DEVICE_DATA_SET_LB_PROVISIONING_STATE structure

The DEVICE_DATA_SET_LB_PROVISIONING_STATE structure is returned by an IOCTL_STORAGE_MANAGE_DATA_SET_ATTRIBUTES request when requesting logical block provisioning information for a data set range.

Syntax


typedef struct _DEVICE_DATA_SET_LB_PROVISIONING_STATE {
  ULONG     Size;
  ULONG     Version;
  ULONGLONG SlabSizeInBytes;
  ULONG     SlabOffsetDeltaInBytes;
  ULONG     SlabAllocationBitMapBitCount;
  ULONG     SlabAllocationBitMapLength;
  ULONG     SlabAllocationBitMap[ANYSIZE_ARRAY];
} DEVICE_DATA_SET_LB_PROVISIONING_STATE, *PDEVICE_DATA_SET_LB_PROVISIONING_STATE;

Members

Size

The size of this structure, including the slab allocation bitmap, in bytes.

Version

The version of this structure.

SlabSizeInBytes

The size, in bytes, of a slab.

SlabOffsetDeltaInBytes

The difference, in bytes, from the offset specified in the data set range to the starting slab position.

SlabAllocationBitMapBitCount

The number of bits in the allocation bitmap mapping slabs for the data set range.

SlabAllocationBitMapLength

The number of ULONG array values containing the slab allocation bitmap.

SlabAllocationBitMap

A bitmap of slab allocations.

Remarks

Provisioning state information is returned when the Action member of DEVICE_MANAGE_DATA_SET_ATTRIBUTES is set to DeviceDsmAction_Allocation. The caller should include only one data set range in the system buffer at DataSetRangesOffset.

On return, the system buffer contains a DEVICE_MANAGE_DATA_SET_ATTRIBUTES_OUPUT structure followed by the DEVICE_DATA_SET_LB_PROVISIONING_STATE structure. The DEVICE_DATA_SET_LB_PROVISIONING_STATE structure begins at an offset from the beginning of the system buffer specified by OutputBlockOffset in DEVICE_MANAGE_DATA_SET_ATTRIBUTES_OUPUT.

Each bit in the allocation bitmap represents a slab mapping within the data set range requested. The bits correspond directly to the slabs in the data set range. This means that bit 0 in the bitmap marks the first slab in the range. A slab is mapped if the bit value = 1 and unmapped if the bit value = 0.

Space for SlabAllocationBitMap should be allocated based on the number of possible slabs in the requested data set range. The SlabAllocationBitMapLength of the bitmap returned is (number of slabs / 32) + ((number of slabs MOD 32) > 0 ? 1 : 0).

Slab size is determined by the OptimalUnmapGranularity member of DEVICE_LB_PROVISIONING_DESCRIPTOR returned from an IOCTL_STORAGE_QUERY_PROPERTY request. The length of the data set range provided should be a multiple of OptimalUnmapGranularity. When the range length is not a multiple of OptimalUnmapGranularity, it is reduced to be a multiple.

If the starting offset in the data set range is not aligned on a slab boundary, a multiple of OptimalUnmapGranularity, the offset will be adjusted to the next boundary. The difference between the requested offset and the adjusted offset is returned in SlabOffsetDeltaInBytes.

If the slab allocation total returned in SlabAllocationBitMapBitCount is not as expected because of data set range alignment or length adjustments, an additional request may be submitted with a data set range modified according to the values in both SlabAllocationBitMapBitCount and SlabOffsetDeltaInBytes. The new range will properly select the slabs left out of the bitmap returned by the previous request.

Requirements

Version

Available starting with Windows 8.

Header

Ntddstor.h (include Ntddstor.h)

See also

DEVICE_DATA_MANAGEMENT_SET_ACTION
DEVICE_MANAGE_DATA_SET_ATTRIBUTES
IOCTL_STORAGE_MANAGE_DATA_SET_ATTRIBUTES
IOCTL_STORAGE_QUERY_PROPERTY

 

 

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