MRxLowIOSubmit[LOWIO_OP_EXCLUSIVELOCK] routine

Article
03/14/2023

The MRxLowIOSubmit[LOWIO_OP_EXCLUSIVELOCK] routine is called by RDBSS to request that a network mini-redirector open an exclusive lock on a file object.

Syntax

PMRX_CALLDOWN MRxLowIOSubmit[LOWIO_OP_EXCLUSIVELOCK];

NTSTATUS MRxLowIOSubmit[LOWIO_OP_EXCLUSIVELOCK](
  _Inout_ PRX_CONTEXT RxContext
)
{ ... }

Parameters

RxContext [in, out]
A pointer to the RX_CONTEXT structure. This parameter contains the IRP that is requesting the operation.

Return value

MRxLowIOSubmit[LOWIO_OP_EXCLUSIVELOCK] returns STATUS_SUCCESS on success or an appropriate NTSTATUS value, such as one of the following:

Return code	Description
STATUS_CONNECTION_DISCONNECTED	The connection was disconnected.
STATUS_INSUFFICIENT_RESOURCES	There were insufficient resources to complete the request.
STATUS_INVALID_NETWORK_RESPONSE	An invalid response was received from the remote server.
STATUS_INVALID_PARAMETER	An invalid parameter was specified in RxContext.
STATUS_LINK_FAILED	The attempt to reconnect to a remote server to complete the request failed.
STATUS_NOT_IMPLEMENTED	This routine is not implemented.
STATUS_SHARING_VIOLATION	A sharing violation occurred.
STATUS_UNSUCCESSFUL	The call was unsuccessful.

Remarks

RDBSS calls MRxLowIOSubmit[LOWIO_OP_EXCLUSIVELOCK] in response to receiving an IRP_MJ_LOCK_CONTROL request with a minor code of IRP_MN_LOCK if IrpSp->Flags has the SL_EXCLUSIVE_LOCK bit set.

Before calling MRxLowIOSubmit[LOWIO_OP_EXCLUSIVELOCK], RDBSS modifies the following members in the RX_CONTEXT structure pointed to by the RxContext parameter:

The LowIoContext.Operation member is set to LOWIO_OP_EXCLUSIVELOCK.

The LowIoContext.ResourceThreadId member is set to the thread of the process that initiated the operation in RDBSS.

The LowIoContext.ParamsFor.Locks.ByteOffset member is set to the value of IrpSp->Parameters.LockControl.ByteOffset.QuadPart.

The LowIoContext.ParamsFor.Locks.Key member is set to the value of IrpSp->Parameters.LockControl.Key.

The LowIoContext.ParamsFor.Locks.Flags member is set to the value of IrpSp->Flags.

The LowIoContext.ParamsFor.Locks.Length member is set to the value of IrpSp->Parameters.LockControl.Length.QuadPart.

The LowIoContext.Operation member of the RX_CONTEXT structure specifies the low I/O operation to perform. It is possible for several of the low I/O routines to point to the same routine in a network mini-redirector because this LowIoContext.Operation member can be used to differentiate the low I/O operation that is requested. For example, all the I/O calls related to file locks could call the same low I/O routine in the network mini-redirector and that routine could use the LowIoContext.Operation member to differentiate between the lock and unlock operation that is requested.

If the MRxLowIOSubmit[LOWIO_OP_EXCLUSIVELOCK] routine can take a long time to complete, the network mini-redirector driver should release the FCB structure before initiating the network communication. The FCB structure can be released by calling RxReleaseFcbResourceForThreadInMRx. While the MRxLowIOSubmit[LOWIO_OP_EXCLUSIVELOCK] routine is processing, the LowIoContext.ResourceThreadId member of RX_CONTEXT is guaranteed to indicate the thread of the process that initiated the operation in RDBSS.

The LowIoContext.ResourceThreadId member of RX_CONTEXT can be used to release the FCB structure on behalf of another thread. When an asynchronous routine completes, the FCB structure that was acquired from the initial thread can be released.

Requirements

Target platform	Desktop
Header	Mrx.h (include Mrx.h)