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Checking the Oplock State of IRP_MJ_FILE_SYSTEM_CONTROL

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The following IRP_MJ_FILE_SYSTEM_CONTROL operations check oplock state:

  • FSCTL_SET_ZERO_DATA

This information applies when a caller wants to zero the current contents of the given stream.

Conditions for a Level 2 request type:

  • Always break to None.

  • No acknowledgment is required; the operation proceeds immediately.

Conditions for all other request types:

  • Break on IRP_MJ_FILE_SYSTEM_CONTROL (for FSCTL_SET_ZERO_DATA) when the operation occurs on a FILE_OBJECT with an oplock key that differs from the key of the FILE_OBJECT that owns the oplock. If the oplock is broken, break to None.

  • Acknowledgment requirements vary as follows:

    • Read request: No acknowledgment is required; the operation proceeds immediately.

    • Read-Handle request: Although acknowledgment of the break is required, the operation continues immediately (for example, without waiting for the acknowledgment).

    • Level 1, Batch, Filter, Read-Write, and Read-Write-Handle requests: An acknowledgment must be received before the operation continues.