IRP_MJ_SET_VOLUME_INFORMATION (FS and filter drivers)
When Sent
The I/O Manager sends the IRP_MJ_SET_VOLUME_INFORMATION request. It can be sent, for example, when a user-mode application has called a Win32 function such as SetVolumeLabel.
Operation: File System Drivers
The file system driver should extract and decode the file object to determine whether it represents a user volume open. If it does, the file system driver should set the appropriate volume information and complete the IRP. Otherwise, the file system should complete the IRP as appropriate without setting the volume information.
The types of volume information that can be set are file system-dependent, but generally include one or more of the following values:
- FileFsControlInformation
- FileFsLabelInformation
- FileFsObjectIdInformation
For a list of all possible information types, see the FS_INFORMATION_CLASS enumeration in ntifs.h.
Operation: Legacy File System Filter Drivers
The filter driver should pass this IRP down to the next-lower driver on the stack.
Parameters
A file system or filter driver calls IoGetCurrentIrpStackLocation for the given IRP to get a pointer to its own stack location in the IRP. In the following parameters, Irp points to the IRP and IrpSp points to the IO_STACK_LOCATION. The driver can use the information that is set in the following members of the IRP and the IRP stack location to process a set volume information request:
DeviceObject is a pointer to the target device object.
Irp->AssociatedIrp.SystemBuffer points to an input buffer that contains the values of the volume information to be set. This information is stored in one of the following structures:
- FILE_FS_CONTROL_INFORMATION
- FILE_FS_LABEL_INFORMATION
- FILE_FS_OBJECTID_INFORMATION
Irp->IoStatus points to an IO_STATUS_BLOCK structure that receives the final completion status and information about the requested operation.
IrpSp->FileObject points to the file object that is associated with DeviceObject.
The IrpSp->FileObject parameter contains a pointer to the RelatedFileObject field, which is also a FILE_OBJECT structure. The RelatedFileObject field of the FILE_OBJECT structure isn't valid during the processing of IRP_MJ_SET_VOLUME_INFORMATION and shouldn't be used.
IrpSp->MajorFunction is set to IRP_MJ_SET_VOLUME_INFORMATION.
IrpSp->Parameters.SetVolume.FsInformationClass is the type of information to be set for the volume, and can be one of the following:
Value Meaning FileFsControlInformation Set FILE_FS_CONTROL_INFORMATION for the volume. FileFsLabelInformation Set FILE_FS_LABEL_INFORMATION for the volume. FileFsObjectIdInformation Set FILE_FS_OBJECTID_INFORMATION for the volume. IrpSp->Parameters.SetVolume.Length is the length, in bytes, of the buffer pointed to by Irp->AssociatedIrp.SystemBuffer.