[UDFS] Use LONG for reference/counter fields to eliminate Interlocked casts and fix mixed sign-type comparisons

[Copilot]

Counter and reference fields in the UDFS driver were declared as ULONG/uint32 despite being used exclusively with signed Interlocked operations, requiring pervasive (PLONG)/(int32*) casts at every call site. More critically, companion fields (FcbCleanup, VcbResidualReference, etc.) remained ULONG while their siblings were already signed, producing mixed signed/unsigned comparisons.

Field type changes

struct.h — changed ULONG/uint32 → LONG:

• FCB: FcbReference, FcbCleanup, CachedOpenHandleCount, FcbUserReference
• VCB: VcbReference, VcbCleanup, VcbUserReference, VcbResidualReference, VcbResidualUserReference
• Misc: Modified, numFiles, numDirs, CcbCount

udf_info/udf_rel.h — changed uint32 → LONG:

• UDF_FILE_INFO::RefCount, OpenCount
• UDF_DATALOC_INFO::LinkRefCount

Cast removal

With correct field types, all (PLONG) / (int32*) casts are removed from ~60 InterlockedIncrement/InterlockedDecrement/InterlockedExchangeAdd call sites across 9 files.

// Before
InterlockedIncrement((PLONG)&Vcb->VcbReference);
InterlockedDecrement((int32*)counter);

// After
InterlockedIncrement(&Vcb->VcbReference);
InterlockedDecrement(counter);

Bug fix: mixed signed/unsigned comparisons

Mismatched types between LONG reference fields and their ULONG companions caused implicit sign-to-unsigned conversions in comparisons. A negative value (indicating an over-release bug) would silently appear as a large positive number and pass assertions:

Expression	Before	After
FcbCleanup <= (FcbReference - 1)	ULONG <= LONG ⚠️	LONG <= LONG ✅
VcbReference -= VcbResidualReference	LONG -= ULONG ⚠️	LONG -= LONG ✅
VcbReference <= VcbResidualReference	LONG <= ULONG ⚠️	LONG <= LONG ✅

Original prompt

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This section details on the original issue you should resolve

<issue_title>[UDFS] Is there any benefit to simplifying the usage of the Interlocked functions that it uses?</issue_title>
<issue_description></issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [UDFS] Is there any benefit to simplifying the usage of the Interlocked functions that it uses? #113

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