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FSCTL_SET_ZERO_DATA control code

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The FSCTL_SET_ZERO_DATA control code fills a specified range of a file with zeros (0). If the file is sparse or compressed, the NTFS file system may deallocate disk space in the file. This sets the range of bytes to zeros (0) without extending the file size.

To perform this operation from a driver, call FltFsControlFile with the following parameters.

Parameters

  • Instance: Opaque instance pointer for the caller. This parameter is required and cannot be NULL.

  • FileObject [in]: File object pointer to the file in which to write zeros to. This parameter is required and cannot be NULL.

  • FsControlCode [in]: The control code for the operation.

Use FSCTL_SET_ZERO_DATA for this operation.

The FileOffset member is the byte offset of the first byte to set to zeros (0), and the BeyondFinalZero member is the byte offset of the first byte beyond the last zero (0) byte.

The Flags member in FILE_ZERO_DATA_INFORMATION_EX specifies modifiers to the operation. For example, when Flags is set to FILE_ZERO_DATA_INFORMATION_FLAG_PRESERVE_CACHED_DATA, the contents of the cache corresponding to this range of the file are not purged.

  • InputBufferLength [in]: The size of the input buffer, in bytes.

  • OutputBuffer [out]: Not used with this operation; set to NULL.

  • OutputBufferLength [out]: Not used with this operation; set to zero.

Status block

FltFsControlFile returns STATUS_SUCCESS or an appropriate NTSTATUS value.

Return code Meaning
STATUS _INSUFFICIENT_RESOURCES There is not enough memory to complete the operation.
STATUS_INVALID_PARAMETER The InputBufferLength is smaller than the size of the FILE_ZERO_DATA_INFORMATION structures or the file specified is a system metadata file or a directory.
STATUS_ACCESS_DENIED The FILE_ZERO_DATA_INFORMATION_FLAG_PRESERVE_CACHED_DATA is set from user mode.
STATUS_MEDIA_WRITE_PROTECTED The volume is currently write protected.

Requirements

Requirement type Requirement
Header Ntifs.h (include Ntifs.h)

See also

FltFsControlFile

FILE_ZERO_DATA_INFORMATION

FILE_ZERO_DATA_INFORMATION_EX