IOCTL_EHSTOR_DEVICE_SET_QUEUE_STATE IOCTL (ehstorioctl.h)
The IOCTL_EHSTOR_DEVICE_SET_QUEUE_STATE request is sent by silo drivers and applications to change the state of a storage device queue. IO requests in the storage device queue are held when the device is temporarily unauthorized.
Major code
Input buffer
The input buffer at Irp->AssociatedIrp.SystemBuffer contains an ACT_QUEUE_STATE structure. ACT_QUEUE_STATE is declared in ehstorioctl.h as the following.
typedef struct tagACT_QUEUE_STATE
{
BOOLEAN fFrozen;
} ACT_QUEUE_STATE;
Input buffer length
The length of an ACT_QUEUE_STATE structure.
Output buffer
None.
Output buffer length
None.
Status block
One of the following values can be returned in the Status field.
| Status Value | Description |
|---|---|
| STATUS_SUCCESS | The queue state was changed successfully. |
| STATUS_INVALID_BUFFER_SIZE | The input buffer length is too small. |
| STATUS_ACCESS_DENIED | The IOCTL request was not issued by a silo driver. |
Remarks
Silo drivers or applications can freeze the storage device IO request queue if temporary unauthorization is needed. Normally, temporary unauthorization occurs during low power states or when a policy requires locking of Enhanced Storage devices such as a locked user session. In such a case, it is preferable to put pending IO requests on hold rather than fail the IO requests and cause data loss.
To prevent abuse of the IOCTL_EHSTOR_DEVICE_SET_QUEUE_STATE request by applications, only a driver can issue this IOCTL. If sent from a user mode application, this request will fail with STATUS_ACCESS_DENIED.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Available starting with Windows 8 |
| Header | ehstorioctl.h (include EhStorIoctl.h) |