dev->allocatedTnodeList->next;

                YFREE(dev->allocatedTnodeList->tnodes);
                YFREE(dev->allocatedTnodeList);
                dev->allocatedTnodeList = tmp;

        }

        dev->freeTnodes = NULL;
        dev->nFreeTnodes = 0;
}

static void yaffs_InitialiseTnodes(yaffs_Device * dev)
{
        dev->allocatedTnodeList = NULL;
        dev->freeTnodes = NULL;
        dev->nFreeTnodes = 0;
        dev->nTnodesCreated = 0;

}


void yaffs_PutLevel0Tnode(yaffs_Device *dev, yaffs_Tnode *tn, unsigned pos, unsigned val)
{
  __u32 *map = (__u32 *)tn;
  __u32 bitInMap;
  __u32 bitInWord;
  __u32 wordInMap;
  __u32 mask;

  pos &= YAFFS_TNODES_LEVEL0_MASK;
  val >>= dev->chunkGroupBits;

  bitInMap = pos * dev->tnodeWidth;
  wordInMap = bitInMap /32;
  bitInWord = bitInMap & (32 -1);

  mask = dev->tnodeMask << bitInWord;

  map[wordInMap] &= ~mask;
  map[wordInMap] |= (mask & (val << bitInWord));

  if(dev->tnodeWidth > (32-bitInWord)) {
    bitInWord = (32 - bitInWord);
    wordInMap++;;
    mask = dev->tnodeMask >> (/*dev->tnodeWidth -*/ bitInWord);
    map[wordInMap] &= ~mask;
    map[wordInMap] |= (mask & (val >> bitInWord));
  }
}

static __u32 yaffs_GetChunkGroupBase(yaffs_Device *dev, yaffs_Tnode *tn, unsigned pos)
{
  __u32 *map = (__u32 *)tn;
  __u32 bitInMap;
  __u32 bitInWord;
  __u32 wordInMap;
  __u32 val;

  pos &= YAFFS_TNODES_LEVEL0_MASK;

  bitInMap = pos * dev->tnodeWidth;
  wordInMap = bitInMap /32;
  bitInWord = bitInMap & (32 -1);

  val = map[wordInMap] >> bitInWord;

  if(dev->tnodeWidth > (32-bitInWord)) {
    bitInWord = (32 - bitInWord);
    wordInMap++;;
    val |= (map[wordInMap] << bitInWord);
  }

  val &= dev->tnodeMask;
  val <<= dev->chunkGroupBits;

  return val;
}

/* ------------------- End of individual tnode manipulation -----------------*/

/* ---------Functions to manipulate the look-up tree (made up of tnodes) ------
 * The look up tree is represented by the top tnode and the number of topLevel
 * in the tree. 0 means only the level 0 tnode is in the tree.
 */

/* FindLevel0Tnode finds the level 0 tnode, if one exists. */
static yaffs_Tnode *yaffs_FindLevel0Tnode(yaffs_Device * dev,
                                          yaffs_FileStructure * fStruct,
                                          __u32 chunkId)
{

        yaffs_Tnode *tn = fStruct->top;
        __u32 i;
        int requiredTallness;
        int level = fStruct->topLevel;

        /* Check sane level and chunk Id */
        if (level < 0 || level > YAFFS_TNODES_MAX_LEVEL) {
                return NULL;
        }

        if (chunkId > YAFFS_MAX_CHUNK_ID) {
                return NULL;
        }

        /* First check we're tall enough (ie enough topLevel) */

        i = chunkId >> YAFFS_TNODES_LEVEL0_BITS;
        requiredTallness = 0;
        while (i) {
                i >>= YAFFS_TNODES_INTERNAL_BITS;
                requiredTallness++;
        }

        if (requiredTallness > fStruct->topLevel) {
                /* Not tall enough, so we can't find it, return NULL. */
                return NULL;
        }

        /* Traverse down to level 0 */
        while (level > 0 && tn) {
                tn = tn->
                    internal[(chunkId >>
                               ( YAFFS_TNODES_LEVEL0_BITS +
                                 (level - 1) *
                                 YAFFS_TNODES_INTERNAL_BITS)
                              ) &
                             YAFFS_TNODES_INTERNAL_MASK];
                level--;

        }

        return tn;
}

/* AddOrFindLevel0Tnode finds the level 0 tnode if it exists, otherwise first expands the tree.
 * This happens in two steps:
 *  1. If the tree isn't tall enough, then make it taller.
 *  2. Scan down the tree towards the level 0 tnode adding tnodes if required.
 *
 * Used when modifying the tree.
 *
 *  If the tn argument is NULL, then a fresh tnode will be added otherwise the specified tn will
 *  be plugged into the ttree.
 */

static yaffs_Tnode *yaffs_AddOrFindLevel0Tnode(yaffs_Device * dev,
                                               yaffs_FileStructure * fStruct,
                                               __u32 chunkId,
                                               yaffs_Tnode *passedTn)
{

        int requiredTallness;
        int i;
        int l;
        yaffs_Tnode *tn;

        __u32 x;


        /* Check sane level and page Id */
        if (fStruct->topLevel < 0 || fStruct->topLevel > YAFFS_TNODES_MAX_LEVEL) {
                return NULL;
        }

        if (chunkId > YAFFS_MAX_CHUNK_ID) {
                return NULL;
        }

        /* First check we're tall enough (ie enough topLevel) */

        x = chunkId >> YAFFS_TNODES_LEVEL0_BITS;
        requiredTallness = 0;
        while (x) {
                x >>= YAFFS_TNODES_INTERNAL_BITS;
                requiredTallness++;
        }


        if (requiredTallness > fStruct->topLevel) {
                /* Not tall enough,gotta make the tree taller */
                for (i = fStruct->topLevel; i < requiredTallness; i++) {

                        tn = yaffs_GetTnode(dev);

                        if (tn) {
                                tn->internal[0] = fStruct->top;
                                fStruct->top = tn;
                        } else {
                                T(YAFFS_TRACE_ERROR,
                                  (TSTR("yaffs: no more tnodes" TENDSTR)));
                        }
                }

                fStruct->topLevel = requiredTallness;
        }

        /* Traverse down to level 0, adding anything we need */

        l = fStruct->topLevel;
        tn = fStruct->top;

        if(l > 0) {
                while (l > 0 && tn) {
                        x = (chunkId >>
                             ( YAFFS_TNODES_LEVEL0_BITS +
                              (l - 1) * YAFFS_TNODES_INTERNAL_BITS)) &
                            YAFFS_TNODES_INTERNAL_MASK;


                        if((l>1) && !tn->internal[x]){
                                /* Add missing non-level-zero tnode */
                                tn->internal[x] = yaffs_GetTnode(dev);

                        } else if(l == 1) {
                                /* Looking from level 1 at level 0 */
                                if (passedTn) {
                                        /* If we already have one, then release it.*/
                                        if(tn->internal[x])
                                                yaffs_FreeTnode(dev,tn->internal[x]);
                                        tn->internal[x] = passedTn;

                                } else if(!tn->internal[x]) {
                                        /* Don't have one, none passed in */
                                        tn->internal[x] = yaffs_GetTnode(dev);
                                }
                        }

                        tn = tn->internal[x];
                        l--;
                }
        } else {
                /* top is level 0 */
                if(passedTn) {
                        memcpy(tn,passedTn,(dev->tnodeWidth * YAFFS_NTNODES_LEVEL0)/8);
                        yaffs_FreeTnode(dev,passedTn);
                }
        }

        return tn;
}

static int yaffs_FindChunkInGroup(yaffs_Device * dev, int theChunk,
                                  yaffs_ExtendedTags * tags, int objectId,
                                  int chunkInInode)
{
        int j;

        for (j = 0; theChunk && j < dev->chunkGroupSize; j++) {
                if (yaffs_CheckChunkBit
                    (dev, theChunk / dev->nChunksPerBlock,
                     theChunk % dev->nChunksPerBlock)) {
                        yaffs_ReadChunkWithTagsFromNAND(dev, theChunk, NULL,
                                                        tags);
                        if (yaffs_TagsMatch(tags, objectId, chunkInInode)) {
                                /* found it; */
                                return theChunk;

                        }
                }
                theChunk++;
        }
        return -1;
}


/* DeleteWorker scans backwards through the tnode tree and deletes all the
 * chunks and tnodes in the file
 * Returns 1 if the tree was deleted.
 * Returns 0 if it stopped early due to hitting the limit and the delete is incomplete.
 */

static int yaffs_DeleteWorker(yaffs_Object * in, yaffs_Tnode * tn, __u32 level,
                              int chunkOffset, int *limit)
{
        int i;
        int chunkInInode;
        int theChunk;
        yaffs_ExtendedTags tags;
        int foundChunk;
        yaffs_Device *dev = in->myDev;

        int allDone = 1;

        if (tn) {
                if (level > 0) {

                        for (i = YAFFS_NTNODES_INTERNAL - 1; allDone && i >= 0;
                             i--) {
                                if (tn->internal[i]) {
                                        if (limit && (*limit) < 0) {
                                                allDone = 0;
                                        } else {
                                                allDone =
                                                    yaffs_DeleteWorker(in,
                                                                       tn->
                                                                       internal
                                                                       [i],
                                                                       level -
                                                                       1,
                                                                       (chunkOffset
                                                                        <<
                                                                        YAFFS_TNODES_INTERNAL_BITS)
                                                                       + i,
                                                                       limit);
                                        }
                                        if (allDone) {
                                                yaffs_FreeTnode(dev,
                                                                tn->
                                                                internal[i]);
                                                tn->internal[i] = NULL;
                                        }
                                }

                        }
                        return (allDone) ? 1 : 0;
                } else if (level == 0) {
                        int hitLimit = 0;

                        for (i = YAFFS_NTNODES_LEVEL0 - 1; i >= 0 && !hitLimit;
                             i--) {
                                theChunk = yaffs_GetChunkGroupBase(dev,tn,i);
                                if (theChunk) {

                                        chunkInInode =
                                            (chunkOffset <<
                                             YAFFS_TNODES_LEVEL0_BITS) + i;

                                        foundChunk =
                                            yaffs_FindChunkInGroup(dev,
                                                                   theChunk,
                                                                   &tags,
                                                                   in->objectId,
                                                                   chunkInInode);

                                        if (foundChunk > 0) {
                                                yaffs_DeleteChunk(dev,
                                                                  foundChunk, 1,
                                                                  __LINE__);
                                                in->nDataChunks--;
                                                if (limit) {
                                                        *limit = *limit - 1;
                                                        if (*limit <= 0) {
                                                                hitLimit = 1;
                                                        }
                                                }

                                        }

                                        yaffs_PutLevel0Tnode(dev,tn,i,0);
                                }

                        }
                        return (i < 0) ? 1 : 0;

                }

        }

        return 1;

}

static void yaffs_SoftDeleteChunk(yaffs_Device * dev, int chunk)
{

        yaffs_BlockInfo *theBlock;

        T(YAFFS_TRACE_DELETION, (TSTR("soft delete chunk %d" TENDSTR), chunk));

        theBlock = yaffs_GetBlockInfo(dev, chunk / dev->nChunksPerBlock);
        if (theBlock) {
                theBlock->softDeletions++;
                dev->nFreeChunks++;
        }
}

/* SoftDeleteWorker scans backwards through the tnode tree and soft deletes all the chunks in the file.
 * All soft deleting does is increment the block's softdelete count and pulls the chunk out
 * of the tnode.
 * Thus, essentially this is the same as DeleteWorker except that the chunks are soft deleted.
 */

static int yaffs_SoftDeleteWorker(yaffs_Object * in, yaffs_Tnode * tn,
                                  __u32 level, int chunkOffset)
{
        int i;
        int theChunk;
        int allDone = 1;
        yaffs_Device *dev = in->myDev;

        if (tn) {
                if (level > 0) {

                        for (i = YAFFS_NTNODES_INTERNAL - 1; allDone && i >= 0;
                             i--) {
                                if (tn->internal[i]) {
                                        allDone =
                                            yaffs_SoftDeleteWorker(in,
                                                                   tn->
                                                                   internal[i],
                                                                   level - 1,
                                                                   (chunkOffset
                                                                    <<
                                                                    YAFFS_TNODES_INTERNAL_BITS)
                                                                   + i);
                                        if (allDone) {
                                                yaffs_FreeTnode(dev,
                                                                tn->
                                                                internal[i]);
                                                tn->internal[i] = NULL;
                                        } else {
                                                /* Hoosterman... how could this happen? */
                                        }
                                }
                        }
                        return (allDone) ? 1 : 0;
                } else if (level == 0) {

                        for (i = YAFFS_NTNODES_LEVEL0 - 1; i >= 0; i--) {
                                theChunk = yaffs_GetChunkGroupBase(dev,tn,i);
                                if (theChunk) {
                                        /* Note this does not find the real chunk, only the chunk group.
                                         * We make an assumption that a chunk group is not larger than
                                         * a block.
                                         */
                                        yaffs_SoftDeleteChunk(dev, theChunk);
                                        yaffs_PutLevel0Tnode(dev,tn,i,0);
                                }

                        }
                        return 1;

                }

        }

        return 1;

}

static void yaffs_SoftDeleteFile(yaffs_Object * obj)
{
        if (obj->deleted &&
            obj->variantType == YAFFS_OBJECT_TYPE_FILE && !obj->softDeleted) {
                if (obj->nDataChunks <= 0) {
                        /* Empty file with no duplicate object headers, just delete it immediately */
                        yaffs_FreeTnode(obj->myDev,
                                        obj->variant.fileVariant.top);
                        obj->variant.fileVariant.top = NULL;
                        T(YAFFS_TRACE_TRACING,
                          (TSTR("yaffs: Deleting empty file %d" TENDSTR),
                           obj->objectId));
                        yaffs_DoGenericObjectDeletion(obj);
                } else {
                        yaffs_SoftDeleteWorker(obj,
                                               obj->variant.fileVariant.top,
                                               obj->variant.fileVariant.
                                               topLevel, 0);
                        obj->softDeleted = 1;
                }
        }
}

/* Pruning removes any part of the file structure tree that is beyond the
 * bounds of the file (ie that does not point to chunks).
 *
 * A file should only get pruned when its size is reduced.
 *
 * Before pruning, the chunks must be pulled from the tree and the
 * level 0 tnode entries must be zeroed out.
 * Could also use this for file deletion, but that's probably better handled
 * by a special case.
 */

static yaffs_Tnode *yaffs_PruneWorker(yaffs_Device * dev, yaffs_Tnode * tn,
                                      __u32 level, int del0)
{
        int i;
        int hasData;

        if (tn) {
                hasData = 0;

                for (i = 0; i < YAFFS_NTNODES_INTERNAL; i++) {
                        if (tn->internal[i] && level > 0) {
                                tn->internal[i] =
                                    yaffs_PruneWorker(dev, tn->internal[i],
                                                      level - 1,
                                                      (i == 0) ? del0 : 1);
                        }

                        if (tn->internal[i]) {
                                hasData++;
                        }
                }

                if (hasData == 0 && del0) {
                        /* Free and return NULL */

                        yaffs_FreeTnode(dev, tn);
                        tn = NULL;
                }

        }

        return tn;

}

static int yaffs_PruneFileStructure(yaffs_Device * dev,
                                    yaffs_FileStructure * fStruct)
{
        int i;
        int hasData;
        int done = 0;
        yaffs_Tnode *tn;

        if (fStruct->topLevel > 0) {
                fStruct->top =
                    yaffs_PruneWorker(dev, fStruct->top, fStruct->topLevel, 0);

                /* Now we have a tree with all the non-zero branches NULL but the height
                 * is the same as it was.
                 * Let's see if we can trim internal tnodes to shorten the tree.
                 * We can do this if only the 0th element in the tnode is in use
                 * (ie all the non-zero are NULL)
                 */

                while (fStruct->topLevel && !done) {
                        tn = fStruct->top;

                        hasData = 0;
                        for (i = 1; i < YAFFS_NTNODES_INTERNAL; i++) {
                                if (tn->internal[i]) {
                                        hasData++;
                                }
                        }

                        if (!hasData) {
                                fStruct->top = tn->internal[0];
                                fStruct->topLevel--;
                                yaffs_FreeTnode(dev, tn);
                        } else {
                                done = 1;
                        }
                }
        }

        return YAFFS_OK;
}

/*-------------------- End of File Structure functions.-------------------*/

/* yaffs_CreateFreeObjects creates a bunch more objects and
 * adds them to the object free list.
 */
static int yaffs_CreateFreeObjects(yaffs_Device * dev, int nObjects)
{
        int i;
        yaffs_Object *newObjects;
        yaffs_ObjectList *list;

        if (nObjects < 1)
                return YAFFS_OK;

        /* make these things */
        newObjects = YMALLOC(nObjects * sizeof(yaffs_Object));
        list = YMALLOC(sizeof(yaffs_ObjectList));

        if (!newObjects || !list) {
                if(newObjects)
                        YFREE(newObjects);
                if(list)
                        YFREE(list);
                T(YAFFS_TRACE_ALLOCATE,
                  (TSTR("yaffs: Could not allocate more objects" TENDSTR)));
                return YAFFS_FAIL;
        }

        /* Hook them into the free list */
        for (i = 0; i < nObjects - 1; i++) {
                newObjects[i].siblings.next =
                    (struct list_head *)(&newObjects[i + 1]);
        }

        newObjects[nObjects - 1].siblings.next = (void *)dev->freeObjects;
        dev->freeObjects = newObjects;
        dev->nFreeObjects += nObjects;
        dev->nObjectsCreated += nObjects;

        /* Now add this bunch of Objects to a list for freeing up. */

        list->objects = newObjects;
        list->next = dev->allocatedObjectList;
        dev->allocatedObjectList = list;

        return YAFFS_OK;
}


/* AllocateEmptyObject gets us a clean Object. Tries to make allocate more if we run out */
static yaffs_Object *yaffs_AllocateEmptyObject(yaffs_Device * dev)
{
        yaffs_Object *tn = NULL;

        /* If there are none left make more */
        if (!dev->freeObjects) {
                yaffs_CreateFreeObjects(dev, YAFFS_ALLOCATION_NOBJECTS);
        }

        if (dev->freeObjects) {
                tn = dev->freeObjects;
                dev->freeObjects =
                    (yaffs_Object *) (dev->freeObjects->siblings.next);
                dev->nFreeObjects--;

                /* Now sweeten it up... */

                memset(tn, 0, sizeof(yaffs_Object));
                tn->myDev = dev;
                tn->chunkId = -1;
                tn->variantType = YAFFS_OBJECT_TYPE_UNKNOWN;
                INIT_LIST_HEAD(&(tn->hardLinks));
                INIT_LIST_HEAD(&(tn->hashLink));
                INIT_LIST_HEAD(&tn->siblings);

                /* Add it to the lost and found directory.
                 * NB Can't put root or lostNFound in lostNFound so
                 * check if lostNFound exists first
                 */
                if (dev->lostNFoundDir) {
                        yaffs_AddObjectToDirectory(dev->lostNFoundDir, tn);
                }
        }

        return tn;
}

static yaffs_Object *yaffs_CreateFakeDirectory(yaffs_Device * dev, int number,
                                               __u32 mode)
{

        yaffs_Object *obj =
            yaffs_CreateNewObject(dev, number, YAFFS_OBJECT_TYPE_DIRECTORY);
        if (obj) {
                obj->fake = 1;          /* it is fake so it has no NAND presence... */
                obj->renameAllowed = 0; /* ... and we're not allowed to rename it... */
                obj->unlinkAllowed = 0; /* ... or unlink it */
                obj->deleted = 0;
                obj->unlinked = 0;
                obj->yst_mode = mode;
                obj->myDev = dev;
                obj->chunkId = 0;       /* Not a valid chunk. */
        }

        return obj;

}

static void yaffs_UnhashObject(yaffs_Object * tn)
{
        int bucket;
        yaffs_Device *dev = tn->myDev;

        /* If it is still linked into the bucket list, free from the list */
        if (!list_empty(&tn->hashLink)) {
                list_del_init(&tn->hashLink);
                bucket = yaffs_HashFunction(tn->objectId);
                dev->objectBucket[bucket].count--;
        }

}

/*  FreeObject frees up a Object and puts it back on the free list */
static void yaffs_FreeObject(yaffs_Object * tn)
{

        yaffs_Device *dev = tn->myDev;

/* XXX U-BOOT XXX */
#if 0
#ifdef  __KERNEL__
        if (tn->myInode) {
                /* We're still hooked up to a cached inode.
                 * Don't delete now, but mark for later deletion
                 */
                tn->deferedFree = 1;
                return;
        }
#endif
#endif
        yaffs_UnhashObject(tn);

        /* Link into the free list. */
        tn->siblings.next = (struct list_head *)(dev->freeObjects);
        dev->freeObjects = tn;
        dev->nFreeObjects++;
}

/* XXX U-BOOT XXX */
#if 0
#ifdef __KERNEL__

void yaffs_HandleDeferedFree(yaffs_Object * obj)
{
        if (obj->deferedFree) {
                yaffs_FreeObject(obj);
        }
}

#endif
#endif

static void yaffs_DeinitialiseObjects(yaffs_Device * dev)
{
        /* Free the list of allocated Objects */

        yaffs_ObjectList *tmp;

        while (dev->allocatedObjectList) {
                tmp = dev->allocatedObjectList->next;
                YFREE(dev->allocatedObjectList->objects);
                YFREE(dev->allocatedObjectList);

                dev->allocatedObjectList = tmp;
        }

        dev->freeObjects = NULL;
        dev->nFreeObjects = 0;
}

static void yaffs_InitialiseObjects(yaffs_Device * dev)
{
        int i;

        dev->allocatedObjectList = NULL;
        dev->freeObjects = NULL;
        dev->nFreeObjects = 0;

        for (i = 0; i < YAFFS_NOBJECT_BUCKETS; i++) {
                INIT_LIST_HEAD(&dev->objectBucket[i].list);
                dev->objectBucket[i].count = 0;
        }

}

static int yaffs_FindNiceObjectBucket(yaffs_Device * dev)
{
        static int x = 0;
        int i;
        int l = 999;
        int lowest = 999999;

        /* First let's see if we can find one that's empty. */

        for (i = 0; i < 10 && lowest > 0; i++) {
                x++;
                x %= YAFFS_NOBJECT_BUCKETS;
                if (dev->objectBucket[x].count < lowest) {
                        lowest = dev->objectBucket[x].count;
                        l = x;
                }

        }

        /* If we didn't find an empty list, then try
         * looking a bit further for a short one
         */

        for (i = 0; i < 10 && lowest > 3; i++) {
                x++;
                x %= YAFFS_NOBJECT_BUCKETS;
                if (dev->objectBucket[x].count < lowest) {
                        lowest = dev->objectBucket[x].count;
                        l = x;
                }

        }

        return l;
}

static int yaffs_CreateNewObjectNumber(yaffs_Device * dev)
{
        int bucket = yaffs_FindNiceObjectBucket(dev);

        /* Now find an object value that has not already been taken
         * by scanning the list.
         */

        int found = 0;
        struct list_head *i;

        __u32 n = (__u32) bucket;

        /* yaffs_CheckObjectHashSanity();  */

        while (!found) {
                found = 1;
                n += YAFFS_NOBJECT_BUCKETS;
                if (1 || dev->objectBucket[bucket].count > 0) {
                        list_for_each(i, &dev->objectBucket[bucket].list) {
                                /* If there is already one in the list */
                                if (i
                                    && list_entry(i, yaffs_Object,
                                                  hashLink)->objectId == n) {
                                        found = 0;
                                }
                        }
                }
        }


        return n;
}

static void yaffs_HashObject(yaffs_Object * in)
{
        int bucket = yaffs_HashFunction(in->objectId);
        yaffs_Device *dev = in->myDev;

        list_add(&in->hashLink, &dev->objectBucket[bucket].list);
        dev->objectBucket[bucket].count++;

}

yaffs_Object *yaffs_FindObjectByNumber(yaffs_Device * dev, __u32 number)
{
        int bucket = yaffs_HashFunction(number);
        struct list_head *i;
        yaffs_Object *in;

        list_for_each(i, &dev->objectBucket[bucket].list) {
                /* Look if it is in the list */
                if (i) {
                        in = list_entry(i, yaffs_Object, hashLink);
                        if (in->objectId == number) {
/* XXX U-BOOT XXX */
#if 0
#ifdef __KERNEL__
                                /* Don't tell the VFS about this one if it is defered free */
                                if (in->deferedFree)
                                        return NULL;
#endif
#endif
                                return in;
                        }
                }
        }

        return NULL;
}

yaffs_Object *yaffs_CreateNewObject(yaffs_Device * dev, int number,
                                    yaffs_ObjectType type)
{

        yaffs_Object *theObject;
        yaffs_Tnode *tn;

        if (number < 0) {
                number = yaffs_CreateNewObjectNumber(dev);
        }

        theObject = yaffs_AllocateEmptyObject(dev);
        if(!theObject)
                return NULL;

        if(type == YAFFS_OBJECT_TYPE_FILE){
                tn = yaffs_GetTnode(dev);
                if(!tn){
                        yaffs_FreeObject(theObject);
                        return NULL;
                }
        }



        if (theObject) {
                theObject->fake = 0;
                theObject->renameAllowed = 1;
                theObject->unlinkAllowed = 1;
                theObject->objectId = number;
                yaffs_HashObject(theObject);
                theObject->variantType = type;
#ifdef CONFIG_YAFFS_WINCE
                yfsd_WinFileTimeNow(theObject->win_atime);
                theObject->win_ctime[0] = theObject->win_mtime[0] =
                    theObject->win_atime[0];
                theObject->win_ctime[1] = theObject->win_mtime[1] =
                    theObject->win_atime[1];

#else

                theObject->yst_atime = theObject->yst_mtime =
                    theObject->yst_ctime = Y_CURRENT_TIME;
#endif
                switch (type) {
                case YAFFS_OBJECT_TYPE_FILE:
                        theObject->variant.fileVariant.fileSize = 0;
                        theObject->variant.fileVariant.scannedFileSize = 0;
                        theObject->variant.fileVariant.shrinkSize = 0xFFFFFFFF; /* max __u32 */
                        theObject->variant.fileVariant.topLevel = 0;
                        theObject->variant.fileVariant.top = tn;
                        break;
                case YAFFS_OBJECT_TYPE_DIRECTORY:
                        INIT_LIST_HEAD(&theObject->variant.directoryVariant.
                                       children);
                        break;
                case YAFFS_OBJECT_TYPE_SYMLINK:
                case YAFFS_OBJECT_TYPE_HARDLINK:
                case YAFFS_OBJECT_TYPE_SPECIAL:
                        /* No action required */
                        break;
                case YAFFS_OBJECT_TYPE_UNKNOWN:
                        /* todo this should not happen */
                        break;
                }
        }

        return theObject;
}

static yaffs_Object *yaffs_FindOrCreateObjectByNumber(yaffs_Device * dev,
                                                      int number,
                                                      yaffs_ObjectType type)
{
        yaffs_Object *theObject = NULL;

        if (number > 0) {
                theObject = yaffs_FindObjectByNumber(dev, number);
        }

        if (!theObject) {
                theObject = yaffs_CreateNewObject(dev, number, type);
        }

        return theObject;

}


static YCHAR *yaffs_CloneString(const YCHAR * str)
{
        YCHAR *newStr = NULL;

        if (str && *str) {
                newStr = YMALLOC((yaffs_strlen(str) + 1) * sizeof(YCHAR));
                if(newStr)
                        yaffs_strcpy(newStr, str);
        }

        return newStr;

}

/*
 * Mknod (create) a new object.
 * equivalentObject only has meaning for a hard link;
 * aliasString only has meaning for a sumlink.
 * rdev only has meaning for devices (a subset of special objects)
 */

static yaffs_Object *yaffs_MknodObject(yaffs_ObjectType type,
                                       yaffs_Object * parent,
                                       const YCHAR * name,
                                       __u32 mode,
                                       __u32 uid,
                                       __u32 gid,
                                       yaffs_Object * equivalentObject,
                                       const YCHAR * aliasString, __u32 rdev)
{
        yaffs_Object *in;
        YCHAR *str;

        yaffs_Device *dev = parent->myDev;

        /* Check if the entry exists. If it does then fail the call since we don't want a dup.*/
        if (yaffs_FindObjectByName(parent, name)) {
                return NULL;
        }

        in = yaffs_CreateNewObject(dev, -1, type);

        if(type == YAFFS_OBJECT_TYPE_SYMLINK){
                str = yaffs_CloneString(aliasString);
                if(!str){
                        yaffs_FreeObject(in);
                        return NULL;
                }
        }



        if (in) {
                in->chunkId = -1;
                in->valid = 1;
                in->variantType = type;

                in->yst_mode = mode;

#ifdef CONFIG_YAFFS_WINCE
                yfsd_WinFileTimeNow(in->win_atime);
                in->win_ctime[0] = in->win_mtime[0] = in->win_atime[0];
                in->win_ctime[1] = in->win_mtime[1] = in->win_atime[1];

#else
                in->yst_atime = in->yst_mtime = in->yst_ctime = Y_CURRENT_TIME;

                in->yst_rdev = rdev;
                in->yst_uid = uid;
                in->yst_gid = gid;
#endif
                in->nDataChunks = 0;

                yaffs_SetObjectName(in, name);
                in->dirty = 1;

                yaffs_AddObjectToDirectory(parent, in);

                in->myDev = parent->myDev;

                switch (type) {
                case YAFFS_OBJECT_TYPE_SYMLINK:
                        in->variant.symLinkVariant.alias = str;
                        break;
                case YAFFS_OBJECT_TYPE_HARDLINK:
                        in->variant.hardLinkVariant.equivalentObject =
                            equivalentObject;
                        in->variant.hardLinkVariant.equivalentObjectId =
                            equivalentObject->objectId;
                        list_add(&in->hardLinks, &equivalentObject->hardLinks);
                        break;
                case YAFFS_OBJECT_TYPE_FILE:
                case YAFFS_OBJECT_TYPE_DIRECTORY:
                case YAFFS_OBJECT_TYPE_SPECIAL:
                case YAFFS_OBJECT_TYPE_UNKNOWN:
                        /* do nothing */
                        break;
                }

                if (yaffs_UpdateObjectHeader(in, name, 0, 0, 0) < 0) {
                        /* Could not create the object header, fail the creation */
                        yaffs_DestroyObject(in);
                        in = NULL;
                }

        }

        return in;
}

yaffs_Object *yaffs_MknodFile(yaffs_Object * parent, const YCHAR * name,
                              __u32 mode, __u32 uid, __u32 gid)
{
        return yaffs_MknodObject(YAFFS_OBJECT_TYPE_FILE, parent, name, mode,
                                 uid, gid, NULL, NULL, 0);
}

yaffs_Object *yaffs_MknodDirectory(yaffs_Object * parent, const YCHAR * name,
                                   __u32 mode, __u32 uid, __u32 gid)
{
        return yaffs_MknodObject(YAFFS_OBJECT_TYPE_DIRECTORY, parent, name,
                                 mode, uid, gid, NULL, NULL, 0);
}

yaffs_Object *yaffs_MknodSpecial(yaffs_Object * parent, const YCHAR * name,
                                 __u32 mode, __u32 uid, __u32 gid, __u32 rdev)
{
        return yaffs_MknodObject(YAFFS_OBJECT_TYPE_SPECIAL, parent, name, mode,
                                 uid, gid, NULL, NULL, rdev);
}

yaffs_Object *yaffs_MknodSymLink(yaffs_Object * parent, const YCHAR * name,
                                 __u32 mode, __u32 uid, __u32 gid,
                                 const YCHAR * alias)
{
        return yaffs_MknodObject(YAFFS_OBJECT_TYPE_SYMLINK, parent, name, mode,
                                 uid, gid, NULL, alias, 0);
}

/* yaffs_Link returns the object id of the equivalent object.*/
yaffs_Object *yaffs_Link(yaffs_Object * parent, const YCHAR * name,
                         yaffs_Object * equivalentObject)
{
        /* Get the real object in case we were fed a hard link as an equivalent object */
        equivalentObject = yaffs_GetEquivalentObject(equivalentObject);

        if (yaffs_MknodObject
            (YAFFS_OBJECT_TYPE_HARDLINK, parent, name, 0, 0, 0,
             equivalentObject, NULL, 0)) {
                return equivalentObject;
        } else {
                return NULL;
        }

}

static int yaffs_ChangeObjectName(yaffs_Object * obj, yaffs_Object * newDir,
                                  const YCHAR * newName, int force, int shadows)
{
        int unlinkOp;
        int deleteOp;

        yaffs_Object *existingTarget;

        if (newDir == NULL) {
                newDir = obj->parent;   /* use the old directory */
        }

        if (newDir->variantType != YAFFS_OBJECT_TYPE_DIRECTORY) {
                T(YAFFS_TRACE_ALWAYS,
                  (TSTR
                   ("tragendy: yaffs_ChangeObjectName: newDir is not a directory"
                    TENDSTR)));
                YBUG();
        }

        /* TODO: Do we need this different handling for YAFFS2 and YAFFS1?? */
        if (obj->myDev->isYaffs2) {
                unlinkOp = (newDir == obj->myDev->unlinkedDir);
        } else {
                unlinkOp = (newDir == obj->myDev->unlinkedDir
                            && obj->variantType == YAFFS_OBJECT_TYPE_FILE);
        }

        deleteOp = (newDir == obj->myDev->deletedDir);

        existingTarget = yaffs_FindObjectByName(newDir, newName);

        /* If the object is a file going into the unlinked directory,
         *   then it is OK to just stuff it in since duplicate names are allowed.
         *   else only proceed if the new name does not exist and if we're putting
         *   it into a directory.
         */
        if ((unlinkOp ||
             deleteOp ||
             force ||
             (shadows > 0) ||
             !existingTarget) &&
            newDir->variantType == YAFFS_OBJECT_TYPE_DIRECTORY) {
                yaffs_SetObjectName(obj, newName);
                obj->dirty = 1;

                yaffs_AddObjectToDirectory(newDir, obj);

                if (unlinkOp)
                        obj->unlinked = 1;

                /* If it is a deletion then we mark it as a shrink for gc purposes. */
                if (yaffs_UpdateObjectHeader(obj, newName, 0, deleteOp, shadows)>= 0)
                        return YAFFS_OK;
        }

        return YAFFS_FAIL;
}

int yaffs_RenameObject(yaffs_Object * oldDir, const YCHAR * oldName,
                       yaffs_Object * newDir, const YCHAR * newName)
{
        yaffs_Object *obj;
        yaffs_Object *existingTarget;
        int force = 0;

#ifdef CONFIG_YAFFS_CASE_INSENSITIVE
        /* Special case for case insemsitive systems (eg. WinCE).
         * While look-up is case insensitive, the name isn't.
         * Therefore we might want to change x.txt to X.txt
        */
        if (oldDir == newDir && yaffs_strcmp(oldName, newName) == 0) {
                force = 1;
        }
#endif

        obj = yaffs_FindObjectByName(oldDir, oldName);
        /* Check new name to long. */
        if (obj->variantType == YAFFS_OBJECT_TYPE_SYMLINK &&
            yaffs_strlen(newName) > YAFFS_MAX_ALIAS_LENGTH)
          /* ENAMETOOLONG */
          return YAFFS_FAIL;
        else if (obj->variantType != YAFFS_OBJECT_TYPE_SYMLINK &&
                 yaffs_strlen(newName) > YAFFS_MAX_NAME_LENGTH)
          /* ENAMETOOLONG */
          return YAFFS_FAIL;

        if (obj && obj->renameAllowed) {

                /* Now do the handling for an existing target, if there is one */

                existingTarget = yaffs_FindObjectByName(newDir, newName);
                if (existingTarget &&
                    existingTarget->variantType == YAFFS_OBJECT_TYPE_DIRECTORY &&
                    !list_empty(&existingTarget->variant.directoryVariant.children)) {
                        /* There is a target that is a non-empty directory, so we fail */
                        return YAFFS_FAIL;      /* EEXIST or ENOTEMPTY */
                } else if (existingTarget && existingTarget != obj) {
                        /* Nuke the target first, using shadowing,
                         * but only if it isn't the same object
                         */
                        yaffs_ChangeObjectName(obj, newDir, newName, force,
                                               existingTarget->objectId);
                        yaffs_UnlinkObject(existingTarget);
                }

                return yaffs_ChangeObjectName(obj, newDir, newName, 1, 0);
        }
        return YAFFS_FAIL;
}

/*------------------------- Block Management and Page Allocation ----------------*/

static int yaffs_InitialiseBlocks(yaffs_Device * dev)
{
        int nBlocks = dev->internalEndBlock - dev->internalStartBlock + 1;

        dev->blockInfo = NULL;
        dev->chunkBits = NULL;

        dev->allocationBlock = -1;      /* force it to get a new one */

        /* If the first allocation strategy fails, thry the alternate one */
        dev->blockInfo = YMALLOC(nBlocks * sizeof(yaffs_BlockInfo));
        if(!dev->blockInfo){
                dev->blockInfo = YMALLOC_ALT(nBlocks * sizeof(yaffs_BlockInfo));
                dev->blockInfoAlt = 1;
        }
        else
                dev->blockInfoAlt = 0;

        if(dev->blockInfo){

                /* Set up dynamic blockinfo stuff. */
                dev->chunkBitmapStride = (dev->nChunksPerBlock + 7) / 8; /* round up bytes */
                dev->chunkBits = YMALLOC(dev->chunkBitmapStride * nBlocks);
                if(!dev->chunkBits){
                        dev->chunkBits = YMALLOC_ALT(dev->chunkBitmapStride * nBlocks);
                        dev->chunkBitsAlt = 1;
                }
                else
                        dev->chunkBitsAlt = 0;
        }

        if (dev->blockInfo && dev->chunkBits) {
                memset(dev->blockInfo, 0, nBlocks * sizeof(yaffs_BlockInfo));
                memset(dev->chunkBits, 0, dev->chunkBitmapStride * nBlocks);
                return YAFFS_OK;
        }

        return YAFFS_FAIL;

}

static void yaffs_DeinitialiseBlocks(yaffs_Device * dev)
{
        if(dev->blockInfoAlt && dev->blockInfo)
                YFREE_ALT(dev->blockInfo);
        else if(dev->blockInfo)
                YFREE(dev->blockInfo);

        dev->blockInfoAlt = 0;

        dev->blockInfo = NULL;

        if(dev->chunkBitsAlt && dev->chunkBits)
                YFREE_ALT(dev->chunkBits);
        else if(dev->chunkBits)
                YFREE(dev->chunkBits);
        dev->chunkBitsAlt = 0;
        dev->chunkBits = NULL;
}

static int yaffs_BlockNotDisqualifiedFromGC(yaffs_Device * dev,
                                            yaffs_BlockInfo * bi)
{
        int i;
        __u32 seq;
        yaffs_BlockInfo *b;

        if (!dev->isYaffs2)
                return 1;       /* disqualification only applies to yaffs2. */

        if (!bi->hasShrinkHeader)
                return 1;       /* can gc */

        /* Find the oldest dirty sequence number if we don't know it and save it
         * so we don't have to keep recomputing it.
         */
        if (!dev->oldestDirtySequence) {
                seq = dev->sequenceNumber;

                for (i = dev->internalStartBlock; i <= dev->internalEndBlock;
                     i++) {
                        b = yaffs_GetBlockInfo(dev, i);
                        if (b->blockState == YAFFS_BLOCK_STATE_FULL &&
                            (b->pagesInUse - b->softDeletions) <
                            dev->nChunksPerBlock && b->sequenceNumber < seq) {
                                seq = b->sequenceNumber;
                        }
                }
                dev->oldestDirtySequence = seq;
        }

        /* Can't do gc of this block if there are any blocks older than this one that have
         * discarded pages.
         */
        return (bi->sequenceNumber <= dev->oldestDirtySequence);

}

/* FindDiretiestBlock is used to select the dirtiest block (or close enough)
 * for garbage collection.
 */

static int yaffs_FindBlockForGarbageCollection(yaffs_Device * dev,
                                               int aggressive)
{

        int b = dev->currentDirtyChecker;

        int i;
        int iterations;
        int dirtiest = -1;
        int pagesInUse = 0;
        int prioritised=0;
        yaffs_BlockInfo *bi;
        int pendingPrioritisedExist = 0;

        /* First let's see if we need to grab a prioritised block */
        if(dev->hasPendingPrioritisedGCs){
                for(i = dev->internalStartBlock; i < dev->internalEndBlock && !prioritised; i++){

                        bi = yaffs_GetBlockInfo(dev, i);
                        //yaffs_VerifyBlock(dev,bi,i);

                        if(bi->gcPrioritise) {
                                pendingPrioritisedExist = 1;
                                if(bi->blockState == YAFFS_BLOCK_STATE_FULL &&
                                   yaffs_BlockNotDisqualifiedFromGC(dev, bi)){
                                        pagesInUse = (bi->pagesInUse - bi->softDeletions);
                                        dirtiest = i;
                                        prioritised = 1;
                                        aggressive = 1; /* Fool the non-aggressive skip logiv below */
                                }
                        }
                }

                if(!pendingPrioritisedExist) /* None found, so we can clear this */
                        dev->hasPendingPrioritisedGCs = 0;
        }

        /* If we're doing aggressive GC then we are happy to take a less-dirty block, and
         * search harder.
         * else (we're doing a leasurely gc), then we only bother to do this if the
         * block has only a few pages in use.
         */

        dev->nonAggressiveSkip--;

        if (!aggressive && (dev->nonAggressiveSkip > 0)) {
                return -1;
        }

        if(!prioritised)
                pagesInUse =
                        (aggressive) ? dev->nChunksPerBlock : YAFFS_PASSIVE_GC_CHUNKS + 1;

        if (aggressive) {
                iterations =
                    dev->internalEndBlock - dev->internalStartBlock + 1;
        } else {
                iterations =
                    dev->internalEndBlock - dev->internalStartBlock + 1;
                iterations = iterations / 16;
                if (iterations > 200) {
                        iterations = 200;
                }
        }

        for (i = 0; i <= iterations && pagesInUse > 0 && !prioritised; i++) {
                b++;
                if (b < dev->internalStartBlock || b > dev->internalEndBlock) {
                        b = dev->internalStartBlock;
                }

                if (b < dev->internalStartBlock || b > dev->internalEndBlock) {
                        T(YAFFS_TRACE_ERROR,
                          (TSTR("**>> Block %d is not valid" TENDSTR), b));
                        YBUG();
                }

                bi = yaffs_GetBlockInfo(dev, b);

#if 0
                if (bi->blockState == YAFFS_BLOCK_STATE_CHECKPOINT) {
                        dirtiest = b;
                        pagesInUse = 0;
                }
                else
#endif

                if (bi->blockState == YAFFS_BLOCK_STATE_FULL &&
                       (bi->pagesInUse - bi->softDeletions) < pagesInUse &&
                        yaffs_BlockNotDisqualifiedFromGC(dev, bi)) {
                        dirtiest = b;
                        pagesInUse = (bi->pagesInUse - bi->softDeletions);
                }
        }

        dev->currentDirtyChecker = b;

        if (dirtiest > 0) {
                T(YAFFS_TRACE_GC,
                  (TSTR("GC Selected block %d with %d free, prioritised:%d" TENDSTR), dirtiest,
                   dev->nChunksPerBlock - pagesInUse,prioritised));
        }

        dev->oldestDirtySequence = 0;

        if (dirtiest > 0) {
                dev->nonAggressiveSkip = 4;
        }

        return dirtiest;
}

static void yaffs_BlockBecameDirty(yaffs_Device * dev, int blockNo)
{
        yaffs_BlockInfo *bi = yaffs_GetBlockInfo(dev, blockNo);

        int erasedOk = 0;

        /* If the block is still healthy erase it and mark as clean.
         * If the block has had a data failure, then retire it.
         */

        T(YAFFS_TRACE_GC | YAFFS_TRACE_ERASE,
                (TSTR("yaffs_BlockBecameDirty block %d state %d %s"TENDSTR),
                blockNo, bi->blockState, (bi->needsRetiring) ? "needs retiring" : ""));

        bi->blockState = YAFFS_BLOCK_STATE_DIRTY;

        if (!bi->needsRetiring) {
                yaffs_InvalidateCheckpoint(dev);
                erasedOk = yaffs_EraseBlockInNAND(dev, blockNo);
                if (!erasedOk) {
                        dev->nErasureFailures++;
                        T(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
                          (TSTR("**>> Erasure failed %d" TENDSTR), blockNo));
                }
        }

        if (erasedOk &&
            ((yaffs_traceMask & YAFFS_TRACE_ERASE) || !yaffs_SkipVerification(dev))) {
                int i;
                for (i = 0; i < dev->nChunksPerBlock; i++) {
                        if (!yaffs_CheckChunkErased
                            (dev, blockNo * dev->nChunksPerBlock + i)) {
                                T(YAFFS_TRACE_ERROR,
                                  (TSTR
                                   (">>Block %d erasure supposedly OK, but chunk %d not erased"
                                    TENDSTR), blockNo, i));
                        }
                }
        }

        if (erasedOk) {
                /* Clean it up... */
                bi->blockState = YAFFS_BLOCK_STATE_EMPTY;
                dev->nErasedBlocks++;
                bi->pagesInUse = 0;
                bi->softDeletions = 0;
                bi->hasShrinkHeader = 0;
                bi->skipErasedCheck = 1;  /* This is clean, so no need to check */
                bi->gcPrioritise = 0;
                yaffs_ClearChunkBits(dev, blockNo);

                T(YAFFS_TRACE_ERASE,
                  (TSTR("Erased block %d" TENDSTR), blockNo));
        } else {
                dev->nFreeChunks -= dev->nChunksPerBlock;       /* We lost a block of free space */

                yaffs_RetireBlock(dev, blockNo);
                T(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
                  (TSTR("**>> Block %d retired" TENDSTR), blockNo));
        }
}

static int yaffs_FindBlockForAllocation(yaffs_Device * dev)
{
        int i;

        yaffs_BlockInfo *bi;

        if (dev->nErasedBlocks < 1) {
                /* Hoosterman we've got a problem.
                 * Can't get space to gc
                 */
                T(YAFFS_TRACE_ERROR,
                  (TSTR("yaffs tragedy: no more eraased blocks" TENDSTR)));

                return -1;
        }

        /* Find an empty block. */

        for (i = dev->internalStartBlock; i <= dev->internalEndBlock; i++) {
                dev->allocationBlockFinder++;
                if (dev->allocationBlockFinder < dev->internalStartBlock
                    || dev->allocationBlockFinder > dev->internalEndBlock) {
                        dev->allocationBlockFinder = dev->internalStartBlock;
                }

                bi = yaffs_GetBlockInfo(dev, dev->allocationBlockFinder);

                if (bi->blockState == YAFFS_BLOCK_STATE_EMPTY) {
                        bi->blockState = YAFFS_BLOCK_STATE_ALLOCATING;
                        dev->sequenceNumber++;
                        bi->sequenceNumber = dev->sequenceNumber;
                        dev->nErasedBlocks--;
                        T(YAFFS_TRACE_ALLOCATE,
                          (TSTR("Allocated block %d, seq  %d, %d left" TENDSTR),
                           dev->allocationBlockFinder, dev->sequenceNumber,
                           dev->nErasedBlocks));
                        return dev->allocationBlockFinder;
                }
        }

        T(YAFFS_TRACE_ALWAYS,
          (TSTR
           ("yaffs tragedy: no more eraased blocks, but there should have been %d"
            TENDSTR), dev->nErasedBlocks));

        return -1;
}


// Check if there's space to allocate...
// Thinks.... do we need top make this ths same as yaffs_GetFreeChunks()?
static int yaffs_CheckSpaceForAllocation(yaffs_Device * dev)
{
        int reservedChunks;
        int reservedBlocks = dev->nReservedBlocks;
        int checkpointBlocks;

        checkpointBlocks =  dev->nCheckpointReservedBlocks - dev->blocksInCheckpoint;
        if(checkpointBlocks < 0)
                checkpointBlocks = 0;

        reservedChunks = ((reservedBlocks + checkpointBlocks) * dev->nChunksPerBlock);

        return (dev->nFreeChunks > reservedChunks);
}

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

        if (dev->allocationBlock < 0) {
                /* Get next block to allocate off */
                dev->allocationBlock = yaffs_FindBlockForAllocation(dev);
                dev->allocationPage = 0;
        }

        if (!useReserve && !yaffs_CheckSpaceForAllocation(dev)) {
                /* Not enough space to allocate unless we're allowed to use the reserve. */
                return -1;
        }

        if (dev->nErasedBlocks < dev->nReservedBlocks
            && dev->allocationPage == 0) {
                T(YAFFS_TRACE_ALLOCATE, (TSTR("Allocating reserve" TENDSTR)));
        }

        /* Next page please.... */
        if (dev->allocationBlock >= 0) {
                bi = yaffs_GetBlockInfo(dev, dev->allocationBlock);

                retVal = (dev->allocationBlock * dev->nChunksPerBlock) +
                    dev->allocationPage;
                bi->pagesInUse++;
                yaffs_SetChunkBit(dev, dev->allocationBlock,
                                  dev->allocationPage);

                dev->allocationPage++;

                dev->nFreeChunks--;

                /* If the block is full set the state to full */
                if (dev->allocationPage >= dev->nChunksPerBlock) {
                        bi->blockState = YAFFS_BLOCK_STATE_FULL;
                        dev->allocationBlock = -1;
                }

                if(blockUsedPtr)
                        *blockUsedPtr = bi;

                return retVal;
        }

        T(YAFFS_TRACE_ERROR,
          (TSTR("!!!!!!!!! Allocator out !!!!!!!!!!!!!!!!!" TENDSTR)));

        return -1;
}

static int yaffs_GetErasedChunks(yaffs_Device * dev)
{
        int n;

        n = dev->nErasedBlocks * dev->nChunksPerBlock;

        if (dev->allocationBlock > 0) {
                n += (dev->nChunksPerBlock - dev->allocationPage);
        }

        return n;

}

static int yaffs_GarbageCollectBlock(yaffs_Device * dev, int block)
{
        int oldChunk;
        int newChunk;
        int chunkInBlock;
        int markNAND;
        int retVal = YAFFS_OK;
        int cleanups = 0;
        int i;
        int isCheckpointBlock;
        int matchingChunk;

        int chunksBefore = yaffs_GetErasedChunks(dev);
        int chunksAfter;

        yaffs_ExtendedTags tags;

        yaffs_BlockInfo *bi = yaffs_GetBlockInfo(dev, block);

        yaffs_Object *object;

        isCheckpointBlock = (bi->blockState == YAFFS_BLOCK_STATE_CHECKPOINT);

        bi->blockState = YAFFS_BLOCK_STATE_COLLECTING;

        T(YAFFS_TRACE_TRACING,
          (TSTR("Collecting block %d, in use %d, shrink %d, " TENDSTR), block,
           bi->pagesInUse, bi->hasShrinkHeader));

        /*yaffs_VerifyFreeChunks(dev); */

        bi->hasShrinkHeader = 0;        /* clear the flag so that the block can erase */

        /* Take off the number of soft deleted entries because
         * they're going to get really deleted during GC.
         */
        dev->nFreeChunks -= bi->softDeletions;

        dev->isDoingGC = 1;

        if (isCheckpointBlock ||
            !yaffs_StillSomeChunkBits(dev, block)) {
                T(YAFFS_TRACE_TRACING,
                  (TSTR
                   ("Collecting block %d that has no chunks in use" TENDSTR),
                   block));
                yaffs_BlockBecameDirty(dev, block);
        } else {

                __u8 *buffer = yaffs_GetTempBuffer(dev, __LINE__);

                yaffs_VerifyBlock(dev,bi,block);

                for (chunkInBlock = 0, oldChunk = block * dev->nChunksPerBlock;
                     chunkInBlock < dev->nChunksPerBlock
                     && yaffs_StillSomeChunkBits(dev, block);
                     chunkInBlock++, oldChunk++) {
                        if (yaffs_CheckChunkBit(dev, block, chunkInBlock)) {

                                /* This page is in use and might need to be copied off */

                                markNAND = 1;

                                yaffs_InitialiseTags(&tags);

                                yaffs_ReadChunkWithTagsFromNAND(dev, oldChunk,
                                                                buffer, &tags);

                                object =
                                    yaffs_FindObjectByNumber(dev,
                                                             tags.objectId);

                                T(YAFFS_TRACE_GC_DETAIL,
                                  (TSTR
                                   ("Collecting page %d, %d %d %d " TENDSTR),
                                   chunkInBlock, tags.objectId, tags.chunkId,
                                   tags.byteCount));

                                if(object && !yaffs_SkipVerification(dev)){
                                        if(tags.chunkId == 0)
                                                matchingChunk = object->chunkId;
                                        else if(object->softDeleted)
                                                matchingChunk = oldChunk; /* Defeat the test */
                                        else
                                                matchingChunk = yaffs_FindChunkInFile(object,tags.chunkId,NULL);

                                        if(oldChunk != matchingChunk)
                                                T(YAFFS_TRACE_ERROR,
                                                  (TSTR("gc: page in gc mismatch: %d %d %d %d"TENDSTR),
                                                  oldChunk,matchingChunk,tags.objectId, tags.chunkId));

                                }

                                if (!object) {
                                        T(YAFFS_TRACE_ERROR,
                                          (TSTR

                                           ("page %d in gc has no object: %d %d %d "
                                            TENDSTR), oldChunk,
                                            tags.objectId, tags.chunkId, tags.byteCount));
                                }

                                if (object && object->deleted
                                    && tags.chunkId != 0) {
                                        /* Data chunk in a deleted file, throw it away
                                         * It's a soft deleted data chunk,
                                         * No need to copy this, just forget about it and
                                         * fix up the object.
                                         */

                                        object->nDataChunks--;

                                        if (object->nDataChunks <= 0) {
                                                /* remeber to clean up the object */
                                                dev->gcCleanupList[cleanups] =
                                                    tags.objectId;
                                                cleanups++;
                                        }
                                        markNAND = 0;
                                } else if (0
                                           /* Todo object && object->deleted && object->nDataChunks == 0 */
                                           ) {
                                        /* Deleted object header with no data chunks.
                                         * Can be discarded and the file deleted.
                                         */
                                        object->chunkId = 0;
                                        yaffs_FreeTnode(object->myDev,
                                                        object->variant.
                                                        fileVariant.top);
                                        object->variant.fileVariant.top = NULL;
                                        yaffs_DoGenericObjectDeletion(object);

                                } else if (object) {
                                        /* It's either a data chunk in a live file or
                                         * an ObjectHeader, so we're interested in it.
                                         * NB Need to keep the ObjectHeaders of deleted files
                                         * until the whole file has been deleted off
                                         */
                                        tags.serialNumber++;

                                        dev->nGCCopies++;

                                        if (tags.chunkId == 0) {
                                                /* It is an object Id,
                                                 * We need to nuke the shrinkheader flags first
                                                 * We no longer want the shrinkHeader flag since its work is done
                                                 * and if it is left in place it will mess up scanning.
                                                 * Also, clear out any shadowing stuff
                                                 */

                                                yaffs_ObjectHeader *oh;
                                                oh = (yaffs_ObjectHeader *)buffer;
                                                oh->isShrink = 0;
                                                oh->shadowsObject = -1;
                                                tags.extraShadows = 0;
                                                tags.extraIsShrinkHeader = 0;

                                                yaffs_VerifyObjectHeader(object,oh,&tags,1);
                                        }

                                        newChunk =
                                            yaffs_WriteNewChunkWithTagsToNAND(dev, buffer, &tags, 1);

                                        if (newChunk < 0) {
                                                retVal = YAFFS_FAIL;
                                        } else {

                                                /* Ok, now fix up the Tnodes etc. */

                                                if (tags.chunkId == 0) {
                                                        /* It's a header */
                                                        object->chunkId =  newChunk;
                                                        object->serial =   tags.serialNumber;
                                                } else {
                                                        /* It's a data chunk */
                                                        yaffs_PutChunkIntoFile
                                                            (object,
                                                             tags.chunkId,
                                                             newChunk, 0);
                                                }
                                        }
                                }

                                yaffs_DeleteChunk(dev, oldChunk, markNAND, __LINE__);

                        }
                }

                yaffs_ReleaseTempBuffer(dev, buffer, __LINE__);


                /* Do any required cleanups */
                for (i = 0; i < cleanups; i++) {
                        /* Time to delete the file too */
                        object =
                            yaffs_FindObjectByNumber(dev,
                                                     dev->gcCleanupList[i]);
                        if (object) {
                                yaffs_FreeTnode(dev,
                                                object->variant.fileVariant.
                                                top);
                                object->variant.fileVariant.top = NULL;
                                T(YAFFS_TRACE_GC,
                                  (TSTR
                                   ("yaffs: About to finally delete object %d"
                                    TENDSTR), object->objectId));
                                yaffs_DoGenericObjectDeletion(object);
                                object->myDev->nDeletedFiles--;
                        }

                }

        }

        yaffs_VerifyCollectedBlock(dev,bi,block);

        if (chunksBefore >= (chunksAfter = yaffs_GetErasedChunks(dev))) {
                T(YAFFS_TRACE_GC,
                  (TSTR
                   ("gc did not increase free chunks before %d after %d"
                    TENDSTR), chunksBefore, chunksAfter));
        }

        dev->isDoingGC = 0;

        return YAFFS_OK;
}

/* New garbage collector
 * If we're very low on erased blocks then we do aggressive garbage collection
 * otherwise we do "leasurely" garbage collection.
 * Aggressive gc looks further (whole array) and will accept less dirty blocks.
 * Passive gc only inspects smaller areas and will only accept more dirty blocks.
 *
 * The idea is to help clear out space in a more spread-out manner.
 * Dunno if it really does anything useful.
 */
static int yaffs_CheckGarbageCollection(yaffs_Device * dev)
{
        int block;
        int aggressive;
        int gcOk = YAFFS_OK;
        int maxTries = 0;

        int checkpointBlockAdjust;

        if (dev->isDoingGC) {
                /* Bail out so we don't get recursive gc */
                return YAFFS_OK;
        }

        /* This loop should pass the first time.
         * We'll only see looping here if the erase of the collected block fails.
         */

        do {
                maxTries++;

                checkpointBlockAdjust = (dev->nCheckpointReservedBlocks - dev->blocksInCheckpoint);
                if(checkpointBlockAdjust < 0)
                        checkpointBlockAdjust = 0;

                if (dev->nErasedBlocks < (dev->nReservedBlocks + checkpointBlockAdjust + 2)) {
                        /* We need a block soon...*/
                        aggressive = 1;
                } else {
                        /* We're in no hurry */
                        aggressive = 0;
                }

                block = yaffs_FindBlockForGarbageCollection(dev, aggressive);

                if (block > 0) {
                        dev->garbageCollections++;
                        if (!aggressive) {
                                dev->passiveGarbageCollections++;
                        }

                        T(YAFFS_TRACE_GC,
                          (TSTR
                           ("yaffs: GC erasedBlocks %d aggressive %d" TENDSTR),
                           dev->nErasedBlocks, aggressive));

                        gcOk = yaffs_GarbageCollectBlock(dev, block);
                }

                if (dev->nErasedBlocks < (dev->nReservedBlocks) && block > 0) {
                        T(YAFFS_TRACE_GC,
                          (TSTR
                           ("yaffs: GC !!!no reclaim!!! erasedBlocks %d after try %d block %d"
                            TENDSTR), dev->nErasedBlocks, maxTries, block));
                }
        } while ((dev->nErasedBlocks < dev->nReservedBlocks) && (block > 0)
                 && (maxTries < 2));

        return aggressive ? gcOk : YAFFS_OK;
}

/*-------------------------  TAGS --------------------------------*/

static int yaffs_TagsMatch(const yaffs_ExtendedTags * tags, int objectId,
                           int chunkInObject)
{
        return (tags->chunkId == chunkInObject &&
                tags->objectId == objectId && !tags->chunkDeleted) ? 1 : 0;

}


/*-------------------- Data file manipulation -----------------*/

static int yaffs_FindChunkInFile(yaffs_Object * in, int chunkInInode,
                                 yaffs_ExtendedTags * tags)
{
        /*Get the Tnode, then get the level 0 offset chunk offset */
        yaffs_Tnode *tn;
        int theChunk = -1;
        yaffs_ExtendedTags localTags;
        int retVal = -1;

        yaffs_Device *dev = in->myDev;

        if (!tags) {
                /* Passed a NULL, so use our own tags space */
                tags = &localTags;
        }

        tn = yaffs_FindLevel0Tnode(dev, &in->variant.fileVariant, chunkInInode);

        if (tn) {
                theChunk = yaffs_GetChunkGroupBase(dev,tn,chunkInInode);

                retVal =
                    yaffs_FindChunkInGroup(dev, theChunk, tags, in->objectId,
                                           chunkInInode);
        }
        return retVal;
}

static int yaffs_FindAndDeleteChunkInFile(yaffs_Object * in, int chunkInInode,
                                          yaffs_ExtendedTags * tags)
{
        /* Get the Tnode, then get the level 0 offset chunk offset */
        yaffs_Tnode *tn;
        int theChunk = -1;
        yaffs_ExtendedTags localTags;

        yaffs_Device *dev = in->myDev;
        int retVal = -1;

        if (!tags) {
                /* Passed a NULL, so use our own tags space */
                tags = &localTags;
        }

        tn = yaffs_FindLevel0Tnode(dev, &in->variant.fileVariant, chunkInInode);

        if (tn) {

                theChunk = yaffs_GetChunkGroupBase(dev,tn,chunkInInode);

                retVal =
                    yaffs_FindChunkInGroup(dev, theChunk, tags, in->objectId,
                                           chunkInInode);

                /* Delete the entry in the filestructure (if found) */
                if (retVal != -1) {
                        yaffs_PutLevel0Tnode(dev,tn,chunkInInode,0);
                }
        } else {
                /*T(("No level 0 found for %d\n", chunkInInode)); */
        }

        if (retVal == -1) {
                /* T(("Could not find %d to delete\n",chunkInInode)); */
        }
        return retVal;
}

#ifdef YAFFS_PARANOID

static int yaffs_CheckFileSanity(yaffs_Object * in)
{
        int chunk;
        int nChunks;
        int fSize;
        int failed = 0;
        int objId;
        yaffs_Tnode *tn;
        yaffs_Tags localTags;
        yaffs_Tags *tags = &localTags;
        int theChunk;
        int chunkDeleted;

        if (in->variantType != YAFFS_OBJECT_TYPE_FILE) {
                /* T(("Object not a file\n")); */
                return YAFFS_FAIL;
        }

        objId = in->objectId;
        fSize = in->variant.fileVariant.fileSize;
        nChunks =
            (fSize + in->myDev->nDataBytesPerChunk - 1) / in->myDev->nDataBytesPerChunk;

        for (chunk = 1; chunk <= nChunks; chunk++) {
                tn = yaffs_FindLevel0Tnode(in->myDev, &in->variant.fileVariant,
                                           chunk);

                if (tn) {

                        theChunk = yaffs_GetChunkGroupBase(dev,tn,chunk);

                        if (yaffs_CheckChunkBits
                            (dev, theChunk / dev->nChunksPerBlock,
                             theChunk % dev->nChunksPerBlock)) {

                                yaffs_ReadChunkTagsFromNAND(in->myDev, theChunk,
                                                            tags,
                                                            &chunkDeleted);
                                if (yaffs_TagsMatch
                                    (tags, in->objectId, chunk, chunkDeleted)) {
                                        /* found it; */

                                }
                        } else {

                                failed = 1;
                        }

                } else {
                        /* T(("No level 0 found for %d\n", chunk)); */
                }
        }

        return failed ? YAFFS_FAIL : YAFFS_OK;
}

#endif

static int yaffs_PutChunkIntoFile(yaffs_Object * in, int chunkInInode,
                                  int chunkInNAND, int inScan)
{
        /* NB inScan is zero unless scanning.
         * For forward scanning, inScan is > 0;
         * for backward scanning inScan is < 0
         */

        yaffs_Tnode *tn;
        yaffs_Device *dev = in->myDev;
        int existingChunk;
        yaffs_ExtendedTags existingTags;
        yaffs_ExtendedTags newTags;
        unsigned existingSerial, newSerial;

        if (in->variantType != YAFFS_OBJECT_TYPE_FILE) {
                /* Just ignore an attempt at putting a chunk into a non-file during scanning
                 * If it is not during Scanning then something went wrong!
                 */
                if (!inScan) {
                        T(YAFFS_TRACE_ERROR,
                          (TSTR
                           ("yaffs tragedy:attempt to put data chunk into a non-file"
                            TENDSTR)));
                        YBUG();
                }

                yaffs_DeleteChunk(dev, chunkInNAND, 1, __LINE__);
                return YAFFS_OK;
        }

        tn = yaffs_AddOrFindLevel0Tnode(dev,
                                        &in->variant.fileVariant,
                                        chunkInInode,
                                        NULL);
        if (!tn) {
                return YAFFS_FAIL;
        }

        existingChunk = yaffs_GetChunkGroupBase(dev,tn,chunkInInode);

        if (inScan != 0) {
                /* If we're scanning then we need to test for duplicates
                 * NB This does not need to be efficient since it should only ever
                 * happen when the power fails during a write, then only one
                 * chunk should ever be affected.
                 *
                 * Correction for YAFFS2: This could happen quite a lot and we need to think about efficiency! TODO
                 * Update: For backward scanning we don't need to re-read tags so this is quite cheap.
                 */

                if (existingChunk != 0) {
                        /* NB Right now existing chunk will not be real chunkId if the device >= 32MB
                         *    thus we have to do a FindChunkInFile to get the real chunk id.
                         *
                         * We have a duplicate now we need to decide which one to use:
                         *
                         * Backwards scanning YAFFS2: The old one is what we use, dump the new one.
                         * Forward scanning YAFFS2: The new one is what we use, dump the old one.
                         * YAFFS1: Get both sets of tags and compare serial numbers.
                         */

                        if (inScan > 0) {
                                /* Only do this for forward scanning */
                                yaffs_ReadChunkWithTagsFromNAND(dev,
                                                                chunkInNAND,
                                                                NULL, &newTags);

                                /* Do a proper find */
                                existingChunk =
                                    yaffs_FindChunkInFile(in, chunkInInode,
                                                          &existingTags);
                        }

                        if (existingChunk <= 0) {
                                /*Hoosterman - how did this happen? */

                                T(YAFFS_TRACE_ERROR,
                                  (TSTR
                                   ("yaffs tragedy: existing chunk < 0 in scan"
                                    TENDSTR)));

                        }

                        /* NB The deleted flags should be false, otherwise the chunks will
                         * not be loaded during a scan
                         */

                        newSerial = newTags.serialNumber;
                        existingSerial = existingTags.serialNumber;

                        if ((inScan > 0) &&
                            (in->myDev->isYaffs2 ||
                             existingChunk <= 0 ||
                             ((existingSerial + 1) & 3) == newSerial)) {
                                /* Forward scanning.
                                 * Use new
                                 * Delete the old one and drop through to update the tnode
                                 */
                                yaffs_DeleteChunk(dev, existingChunk, 1,
                                                  __LINE__);
                        } else {
                                /* Backward scanning or we want to use the existing one
                                 * Use existing.
                                 * Delete the new one and return early so that the tnode isn't changed
                                 */
                                yaffs_DeleteChunk(dev, chunkInNAND, 1,
                                                  __LINE__);
                                return YAFFS_OK;
                        }
                }

        }

        if (existingChunk == 0) {
                in->nDataChunks++;
        }

        yaffs_PutLevel0Tnode(dev,tn,chunkInInode,chunkInNAND);

        return YAFFS_OK;
}

static int yaffs_ReadChunkDataFromObject(yaffs_Object * in, int chunkInInode,
                                         __u8 * buffer)
{
        int chunkInNAND = yaffs_FindChunkInFile(in, chunkInInode, NULL);

        if (chunkInNAND >= 0) {
                return yaffs_ReadChunkWithTagsFromNAND(in->myDev, chunkInNAND,
                                                       buffer,NULL);
        } else {
                T(YAFFS_TRACE_NANDACCESS,
                  (TSTR("Chunk %d not found zero instead" TENDSTR),
                   chunkInNAND));
                /* get sane (zero) data if you read a hole */
                memset(buffer, 0, in->myDev->nDataBytesPerChunk);
                return 0;
        }

}

void yaffs_DeleteChunk(yaffs_Device * dev, int chunkId, int markNAND, int lyn)
{
        int block;
        int page;
        yaffs_ExtendedTags tags;
        yaffs_BlockInfo *bi;

        if (chunkId <= 0)
                return;


        dev->nDeletions++;
        block = chunkId / dev->nChunksPerBlock;
        page = chunkId % dev->nChunksPerBlock;


        if(!yaffs_CheckChunkBit(dev,block,page))
                T(YAFFS_TRACE_VERIFY,
                        (TSTR("Deleting invalid chunk %d"TENDSTR),
                         chunkId));

        bi = yaffs_GetBlockInfo(dev, block);

        T(YAFFS_TRACE_DELETION,
          (TSTR("line %d delete of chunk %d" TENDSTR), lyn, chunkId));

        if (markNAND &&
            bi->blockState != YAFFS_BLOCK_STATE_COLLECTING && !dev->isYaffs2) {

                yaffs_InitialiseTags(&tags);

                tags.chunkDeleted = 1;

                yaffs_WriteChunkWithTagsToNAND(dev, chunkId, NULL, &tags);
                yaffs_HandleUpdateChunk(dev, chunkId, &tags);
        } else {
                dev->nUnmarkedDeletions++;
        }

        /* Pull out of the management area.
         * If the whole block became dirty, this will kick off an erasure.
         */
        if (bi->blockState == YAFFS_BLOCK_STATE_ALLOCATING ||
            bi->blockState == YAFFS_BLOCK_STATE_FULL ||
            bi->blockState == YAFFS_BLOCK_STATE_NEEDS_SCANNING ||
            bi->blockState == YAFFS_BLOCK_STATE_COLLECTING) {
                dev->nFreeChunks++;

                yaffs_ClearChunkBit(dev, block, page);

                bi->pagesInUse--;

                if (bi->pagesInUse == 0 &&
                    !bi->hasShrinkHeader &&
                    bi->blockState != YAFFS_BLOCK_STATE_ALLOCATING &&
                    bi->blockState != YAFFS_BLOCK_STATE_NEEDS_SCANNING) {
                        yaffs_BlockBecameDirty(dev, block);
                }

        } else {
                /* T(("Bad news deleting chunk %d\n",chunkId)); */
        }

}

static int yaffs_WriteChunkDataToObject(yaffs_Object * in, int chunkInInode,
                                        const __u8 * buffer, int nBytes,
                                        int useReserve)
{
        /* Find old chunk Need to do this to get serial number
         * Write new one and patch into tree.
         * Invalidate old tags.
         */

        int prevChunkId;
        yaffs_ExtendedTags prevTags;

        int newChunkId;
        yaffs_ExtendedTags newTags;

        yaffs_Device *dev = in->myDev;

        yaffs_CheckGarbageCollection(dev);

        /* Get the previous chunk at this location in the file if it exists */
        prevChunkId = yaffs_FindChunkInFile(in, chunkInInode, &prevTags);

        /* Set up new tags */
        yaffs_InitialiseTags(&newTags);

        newTags.chunkId = chunkInInode;
        newTags.objectId = in->objectId;
        newTags.serialNumber =
            (prevChunkId >= 0) ? prevTags.serialNumber + 1 : 1;
        newTags.byteCount = nBytes;

        newChunkId =
            yaffs_WriteNewChunkWithTagsToNAND(dev, buffer, &newTags,
                                              useReserve);

        if (newChunkId >= 0) {
                yaffs_PutChunkIntoFile(in, chunkInInode, newChunkId, 0);

                if (prevChunkId >= 0) {
                        yaffs_DeleteChunk(dev, prevChunkId, 1, __LINE__);

                }

                yaffs_CheckFileSanity(in);
        }
        return newChunkId;

}

/* UpdateObjectHeader updates the header on NAND for an object.
 * If name is not NULL, then that new name is used.
 */
int yaffs_UpdateObjectHeader(yaffs_Object * in, const YCHAR * name, int force,
                             int isShrink, int shadows)
{

        yaffs_BlockInfo *bi;

        yaffs_Device *dev = in->myDev;

        int prevChunkId;
        int retVal = 0;
        int result = 0;

        int newChunkId;
        yaffs_ExtendedTags newTags;
        yaffs_ExtendedTags oldTags;

        __u8 *buffer = NULL;
        YCHAR oldName[YAFFS_MAX_NAME_LENGTH + 1];

        yaffs_ObjectHeader *oh = NULL;

        yaffs_strcpy(oldName,"silly old name");

        if (!in->fake || force) {

                yaffs_CheckGarbageCollection(dev);
                yaffs_CheckObjectDetailsLoaded(in);

                buffer = yaffs_GetTempBuffer(in->myDev, __LINE__);
                oh = (yaffs_ObjectHeader *) buffer;

                prevChunkId = in->chunkId;

                if (prevChunkId >= 0) {
                        result = yaffs_ReadChunkWithTagsFromNAND(dev, prevChunkId,
                                                        buffer, &oldTags);

                        yaffs_VerifyObjectHeader(in,oh,&oldTags,0);

                        memcpy(oldName, oh->name, sizeof(oh->name));
                }

                memset(buffer, 0xFF, dev->nDataBytesPerChunk);

                oh->type = in->variantType;
                oh->yst_mode = in->yst_mode;
                oh->shadowsObject = shadows;

#ifdef CONFIG_YAFFS_WINCE
                oh->win_atime[0] = in->win_atime[0];
                oh->win_ctime[0] = in->win_ctime[0];
                oh->win_mtime[0] = in->win_mtime[0];
                oh->win_atime[1] = in->win_atime[1];
                oh->win_ctime[1] = in->win_ctime[1];
                oh->win_mtime[1] = in->win_mtime[1];
#else
                oh->yst_uid = in->yst_uid;
                oh->yst_gid = in->yst_gid;
                oh->yst_atime = in->yst_atime;
                oh->yst_mtime = in->yst_mtime;
                oh->yst_ctime = in->yst_ctime;
                oh->yst_rdev = in->yst_rdev;
#endif
                if (in->parent) {
                        oh->parentObjectId = in->parent->objectId;
                } else {
                        oh->parentObjectId = 0;
                }

                if (name && *name) {
                        memset(oh->name, 0, sizeof(oh->name));
                        yaffs_strncpy(oh->name, name, YAFFS_MAX_NAME_LENGTH);
                } else if (prevChunkId>=0) {
                        memcpy(oh->name, oldName, sizeof(oh->name));
                } else {
                        memset(oh->name, 0, sizeof(oh->name));
                }

                oh->isShrink = isShrink;

                switch (in->variantType) {
                case YAFFS_OBJECT_TYPE_UNKNOWN:
                        /* Should not happen */
                        break;
                case YAFFS_OBJECT_TYPE_FILE:
                        oh->fileSize =
                            (oh->parentObjectId == YAFFS_OBJECTID_DELETED
                             || oh->parentObjectId ==
                             YAFFS_OBJECTID_UNLINKED) ? 0 : in->variant.
                            fileVariant.fileSize;
                        break;
                case YAFFS_OBJECT_TYPE_HARDLINK:
                        oh->equivalentObjectId =
                            in->variant.hardLinkVariant.equivalentObjectId;
                        break;
                case YAFFS_OBJECT_TYPE_SPECIAL:
                        /* Do nothing */
                        break;
                case YAFFS_OBJECT_TYPE_DIRECTORY:
                        /* Do nothing */
                        break;
                case YAFFS_OBJECT_TYPE_SYMLINK:
                        yaffs_strncpy(oh->alias,
                                      in->variant.symLinkVariant.alias,
                                      YAFFS_MAX_ALIAS_LENGTH);
                        oh->alias[YAFFS_MAX_ALIAS_LENGTH] = 0;
                        break;
                }

                /* Tags */
                yaffs_InitialiseTags(&newTags);
                in->serial++;
                newTags.chunkId = 0;
                newTags.objectId = in->objectId;
                newTags.serialNumber = in->serial;

                /* Add extra info for file header */

                newTags.extraHeaderInfoAvailable = 1;
                newTags.extraParentObjectId = oh->parentObjectId;
                newTags.extraFileLength = oh->fileSize;
                newTags.extraIsShrinkHeader = oh->isShrink;
                newTags.extraEquivalentObjectId = oh->equivalentObjectId;
                newTags.extraShadows = (oh->shadowsObject > 0) ? 1 : 0;
                newTags.extraObjectType = in->variantType;

                yaffs_VerifyObjectHeader(in,oh,&newTags,1);

                /* Create new chunk in NAND */
                newChunkId =
                    yaffs_WriteNewChunkWithTagsToNAND(dev, buffer, &newTags,
                                                      (prevChunkId >= 0) ? 1 : 0);

                if (newChunkId >= 0) {

                        in->chunkId = newChunkId;

                        if (prevChunkId >= 0) {
                                yaffs_DeleteChunk(dev, prevChunkId, 1,
                                                  __LINE__);
                        }

                        if(!yaffs_ObjectHasCachedWriteData(in))
                                in->dirty = 0;

                        /* If this was a shrink, then mark the block that the chunk lives on */
                        if (isShrink) {
                                bi = yaffs_GetBlockInfo(in->myDev,
                                                        newChunkId /in->myDev-> nChunksPerBlock);
                                bi->hasShrinkHeader = 1;
                        }

                }

                retVal = newChunkId;

        }

        if (buffer)
                yaffs_ReleaseTempBuffer(dev, buffer, __LINE__);

        return retVal;
}

/*------------------------ Short Operations Cache ----------------------------------------
 *   In many situations where there is no high level buffering (eg WinCE) a lot of
 *   reads might be short sequential reads, and a lot of writes may be short
 *   sequential writes. eg. scanning/writing a jpeg file.
 *   In these cases, a short read/write cache can provide a huge perfomance benefit
 *   with dumb-as-a-rock code.
 *   In Linux, the page cache provides read buffering aand the short op cache provides write
 *   buffering.
 *
 *   There are a limited number (~10) of cache chunks per device so that we don't
 *   need a very intelligent search.
 */

static int yaffs_ObjectHasCachedWriteData(yaffs_Object *obj)
{
        yaffs_Device *dev = obj->myDev;
        int i;
        yaffs_ChunkCache *cache;
        int nCaches = obj->myDev->nShortOpCaches;

        for(i = 0; i < nCaches; i++){
                cache = &dev->srCache[i];
                if (cache->object == obj &&
                    cache->dirty)
                        return 1;
        }

        return 0;
}


static void yaffs_FlushFilesChunkCache(yaffs_Object * obj)
{
        yaffs_Device *dev = obj->myDev;
        int lowest = -99;       /* Stop compiler whining. */
        int i;
        yaffs_ChunkCache *cache;
        int chunkWritten = 0;
        int nCaches = obj->myDev->nShortOpCaches;

        if (nCaches > 0) {
                do {
                        cache = NULL;

                        /* Find the dirty cache for this object with the lowest chunk id. */
                        for (i = 0; i < nCaches; i++) {
                                if (dev->srCache[i].object == obj &&
                                    dev->srCache[i].dirty) {
                                        if (!cache
                                            || dev->srCache[i].chunkId <
                                            lowest) {
                                                cache = &dev->srCache[i];
                                                lowest = cache->chunkId;
                                        }
                                }
                        }

                        if (cache && !cache->locked) {
                                /* Write it out and free it up */

                                chunkWritten =
                                    yaffs_WriteChunkDataToObject(cache->object,
                                                                 cache->chunkId,
                                                                 cache->data,
                                                                 cache->nBytes,
                                                                 1);
                                cache->dirty = 0;
                                cache->object = NULL;
                        }

                } while (cache && chunkWritten > 0);

                if (cache) {
                        /* Hoosterman, disk full while writing cache out. */
                        T(YAFFS_TRACE_ERROR,
                          (TSTR("yaffs tragedy: no space during cache write" TENDSTR)));

                }
        }

}

/*yaffs_FlushEntireDeviceCache(dev)
 *
 *
 */

void yaffs_FlushEntireDeviceCache(yaffs_Device *dev)
{
        yaffs_Object *obj;
        int nCaches = dev->nShortOpCaches;
        int i;

        /* Find a dirty object in the cache and flush it...
         * until there are no further dirty objects.
         */
        do {
                obj = NULL;
                for( i = 0; i < nCaches && !obj; i++) {
                        if (dev->srCache[i].object &&
                            dev->srCache[i].dirty)
                                obj = dev->srCache[i].object;

                }
                if(obj)
                        yaffs_FlushFilesChunkCache(obj);

        } while(obj);

}


/* Grab us a cache chunk for use.
 * First look for an empty one.
 * Then look for the least recently used non-dirty one.
 * Then look for the least recently used dirty one...., flush and look again.
 */
static yaffs_ChunkCache *yaffs_GrabChunkCacheWorker(yaffs_Device * dev)
{
        int i;
        int usage;
        int theOne;

        if (dev->nShortOpCaches > 0) {
                for (i = 0; i < dev->nShortOpCaches; i++) {
                        if (!dev->srCache[i].object)
                                return &dev->srCache[i];
                }

                return NULL;

                theOne = -1;
                usage = 0;      /* just to stop the compiler grizzling */

                for (i = 0; i < dev->nShortOpCaches; i++) {
                        if (!dev->srCache[i].dirty &&
                            ((dev->srCache[i].lastUse < usage && theOne >= 0) ||
                             theOne < 0)) {
                                usage = dev->srCache[i].lastUse;
                                theOne = i;
                        }
                }


                return theOne >= 0 ? &dev->srCache[theOne] : NULL;
        } else {
                return NULL;
        }

}

static yaffs_ChunkCache *yaffs_GrabChunkCache(yaffs_Device * dev)
{
        yaffs_ChunkCache *cache;
        yaffs_Object *theObj;
        int usage;
        int i;
        int pushout;

        if (dev->nShortOpCaches > 0) {
                /* Try find a non-dirty one... */

                cache = yaffs_GrabChunkCacheWorker(dev);

                if (!cache) {
                        /* They were all dirty, find the last recently used object and flush
                         * its cache, then  find again.
                         * NB what's here is not very accurate, we actually flush the object
                         * the last recently used page.
                         */

                        /* With locking we can't assume we can use entry zero */

                        theObj = NULL;
                        usage = -1;
                        cache = NULL;
                        pushout = -1;

                        for (i = 0; i < dev->nShortOpCaches; i++) {
                                if (dev->srCache[i].object &&
                                    !dev->srCache[i].locked &&
                                    (dev->srCache[i].lastUse < usage || !cache))
                                {
                                        usage = dev->srCache[i].lastUse;
                                        theObj = dev->srCache[i].object;
                                        cache = &dev->srCache[i];
                                        pushout = i;
                                }
                        }

                        if (!cache || cache->dirty) {
                                /* Flush and try again */
                                yaffs_FlushFilesChunkCache(theObj);
                                cache = yaffs_GrabChunkCacheWorker(dev);
                        }

                }
                return cache;
        } else
                return NULL;

}

/* Find a cached chunk */
static yaffs_ChunkCache *yaffs_FindChunkCache(const yaffs_Object * obj,
                                              int chunkId)
{
        yaffs_Device *dev = obj->myDev;
        int i;
        if (dev->nShortOpCaches > 0) {
                for (i = 0; i < dev->nShortOpCaches; i++) {
                        if (dev->srCache[i].object == obj &&
                            dev->srCache[i].chunkId == chunkId) {
                                dev->cacheHits++;

                                return &dev->srCache[i];
                        }
                }
        }
        return NULL;
}

/* Mark the chunk for the least recently used algorithym */
static void yaffs_UseChunkCache(yaffs_Device * dev, yaffs_ChunkCache * cache,
                                int isAWrite)
{

        if (dev->nShortOpCaches > 0) {
                if (dev->srLastUse < 0 || dev->srLastUse > 100000000) {
                        /* Reset the cache usages */
                        int i;
                        for (i = 1; i < dev->nShortOpCaches; i++) {
                                dev->srCache[i].lastUse = 0;
                        }
                        dev->srLastUse = 0;