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REQUEST_OPLOCK_OUTPUT_BUFFER structure (winioctl.h)

  • Article

Contains the opportunistic lock (oplock) information returned by the FSCTL_REQUEST_OPLOCK control code.

Syntax

typedef struct _REQUEST_OPLOCK_OUTPUT_BUFFER {
  WORD        StructureVersion;
  WORD        StructureLength;
  DWORD       OriginalOplockLevel;
  DWORD       NewOplockLevel;
  DWORD       Flags;
  ACCESS_MASK AccessMode;
  WORD        ShareMode;
} REQUEST_OPLOCK_OUTPUT_BUFFER, *PREQUEST_OPLOCK_OUTPUT_BUFFER;

Members

StructureVersion

The version of the REQUEST_OPLOCK_OUTPUT_BUFFER structure that is being used.

StructureLength

The length of this structure, in bytes.

OriginalOplockLevel

One or more OPLOCK_LEVEL_CACHE_XXX values that indicate the level of the oplock that was broken.

For possible values, see the RequestedOplockLevel member of the REQUEST_OPLOCK_INPUT_BUFFER structure.

NewOplockLevel

One or more OPLOCK_LEVEL_CACHE_XXX values that indicate the level to which an oplock is being broken, or an oplock level that may be available for granting, depending on the operation returning this buffer.

For possible values, see the RequestedOplockLevel member of the REQUEST_OPLOCK_INPUT_BUFFER structure.

Flags

One or more REQUEST_OPLOCK_OUTPUT_FLAG_XXX values.

Value Meaning
REQUEST_OPLOCK_OUTPUT_FLAG_ACK_REQUIRED
 Indicates that an acknowledgment is required, and the oplock described in OriginalOplockLevel will continue to remain in force until the break is successfully acknowledged.
REQUEST_OPLOCK_OUTPUT_FLAG_MODES_PROVIDED
 Indicates that the ShareMode and AccessMode members contain the share and access flags, respectively, of the request causing the oplock break. For more information, see the Remarks section.

AccessMode

If the REQUEST_OPLOCK_OUTPUT_FLAG_MODES_PROVIDED flag is set and the OPLOCK_LEVEL_CACHE_HANDLE level is being lost in an oplock break, contains the access mode of the request that is causing the break.

ShareMode

If the REQUEST_OPLOCK_OUTPUT_FLAG_MODES_PROVIDED flag is set and the OPLOCK_LEVEL_CACHE_HANDLE level is being lost in an oplock break, contains the share mode of the request that is causing the break.

Remarks

The REQUEST_OPLOCK_OUTPUT_FLAG_MODES_PROVIDED flag indicates that the ShareMode and AccessMode fields contain the share and access flags, respectively, of the request causing the oplock break. This information may be provided on breaks where the OPLOCK_LEVEL_CACHE_HANDLE level is being lost and may be useful to callers who can close handles whose share and access modes conflict with the handle causing the break. This may enable them to maintain at least some handle cache state. Note that not all breaks where the OPLOCK_LEVEL_CACHE_HANDLE level is being lost will have this flag set. The primary case where this flag will be set is if the break is a result of a create operation that needs the OPLOCK_LEVEL_CACHE_HANDLE oplock to be broken to avoid failing with ERROR_SHARING_VIOLATION.

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

Oplock Semantics

REQUEST_OPLOCK_INPUT_BUFFER