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FsRtlCheckOplock routine

The FsRtlCheckOplock routine synchronizes the IRP for a file I/O operation with the file's current opportunistic lock (oplock) state.

Syntax


NTSTATUS FsRtlCheckOplock(
  _In_      POPLOCK Oplock,
  _In_      PIRP Irp,
  _In_opt_  PVOID Context,
  _In_opt_  POPLOCK_WAIT_COMPLETE_ROUTINE CompletionRoutine,
  _In_opt_  POPLOCK_FS_PREPOST_IRP PostIrpRoutine
);

Parameters

Oplock [in]

An opaque opportunistic lock pointer for the file. This pointer must have been initialized by a previous call to FsRtlInitializeOplock.

Irp [in]

A pointer to the IRP for the I/O operation.

Context [in, optional]

A pointer to caller-defined context information to be passed to the callback routines that the CompletionRoutine and PostIrpRoutine parameters point to.

CompletionRoutine [in, optional]

A pointer to a caller-supplied callback routine. If an opportunistic lock break is in progress, this routine is called when the break is completed. This parameter is optional and can be NULL. If it is NULL, the caller is put into a wait state until the opportunistic lock break is completed.

This routine is declared as follows:


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

This routine has the following parameters:

Context

A context information pointer that was passed in the Context parameter to FsRtlCheckOplock.

Irp

A pointer to the IRP for the I/O operation.

PostIrpRoutine [in, optional]

A pointer to a caller-supplied callback routine to be called if the I/O operation is posted to a work queue. This parameter is optional and can be NULL.

This routine is declared as follows:


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

Context

A context information pointer that was passed in the Context parameter to FsRtlCheckOplock.

Irp

A pointer to the IRP for the I/O operation.

Return value

The FsRtlCheckOplock routine returns STATUS_SUCCESS or an appropriate NTSTATUS code such as one of the following:

Return codeDescription
STATUS_CANCELLED

The IRP was canceled. STATUS_CANCELLED is an error code.

STATUS_CANNOT_BREAK_OPLOCK

If the IRP is an IRP_MJ_CREATE and FILE_OPEN_REQUIRING_OPLOCK is in the IRP's CreateOptions, the routine will not initiate a break of an existing opportunistic lock, but fails with STATUS_CANNOT_BREAK_OPLOCK.

STATUS_OPLOCK_BREAK_IN_PROGRESS

An opportunistic lock break is underway. The IRP is an IRP_MJ_CREATE request, and FILE_COMPLETE_IF_OPLOCKED was specified in the create options parameter for the operation. STATUS_OPLOCK_BREAK_IN_PROGRESS is a success code.

STATUS_PENDING

An opportunistic lock break has been initiated, and control of the IRP has been passed to the oplock package. If CompletionRoutine is NULL, this routine will block while the oplock break is processed, rather than return STATUS_PENDING. STATUS_PENDING is a success code.

 

Remarks

FsRtlCheckOplock synchronizes the IRP for an I/O operation with the current opportunistic lock state of a file according to the following conditions:

  • If the I/O operation will cause the opportunistic lock to break, the opportunistic lock break is initiated.

  • If the I/O operation cannot continue until the opportunistic lock break is complete, FsRtlCheckOplock returns STATUS_PENDING and calls the callback routine that the PostIrpRoutine parameter points to.

If a file system or filter driver uses opportunistic locks, it must call FsRtlCheckOplock from any dispatch routines for I/O operations that can cause opportunistic lock breaks. This rule applies to the following types of I/O operations, because these operations can cause opportunistic lock breaks:

IRP_MJ_CLEANUP

IRP_MJ_CREATE

IRP_MJ_FILE_SYSTEM_CONTROL

IRP_MJ_FLUSH_BUFFERS

IRP_MJ_LOCK_CONTROL

IRP_MJ_READ

IRP_MJ_SET_INFORMATION

IRP_MJ_WRITE

For detailed information about opportunistic locks, see the Microsoft Windows SDK documentation.

Minifilters should call FltCheckOplock instead of FsRtlCheckOplock.

Requirements

Version

This routine is available in Microsoft Windows 2000 and later versions of Windows operating systems.

Header

Ntifs.h (include FltKernel.h or Ntifs.h)

Library

Ntoskrnl.lib

IRQL

<= APC_LEVEL

See also

FltCheckOplock
FSCTL_OPBATCH_ACK_CLOSE_PENDING
FSCTL_OPLOCK_BREAK_ACK_NO_2
FSCTL_OPLOCK_BREAK_ACKNOWLEDGE
FSCTL_OPLOCK_BREAK_NOTIFY
FSCTL_REQUEST_BATCH_OPLOCK
FSCTL_REQUEST_FILTER_OPLOCK
FSCTL_REQUEST_OPLOCK_LEVEL_1
FSCTL_REQUEST_OPLOCK_LEVEL_2
FsRtlCurrentBatchOplock
FsRtlInitializeOplock
FsRtlOplockFsctrl
FsRtlOplockIsFastIoPossible
FsRtlUninitializeOplock

 

 

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