FsRtlLookupLastLargeMcbEntry function (ntifs.h)

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

Syntax

BOOLEAN FsRtlLookupLastLargeMcbEntry(
  PLARGE_MCB Mcb,
  PLONGLONG  Vbn,
  PLONGLONG  Lbn
);

Mcb

Pointer to an initialized MCB structure to be searched.

Vbn

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

Lbn

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.

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

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.

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