Leaked source code of windows server 2003
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//+---------------------------------------------------------------------------
//
// Microsoft Windows
// Copyright (C) Microsoft Corporation, 1991 - 1999
//
// File: filidmap.cxx
//
// Contents: FileId to wid mapping using hashed access
//
// History: 07-May-97 SitaramR Created
//
// Notes: Only ntfs 5.0 wids are added to the file id map because all
// non-ntfs 5.0 wids map to fileIdInvalid, which means that there
// will be too many collisions on fileIdInvalid, which will degrade
// the performance of the hashed access. One drawback of mapping
// only ntfs 5.0 wids is that the count of wids in fileid map and
// property store cannot be checked for equality to detect
// corruption as is done for the strings table. However, there is a
// correlation between a count mismatch in strings table and in
// file id map table because the file id map table is flushed before
// the strings table. As a result, when a corruption is detected
// in strings table, a corruption error is thrown and the processing
// for that corruption error reinitializes both strings table and the
// file id map table.
//
//----------------------------------------------------------------------------
#include <pch.cxx>
#pragma hdrstop
#include <filidmap.hxx>
#include <mmstrm.hxx>
#include <cistore.hxx>
#include <prpstmgr.hxx>
#include <propiter.hxx>
#include <cicat.hxx>
//+---------------------------------------------------------------------------
//
// Member: CFileIdMap::CFileIdMap
//
// Synopsis: Constructor
//
// Arguments: [propStoreMgr] -- Property store
// [cicat] -- CiCat
//
// History: 07-May-97 SitaramR Created
//
//----------------------------------------------------------------------------
CFileIdMap::CFileIdMap( CPropStoreManager &propStoreMgr )
: CPersHash( propStoreMgr, FALSE ),
_cCacheEntries( 0 )
#if CIDBG == 1
, _cCacheHits( 0 ),
_cCacheNegativeHits( 0 ),
_cCacheMisses( 0 ),
_cCacheNegativeMisses( 0 )
#endif
{
}
//+---------------------------------------------------------------------------
//
// Member: CFileIdMap::FastInit
//
// Synopsis: Fast initialization
//
// Arguments: [pStorage] -- Ci storage
// [pwcsCatDir] -- Catalog directory
// [pwcsFile] -- File id file name
// [version] -- Content index version
//
// History: 28-Jul-97 SitaramR Created
// 13-Mar-98 KitmanH Passed in True to
// CPerHash::FastInit to specify
// that a FileIdMap is wanted
//
//----------------------------------------------------------------------------
BOOL CFileIdMap::FastInit( CiStorage * pStorage,
ULONG version )
{
return CPersHash::FastInit(pStorage, version, TRUE);
}
//+---------------------------------------------------------------------------
//
// Member: CFileIdMap::LongInit
//
// Synopsis: Initialization that may take a long time
//
// Arguments: [version] -- CI version
// [fDirtyShutdown] -- Set to TRUE if the previous shutdown
// was dirty.
//
// History: 28-Jul-97 SitaramR Created
//
//----------------------------------------------------------------------------
void CFileIdMap::LongInit ( ULONG version, BOOL fDirtyShutdown )
{
CPersHash::LongInit( version, fDirtyShutdown );
}
//+---------------------------------------------------------------------------
//
// Member: CFileIdMap::LokFlush
//
// Synopsis: Flushes fileid map
//
// History: 28-Jul-97 SitaramR Created
// 27-Feb-98 KitmanH Don't flush if catalog is
// read-only
//
//----------------------------------------------------------------------------
void CFileIdMap::LokFlush()
{
if ( !_fIsReadOnly )
CPersHash::LokFlush();
} //LokFlush
//+-------------------------------------------------------------------------
//
// Member: CFileIdMap::AddToCache, private
//
// Synopsis: Adds an entry to the cache, or overwrites wid if the
// entry currently exists. The oldest entry is bumped out.
// Caching an entry with widInvalid is valid.
//
// Arguments: [fileId] -- FileId to add
// [wid] -- VolumeId to add
// [volumeId] -- VolumeId to add
//
// History: 22-Jul-98 dlee Created
//
//--------------------------------------------------------------------------
void CFileIdMap::AddToCache(
FILEID & fileId,
WORKID wid,
VOLUMEID volumeId )
{
// First look for the fileid/volumeid currently in the cache
for ( unsigned iCache = 0; iCache < _cCacheEntries; iCache++ )
{
if ( _aCache[ iCache ].fileId == fileId &&
_aCache[ iCache ].volumeId == volumeId )
{
_aCache[ iCache ].wid = wid;
return;
}
}
Win4Assert( _cCacheEntries <= cFileIdMapCacheEntries );
// Bump out the oldest item and put the new item first in the array
unsigned cToMove;
if ( _cCacheEntries == cFileIdMapCacheEntries )
{
cToMove = cFileIdMapCacheEntries - 1;
}
else
{
cToMove = _cCacheEntries;
_cCacheEntries++;
}
RtlMoveMemory( & _aCache[ 1 ],
& _aCache[ 0 ],
sizeof SFileIdMapEntry * cToMove );
_aCache[0].fileId = fileId;
_aCache[0].volumeId = volumeId;
_aCache[0].wid = wid;
} //AddToCache
//+-------------------------------------------------------------------------
//
// Member: CFileIdMap::FindInCache, private
//
// Synopsis: Locates a workid in the cache given a fileid and volumeid
//
// Arguments: [fileId] -- FileId of entry to find
// [volumeId] -- VolumeId of entry to find
// [wid] -- Returns the workid if found
//
// Returns: TRUE if found or FALSE if not found
//
// History: 22-Jul-98 dlee Created
//
//--------------------------------------------------------------------------
BOOL CFileIdMap::FindInCache(
FILEID & fileId,
VOLUMEID volumeId,
WORKID & wid )
{
for ( unsigned iCache = 0; iCache < _cCacheEntries; iCache++ )
{
if ( _aCache[ iCache ].fileId == fileId &&
_aCache[ iCache ].volumeId == volumeId )
{
wid = _aCache[ iCache ].wid;
#if CIDBG == 1
ciDebugOut(( DEB_USN,
"fim::find cache worked %#I64x %#x, vol %wc\n",
fileId, wid, volumeId ));
_cCacheHits++;
if ( widInvalid == wid )
_cCacheNegativeHits++;
#endif
return TRUE;
}
}
return FALSE;
} //FindInCache
//+-------------------------------------------------------------------------
//
// Member: CFileIdMap::RemoveFromCache, private
//
// Synopsis: Removes the item from the cache if it exists
//
// Arguments: [fileId] -- FileId of entry to remove (only used for assert)
// [wid] -- Workid of entry to remove
//
// History: 22-Jul-98 dlee Created
//
//--------------------------------------------------------------------------
void CFileIdMap::RemoveFromCache(
FILEID & fileId,
WORKID wid )
{
for ( unsigned iCache = 0; iCache < _cCacheEntries; iCache++ )
{
if ( _aCache[ iCache ].wid == wid )
{
Win4Assert( _aCache[ iCache ].fileId == fileId );
RtlCopyMemory( & _aCache[ iCache ],
& _aCache[ iCache + 1 ],
sizeof SFileIdMapEntry * ( _cCacheEntries - iCache - 1 ) );
_cCacheEntries--;
break;
}
}
} //RemoveFromCache
//+-------------------------------------------------------------------------
//
// Member: CFileIdMap::LokFind, private
//
// Synopsis: Given fileId, find workid.
//
// Arguments: [fileId] - FileId to locate
// [volumeId] - Volume id of fileid
//
// Returns: Workid of FileId
//
// History: 07-May-97 SitaramR Created
//
// Notes: File ids are not unique across different volumes, hence the
// need for volume ids.
//
//--------------------------------------------------------------------------
WORKID CFileIdMap::LokFind( FILEID fileId, VOLUMEID volumeId )
{
Win4Assert( _fFullInit );
WORKID wid;
if ( FindInCache( fileId, volumeId, wid ) )
return wid;
#if CIDBG == 1
_cCacheMisses++;
#endif
#ifdef DO_STATS
unsigned cSearchLen = 0;
#endif
CShortWidList list( HashFun(fileId), _hTable );
for ( wid = list.WorkId(); wid != widInvalid; wid = list.NextWorkId() )
{
#ifdef DO_STATS
cSearchLen++;
#endif
XPrimaryRecord rec( _PropStoreMgr, wid );
PROPVARIANT propVar;
BOOL fFound = _PropStoreMgr.ReadProperty( rec.GetReference(),
pidFileIndex,
propVar );
ciDebugOut(( DEB_ITRACE, "trying wid %#x, fFound %d, fid %#I64x\n",
wid, fFound, propVar.uhVal.QuadPart ));
if ( fFound && propVar.uhVal.QuadPart == fileId )
{
Win4Assert( propVar.vt == VT_UI8 );
BOOL fFound = _PropStoreMgr.ReadProperty( rec.GetReference(),
pidVolumeId,
propVar );
if ( fFound && propVar.ulVal == volumeId )
{
Win4Assert( propVar.vt == VT_UI4 );
#ifdef DO_STATS
_hTable.UpdateStats( cSearchLen );
#endif
ciDebugOut(( DEB_USN, "fim::find worked %#I64x %#x, vol %wc\n",
fileId, wid, volumeId ));
AddToCache( fileId, wid, volumeId );
return wid;
}
else
{
ciDebugOut(( DEB_USN, "fim::find fileid match, but not volid: %#x, %#x\n",
propVar.ulVal, volumeId ));
}
}
}
ciDebugOut(( DEB_USN, "fim::find failed %#I64x, vol %wc\n", fileId, volumeId ));
#if CIDBG == 1
_cCacheNegativeMisses++;
#endif
//
// Often, a new file is looked up multiple times before it is added, so
// add the widInvalid entry to the cache. Negative lookups are slow.
//
AddToCache( fileId, widInvalid, volumeId );
return widInvalid;
} //LokFind
//+-------------------------------------------------------------------------
//
// Member: CFileIdMap::LokAdd
//
// Synopsis: Add a new fileid to wid mapping
//
// Arguments: [fileId] -- File Id
// [wid] -- Workid
//
// History: 07-May-97 SitaramR Created
//
//--------------------------------------------------------------------------
void CFileIdMap::LokAdd( FILEID fileId, WORKID wid, VOLUMEID volumeId )
{
ciDebugOut(( DEB_USN, "Adding map fileid %#I64x -> wid %x, vol %wc\n",
fileId, wid, volumeId ));
Win4Assert( fileIdInvalid != fileId );
Win4Assert( _fFullInit );
//
// Must grow hash table first, as it grovels through property store.
//
if ( _hTable.IsFull() )
GrowHashTable();
AddToCache( fileId, wid, volumeId );
_hTable.Add ( HashFun(fileId), wid );
} //LokAdd
//+---------------------------------------------------------------------------
//
// Member: CFileIdMap::LokDelete
//
// Synopsis: Delete file id from table
//
// Arguments: [fileId] -- FileId to remove
// [wid] -- Workid to remove
//
// History: 07-May-97 SitaramR Created.
//
//----------------------------------------------------------------------------
void CFileIdMap::LokDelete( FILEID fileId, WORKID wid )
{
ciDebugOut(( DEB_USN, "Removing map fileid %#I64x, %#x\n", fileId, wid ));
RemoveFromCache( fileId, wid );
_hTable.Remove( HashFun( fileId ), wid, TRUE );
} //LokDelete
//+---------------------------------------------------------------------------
//
// Member: CFileIdMap::HashAll
//
// Synopsis: Re-hash all fileId's (after hash table growth)
//
// History: 07-May-97 May Created
//
//----------------------------------------------------------------------------
void CFileIdMap::HashAll()
{
// Count the number of hash table entries and grow the hash table
{
CPropertyStoreWids iter( _PropStoreMgr );
unsigned cWids = 0;
for ( WORKID wid = iter.WorkId(); wid != widInvalid; wid = iter.NextWorkId() )
{
if ( _fAbort )
{
ciDebugOut(( DEB_WARN,
"Stopping FileIdMap::HashAll because of shutdown\n" ));
THROW( CException(STATUS_TOO_LATE) );
}
PROPVARIANT propVar;
BOOL fFound = _PropStoreMgr.ReadPrimaryProperty( wid, pidFileIndex, propVar );
// Only ntfs 5.0 wids have valid fileid's
if ( fFound &&
( VT_UI8 == propVar.vt ) &&
( fileIdInvalid != propVar.uhVal.QuadPart ) )
cWids++;
}
GrowToSize( cWids );
}
// Add the wids to the hash table
CPropertyStoreWids iter( _PropStoreMgr );
for ( WORKID wid = iter.WorkId(); wid != widInvalid; wid = iter.NextWorkId() )
{
if ( _fAbort )
{
ciDebugOut(( DEB_WARN,
"Stopping FileIdMap::HashAll because of shutdown\n" ));
THROW( CException(STATUS_TOO_LATE) );
}
PROPVARIANT propVar;
BOOL fFound = _PropStoreMgr.ReadPrimaryProperty( wid, pidFileIndex, propVar );
//
// Only ntfs 5.0 wids have valid fileid's
//
if ( fFound &&
( VT_UI8 == propVar.vt ) &&
( fileIdInvalid != propVar.uhVal.QuadPart ) )
_hTable.Add ( HashFun( propVar.uhVal.QuadPart ), wid );
}
#if 0
//
// Look-up every file to see what the hashing looks like.
//
{
CPropertyStoreWids iter( _PropStoreMgr );
unsigned cWids = 0;
for ( WORKID wid = iter.WorkId(); wid != widInvalid; wid = iter.NextWorkId() )
{
XPrimaryRecord rec( _PropStoreMgr, wid );
PROPVARIANT propVar;
BOOL fFound = _PropStoreMgr.ReadProperty( rec.GetReference(),
pidFileIndex,
propVar );
// Only ntfs 5.0 wids have valid fileid's
if ( fFound &&
( VT_UI8 == propVar.vt ) &&
( fileIdInvalid != propVar.uhVal.QuadPart ) )
{
FILEID fid = propVar.uhVal.QuadPart;
_PropStoreMgr.ReadProperty( rec.GetReference(),
pidVolumeId,
propVar );
LokFind( fid, propVar.ulVal );
}
}
ciDebugOut(( DEB_FORCE,
"hash: size %d count %d maxchain %d searches %d length %d\n",
_hTable.Size(),
_hTable.Count(),
_hTable._cMaxChainLen,
_hTable._cTotalSearches,
_hTable._cTotalLength ));
}
#endif
} //HashAll
//+-------------------------------------------------------------------------
//
// Member: CFileIdMap::HashFun
//
// Synopsis: Hash function for fileid's
//
// Arguments: [fileId] - FileId to hash
//
// History: 07-May-97 SitaramR Created
//
//--------------------------------------------------------------------------
unsigned CFileIdMap::HashFun( FILEID fileId )
{
//
// The lower 32 bits of the fileid are unique at any given time. The
// upper 32 bits of the fileid represent a sequence number that is
// incremented every time one of the lower 32 bits number is reused.
// So, a good hash function is to simply use the lower 32 bits.
//
return (unsigned) fileId;
} //HashFun