windows-server-2003/base/ntos/inc/fsrtl.h

/*++ BUILD Version: 0001    // Increment this if a change has global effects

Copyright (c) 1989  Microsoft Corporation

Module Name:

    FsRtl.h

Abstract:

    This module defines all of the general File System Rtl routines

Author:

    Gary Kimura     [GaryKi]    30-Jul-1990

Revision History:

--*/

#ifndef _FSRTL_
#define _FSRTL_

// begin_ntifs
//
//  The following are globally used definitions for an LBN and a VBN
//

typedef ULONG LBN;
typedef LBN *PLBN;

typedef ULONG VBN;
typedef VBN *PVBN;


// end_ntifs
//
//  The following routine is called during phase 1 initialization to allow
//  us to create the pool of file system threads and the associated
//  synchronization resources.
//

NTKERNELAPI
BOOLEAN
FsRtlInitSystem (
    );

// begin_ntifs
//
//  Every file system that uses the cache manager must have FsContext
//  of the file object point to a common fcb header structure.
// end_ntifs
//  Either the normal or advanced FsRtl Header.
// begin_ntifs
//

typedef enum _FAST_IO_POSSIBLE {
    FastIoIsNotPossible = 0,
    FastIoIsPossible,
    FastIoIsQuestionable
} FAST_IO_POSSIBLE;

// end_ntifs
//  Changes to this structure will affect FSRTL_ADVANCED_FCB_HEADER.
// begin_ntifs

typedef struct _FSRTL_COMMON_FCB_HEADER {

    CSHORT NodeTypeCode;
    CSHORT NodeByteSize;

    //
    //  General flags available to FsRtl.
    //

    UCHAR Flags;

    //
    //  Indicates if fast I/O is possible or if we should be calling
    //  the check for fast I/O routine which is found via the driver
    //  object.
    //

    UCHAR IsFastIoPossible; // really type FAST_IO_POSSIBLE

    //
    //  Second Flags Field
    //

    UCHAR Flags2;

    //
    //  The following reserved field should always be 0
    //

    UCHAR Reserved;

    PERESOURCE Resource;

    PERESOURCE PagingIoResource;

    LARGE_INTEGER AllocationSize;
    LARGE_INTEGER FileSize;
    LARGE_INTEGER ValidDataLength;

} FSRTL_COMMON_FCB_HEADER;
typedef FSRTL_COMMON_FCB_HEADER *PFSRTL_COMMON_FCB_HEADER;

//
//  This Fcb header is used for files which support caching
//  of compressed data, and related new support.
//
//  We start out by prefixing this structure with the normal
//  FsRtl header from above, which we have to do two different
//  ways for c++ or c.
//

#ifdef __cplusplus
typedef struct _FSRTL_ADVANCED_FCB_HEADER:FSRTL_COMMON_FCB_HEADER {
#else   // __cplusplus

typedef struct _FSRTL_ADVANCED_FCB_HEADER {

    //
    //  Put in the standard FsRtl header fields
    //

    FSRTL_COMMON_FCB_HEADER ;

#endif  // __cplusplus

    //
    //  The following two fields are supported only if
    //  Flags2 contains FSRTL_FLAG2_SUPPORTS_FILTER_CONTEXTS
    //

    //
    //  This is a pointer to a Fast Mutex which may be used to
    //  properly synchronize access to the FsRtl header.  The
    //  Fast Mutex must be nonpaged.
    //

    PFAST_MUTEX FastMutex;

    //
    // This is a pointer to a list of context structures belonging to
    // filesystem filter drivers that are linked above the filesystem.
    // Each structure is headed by FSRTL_FILTER_CONTEXT.
    //

    LIST_ENTRY FilterContexts;

} FSRTL_ADVANCED_FCB_HEADER;
typedef FSRTL_ADVANCED_FCB_HEADER *PFSRTL_ADVANCED_FCB_HEADER;

//
//  Define FsRtl common header flags
//

#define FSRTL_FLAG_FILE_MODIFIED        (0x01)
#define FSRTL_FLAG_FILE_LENGTH_CHANGED  (0x02)
#define FSRTL_FLAG_LIMIT_MODIFIED_PAGES (0x04)

//
//  Following flags determine how the modified page writer should
//  acquire the file.  These flags can't change while either resource
//  is acquired.  If neither of these flags is set then the
//  modified/mapped page writer will attempt to acquire the paging io
//  resource shared.
//

#define FSRTL_FLAG_ACQUIRE_MAIN_RSRC_EX (0x08)
#define FSRTL_FLAG_ACQUIRE_MAIN_RSRC_SH (0x10)

//
//  This flag will be set by the Cache Manager if a view is mapped
//  to a file.
//

#define FSRTL_FLAG_USER_MAPPED_FILE     (0x20)

//  This flag indicates that the file system is using the 
//  FSRTL_ADVANCED_FCB_HEADER structure instead of the FSRTL_COMMON_FCB_HEADER
//  structure.
//

#define FSRTL_FLAG_ADVANCED_HEADER      (0x40)

//  This flag determines whether there currently is an Eof advance
//  in progress.  All such advances must be serialized.
//

#define FSRTL_FLAG_EOF_ADVANCE_ACTIVE   (0x80)

//
//  Flag values for Flags2
//
//  All unused bits are reserved and should NOT be modified.
//

//
//  If this flag is set, the Cache Manager will allow modified writing
//  in spite of the value of FsContext2.
//

#define FSRTL_FLAG2_DO_MODIFIED_WRITE        (0x01)

//
//  If this flag is set, the additional fields FilterContexts and FastMutex
//  are supported in FSRTL_COMMON_HEADER, and can be used to associate
//  context for filesystem filters with streams.
//

#define FSRTL_FLAG2_SUPPORTS_FILTER_CONTEXTS  (0x02)

//
//  If this flag is set, the cache manager will flush and purge the cache map when
//  a user first maps a file
//

#define FSRTL_FLAG2_PURGE_WHEN_MAPPED (0x04)

//
//  The following constants are used to block top level Irp processing when
//  (in either the fast io or cc case) file system resources have been
//  acquired above the file system, or we are in an Fsp thread.
//

#define FSRTL_FSP_TOP_LEVEL_IRP         0x01
#define FSRTL_CACHE_TOP_LEVEL_IRP       0x02
#define FSRTL_MOD_WRITE_TOP_LEVEL_IRP   0x03
#define FSRTL_FAST_IO_TOP_LEVEL_IRP     0x04
#define FSRTL_MAX_TOP_LEVEL_IRP_FLAG    0xFFFF

//
//  The following structure is used to synchronize Eof extends.
//

typedef struct _EOF_WAIT_BLOCK {

    LIST_ENTRY EofWaitLinks;
    KEVENT Event;

} EOF_WAIT_BLOCK;

typedef EOF_WAIT_BLOCK *PEOF_WAIT_BLOCK;

// begin_ntosp
//
//  Normal uncompressed Copy and Mdl Apis
//

NTKERNELAPI
BOOLEAN
FsRtlCopyRead (
    IN PFILE_OBJECT FileObject,
    IN PLARGE_INTEGER FileOffset,
    IN ULONG Length,
    IN BOOLEAN Wait,
    IN ULONG LockKey,
    OUT PVOID Buffer,
    OUT PIO_STATUS_BLOCK IoStatus,
    IN PDEVICE_OBJECT DeviceObject
    );

NTKERNELAPI
BOOLEAN
FsRtlCopyWrite (
    IN PFILE_OBJECT FileObject,
    IN PLARGE_INTEGER FileOffset,
    IN ULONG Length,
    IN BOOLEAN Wait,
    IN ULONG LockKey,
    IN PVOID Buffer,
    OUT PIO_STATUS_BLOCK IoStatus,
    IN PDEVICE_OBJECT DeviceObject
    );

// end_ntifs

NTKERNELAPI
BOOLEAN
FsRtlMdlRead (
    IN PFILE_OBJECT FileObject,
    IN PLARGE_INTEGER FileOffset,
    IN ULONG Length,
    IN ULONG LockKey,
    OUT PMDL *MdlChain,
    OUT PIO_STATUS_BLOCK IoStatus
    );

BOOLEAN
FsRtlMdlReadComplete (
    IN PFILE_OBJECT FileObject,
    IN PMDL MdlChain
    );

// end_ntosp

NTKERNELAPI
BOOLEAN
FsRtlPrepareMdlWrite (
    IN PFILE_OBJECT FileObject,
    IN PLARGE_INTEGER FileOffset,
    IN ULONG Length,
    IN ULONG LockKey,
    OUT PMDL *MdlChain,
    OUT PIO_STATUS_BLOCK IoStatus
    );

BOOLEAN
FsRtlMdlWriteComplete (
    IN PFILE_OBJECT FileObject,
    IN PLARGE_INTEGER FileOffset,
    IN PMDL MdlChain
    );

// begin_ntifs

NTKERNELAPI
BOOLEAN
FsRtlMdlReadDev (
    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
    );

NTKERNELAPI
BOOLEAN
FsRtlMdlReadCompleteDev (
    IN PFILE_OBJECT FileObject,
    IN PMDL MdlChain,
    IN PDEVICE_OBJECT DeviceObject
    );

NTKERNELAPI
BOOLEAN
FsRtlPrepareMdlWriteDev (
    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
    );

NTKERNELAPI
BOOLEAN
FsRtlMdlWriteCompleteDev (
    IN PFILE_OBJECT FileObject,
    IN PLARGE_INTEGER FileOffset,
    IN PMDL MdlChain,
    IN PDEVICE_OBJECT DeviceObject
    );

//
//  In Irps, compressed reads and writes are  designated by the
//  subfunction IRP_MN_COMPRESSED must be set and the Compressed
//  Data Info buffer must be described by the following structure
//  pointed to by Irp->Tail.Overlay.AuxiliaryBuffer.
//

typedef struct _FSRTL_AUXILIARY_BUFFER {

    //
    //  Buffer description with length.
    //

    PVOID Buffer;
    ULONG Length;

    //
    //  Flags
    //

    ULONG Flags;

    //
    //  Pointer to optional Mdl mapping buffer for file system use
    //

    PMDL Mdl;

} FSRTL_AUXILIARY_BUFFER;
typedef FSRTL_AUXILIARY_BUFFER *PFSRTL_AUXILIARY_BUFFER;

//
//  If this flag is set, the auxiliary buffer structure is
//  deallocated on Irp completion.  The caller has the
//  option in this case of appending this structure to the
//  structure being described, causing it all to be
//  deallocated at once.  If this flag is clear, no deallocate
//  occurs.
//

#define FSRTL_AUXILIARY_FLAG_DEALLOCATE 0x00000001

// end_ntifs
//
//  The following routines are intended to be called by Mm to avoid deadlocks.
//  They prerequire file system resources before acquire Mm resources.
//

//
//  This macro is called once when the ModifiedPageWriter is started.
//

#define FsRtlSetTopLevelIrpForModWriter() {             \
    PIRP tempIrp = (PIRP)FSRTL_MOD_WRITE_TOP_LEVEL_IRP; \
    IoSetTopLevelIrp(tempIrp);                          \
}

NTKERNELAPI
BOOLEAN
FsRtlAcquireFileForModWrite (
    IN PFILE_OBJECT FileObject,
    IN PLARGE_INTEGER EndingOffset,
    OUT PERESOURCE *ResourceToRelease
    );

NTKERNELAPI
NTSTATUS
FsRtlAcquireFileForModWriteEx (
    IN PFILE_OBJECT FileObject,
    IN PLARGE_INTEGER EndingOffset,
    OUT PERESOURCE *ResourceToRelease
    );

NTKERNELAPI
VOID
FsRtlReleaseFileForModWrite (
    IN PFILE_OBJECT FileObject,
    IN PERESOURCE ResourceToRelease
    );

NTKERNELAPI
VOID
FsRtlAcquireFileForCcFlush (
    IN PFILE_OBJECT FileObject
    );

NTKERNELAPI
NTSTATUS
FsRtlAcquireFileForCcFlushEx (
    IN PFILE_OBJECT FileObject
    );

NTKERNELAPI
VOID
FsRtlReleaseFileForCcFlush (
    IN PFILE_OBJECT FileObject
    );

NTKERNELAPI
NTSTATUS
FsRtlAcquireToCreateMappedSection (
    IN PFILE_OBJECT FileObject,
    IN ULONG SectionPageProtection
    );
    
NTKERNELAPI
NTSTATUS
FsRtlAcquireFileExclusiveCommon (
    IN PFILE_OBJECT FileObject,
    IN FS_FILTER_SECTION_SYNC_TYPE SyncType,
    IN ULONG SectionPageProtection
    );

// begin_ntifs
//
//  The following two routines are called from NtCreateSection to avoid
//  deadlocks with the file systems.
//

NTKERNELAPI
VOID
FsRtlAcquireFileExclusive (
    IN PFILE_OBJECT FileObject
    );

NTKERNELAPI
VOID
FsRtlReleaseFile (
    IN PFILE_OBJECT FileObject
    );

//
//  These routines provide a simple interface for the common operations
//  of query/set file size.
//

NTSTATUS
FsRtlGetFileSize(
    IN PFILE_OBJECT FileObject,
    IN OUT PLARGE_INTEGER FileSize
    );

// end_ntifs

NTSTATUS
FsRtlSetFileSize(
    IN PFILE_OBJECT FileObject,
    IN OUT PLARGE_INTEGER FileSize
    );

// begin_ntddk begin_ntifs
//
// Determine if there is a complete device failure on an error.
//

NTKERNELAPI
BOOLEAN
FsRtlIsTotalDeviceFailure(
    IN NTSTATUS Status
    );

// end_ntddk

//
//  Byte range file lock routines, implemented in FileLock.c
//
//  The file lock info record is used to return enumerated information
//  about a file lock
//

typedef struct _FILE_LOCK_INFO {

    //
    //  A description of the current locked range, and if the lock
    //  is exclusive or shared
    //

    LARGE_INTEGER StartingByte;
    LARGE_INTEGER Length;
    BOOLEAN ExclusiveLock;

    //
    //  The following fields describe the owner of the lock.
    //

    ULONG Key;
    PFILE_OBJECT FileObject;
    PVOID ProcessId;

    //
    //  The following field is used internally by FsRtl
    //

    LARGE_INTEGER EndingByte;

} FILE_LOCK_INFO;
typedef FILE_LOCK_INFO *PFILE_LOCK_INFO;

//
//  The following two procedure prototypes are used by the caller of the
//  file lock package to supply an alternate routine to call when
//  completing an IRP and when unlocking a byte range.  Note that the only
//  utility to us this interface is currently the redirector, all other file
//  system will probably let the IRP complete normally with IoCompleteRequest.
//  The user supplied routine returns any value other than success then the
//  lock package will remove any lock that we just inserted.
//

typedef NTSTATUS (*PCOMPLETE_LOCK_IRP_ROUTINE) (
    IN PVOID Context,
    IN PIRP Irp
    );

typedef VOID (*PUNLOCK_ROUTINE) (
    IN PVOID Context,
    IN PFILE_LOCK_INFO FileLockInfo
    );

//
//  A FILE_LOCK is an opaque structure but we need to declare the size of
//  it here so that users can allocate space for one.
//

typedef struct _FILE_LOCK {

    //
    //  The optional procedure to call to complete a request
    //

    PCOMPLETE_LOCK_IRP_ROUTINE CompleteLockIrpRoutine;

    //
    //  The optional procedure to call when unlocking a byte range
    //

    PUNLOCK_ROUTINE UnlockRoutine;

    //
    //  FastIoIsQuestionable is set to true whenever the filesystem require
    //  additional checking about whether the fast path can be taken.  As an
    //  example Ntfs requires checking for disk space before the writes can
    //  occur.
    //

    BOOLEAN FastIoIsQuestionable;
    BOOLEAN SpareC[3];

    //
    //  FsRtl lock information
    //

    PVOID   LockInformation;

    //
    //  Contains continuation information for FsRtlGetNextFileLock
    //

    FILE_LOCK_INFO  LastReturnedLockInfo;
    PVOID           LastReturnedLock;

} FILE_LOCK;
typedef FILE_LOCK *PFILE_LOCK;

PFILE_LOCK
FsRtlAllocateFileLock (
    IN PCOMPLETE_LOCK_IRP_ROUTINE CompleteLockIrpRoutine OPTIONAL,
    IN PUNLOCK_ROUTINE UnlockRoutine OPTIONAL
    );

VOID
FsRtlFreeFileLock (
    IN PFILE_LOCK FileLock
    );

NTKERNELAPI
VOID
FsRtlInitializeFileLock (
    IN PFILE_LOCK FileLock,
    IN PCOMPLETE_LOCK_IRP_ROUTINE CompleteLockIrpRoutine OPTIONAL,
    IN PUNLOCK_ROUTINE UnlockRoutine OPTIONAL
    );

NTKERNELAPI
VOID
FsRtlUninitializeFileLock (
    IN PFILE_LOCK FileLock
    );

NTKERNELAPI
NTSTATUS
FsRtlProcessFileLock (
    IN PFILE_LOCK FileLock,
    IN PIRP Irp,
    IN PVOID Context OPTIONAL
    );

NTKERNELAPI
BOOLEAN
FsRtlCheckLockForReadAccess (
    IN PFILE_LOCK FileLock,
    IN PIRP Irp
    );

NTKERNELAPI
BOOLEAN
FsRtlCheckLockForWriteAccess (
    IN PFILE_LOCK FileLock,
    IN PIRP Irp
    );

NTKERNELAPI
BOOLEAN
FsRtlFastCheckLockForRead (
    IN PFILE_LOCK FileLock,
    IN PLARGE_INTEGER StartingByte,
    IN PLARGE_INTEGER Length,
    IN ULONG Key,
    IN PFILE_OBJECT FileObject,
    IN PVOID ProcessId
    );

NTKERNELAPI
BOOLEAN
FsRtlFastCheckLockForWrite (
    IN PFILE_LOCK FileLock,
    IN PLARGE_INTEGER StartingByte,
    IN PLARGE_INTEGER Length,
    IN ULONG Key,
    IN PVOID FileObject,
    IN PVOID ProcessId
    );

NTKERNELAPI
PFILE_LOCK_INFO
FsRtlGetNextFileLock (
    IN PFILE_LOCK FileLock,
    IN BOOLEAN Restart
    );

NTKERNELAPI
NTSTATUS
FsRtlFastUnlockSingle (
    IN PFILE_LOCK FileLock,
    IN PFILE_OBJECT FileObject,
    IN LARGE_INTEGER UNALIGNED *FileOffset,
    IN PLARGE_INTEGER Length,
    IN PEPROCESS ProcessId,
    IN ULONG Key,
    IN PVOID Context OPTIONAL,
    IN BOOLEAN AlreadySynchronized
    );

NTKERNELAPI
NTSTATUS
FsRtlFastUnlockAll (
    IN PFILE_LOCK FileLock,
    IN PFILE_OBJECT FileObject,
    IN PEPROCESS ProcessId,
    IN PVOID Context OPTIONAL
    );

NTKERNELAPI
NTSTATUS
FsRtlFastUnlockAllByKey (
    IN PFILE_LOCK FileLock,
    IN PFILE_OBJECT FileObject,
    IN PEPROCESS ProcessId,
    IN ULONG Key,
    IN PVOID Context OPTIONAL
    );

NTKERNELAPI
BOOLEAN
FsRtlPrivateLock (
    IN PFILE_LOCK FileLock,
    IN PFILE_OBJECT FileObject,
    IN PLARGE_INTEGER FileOffset,
    IN PLARGE_INTEGER Length,
    IN PEPROCESS ProcessId,
    IN ULONG Key,
    IN BOOLEAN FailImmediately,
    IN BOOLEAN ExclusiveLock,
    OUT PIO_STATUS_BLOCK Iosb,
    IN PIRP Irp,
    IN PVOID Context,
    IN BOOLEAN AlreadySynchronized
    );

//
//  BOOLEAN
//  FsRtlFastLock (
//      IN PFILE_LOCK FileLock,
//      IN PFILE_OBJECT FileObject,
//      IN PLARGE_INTEGER FileOffset,
//      IN PLARGE_INTEGER Length,
//      IN PEPROCESS ProcessId,
//      IN ULONG Key,
//      IN BOOLEAN FailImmediately,
//      IN BOOLEAN ExclusiveLock,
//      OUT PIO_STATUS_BLOCK Iosb,
//      IN PVOID Context OPTIONAL,
//      IN BOOLEAN AlreadySynchronized
//      );
//

#define FsRtlFastLock(A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11) ( \
    FsRtlPrivateLock( A1,   /* FileLock            */       \
                      A2,   /* FileObject          */       \
                      A3,   /* FileOffset          */       \
                      A4,   /* Length              */       \
                      A5,   /* ProcessId           */       \
                      A6,   /* Key                 */       \
                      A7,   /* FailImmediately     */       \
                      A8,   /* ExclusiveLock       */       \
                      A9,   /* Iosb                */       \
                      NULL, /* Irp                 */       \
                      A10,  /* Context             */       \
                      A11   /* AlreadySynchronized */ )     \
)

//
//  BOOLEAN
//  FsRtlAreThereCurrentFileLocks (
//      IN PFILE_LOCK FileLock
//      );
//

#define FsRtlAreThereCurrentFileLocks(FL) ( \
    ((FL)->FastIoIsQuestionable))



//
//  Filesystem property tunneling, implemented in tunnel.c
//

//
//  Tunnel cache structure
//

typedef struct {

    //
    //  Mutex for cache manipulation
    //

    FAST_MUTEX          Mutex;

    //
    //  Splay Tree of tunneled information keyed by
    //  DirKey ## Name
    //

    PRTL_SPLAY_LINKS    Cache;

    //
    //  Timer queue used to age entries out of the main cache
    //

    LIST_ENTRY          TimerQueue;

    //
    //  Keep track of the number of entries in the cache to prevent
    //  excessive use of memory
    //

    USHORT              NumEntries;

} TUNNEL, *PTUNNEL;

NTKERNELAPI
VOID
FsRtlInitializeTunnelCache (
    IN TUNNEL *Cache);

NTKERNELAPI
VOID
FsRtlAddToTunnelCache (
    IN TUNNEL *Cache,
    IN ULONGLONG DirectoryKey,
    IN UNICODE_STRING *ShortName,
    IN UNICODE_STRING *LongName,
    IN BOOLEAN KeyByShortName,
    IN ULONG DataLength,
    IN VOID *Data);

NTKERNELAPI
BOOLEAN
FsRtlFindInTunnelCache (
    IN TUNNEL *Cache,
    IN ULONGLONG DirectoryKey,
    IN UNICODE_STRING *Name,
    OUT UNICODE_STRING *ShortName,
    OUT UNICODE_STRING *LongName,
    IN OUT ULONG  *DataLength,
    OUT VOID *Data);


NTKERNELAPI
VOID
FsRtlDeleteKeyFromTunnelCache (
    IN TUNNEL *Cache,
    IN ULONGLONG DirectoryKey);


NTKERNELAPI
VOID
FsRtlDeleteTunnelCache (
    IN TUNNEL *Cache);


//
//  Dbcs name support routines, implemented in DbcsName.c
//

//
//  The following enumerated type is used to denote the result of name
//  comparisons
//

typedef enum _FSRTL_COMPARISON_RESULT {
    LessThan = -1,
    EqualTo = 0,
    GreaterThan = 1
} FSRTL_COMPARISON_RESULT;

#ifdef NLS_MB_CODE_PAGE_TAG
#undef NLS_MB_CODE_PAGE_TAG
#endif // NLS_MB_CODE_PAGE_TAG

// end_ntifs
#if defined(_NTIFS_) || defined(_NTDRIVER_)
// begin_ntifs

#define LEGAL_ANSI_CHARACTER_ARRAY        (*FsRtlLegalAnsiCharacterArray) // ntosp
#define NLS_MB_CODE_PAGE_TAG              (*NlsMbOemCodePageTag)
#define NLS_OEM_LEAD_BYTE_INFO            (*NlsOemLeadByteInfo) // ntosp

// end_ntifs
#else

#define LEGAL_ANSI_CHARACTER_ARRAY        FsRtlLegalAnsiCharacterArray
#define NLS_MB_CODE_PAGE_TAG              NlsMbOemCodePageTag
#define NLS_OEM_LEAD_BYTE_INFO            NlsOemLeadByteInfo

#endif
// begin_ntifs begin_ntosp

extern UCHAR const* const LEGAL_ANSI_CHARACTER_ARRAY;
extern PUSHORT NLS_OEM_LEAD_BYTE_INFO;  // Lead byte info. for ACP

//
//  These following bit values are set in the FsRtlLegalDbcsCharacterArray
//

#define FSRTL_FAT_LEGAL         0x01
#define FSRTL_HPFS_LEGAL        0x02
#define FSRTL_NTFS_LEGAL        0x04
#define FSRTL_WILD_CHARACTER    0x08
#define FSRTL_OLE_LEGAL         0x10
#define FSRTL_NTFS_STREAM_LEGAL (FSRTL_NTFS_LEGAL | FSRTL_OLE_LEGAL)

//
//  The following macro is used to determine if an Ansi character is wild.
//

#define FsRtlIsAnsiCharacterWild(C) (                               \
    FsRtlTestAnsiCharacter((C), FALSE, FALSE, FSRTL_WILD_CHARACTER) \
)

//
//  The following macro is used to determine if an Ansi character is Fat legal.
//

#define FsRtlIsAnsiCharacterLegalFat(C,WILD_OK) (                 \
    FsRtlTestAnsiCharacter((C), TRUE, (WILD_OK), FSRTL_FAT_LEGAL) \
)

//
//  The following macro is used to determine if an Ansi character is Hpfs legal.
//

#define FsRtlIsAnsiCharacterLegalHpfs(C,WILD_OK) (                 \
    FsRtlTestAnsiCharacter((C), TRUE, (WILD_OK), FSRTL_HPFS_LEGAL) \
)

//
//  The following macro is used to determine if an Ansi character is Ntfs legal.
//

#define FsRtlIsAnsiCharacterLegalNtfs(C,WILD_OK) (                 \
    FsRtlTestAnsiCharacter((C), TRUE, (WILD_OK), FSRTL_NTFS_LEGAL) \
)

//
//  The following macro is used to determine if an Ansi character is
//  legal in an Ntfs stream name
//

#define FsRtlIsAnsiCharacterLegalNtfsStream(C,WILD_OK) (                    \
    FsRtlTestAnsiCharacter((C), TRUE, (WILD_OK), FSRTL_NTFS_STREAM_LEGAL)   \
)

//
//  The following macro is used to determine if an Ansi character is legal,
//  according to the caller's specification.
//

#define FsRtlIsAnsiCharacterLegal(C,FLAGS) (          \
    FsRtlTestAnsiCharacter((C), TRUE, FALSE, (FLAGS)) \
)

//
//  The following macro is used to test attributes of an Ansi character,
//  according to the caller's specified flags.
//

#define FsRtlTestAnsiCharacter(C, DEFAULT_RET, WILD_OK, FLAGS) (            \
        ((SCHAR)(C) < 0) ? DEFAULT_RET :                                    \
                           FlagOn( LEGAL_ANSI_CHARACTER_ARRAY[(C)],         \
                                   (FLAGS) |                                \
                                   ((WILD_OK) ? FSRTL_WILD_CHARACTER : 0) ) \
)


//
//  The following two macros use global data defined in ntos\rtl\nlsdata.c
//
//  BOOLEAN
//  FsRtlIsLeadDbcsCharacter (
//      IN UCHAR DbcsCharacter
//      );
//
//  /*++
//
//  Routine Description:
//
//      This routine takes the first bytes of a Dbcs character and
//      returns whether it is a lead byte in the system code page.
//
//  Arguments:
//
//      DbcsCharacter - Supplies the input character being examined
//
//  Return Value:
//
//      BOOLEAN - TRUE if the input character is a dbcs lead and
//              FALSE otherwise
//
//  --*/
//
//

#define FsRtlIsLeadDbcsCharacter(DBCS_CHAR) (                      \
    (BOOLEAN)((UCHAR)(DBCS_CHAR) < 0x80 ? FALSE :                  \
              (NLS_MB_CODE_PAGE_TAG &&                             \
               (NLS_OEM_LEAD_BYTE_INFO[(UCHAR)(DBCS_CHAR)] != 0))) \
)

NTKERNELAPI
VOID
FsRtlDissectDbcs (
    IN ANSI_STRING InputName,
    OUT PANSI_STRING FirstPart,
    OUT PANSI_STRING RemainingPart
    );

NTKERNELAPI
BOOLEAN
FsRtlDoesDbcsContainWildCards (
    IN PANSI_STRING Name
    );

NTKERNELAPI
BOOLEAN
FsRtlIsDbcsInExpression (
    IN PANSI_STRING Expression,
    IN PANSI_STRING Name
    );

NTKERNELAPI
BOOLEAN
FsRtlIsFatDbcsLegal (
    IN ANSI_STRING DbcsName,
    IN BOOLEAN WildCardsPermissible,
    IN BOOLEAN PathNamePermissible,
    IN BOOLEAN LeadingBackslashPermissible
    );

// end_ntosp

NTKERNELAPI
BOOLEAN
FsRtlIsHpfsDbcsLegal (
    IN ANSI_STRING DbcsName,
    IN BOOLEAN WildCardsPermissible,
    IN BOOLEAN PathNamePermissible,
    IN BOOLEAN LeadingBackslashPermissible
    );


//
//  Exception filter routines, implemented in Filter.c
//

NTKERNELAPI
NTSTATUS
FsRtlNormalizeNtstatus (
    IN NTSTATUS Exception,
    IN NTSTATUS GenericException
    );

NTKERNELAPI
BOOLEAN
FsRtlIsNtstatusExpected (
    IN NTSTATUS Exception
    );

//
//  The following procedures are used to allocate executive pool and raise
//  insufficient resource status if pool isn't currently available.
//

#define FsRtlAllocatePoolWithTag(PoolType, NumberOfBytes, Tag)                \
    ExAllocatePoolWithTag((POOL_TYPE)((PoolType) | POOL_RAISE_IF_ALLOCATION_FAILURE), \
                          NumberOfBytes,                                      \
                          Tag)


#define FsRtlAllocatePoolWithQuotaTag(PoolType, NumberOfBytes, Tag)           \
    ExAllocatePoolWithQuotaTag((POOL_TYPE)((PoolType) | POOL_RAISE_IF_ALLOCATION_FAILURE), \
                               NumberOfBytes,                                 \
                               Tag)

//
//  The following function allocates a resource from the FsRtl pool.
//

NTKERNELAPI
PERESOURCE
FsRtlAllocateResource (
    );


//
//  Large Integer Mapped Control Blocks routines, implemented in LargeMcb.c
//
//  Originally this structure was truly opaque and code outside largemcb was
//  never allowed to examine or alter the structures.  However, for performance
//  reasons we want to allow ntfs the ability to quickly truncate down the
//  mcb without the overhead of an actual call to largemcb.c.  So to do that we
//  need to export the structure.  This structure is not exact.  The Mapping field
//  is declared here as a pvoid but largemcb.c it is a pointer to mapping pairs.
//

typedef struct _BASE_MCB {
    ULONG MaximumPairCount;
    ULONG PairCount;
    POOL_TYPE PoolType;
    PVOID Mapping;
} BASE_MCB;
typedef BASE_MCB *PBASE_MCB;

typedef struct _LARGE_MCB {
    PFAST_MUTEX FastMutex;
    BASE_MCB BaseMcb;
} LARGE_MCB;
typedef LARGE_MCB *PLARGE_MCB;


NTKERNELAPI
VOID
FsRtlInitializeLargeMcb (
    IN PLARGE_MCB Mcb,
    IN POOL_TYPE PoolType
    );

NTKERNELAPI
VOID
FsRtlUninitializeLargeMcb (
    IN PLARGE_MCB Mcb
    );

NTKERNELAPI
VOID
FsRtlResetLargeMcb (
    IN PLARGE_MCB Mcb,
    IN BOOLEAN SelfSynchronized
    );

NTKERNELAPI
VOID
FsRtlTruncateLargeMcb (
    IN PLARGE_MCB Mcb,
    IN LONGLONG Vbn
    );

NTKERNELAPI
BOOLEAN
FsRtlAddLargeMcbEntry (
    IN PLARGE_MCB Mcb,
    IN LONGLONG Vbn,
    IN LONGLONG Lbn,
    IN LONGLONG SectorCount
    );

NTKERNELAPI
VOID
FsRtlRemoveLargeMcbEntry (
    IN PLARGE_MCB Mcb,
    IN LONGLONG Vbn,
    IN LONGLONG SectorCount
    );

NTKERNELAPI
BOOLEAN
FsRtlLookupLargeMcbEntry (
    IN PLARGE_MCB Mcb,
    IN LONGLONG Vbn,
    OUT PLONGLONG Lbn OPTIONAL,
    OUT PLONGLONG SectorCountFromLbn OPTIONAL,
    OUT PLONGLONG StartingLbn OPTIONAL,
    OUT PLONGLONG SectorCountFromStartingLbn OPTIONAL,
    OUT PULONG Index OPTIONAL
    );

NTKERNELAPI
BOOLEAN
FsRtlLookupLastLargeMcbEntry (
    IN PLARGE_MCB Mcb,
    OUT PLONGLONG Vbn,
    OUT PLONGLONG Lbn
    );

NTKERNELAPI
BOOLEAN
FsRtlLookupLastLargeMcbEntryAndIndex (
    IN PLARGE_MCB OpaqueMcb,
    OUT PLONGLONG LargeVbn,
    OUT PLONGLONG LargeLbn,
    OUT PULONG Index
    );

NTKERNELAPI
ULONG
FsRtlNumberOfRunsInLargeMcb (
    IN PLARGE_MCB Mcb
    );

NTKERNELAPI
BOOLEAN
FsRtlGetNextLargeMcbEntry (
    IN PLARGE_MCB Mcb,
    IN ULONG RunIndex,
    OUT PLONGLONG Vbn,
    OUT PLONGLONG Lbn,
    OUT PLONGLONG SectorCount
    );

NTKERNELAPI
BOOLEAN
FsRtlSplitLargeMcb (
    IN PLARGE_MCB Mcb,
    IN LONGLONG Vbn,
    IN LONGLONG Amount
    );

//
//  Unsynchronzied base mcb functions. There is one of these for every
//  large mcb equivalent function - they are identical other than lack of
//  synchronization 
//  

NTKERNELAPI
VOID
FsRtlInitializeBaseMcb (
    IN PBASE_MCB Mcb,
    IN POOL_TYPE PoolType
    );

NTKERNELAPI
VOID
FsRtlUninitializeBaseMcb (
    IN PBASE_MCB Mcb
    );

NTKERNELAPI
VOID
FsRtlResetBaseMcb (
    IN PBASE_MCB Mcb
    );

NTKERNELAPI
VOID
FsRtlTruncateBaseMcb (
    IN PBASE_MCB Mcb,
    IN LONGLONG Vbn
    );

NTKERNELAPI
BOOLEAN
FsRtlAddBaseMcbEntry (
    IN PBASE_MCB Mcb,
    IN LONGLONG Vbn,
    IN LONGLONG Lbn,
    IN LONGLONG SectorCount
    );

NTKERNELAPI
VOID
FsRtlRemoveBaseMcbEntry (
    IN PBASE_MCB Mcb,
    IN LONGLONG Vbn,
    IN LONGLONG SectorCount
    );

NTKERNELAPI
BOOLEAN
FsRtlLookupBaseMcbEntry (
    IN PBASE_MCB Mcb,
    IN LONGLONG Vbn,
    OUT PLONGLONG Lbn OPTIONAL,
    OUT PLONGLONG SectorCountFromLbn OPTIONAL,
    OUT PLONGLONG StartingLbn OPTIONAL,
    OUT PLONGLONG SectorCountFromStartingLbn OPTIONAL,
    OUT PULONG Index OPTIONAL
    );

NTKERNELAPI
BOOLEAN
FsRtlLookupLastBaseMcbEntry (
    IN PBASE_MCB Mcb,
    OUT PLONGLONG Vbn,
    OUT PLONGLONG Lbn
    );

NTKERNELAPI
BOOLEAN
FsRtlLookupLastBaseMcbEntryAndIndex (
    IN PBASE_MCB OpaqueMcb,
    OUT PLONGLONG LargeVbn,
    OUT PLONGLONG LargeLbn,
    OUT PULONG Index
    );

NTKERNELAPI
ULONG
FsRtlNumberOfRunsInBaseMcb (
    IN PBASE_MCB Mcb
    );

NTKERNELAPI
BOOLEAN
FsRtlGetNextBaseMcbEntry (
    IN PBASE_MCB Mcb,
    IN ULONG RunIndex,
    OUT PLONGLONG Vbn,
    OUT PLONGLONG Lbn,
    OUT PLONGLONG SectorCount
    );

NTKERNELAPI
BOOLEAN
FsRtlSplitBaseMcb (
    IN PBASE_MCB Mcb,
    IN LONGLONG Vbn,
    IN LONGLONG Amount
    );


//
//  Mapped Control Blocks routines, implemented in Mcb.c
//
//  An MCB is an opaque structure but we need to declare the size of
//  it here so that users can allocate space for one.  Consequently the
//  size computation here must be updated by hand if the MCB changes.
//

typedef struct _MCB {
    LARGE_MCB DummyFieldThatSizesThisStructureCorrectly;
} MCB;
typedef MCB *PMCB;

NTKERNELAPI
VOID
FsRtlInitializeMcb (
    IN PMCB Mcb,
    IN POOL_TYPE PoolType
    );

NTKERNELAPI
VOID
FsRtlUninitializeMcb (
    IN PMCB Mcb
    );

NTKERNELAPI
VOID
FsRtlTruncateMcb (
    IN PMCB Mcb,
    IN VBN Vbn
    );

NTKERNELAPI
BOOLEAN
FsRtlAddMcbEntry (
    IN PMCB Mcb,
    IN VBN Vbn,
    IN LBN Lbn,
    IN ULONG SectorCount
    );

NTKERNELAPI
VOID
FsRtlRemoveMcbEntry (
    IN PMCB Mcb,
    IN VBN Vbn,
    IN ULONG SectorCount
    );

NTKERNELAPI
BOOLEAN
FsRtlLookupMcbEntry (
    IN PMCB Mcb,
    IN VBN Vbn,
    OUT PLBN Lbn,
    OUT PULONG SectorCount OPTIONAL,
    OUT PULONG Index
    );

NTKERNELAPI
BOOLEAN
FsRtlLookupLastMcbEntry (
    IN PMCB Mcb,
    OUT PVBN Vbn,
    OUT PLBN Lbn
    );

NTKERNELAPI
ULONG
FsRtlNumberOfRunsInMcb (
    IN PMCB Mcb
    );

NTKERNELAPI
BOOLEAN
FsRtlGetNextMcbEntry (
    IN PMCB Mcb,
    IN ULONG RunIndex,
    OUT PVBN Vbn,
    OUT PLBN Lbn,
    OUT PULONG SectorCount
    );

//
//  Fault Tolerance routines, implemented in FaultTol.c
//
//  The routines in this package implement routines that help file
//  systems interact with the FT device drivers.
//

NTKERNELAPI
NTSTATUS
FsRtlBalanceReads (
    IN PDEVICE_OBJECT TargetDevice
    );

// end_ntifs
NTKERNELAPI
NTSTATUS
FsRtlSyncVolumes (
    IN PDEVICE_OBJECT TargetDevice,
    IN PLARGE_INTEGER ByteOffset OPTIONAL,
    IN PLARGE_INTEGER ByteCount
    );

// begin_ntifs

//
//  Oplock routines, implemented in Oplock.c
//
//  An OPLOCK is an opaque structure, we declare it as a PVOID and
//  allocate the actual memory only when needed.
//

typedef PVOID OPLOCK, *POPLOCK;

typedef
VOID
(*POPLOCK_WAIT_COMPLETE_ROUTINE) (
    IN PVOID Context,
    IN PIRP Irp
    );

typedef
VOID
(*POPLOCK_FS_PREPOST_IRP) (
    IN PVOID Context,
    IN PIRP Irp
    );

NTKERNELAPI
VOID
FsRtlInitializeOplock (
    IN OUT POPLOCK Oplock
    );

NTKERNELAPI
VOID
FsRtlUninitializeOplock (
    IN OUT POPLOCK Oplock
    );

NTKERNELAPI
NTSTATUS
FsRtlOplockFsctrl (
    IN POPLOCK Oplock,
    IN PIRP Irp,
    IN ULONG OpenCount
    );

NTKERNELAPI
NTSTATUS
FsRtlCheckOplock (
    IN POPLOCK Oplock,
    IN PIRP Irp,
    IN PVOID Context,
    IN POPLOCK_WAIT_COMPLETE_ROUTINE CompletionRoutine OPTIONAL,
    IN POPLOCK_FS_PREPOST_IRP PostIrpRoutine OPTIONAL
    );

NTKERNELAPI
BOOLEAN
FsRtlOplockIsFastIoPossible (
    IN POPLOCK Oplock
    );

NTKERNELAPI
BOOLEAN
FsRtlCurrentBatchOplock (
    IN POPLOCK Oplock
    );


//
//  Volume lock/unlock notification routines, implemented in PnP.c
//
//  These routines provide PnP volume lock notification support
//  for all filesystems.
//

#define FSRTL_VOLUME_DISMOUNT           1
#define FSRTL_VOLUME_DISMOUNT_FAILED    2
#define FSRTL_VOLUME_LOCK               3
#define FSRTL_VOLUME_LOCK_FAILED        4
#define FSRTL_VOLUME_UNLOCK             5
#define FSRTL_VOLUME_MOUNT              6

NTKERNELAPI
NTSTATUS
FsRtlNotifyVolumeEvent (
    IN PFILE_OBJECT FileObject,
    IN ULONG EventCode
    );

//
//  Notify Change routines, implemented in Notify.c
//
//  These routines provide Notify Change support for all filesystems.
//  Any of the 'Full' notify routines will support returning the
//  change information into the user's buffer.
//

typedef PVOID PNOTIFY_SYNC;

typedef
BOOLEAN (*PCHECK_FOR_TRAVERSE_ACCESS) (
            IN PVOID NotifyContext,
            IN PVOID TargetContext,
            IN PSECURITY_SUBJECT_CONTEXT SubjectContext
            );

typedef
BOOLEAN (*PFILTER_REPORT_CHANGE) (
            IN PVOID NotifyContext,
            IN PVOID FilterContext
            );

NTKERNELAPI
VOID
FsRtlNotifyInitializeSync (
    IN PNOTIFY_SYNC *NotifySync
    );

NTKERNELAPI
VOID
FsRtlNotifyUninitializeSync (
    IN PNOTIFY_SYNC *NotifySync
    );

// end_ntifs
NTKERNELAPI
VOID
FsRtlNotifyChangeDirectory (
    IN PNOTIFY_SYNC NotifySync,
    IN PVOID FsContext,
    IN PSTRING FullDirectoryName,
    IN PLIST_ENTRY NotifyList,
    IN BOOLEAN WatchTree,
    IN ULONG CompletionFilter,
    IN PIRP NotifyIrp
    );

// begin_ntifs
NTKERNELAPI
VOID
FsRtlNotifyFullChangeDirectory (
    IN PNOTIFY_SYNC NotifySync,
    IN PLIST_ENTRY NotifyList,
    IN PVOID FsContext,
    IN PSTRING FullDirectoryName,
    IN BOOLEAN WatchTree,
    IN BOOLEAN IgnoreBuffer,
    IN ULONG CompletionFilter,
    IN PIRP NotifyIrp,
    IN PCHECK_FOR_TRAVERSE_ACCESS TraverseCallback OPTIONAL,
    IN PSECURITY_SUBJECT_CONTEXT SubjectContext OPTIONAL
    );

NTKERNELAPI
VOID
FsRtlNotifyFilterChangeDirectory (
    IN PNOTIFY_SYNC NotifySync,
    IN PLIST_ENTRY NotifyList,
    IN PVOID FsContext,
    IN PSTRING FullDirectoryName,
    IN BOOLEAN WatchTree,
    IN BOOLEAN IgnoreBuffer,
    IN ULONG CompletionFilter,
    IN PIRP NotifyIrp,
    IN PCHECK_FOR_TRAVERSE_ACCESS TraverseCallback OPTIONAL,
    IN PSECURITY_SUBJECT_CONTEXT SubjectContext OPTIONAL,
    IN PFILTER_REPORT_CHANGE FilterCallback OPTIONAL
    );

NTKERNELAPI
VOID
FsRtlNotifyFilterReportChange (
    IN PNOTIFY_SYNC NotifySync,
    IN PLIST_ENTRY NotifyList,
    IN PSTRING FullTargetName,
    IN USHORT TargetNameOffset,
    IN PSTRING StreamName OPTIONAL,
    IN PSTRING NormalizedParentName OPTIONAL,
    IN ULONG FilterMatch,
    IN ULONG Action,
    IN PVOID TargetContext,
    IN PVOID FilterContext
    );

// end_ntifs
NTKERNELAPI
VOID
FsRtlNotifyReportChange (
    IN PNOTIFY_SYNC NotifySync,
    IN PLIST_ENTRY NotifyList,
    IN PSTRING FullTargetName,
    IN PSTRING TargetName,
    IN ULONG FilterMatch
    );

// begin_ntifs
NTKERNELAPI
VOID
FsRtlNotifyFullReportChange (
    IN PNOTIFY_SYNC NotifySync,
    IN PLIST_ENTRY NotifyList,
    IN PSTRING FullTargetName,
    IN USHORT TargetNameOffset,
    IN PSTRING StreamName OPTIONAL,
    IN PSTRING NormalizedParentName OPTIONAL,
    IN ULONG FilterMatch,
    IN ULONG Action,
    IN PVOID TargetContext
    );

NTKERNELAPI
VOID
FsRtlNotifyCleanup (
    IN PNOTIFY_SYNC NotifySync,
    IN PLIST_ENTRY NotifyList,
    IN PVOID FsContext
    );


//
//  Unicode Name support routines, implemented in Name.c
//
//  The routines here are used to manipulate unicode names
//

//
//  The following macro is used to determine if a character is wild.
//

#define FsRtlIsUnicodeCharacterWild(C) (                                \
      (((C) >= 0x40) ? FALSE : FlagOn( LEGAL_ANSI_CHARACTER_ARRAY[(C)], \
                                       FSRTL_WILD_CHARACTER ) )         \
)

NTKERNELAPI
VOID
FsRtlDissectName (
    IN UNICODE_STRING Path,
    OUT PUNICODE_STRING FirstName,
    OUT PUNICODE_STRING RemainingName
    );

NTKERNELAPI
BOOLEAN
FsRtlDoesNameContainWildCards (
    IN PUNICODE_STRING Name
    );

NTKERNELAPI
BOOLEAN
FsRtlAreNamesEqual (
    PCUNICODE_STRING ConstantNameA,
    PCUNICODE_STRING ConstantNameB,
    IN BOOLEAN IgnoreCase,
    IN PCWCH UpcaseTable OPTIONAL
    );

NTKERNELAPI
BOOLEAN
FsRtlIsNameInExpression (
    IN PUNICODE_STRING Expression,
    IN PUNICODE_STRING Name,
    IN BOOLEAN IgnoreCase,
    IN PWCH UpcaseTable OPTIONAL
    );


//
//  Stack Overflow support routine, implemented in StackOvf.c
//

typedef
VOID
(*PFSRTL_STACK_OVERFLOW_ROUTINE) (
    IN PVOID Context,
    IN PKEVENT Event
    );

NTKERNELAPI
VOID
FsRtlPostStackOverflow (
    IN PVOID Context,
    IN PKEVENT Event,
    IN PFSRTL_STACK_OVERFLOW_ROUTINE StackOverflowRoutine
    );

NTKERNELAPI
VOID
FsRtlPostPagingFileStackOverflow (
    IN PVOID Context,
    IN PKEVENT Event,
    IN PFSRTL_STACK_OVERFLOW_ROUTINE StackOverflowRoutine
    );

//
// UNC Provider support
//

NTKERNELAPI
NTSTATUS
FsRtlRegisterUncProvider(
    IN OUT PHANDLE MupHandle,
    IN PUNICODE_STRING RedirectorDeviceName,
    IN BOOLEAN MailslotsSupported
    );

NTKERNELAPI
VOID
FsRtlDeregisterUncProvider(
    IN HANDLE Handle
    );
// end_ntifs

// begin_ntifs

//
//  File System Filter PerStream Context Support
//

//
//  Filesystem filter drivers use these APIs to associate context
//  with open streams (for filesystems that support this).
//

//
//  OwnerId should uniquely identify a particular filter driver
//  (e.g. the address of the driver's device object).
//  InstanceId can be used to distinguish distinct contexts associated
//  by a filter driver with a single stream (e.g. the address of the
//  PerStream Context structure).
//

//
//  This structure needs to be embedded within the users context that
//  they want to associate with a given stream
//

typedef struct _FSRTL_PER_STREAM_CONTEXT {
    //
    //  This is linked into the StreamContext list inside the 
    //  FSRTL_ADVANCED_FCB_HEADER structure.
    //

    LIST_ENTRY Links;

    //
    //  A Unique ID for this filter (ex: address of Driver Object, Device
    //  Object, or Device Extension)
    //

    PVOID OwnerId;

    //
    //  An optional ID to differentiate different contexts for the same
    //  filter.
    //

    PVOID InstanceId;

    //
    //  A callback routine which is called by the underlying file system
    //  when the stream is being torn down.  When this routine is called
    //  the given context has already been removed from the context linked
    //  list.  The callback routine cannot recursively call down into the
    //  filesystem or acquire any of their resources which they might hold
    //  when calling the filesystem outside of the callback.  This must
    //  be defined.
    //

    PFREE_FUNCTION FreeCallback;

} FSRTL_PER_STREAM_CONTEXT, *PFSRTL_PER_STREAM_CONTEXT;


//
//  This will initialize the given FSRTL_PER_STREAM_CONTEXT structure.  This
//  should be used before calling "FsRtlInsertPerStreamContext".
//

#define FsRtlInitPerStreamContext( _fc, _owner, _inst, _cb)   \
    ((_fc)->OwnerId = (_owner),                               \
     (_fc)->InstanceId = (_inst),                             \
     (_fc)->FreeCallback = (_cb))

//
//  Given a FileObject this will return the StreamContext pointer that
//  needs to be passed into the other FsRtl PerStream Context routines.
//

#define FsRtlGetPerStreamContextPointer(_fo) \
    ((PFSRTL_ADVANCED_FCB_HEADER)((_fo)->FsContext))

//
//  This will test to see if PerStream contexts are supported for the given
//  FileObject
//

#define FsRtlSupportsPerStreamContexts(_fo)                     \
    ((NULL != FsRtlGetPerStreamContextPointer(_fo)) &&          \
     FlagOn(FsRtlGetPerStreamContextPointer(_fo)->Flags2,       \
                    FSRTL_FLAG2_SUPPORTS_FILTER_CONTEXTS))

//
//  Associate the context at Ptr with the given stream.  The Ptr structure
//  should be filled in by the caller before calling this routine (see
//  FsRtlInitPerStreamContext).  If the underlying filesystem does not support
//  filter contexts, STATUS_INVALID_DEVICE_REQUEST will be returned.
//

NTKERNELAPI
NTSTATUS
FsRtlInsertPerStreamContext (
    IN PFSRTL_ADVANCED_FCB_HEADER PerStreamContext,
    IN PFSRTL_PER_STREAM_CONTEXT Ptr
    );

//
//  Lookup a filter context associated with the stream specified.  The first
//  context matching OwnerId (and InstanceId, if present) is returned.  By not
//  specifying InstanceId, a filter driver can search for any context that it
//  has previously associated with a stream.  If no matching context is found,
//  NULL is returned.  If the file system does not support filter contexts,
//  NULL is returned.
//

NTKERNELAPI
PFSRTL_PER_STREAM_CONTEXT
FsRtlLookupPerStreamContextInternal (
    IN PFSRTL_ADVANCED_FCB_HEADER StreamContext,
    IN PVOID OwnerId OPTIONAL,
    IN PVOID InstanceId OPTIONAL
    );

#define FsRtlLookupPerStreamContext(_sc, _oid, _iid)                          \
 (((NULL != (_sc)) &&                                                         \
   FlagOn((_sc)->Flags2,FSRTL_FLAG2_SUPPORTS_FILTER_CONTEXTS) &&              \
   !IsListEmpty(&(_sc)->FilterContexts)) ?                                    \
        FsRtlLookupPerStreamContextInternal((_sc), (_oid), (_iid)) :          \
        NULL)

//
//  Normally, contexts should be deleted when the file system notifies the
//  filter that the stream is being closed.  There are cases when a filter
//  may want to remove all existing contexts for a specific volume.  This
//  routine should be called at those times.  This routine should NOT be
//  called for the following cases:
//      - Inside your FreeCallback handler - The underlying file system has
//        already removed it from the linked list).
//      - Inside your IRP_CLOSE handler - If you do this then you will not
//        be notified when the stream is torn down.
//
//  This functions identically to FsRtlLookupPerStreamContext, except that the
//  returned context has been removed from the list.
//

NTKERNELAPI
PFSRTL_PER_STREAM_CONTEXT
FsRtlRemovePerStreamContext (
    IN PFSRTL_ADVANCED_FCB_HEADER StreamContext,
    IN PVOID OwnerId OPTIONAL,
    IN PVOID InstanceId OPTIONAL
    );


//
//  APIs for file systems to use for initializing and cleaning up
//  the Advaned FCB Header fields for PerStreamContext support
//

//
//  This will properly initialize the advanced header so that it can be
//  used with PerStream contexts.  
//  Note:  A fast mutex must be placed in an advanced header.  It is the
//         caller's responsibility to properly create and initialize this
//         mutex before calling this macro.  The mutex field is only set
//         if a non-NULL value is passed in.
//

#define FsRtlSetupAdvancedHeader( _advhdr, _fmutx )                         \
{                                                                           \
    SetFlag( (_advhdr)->Flags, FSRTL_FLAG_ADVANCED_HEADER );                \
    SetFlag( (_advhdr)->Flags2, FSRTL_FLAG2_SUPPORTS_FILTER_CONTEXTS );     \
    InitializeListHead( &(_advhdr)->FilterContexts );                       \
    if ((_fmutx) != NULL) {                                                 \
        (_advhdr)->FastMutex = (_fmutx);                                    \
    }                                                                       \
}

//
// File systems call this API to free any filter contexts still associated
// with an FSRTL_COMMON_FCB_HEADER that they are tearing down.
// The FreeCallback routine for each filter context will be called.
//

NTKERNELAPI
VOID
FsRtlTeardownPerStreamContexts (
  IN PFSRTL_ADVANCED_FCB_HEADER AdvancedHeader
  );

// end_ntifs


//
//  File System Filter PerFileObject Context Support
//

//
//  Filesystem filter drivers use these APIs to associate context
//  with individual open files.  For now these are only supported on file
//  objects with a FileObject extension which are only created by using
//  IoCreateFileSpecifyDeviceObjectHint.
//

//
//  OwnerId should uniquely identify a particular filter driver
//  (e.g. the address of the driver's device object).
//  InstanceId can be used to distinguish distinct contexts associated
//  by a filter driver with a single stream (e.g. the address of the
//  fileobject).
//

//
//  This structure needs to be embedded within the users context that
//  they want to associate with a given stream
//

typedef struct _FSRTL_PER_FILEOBJECT_CONTEXT {
    //
    //  This is linked into the File Object
    //

    LIST_ENTRY Links;

    //
    //  A Unique ID for this filter (ex: address of Driver Object, Device
    //  Object, or Device Extension)
    //

    PVOID OwnerId;

    //
    //  An optional ID to differentiate different contexts for the same
    //  filter.
    //

    PVOID InstanceId;

} FSRTL_PER_FILEOBJECT_CONTEXT, *PFSRTL_PER_FILEOBJECT_CONTEXT;


//
//  This will initialize the given FSRTL_PER_FILEOBJECT_CONTEXT structure.  This
//  should be used before calling "FsRtlInsertPerFileObjectContext".
//

#define FsRtlInitPerFileObjectContext( _fc, _owner, _inst )         \
    ((_fc)->OwnerId = (_owner),                                     \
     (_fc)->InstanceId = (_inst))                                   \

//
//  This will test to see if PerFileObject contexts are supported for the given
//  FileObject
//

#define FsRtlSupportsPerFileObjectContexts(_fo) \
    FlagOn((_fo)->Flags,FO_FILE_OBJECT_HAS_EXTENSION)

//
//  Associate the context at Ptr with the given FileObject.  The Ptr
//  structure should be filled in by the caller before calling this
//  routine (see FsRtlInitPerFileObjectContext).  If this file object does not
//  support filter contexts, STATUS_INVALID_DEVICE_REQUEST will be returned.
//

NTKERNELAPI
NTSTATUS
FsRtlInsertPerFileObjectContext (
    IN PFILE_OBJECT FileObject,
    IN PFSRTL_PER_FILEOBJECT_CONTEXT Ptr
    );

//
//  Lookup a filter context associated with the FileObject specified.  The first
//  context matching OwnerId (and InstanceId, if present) is returned.  By not
//  specifying InstanceId, a filter driver can search for any context that it
//  has previously associated with a stream.  If no matching context is found,
//  NULL is returned.  If the FileObject does not support contexts, 
//  NULL is returned.
//

NTKERNELAPI
PFSRTL_PER_FILEOBJECT_CONTEXT
FsRtlLookupPerFileObjectContext (
    IN PFILE_OBJECT FileObject,
    IN PVOID OwnerId OPTIONAL,
    IN PVOID InstanceId OPTIONAL
    );

//
//  Normally, contexts should be deleted when the IoManager notifies the
//  filter that the FileObject is being freed.  There are cases when a filter
//  may want to remove all existing contexts for a specific volume.  This
//  routine should be called at those times.  This routine should NOT be
//  called for the following case:
//      - Inside your FreeCallback handler - The IoManager has already removed
//        it from the linked list.
//
//  This functions identically to FsRtlLookupPerFileObjectContext, except that
//  the returned context has been removed from the list.
//

NTKERNELAPI
PFSRTL_PER_FILEOBJECT_CONTEXT
FsRtlRemovePerFileObjectContext (
    IN PFILE_OBJECT FileObject,
    IN PVOID OwnerId OPTIONAL,
    IN PVOID InstanceId OPTIONAL
    );

//
//  Internal routine to free the context control structure
//

VOID
FsRtlPTeardownPerFileObjectContexts (
  IN PFILE_OBJECT FileObject
  );


// begin_ntifs
//++
//
//  VOID
//  FsRtlCompleteRequest (
//      IN PIRP Irp,
//      IN NTSTATUS Status
//      );
//
//  Routine Description:
//
//      This routine is used to complete an IRP with the indicated
//      status.  It does the necessary raise and lower of IRQL.
//
//  Arguments:
//
//      Irp - Supplies a pointer to the Irp to complete
//
//      Status - Supplies the completion status for the Irp
//
//  Return Value:
//
//      None.
//
//--

#define FsRtlCompleteRequest(IRP,STATUS) {         \
    (IRP)->IoStatus.Status = (STATUS);             \
    IoCompleteRequest( (IRP), IO_DISK_INCREMENT ); \
}


//++
//
//  VOID
//  FsRtlEnterFileSystem (
//      );
//
//  Routine Description:
//
//      This routine is used when entering a file system (e.g., through its
//      Fsd entry point).  It ensures that the file system cannot be suspended
//      while running and thus block other file I/O requests.  Upon exit
//      the file system must call FsRtlExitFileSystem.
//
//  Arguments:
//
//  Return Value:
//
//      None.
//
//--

#define FsRtlEnterFileSystem() { \
    KeEnterCriticalRegion();     \
}

//++
//
//  VOID
//  FsRtlExitFileSystem (
//      );
//
//  Routine Description:
//
//      This routine is used when exiting a file system (e.g., through its
//      Fsd entry point).
//
//  Arguments:
//
//  Return Value:
//
//      None.
//
//--

#define FsRtlExitFileSystem() { \
    KeLeaveCriticalRegion();    \
}


VOID
FsRtlIncrementCcFastReadNotPossible( VOID );

VOID
FsRtlIncrementCcFastReadWait( VOID );

VOID
FsRtlIncrementCcFastReadNoWait( VOID );

VOID
FsRtlIncrementCcFastReadResourceMiss( VOID );

//
//  Returns TRUE if the given fileObject represents a paging file, returns
//  FALSE otherwise.
//

LOGICAL
FsRtlIsPagingFile (
    IN PFILE_OBJECT FileObject
    );

// end_ntifs

//
//  Callback for mm to inform the filesystems that a file has been mapped
// 

NTSTATUS 
FsRtlMappedFile( 
    IN PFILE_OBJECT FileObject,
    IN ULONG DesiredAccess,
    IN PLARGE_INTEGER FileOffset,
    IN PLARGE_INTEGER Length
    );

#endif // _FSRTL_