userlibandfileserver/fileserver/sfat/sl_scan.cpp
changeset 9 96e5fb8b040d
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/userlibandfileserver/fileserver/sfat/sl_scan.cpp	Thu Dec 17 09:24:54 2009 +0200
@@ -0,0 +1,696 @@
+// Copyright (c) 1998-2009 Nokia Corporation and/or its subsidiary(-ies).
+// All rights reserved.
+// This component and the accompanying materials are made available
+// under the terms of the License "Eclipse Public License v1.0"
+// which accompanies this distribution, and is available
+// at the URL "http://www.eclipse.org/legal/epl-v10.html".
+//
+// Initial Contributors:
+// Nokia Corporation - initial contribution.
+//
+// Contributors:
+//
+// Description:
+// f32\sfat\sl_scan.cpp
+// ScanDrive code, specific for EFAT.FSY
+// 
+//
+
+/**
+ @file
+ @internalTechnology
+*/
+
+//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+//!!
+//!! WARNING!! DO NOT edit this file !! '\sfat' component is obsolete and is not being used. '\sfat32'replaces it
+//!!
+//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+
+//#define DEBUG_SCANDRIVE
+
+#include "sl_std.h"
+#include "sl_scandrv.h"
+
+const TInt KEndOfDirectory          = 0xFFFF;   ///< End of directory marker
+const TInt KMaxScanDepth            = 20;       ///< Maximum scan depth of to avoid stack over flow 
+const TInt KClusterListGranularity  = 8;        ///< Granularity of cluster list used for storage of clusters when KMaxScanDepth is reached
+
+/**
+Creates a CScanDrive
+
+@param aMount The owning mount
+*/
+CScanDrive* CScanDrive::NewL(CFatMountCB* aMount)
+    {
+    if(aMount==NULL)
+        User::Leave(KErrArgument);
+    CScanDrive* self=new (ELeave) CScanDrive();
+    CleanupStack::PushL(self);
+    self->ConstructL(aMount);
+    CleanupStack::Pop();
+    return self;
+    }
+
+
+CScanDrive::CScanDrive()
+//
+// Constructor
+//
+    {
+    }
+
+
+CScanDrive::~CScanDrive()
+//
+// Destructor
+//
+    {
+    delete iNewFat;
+    for(TInt i=0;i<KMaxArrayDepth && iClusterListArray[i]!=NULL;++i)
+        {
+        iClusterListArray[i]->Close();
+        delete iClusterListArray[i];
+        }
+    }
+
+
+void CScanDrive::ConstructL(CFatMountCB* aMount)
+//
+// Create the new fat and initalise
+//
+    {
+    iMount=aMount;
+    iNewFat=CCheckFatTable::NewL(aMount);
+    iNewFat->InitializeL();
+    }
+
+
+TBool CScanDrive::AlreadyExistsL(TInt aCluster)const
+//
+//  Return ETrue if aCluster in the new fat contains a non-zero entry
+//
+    {
+    return(iNewFat->ReadL(aCluster)!=0);
+    }
+
+
+TBool CScanDrive::IsEndOfRootDir(const TEntryPos& aPos)const
+//
+// Return ETrue if aPos is the last entry in the root directory
+//
+    {
+    return(iMount->IsRootDir(aPos)&&(iMount->StartOfRootDirInBytes()+aPos.iPos==(iMount->RootDirEnd()-KSizeOfFatDirEntry)));
+    }
+
+/**
+@param aVal Value of the cluster to be tested
+@return ETrue if aVal is the end of cluster marker
+*/
+TBool CScanDrive::IsEofF(TInt aVal)const 
+    {
+    return iMount->IsEndOfClusterCh(aVal);
+    }
+
+/**
+@return True if a directory error has been found
+*/
+TBool CScanDrive::IsDirError()const
+    {
+    return(iDirError!=0);
+    }
+
+
+
+/**
+    After StartL() and finishing allows us to know if there were any problems at all.
+    The client may wish to remount the filesystem if there were errors.
+
+    @return EFalse if there were no problems in FS.
+*/
+TBool CScanDrive::ProblemsDiscovered() const
+{
+    return IsDirError() || iFoundProblems;
+}
+
+/**
+    Sets the flag indicating than there are errors in filesystem structure
+    See ProblemsDiscovered()
+*/
+void CScanDrive::IndicateErrorsFound()
+{
+    iFoundProblems = ETrue;
+}
+
+
+
+/**
+Start point for scan drive also fixes up errors 
+
+@return The result of the scan
+@leave 
+*/
+TInt CScanDrive::StartL()
+    {
+    __PRINT(_L("CScanDrive::StartL"));
+    // check directory structure
+    CheckDirStructureL();
+#if defined(DEBUG_SCANDRIVE)
+    CompareFatsL();
+#endif
+    // fix error in directory structure
+    if(IsDirError())
+        FixupDirErrorL();
+    // flush new fat
+    WriteNewFatsL();
+#if defined(DEBUG_SCANDRIVE)
+    PrintErrors();
+#endif
+    return KErrNone;
+    }
+
+/**
+Fix errors detected by the drive scan
+
+@leave System wide error code
+*/
+void CScanDrive::FixupDirErrorL()
+    {
+    if(!IsDirError())
+        return;
+    if(iDirError==EScanMatchingEntry)
+        {
+        FindSameStartClusterL();
+        FixMatchingEntryL();
+        }
+    else
+        {
+        FixPartEntryL();
+        }
+
+    IndicateErrorsFound(); //-- indicate that we have found errors
+    }
+
+/**
+Find positions of entries with same start cluster for error correction, searches
+the whole volume. Starts at the root directory. 
+
+@leave System wide error code
+*/
+void CScanDrive::FindSameStartClusterL()
+    {
+    TInt err=FindStartClusterL(0);
+    if(err==KErrNone)
+        return;
+    for(TInt i=0;i<KMaxArrayDepth && iClusterListArray[i]!=NULL;++i)
+        {
+        RArray<TInt>* clusterList=iClusterListArray[i];
+        for(TInt j=0;j<clusterList->Count();++j)
+            {
+            iRecursiveDepth=0;
+            err=FindStartClusterL((*clusterList)[j]);
+            if(err==KErrNone)
+                return;
+            }
+        }
+    __ASSERT_ALWAYS(err==KErrNone,User::Leave(KErrNotFound));
+    }
+/**
+Scan through directory structure looking for start cluster found in iMatching
+
+@param aDirCluster Start cluster for scan to start
+@return System wide error value
+@leave 
+*/
+TInt CScanDrive::FindStartClusterL(TInt aDirCluster)
+    {
+    __PRINT1(_L("CScanDrive::FindStartCluster dirCluster=%d"),aDirCluster);
+    __ASSERT_ALWAYS(aDirCluster>=0,User::Leave(KErrCorrupt));
+    if(++iRecursiveDepth==KMaxScanDepth)
+        {
+        --iRecursiveDepth;
+        return(KErrNotFound);
+        }
+    TEntryPos entryPos(aDirCluster,0);
+    TInt dirEntries=0;
+    FOREVER
+        {
+        TFatDirEntry entry;
+        iMount->ReadDirEntryL(entryPos,entry);
+        if(entry.IsParentDirectory()||entry.IsCurrentDirectory()||entry.IsErased())
+            {
+            if(IsEndOfRootDir(entryPos))
+                break;
+            iMount->MoveToNextEntryL(entryPos);
+            continue;
+            }
+        if(entry.IsEndOfDirectory())
+            break;
+        TBool isComplete;
+        TEntryPos vfatPos=entryPos;
+        isComplete=MoveToVFatEndL(entryPos,entry,dirEntries);
+        __ASSERT_ALWAYS(isComplete,User::Leave(KErrBadName));
+        TInt err=CheckEntryClusterL(entry,vfatPos);
+        if(err==KErrNone)
+            {
+            --iRecursiveDepth;
+            return(err);
+            }
+        if(IsEndOfRootDir(entryPos))
+            break;
+        iMount->MoveToNextEntryL(entryPos);
+        }
+    --iRecursiveDepth;
+    return(KErrNotFound);
+    }
+
+/**
+Procces aEntry to find matching start cluster
+
+@param aEntry Directory entry to check
+@param aEntryPos Position of directory to check
+@return System wide error value
+@leave 
+*/
+TInt CScanDrive::CheckEntryClusterL(const TFatDirEntry& aEntry, const TEntryPos& aEntryPos)
+    {
+    __PRINT(_L("CScanDrive::CheckEntryClusterL"));
+    if(iMount->StartCluster(aEntry)==iMatching.iStartCluster)
+        {
+        TBool complete=AddMatchingEntryL(aEntryPos);
+        if(complete)
+            return(KErrNone);
+        }
+    else if(aEntry.Attributes()&KEntryAttDir)
+        return(FindStartClusterL(iMount->StartCluster(aEntry)));
+    return(KErrNotFound);
+    }
+
+/**
+Checks directory strucutre for errors, can be considered the start point of the scan.  
+Handles recursion depth to avoid stack overflow.
+
+@leave System wide error code
+*/
+void CScanDrive::CheckDirStructureL()
+    {
+    CheckDirL(iMount->RootIndicator());
+    // Due to recursive nature of CheckDirL when a depth of
+    // KMaxScanDepth is reached clusters are stored in a list
+    // and passed into CheckDirL afresh
+    for(TInt i=0;i<KMaxArrayDepth && iClusterListArray[i]!=NULL;++i)
+        {
+        RArray<TInt>* clusterList=iClusterListArray[i];
+        ++iListArrayIndex;
+        for(TInt j=0;j<clusterList->Count();++j)
+            {
+            iRecursiveDepth=0;
+            CheckDirL((*clusterList)[j]);
+            }
+        }
+    }
+/**
+Function is called recursively with Process entry untill the whole volume has been scanned.
+Each directory entry is scanned for errors, these are recorded for later fixing. 
+
+@param aCluster Directory cluster to start checking
+@leave System wide error codes
+*/
+void CScanDrive::CheckDirL(TInt aCluster)
+    {
+    __PRINT1(_L("CScanDrive::CheckDirL aCluster=%d"),aCluster);
+    __ASSERT_ALWAYS(aCluster>=0,User::Leave(KErrCorrupt));
+    // check depth of recursion
+    if(++iRecursiveDepth==KMaxScanDepth)
+        {
+        AddToClusterListL(aCluster);
+        --iRecursiveDepth;
+        return;
+        }
+#if defined(DEBUG_SCANDRIVE)
+    ++iDirsChecked;
+#endif
+    TEntryPos entryPos(aCluster,0);
+    TInt dirEntries=0;
+    FOREVER
+        {
+        TFatDirEntry entry;
+        iMount->ReadDirEntryL(entryPos,entry);
+        if(!iMount->IsEndOfClusterCh(entryPos.iCluster))
+            ++dirEntries;
+        if(entry.IsParentDirectory()||entry.IsCurrentDirectory()||entry.IsErased())
+            {
+            if(IsEndOfRootDir(entryPos))
+                break;
+            iMount->MoveToNextEntryL(entryPos);
+            continue;
+            }
+        if(entry.IsEndOfDirectory())
+            {
+            if(aCluster)    
+                WriteClusterChainL(aCluster,dirEntries<<KSizeOfFatDirEntryLog2);
+            break;
+            }
+        TEntryPos origPos=entryPos;
+        TFatDirEntry origEntry=entry;
+        TInt origDirEntries=dirEntries;
+        TBool isComplete;
+        isComplete=MoveToVFatEndL(entryPos,entry,dirEntries);
+        // Only assume that this is a corrupted VFAT entry if the VFAT attributes are set; 
+        // assuming a non-VFAT corrupted entry is a VFAT entry is dangerous as we then assume that the 
+        // first byte is a count of entries to skip, thus completely invalidating the next <n> directories.
+        if (!isComplete && origEntry.IsVFatEntry())
+            {
+            AddPartialVFatL(origPos,origEntry);
+            if(entryPos.iCluster!=KEndOfDirectory)
+                {
+                TInt toMove=origEntry.NumFollowing()-(dirEntries-origDirEntries);
+                if(toMove)
+                    MovePastEntriesL(entryPos,entry,toMove,dirEntries);
+                }
+            else
+                {
+                // we fell off the end of the directory file, so just strip this
+                // incomplete long file name entry
+                dirEntries = origDirEntries;
+                }
+            }
+        else
+            ProcessEntryL(entry);
+        if(IsEndOfRootDir(entryPos))
+            break;
+        iMount->MoveToNextEntryL(entryPos);
+        }
+    --iRecursiveDepth;
+    }
+
+/**
+Process non trivial entries, such as files, if they are correct by filling out their 
+cluster allocation in the bit packed Fat table. If it comes accross a directory 
+CheckDirL will be called.
+
+@param aEntry Directory entry to check
+@leave System wide error code
+*/
+void CScanDrive::ProcessEntryL(const TFatDirEntry& aEntry)
+    {
+    __PRINT(_L("CScanDrive::ProcessEntryL"));
+    TInt entryAtt=aEntry.Attributes();
+    __ASSERT_ALWAYS(!(entryAtt&~KEntryAttMaskSupported)&&!aEntry.IsErased(),User::Leave(KErrCorrupt));
+    if(!(entryAtt&(KEntryAttDir|KEntryAttVolume)) && iMount->StartCluster(aEntry)>0)
+        WriteClusterChainL(iMount->StartCluster(aEntry),aEntry.Size());
+    else if(entryAtt&KEntryAttDir)
+        CheckDirL(iMount->StartCluster(aEntry));
+    }
+
+/**
+Writes out the cluster chain for a correct file or directory, checks that the cluster 
+has not already been used and that the correct number of clusters are allocated for the 
+size of file. Registers cluster as used if correct
+
+@param aCluster Cluster chain start point
+@param aSizeInBytes Size of the file or directory in bytes
+@leave System wide error values
+*/
+void CScanDrive::WriteClusterChainL(TInt aCluster,TInt aSizeInBytes)
+//
+// Mark off in the new fat the clusters used by entry with start cluster of aCluster
+//
+    {
+
+    IndicateErrorsFound(); //-- indicate that we have found errors
+
+    __PRINT1(_L("CScanDrive::WriteClusterChainL starting at %d"),aCluster);
+    __ASSERT_ALWAYS(aCluster>0 && aSizeInBytes>=0,User::Leave(KErrCorrupt));
+    TInt clusterCount;
+    if(aSizeInBytes==0)
+        clusterCount=1;
+    else
+        clusterCount=(aSizeInBytes+(1<<iMount->ClusterSizeLog2())-1)>>iMount->ClusterSizeLog2();
+    TInt startCluster=aCluster;
+    while(clusterCount)
+        {
+        if(AlreadyExistsL(aCluster))
+            {
+            __ASSERT_ALWAYS(!IsDirError()&&iMatching.iStartCluster==0&&aCluster==startCluster,User::Leave(KErrCorrupt));
+            iMatching.iStartCluster=aCluster;
+            iDirError=EScanMatchingEntry;
+            return;
+            }
+        if(clusterCount==1)
+            {
+            iNewFat->WriteFatEntryEofFL(aCluster);
+            return;
+            }
+        else
+            {
+            TInt clusterVal;
+            clusterVal=iMount->FAT().ReadL(aCluster);
+            __ASSERT_ALWAYS(!IsEofF(clusterVal) && clusterVal!=0,User::Leave(KErrCorrupt));
+            iNewFat->WriteL(aCluster,clusterVal);
+            aCluster=clusterVal;
+            --clusterCount;
+            }
+        }
+    }
+
+/**
+Move to dos entry, checking all vfat entry ID numbers are in sequence.
+Assumes aEntry is not erased
+
+@param aPos Position of the entry to move from, returns with new position
+@param aEntry The Dos entry after the Vfat entries on return
+@param aDirLength Running total of the length of the directory in entries
+@leave System wide error codes
+@return EFalse if not valid vfat entries or dos entry, else returns ETrue
+*/
+TBool CScanDrive::MoveToVFatEndL(TEntryPos& aPos,TFatDirEntry& aEntry,TInt& aDirLength)
+    {
+    __PRINT2(_L("CScanDrive::MoveToVFatEndL cluster=%d,pos=%d"),aPos.iCluster,aPos.iPos);
+    if(!aEntry.IsVFatEntry())
+        return IsDosEntry(aEntry);
+    TInt toFollow=aEntry.NumFollowing();
+    __ASSERT_ALWAYS(toFollow>0&&!aEntry.IsErased(),User::Leave(KErrCorrupt));
+    FOREVER
+        {
+        iMount->MoveToNextEntryL(aPos);
+        iMount->ReadDirEntryL(aPos,aEntry);
+        ++aDirLength;
+        --toFollow;
+        if(!toFollow)
+            break;
+        if(!IsValidVFatEntry(aEntry,toFollow))
+            return(EFalse);
+        }
+    return(IsDosEntry(aEntry));
+    }
+
+/**
+Check if an entry is valid VFat
+
+@param aEntry Entry to check
+@param aPrevNum Number into VFat entries for a dos entry to ensure in correct position
+@return ETrue if aEntry is a valid vfat entry
+*/
+TBool CScanDrive::IsValidVFatEntry(const TFatDirEntry& aEntry, TInt aPrevNum)const
+    {
+    if(aEntry.IsErased()||!aEntry.IsVFatEntry())
+        return(EFalse);
+    return(aEntry.NumFollowing()==aPrevNum);
+    }
+
+/**
+Check if an entry is a Dos entry
+
+@param aEntry Entry to check
+@return ETrue if aEntry is a dos entry
+*/
+TBool CScanDrive::IsDosEntry(const TFatDirEntry& aEntry)const
+    {
+    TBool res = !(aEntry.Attributes()&~KEntryAttMaskSupported) && !aEntry.IsErased() && !aEntry.IsVFatEntry() && !aEntry.IsEndOfDirectory();
+    return res;
+    } 
+
+/**
+Add partial entry to iPartEntry under the error condition of not all Vfat entries 
+being present
+
+@param aStartPos Position of the Dos entry associated with the VFat entries
+@param aEntry Directory Entry of the Dos entry associated with the VFat entries
+@leave KErrCorrupt Occurs if the entry is not valid
+*/
+void CScanDrive::AddPartialVFatL(const TEntryPos& aStartPos, const TFatDirEntry& aEntry)
+    {
+    __PRINT2(_L("CScanDrive::AddPartialVFatL cluster=%d pos=%d"),aStartPos.iCluster,aStartPos.iPos);
+    __ASSERT_ALWAYS(!IsDirError(),User::Leave(KErrCorrupt));
+    iPartEntry.iEntryPos=aStartPos;
+    iPartEntry.iEntry=aEntry;
+    iDirError=EScanPartEntry;
+    }
+
+/**
+Add entry position to iMatching
+
+@param aEntryPos Position of the entry with the matching entry
+@leave KErrCorrupt if the start cluster is 0 or more that two matching entries occurs
+@return 
+*/
+TBool CScanDrive::AddMatchingEntryL(const TEntryPos& aEntryPos)
+    {
+    __PRINT2(_L("CScanDrive::AddMatchingEntryL cluster=%d pos=%d"),aEntryPos.iCluster,aEntryPos.iPos);
+    __ASSERT_ALWAYS(iMatching.iStartCluster>0 && iMatching.iCount<KMaxMatchingEntries,User::Leave(KErrCorrupt));
+    iMatching.iEntries[iMatching.iCount++]=aEntryPos;
+    return iMatching.iCount==KMaxMatchingEntries;
+    }
+
+
+/**
+Scan for differnces in the new and old FAT table writing them to media if discovered
+
+@leave System wide error codes
+*/
+void CScanDrive::WriteNewFatsL()
+//
+// Write the new fat table to disk
+//
+    {
+    if(iNewFat->FlushL())
+        IndicateErrorsFound(); //-- indicate that we have found errors       
+    }
+
+TInt CScanDrive::GetReservedidL(TEntryPos aVFatPos)
+//
+// Return the id found in reserved2 field of dos entry
+//
+    {
+    __PRINT(_L("CScanDrive::GetReservedidL"));
+    TFatDirEntry entry;
+    iMount->ReadDirEntryL(aVFatPos,entry);
+    if(!IsDosEntry(entry))
+        {
+        TInt toMove=entry.NumFollowing();
+        while(toMove--)
+            iMount->MoveToNextEntryL(aVFatPos);
+        iMount->ReadDirEntryL(aVFatPos,entry);
+        }
+    return(entry.RuggedFatEntryId());
+    }
+
+/**
+Erase part entry found in iPartEntry
+
+@leave System wide error code
+*/
+void CScanDrive::FixPartEntryL()
+    {
+    __PRINT2(_L("CScanDrive::FixPartEntryL cluster=%d,pos=%d"),iPartEntry.iEntryPos.iCluster,iPartEntry.iEntryPos.iPos);
+    iMount->EraseDirEntryL(iPartEntry.iEntryPos,iPartEntry.iEntry);
+    IndicateErrorsFound(); //-- indicate that we have found errors
+    }
+    
+/**
+Delete entry with largest value in the reserved2 section(bytes 20 and 21) of dos entry
+    
+@leave System wide error code
+*/
+void CScanDrive::FixMatchingEntryL()
+    {
+    __PRINT1(_L("CScanDrive::FixMatchingEntryL() start cluster=%d"),iMatching.iStartCluster);
+    __ASSERT_ALWAYS(iMatching.iCount==KMaxMatchingEntries,User::Leave(KErrCorrupt));
+    TInt idOne=GetReservedidL(iMatching.iEntries[0]);
+    TInt idTwo=GetReservedidL(iMatching.iEntries[1]);
+    TFatDirEntry entry;
+    TInt num=idOne>idTwo?0:1;
+    iMount->ReadDirEntryL(iMatching.iEntries[num],entry);
+    iMount->EraseDirEntryL(iMatching.iEntries[num],entry);
+    IndicateErrorsFound(); //-- indicate that we have found errors
+    }
+/**
+Move past specified number of entries
+
+@param aEntryPos Start position to move from, updated as move takes place
+@param aEntry Directory entry moved to
+@param aToMove Number of entries to move through
+@param aDirEntries Number of entries moved, updated as move takes place
+@leave System wide error code
+*/
+void CScanDrive::MovePastEntriesL(TEntryPos& aEntryPos,TFatDirEntry& aEntry,TInt aToMove,TInt& aDirEntries)
+    {
+    while(aToMove-- && aEntryPos.iCluster!=KEndOfDirectory)
+        {
+        iMount->MoveToNextEntryL(aEntryPos);
+        ++aDirEntries;
+        }
+    iMount->ReadDirEntryL(aEntryPos,aEntry);
+    }
+
+/**
+Adds aCluster to cluster list array so that it may be revisited later, avoids stack 
+over flow
+
+@param aCluster Directory cluster number to add to the list
+@leave KErrNoMemory If allocation fails
+*/
+void CScanDrive::AddToClusterListL(TInt aCluster)
+    {
+    if(iListArrayIndex>=KMaxArrayDepth)
+        return;
+    if(iClusterListArray[iListArrayIndex]==NULL)
+        iClusterListArray[iListArrayIndex]=new(ELeave) RArray<TInt>(KClusterListGranularity);
+    iClusterListArray[iListArrayIndex]->Append(aCluster);
+    }
+
+
+#if defined(DEBUG_SCANDRIVE)
+void CScanDrive::CompareFatsL()
+//
+// Compare new fat and first fat table
+//  
+    {
+    __PRINT(_L("CScanDrive::CompareFatsL()"));
+    TInt maxClusters;
+    maxClusters=iMount->UsableClusters();
+    for(TInt i=KFatFirstSearchCluster; i<maxClusters; ++i)
+        {
+        TInt realFat=iMount->FAT().ReadL(i);
+        TInt newFat=iNewFat->ReadL(i);
+        if(realFat!=newFat)
+            {
+            if(realFat!=0 && newFat==0)
+                __PRINT1(_L("Lost cluster=%d\n"),i)
+            else if((realFat>0 && !IsEofF(realFat)) && IsEofF(newFat))
+                __PRINT1(_L("Hanging cluster = %d\n"),i)
+            else if(realFat==0 && newFat>0)
+                __PRINT1(_L("Unflushed cluster = %d\n"),i)
+            else
+                User::Leave(KErrCorrupt);
+            }
+        }
+    }   
+
+
+/** 
+For debug purposes, print errors found as debug output 
+ 
+*/ 
+void CScanDrive::PrintErrors()
+    {
+    __PRINT1(_L("Directories visisted = %d\n"),iDirsChecked);
+    if(iDirError==EScanPartEntry)
+        __PRINT2(_L("Part entry-dir cluster=%d,dir pos=%d,\n"),iPartEntry.iEntryPos.iCluster,iPartEntry.iEntryPos.iPos)
+    else if(iDirError==EScanMatchingEntry)
+        {
+        __PRINT1(_L("Matching cluster - cluster no=%d\n"),iMatching.iStartCluster);
+        __PRINT2(_L("\tcluster 1 - dir cluster=%d,dir pos=%d\n"),iMatching.iEntries[0].iCluster,iMatching.iEntries[0].iPos);
+        __PRINT2(_L("\tcluster 2 - dir cluster=%d,dir pos=%d\n"),iMatching.iEntries[1].iCluster,iMatching.iEntries[1].iPos);
+        }
+    }
+    
+#endif
+
+
+
+