FsRtlQueryKernelEaFile routine

Article
01/08/2018

The routine FsRtlQueryKernelEaFile is used to build an explicit QueryEA request and synchronously wait for it to complete, returning the result. This allows the caller to do this by FileObject instead of a handle.

Syntax

NTSTATUS FsRtlQueryKernelEaFile(
  _In_      PFILE_OBJECT                              FileObject,
  _Out_     bcount_part(Length,*LengthReturned) PVOID ReturnedEaData,
  _In_      ULONG                                     Length,
  _In_      BOOLEAN                                   ReturnSingleEntry,
  _In_      bcount_opt(EaListLength) PVOID            EaList,
  _In_      ULONG                                     EaListLength,
  _In_opt_  PULONG                                    EaIndex,
  _In_      BOOLEAN                                   RestartScan,
  _Out_opt_ PULONG                                    LengthReturned
);

Parameters

FileObject [in]
A pointer to a FileObject to send the QueryEA request to.
ReturnedEaData [out]
A pointer to a caller-supplied FILE_FULL_EA_INFORMATION-structured output buffer, where the extended attribute values are to be returned.
Length [in]
Specifies the length, in bytes, of ReturnedEaData
ReturnSingleEntry [in]
Specifies whether only a single entry should be returned rather than filling the buffer with as many EAs as possible.
EaList [in]
A pointer to a caller-supplied FILE_GET_EA_INFORMATION-structured input buffer, which specifies the extended attributes to be queried. This parameter is optional and can be NULL.
EaListLength [in]
Specifies the length of EaList, if an EA list was supplied.
EaIndex [in, optional]
Supplies the optional index of an EA whose value is to be returned. If specified, then only that EA is returned.
RestartScan [in]
Specifies whether the scan of the EAs should be restarted from the beginning.
LengthReturned [out, optional]
Specifies the amount of valid data that is returned in the ReturnedEaData buffer.

Return value

The routine FsRtlQueryKernelEaFile returns one of the status codes:

Return code	Description
STATUS_EAS_NOT_SUPPORTED	The file system does not support extended attributes.
STATUS_INVALID_DEVICE_REQUEST	The request failed as it was a direct device open.
STATUS_INSUFFICIENT_RESOURCES	The I/O request packet (IRP) could not be allocated for this request.
STATUS_SUCCESS	The request was successful.

Remarks

This routine FsRtlQueryKernelEaFile assumes all passed in buffers are from kernel mode as it requires that the given Input and Output buffers if specified, be kernel mode addresses. The operation will fail if a user mode address is specified.

Requirements

Minimum supported client	Windows 8
Minimum supported server	Windows Server 2012
Header	Ntifs.h

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