REQUEST_OPLOCK_INPUT_BUFFER structure (winioctl.h)

Contains the information to request an opportunistic lock (oplock) or to acknowledge an oplock break with the FSCTL_REQUEST_OPLOCK control code.

Syntax

typedef struct _REQUEST_OPLOCK_INPUT_BUFFER {
  WORD  StructureVersion;
  WORD  StructureLength;
  DWORD RequestedOplockLevel;
  DWORD Flags;
} REQUEST_OPLOCK_INPUT_BUFFER, *PREQUEST_OPLOCK_INPUT_BUFFER;

Members

StructureVersion

The version of the REQUEST_OPLOCK_INPUT_BUFFER structure that is being used. Set this member to REQUEST_OPLOCK_CURRENT_VERSION.

StructureLength

The length of this structure, in bytes. Must be set to sizeof(REQUEST_OPLOCK_INPUT_BUFFER).

RequestedOplockLevel

A valid combination of the following oplock level values.

Value	Meaning
OPLOCK_LEVEL_CACHE_READ	Allows clients to cache reads. May be granted to multiple clients.
OPLOCK_LEVEL_CACHE_HANDLE	Allows clients to cache open handles. May be granted to multiple clients.
OPLOCK_LEVEL_CACHE_WRITE	Allows clients to cache writes and byte range locks. May be granted only to a single client.

 

Valid combinations of these values are as follows:

• OPLOCK_LEVEL_CACHE_READ
• OPLOCK_LEVEL_CACHE_READ | OPLOCK_LEVEL_CACHE_HANDLE
• OPLOCK_LEVEL_CACHE_READ | OPLOCK_LEVEL_CACHE_WRITE
• OPLOCK_LEVEL_CACHE_READ | OPLOCK_LEVEL_CACHE_WRITE | OPLOCK_LEVEL_CACHE_HANDLE

For more information about these value combinations, see FSCTL_REQUEST_OPLOCK.

Flags

A valid combination of the following request flag values.

Value	Meaning
REQUEST_OPLOCK_INPUT_FLAG_REQUEST	Request for a new oplock. Setting this flag together with REQUEST_OPLOCK_INPUT_FLAG_ACK is not valid and will cause the request to fail with ERROR_INVALID_PARAMETER.
REQUEST_OPLOCK_INPUT_FLAG_ACK	Acknowledgment of an oplock break. Setting this flag together with REQUEST_OPLOCK_ INPUT_FLAG_REQUEST is not valid and will cause the request to fail with ERROR_INVALID_PARAMETER.

Requirements

Requirement	Value
Minimum supported client	Windows 7 [desktop apps only]
Minimum supported server	Windows Server 2008 R2 [desktop apps only]
Header	winioctl.h (include Windows.h)

See also

FSCTL_REQUEST_OPLOCK

REQUEST_OPLOCK_OUTPUT_BUFFER