Leaked source code of windows server 2003
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/*++
Copyright (c) 1998-2002 Microsoft Corporation
Module Name:
filecache.h
Abstract:
This module contains declarations for the open file handle cache.
Author:
Keith Moore (keithmo) 21-Aug-1998
Revision History:
--*/
#ifndef _FILECACHE_H_
#define _FILECACHE_H_
//
// Data used to track a file cache entry.
//
typedef struct _UL_FILE_CACHE_ENTRY
{
//
// Signature.
//
ULONG Signature;
//
// Sector-size information gleaned from the file system.
//
ULONG BytesPerSector;
//
// File-length information gleaned from the file system.
//
LARGE_INTEGER EndOfFile;
//
// A pre-referenced file object pointer for this file. This pointer
// is valid in *any* thread/process context.
//
PFILE_OBJECT pFileObject;
//
// The *correct* device object referenced by the above file object.
//
PDEVICE_OBJECT pDeviceObject;
//
// Fast I/O routines.
//
PFAST_IO_MDL_READ pMdlRead;
PFAST_IO_MDL_READ_COMPLETE pMdlReadComplete;
} UL_FILE_CACHE_ENTRY, *PUL_FILE_CACHE_ENTRY;
#define UL_FILE_CACHE_ENTRY_SIGNATURE MAKE_SIGNATURE('FILE')
#define UL_FILE_CACHE_ENTRY_SIGNATURE_X MAKE_FREE_SIGNATURE(UL_FILE_CACHE_ENTRY_SIGNATURE)
#define IS_VALID_FILE_CACHE_ENTRY( entry ) \
HAS_VALID_SIGNATURE(entry, UL_FILE_CACHE_ENTRY_SIGNATURE)
//
// A file buffer contains the results of a read from a file cache entry.
// The file cache read and read complete routines take pointers to this
// structure. A read fills it in, and a read complete frees the data.
//
typedef struct _UL_FILE_BUFFER
{
//
// The file that provided the data.
//
PUL_FILE_CACHE_ENTRY pFileCacheEntry;
//
// The data read from the file. Filled in by
// the read routines.
//
PMDL pMdl;
//
// If we have to allocate our own buffer to hold file data
// we'll save a pointer to the data buffer here.
//
PUCHAR pFileData;
//
// Information about the data buffers.
// Filled in by the read routine's caller.
//
ULARGE_INTEGER FileOffset;
ULONG RelativeOffset;
ULONG Length;
//
// Completion routine and context information set by the caller.
//
PIO_COMPLETION_ROUTINE pCompletionRoutine;
PVOID pContext;
} UL_FILE_BUFFER, *PUL_FILE_BUFFER;
NTSTATUS
InitializeFileCache(
VOID
);
VOID
TerminateFileCache(
VOID
);
//
// Routines to create, reference and release a cache entry.
//
NTSTATUS
UlCreateFileEntry(
IN HANDLE FileHandle,
IN OUT PUL_FILE_CACHE_ENTRY pFileCacheEntry
);
VOID
UlDestroyFileCacheEntry(
IN PUL_FILE_CACHE_ENTRY pFileCacheEntry
);
//
// Read and read complete routines.
//
// The fast versions complete immediately, but sometimes fail.
// The normal versions use an IRP provided by the caller.
//
NTSTATUS
UlReadFileEntry(
IN OUT PUL_FILE_BUFFER pFileBuffer,
IN PIRP pIrp
);
NTSTATUS
UlReadFileEntryFast(
IN OUT PUL_FILE_BUFFER pFileBuffer
);
NTSTATUS
UlReadCompleteFileEntry(
IN PUL_FILE_BUFFER pFileBuffer,
IN PIRP pIrp
);
NTSTATUS
UlReadCompleteFileEntryFast(
IN PUL_FILE_BUFFER pFileBuffer
);
//
// UL_FILE_BUFFER macros.
//
#define IS_FILE_BUFFER_IN_USE(fbuf) ((fbuf)->pFileCacheEntry)
//
// Dummy MdlRead and MdlReadComplete routines.
//
BOOLEAN
UlFailMdlReadDev(
IN PFILE_OBJECT FileObject,
IN PLARGE_INTEGER FileOffset,
IN ULONG Length,
IN ULONG LockKey,
OUT PMDL *MdlChain,
OUT PIO_STATUS_BLOCK IoStatus,
IN PDEVICE_OBJECT DeviceObject
);
BOOLEAN
UlFailMdlReadCompleteDev(
IN PFILE_OBJECT FileObject,
IN PMDL MdlChain,
IN PDEVICE_OBJECT DeviceObject
);
#endif // _FILECACHE_H_