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FsRtlLookupLastLargeMcbEntry routine

The FsRtlLookupLastLargeMcbEntry routine retrieves the last mapping entry stored in the map control block (MCB).

Syntax


BOOLEAN FsRtlLookupLastLargeMcbEntry(
  _In_   PLARGE_MCB OpaqueMcb,
  _Out_  PLONGLONG LargeVbn,
  _Out_  PLONGLONG LargeLbn
);

Parameters

OpaqueMcb [in]

Pointer to an initialized MCB structure to be searched.

LargeVbn [out]

Pointer to a variable that receives the last virtual block number (VBN) that was mapped.

LargeLbn [out]

Pointer to a variable that receives the logical block number (LBN) that is mapped to the VBN pointed to by LargeVbn, or -1 if no such LBN exists.

Return value

FsRtlLookupLastLargeMcbEntry returns FALSE if the MCB contains no mapping entries, TRUE otherwise.

Remarks

FsRtlLookupLastLargeMcbEntry searches for the last mapping of the last run in the MCB:

  • If the MCB contains no mappings, FsRtlLookupLastLargeMcbEntry returns FALSE.

  • If the last mapping is a hole, FsRtlLookupLastLargeMcbEntry returns TRUE, but the lookup operation yields a value of -1 for the LBN.

  • If the last mapping is not a hole, the lookup operation yields a positive value for the LBN, and FsRtlLookupLastLargeMcbEntry returns TRUE.

Note   The upper 32 bits of the LBN are ignored. Only the lower 32 bits are used.

Requirements

Header

Ntifs.h (include Ntifs.h)

Library

Ntoskrnl.lib

IRQL

<= APC_LEVEL

See also

FsRtlAddLargeMcbEntry
FsRtlGetNextLargeMcbEntry
FsRtlInitializeLargeMcb
FsRtlLookupLargeMcbEntry
FsRtlLookupLastLargeMcbEntryAndIndex
FsRtlNumberOfRunsInLargeMcb
FsRtlRemoveLargeMcbEntry
FsRtlSplitLargeMcb
FsRtlTruncateLargeMcb
FsRtlUninitializeLargeMcb

 

 

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