MOVE_FILE_DATA - NtDoc
Native API online documentation, based on the System Informer
(formerly Process Hacker) phnt
headers
// ntifs.h
typedef struct {
HANDLE FileHandle;
LARGE_INTEGER StartingVcn;
LARGE_INTEGER StartingLcn;
ULONG ClusterCount;
} MOVE_FILE_DATA, *PMOVE_FILE_DATA;
View the official Windows Driver Kit DDI reference// winioctl.h
typedef struct {
HANDLE FileHandle;
LARGE_INTEGER StartingVcn;
LARGE_INTEGER StartingLcn;
DWORD ClusterCount;
} MOVE_FILE_DATA, *PMOVE_FILE_DATA;
View the official Win32 API referenceNo description available.
The MOVE_FILE_DATA structure contains input data for the FSCTL_MOVE_FILE control code.
FileHandleHandle to the file to be moved.
StartingVcnA VCN (cluster number relative to the beginning of a file) of the first cluster to be moved.
StartingLcnAn LCN (cluster number on a volume) to which the VCN is to be moved.
ClusterCountThe count of clusters to be moved.
Contains input data for the FSCTL_MOVE_FILE control code.
FileHandleA handle to the file to be moved.
To retrieve a handle to a file, use CreateFile.
If the file is encrypted, the handle must have the FILE_READ_DATA, FILE_WRITE_DATA, FILE_APPEND_DATA, or FILE_EXECUTE access right. For more information, see File Security and Access Rights.
StartingVcnA VCN (cluster number relative to the beginning of a file) of the first cluster to be moved.
StartingLcnAn LCN (cluster number on a volume) to which the VCN is to be moved.
ClusterCountThe count of clusters to be moved.
To retrieve data to fill in this structure, use the DeviceIoControl function with the FSCTL_GET_RETRIEVAL_POINTERS control code.
The first cluster of a directory on a FAT file system volume cannot be moved.
When possible, move data in blocks aligned relative to each other in 16-kilobyte (KB) increments. This reduces copy-on-write overhead when shadow copies are enabled, because shadow copy space is increased and performance is reduced when the following conditions occur:
The move delta is the number of bytes between the start of the source block and the start of the target block. In other words, a block starting at offset X (on-disk) can be moved to a starting offset Y if the absolute value of X minus Y is an even multiple of 16 KB. So, assuming 4-KB clusters, a move from cluster 3 to cluster 27 will be optimized, but a move from cluster 18 to cluster 24 will not. Note that mod(3,4) = 3 = mod(27,4). Mod 4 is chosen because four clusters at 4 KB each is equivalent to 16 KB. Therefore, a volume formatted to a 16-KB cluster size will result in all move files being optimized.
For more information about shadow copies, see Volume Shadow Copy Service.