Checkpointing changes
[yaffs2.git] / yaffs_guts.c
index e8873e1debfd176641816a23490676e9eafddbec..bc4e9b9846cf31dfb7b93e6387e1c13b9d658b14 100644 (file)
@@ -13,7 +13,7 @@
  */
 
 const char *yaffs_guts_c_version =
-    "$Id: yaffs_guts.c,v 1.31 2006-03-08 07:59:20 charles Exp $";
+    "$Id: yaffs_guts.c,v 1.32 2006-05-08 10:13:34 charles Exp $";
 
 #include "yportenv.h"
 
@@ -22,6 +22,12 @@ const char *yaffs_guts_c_version =
 #include "yaffs_tagsvalidity.h"
 
 #include "yaffs_tagscompat.h"
+#include "yaffs_nand.h"
+
+#include "yaffs_checkptrw.h"
+
+#include "yaffs_nand.h"
+
 
 #ifdef CONFIG_YAFFS_WINCE
 void yfsd_LockYAFFS(BOOL fsLockOnly);
@@ -32,21 +38,7 @@ void yfsd_UnlockYAFFS(BOOL fsLockOnly);
 
 #include "yaffs_ecc.h"
 
-/* NAND access */
-
-static Y_INLINE int yaffs_ReadChunkWithTagsFromNAND(yaffs_Device * dev,
-                                                   int chunkInNAND,
-                                                   __u8 * buffer,
-                                                   yaffs_ExtendedTags * tags);
-static Y_INLINE int yaffs_WriteChunkWithTagsToNAND(yaffs_Device * dev,
-                                                  int chunkInNAND,
-                                                  const __u8 * data,
-                                                  yaffs_ExtendedTags * tags);
-static Y_INLINE int yaffs_MarkBlockBad(yaffs_Device * dev, int blockNo);
-static Y_INLINE int yaffs_QueryInitialBlockState(yaffs_Device * dev,
-                                                int blockNo,
-                                                yaffs_BlockState * state,
-                                                unsigned *sequenceNumber);
+
 /* Robustification (if it ever comes about...) */
 static void yaffs_RetireBlock(yaffs_Device * dev, int blockInNAND);
 static void yaffs_HandleWriteChunkError(yaffs_Device * dev, int chunkInNAND);
@@ -59,6 +51,8 @@ static void yaffs_HandleUpdateChunk(yaffs_Device * dev, int chunkInNAND,
 /* Other local prototypes */
 static int yaffs_UnlinkObject( 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,
@@ -108,110 +102,7 @@ static int yaffs_CheckFileSanity(yaffs_Object * in);
 static void yaffs_InvalidateWholeChunkCache(yaffs_Object * in);
 static void yaffs_InvalidateChunkCache(yaffs_Object * object, int chunkId);
 
-
-/*
- *   Start of real code.
- */
-
-/*
- * NAND access layer
- */
-
-
-static int yaffs_ReadChunkWithTagsFromNAND(yaffs_Device * dev, int chunkInNAND,
-                                          __u8 * buffer,
-                                          yaffs_ExtendedTags * tags)
-{
-       chunkInNAND -= dev->chunkOffset;
-
-       if (dev->readChunkWithTagsFromNAND)
-               return dev->readChunkWithTagsFromNAND(dev, chunkInNAND, buffer,
-                                                     tags);
-       else
-               return yaffs_TagsCompatabilityReadChunkWithTagsFromNAND(dev,
-                                                                       chunkInNAND,
-                                                                       buffer,
-                                                                       tags);
-}
-
-static Y_INLINE int yaffs_WriteChunkWithTagsToNAND(yaffs_Device * dev,
-                                                  int chunkInNAND,
-                                                  const __u8 * buffer,
-                                                  yaffs_ExtendedTags * tags)
-{
-       chunkInNAND -= dev->chunkOffset;
-
-       if (tags) {
-               tags->sequenceNumber = dev->sequenceNumber;
-               tags->chunkUsed = 1;
-               if (!yaffs_ValidateTags(tags)) {
-                       T(YAFFS_TRACE_ERROR,
-                         (TSTR("Writing uninitialised tags" TENDSTR)));
-                       YBUG();
-               }
-               T(YAFFS_TRACE_WRITE,
-                 (TSTR("Writing chunk %d tags %d %d" TENDSTR), chunkInNAND,
-                  tags->objectId, tags->chunkId));
-       } else {
-               T(YAFFS_TRACE_ERROR, (TSTR("Writing with no tags" TENDSTR)));
-               YBUG();
-       }
-
-       if (dev->writeChunkWithTagsToNAND)
-               return dev->writeChunkWithTagsToNAND(dev, chunkInNAND, buffer,
-                                                    tags);
-       else
-               return yaffs_TagsCompatabilityWriteChunkWithTagsToNAND(dev,
-                                                                      chunkInNAND,
-                                                                      buffer,
-                                                                      tags);
-}
-
-static Y_INLINE int yaffs_MarkBlockBad(yaffs_Device * dev, int blockNo)
-{
-       blockNo -= dev->blockOffset;
-
-       if (dev->markNANDBlockBad)
-               return dev->markNANDBlockBad(dev, blockNo);
-       else
-               return yaffs_TagsCompatabilityMarkNANDBlockBad(dev, blockNo);
-}
-static Y_INLINE int yaffs_QueryInitialBlockState(yaffs_Device * dev,
-                                                int blockNo,
-                                                yaffs_BlockState * state,
-                                                unsigned *sequenceNumber)
-{
-       blockNo -= dev->blockOffset;
-
-       if (dev->queryNANDBlock)
-               return dev->queryNANDBlock(dev, blockNo, state, sequenceNumber);
-       else
-               return yaffs_TagsCompatabilityQueryNANDBlock(dev, blockNo,
-                                                            state,
-                                                            sequenceNumber);
-}
-
-static int yaffs_EraseBlockInNAND(struct yaffs_DeviceStruct *dev,
-                                 int blockInNAND)
-{
-       int result;
-
-       blockInNAND -= dev->blockOffset;
-
-       dev->nBlockErasures++;
-       result = dev->eraseBlockInNAND(dev, blockInNAND);
-
-       /* If at first we don't succeed, try again *once*.*/
-       if (!result)
-               result = dev->eraseBlockInNAND(dev, blockInNAND);       
-       return result;
-}
-
-static int yaffs_InitialiseNAND(struct yaffs_DeviceStruct *dev)
-{
-       return dev->initialiseNAND(dev);
-}
+static void yaffs_InvalidateCheckpoint(yaffs_Device *dev);
 
 /* 
  * Temporary buffer manipulations.
@@ -400,6 +291,8 @@ static int yaffs_WriteNewChunkWithTagsToNAND(struct yaffs_DeviceStruct *dev,
 
        int writeOk = 1;
        int attempts = 0;
+       
+       yaffs_InvalidateCheckpoint(dev);
 
        do {
                chunk = yaffs_AllocateChunk(dev, useReserve);
@@ -454,6 +347,8 @@ static int yaffs_WriteNewChunkWithTagsToNAND(struct yaffs_DeviceStruct *dev,
 static void yaffs_RetireBlock(yaffs_Device * dev, int blockInNAND)
 {
 
+       yaffs_InvalidateCheckpoint(dev);
+       
        yaffs_MarkBlockBad(dev, blockInNAND);
 
        yaffs_GetBlockInfo(dev, blockInNAND)->blockState =
@@ -620,7 +515,7 @@ static int yaffs_CreateTnodes(yaffs_Device * dev, int nTnodes)
 
 /* GetTnode gets us a clean tnode. Tries to make allocate more if we run out */
 
-static yaffs_Tnode *yaffs_GetTnode(yaffs_Device * dev)
+static yaffs_Tnode *yaffs_GetTnodeRaw(yaffs_Device * dev)
 {
        yaffs_Tnode *tn = NULL;
 
@@ -640,13 +535,21 @@ static yaffs_Tnode *yaffs_GetTnode(yaffs_Device * dev)
 #endif
                dev->freeTnodes = dev->freeTnodes->internal[0];
                dev->nFreeTnodes--;
-               /* zero out */
-               memset(tn, 0, (dev->tnodeWidth * YAFFS_NTNODES_LEVEL0)/8);
        }
 
        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)
 {
@@ -813,18 +716,21 @@ static yaffs_Tnode *yaffs_FindLevel0Tnode(yaffs_Device * dev,
  *  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)
+                                              __u32 chunkId,
+                                              yaffs_Tnode *passedTn)
 {
 
-       yaffs_Tnode *tn;
-
        int requiredTallness;
        int i;
        int l;
+       yaffs_Tnode *tn;
 
        __u32 x;
 
@@ -870,19 +776,42 @@ static yaffs_Tnode *yaffs_AddOrFindLevel0Tnode(yaffs_Device * dev,
 
        l = fStruct->topLevel;
        tn = fStruct->top;
-       while (l > 0 && tn) {
-               x = (chunkId >>
-                    ( YAFFS_TNODES_LEVEL0_BITS +
-                     (l - 1) * YAFFS_TNODES_INTERNAL_BITS)) &
-                   YAFFS_TNODES_INTERNAL_MASK;
-
-
-               if (!tn->internal[x])
-                       tn->internal[x] = yaffs_GetTnode(dev);
-
-               tn = tn->internal[x];
-               l--;
-
+       
+       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;
@@ -1569,6 +1498,7 @@ static yaffs_Object *yaffs_FindOrCreateObjectByNumber(yaffs_Device * dev,
        return theObject;
 
 }
+                       
 
 static YCHAR *yaffs_CloneString(const YCHAR * str)
 {
@@ -1819,8 +1749,10 @@ int yaffs_RenameObject(yaffs_Object * oldDir, const YCHAR * oldName,
 
 /*------------------------- Block Management and Page Allocation ----------------*/
 
-static int yaffs_InitialiseBlocks(yaffs_Device * dev, int nBlocks)
+static int yaffs_InitialiseBlocks(yaffs_Device * dev)
 {
+       int nBlocks = dev->internalEndBlock - dev->internalStartBlock + 1;
+       
        dev->allocationBlock = -1;      /* force it to get a new one */
 
        /* Todo we're assuming the malloc will pass. */
@@ -1833,7 +1765,7 @@ static int yaffs_InitialiseBlocks(yaffs_Device * dev, int nBlocks)
                dev->blockInfoAlt = 0;
        
        /* Set up dynamic blockinfo stuff. */
-       dev->chunkBitmapStride = (dev->nChunksPerBlock + 7) / 8;
+       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);
@@ -2005,6 +1937,7 @@ static void yaffs_BlockBecameDirty(yaffs_Device * dev, int blockNo)
        bi->blockState = YAFFS_BLOCK_STATE_DIRTY;
 
        if (!bi->needsRetiring) {
+               yaffs_InvalidateCheckpoint(dev);
                erasedOk = yaffs_EraseBlockInNAND(dev, blockNo);
                if (!erasedOk) {
                        dev->nErasureFailures++;
@@ -2601,8 +2534,10 @@ static int yaffs_PutChunkIntoFile(yaffs_Object * in, int chunkInInode,
                return YAFFS_OK;
        }
 
-       tn = yaffs_AddOrFindLevel0Tnode(dev, &in->variant.fileVariant,
-                                       chunkInInode);
+       tn = yaffs_AddOrFindLevel0Tnode(dev, 
+                                       &in->variant.fileVariant,
+                                       chunkInInode,
+                                       NULL);
        if (!tn) {
                return YAFFS_FAIL;
        }
@@ -3235,6 +3170,433 @@ static void yaffs_InvalidateWholeChunkCache(yaffs_Object * in)
        }
 }
 
+/*--------------------- Checkpointing --------------------*/
+
+
+static int yaffs_WriteCheckpointValidityMarker(yaffs_Device *dev,int head)
+{
+       yaffs_CheckpointValidity cp;
+       cp.structType = sizeof(cp);
+       cp.magic = YAFFS_MAGIC;
+       cp.version = 1;
+       cp.head = (head) ? 1 : 0;
+       
+       return (yaffs_CheckpointWrite(dev,&cp,sizeof(cp)) == sizeof(cp))?
+               1 : 0;
+}
+
+static int yaffs_ReadCheckpointValidityMarker(yaffs_Device *dev, int head)
+{
+       yaffs_CheckpointValidity cp;
+       int ok;
+       
+       ok = (yaffs_CheckpointRead(dev,&cp,sizeof(cp)) == sizeof(cp));
+       
+       if(ok)
+               ok = (cp.structType == sizeof(cp)) &&
+                    (cp.magic == YAFFS_MAGIC) &&
+                    (cp.version == 1) &&
+                    (cp.head == ((head) ? 1 : 0));
+       return ok ? 1 : 0;
+}
+
+static void yaffs_DeviceToCheckpointDevice(yaffs_CheckpointDevice *cp, 
+                                          yaffs_Device *dev)
+{
+       cp->nErasedBlocks = dev->nErasedBlocks;
+       cp->allocationBlock = dev->allocationBlock;
+       cp->allocationPage = dev->allocationPage;
+       cp->nFreeChunks = dev->nFreeChunks;
+       
+       cp->nDeletedFiles = dev->nDeletedFiles;
+       cp->nUnlinkedFiles = dev->nUnlinkedFiles;
+       cp->nBackgroundDeletions = dev->nBackgroundDeletions;
+       cp->sequenceNumber = dev->sequenceNumber;
+       cp->oldestDirtySequence = dev->oldestDirtySequence;
+       
+}
+
+static void yaffs_CheckpointDeviceToDevice(yaffs_Device *dev,
+                                          yaffs_CheckpointDevice *cp)
+{
+       dev->nErasedBlocks = cp->nErasedBlocks;
+       dev->allocationBlock = cp->allocationBlock;
+       dev->allocationPage = cp->allocationPage;
+       dev->nFreeChunks = cp->nFreeChunks;
+       
+       dev->nDeletedFiles = cp->nDeletedFiles;
+       dev->nUnlinkedFiles = cp->nUnlinkedFiles;
+       dev->nBackgroundDeletions = cp->nBackgroundDeletions;
+       dev->sequenceNumber = cp->sequenceNumber;
+       dev->oldestDirtySequence = cp->oldestDirtySequence;
+}
+
+
+static int yaffs_WriteCheckpointDevice(yaffs_Device *dev)
+{
+       yaffs_CheckpointDevice cp;
+       __u32 nBytes;
+       __u32 nBlocks = (dev->internalEndBlock - dev->internalStartBlock + 1);
+
+       int ok;
+               
+       /* Write device runtime values*/
+       yaffs_DeviceToCheckpointDevice(&cp,dev);
+       cp.structType = sizeof(cp);
+       
+       ok = (yaffs_CheckpointWrite(dev,&cp,sizeof(cp)) == sizeof(cp));
+       
+       /* Write block info */
+       if(ok) {
+               nBytes = nBlocks * sizeof(yaffs_BlockInfo);
+               ok = (yaffs_CheckpointWrite(dev,dev->blockInfo,nBytes) == nBytes);
+       }
+               
+       /* Write chunk bits */          
+       if(ok) {
+               nBytes = nBlocks * dev->chunkBitmapStride;
+               ok = (yaffs_CheckpointWrite(dev,dev->chunkBits,nBytes) == nBytes);
+       }
+       return   ok ? 1 : 0;
+
+}
+
+static int yaffs_ReadCheckpointDevice(yaffs_Device *dev)
+{
+       yaffs_CheckpointDevice cp;
+       __u32 nBytes;
+       __u32 nBlocks = (dev->internalEndBlock - dev->internalStartBlock + 1);
+
+       int ok; 
+       
+       ok = (yaffs_CheckpointRead(dev,&cp,sizeof(cp)) == sizeof(cp));
+       if(!ok)
+               return 0;
+               
+       if(cp.structType != sizeof(cp))
+               return 0;
+               
+       
+       yaffs_CheckpointDeviceToDevice(dev,&cp);
+       
+       nBytes = nBlocks * sizeof(yaffs_BlockInfo);
+       
+       ok = (yaffs_CheckpointRead(dev,dev->blockInfo,nBytes) == nBytes);
+       
+       if(!ok)
+               return 0;
+       nBytes = nBlocks * dev->chunkBitmapStride;
+       
+       ok = (yaffs_CheckpointRead(dev,dev->chunkBits,nBytes) == nBytes);
+       
+       return ok ? 1 : 0;
+}
+
+static void yaffs_ObjectToCheckpointObject(yaffs_CheckpointObject *cp,
+                                          yaffs_Object *obj)
+{
+
+       cp->objectId = obj->objectId;
+       cp->parentId = (obj->parent) ? obj->parent->objectId : 0;
+       cp->chunkId = obj->chunkId;
+       cp->variantType = obj->variantType;                     
+       cp->deleted = obj->deleted;
+       cp->softDeleted = obj->softDeleted;
+       cp->unlinked = obj->unlinked;
+       cp->fake = obj->fake;
+       cp->renameAllowed = obj->renameAllowed;
+       cp->unlinkAllowed = obj->unlinkAllowed;
+       cp->serial = obj->serial;
+       cp->nDataChunks = obj->nDataChunks;
+       
+       if(obj->variantType == YAFFS_OBJECT_TYPE_FILE)
+               cp->fileSizeOrEquivalentObjectId = obj->variant.fileVariant.fileSize;
+       else if(obj->variantType == YAFFS_OBJECT_TYPE_HARDLINK)
+               cp->fileSizeOrEquivalentObjectId = obj->variant.hardLinkVariant.equivalentObjectId;
+}
+
+static void yaffs_CheckpointObjectToObject( yaffs_Object *obj,yaffs_CheckpointObject *cp)
+{
+
+       yaffs_Object *parent;
+       
+       obj->objectId = cp->objectId;
+       
+       if(cp->parentId)
+               parent = yaffs_FindOrCreateObjectByNumber(
+                                       obj->myDev,
+                                       cp->parentId,
+                                       YAFFS_OBJECT_TYPE_DIRECTORY);
+       else
+               parent = NULL;
+               
+       if(parent)
+               yaffs_AddObjectToDirectory(parent, obj);
+               
+       obj->chunkId = cp->chunkId;
+       obj->variantType = cp->variantType;                     
+       obj->deleted = cp->deleted;
+       obj->softDeleted = cp->softDeleted;
+       obj->unlinked = cp->unlinked;
+       obj->fake = cp->fake;
+       obj->renameAllowed = cp->renameAllowed;
+       obj->unlinkAllowed = cp->unlinkAllowed;
+       obj->serial = cp->serial;
+       obj->nDataChunks = cp->nDataChunks;
+       
+       if(obj->variantType == YAFFS_OBJECT_TYPE_FILE)
+               obj->variant.fileVariant.fileSize = cp->fileSizeOrEquivalentObjectId;
+       else if(obj->variantType == YAFFS_OBJECT_TYPE_HARDLINK)
+               obj->variant.hardLinkVariant.equivalentObjectId = cp->fileSizeOrEquivalentObjectId;
+               
+       if(obj->objectId >= YAFFS_NOBJECT_BUCKETS)
+               obj->lazyLoaded = 1;
+}
+
+
+
+static int yaffs_CheckpointTnodeWorker(yaffs_Object * in, yaffs_Tnode * tn,
+                                       __u32 level, int chunkOffset)
+{
+       int i;
+       yaffs_Device *dev = in->myDev;
+
+       if (tn) {
+               if (level > 0) {
+
+                       for (i = 0; i < YAFFS_NTNODES_INTERNAL; i++){
+                               if (tn->internal[i]) {
+                                       yaffs_CheckpointTnodeWorker(in,
+                                                       tn->internal[i],
+                                                       level - 1,
+                                                       (chunkOffset<<YAFFS_TNODES_INTERNAL_BITS) + i);
+                               }
+                       }
+               } else if (level == 0) {
+                       __u32 baseOffset = chunkOffset <<  YAFFS_TNODES_LEVEL0_BITS;
+                       /* printf("write tnode at %d\n",baseOffset); */
+                       yaffs_CheckpointWrite(dev,&baseOffset,sizeof(baseOffset));
+                       yaffs_CheckpointWrite(dev,tn,(dev->tnodeWidth * YAFFS_NTNODES_LEVEL0)/8);
+               }
+       }
+
+       return 1;
+
+}
+
+static int yaffs_WriteCheckpointTnodes(yaffs_Object *obj)
+{
+       __u32 endMarker = ~0;
+       int ok;
+       
+       if(obj->variantType == YAFFS_OBJECT_TYPE_FILE){
+               ok = yaffs_CheckpointTnodeWorker(obj,
+                                           obj->variant.fileVariant.top,
+                                           obj->variant.fileVariant.topLevel,
+                                           0);
+               if(ok)
+                       ok = (yaffs_CheckpointWrite(obj->myDev,&endMarker,sizeof(endMarker)) == 
+                               sizeof(endMarker));
+       }
+       
+       return ok ? 1 : 0;
+}
+
+static int yaffs_ReadCheckpointTnodes(yaffs_Object *obj)
+{
+       __u32 baseChunk;
+       int ok = 1;
+       yaffs_Device *dev = obj->myDev;
+       yaffs_FileStructure *fileStructPtr = &obj->variant.fileVariant;
+       yaffs_Tnode *tn;
+       
+       ok = (yaffs_CheckpointRead(dev,&baseChunk,sizeof(baseChunk)) == sizeof(baseChunk));
+       
+       while(ok && (~baseChunk)){
+               /* Read level 0 tnode */
+               
+               /* printf("read  tnode at %d\n",baseChunk); */
+               tn = yaffs_GetTnodeRaw(dev);
+               if(tn)
+                       ok = (yaffs_CheckpointRead(dev,tn,(dev->tnodeWidth * YAFFS_NTNODES_LEVEL0)/8) ==
+                             (dev->tnodeWidth * YAFFS_NTNODES_LEVEL0)/8);
+               else
+                       ok = 0;
+                       
+               if(tn && ok){
+                       ok = yaffs_AddOrFindLevel0Tnode(dev,
+                                                       fileStructPtr,
+                                                       baseChunk,
+                                                       tn) ? 1 : 0;
+               }
+                       
+               if(ok)
+                       ok = (yaffs_CheckpointRead(dev,&baseChunk,sizeof(baseChunk)) == sizeof(baseChunk));
+               
+       }
+
+       return ok ? 1 : 0;      
+}
+
+static int yaffs_WriteCheckpointObjects(yaffs_Device *dev)
+{
+       yaffs_Object *obj;
+       yaffs_CheckpointObject cp;
+       int i;
+       int ok = 1;
+       struct list_head *lh;
+
+       
+       /* Iterate through the objects in each hash entry,
+        * dumping them to the checkpointing stream.
+        */
+        
+        for(i = 0; ok &&  i <  YAFFS_NOBJECT_BUCKETS; i++){
+               list_for_each(lh, &dev->objectBucket[i].list) {
+                       if (lh) {
+                               obj = list_entry(lh, yaffs_Object, hashLink);
+                               if (!obj->deferedFree) {
+                                       yaffs_ObjectToCheckpointObject(&cp,obj);
+                                       cp.structType = sizeof(cp);
+                                       /* printf("Write out object %d type %d\n",obj->objectId,obj->variantType); */
+                                       ok = (yaffs_CheckpointWrite(dev,&cp,sizeof(cp)) == sizeof(cp));
+                                       
+                                       if(ok && obj->variantType == YAFFS_OBJECT_TYPE_FILE){
+                                               ok = yaffs_WriteCheckpointTnodes(obj);
+                                       }
+                               }
+                       }
+               }
+        }
+        
+        /* Dump end of list */
+       memset(&cp,0xFF,sizeof(yaffs_CheckpointObject));
+       cp.structType = sizeof(cp);
+       
+       if(ok)
+               ok = (yaffs_CheckpointWrite(dev,&cp,sizeof(cp)) == sizeof(cp));
+               
+       return ok ? 1 : 0;
+}
+
+static int yaffs_ReadCheckpointObjects(yaffs_Device *dev)
+{
+       yaffs_Object *obj;
+       yaffs_CheckpointObject cp;
+       int ok = 1;
+       int done = 0;
+       yaffs_Object *hardList = NULL;
+       
+       while(ok && !done) {
+               ok = (yaffs_CheckpointRead(dev,&cp,sizeof(cp)) == sizeof(cp));
+               if(cp.structType != sizeof(cp)) {
+                       /* printf("structure parsing failed\n"); */
+                       ok = 0;
+               }
+                       
+               if(ok && cp.objectId == ~0)
+                       done = 1;
+               else {
+                       /* printf("Read object %d type %d\n",cp.objectId,cp.variantType); */
+                       obj = yaffs_FindOrCreateObjectByNumber(dev,cp.objectId, cp.variantType);
+                       if(obj) {
+                               yaffs_CheckpointObjectToObject(obj,&cp);
+                               if(obj->variantType == YAFFS_OBJECT_TYPE_FILE) {
+                                       yaffs_ReadCheckpointTnodes(obj);
+                               } else if(obj->variantType == YAFFS_OBJECT_TYPE_HARDLINK) {
+                                       obj->hardLinks.next =
+                                                   (struct list_head *)
+                                                   hardList;
+                                       hardList = obj;
+                               }
+                          
+                       }
+               }
+       }
+       
+       if(ok)
+               yaffs_HardlinkFixup(dev,hardList);
+       
+       return ok ? 1 : 0;
+}
+
+static int yaffs_WriteCheckpointData(yaffs_Device *dev)
+{
+
+       int ok;
+       
+       ok = yaffs_CheckpointOpen(dev,1);
+       
+       if(ok)
+               ok = yaffs_WriteCheckpointValidityMarker(dev,1);
+       if(ok)
+               ok = yaffs_WriteCheckpointDevice(dev);
+       if(ok)
+               ok = yaffs_WriteCheckpointObjects(dev);
+       if(ok)
+               ok = yaffs_WriteCheckpointValidityMarker(dev,0);
+               
+       yaffs_CheckpointClose(dev);
+               
+       if(ok)
+               dev->isCheckpointed = 1;
+        else 
+               dev->isCheckpointed = 0;
+
+       return dev->isCheckpointed;
+}
+
+static int yaffs_ReadCheckpointData(yaffs_Device *dev)
+{
+       int ok;
+       
+       ok = yaffs_CheckpointOpen(dev,0); /* open for read */
+       
+       if(ok)
+               ok = yaffs_ReadCheckpointValidityMarker(dev,1);
+       if(ok)
+               ok = yaffs_ReadCheckpointDevice(dev);
+       if(ok)
+               ok = yaffs_ReadCheckpointObjects(dev);
+       if(ok)
+               ok = yaffs_ReadCheckpointValidityMarker(dev,0);
+               
+               
+       if(ok)
+               dev->isCheckpointed = 1;
+        else 
+               dev->isCheckpointed = 0;
+
+       yaffs_CheckpointClose(dev);
+
+       return ok ? 1 : 0;
+
+}
+
+static void yaffs_InvalidateCheckpoint(yaffs_Device *dev)
+{
+       if(dev->isCheckpointed){
+               dev->isCheckpointed = 0;
+               yaffs_CheckpointInvalidateStream(dev);
+       }
+}
+
+
+int yaffs_CheckpointSave(yaffs_Device *dev)
+{
+       if(!dev->isCheckpointed)
+               yaffs_WriteCheckpointData(dev);
+       
+       return dev->isCheckpointed;
+}
+
+int yaffs_CheckpointRestore(yaffs_Device *dev)
+{
+       
+       return yaffs_ReadCheckpointData(dev);
+}
+
 /*--------------------- File read/write ------------------------
  * Read and write have very similar structures.
  * In general the read/write has three parts to it
@@ -3947,6 +4309,41 @@ typedef struct {
        int block;
 } yaffs_BlockIndex;
 
+
+static void yaffs_HardlinkFixup(yaffs_Device *dev, yaffs_Object *hardList)
+{
+       yaffs_Object *hl;
+       yaffs_Object *in;
+       
+       while (hardList) {
+               hl = hardList;
+               hardList = (yaffs_Object *) (hardList->hardLinks.next);
+
+               in = yaffs_FindObjectByNumber(dev,
+                                             hl->variant.hardLinkVariant.
+                                             equivalentObjectId);
+
+               if (in) {
+                       /* Add the hardlink pointers */
+                       hl->variant.hardLinkVariant.equivalentObject = in;
+                       list_add(&hl->hardLinks, &in->hardLinks);
+               } else {
+                       /* Todo Need to report/handle this better.
+                        * Got a problem... hardlink to a non-existant object
+                        */
+                       hl->variant.hardLinkVariant.equivalentObject = NULL;
+                       INIT_LIST_HEAD(&hl->hardLinks);
+
+               }
+
+       }
+
+}
+
+
+
+
+
 static int yaffs_Scan(yaffs_Device * dev)
 {
        yaffs_ExtendedTags tags;
@@ -4394,33 +4791,14 @@ static int yaffs_Scan(yaffs_Device * dev)
                YFREE(blockIndex);
        }
        
+       
        /* Ok, we've done all the scanning.
         * Fix up the hard link chains.
         * We should now have scanned all the objects, now it's time to add these 
         * hardlinks.
         */
-       while (hardList) {
-               hl = hardList;
-               hardList = (yaffs_Object *) (hardList->hardLinks.next);
-
-               in = yaffs_FindObjectByNumber(dev,
-                                             hl->variant.hardLinkVariant.
-                                             equivalentObjectId);
-
-               if (in) {
-                       /* Add the hardlink pointers */
-                       hl->variant.hardLinkVariant.equivalentObject = in;
-                       list_add(&hl->hardLinks, &in->hardLinks);
-               } else {
-                       /* Todo Need to report/handle this better.
-                        * Got a problem... hardlink to a non-existant object
-                        */
-                       hl->variant.hardLinkVariant.equivalentObject = NULL;
-                       INIT_LIST_HEAD(&hl->hardLinks);
-
-               }
 
-       }
+       yaffs_HardlinkFixup(dev,hardList);
 
        /* Handle the unlinked files. Since they were left in an unlinked state we should
         * just delete them.
@@ -4502,7 +4880,6 @@ static int yaffs_ScanBackwards(yaffs_Device * dev)
        int deleted;
        yaffs_BlockState state;
        yaffs_Object *hardList = NULL;
-       yaffs_Object *hl;
        yaffs_BlockInfo *bi;
        int sequenceNumber;
        yaffs_ObjectHeader *oh;
@@ -5040,29 +5417,12 @@ static int yaffs_ScanBackwards(yaffs_Device * dev)
         * We should now have scanned all the objects, now it's time to add these 
         * hardlinks.
         */
-       while (hardList) {
-               hl = hardList;
-               hardList = (yaffs_Object *) (hardList->hardLinks.next);
-
-               in = yaffs_FindObjectByNumber(dev,
-                                             hl->variant.hardLinkVariant.
-                                             equivalentObjectId);
-
-               if (in) {
-                       /* Add the hardlink pointers */
-                       hl->variant.hardLinkVariant.equivalentObject = in;
-                       list_add(&hl->hardLinks, &in->hardLinks);
-               } else {
-                       /* Todo Need to report/handle this better.
-                        * Got a problem... hardlink to a non-existant object
-                        */
-                       hl->variant.hardLinkVariant.equivalentObject = NULL;
-                       INIT_LIST_HEAD(&hl->hardLinks);
-
-               }
-
-       }
-
+       yaffs_HardlinkFixup(dev,hardList);
+       
+       
+       /*
+       *  Sort out state of unlinked and deleted objects.
+       */
        {
                struct list_head *i;
                struct list_head *n;
@@ -5490,12 +5850,33 @@ static int yaffs_CheckDevFunctions(const yaffs_Device * dev)
        return 0;               /* bad */
 }
 
+
+static void yaffs_CreateInitialDirectories(yaffs_Device *dev)
+{
+       /* Initialise the unlinked, deleted, root and lost and found directories */
+       
+       dev->lostNFoundDir = dev->rootDir =  NULL;
+       dev->unlinkedDir = dev->deletedDir = NULL;
+
+       dev->unlinkedDir =
+           yaffs_CreateFakeDirectory(dev, YAFFS_OBJECTID_UNLINKED, S_IFDIR);
+       dev->deletedDir =
+           yaffs_CreateFakeDirectory(dev, YAFFS_OBJECTID_DELETED, S_IFDIR);
+
+       dev->rootDir =
+           yaffs_CreateFakeDirectory(dev, YAFFS_OBJECTID_ROOT,
+                                     YAFFS_ROOT_MODE | S_IFDIR);
+       dev->lostNFoundDir =
+           yaffs_CreateFakeDirectory(dev, YAFFS_OBJECTID_LOSTNFOUND,
+                                     YAFFS_LOSTNFOUND_MODE | S_IFDIR);
+       yaffs_AddObjectToDirectory(dev->rootDir, dev->lostNFoundDir);
+}
+
 int yaffs_GutsInitialise(yaffs_Device * dev)
 {
        unsigned x;
        int bits;
        int extraBits;
-       int nBlocks;
 
        T(YAFFS_TRACE_TRACING, (TSTR("yaffs: yaffs_GutsInitialise()" TENDSTR)));
 
@@ -5521,7 +5902,13 @@ int yaffs_GutsInitialise(yaffs_Device * dev)
 
        /* Check geometry parameters. */
 
-       if ((dev->isYaffs2 && dev->nBytesPerChunk < 1024) || (!dev->isYaffs2 && dev->nBytesPerChunk != 512) || dev->nChunksPerBlock < 2 || dev->nReservedBlocks < 2 || dev->internalStartBlock <= 0 || dev->internalEndBlock <= 0 || dev->internalEndBlock <= (dev->internalStartBlock + dev->nReservedBlocks + 2)      // otherwise it is too small
+       if ((dev->isYaffs2 && dev->nBytesPerChunk < 1024) || 
+           (!dev->isYaffs2 && dev->nBytesPerChunk != 512) || 
+            dev->nChunksPerBlock < 2 || 
+            dev->nReservedBlocks < 2 || 
+            dev->internalStartBlock <= 0 || 
+            dev->internalEndBlock <= 0 || 
+            dev->internalEndBlock <= (dev->internalStartBlock + dev->nReservedBlocks + 2)      // otherwise it is too small
            ) {
                T(YAFFS_TRACE_ALWAYS,
                  (TSTR
@@ -5563,7 +5950,7 @@ int yaffs_GutsInitialise(yaffs_Device * dev)
 
        dev->isMounted = 1;
 
-       nBlocks = dev->internalEndBlock - dev->internalStartBlock + 1;
+
 
        /* OK now calculate a few things for the device
         * Calculate chunkGroupBits.
@@ -5640,7 +6027,7 @@ int yaffs_GutsInitialise(yaffs_Device * dev)
        dev->nErasedBlocks = 0;
        dev->isDoingGC = 0;
 
-       /* Initialise temporary buffers */
+       /* Initialise temporary buffers and caches. */
        {
                int i;
                for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
@@ -5649,15 +6036,7 @@ int yaffs_GutsInitialise(yaffs_Device * dev)
                            YMALLOC(dev->nBytesPerChunk);
                }
        }
-
-       yaffs_InitialiseBlocks(dev, nBlocks);
-
-       yaffs_InitialiseTnodes(dev);
-
-       yaffs_InitialiseObjects(dev);
-
-       dev->gcCleanupList = YMALLOC(dev->nChunksPerBlock * sizeof(__u32));
-
+       
        if (dev->nShortOpCaches > 0) {
                int i;
 
@@ -5678,32 +6057,41 @@ int yaffs_GutsInitialise(yaffs_Device * dev)
        }
 
        dev->cacheHits = 0;
+       
+       dev->gcCleanupList = YMALLOC(dev->nChunksPerBlock * sizeof(__u32));
 
-       /* Initialise the unlinked, root and lost and found directories */
-       dev->lostNFoundDir = dev->rootDir =  NULL;
-       dev->unlinkedDir = dev->deletedDir = NULL;
+       if (dev->isYaffs2) {
+               dev->useHeaderFileSize = 1;
+       }
 
-       dev->unlinkedDir =
-           yaffs_CreateFakeDirectory(dev, YAFFS_OBJECTID_UNLINKED, S_IFDIR);
-       dev->deletedDir =
-           yaffs_CreateFakeDirectory(dev, YAFFS_OBJECTID_DELETED, S_IFDIR);
+       yaffs_InitialiseBlocks(dev);
+       yaffs_InitialiseTnodes(dev);
+       yaffs_InitialiseObjects(dev);
+
+       yaffs_CreateInitialDirectories(dev);
 
-       dev->rootDir =
-           yaffs_CreateFakeDirectory(dev, YAFFS_OBJECTID_ROOT,
-                                     YAFFS_ROOT_MODE | S_IFDIR);
-       dev->lostNFoundDir =
-           yaffs_CreateFakeDirectory(dev, YAFFS_OBJECTID_LOSTNFOUND,
-                                     YAFFS_LOSTNFOUND_MODE | S_IFDIR);
-       yaffs_AddObjectToDirectory(dev->rootDir, dev->lostNFoundDir);
 
+       /* Now scan the flash. */
        if (dev->isYaffs2) {
-               dev->useHeaderFileSize = 1;
-       }
+               if(yaffs_CheckpointRestore(dev)) {
+                       T(YAFFS_TRACE_ALWAYS,
+                         (TSTR("yaffs: restored from checkpoint" TENDSTR)));
+               } else {
 
-       /* Now scan the flash.   */
-       if (dev->isYaffs2)
-               yaffs_ScanBackwards(dev);
-       else
+                       /* Clean up the mess caused by an aborted checkpoint load 
+                        * and scan backwards. 
+                        */
+                       yaffs_DeinitialiseBlocks(dev);
+                       yaffs_DeinitialiseTnodes(dev);
+                       yaffs_DeinitialiseObjects(dev);
+                       yaffs_InitialiseBlocks(dev);
+                       yaffs_InitialiseTnodes(dev);
+                       yaffs_InitialiseObjects(dev);
+                       yaffs_CreateInitialDirectories(dev);
+
+                       yaffs_ScanBackwards(dev);
+               }
+       }else
                yaffs_Scan(dev);
 
        /* Zero out stats */