IO_STACK_LOCATION structure
Download EaseFilter Filter Driver SDK Setup File Download EaseFilter Filter Driver SDK Zip File
Syntax
typedef struct _IO_STACK_LOCATION {
UCHAR MajorFunction;
UCHAR MinorFunction;
UCHAR Flags;
UCHAR Control;
union {
struct {
PIO_SECURITY_CONTEXT SecurityContext;
ULONG Options;
USHORT POINTER_ALIGNMENT FileAttributes;
USHORT ShareAccess;
ULONG POINTER_ALIGNMENT EaLength;
} Create;
struct {
PIO_SECURITY_CONTEXT SecurityContext;
ULONG Options;
USHORT POINTER_ALIGNMENT Reserved;
USHORT ShareAccess;
PNAMED_PIPE_CREATE_PARAMETERS Parameters;
} CreatePipe;
struct {
PIO_SECURITY_CONTEXT SecurityContext;
ULONG Options;
USHORT POINTER_ALIGNMENT Reserved;
USHORT ShareAccess;
PMAILSLOT_CREATE_PARAMETERS Parameters;
} CreateMailslot;
struct {
ULONG Length;
ULONG POINTER_ALIGNMENT Key;
ULONG Flags;
LARGE_INTEGER ByteOffset;
} Read;
struct {
ULONG Length;
ULONG POINTER_ALIGNMENT Key;
ULONG Flags;
LARGE_INTEGER ByteOffset;
} Write;
struct {
ULONG Length;
PUNICODE_STRING FileName;
FILE_INFORMATION_CLASS FileInformationClass;
ULONG POINTER_ALIGNMENT FileIndex;
} QueryDirectory;
struct {
ULONG Length;
ULONG POINTER_ALIGNMENT CompletionFilter;
} NotifyDirectory;
struct {
ULONG Length;
ULONG POINTER_ALIGNMENT CompletionFilter;
DIRECTORY_NOTIFY_INFORMATION_CLASS POINTER_ALIGNMENT DirectoryNotifyInformationClass;
} NotifyDirectoryEx;
struct {
ULONG Length;
FILE_INFORMATION_CLASS POINTER_ALIGNMENT FileInformationClass;
} QueryFile;
struct {
ULONG Length;
FILE_INFORMATION_CLASS POINTER_ALIGNMENT FileInformationClass;
PFILE_OBJECT FileObject;
union {
struct {
BOOLEAN ReplaceIfExists;
BOOLEAN AdvanceOnly;
};
ULONG ClusterCount;
HANDLE DeleteHandle;
};
} SetFile;
struct {
ULONG Length;
PVOID EaList;
ULONG EaListLength;
ULONG POINTER_ALIGNMENT EaIndex;
} QueryEa;
struct {
ULONG Length;
} SetEa;
struct {
ULONG Length;
FS_INFORMATION_CLASS POINTER_ALIGNMENT FsInformationClass;
} QueryVolume;
struct {
ULONG Length;
FS_INFORMATION_CLASS POINTER_ALIGNMENT FsInformationClass;
} SetVolume;
struct {
ULONG OutputBufferLength;
ULONG POINTER_ALIGNMENT InputBufferLength;
ULONG POINTER_ALIGNMENT FsControlCode;
PVOID Type3InputBuffer;
} FileSystemControl;
struct {
PLARGE_INTEGER Length;
ULONG POINTER_ALIGNMENT Key;
LARGE_INTEGER ByteOffset;
} LockControl;
struct {
ULONG OutputBufferLength;
ULONG POINTER_ALIGNMENT InputBufferLength;
ULONG POINTER_ALIGNMENT IoControlCode;
PVOID Type3InputBuffer;
} DeviceIoControl;
struct {
SECURITY_INFORMATION SecurityInformation;
ULONG POINTER_ALIGNMENT Length;
} QuerySecurity;
struct {
SECURITY_INFORMATION SecurityInformation;
PSECURITY_DESCRIPTOR SecurityDescriptor;
} SetSecurity;
struct {
PVPB Vpb;
PDEVICE_OBJECT DeviceObject;
} MountVolume;
struct {
PVPB Vpb;
PDEVICE_OBJECT DeviceObject;
} VerifyVolume;
struct {
struct _SCSI_REQUEST_BLOCK *Srb;
} Scsi;
struct {
ULONG Length;
PSID StartSid;
PFILE_GET_QUOTA_INFORMATION SidList;
ULONG SidListLength;
} QueryQuota;
struct {
ULONG Length;
} SetQuota;
struct {
DEVICE_RELATION_TYPE Type;
} QueryDeviceRelations;
struct {
const GUID *InterfaceType;
USHORT Size;
USHORT Version;
PINTERFACE Interface;
PVOID InterfaceSpecificData;
} QueryInterface;
struct {
PDEVICE_CAPABILITIES Capabilities;
} DeviceCapabilities;
struct {
PIO_RESOURCE_REQUIREMENTS_LIST IoResourceRequirementList;
} FilterResourceRequirements;
struct {
ULONG WhichSpace;
PVOID Buffer;
ULONG Offset;
ULONG POINTER_ALIGNMENT Length;
} ReadWriteConfig;
struct {
BOOLEAN Lock;
} SetLock;
struct {
BUS_QUERY_ID_TYPE IdType;
} QueryId;
struct {
DEVICE_TEXT_TYPE DeviceTextType;
LCID POINTER_ALIGNMENT LocaleId;
} QueryDeviceText;
struct {
BOOLEAN InPath;
BOOLEAN Reserved[3];
DEVICE_USAGE_NOTIFICATION_TYPE POINTER_ALIGNMENT Type;
} UsageNotification;
struct {
SYSTEM_POWER_STATE PowerState;
} WaitWake;
struct {
PPOWER_SEQUENCE PowerSequence;
} PowerSequence;
#if ...
struct {
union {
ULONG SystemContext;
SYSTEM_POWER_STATE_CONTEXT SystemPowerStateContext;
};
POWER_STATE_TYPE POINTER_ALIGNMENT Type;
POWER_STATE POINTER_ALIGNMENT State;
POWER_ACTION POINTER_ALIGNMENT ShutdownType;
} Power;
#else
struct {
ULONG SystemContext;
POWER_STATE_TYPE POINTER_ALIGNMENT Type;
POWER_STATE POINTER_ALIGNMENT State;
POWER_ACTION POINTER_ALIGNMENT ShutdownType;
} Power;
#endif
struct {
PCM_RESOURCE_LIST AllocatedResources;
PCM_RESOURCE_LIST AllocatedResourcesTranslated;
} StartDevice;
struct {
ULONG_PTR ProviderId;
PVOID DataPath;
ULONG BufferSize;
PVOID Buffer;
} WMI;
struct {
PVOID Argument1;
PVOID Argument2;
PVOID Argument3;
PVOID Argument4;
} Others;
} Parameters;
PDEVICE_OBJECT DeviceObject;
PFILE_OBJECT FileObject;
PIO_COMPLETION_ROUTINE CompletionRoutine;
PVOID Context;
} IO_STACK_LOCATION, *PIO_STACK_LOCATION;
Members
MajorFunction
The IRP major function code indicating the type of I/O operation to be performed.
MinorFunction
A subfunction code for MajorFunction. The PnP manager, the power manager, file system drivers, and SCSI class drivers set this member for some requests.
Flags
Request-type-specific values used almost exclusively by file system drivers. Removable-media device drivers check whether this member is set with SL_OVERRIDE_VERIFY_VOLUME for read requests to determine whether to continue the read operation even if the device object's Flags is set with DO_VERIFY_VOLUME. Intermediate drivers layered over a removable-media device driver must copy this member into the I/O stack location of the next-lower driver in all incoming IRP_MJ_READ requests.
Possible flag values include:
| Flag | Value | Description |
|---|---|---|
| SL_KEY_SPECIFIED | 0x01 | Indicates that the IO_STACK_LOCATION.Parameters.Read(OrWrite).Key contains which copy of a given sector should be read when redundancy is enabled. Today this flag is use only with IRP_MJ_READ operations. |
| SL_OVERRIDE_VERIFY_VOLUME | 0x02 | This flag is used to determine whether to continue the read operation even if the device object's Flags is set with DO_VERIFY_VOLUME. |
| SL_WRITE_THROUGH | 0x04 | This flag informs the storage driver to set appropriate flags so that the disk bypasses the write cache in order to force the disk to write through to its persistent storage media. This flag is device-specific; not all disk drives support bypassing disk-cache. |
| SL_FT_SEQUENTIAL_WRITE | 0x08 | Reserved for system use. |
| SL_FORCE_DIRECT_WRITE | 0x10 | This flag lets kernel-mode drivers write to volume areas that they normally cannot write to because of blocking direct write in the file system and storage driver stack. This flag was introduced in Windows Vista.
Note Direct write blocking, introduced in Windows Vista helps improve security. This flag is checked both at the file system layer and storage stack layer. For more information about direct write blocking, see Blocking Direct Write Operations to Volumes and Disks.
|
| SL_REALTIME_STREAM | 0x20 | This flag hints that the IO is for real-time streaming requests to a CD-ROM class driver. This hints the driver to perform READ/WRITE operations at a guaranteed speed for real-time streaming. This flag is valid only with optical media. |
| SL_PERSISTENT_MEMORY_FIXED_MAPPING | 0x20 | The persistent memory mapping of the bytes in the write request cannot change while handling this write request. This flag is valid only with a persistent memory device and IRP_MJ_WRITE. |
Note (For persistent memory devices) One of the reasons for remapping (modifying the physical address of a given LBA) on persistent memory devices is to provide efficient sector level atomicity. If the flag is not set, remapping is allowed especially if it results in the driver providing sector atomicity. File systems (or the requester) prefer that a persistent memory device driver provides sector atomicity. If the flag is set, a persistent memory driver shall not remap the physical addresses corresponding to the LBAs. If that means sector atomicity can't be provided, so be it. However, the driver is more than welcome to provide sector atomicity as long as there is no remapping.
Control
Drivers can check this member to determine whether it is set with SL_PENDING_RETURNED. Drivers have read-only access to this member.