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5292 lines
158 KiB
C
5292 lines
158 KiB
C
/*++
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Copyright (c) 1990-2000 Microsoft Corporation
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Module Name:
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AllocSup.c
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Abstract:
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This module implements the Allocation support routines for Fat.
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--*/
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#include "fatprocs.h"
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//
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// The Bug check file id for this module
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//
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#define BugCheckFileId (FAT_BUG_CHECK_ALLOCSUP)
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//
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// Local debug trace level
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//
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#define Dbg (DEBUG_TRACE_ALLOCSUP)
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#define FatMin(a, b) ((a) < (b) ? (a) : (b))
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//
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// Define prefetch page count for the FAT
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//
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#define FAT_PREFETCH_PAGE_COUNT 0x100
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//
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// Local support routine prototypes
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//
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VOID
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FatLookupFatEntry(
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IN PIRP_CONTEXT IrpContext,
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IN PVCB Vcb,
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IN ULONG FatIndex,
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IN OUT PULONG FatEntry,
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IN OUT PFAT_ENUMERATION_CONTEXT Context
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);
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VOID
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FatSetFatRun(
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IN PIRP_CONTEXT IrpContext,
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IN PVCB Vcb,
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IN ULONG StartingFatIndex,
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IN ULONG ClusterCount,
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IN BOOLEAN ChainTogether
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);
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UCHAR
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FatLogOf(
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IN ULONG Value
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);
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//
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// Note that the KdPrint below will ONLY fire when the assert does. Leave it
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// alone.
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//
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#if DBG
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#define ASSERT_CURRENT_WINDOW_GOOD(VCB) { \
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ULONG FreeClusterBitMapClear; \
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NT_ASSERT( (VCB)->FreeClusterBitMap.Buffer != NULL ); \
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FreeClusterBitMapClear = RtlNumberOfClearBits(&(VCB)->FreeClusterBitMap); \
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if ((VCB)->CurrentWindow->ClustersFree != FreeClusterBitMapClear) { \
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KdPrint(("FAT: ClustersFree %x h != FreeClusterBitMapClear %x h\n", \
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(VCB)->CurrentWindow->ClustersFree, \
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FreeClusterBitMapClear)); \
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} \
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NT_ASSERT( (VCB)->CurrentWindow->ClustersFree == FreeClusterBitMapClear ); \
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}
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#else
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#define ASSERT_CURRENT_WINDOW_GOOD(VCB)
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#endif
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//
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// The following macros provide a convenient way of hiding the details
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// of bitmap allocation schemes.
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//
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//
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// VOID
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// FatLockFreeClusterBitMap (
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// IN PVCB Vcb
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// );
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//
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#define FatLockFreeClusterBitMap(VCB) { \
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NT_ASSERT(KeAreApcsDisabled()); \
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ExAcquireFastMutexUnsafe( &(VCB)->FreeClusterBitMapMutex ); \
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ASSERT_CURRENT_WINDOW_GOOD(VCB) \
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}
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//
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// VOID
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// FatUnlockFreeClusterBitMap (
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// IN PVCB Vcb
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// );
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//
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#define FatUnlockFreeClusterBitMap(VCB) { \
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ASSERT_CURRENT_WINDOW_GOOD(VCB) \
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NT_ASSERT(KeAreApcsDisabled()); \
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ExReleaseFastMutexUnsafe( &(VCB)->FreeClusterBitMapMutex ); \
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}
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//
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// BOOLEAN
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// FatIsClusterFree (
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// IN PIRP_CONTEXT IrpContext,
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// IN PVCB Vcb,
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// IN ULONG FatIndex
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// );
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//
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#define FatIsClusterFree(IRPCONTEXT,VCB,FAT_INDEX) \
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(RtlCheckBit(&(VCB)->FreeClusterBitMap,(FAT_INDEX)-2) == 0)
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//
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// VOID
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// FatFreeClusters (
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// IN PIRP_CONTEXT IrpContext,
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// IN PVCB Vcb,
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// IN ULONG FatIndex,
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// IN ULONG ClusterCount
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// );
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//
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#define FatFreeClusters(IRPCONTEXT,VCB,FAT_INDEX,CLUSTER_COUNT) { \
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if ((CLUSTER_COUNT) == 1) { \
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FatSetFatEntry((IRPCONTEXT),(VCB),(FAT_INDEX),FAT_CLUSTER_AVAILABLE); \
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} else { \
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FatSetFatRun((IRPCONTEXT),(VCB),(FAT_INDEX),(CLUSTER_COUNT),FALSE); \
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} \
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}
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//
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// VOID
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// FatAllocateClusters (
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// IN PIRP_CONTEXT IrpContext,
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// IN PVCB Vcb,
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// IN ULONG FatIndex,
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// IN ULONG ClusterCount
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// );
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//
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#define FatAllocateClusters(IRPCONTEXT,VCB,FAT_INDEX,CLUSTER_COUNT) { \
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if ((CLUSTER_COUNT) == 1) { \
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FatSetFatEntry((IRPCONTEXT),(VCB),(FAT_INDEX),FAT_CLUSTER_LAST); \
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} else { \
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FatSetFatRun((IRPCONTEXT),(VCB),(FAT_INDEX),(CLUSTER_COUNT),TRUE); \
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} \
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}
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//
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// VOID
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// FatUnreserveClusters (
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// IN PIRP_CONTEXT IrpContext,
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// IN PVCB Vcb,
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// IN ULONG FatIndex,
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// IN ULONG ClusterCount
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// );
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//
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#define FatUnreserveClusters(IRPCONTEXT,VCB,FAT_INDEX,CLUSTER_COUNT) { \
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NT_ASSERT( (FAT_INDEX) + (CLUSTER_COUNT) - 2 <= (VCB)->FreeClusterBitMap.SizeOfBitMap );\
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NT_ASSERT( (FAT_INDEX) >= 2); \
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RtlClearBits(&(VCB)->FreeClusterBitMap,(FAT_INDEX)-2,(CLUSTER_COUNT)); \
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if ((FAT_INDEX) < (VCB)->ClusterHint) { \
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(VCB)->ClusterHint = (FAT_INDEX); \
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} \
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}
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//
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// VOID
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// FatReserveClusters (
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// IN PIRP_CONTEXT IrpContext,
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// IN PVCB Vcb,
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// IN ULONG FatIndex,
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// IN ULONG ClusterCount
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// );
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//
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// Handle wrapping the hint back to the front.
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//
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#define FatReserveClusters(IRPCONTEXT,VCB,FAT_INDEX,CLUSTER_COUNT) { \
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ULONG _AfterRun = (FAT_INDEX) + (CLUSTER_COUNT); \
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NT_ASSERT( (FAT_INDEX) + (CLUSTER_COUNT) - 2 <= (VCB)->FreeClusterBitMap.SizeOfBitMap );\
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NT_ASSERT( (FAT_INDEX) >= 2); \
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RtlSetBits(&(VCB)->FreeClusterBitMap,(FAT_INDEX)-2,(CLUSTER_COUNT)); \
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\
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if (_AfterRun - 2 >= (VCB)->FreeClusterBitMap.SizeOfBitMap) { \
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_AfterRun = 2; \
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} \
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if (RtlCheckBit(&(VCB)->FreeClusterBitMap, _AfterRun - 2)) { \
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(VCB)->ClusterHint = RtlFindClearBits( &(VCB)->FreeClusterBitMap, 1, _AfterRun - 2) + 2; \
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if (1 == (VCB)->ClusterHint) { \
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(VCB)->ClusterHint = 2; \
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} \
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} \
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else { \
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(VCB)->ClusterHint = _AfterRun; \
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} \
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}
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//
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// ULONG
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// FatFindFreeClusterRun (
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// IN PIRP_CONTEXT IrpContext,
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// IN PVCB Vcb,
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// IN ULONG ClusterCount,
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// IN ULONG AlternateClusterHint
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// );
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//
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// Do a special check if only one cluster is desired.
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//
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#define FatFindFreeClusterRun(IRPCONTEXT,VCB,CLUSTER_COUNT,CLUSTER_HINT) ( \
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(CLUSTER_COUNT == 1) && \
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FatIsClusterFree((IRPCONTEXT), (VCB), (CLUSTER_HINT)) ? \
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(CLUSTER_HINT) : \
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RtlFindClearBits( &(VCB)->FreeClusterBitMap, \
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(CLUSTER_COUNT), \
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(CLUSTER_HINT) - 2) + 2 \
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)
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//
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// FAT32: Define the maximum size of the FreeClusterBitMap to be the
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// maximum size of a FAT16 FAT. If there are more clusters on the
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// volume than can be represented by this many bytes of bitmap, the
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// FAT will be split into "buckets", each of which does fit.
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//
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// Note this count is in clusters/bits of bitmap.
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//
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#define MAX_CLUSTER_BITMAP_SIZE (1 << 16)
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//
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// Calculate the window a given cluster number is in.
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//
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#define FatWindowOfCluster(C) (((C) - 2) / MAX_CLUSTER_BITMAP_SIZE)
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#ifdef ALLOC_PRAGMA
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#pragma alloc_text(PAGE, FatAddFileAllocation)
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#pragma alloc_text(PAGE, FatAllocateDiskSpace)
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#pragma alloc_text(PAGE, FatDeallocateDiskSpace)
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#pragma alloc_text(PAGE, FatExamineFatEntries)
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#pragma alloc_text(PAGE, FatInterpretClusterType)
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#pragma alloc_text(PAGE, FatLogOf)
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#pragma alloc_text(PAGE, FatLookupFatEntry)
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#pragma alloc_text(PAGE, FatLookupFileAllocation)
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#pragma alloc_text(PAGE, FatLookupFileAllocationSize)
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#pragma alloc_text(PAGE, FatMergeAllocation)
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#pragma alloc_text(PAGE, FatSetFatEntry)
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#pragma alloc_text(PAGE, FatSetFatRun)
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#pragma alloc_text(PAGE, FatSetupAllocationSupport)
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#pragma alloc_text(PAGE, FatSplitAllocation)
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#pragma alloc_text(PAGE, FatTearDownAllocationSupport)
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#pragma alloc_text(PAGE, FatTruncateFileAllocation)
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#endif
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INLINE
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ULONG
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FatSelectBestWindow(
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IN PVCB Vcb
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)
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/*++
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Routine Description:
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Choose a window to allocate clusters from. Order of preference is:
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1. First window with >50% free clusters
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2. First empty window
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3. Window with greatest number of free clusters.
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Arguments:
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Vcb - Supplies the Vcb for the volume
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Return Value:
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'Best window' number (index into Vcb->Windows[])
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--*/
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{
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ULONG i, Fave = 0;
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ULONG MaxFree = 0;
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ULONG FirstEmpty = (ULONG)-1;
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ULONG ClustersPerWindow = MAX_CLUSTER_BITMAP_SIZE;
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NT_ASSERT( 1 != Vcb->NumberOfWindows);
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for (i = 0; i < Vcb->NumberOfWindows; i++) {
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if (Vcb->Windows[i].ClustersFree == ClustersPerWindow) {
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if (-1 == FirstEmpty) {
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//
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// Keep note of the first empty window on the disc
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//
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FirstEmpty = i;
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}
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}
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else if (Vcb->Windows[i].ClustersFree > MaxFree) {
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//
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// This window has the most free clusters, so far
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//
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MaxFree = Vcb->Windows[i].ClustersFree;
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Fave = i;
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//
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// If this window has >50% free clusters, then we will take it,
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// so don't bother considering more windows.
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//
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if (MaxFree >= (ClustersPerWindow >> 1)) {
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break;
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}
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}
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}
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//
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// If there were no windows with 50% or more freespace, then select the
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// first empty window on the disc, if any - otherwise we'll just go with
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// the one with the most free clusters.
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//
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if ((MaxFree < (ClustersPerWindow >> 1)) && (-1 != FirstEmpty)) {
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Fave = FirstEmpty;
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}
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return Fave;
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}
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VOID
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FatSetupAllocationSupport (
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IN PIRP_CONTEXT IrpContext,
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IN PVCB Vcb
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)
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/*++
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Routine Description:
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This routine fills in the Allocation Support structure in the Vcb.
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Most entries are computed using fat.h macros supplied with data from
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the Bios Parameter Block. The free cluster count, however, requires
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going to the Fat and actually counting free sectors. At the same time
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the free cluster bit map is initalized.
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Arguments:
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Vcb - Supplies the Vcb to fill in.
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--*/
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{
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ULONG BitIndex;
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ULONG ClustersDescribableByFat;
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PAGED_CODE();
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DebugTrace(+1, Dbg, "FatSetupAllocationSupport\n", 0);
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DebugTrace( 0, Dbg, " Vcb = %p\n", Vcb);
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//
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// Compute a number of fields for Vcb.AllocationSupport
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//
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Vcb->AllocationSupport.RootDirectoryLbo = FatRootDirectoryLbo( &Vcb->Bpb );
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Vcb->AllocationSupport.RootDirectorySize = FatRootDirectorySize( &Vcb->Bpb );
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Vcb->AllocationSupport.FileAreaLbo = FatFileAreaLbo( &Vcb->Bpb );
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Vcb->AllocationSupport.NumberOfClusters = FatNumberOfClusters( &Vcb->Bpb );
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Vcb->AllocationSupport.FatIndexBitSize = FatIndexBitSize( &Vcb->Bpb );
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Vcb->AllocationSupport.LogOfBytesPerSector = FatLogOf(Vcb->Bpb.BytesPerSector);
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Vcb->AllocationSupport.LogOfBytesPerCluster = FatLogOf(FatBytesPerCluster( &Vcb->Bpb ));
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Vcb->AllocationSupport.NumberOfFreeClusters = 0;
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//
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// Deal with a bug in DOS 5 format, if the Fat is not big enough to
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// describe all the clusters on the disk, reduce this number. We expect
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// that fat32 volumes will not have this problem.
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//
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// Turns out this was not a good assumption. We have to do this always now.
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//
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ClustersDescribableByFat = ( ((FatIsFat32(Vcb)? Vcb->Bpb.LargeSectorsPerFat :
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Vcb->Bpb.SectorsPerFat) *
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Vcb->Bpb.BytesPerSector * 8)
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/ FatIndexBitSize(&Vcb->Bpb) ) - 2;
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if (Vcb->AllocationSupport.NumberOfClusters > ClustersDescribableByFat) {
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Vcb->AllocationSupport.NumberOfClusters = ClustersDescribableByFat;
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}
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//
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// Extend the virtual volume file to include the Fat
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//
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{
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CC_FILE_SIZES FileSizes;
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FileSizes.AllocationSize.QuadPart =
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FileSizes.FileSize.QuadPart = (FatReservedBytes( &Vcb->Bpb ) +
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FatBytesPerFat( &Vcb->Bpb ));
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FileSizes.ValidDataLength = FatMaxLarge;
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if ( Vcb->VirtualVolumeFile->PrivateCacheMap == NULL ) {
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FatInitializeCacheMap( Vcb->VirtualVolumeFile,
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&FileSizes,
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TRUE,
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&FatData.CacheManagerNoOpCallbacks,
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Vcb );
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} else {
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CcSetFileSizes( Vcb->VirtualVolumeFile, &FileSizes );
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}
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}
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_SEH2_TRY {
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if (FatIsFat32(Vcb) &&
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Vcb->AllocationSupport.NumberOfClusters > MAX_CLUSTER_BITMAP_SIZE) {
|
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Vcb->NumberOfWindows = (Vcb->AllocationSupport.NumberOfClusters +
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MAX_CLUSTER_BITMAP_SIZE - 1) /
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MAX_CLUSTER_BITMAP_SIZE;
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|
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} else {
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Vcb->NumberOfWindows = 1;
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}
|
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|
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Vcb->Windows = FsRtlAllocatePoolWithTag( PagedPool,
|
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Vcb->NumberOfWindows * sizeof(FAT_WINDOW),
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TAG_FAT_WINDOW );
|
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|
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RtlInitializeBitMap( &Vcb->FreeClusterBitMap,
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NULL,
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0 );
|
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|
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//
|
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// Chose a FAT window to begin operation in.
|
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//
|
||
|
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if (Vcb->NumberOfWindows > 1) {
|
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|
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//
|
||
// Read the fat and count up free clusters. We bias by the two reserved
|
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// entries in the FAT.
|
||
//
|
||
|
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FatExamineFatEntries( IrpContext, Vcb,
|
||
2,
|
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Vcb->AllocationSupport.NumberOfClusters + 2 - 1,
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TRUE,
|
||
NULL,
|
||
NULL);
|
||
|
||
|
||
//
|
||
// Pick a window to begin allocating from
|
||
//
|
||
|
||
Vcb->CurrentWindow = &Vcb->Windows[ FatSelectBestWindow( Vcb)];
|
||
|
||
} else {
|
||
|
||
Vcb->CurrentWindow = &Vcb->Windows[0];
|
||
|
||
//
|
||
// Carefully bias ourselves by the two reserved entries in the FAT.
|
||
//
|
||
|
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Vcb->CurrentWindow->FirstCluster = 2;
|
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Vcb->CurrentWindow->LastCluster = Vcb->AllocationSupport.NumberOfClusters + 2 - 1;
|
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}
|
||
|
||
//
|
||
// Now transition to the FAT window we have chosen.
|
||
//
|
||
|
||
FatExamineFatEntries( IrpContext, Vcb,
|
||
0,
|
||
0,
|
||
FALSE,
|
||
Vcb->CurrentWindow,
|
||
NULL);
|
||
|
||
//
|
||
// Now set the ClusterHint to the first free bit in our favorite
|
||
// window (except the ClusterHint is off by two).
|
||
//
|
||
|
||
Vcb->ClusterHint =
|
||
(BitIndex = RtlFindClearBits( &Vcb->FreeClusterBitMap, 1, 0 )) != -1 ?
|
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BitIndex + 2 : 2;
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
DebugUnwind( FatSetupAllocationSupport );
|
||
|
||
//
|
||
// If we hit an exception, back out.
|
||
//
|
||
|
||
if (_SEH2_AbnormalTermination()) {
|
||
|
||
FatTearDownAllocationSupport( IrpContext, Vcb );
|
||
}
|
||
} _SEH2_END;
|
||
|
||
return;
|
||
}
|
||
|
||
|
||
VOID
|
||
FatTearDownAllocationSupport (
|
||
IN PIRP_CONTEXT IrpContext,
|
||
IN PVCB Vcb
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine prepares the volume for closing. Specifically, we must
|
||
release the free fat bit map buffer, and uninitialize the dirty fat
|
||
Mcb.
|
||
|
||
Arguments:
|
||
|
||
Vcb - Supplies the Vcb to fill in.
|
||
|
||
Return Value:
|
||
|
||
VOID
|
||
|
||
--*/
|
||
|
||
{
|
||
DebugTrace(+1, Dbg, "FatTearDownAllocationSupport\n", 0);
|
||
DebugTrace( 0, Dbg, " Vcb = %p\n", Vcb);
|
||
|
||
PAGED_CODE();
|
||
|
||
//
|
||
// If there are FAT buckets, free them.
|
||
//
|
||
|
||
if ( Vcb->Windows != NULL ) {
|
||
|
||
ExFreePool( Vcb->Windows );
|
||
Vcb->Windows = NULL;
|
||
}
|
||
|
||
//
|
||
// Free the memory associated with the free cluster bitmap.
|
||
//
|
||
|
||
if ( Vcb->FreeClusterBitMap.Buffer != NULL ) {
|
||
|
||
ExFreePool( Vcb->FreeClusterBitMap.Buffer );
|
||
|
||
//
|
||
// NULL this field as an flag.
|
||
//
|
||
|
||
Vcb->FreeClusterBitMap.Buffer = NULL;
|
||
}
|
||
|
||
//
|
||
// And remove all the runs in the dirty fat Mcb
|
||
//
|
||
|
||
FatRemoveMcbEntry( Vcb, &Vcb->DirtyFatMcb, 0, 0xFFFFFFFF );
|
||
|
||
DebugTrace(-1, Dbg, "FatTearDownAllocationSupport -> (VOID)\n", 0);
|
||
|
||
UNREFERENCED_PARAMETER( IrpContext );
|
||
|
||
return;
|
||
}
|
||
|
||
|
||
_Requires_lock_held_(_Global_critical_region_)
|
||
VOID
|
||
FatLookupFileAllocation (
|
||
IN PIRP_CONTEXT IrpContext,
|
||
IN PFCB FcbOrDcb,
|
||
IN VBO Vbo,
|
||
OUT PLBO Lbo,
|
||
OUT PULONG ByteCount,
|
||
OUT PBOOLEAN Allocated,
|
||
OUT PBOOLEAN EndOnMax,
|
||
OUT PULONG Index
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine looks up the existing mapping of VBO to LBO for a
|
||
file/directory. The information it queries is either stored in the
|
||
mcb field of the fcb/dcb or it is stored on in the fat table and
|
||
needs to be retrieved and decoded, and updated in the mcb.
|
||
|
||
Arguments:
|
||
|
||
FcbOrDcb - Supplies the Fcb/Dcb of the file/directory being queried
|
||
|
||
Vbo - Supplies the VBO whose LBO we want returned
|
||
|
||
Lbo - Receives the LBO corresponding to the input Vbo if one exists
|
||
|
||
ByteCount - Receives the number of bytes within the run the run
|
||
that correpond between the input vbo and output lbo.
|
||
|
||
Allocated - Receives TRUE if the Vbo does have a corresponding Lbo
|
||
and FALSE otherwise.
|
||
|
||
EndOnMax - Receives TRUE if the run ends in the maximal FAT cluster,
|
||
which results in a fractional bytecount.
|
||
|
||
Index - Receives the Index of the run
|
||
|
||
--*/
|
||
|
||
{
|
||
VBO CurrentVbo;
|
||
LBO CurrentLbo;
|
||
LBO PriorLbo;
|
||
|
||
VBO FirstVboOfCurrentRun = 0;
|
||
LBO FirstLboOfCurrentRun;
|
||
|
||
BOOLEAN LastCluster;
|
||
ULONG Runs;
|
||
|
||
PVCB Vcb;
|
||
FAT_ENTRY FatEntry;
|
||
ULONG BytesPerCluster;
|
||
ULARGE_INTEGER BytesOnVolume;
|
||
|
||
FAT_ENUMERATION_CONTEXT Context;
|
||
|
||
PAGED_CODE();
|
||
|
||
Vcb = FcbOrDcb->Vcb;
|
||
|
||
|
||
DebugTrace(+1, Dbg, "FatLookupFileAllocation\n", 0);
|
||
DebugTrace( 0, Dbg, " FcbOrDcb = %p\n", FcbOrDcb);
|
||
DebugTrace( 0, Dbg, " Vbo = %8lx\n", Vbo);
|
||
DebugTrace( 0, Dbg, " pLbo = %8lx\n", Lbo);
|
||
DebugTrace( 0, Dbg, " pByteCount = %8lx\n", ByteCount);
|
||
DebugTrace( 0, Dbg, " pAllocated = %8lx\n", Allocated);
|
||
|
||
Context.Bcb = NULL;
|
||
|
||
*EndOnMax = FALSE;
|
||
|
||
//
|
||
// Check the trivial case that the mapping is already in our
|
||
// Mcb.
|
||
//
|
||
|
||
if ( FatLookupMcbEntry(Vcb, &FcbOrDcb->Mcb, Vbo, Lbo, ByteCount, Index) ) {
|
||
|
||
*Allocated = TRUE;
|
||
|
||
NT_ASSERT( *ByteCount != 0 );
|
||
|
||
//
|
||
// Detect the overflow case, trim and claim the condition.
|
||
//
|
||
|
||
if (Vbo + *ByteCount == 0) {
|
||
|
||
*EndOnMax = TRUE;
|
||
}
|
||
|
||
DebugTrace( 0, Dbg, "Found run in Mcb.\n", 0);
|
||
DebugTrace(-1, Dbg, "FatLookupFileAllocation -> (VOID)\n", 0);
|
||
return;
|
||
}
|
||
|
||
//
|
||
// Initialize the Vcb, the cluster size, LastCluster, and
|
||
// FirstLboOfCurrentRun (to be used as an indication of the first
|
||
// iteration through the following while loop).
|
||
//
|
||
|
||
BytesPerCluster = 1 << Vcb->AllocationSupport.LogOfBytesPerCluster;
|
||
|
||
BytesOnVolume.QuadPart = UInt32x32To64( Vcb->AllocationSupport.NumberOfClusters, BytesPerCluster );
|
||
|
||
LastCluster = FALSE;
|
||
FirstLboOfCurrentRun = 0;
|
||
|
||
//
|
||
// Discard the case that the request extends beyond the end of
|
||
// allocation. Note that if the allocation size if not known
|
||
// AllocationSize is set to 0xffffffff.
|
||
//
|
||
|
||
if ( Vbo >= FcbOrDcb->Header.AllocationSize.LowPart ) {
|
||
|
||
*Allocated = FALSE;
|
||
|
||
DebugTrace( 0, Dbg, "Vbo beyond end of file.\n", 0);
|
||
DebugTrace(-1, Dbg, "FatLookupFileAllocation -> (VOID)\n", 0);
|
||
return;
|
||
}
|
||
|
||
//
|
||
// The Vbo is beyond the last Mcb entry. So we adjust Current Vbo/Lbo
|
||
// and FatEntry to describe the beginning of the last entry in the Mcb.
|
||
// This is used as initialization for the following loop.
|
||
//
|
||
// If the Mcb was empty, we start at the beginning of the file with
|
||
// CurrentVbo set to 0 to indicate a new run.
|
||
//
|
||
|
||
if (FatLookupLastMcbEntry( Vcb, &FcbOrDcb->Mcb, &CurrentVbo, &CurrentLbo, &Runs )) {
|
||
|
||
DebugTrace( 0, Dbg, "Current Mcb size = %8lx.\n", CurrentVbo + 1);
|
||
|
||
CurrentVbo -= (BytesPerCluster - 1);
|
||
CurrentLbo -= (BytesPerCluster - 1);
|
||
|
||
//
|
||
// Convert an index to a count.
|
||
//
|
||
|
||
Runs += 1;
|
||
|
||
} else {
|
||
|
||
DebugTrace( 0, Dbg, "Mcb empty.\n", 0);
|
||
|
||
//
|
||
// Check for an FcbOrDcb that has no allocation
|
||
//
|
||
|
||
if (FcbOrDcb->FirstClusterOfFile == 0) {
|
||
|
||
*Allocated = FALSE;
|
||
|
||
DebugTrace( 0, Dbg, "File has no allocation.\n", 0);
|
||
DebugTrace(-1, Dbg, "FatLookupFileAllocation -> (VOID)\n", 0);
|
||
return;
|
||
|
||
} else {
|
||
|
||
CurrentVbo = 0;
|
||
CurrentLbo = FatGetLboFromIndex( Vcb, FcbOrDcb->FirstClusterOfFile );
|
||
FirstVboOfCurrentRun = CurrentVbo;
|
||
FirstLboOfCurrentRun = CurrentLbo;
|
||
|
||
Runs = 0;
|
||
|
||
DebugTrace( 0, Dbg, "First Lbo of file = %8lx\n", CurrentLbo);
|
||
}
|
||
}
|
||
|
||
//
|
||
// Now we know that we are looking up a valid Vbo, but it is
|
||
// not in the Mcb, which is a monotonically increasing list of
|
||
// Vbo's. Thus we have to go to the Fat, and update
|
||
// the Mcb as we go. We use a try-finally to unpin the page
|
||
// of fat hanging around. Also we mark *Allocated = FALSE, so that
|
||
// the caller wont try to use the data if we hit an exception.
|
||
//
|
||
|
||
*Allocated = FALSE;
|
||
|
||
_SEH2_TRY {
|
||
|
||
FatEntry = (FAT_ENTRY)FatGetIndexFromLbo( Vcb, CurrentLbo );
|
||
|
||
//
|
||
// ASSERT that CurrentVbo and CurrentLbo are now cluster alligned.
|
||
// The assumption here, is that only whole clusters of Vbos and Lbos
|
||
// are mapped in the Mcb.
|
||
//
|
||
|
||
NT_ASSERT( ((CurrentLbo - Vcb->AllocationSupport.FileAreaLbo)
|
||
% BytesPerCluster == 0) &&
|
||
(CurrentVbo % BytesPerCluster == 0) );
|
||
|
||
//
|
||
// Starting from the first Vbo after the last Mcb entry, scan through
|
||
// the Fat looking for our Vbo. We continue through the Fat until we
|
||
// hit a noncontiguity beyond the desired Vbo, or the last cluster.
|
||
//
|
||
|
||
while ( !LastCluster ) {
|
||
|
||
//
|
||
// Get the next fat entry, and update our Current variables.
|
||
//
|
||
|
||
FatLookupFatEntry( IrpContext, Vcb, FatEntry, (PULONG)&FatEntry, &Context );
|
||
|
||
PriorLbo = CurrentLbo;
|
||
CurrentLbo = FatGetLboFromIndex( Vcb, FatEntry );
|
||
CurrentVbo += BytesPerCluster;
|
||
|
||
switch ( FatInterpretClusterType( Vcb, FatEntry )) {
|
||
|
||
//
|
||
// Check for a break in the Fat allocation chain.
|
||
//
|
||
|
||
case FatClusterAvailable:
|
||
case FatClusterReserved:
|
||
case FatClusterBad:
|
||
|
||
DebugTrace( 0, Dbg, "Break in allocation chain, entry = %d\n", FatEntry);
|
||
DebugTrace(-1, Dbg, "FatLookupFileAllocation -> Fat Corrupt. Raise Status.\n", 0);
|
||
|
||
FatPopUpFileCorrupt( IrpContext, FcbOrDcb );
|
||
FatRaiseStatus( IrpContext, STATUS_FILE_CORRUPT_ERROR );
|
||
break;
|
||
|
||
//
|
||
// If this is the last cluster, we must update the Mcb and
|
||
// exit the loop.
|
||
//
|
||
|
||
case FatClusterLast:
|
||
|
||
//
|
||
// Assert we know where the current run started. If the
|
||
// Mcb was empty when we were called, thenFirstLboOfCurrentRun
|
||
// was set to the start of the file. If the Mcb contained an
|
||
// entry, then FirstLboOfCurrentRun was set on the first
|
||
// iteration through the loop. Thus if FirstLboOfCurrentRun
|
||
// is 0, then there was an Mcb entry and we are on our first
|
||
// iteration, meaing that the last cluster in the Mcb was
|
||
// really the last allocated cluster, but we checked Vbo
|
||
// against AllocationSize, and found it OK, thus AllocationSize
|
||
// must be too large.
|
||
//
|
||
// Note that, when we finally arrive here, CurrentVbo is actually
|
||
// the first Vbo beyond the file allocation and CurrentLbo is
|
||
// meaningless.
|
||
//
|
||
|
||
DebugTrace( 0, Dbg, "Read last cluster of file.\n", 0);
|
||
|
||
//
|
||
// Detect the case of the maximal file. Note that this really isn't
|
||
// a proper Vbo - those are zero-based, and this is a one-based number.
|
||
// The maximal file, of 2^32 - 1 bytes, has a maximum byte offset of
|
||
// 2^32 - 2.
|
||
//
|
||
// Just so we don't get confused here.
|
||
//
|
||
|
||
if (CurrentVbo == 0) {
|
||
|
||
*EndOnMax = TRUE;
|
||
CurrentVbo -= 1;
|
||
}
|
||
|
||
LastCluster = TRUE;
|
||
|
||
if (FirstLboOfCurrentRun != 0 ) {
|
||
|
||
DebugTrace( 0, Dbg, "Adding a run to the Mcb.\n", 0);
|
||
DebugTrace( 0, Dbg, " Vbo = %08lx.\n", FirstVboOfCurrentRun);
|
||
DebugTrace( 0, Dbg, " Lbo = %08lx.\n", FirstLboOfCurrentRun);
|
||
DebugTrace( 0, Dbg, " Length = %08lx.\n", CurrentVbo - FirstVboOfCurrentRun);
|
||
|
||
(VOID)FatAddMcbEntry( Vcb,
|
||
&FcbOrDcb->Mcb,
|
||
FirstVboOfCurrentRun,
|
||
FirstLboOfCurrentRun,
|
||
CurrentVbo - FirstVboOfCurrentRun );
|
||
|
||
Runs += 1;
|
||
}
|
||
|
||
//
|
||
// Being at the end of allocation, make sure we have found
|
||
// the Vbo. If we haven't, seeing as we checked VBO
|
||
// against AllocationSize, the real disk allocation is less
|
||
// than that of AllocationSize. This comes about when the
|
||
// real allocation is not yet known, and AllocaitonSize
|
||
// contains MAXULONG.
|
||
//
|
||
// KLUDGE! - If we were called by FatLookupFileAllocationSize
|
||
// Vbo is set to MAXULONG - 1, and AllocationSize to the lookup
|
||
// hint. Thus we merrily go along looking for a match that isn't
|
||
// there, but in the meantime building an Mcb. If this is
|
||
// the case, fill in AllocationSize and return.
|
||
//
|
||
|
||
if ( Vbo == MAXULONG - 1 ) {
|
||
|
||
*Allocated = FALSE;
|
||
|
||
FcbOrDcb->Header.AllocationSize.QuadPart = CurrentVbo;
|
||
|
||
DebugTrace( 0, Dbg, "New file allocation size = %08lx.\n", CurrentVbo);
|
||
try_return ( NOTHING );
|
||
}
|
||
|
||
//
|
||
// We will lie ever so slightly if we really terminated on the
|
||
// maximal byte of a file. It is really allocated.
|
||
//
|
||
|
||
if (Vbo >= CurrentVbo && !*EndOnMax) {
|
||
|
||
*Allocated = FALSE;
|
||
try_return ( NOTHING );
|
||
}
|
||
|
||
break;
|
||
|
||
//
|
||
// This is a continuation in the chain. If the run has a
|
||
// discontiguity at this point, update the Mcb, and if we are beyond
|
||
// the desired Vbo, this is the end of the run, so set LastCluster
|
||
// and exit the loop.
|
||
//
|
||
|
||
case FatClusterNext:
|
||
|
||
//
|
||
// This is the loop check. The Vbo must not be bigger than the size of
|
||
// the volume, and the Vbo must not have a) wrapped and b) not been at the
|
||
// very last cluster in the chain, for the case of the maximal file.
|
||
//
|
||
|
||
if ( CurrentVbo == 0 ||
|
||
(BytesOnVolume.HighPart == 0 && CurrentVbo > BytesOnVolume.LowPart)) {
|
||
|
||
FatPopUpFileCorrupt( IrpContext, FcbOrDcb );
|
||
FatRaiseStatus( IrpContext, STATUS_FILE_CORRUPT_ERROR );
|
||
}
|
||
|
||
if ( PriorLbo + BytesPerCluster != CurrentLbo ) {
|
||
|
||
//
|
||
// Note that on the first time through the loop
|
||
// (FirstLboOfCurrentRun == 0), we don't add the
|
||
// run to the Mcb since it curresponds to the last
|
||
// run already stored in the Mcb.
|
||
//
|
||
|
||
if ( FirstLboOfCurrentRun != 0 ) {
|
||
|
||
DebugTrace( 0, Dbg, "Adding a run to the Mcb.\n", 0);
|
||
DebugTrace( 0, Dbg, " Vbo = %08lx.\n", FirstVboOfCurrentRun);
|
||
DebugTrace( 0, Dbg, " Lbo = %08lx.\n", FirstLboOfCurrentRun);
|
||
DebugTrace( 0, Dbg, " Length = %08lx.\n", CurrentVbo - FirstVboOfCurrentRun);
|
||
|
||
FatAddMcbEntry( Vcb,
|
||
&FcbOrDcb->Mcb,
|
||
FirstVboOfCurrentRun,
|
||
FirstLboOfCurrentRun,
|
||
CurrentVbo - FirstVboOfCurrentRun );
|
||
|
||
Runs += 1;
|
||
}
|
||
|
||
//
|
||
// Since we are at a run boundry, with CurrentLbo and
|
||
// CurrentVbo being the first cluster of the next run,
|
||
// we see if the run we just added encompases the desired
|
||
// Vbo, and if so exit. Otherwise we set up two new
|
||
// First*boOfCurrentRun, and continue.
|
||
//
|
||
|
||
if (CurrentVbo > Vbo) {
|
||
|
||
LastCluster = TRUE;
|
||
|
||
} else {
|
||
|
||
FirstVboOfCurrentRun = CurrentVbo;
|
||
FirstLboOfCurrentRun = CurrentLbo;
|
||
}
|
||
}
|
||
break;
|
||
|
||
default:
|
||
|
||
DebugTrace(0, Dbg, "Illegal Cluster Type.\n", FatEntry);
|
||
|
||
#ifdef _MSC_VER
|
||
#pragma prefast( suppress: 28159, "we bugcheck here because our internal data structures are seriously corrupted if this happens" )
|
||
#endif
|
||
FatBugCheck( 0, 0, 0 );
|
||
|
||
break;
|
||
|
||
} // switch()
|
||
} // while()
|
||
|
||
//
|
||
// Load up the return parameters.
|
||
//
|
||
// On exit from the loop, Vbo still contains the desired Vbo, and
|
||
// CurrentVbo is the first byte after the run that contained the
|
||
// desired Vbo.
|
||
//
|
||
|
||
*Allocated = TRUE;
|
||
|
||
*Lbo = FirstLboOfCurrentRun + (Vbo - FirstVboOfCurrentRun);
|
||
|
||
*ByteCount = CurrentVbo - Vbo;
|
||
|
||
if (ARGUMENT_PRESENT(Index)) {
|
||
|
||
//
|
||
// Note that Runs only needs to be accurate with respect to where we
|
||
// ended. Since partial-lookup cases will occur without exclusive
|
||
// synchronization, the Mcb itself may be much bigger by now.
|
||
//
|
||
|
||
*Index = Runs - 1;
|
||
}
|
||
|
||
try_exit: NOTHING;
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
DebugUnwind( FatLookupFileAllocation );
|
||
|
||
//
|
||
// We are done reading the Fat, so unpin the last page of fat
|
||
// that is hanging around
|
||
//
|
||
|
||
FatUnpinBcb( IrpContext, Context.Bcb );
|
||
|
||
DebugTrace(-1, Dbg, "FatLookupFileAllocation -> (VOID)\n", 0);
|
||
} _SEH2_END;
|
||
|
||
return;
|
||
}
|
||
|
||
|
||
_Requires_lock_held_(_Global_critical_region_)
|
||
VOID
|
||
FatAddFileAllocation (
|
||
IN PIRP_CONTEXT IrpContext,
|
||
IN PFCB FcbOrDcb,
|
||
IN PFILE_OBJECT FileObject OPTIONAL,
|
||
IN ULONG DesiredAllocationSize
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine adds additional allocation to the specified file/directory.
|
||
Additional allocation is added by appending clusters to the file/directory.
|
||
|
||
If the file already has a sufficient allocation then this procedure
|
||
is effectively a noop.
|
||
|
||
Arguments:
|
||
|
||
FcbOrDcb - Supplies the Fcb/Dcb of the file/directory being modified.
|
||
This parameter must not specify the root dcb.
|
||
|
||
FileObject - If supplied inform the cache manager of the change.
|
||
|
||
DesiredAllocationSize - Supplies the minimum size, in bytes, that we want
|
||
allocated to the file/directory.
|
||
|
||
--*/
|
||
|
||
{
|
||
PVCB Vcb;
|
||
LARGE_MCB NewMcb = {0};
|
||
PLARGE_MCB McbToCleanup = NULL;
|
||
PDIRENT Dirent = NULL;
|
||
ULONG NewAllocation = 0;
|
||
PBCB Bcb = NULL;
|
||
BOOLEAN UnwindWeAllocatedDiskSpace = FALSE;
|
||
BOOLEAN UnwindAllocationSizeSet = FALSE;
|
||
BOOLEAN UnwindCacheManagerInformed = FALSE;
|
||
BOOLEAN UnwindWeInitializedMcb = FALSE;
|
||
|
||
PAGED_CODE();
|
||
|
||
DebugTrace(+1, Dbg, "FatAddFileAllocation\n", 0);
|
||
DebugTrace( 0, Dbg, " FcbOrDcb = %p\n", FcbOrDcb);
|
||
DebugTrace( 0, Dbg, " DesiredAllocationSize = %8lx\n", DesiredAllocationSize);
|
||
|
||
Vcb = FcbOrDcb->Vcb;
|
||
|
||
//
|
||
// If we haven't yet set the correct AllocationSize, do so.
|
||
//
|
||
|
||
if (FcbOrDcb->Header.AllocationSize.QuadPart == FCB_LOOKUP_ALLOCATIONSIZE_HINT) {
|
||
|
||
FatLookupFileAllocationSize( IrpContext, FcbOrDcb );
|
||
}
|
||
|
||
//
|
||
// Check for the benign case that the desired allocation is already
|
||
// within the allocation size.
|
||
//
|
||
|
||
if (DesiredAllocationSize <= FcbOrDcb->Header.AllocationSize.LowPart) {
|
||
|
||
DebugTrace(0, Dbg, "Desired size within current allocation.\n", 0);
|
||
|
||
DebugTrace(-1, Dbg, "FatAddFileAllocation -> (VOID)\n", 0);
|
||
return;
|
||
}
|
||
|
||
DebugTrace( 0, Dbg, "InitialAllocation = %08lx.\n", FcbOrDcb->Header.AllocationSize.LowPart);
|
||
|
||
//
|
||
// Get a chunk of disk space that will fullfill our needs. If there
|
||
// was no initial allocation, start from the hint in the Vcb, otherwise
|
||
// try to allocate from the cluster after the initial allocation.
|
||
//
|
||
// If there was no initial allocation to the file, we can just use the
|
||
// Mcb in the FcbOrDcb, otherwise we have to use a new one, and merge
|
||
// it to the one in the FcbOrDcb.
|
||
//
|
||
|
||
_SEH2_TRY {
|
||
|
||
if (FcbOrDcb->Header.AllocationSize.LowPart == 0) {
|
||
|
||
LBO FirstLboOfFile;
|
||
|
||
NT_ASSERT( FcbOrDcb->FcbCondition == FcbGood );
|
||
|
||
FatGetDirentFromFcbOrDcb( IrpContext,
|
||
FcbOrDcb,
|
||
FALSE,
|
||
&Dirent,
|
||
&Bcb );
|
||
//
|
||
// Set this dirty right now since this call can fail.
|
||
//
|
||
|
||
FatSetDirtyBcb( IrpContext, Bcb, Vcb, TRUE );
|
||
|
||
FatAllocateDiskSpace( IrpContext,
|
||
Vcb,
|
||
0,
|
||
&DesiredAllocationSize,
|
||
FALSE,
|
||
&FcbOrDcb->Mcb );
|
||
|
||
UnwindWeAllocatedDiskSpace = TRUE;
|
||
McbToCleanup = &FcbOrDcb->Mcb;
|
||
|
||
//
|
||
// We have to update the dirent and FcbOrDcb copies of
|
||
// FirstClusterOfFile since before it was 0
|
||
//
|
||
|
||
FatLookupMcbEntry( FcbOrDcb->Vcb,
|
||
&FcbOrDcb->Mcb,
|
||
0,
|
||
&FirstLboOfFile,
|
||
(PULONG)NULL,
|
||
NULL );
|
||
|
||
DebugTrace( 0, Dbg, "First Lbo of file will be %08lx.\n", FirstLboOfFile );
|
||
|
||
FcbOrDcb->FirstClusterOfFile = FatGetIndexFromLbo( Vcb, FirstLboOfFile );
|
||
|
||
Dirent->FirstClusterOfFile = (USHORT)FcbOrDcb->FirstClusterOfFile;
|
||
|
||
if ( FatIsFat32(Vcb) ) {
|
||
|
||
Dirent->FirstClusterOfFileHi = (USHORT)(FcbOrDcb->FirstClusterOfFile >> 16);
|
||
}
|
||
|
||
//
|
||
// Note the size of the allocation we need to tell the cache manager about.
|
||
//
|
||
|
||
NewAllocation = DesiredAllocationSize;
|
||
|
||
} else {
|
||
|
||
LBO LastAllocatedLbo;
|
||
VBO DontCare;
|
||
|
||
//
|
||
// Get the first cluster following the current allocation. It is possible
|
||
// the Mcb is empty (or short, etc.) so we need to be slightly careful
|
||
// about making sure we don't lie with the hint.
|
||
//
|
||
|
||
(void)FatLookupLastMcbEntry( FcbOrDcb->Vcb, &FcbOrDcb->Mcb, &DontCare, &LastAllocatedLbo, NULL );
|
||
|
||
//
|
||
// Try to get some disk space starting from there.
|
||
//
|
||
|
||
NewAllocation = DesiredAllocationSize - FcbOrDcb->Header.AllocationSize.LowPart;
|
||
|
||
FsRtlInitializeLargeMcb( &NewMcb, PagedPool );
|
||
UnwindWeInitializedMcb = TRUE;
|
||
McbToCleanup = &NewMcb;
|
||
|
||
FatAllocateDiskSpace( IrpContext,
|
||
Vcb,
|
||
(LastAllocatedLbo != ~0 ?
|
||
FatGetIndexFromLbo(Vcb,LastAllocatedLbo + 1) :
|
||
0),
|
||
&NewAllocation,
|
||
FALSE,
|
||
&NewMcb );
|
||
|
||
UnwindWeAllocatedDiskSpace = TRUE;
|
||
}
|
||
|
||
//
|
||
// Now that we increased the allocation of the file, mark it in the
|
||
// FcbOrDcb. Carefully prepare to handle an inability to grow the cache
|
||
// structures.
|
||
//
|
||
|
||
FcbOrDcb->Header.AllocationSize.LowPart += NewAllocation;
|
||
|
||
//
|
||
// Handle the maximal file case, where we may have just wrapped. Note
|
||
// that this must be the precise boundary case wrap, i.e. by one byte,
|
||
// so that the new allocation is actually one byte "less" as far as we're
|
||
// concerned. This is important for the extension case.
|
||
//
|
||
|
||
if (FcbOrDcb->Header.AllocationSize.LowPart == 0) {
|
||
|
||
NewAllocation -= 1;
|
||
FcbOrDcb->Header.AllocationSize.LowPart = 0xffffffff;
|
||
}
|
||
|
||
UnwindAllocationSizeSet = TRUE;
|
||
|
||
//
|
||
// Inform the cache manager to increase the section size
|
||
//
|
||
|
||
if ( ARGUMENT_PRESENT(FileObject) && CcIsFileCached(FileObject) ) {
|
||
|
||
CcSetFileSizes( FileObject,
|
||
(PCC_FILE_SIZES)&FcbOrDcb->Header.AllocationSize );
|
||
UnwindCacheManagerInformed = TRUE;
|
||
}
|
||
|
||
//
|
||
// In the extension case, we have held off actually gluing the new
|
||
// allocation onto the file. This simplifies exception cleanup since
|
||
// if it was already added and the section grow failed, we'd have to
|
||
// do extra work to unglue it. This way, we can assume that if we
|
||
// raise the only thing we need to do is deallocate the disk space.
|
||
//
|
||
// Merge the allocation now.
|
||
//
|
||
|
||
if (FcbOrDcb->Header.AllocationSize.LowPart != NewAllocation) {
|
||
|
||
//
|
||
// Tack the new Mcb onto the end of the FcbOrDcb one.
|
||
//
|
||
|
||
FatMergeAllocation( IrpContext,
|
||
Vcb,
|
||
&FcbOrDcb->Mcb,
|
||
&NewMcb );
|
||
}
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
DebugUnwind( FatAddFileAllocation );
|
||
|
||
//
|
||
// Give FlushFileBuffer/Cleanup a clue here, regardless of success/fail..
|
||
//
|
||
|
||
SetFlag(FcbOrDcb->FcbState, FCB_STATE_FLUSH_FAT);
|
||
|
||
//
|
||
// If we were dogged trying to complete this operation, we need to go
|
||
// back various things out.
|
||
//
|
||
|
||
if (_SEH2_AbnormalTermination()) {
|
||
|
||
//
|
||
// Pull off the allocation size we tried to add to this object if
|
||
// we failed to grow cache structures or Mcb structures.
|
||
//
|
||
|
||
if (UnwindAllocationSizeSet) {
|
||
|
||
FcbOrDcb->Header.AllocationSize.LowPart -= NewAllocation;
|
||
}
|
||
|
||
if (UnwindCacheManagerInformed) {
|
||
|
||
CcSetFileSizes( FileObject,
|
||
(PCC_FILE_SIZES)&FcbOrDcb->Header.AllocationSize );
|
||
}
|
||
|
||
//
|
||
// In the case of initial allocation, we used the Fcb's Mcb and have
|
||
// to clean that up as well as the FAT chain references.
|
||
//
|
||
|
||
if (FcbOrDcb->Header.AllocationSize.LowPart == 0) {
|
||
|
||
if (Dirent != NULL) {
|
||
|
||
FcbOrDcb->FirstClusterOfFile = 0;
|
||
Dirent->FirstClusterOfFile = 0;
|
||
|
||
if ( FatIsFat32(Vcb) ) {
|
||
|
||
Dirent->FirstClusterOfFileHi = 0;
|
||
}
|
||
}
|
||
}
|
||
|
||
//
|
||
// ... and drop the dirent Bcb if we got it. Do it now
|
||
// so we can afford to take the exception if we have to.
|
||
//
|
||
|
||
FatUnpinBcb( IrpContext, Bcb );
|
||
|
||
_SEH2_TRY {
|
||
|
||
//
|
||
// Note this can re-raise.
|
||
//
|
||
|
||
if ( UnwindWeAllocatedDiskSpace ) {
|
||
|
||
FatDeallocateDiskSpace( IrpContext, Vcb, McbToCleanup, FALSE );
|
||
}
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
//
|
||
// We always want to clean up the non-initial allocation temporary Mcb,
|
||
// otherwise we have the Fcb's Mcb and we just truncate it away.
|
||
//
|
||
|
||
if (UnwindWeInitializedMcb == TRUE) {
|
||
|
||
//
|
||
// Note that we already know a raise is in progress. No danger
|
||
// of encountering the normal case code below and doing this again.
|
||
//
|
||
|
||
FsRtlUninitializeLargeMcb( McbToCleanup );
|
||
|
||
} else {
|
||
|
||
if (McbToCleanup) {
|
||
|
||
FsRtlTruncateLargeMcb( McbToCleanup, 0 );
|
||
}
|
||
}
|
||
} _SEH2_END;
|
||
}
|
||
|
||
DebugTrace(-1, Dbg, "FatAddFileAllocation -> (VOID)\n", 0);
|
||
} _SEH2_END;
|
||
|
||
//
|
||
// Non-exceptional cleanup we always want to do. In handling the re-raise possibilities
|
||
// during exceptions we had to make sure these two steps always happened there beforehand.
|
||
// So now we handle the usual case.
|
||
//
|
||
|
||
FatUnpinBcb( IrpContext, Bcb );
|
||
|
||
if (UnwindWeInitializedMcb == TRUE) {
|
||
|
||
FsRtlUninitializeLargeMcb( &NewMcb );
|
||
}
|
||
}
|
||
|
||
_Requires_lock_held_(_Global_critical_region_)
|
||
VOID
|
||
FatTruncateFileAllocation (
|
||
IN PIRP_CONTEXT IrpContext,
|
||
IN PFCB FcbOrDcb,
|
||
IN ULONG DesiredAllocationSize
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine truncates the allocation to the specified file/directory.
|
||
|
||
If the file is already smaller than the indicated size then this procedure
|
||
is effectively a noop.
|
||
|
||
|
||
Arguments:
|
||
|
||
FcbOrDcb - Supplies the Fcb/Dcb of the file/directory being modified
|
||
This parameter must not specify the root dcb.
|
||
|
||
DesiredAllocationSize - Supplies the maximum size, in bytes, that we want
|
||
allocated to the file/directory. It is rounded
|
||
up to the nearest cluster.
|
||
|
||
Return Value:
|
||
|
||
VOID - TRUE if the operation completed and FALSE if it had to
|
||
block but could not.
|
||
|
||
--*/
|
||
|
||
{
|
||
PVCB Vcb;
|
||
PBCB Bcb = NULL;
|
||
LARGE_MCB RemainingMcb = {0};
|
||
ULONG BytesPerCluster;
|
||
PDIRENT Dirent = NULL;
|
||
BOOLEAN UpdatedDirent = FALSE;
|
||
|
||
ULONG UnwindInitialAllocationSize;
|
||
ULONG UnwindInitialFirstClusterOfFile;
|
||
BOOLEAN UnwindWeAllocatedMcb = FALSE;
|
||
|
||
PAGED_CODE();
|
||
|
||
Vcb = FcbOrDcb->Vcb;
|
||
|
||
DebugTrace(+1, Dbg, "FatTruncateFileAllocation\n", 0);
|
||
DebugTrace( 0, Dbg, " FcbOrDcb = %p\n", FcbOrDcb);
|
||
DebugTrace( 0, Dbg, " DesiredAllocationSize = %8lx\n", DesiredAllocationSize);
|
||
|
||
//
|
||
// If the Fcb isn't in good condition, we have no business whacking around on
|
||
// the disk after "its" clusters.
|
||
//
|
||
// Inspired by a Prefix complaint.
|
||
//
|
||
|
||
NT_ASSERT( FcbOrDcb->FcbCondition == FcbGood );
|
||
|
||
//
|
||
// If we haven't yet set the correct AllocationSize, do so.
|
||
//
|
||
|
||
if (FcbOrDcb->Header.AllocationSize.QuadPart == FCB_LOOKUP_ALLOCATIONSIZE_HINT) {
|
||
|
||
FatLookupFileAllocationSize( IrpContext, FcbOrDcb );
|
||
}
|
||
|
||
//
|
||
// Round up the Desired Allocation Size to the next cluster size
|
||
//
|
||
|
||
BytesPerCluster = 1 << Vcb->AllocationSupport.LogOfBytesPerCluster;
|
||
|
||
//
|
||
// Note if the desired allocation is zero, to distinguish this from
|
||
// the wrap case below.
|
||
//
|
||
|
||
if (DesiredAllocationSize != 0) {
|
||
|
||
DesiredAllocationSize = (DesiredAllocationSize + (BytesPerCluster - 1)) &
|
||
~(BytesPerCluster - 1);
|
||
//
|
||
// Check for the benign case that the file is already smaller than
|
||
// the desired truncation. Note that if it wraps, then a) it was
|
||
// specifying an offset in the maximally allocatable cluster and
|
||
// b) we're not asking to extend the file, either. So stop.
|
||
//
|
||
|
||
if (DesiredAllocationSize == 0 ||
|
||
DesiredAllocationSize >= FcbOrDcb->Header.AllocationSize.LowPart) {
|
||
|
||
DebugTrace(0, Dbg, "Desired size within current allocation.\n", 0);
|
||
|
||
DebugTrace(-1, Dbg, "FatTruncateFileAllocation -> (VOID)\n", 0);
|
||
return;
|
||
}
|
||
|
||
}
|
||
|
||
//
|
||
// This is a no-op if the allocation size is already what we want.
|
||
//
|
||
|
||
if (DesiredAllocationSize == FcbOrDcb->Header.AllocationSize.LowPart) {
|
||
|
||
DebugTrace(0, Dbg, "Desired size equals current allocation.\n", 0);
|
||
DebugTrace(-1, Dbg, "FatTruncateFileAllocation -> (VOID)\n", 0);
|
||
return;
|
||
}
|
||
|
||
UnwindInitialAllocationSize = FcbOrDcb->Header.AllocationSize.LowPart;
|
||
UnwindInitialFirstClusterOfFile = FcbOrDcb->FirstClusterOfFile;
|
||
|
||
//
|
||
// Update the FcbOrDcb allocation size. If it is now zero, we have the
|
||
// additional task of modifying the FcbOrDcb and Dirent copies of
|
||
// FirstClusterInFile.
|
||
//
|
||
// Note that we must pin the dirent before actually deallocating the
|
||
// disk space since, in unwind, it would not be possible to reallocate
|
||
// deallocated disk space as someone else may have reallocated it and
|
||
// may cause an exception when you try to get some more disk space.
|
||
// Thus FatDeallocateDiskSpace must be the final dangerous operation.
|
||
//
|
||
|
||
_SEH2_TRY {
|
||
|
||
FcbOrDcb->Header.AllocationSize.QuadPart = DesiredAllocationSize;
|
||
|
||
//
|
||
// Special case 0
|
||
//
|
||
|
||
if (DesiredAllocationSize == 0) {
|
||
|
||
//
|
||
// We have to update the dirent and FcbOrDcb copies of
|
||
// FirstClusterOfFile since before it was 0
|
||
//
|
||
|
||
NT_ASSERT( FcbOrDcb->FcbCondition == FcbGood );
|
||
|
||
FatGetDirentFromFcbOrDcb( IrpContext, FcbOrDcb, FALSE, &Dirent, &Bcb );
|
||
|
||
Dirent->FirstClusterOfFile = 0;
|
||
|
||
if (FatIsFat32(Vcb)) {
|
||
|
||
Dirent->FirstClusterOfFileHi = 0;
|
||
}
|
||
|
||
FcbOrDcb->FirstClusterOfFile = 0;
|
||
|
||
FatSetDirtyBcb( IrpContext, Bcb, Vcb, TRUE );
|
||
UpdatedDirent = TRUE;
|
||
|
||
FatDeallocateDiskSpace( IrpContext, Vcb, &FcbOrDcb->Mcb, ((FcbOrDcb->FcbState & FCB_STATE_ZERO_ON_DEALLOCATION) != 0));
|
||
|
||
FatRemoveMcbEntry( FcbOrDcb->Vcb, &FcbOrDcb->Mcb, 0, 0xFFFFFFFF );
|
||
|
||
} else {
|
||
|
||
//
|
||
// Split the existing allocation into two parts, one we will keep, and
|
||
// one we will deallocate.
|
||
//
|
||
|
||
FsRtlInitializeLargeMcb( &RemainingMcb, PagedPool );
|
||
UnwindWeAllocatedMcb = TRUE;
|
||
|
||
FatSplitAllocation( IrpContext,
|
||
Vcb,
|
||
&FcbOrDcb->Mcb,
|
||
DesiredAllocationSize,
|
||
&RemainingMcb );
|
||
|
||
FatDeallocateDiskSpace( IrpContext, Vcb, &RemainingMcb, ((FcbOrDcb->FcbState & FCB_STATE_ZERO_ON_DEALLOCATION) != 0) );
|
||
|
||
FsRtlUninitializeLargeMcb( &RemainingMcb );
|
||
}
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
DebugUnwind( FatTruncateFileAllocation );
|
||
|
||
//
|
||
// Is this really the right backout strategy? It would be nice if we could
|
||
// pretend the truncate worked if we knew that the file had gotten into
|
||
// a consistent state. Leaving dangled clusters is probably quite preferable.
|
||
//
|
||
|
||
if ( _SEH2_AbnormalTermination() ) {
|
||
|
||
FcbOrDcb->Header.AllocationSize.LowPart = UnwindInitialAllocationSize;
|
||
|
||
if ( (DesiredAllocationSize == 0) && (Dirent != NULL)) {
|
||
|
||
if (UpdatedDirent) {
|
||
|
||
//
|
||
// If the dirent has been updated ok and marked dirty, then we
|
||
// failed in deallocatediscspace, and don't know what state
|
||
// the on disc fat chain is in. So we throw away the mcb,
|
||
// and potentially loose a few clusters until the next
|
||
// chkdsk. The operation has succeeded, but the exception
|
||
// will still propogate. 5.1
|
||
//
|
||
|
||
FatRemoveMcbEntry( Vcb, &FcbOrDcb->Mcb, 0, 0xFFFFFFFF );
|
||
FcbOrDcb->Header.AllocationSize.QuadPart = 0;
|
||
}
|
||
else if (FcbOrDcb->FirstClusterOfFile == 0) {
|
||
|
||
Dirent->FirstClusterOfFile = (USHORT)UnwindInitialFirstClusterOfFile;
|
||
|
||
if ( FatIsFat32(Vcb) ) {
|
||
|
||
Dirent->FirstClusterOfFileHi =
|
||
(USHORT)(UnwindInitialFirstClusterOfFile >> 16);
|
||
}
|
||
|
||
FcbOrDcb->FirstClusterOfFile = UnwindInitialFirstClusterOfFile;
|
||
}
|
||
}
|
||
|
||
if ( UnwindWeAllocatedMcb ) {
|
||
|
||
FsRtlUninitializeLargeMcb( &RemainingMcb );
|
||
}
|
||
|
||
//
|
||
// Note that in the non zero truncation case, we will also
|
||
// leak clusters. However, apart from this, the in memory and on disc
|
||
// structures will agree.
|
||
}
|
||
|
||
FatUnpinBcb( IrpContext, Bcb );
|
||
|
||
//
|
||
// Give FlushFileBuffer/Cleanup a clue here, regardless of success/fail.
|
||
//
|
||
|
||
SetFlag(FcbOrDcb->FcbState, FCB_STATE_FLUSH_FAT);
|
||
|
||
DebugTrace(-1, Dbg, "FatTruncateFileAllocation -> (VOID)\n", 0);
|
||
} _SEH2_END;
|
||
}
|
||
|
||
|
||
_Requires_lock_held_(_Global_critical_region_)
|
||
VOID
|
||
FatLookupFileAllocationSize (
|
||
IN PIRP_CONTEXT IrpContext,
|
||
IN PFCB FcbOrDcb
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine retrieves the current file allocatio size for the
|
||
specified file/directory.
|
||
|
||
Arguments:
|
||
|
||
FcbOrDcb - Supplies the Fcb/Dcb of the file/directory being modified
|
||
|
||
--*/
|
||
|
||
{
|
||
LBO Lbo;
|
||
ULONG ByteCount;
|
||
BOOLEAN DontCare;
|
||
|
||
PAGED_CODE();
|
||
|
||
DebugTrace(+1, Dbg, "FatLookupAllocationSize\n", 0);
|
||
DebugTrace( 0, Dbg, " FcbOrDcb = %p\n", FcbOrDcb);
|
||
|
||
//
|
||
// We call FatLookupFileAllocation with Vbo of 0xffffffff - 1.
|
||
//
|
||
|
||
FatLookupFileAllocation( IrpContext,
|
||
FcbOrDcb,
|
||
MAXULONG - 1,
|
||
&Lbo,
|
||
&ByteCount,
|
||
&DontCare,
|
||
&DontCare,
|
||
NULL );
|
||
|
||
//
|
||
// FileSize was set at Fcb creation time from the contents of the directory entry,
|
||
// and we are only now looking up the real length of the allocation chain. If it
|
||
// cannot be contained, this is trash. Probably more where that came from.
|
||
//
|
||
|
||
if (FcbOrDcb->Header.FileSize.LowPart > FcbOrDcb->Header.AllocationSize.LowPart) {
|
||
|
||
FatPopUpFileCorrupt( IrpContext, FcbOrDcb );
|
||
FatRaiseStatus( IrpContext, STATUS_FILE_CORRUPT_ERROR );
|
||
}
|
||
|
||
DebugTrace(-1, Dbg, "FatLookupFileAllocationSize -> (VOID)\n", 0);
|
||
return;
|
||
}
|
||
|
||
|
||
_Requires_lock_held_(_Global_critical_region_)
|
||
VOID
|
||
FatAllocateDiskSpace (
|
||
IN PIRP_CONTEXT IrpContext,
|
||
IN PVCB Vcb,
|
||
IN ULONG AbsoluteClusterHint,
|
||
IN PULONG ByteCount,
|
||
IN BOOLEAN ExactMatchRequired,
|
||
OUT PLARGE_MCB Mcb
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This procedure allocates additional disk space and builds an mcb
|
||
representing the newly allocated space. If the space cannot be
|
||
allocated then this procedure raises an appropriate status.
|
||
|
||
Searching starts from the hint index in the Vcb unless an alternative
|
||
non-zero hint is given in AlternateClusterHint. If we are using the
|
||
hint field in the Vcb, it is set to the cluster following our allocation
|
||
when we are done.
|
||
|
||
Disk space can only be allocated in cluster units so this procedure
|
||
will round up any byte count to the next cluster boundary.
|
||
|
||
Pictorially what is done is the following (where ! denotes the end of
|
||
the fat chain (i.e., FAT_CLUSTER_LAST)):
|
||
|
||
|
||
Mcb (empty)
|
||
|
||
becomes
|
||
|
||
Mcb |--a--|--b--|--c--!
|
||
|
||
^
|
||
ByteCount ----------+
|
||
|
||
Arguments:
|
||
|
||
Vcb - Supplies the VCB being modified
|
||
|
||
AbsoluteClusterHint - Supplies an alternate hint index to start the
|
||
search from. If this is zero we use, and update,
|
||
the Vcb hint field.
|
||
|
||
ByteCount - Supplies the number of bytes that we are requesting, and
|
||
receives the number of bytes that we got.
|
||
|
||
ExactMatchRequired - Caller should set this to TRUE if only the precise run requested
|
||
is acceptable.
|
||
|
||
Mcb - Receives the MCB describing the newly allocated disk space. The
|
||
caller passes in an initialized Mcb that is filled in by this procedure.
|
||
|
||
Return Value:
|
||
|
||
TRUE - Allocated ok
|
||
FALSE - Failed to allocate exactly as requested (=> ExactMatchRequired was TRUE)
|
||
|
||
--*/
|
||
|
||
{
|
||
UCHAR LogOfBytesPerCluster;
|
||
ULONG BytesPerCluster;
|
||
ULONG StartingCluster;
|
||
ULONG ClusterCount;
|
||
ULONG WindowRelativeHint;
|
||
#if DBG
|
||
ULONG PreviousClear = 0;
|
||
#endif
|
||
|
||
PFAT_WINDOW Window;
|
||
BOOLEAN Wait = FALSE;
|
||
BOOLEAN Result = TRUE;
|
||
|
||
PAGED_CODE();
|
||
|
||
DebugTrace(+1, Dbg, "FatAllocateDiskSpace\n", 0);
|
||
DebugTrace( 0, Dbg, " Vcb = %p\n", Vcb);
|
||
DebugTrace( 0, Dbg, " *ByteCount = %8lx\n", *ByteCount);
|
||
DebugTrace( 0, Dbg, " Mcb = %p\n", Mcb);
|
||
DebugTrace( 0, Dbg, " Hint = %8lx\n", AbsoluteClusterHint);
|
||
|
||
NT_ASSERT((AbsoluteClusterHint <= Vcb->AllocationSupport.NumberOfClusters + 2) && (1 != AbsoluteClusterHint));
|
||
|
||
//
|
||
// Make sure byte count is not zero
|
||
//
|
||
|
||
if (*ByteCount == 0) {
|
||
|
||
DebugTrace(0, Dbg, "Nothing to allocate.\n", 0);
|
||
|
||
DebugTrace(-1, Dbg, "FatAllocateDiskSpace -> (VOID)\n", 0);
|
||
return;
|
||
}
|
||
|
||
//
|
||
// Compute the cluster count based on the byte count, rounding up
|
||
// to the next cluster if there is any remainder. Note that the
|
||
// pathalogical case BytesCount == 0 has been eliminated above.
|
||
//
|
||
|
||
LogOfBytesPerCluster = Vcb->AllocationSupport.LogOfBytesPerCluster;
|
||
BytesPerCluster = 1 << LogOfBytesPerCluster;
|
||
|
||
*ByteCount = (*ByteCount + (BytesPerCluster - 1))
|
||
& ~(BytesPerCluster - 1);
|
||
|
||
//
|
||
// If ByteCount is NOW zero, then we were asked for the maximal
|
||
// filesize (or at least for bytes in the last allocatable sector).
|
||
//
|
||
|
||
if (*ByteCount == 0) {
|
||
|
||
*ByteCount = 0xffffffff;
|
||
ClusterCount = 1 << (32 - LogOfBytesPerCluster);
|
||
|
||
} else {
|
||
|
||
ClusterCount = (*ByteCount >> LogOfBytesPerCluster);
|
||
}
|
||
|
||
//
|
||
// Analysis tools don't figure out that ClusterCount is not zero because
|
||
// of the ByteCount == 0 checks, so give them a hint.
|
||
//
|
||
_Analysis_assume_(ClusterCount > 0);
|
||
|
||
//
|
||
// Make sure there are enough free clusters to start with, and
|
||
// take them now so that nobody else takes them from us.
|
||
//
|
||
|
||
ExAcquireResourceSharedLite(&Vcb->ChangeBitMapResource, TRUE);
|
||
FatLockFreeClusterBitMap( Vcb );
|
||
|
||
if (ClusterCount <= Vcb->AllocationSupport.NumberOfFreeClusters) {
|
||
|
||
Vcb->AllocationSupport.NumberOfFreeClusters -= ClusterCount;
|
||
|
||
} else {
|
||
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
ExReleaseResourceLite(&Vcb->ChangeBitMapResource);
|
||
|
||
DebugTrace(0, Dbg, "Disk Full. Raise Status.\n", 0);
|
||
FatRaiseStatus( IrpContext, STATUS_DISK_FULL );
|
||
}
|
||
|
||
//
|
||
// Did the caller supply a hint?
|
||
//
|
||
|
||
if ((0 != AbsoluteClusterHint) && (AbsoluteClusterHint < (Vcb->AllocationSupport.NumberOfClusters + 2))) {
|
||
|
||
if (Vcb->NumberOfWindows > 1) {
|
||
|
||
//
|
||
// If we're being called upon to allocate clusters outside the
|
||
// current window (which happens only via MoveFile), it's a problem.
|
||
// We address this by changing the current window to be the one which
|
||
// contains the alternate cluster hint. Note that if the user's
|
||
// request would cross a window boundary, he doesn't really get what
|
||
// he wanted.
|
||
//
|
||
|
||
if (AbsoluteClusterHint < Vcb->CurrentWindow->FirstCluster ||
|
||
AbsoluteClusterHint > Vcb->CurrentWindow->LastCluster) {
|
||
|
||
ULONG BucketNum = FatWindowOfCluster( AbsoluteClusterHint );
|
||
|
||
NT_ASSERT( BucketNum < Vcb->NumberOfWindows);
|
||
|
||
//
|
||
// Drop our shared lock on the ChangeBitMapResource, and pick it up again
|
||
// exclusive in preparation for making the window swap.
|
||
//
|
||
|
||
FatUnlockFreeClusterBitMap(Vcb);
|
||
ExReleaseResourceLite(&Vcb->ChangeBitMapResource);
|
||
ExAcquireResourceExclusiveLite(&Vcb->ChangeBitMapResource, TRUE);
|
||
FatLockFreeClusterBitMap(Vcb);
|
||
|
||
Window = &Vcb->Windows[BucketNum];
|
||
|
||
//
|
||
// Again, test the current window against the one we want - some other
|
||
// thread could have sneaked in behind our backs and kindly set it to the one
|
||
// we need, when we dropped and reacquired the ChangeBitMapResource above.
|
||
//
|
||
|
||
if (Window != Vcb->CurrentWindow) {
|
||
|
||
_SEH2_TRY {
|
||
|
||
Wait = BooleanFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT);
|
||
SetFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT);
|
||
|
||
//
|
||
// Change to the new window (update Vcb->CurrentWindow) and scan it
|
||
// to build up a freespace bitmap etc.
|
||
//
|
||
|
||
FatExamineFatEntries( IrpContext, Vcb,
|
||
0,
|
||
0,
|
||
FALSE,
|
||
Window,
|
||
NULL);
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
if (!Wait) {
|
||
|
||
ClearFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT);
|
||
}
|
||
|
||
if (_SEH2_AbnormalTermination()) {
|
||
|
||
//
|
||
// We will have raised as a result of failing to pick up the
|
||
// chunk of the FAT for this window move. Release our resources
|
||
// and return the cluster count to the volume.
|
||
//
|
||
|
||
Vcb->AllocationSupport.NumberOfFreeClusters += ClusterCount;
|
||
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
ExReleaseResourceLite(&Vcb->ChangeBitMapResource);
|
||
}
|
||
} _SEH2_END;
|
||
}
|
||
}
|
||
|
||
//
|
||
// Make the hint cluster number relative to the base of the current window...
|
||
//
|
||
// Currentwindow->Firstcluster is baised by +2 already, so we will lose the
|
||
// bias already in AbsoluteClusterHint. Put it back....
|
||
//
|
||
|
||
WindowRelativeHint = AbsoluteClusterHint - Vcb->CurrentWindow->FirstCluster + 2;
|
||
}
|
||
else {
|
||
|
||
//
|
||
// Only one 'window', ie fat16/12. No modification necessary.
|
||
//
|
||
|
||
WindowRelativeHint = AbsoluteClusterHint;
|
||
}
|
||
}
|
||
else {
|
||
|
||
//
|
||
// Either no hint supplied, or it was out of range, so grab one from the Vcb
|
||
//
|
||
// NOTE: Clusterhint in the Vcb is not guaranteed to be set (may be -1)
|
||
//
|
||
|
||
WindowRelativeHint = Vcb->ClusterHint;
|
||
AbsoluteClusterHint = 0;
|
||
|
||
//
|
||
// Vcb hint may not have been initialized yet. Force to valid cluster.
|
||
//
|
||
|
||
if (-1 == WindowRelativeHint) {
|
||
|
||
WindowRelativeHint = 2;
|
||
}
|
||
}
|
||
|
||
NT_ASSERT((WindowRelativeHint >= 2) && (WindowRelativeHint < Vcb->FreeClusterBitMap.SizeOfBitMap + 2));
|
||
|
||
//
|
||
// Keep track of the window we're allocating from, so we can clean
|
||
// up correctly if the current window changes after we unlock the
|
||
// bitmap.
|
||
//
|
||
|
||
Window = Vcb->CurrentWindow;
|
||
|
||
//
|
||
// Try to find a run of free clusters large enough for us.
|
||
//
|
||
|
||
StartingCluster = FatFindFreeClusterRun( IrpContext,
|
||
Vcb,
|
||
ClusterCount,
|
||
WindowRelativeHint );
|
||
//
|
||
// If the above call was successful, we can just update the fat
|
||
// and Mcb and exit. Otherwise we have to look for smaller free
|
||
// runs.
|
||
//
|
||
// This test is a bit funky. Note that the error return from
|
||
// RtlFindClearBits is -1, and adding two to that is 1.
|
||
//
|
||
|
||
if ((StartingCluster != 1) &&
|
||
((0 == AbsoluteClusterHint) || (StartingCluster == WindowRelativeHint))
|
||
) {
|
||
|
||
#if DBG
|
||
PreviousClear = RtlNumberOfClearBits( &Vcb->FreeClusterBitMap );
|
||
#endif // DBG
|
||
|
||
//
|
||
// Take the clusters we found, and unlock the bit map.
|
||
//
|
||
|
||
FatReserveClusters(IrpContext, Vcb, StartingCluster, ClusterCount);
|
||
|
||
Window->ClustersFree -= ClusterCount;
|
||
|
||
StartingCluster += Window->FirstCluster;
|
||
StartingCluster -= 2;
|
||
|
||
NT_ASSERT( PreviousClear - ClusterCount == Window->ClustersFree );
|
||
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
|
||
//
|
||
// Note that this call will never fail since there is always
|
||
// room for one entry in an empty Mcb.
|
||
//
|
||
|
||
FatAddMcbEntry( Vcb, Mcb,
|
||
0,
|
||
FatGetLboFromIndex( Vcb, StartingCluster ),
|
||
*ByteCount);
|
||
_SEH2_TRY {
|
||
|
||
//
|
||
// Update the fat.
|
||
//
|
||
|
||
FatAllocateClusters(IrpContext, Vcb,
|
||
StartingCluster,
|
||
ClusterCount);
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
DebugUnwind( FatAllocateDiskSpace );
|
||
|
||
//
|
||
// If the allocate clusters failed, remove the run from the Mcb,
|
||
// unreserve the clusters, and reset the free cluster count.
|
||
//
|
||
|
||
if (_SEH2_AbnormalTermination()) {
|
||
|
||
FatRemoveMcbEntry( Vcb, Mcb, 0, *ByteCount );
|
||
|
||
FatLockFreeClusterBitMap( Vcb );
|
||
|
||
// Only clear bits if the bitmap window is the same.
|
||
|
||
if (Window == Vcb->CurrentWindow) {
|
||
|
||
// Both values (startingcluster and window->firstcluster) are
|
||
// already biased by 2, so will cancel, so we need to add in the 2 again.
|
||
|
||
FatUnreserveClusters( IrpContext, Vcb,
|
||
StartingCluster - Window->FirstCluster + 2,
|
||
ClusterCount );
|
||
}
|
||
|
||
Window->ClustersFree += ClusterCount;
|
||
Vcb->AllocationSupport.NumberOfFreeClusters += ClusterCount;
|
||
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
}
|
||
|
||
ExReleaseResourceLite(&Vcb->ChangeBitMapResource);
|
||
} _SEH2_END;
|
||
|
||
} else {
|
||
|
||
//
|
||
// Note that Index is a zero-based window-relative number. When appropriate
|
||
// it'll get converted into a true cluster number and put in Cluster, which
|
||
// will be a volume relative true cluster number.
|
||
//
|
||
|
||
ULONG Index = 0;
|
||
ULONG Cluster = 0;
|
||
ULONG CurrentVbo = 0;
|
||
ULONG PriorLastCluster = 0;
|
||
ULONG BytesFound = 0;
|
||
|
||
ULONG ClustersFound = 0;
|
||
ULONG ClustersRemaining = 0;
|
||
|
||
BOOLEAN LockedBitMap = FALSE;
|
||
BOOLEAN SelectNextContigWindow = FALSE;
|
||
|
||
//
|
||
// Drop our shared lock on the ChangeBitMapResource, and pick it up again
|
||
// exclusive in preparation for making a window swap.
|
||
//
|
||
|
||
FatUnlockFreeClusterBitMap(Vcb);
|
||
ExReleaseResourceLite(&Vcb->ChangeBitMapResource);
|
||
ExAcquireResourceExclusiveLite(&Vcb->ChangeBitMapResource, TRUE);
|
||
FatLockFreeClusterBitMap(Vcb);
|
||
LockedBitMap = TRUE;
|
||
|
||
_SEH2_TRY {
|
||
|
||
if ( ExactMatchRequired && (1 == Vcb->NumberOfWindows)) {
|
||
|
||
//
|
||
// Give up right now, there are no more windows to search! RtlFindClearBits
|
||
// searchs the whole bitmap, so we would have found any contiguous run
|
||
// large enough.
|
||
//
|
||
|
||
try_leave( Result = FALSE);
|
||
}
|
||
|
||
//
|
||
// While the request is still incomplete, look for the largest
|
||
// run of free clusters, mark them taken, allocate the run in
|
||
// the Mcb and Fat, and if this isn't the first time through
|
||
// the loop link it to prior run on the fat. The Mcb will
|
||
// coalesce automatically.
|
||
//
|
||
|
||
ClustersRemaining = ClusterCount;
|
||
CurrentVbo = 0;
|
||
PriorLastCluster = 0;
|
||
|
||
while (ClustersRemaining != 0) {
|
||
|
||
//
|
||
// If we just entered the loop, the bit map is already locked
|
||
//
|
||
|
||
if ( !LockedBitMap ) {
|
||
|
||
FatLockFreeClusterBitMap( Vcb );
|
||
LockedBitMap = TRUE;
|
||
}
|
||
|
||
//
|
||
// Find the largest run of free clusters. If the run is
|
||
// bigger than we need, only use what we need. Note that
|
||
// this will then be the last while() iteration.
|
||
//
|
||
|
||
// 12/3/95: need to bias bitmap by 2 bits for the defrag
|
||
// hooks and the below macro became impossible to do without in-line
|
||
// procedures.
|
||
//
|
||
// ClustersFound = FatLongestFreeClusterRun( IrpContext, Vcb, &Index );
|
||
|
||
ClustersFound = 0;
|
||
|
||
if (!SelectNextContigWindow) {
|
||
|
||
if ( 0 != WindowRelativeHint) {
|
||
|
||
ULONG Desired = Vcb->FreeClusterBitMap.SizeOfBitMap - (WindowRelativeHint - 2);
|
||
|
||
//
|
||
// We will try to allocate contiguously. Try from the current hint the to
|
||
// end of current window. Don't try for more than we actually need.
|
||
//
|
||
|
||
if (Desired > ClustersRemaining) {
|
||
|
||
Desired = ClustersRemaining;
|
||
}
|
||
|
||
if (RtlAreBitsClear( &Vcb->FreeClusterBitMap,
|
||
WindowRelativeHint - 2,
|
||
Desired))
|
||
{
|
||
//
|
||
// Clusters from hint->...windowend are free. Take them.
|
||
//
|
||
|
||
Index = WindowRelativeHint - 2;
|
||
ClustersFound = Desired;
|
||
|
||
if (FatIsFat32(Vcb)) {
|
||
|
||
//
|
||
// We're now up against the end of the current window, so indicate that we
|
||
// want the next window in the sequence next time around. (If we're not up
|
||
// against the end of the window, then we got what we needed and won't be
|
||
// coming around again anyway).
|
||
//
|
||
|
||
SelectNextContigWindow = TRUE;
|
||
WindowRelativeHint = 2;
|
||
}
|
||
else {
|
||
|
||
//
|
||
// FAT 12/16 - we've run up against the end of the volume. Clear the
|
||
// hint, since we now have no idea where to look.
|
||
//
|
||
|
||
WindowRelativeHint = 0;
|
||
}
|
||
#if DBG
|
||
PreviousClear = RtlNumberOfClearBits( &Vcb->FreeClusterBitMap );
|
||
#endif // DBG
|
||
}
|
||
else {
|
||
|
||
if (ExactMatchRequired) {
|
||
|
||
//
|
||
// If our caller required an exact match, then we're hosed. Bail out now.
|
||
//
|
||
|
||
try_leave( Result = FALSE);
|
||
}
|
||
|
||
//
|
||
// Hint failed, drop back to pot luck
|
||
//
|
||
|
||
WindowRelativeHint = 0;
|
||
}
|
||
}
|
||
|
||
if ((0 == WindowRelativeHint) && (0 == ClustersFound)) {
|
||
|
||
if (ClustersRemaining <= Vcb->CurrentWindow->ClustersFree) {
|
||
|
||
//
|
||
// The remaining allocation could be satisfied entirely from this
|
||
// window. We will ask only for what we need, to try and avoid
|
||
// unnecessarily fragmenting large runs of space by always using
|
||
// (part of) the largest run we can find. This call will return the
|
||
// first run large enough.
|
||
//
|
||
|
||
Index = RtlFindClearBits( &Vcb->FreeClusterBitMap, ClustersRemaining, 0);
|
||
|
||
if (-1 != Index) {
|
||
|
||
ClustersFound = ClustersRemaining;
|
||
}
|
||
}
|
||
|
||
if (0 == ClustersFound) {
|
||
|
||
//
|
||
// Still nothing, so just take the largest free run we can find.
|
||
//
|
||
|
||
ClustersFound = RtlFindLongestRunClear( &Vcb->FreeClusterBitMap, &Index );
|
||
|
||
}
|
||
#if DBG
|
||
PreviousClear = RtlNumberOfClearBits( &Vcb->FreeClusterBitMap );
|
||
#endif // DBG
|
||
if (ClustersFound >= ClustersRemaining) {
|
||
|
||
ClustersFound = ClustersRemaining;
|
||
}
|
||
else {
|
||
|
||
//
|
||
// If we just ran up to the end of a window, set up a hint that
|
||
// we'd like the next consecutive window after this one. (FAT32 only)
|
||
//
|
||
|
||
if ( ((Index + ClustersFound) == Vcb->FreeClusterBitMap.SizeOfBitMap) &&
|
||
FatIsFat32( Vcb)
|
||
) {
|
||
|
||
SelectNextContigWindow = TRUE;
|
||
WindowRelativeHint = 2;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
if (ClustersFound == 0) {
|
||
|
||
ULONG FaveWindow = 0;
|
||
BOOLEAN SelectedWindow;
|
||
|
||
//
|
||
// If we found no free clusters on a single-window FAT,
|
||
// there was a bad problem with the free cluster count.
|
||
//
|
||
|
||
if (1 == Vcb->NumberOfWindows) {
|
||
|
||
#ifdef _MSC_VER
|
||
#pragma prefast( suppress: 28159, "we bugcheck here because our internal data structures are seriously corrupted if this happens" )
|
||
#endif
|
||
FatBugCheck( 0, 5, 0 );
|
||
}
|
||
|
||
//
|
||
// Switch to a new bucket. Possibly the next one if we're
|
||
// currently on a roll (allocating contiguously)
|
||
//
|
||
|
||
SelectedWindow = FALSE;
|
||
|
||
if ( SelectNextContigWindow) {
|
||
|
||
ULONG NextWindow;
|
||
|
||
NextWindow = (((ULONG)((PUCHAR)Vcb->CurrentWindow - (PUCHAR)Vcb->Windows)) / sizeof( FAT_WINDOW)) + 1;
|
||
|
||
if ((NextWindow < Vcb->NumberOfWindows) &&
|
||
( Vcb->Windows[ NextWindow].ClustersFree > 0)
|
||
) {
|
||
|
||
FaveWindow = NextWindow;
|
||
SelectedWindow = TRUE;
|
||
}
|
||
else {
|
||
|
||
if (ExactMatchRequired) {
|
||
|
||
//
|
||
// Some dope tried to allocate a run past the end of the volume...
|
||
//
|
||
|
||
try_leave( Result = FALSE);
|
||
}
|
||
|
||
//
|
||
// Give up on the contiguous allocation attempts
|
||
//
|
||
|
||
WindowRelativeHint = 0;
|
||
}
|
||
|
||
SelectNextContigWindow = FALSE;
|
||
}
|
||
|
||
if (!SelectedWindow) {
|
||
|
||
//
|
||
// Select a new window to begin allocating from
|
||
//
|
||
|
||
FaveWindow = FatSelectBestWindow( Vcb);
|
||
}
|
||
|
||
//
|
||
// By now we'd better have found a window with some free clusters
|
||
//
|
||
|
||
if (0 == Vcb->Windows[ FaveWindow].ClustersFree) {
|
||
|
||
#ifdef _MSC_VER
|
||
#pragma prefast( suppress: 28159, "we bugcheck here because our internal data structures are seriously corrupted if this happens" )
|
||
#endif
|
||
FatBugCheck( 0, 5, 1 );
|
||
}
|
||
|
||
Wait = BooleanFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT);
|
||
SetFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT);
|
||
|
||
FatExamineFatEntries( IrpContext, Vcb,
|
||
0,
|
||
0,
|
||
FALSE,
|
||
&Vcb->Windows[FaveWindow],
|
||
NULL);
|
||
|
||
if (!Wait) {
|
||
|
||
ClearFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT);
|
||
}
|
||
|
||
//
|
||
// Now we'll just go around the loop again, having switched windows,
|
||
// and allocate....
|
||
//
|
||
#if DBG
|
||
PreviousClear = RtlNumberOfClearBits( &Vcb->FreeClusterBitMap );
|
||
#endif //DBG
|
||
} // if (clustersfound == 0)
|
||
else {
|
||
|
||
//
|
||
// Take the clusters we found, convert our index to a cluster number
|
||
// and unlock the bit map.
|
||
//
|
||
|
||
Window = Vcb->CurrentWindow;
|
||
|
||
FatReserveClusters( IrpContext, Vcb, (Index + 2), ClustersFound );
|
||
|
||
Cluster = Index + Window->FirstCluster;
|
||
|
||
Window->ClustersFree -= ClustersFound;
|
||
NT_ASSERT( PreviousClear - ClustersFound == Window->ClustersFree );
|
||
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
LockedBitMap = FALSE;
|
||
|
||
//
|
||
// Add the newly alloced run to the Mcb.
|
||
//
|
||
|
||
BytesFound = ClustersFound << LogOfBytesPerCluster;
|
||
|
||
FatAddMcbEntry( Vcb, Mcb,
|
||
CurrentVbo,
|
||
FatGetLboFromIndex( Vcb, Cluster ),
|
||
BytesFound );
|
||
|
||
//
|
||
// Connect the last allocated run with this one, and allocate
|
||
// this run on the Fat.
|
||
//
|
||
|
||
if (PriorLastCluster != 0) {
|
||
|
||
FatSetFatEntry( IrpContext,
|
||
Vcb,
|
||
PriorLastCluster,
|
||
(FAT_ENTRY)Cluster );
|
||
}
|
||
|
||
//
|
||
// Update the fat
|
||
//
|
||
|
||
FatAllocateClusters( IrpContext, Vcb, Cluster, ClustersFound );
|
||
|
||
//
|
||
// Prepare for the next iteration.
|
||
//
|
||
|
||
CurrentVbo += BytesFound;
|
||
ClustersRemaining -= ClustersFound;
|
||
PriorLastCluster = Cluster + ClustersFound - 1;
|
||
}
|
||
} // while (clustersremaining)
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
DebugUnwind( FatAllocateDiskSpace );
|
||
|
||
ExReleaseResourceLite(&Vcb->ChangeBitMapResource);
|
||
|
||
//
|
||
// Is there any unwinding to do?
|
||
//
|
||
|
||
if ( _SEH2_AbnormalTermination() || (FALSE == Result)) {
|
||
|
||
//
|
||
// Flag to the caller that they're getting nothing
|
||
//
|
||
|
||
*ByteCount = 0;
|
||
|
||
//
|
||
// There are three places we could have taken this exception:
|
||
// when switching the window (FatExamineFatEntries), adding
|
||
// a found run to the Mcb (FatAddMcbEntry), or when writing
|
||
// the changes to the FAT (FatSetFatEntry). In the first case
|
||
// we don't have anything to unwind before deallocation, and
|
||
// can detect this by seeing if we have the ClusterBitmap
|
||
// mutex out.
|
||
|
||
if (!LockedBitMap) {
|
||
|
||
FatLockFreeClusterBitMap( Vcb );
|
||
|
||
//
|
||
// In these cases, we have the possiblity that the FAT
|
||
// window is still in place and we need to clear the bits.
|
||
// If the Mcb entry isn't there (we raised trying to add
|
||
// it), the effect of trying to remove it is a noop.
|
||
//
|
||
|
||
if (Window == Vcb->CurrentWindow) {
|
||
|
||
//
|
||
// Cluster reservation works on cluster 2 based window-relative
|
||
// numbers, so we must convert. The subtraction will lose the
|
||
// cluster 2 base, so bias the result.
|
||
//
|
||
|
||
FatUnreserveClusters( IrpContext, Vcb,
|
||
(Cluster - Window->FirstCluster) + 2,
|
||
ClustersFound );
|
||
}
|
||
|
||
//
|
||
// Note that FatDeallocateDiskSpace will take care of adjusting
|
||
// to account for the entries in the Mcb. All we have to account
|
||
// for is the last run that didn't make it.
|
||
//
|
||
|
||
Window->ClustersFree += ClustersFound;
|
||
Vcb->AllocationSupport.NumberOfFreeClusters += ClustersFound;
|
||
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
|
||
FatRemoveMcbEntry( Vcb, Mcb, CurrentVbo, BytesFound );
|
||
|
||
} else {
|
||
|
||
//
|
||
// Just drop the mutex now - we didn't manage to do anything
|
||
// that needs to be backed out.
|
||
//
|
||
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
}
|
||
|
||
_SEH2_TRY {
|
||
|
||
//
|
||
// Now we have tidied up, we are ready to just send the Mcb
|
||
// off to deallocate disk space
|
||
//
|
||
|
||
FatDeallocateDiskSpace( IrpContext, Vcb, Mcb, FALSE );
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
//
|
||
// Now finally (really), remove all the entries from the mcb
|
||
//
|
||
|
||
FatRemoveMcbEntry( Vcb, Mcb, 0, 0xFFFFFFFF );
|
||
} _SEH2_END;
|
||
}
|
||
|
||
DebugTrace(-1, Dbg, "FatAllocateDiskSpace -> (VOID)\n", 0);
|
||
|
||
} _SEH2_END; // finally
|
||
}
|
||
|
||
return;
|
||
}
|
||
|
||
|
||
|
||
//
|
||
// Limit our zeroing writes to 1 MB.
|
||
//
|
||
|
||
#define MAX_ZERO_MDL_SIZE (1*1024*1024)
|
||
|
||
_Requires_lock_held_(_Global_critical_region_)
|
||
VOID
|
||
FatDeallocateDiskSpace (
|
||
IN PIRP_CONTEXT IrpContext,
|
||
IN PVCB Vcb,
|
||
IN PLARGE_MCB Mcb,
|
||
IN BOOLEAN ZeroOnDeallocate
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This procedure deallocates the disk space denoted by an input
|
||
mcb. Note that the input MCB does not need to necessarily describe
|
||
a chain that ends with a FAT_CLUSTER_LAST entry.
|
||
|
||
Pictorially what is done is the following
|
||
|
||
Fat |--a--|--b--|--c--|
|
||
Mcb |--a--|--b--|--c--|
|
||
|
||
becomes
|
||
|
||
Fat |--0--|--0--|--0--|
|
||
Mcb |--a--|--b--|--c--|
|
||
|
||
Arguments:
|
||
|
||
Vcb - Supplies the VCB being modified
|
||
|
||
Mcb - Supplies the MCB describing the disk space to deallocate. Note
|
||
that Mcb is unchanged by this procedure.
|
||
|
||
|
||
Return Value:
|
||
|
||
None.
|
||
|
||
--*/
|
||
|
||
{
|
||
LBO Lbo;
|
||
VBO Vbo;
|
||
|
||
ULONG RunsInMcb;
|
||
ULONG ByteCount;
|
||
ULONG ClusterCount = 0;
|
||
ULONG ClusterIndex = 0;
|
||
ULONG McbIndex = 0;
|
||
|
||
UCHAR LogOfBytesPerCluster;
|
||
|
||
PFAT_WINDOW Window;
|
||
|
||
NTSTATUS ZeroingStatus = STATUS_SUCCESS;
|
||
|
||
PAGED_CODE();
|
||
|
||
DebugTrace(+1, Dbg, "FatDeallocateDiskSpace\n", 0);
|
||
DebugTrace( 0, Dbg, " Vcb = %p\n", Vcb);
|
||
DebugTrace( 0, Dbg, " Mcb = %p\n", Mcb);
|
||
|
||
LogOfBytesPerCluster = Vcb->AllocationSupport.LogOfBytesPerCluster;
|
||
|
||
RunsInMcb = FsRtlNumberOfRunsInLargeMcb( Mcb );
|
||
|
||
if ( RunsInMcb == 0 ) {
|
||
|
||
DebugTrace(-1, Dbg, "FatDeallocateDiskSpace -> (VOID)\n", 0);
|
||
return;
|
||
}
|
||
|
||
//
|
||
// If we are supposed to zero out the allocation before freeing it, do so.
|
||
//
|
||
|
||
if (ZeroOnDeallocate) {
|
||
|
||
_SEH2_TRY {
|
||
|
||
PIRP IoIrp;
|
||
KEVENT IoEvent;
|
||
IO_STATUS_BLOCK Iosb;
|
||
PVOID Buffer = NULL;
|
||
PMDL Mdl;
|
||
ULONG ByteCountToZero;
|
||
ULONG MdlSizeMapped;
|
||
|
||
//
|
||
// Issue the writes down for each run in the Mcb
|
||
//
|
||
|
||
KeInitializeEvent( &IoEvent,
|
||
NotificationEvent,
|
||
FALSE );
|
||
|
||
for ( McbIndex = 0; McbIndex < RunsInMcb; McbIndex++ ) {
|
||
|
||
FatGetNextMcbEntry( Vcb, Mcb, McbIndex, &Vbo, &Lbo, &ByteCount );
|
||
|
||
//
|
||
// Assert that Fat files have no holes.
|
||
//
|
||
|
||
NT_ASSERT( Lbo != 0 );
|
||
|
||
//
|
||
// Setup our MDL for the this run.
|
||
//
|
||
|
||
if (ByteCount > MAX_ZERO_MDL_SIZE) {
|
||
Mdl = FatBuildZeroMdl( IrpContext, MAX_ZERO_MDL_SIZE);
|
||
} else {
|
||
Mdl = FatBuildZeroMdl( IrpContext, ByteCount);
|
||
}
|
||
|
||
if (!Mdl) {
|
||
ZeroingStatus = STATUS_INSUFFICIENT_RESOURCES;
|
||
goto try_exit;
|
||
}
|
||
|
||
_SEH2_TRY {
|
||
|
||
//
|
||
// Map the MDL.
|
||
//
|
||
|
||
Buffer = MmGetSystemAddressForMdlSafe(Mdl, HighPagePriority|MdlMappingNoExecute);
|
||
if (!Buffer) {
|
||
NT_ASSERT( FALSE );
|
||
ZeroingStatus = STATUS_INSUFFICIENT_RESOURCES;
|
||
goto try_exit2;
|
||
}
|
||
|
||
//
|
||
// We might not have not been able to get an MDL big enough to map the whole
|
||
// run. In this case, break up the write.
|
||
//
|
||
|
||
MdlSizeMapped = min( ByteCount, Mdl->ByteCount );
|
||
ByteCountToZero = ByteCount;
|
||
|
||
//
|
||
// Loop until there are no bytes left to write
|
||
//
|
||
|
||
while (ByteCountToZero != 0) {
|
||
|
||
//
|
||
// Write zeros to each run.
|
||
//
|
||
|
||
KeClearEvent( &IoEvent );
|
||
|
||
IoIrp = IoBuildSynchronousFsdRequest( IRP_MJ_WRITE,
|
||
Vcb->TargetDeviceObject,
|
||
Buffer,
|
||
MdlSizeMapped,
|
||
(PLARGE_INTEGER)&Lbo,
|
||
&IoEvent,
|
||
&Iosb );
|
||
|
||
if (IoIrp == NULL) {
|
||
NT_ASSERT( FALSE );
|
||
ZeroingStatus = STATUS_INSUFFICIENT_RESOURCES;
|
||
goto try_exit2;
|
||
}
|
||
|
||
//
|
||
// Set a flag indicating that we want to write through any
|
||
// cache on the controller. This eliminates the need for
|
||
// an explicit flush-device after the write.
|
||
//
|
||
|
||
SetFlag( IoGetNextIrpStackLocation(IoIrp)->Flags, SL_WRITE_THROUGH );
|
||
|
||
ZeroingStatus = IoCallDriver( Vcb->TargetDeviceObject, IoIrp );
|
||
|
||
if (ZeroingStatus == STATUS_PENDING) {
|
||
|
||
(VOID)KeWaitForSingleObject( &IoEvent,
|
||
Executive,
|
||
KernelMode,
|
||
FALSE,
|
||
(PLARGE_INTEGER)NULL );
|
||
|
||
ZeroingStatus = Iosb.Status;
|
||
}
|
||
|
||
if (!NT_SUCCESS( ZeroingStatus )) {
|
||
NT_ASSERT( FALSE );
|
||
goto try_exit2;
|
||
}
|
||
|
||
//
|
||
// Increment the starting offset where we will zero.
|
||
//
|
||
|
||
Lbo += MdlSizeMapped;
|
||
|
||
//
|
||
// Decrement ByteCount
|
||
//
|
||
|
||
ByteCountToZero -= MdlSizeMapped;
|
||
|
||
if (ByteCountToZero < MdlSizeMapped) {
|
||
MdlSizeMapped = ByteCountToZero;
|
||
}
|
||
|
||
}
|
||
|
||
try_exit2:
|
||
|
||
NOTHING;
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
if (!FlagOn( Mdl->MdlFlags, MDL_SOURCE_IS_NONPAGED_POOL) &&
|
||
FlagOn( Mdl->MdlFlags, MDL_MAPPED_TO_SYSTEM_VA )) {
|
||
|
||
MmUnmapLockedPages( Mdl->MappedSystemVa, Mdl );
|
||
}
|
||
IoFreeMdl( Mdl );
|
||
} _SEH2_END;
|
||
|
||
}
|
||
|
||
try_exit:
|
||
|
||
NOTHING;
|
||
|
||
} _SEH2_EXCEPT(FatExceptionFilter( NULL, _SEH2_GetExceptionInformation() )) {
|
||
|
||
//
|
||
// If we failed to zero for some reason, still go ahead and deallocate
|
||
// the clusters. Otherwise we'll leak space from the volume.
|
||
//
|
||
|
||
ZeroingStatus = _SEH2_GetExceptionCode();
|
||
|
||
} _SEH2_END;
|
||
|
||
}
|
||
|
||
NT_ASSERT( NT_SUCCESS(ZeroingStatus) );
|
||
|
||
_SEH2_TRY {
|
||
|
||
//
|
||
// Run though the Mcb, freeing all the runs in the fat.
|
||
//
|
||
// We do this in two steps (first update the fat, then the bitmap
|
||
// (which can't fail)) to prevent other people from taking clusters
|
||
// that we need to re-allocate in the event of unwind.
|
||
//
|
||
|
||
ExAcquireResourceSharedLite(&Vcb->ChangeBitMapResource, TRUE);
|
||
|
||
RunsInMcb = FsRtlNumberOfRunsInLargeMcb( Mcb );
|
||
|
||
for ( McbIndex = 0; McbIndex < RunsInMcb; McbIndex++ ) {
|
||
|
||
FatGetNextMcbEntry( Vcb, Mcb, McbIndex, &Vbo, &Lbo, &ByteCount );
|
||
|
||
//
|
||
// Assert that Fat files have no holes.
|
||
//
|
||
|
||
NT_ASSERT( Lbo != 0 );
|
||
|
||
//
|
||
// Write FAT_CLUSTER_AVAILABLE to each cluster in the run.
|
||
//
|
||
|
||
if (ByteCount == 0xFFFFFFFF) {
|
||
|
||
//
|
||
// Special case the computation of ClusterCout
|
||
// when file is of max size (4GiB - 1).
|
||
//
|
||
|
||
ClusterCount = (1 << (32 - LogOfBytesPerCluster));
|
||
|
||
} else {
|
||
|
||
ClusterCount = ByteCount >> LogOfBytesPerCluster;
|
||
}
|
||
|
||
ClusterIndex = FatGetIndexFromLbo( Vcb, Lbo );
|
||
|
||
FatFreeClusters( IrpContext, Vcb, ClusterIndex, ClusterCount );
|
||
}
|
||
|
||
//
|
||
// From now on, nothing can go wrong .... (as in raise)
|
||
//
|
||
|
||
FatLockFreeClusterBitMap( Vcb );
|
||
|
||
for ( McbIndex = 0; McbIndex < RunsInMcb; McbIndex++ ) {
|
||
|
||
ULONG ClusterEnd;
|
||
ULONG MyStart, MyLength, count;
|
||
#if DBG
|
||
#ifndef __REACTOS__
|
||
ULONG PreviousClear = 0;
|
||
#endif
|
||
ULONG i = 0;
|
||
#endif
|
||
|
||
FatGetNextMcbEntry( Vcb, Mcb, McbIndex, &Vbo, &Lbo, &ByteCount );
|
||
|
||
//
|
||
// Mark the bits clear in the FreeClusterBitMap.
|
||
//
|
||
|
||
if (ByteCount == 0xFFFFFFFF) {
|
||
|
||
//
|
||
// Special case the computation of ClusterCout
|
||
// when file is of max size (2^32 - 1).
|
||
//
|
||
|
||
ClusterCount = (1 << (32 - LogOfBytesPerCluster));
|
||
|
||
} else {
|
||
|
||
ClusterCount = ByteCount >> LogOfBytesPerCluster;
|
||
}
|
||
|
||
ClusterIndex = FatGetIndexFromLbo( Vcb, Lbo );
|
||
|
||
Window = Vcb->CurrentWindow;
|
||
|
||
//
|
||
// If we've divided the bitmap, elide bitmap manipulation for
|
||
// runs that are outside the current bucket.
|
||
//
|
||
|
||
ClusterEnd = ClusterIndex + ClusterCount - 1;
|
||
|
||
if (!(ClusterIndex > Window->LastCluster ||
|
||
ClusterEnd < Window->FirstCluster)) {
|
||
|
||
//
|
||
// The run being freed overlaps the current bucket, so we'll
|
||
// have to clear some bits.
|
||
//
|
||
|
||
if (ClusterIndex < Window->FirstCluster &&
|
||
ClusterEnd > Window->LastCluster) {
|
||
|
||
MyStart = Window->FirstCluster;
|
||
MyLength = Window->LastCluster - Window->FirstCluster + 1;
|
||
|
||
} else if (ClusterIndex < Window->FirstCluster) {
|
||
|
||
MyStart = Window->FirstCluster;
|
||
MyLength = ClusterEnd - Window->FirstCluster + 1;
|
||
|
||
} else {
|
||
|
||
//
|
||
// The range being freed starts in the bucket, and may possibly
|
||
// extend beyond the bucket.
|
||
//
|
||
|
||
MyStart = ClusterIndex;
|
||
|
||
if (ClusterEnd <= Window->LastCluster) {
|
||
|
||
MyLength = ClusterCount;
|
||
|
||
} else {
|
||
|
||
MyLength = Window->LastCluster - ClusterIndex + 1;
|
||
}
|
||
}
|
||
|
||
if (MyLength == 0) {
|
||
|
||
continue;
|
||
}
|
||
|
||
#if DBG
|
||
#ifndef __REACTOS__
|
||
#ifdef _MSC_VER
|
||
#pragma prefast( suppress:28931, "this is DBG build only" )
|
||
#endif
|
||
PreviousClear = RtlNumberOfClearBits( &Vcb->FreeClusterBitMap );
|
||
#endif
|
||
|
||
|
||
//
|
||
// Verify that the Bits are all really set.
|
||
//
|
||
|
||
NT_ASSERT( MyStart + MyLength - Window->FirstCluster <= Vcb->FreeClusterBitMap.SizeOfBitMap );
|
||
|
||
for (i = 0; i < MyLength; i++) {
|
||
|
||
NT_ASSERT( RtlCheckBit(&Vcb->FreeClusterBitMap,
|
||
MyStart - Window->FirstCluster + i) == 1 );
|
||
}
|
||
#endif // DBG
|
||
|
||
FatUnreserveClusters( IrpContext, Vcb,
|
||
MyStart - Window->FirstCluster + 2,
|
||
MyLength );
|
||
}
|
||
|
||
//
|
||
// Adjust the ClustersFree count for each bitmap window, even the ones
|
||
// that are not the current window.
|
||
//
|
||
|
||
if (FatIsFat32(Vcb)) {
|
||
|
||
Window = &Vcb->Windows[FatWindowOfCluster( ClusterIndex )];
|
||
|
||
} else {
|
||
|
||
Window = &Vcb->Windows[0];
|
||
}
|
||
|
||
MyStart = ClusterIndex;
|
||
|
||
for (MyLength = ClusterCount; MyLength > 0; MyLength -= count) {
|
||
|
||
count = FatMin(Window->LastCluster - MyStart + 1, MyLength);
|
||
Window->ClustersFree += count;
|
||
|
||
//
|
||
// If this was not the last window this allocation spanned,
|
||
// advance to the next.
|
||
//
|
||
|
||
if (MyLength != count) {
|
||
|
||
Window++;
|
||
MyStart = Window->FirstCluster;
|
||
}
|
||
}
|
||
|
||
//
|
||
// Deallocation is now complete. Adjust the free cluster count.
|
||
//
|
||
|
||
Vcb->AllocationSupport.NumberOfFreeClusters += ClusterCount;
|
||
}
|
||
|
||
#if DBG
|
||
if (Vcb->CurrentWindow->ClustersFree !=
|
||
RtlNumberOfClearBits(&Vcb->FreeClusterBitMap)) {
|
||
|
||
DbgPrint("%x vs %x\n", Vcb->CurrentWindow->ClustersFree,
|
||
RtlNumberOfClearBits(&Vcb->FreeClusterBitMap));
|
||
|
||
DbgPrint("%x for %x\n", ClusterIndex, ClusterCount);
|
||
}
|
||
#endif
|
||
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
DebugUnwind( FatDeallocateDiskSpace );
|
||
|
||
//
|
||
// Is there any unwinding to do?
|
||
//
|
||
|
||
ExReleaseResourceLite(&Vcb->ChangeBitMapResource);
|
||
|
||
if ( _SEH2_AbnormalTermination() ) {
|
||
|
||
LBO LocalLbo;
|
||
VBO LocalVbo;
|
||
|
||
ULONG Index;
|
||
ULONG Clusters;
|
||
ULONG FatIndex;
|
||
ULONG PriorLastIndex;
|
||
|
||
//
|
||
// For each entry we already deallocated, reallocate it,
|
||
// chaining together as nessecary. Note that we continue
|
||
// up to and including the last "for" iteration even though
|
||
// the SetFatRun could not have been successful. This
|
||
// allows us a convienent way to re-link the final successful
|
||
// SetFatRun.
|
||
//
|
||
// It is possible that the reason we got here will prevent us
|
||
// from succeeding in this operation.
|
||
//
|
||
|
||
PriorLastIndex = 0;
|
||
|
||
for (Index = 0; Index <= McbIndex; Index++) {
|
||
|
||
FatGetNextMcbEntry(Vcb, Mcb, Index, &LocalVbo, &LocalLbo, &ByteCount);
|
||
|
||
if (ByteCount == 0xFFFFFFFF) {
|
||
|
||
//
|
||
// Special case the computation of ClusterCout
|
||
// when file is of max size (2^32 - 1).
|
||
//
|
||
|
||
Clusters = (1 << (32 - LogOfBytesPerCluster));
|
||
|
||
} else {
|
||
|
||
Clusters = ByteCount >> LogOfBytesPerCluster;
|
||
}
|
||
|
||
FatIndex = FatGetIndexFromLbo( Vcb, LocalLbo );
|
||
|
||
//
|
||
// We must always restore the prior iteration's last
|
||
// entry, pointing it to the first cluster of this run.
|
||
//
|
||
|
||
if (PriorLastIndex != 0) {
|
||
|
||
FatSetFatEntry( IrpContext,
|
||
Vcb,
|
||
PriorLastIndex,
|
||
(FAT_ENTRY)FatIndex );
|
||
}
|
||
|
||
//
|
||
// If this is not the last entry (the one that failed)
|
||
// then reallocate the disk space on the fat.
|
||
//
|
||
|
||
if ( Index < McbIndex ) {
|
||
|
||
FatAllocateClusters(IrpContext, Vcb, FatIndex, Clusters);
|
||
|
||
PriorLastIndex = FatIndex + Clusters - 1;
|
||
}
|
||
}
|
||
}
|
||
|
||
DebugTrace(-1, Dbg, "FatDeallocateDiskSpace -> (VOID)\n", 0);
|
||
} _SEH2_END;
|
||
|
||
return;
|
||
}
|
||
|
||
|
||
_Requires_lock_held_(_Global_critical_region_)
|
||
VOID
|
||
FatSplitAllocation (
|
||
IN PIRP_CONTEXT IrpContext,
|
||
IN PVCB Vcb,
|
||
IN OUT PLARGE_MCB Mcb,
|
||
IN VBO SplitAtVbo,
|
||
OUT PLARGE_MCB RemainingMcb
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This procedure takes a single mcb and splits its allocation into
|
||
two separate allocation units. The separation must only be done
|
||
on cluster boundaries, otherwise we bugcheck.
|
||
|
||
On the disk this actually works by inserting a FAT_CLUSTER_LAST into
|
||
the last index of the first part being split out.
|
||
|
||
Pictorially what is done is the following (where ! denotes the end of
|
||
the fat chain (i.e., FAT_CLUSTER_LAST)):
|
||
|
||
|
||
Mcb |--a--|--b--|--c--|--d--|--e--|--f--|
|
||
|
||
^
|
||
SplitAtVbo ---------------------+
|
||
|
||
RemainingMcb (empty)
|
||
|
||
becomes
|
||
|
||
Mcb |--a--|--b--|--c--!
|
||
|
||
|
||
RemainingMcb |--d--|--e--|--f--|
|
||
|
||
Arguments:
|
||
|
||
Vcb - Supplies the VCB being modified
|
||
|
||
Mcb - Supplies the MCB describing the allocation being split into
|
||
two parts. Upon return this Mcb now contains the first chain.
|
||
|
||
SplitAtVbo - Supplies the VBO of the first byte for the second chain
|
||
that we creating.
|
||
|
||
RemainingMcb - Receives the MCB describing the second chain of allocated
|
||
disk space. The caller passes in an initialized Mcb that
|
||
is filled in by this procedure STARTING AT VBO 0.
|
||
|
||
Return Value:
|
||
|
||
VOID - TRUE if the operation completed and FALSE if it had to
|
||
block but could not.
|
||
|
||
--*/
|
||
|
||
{
|
||
VBO SourceVbo;
|
||
VBO TargetVbo;
|
||
VBO DontCare;
|
||
|
||
LBO Lbo;
|
||
|
||
ULONG ByteCount;
|
||
|
||
#if DBG
|
||
ULONG BytesPerCluster;
|
||
#endif
|
||
|
||
PAGED_CODE();
|
||
|
||
DebugTrace(+1, Dbg, "FatSplitAllocation\n", 0);
|
||
DebugTrace( 0, Dbg, " Vcb = %p\n", Vcb);
|
||
DebugTrace( 0, Dbg, " Mcb = %p\n", Mcb);
|
||
DebugTrace( 0, Dbg, " SplitAtVbo = %8lx\n", SplitAtVbo);
|
||
DebugTrace( 0, Dbg, " RemainingMcb = %p\n", RemainingMcb);
|
||
|
||
#if DBG
|
||
BytesPerCluster = 1 << Vcb->AllocationSupport.LogOfBytesPerCluster;
|
||
#endif
|
||
|
||
//
|
||
// Assert that the split point is cluster alligned
|
||
//
|
||
|
||
NT_ASSERT( (SplitAtVbo & (BytesPerCluster - 1)) == 0 );
|
||
|
||
//
|
||
// We should never be handed an empty source MCB and asked to split
|
||
// at a non zero point.
|
||
//
|
||
|
||
NT_ASSERT( !((0 != SplitAtVbo) && (0 == FsRtlNumberOfRunsInLargeMcb( Mcb))));
|
||
|
||
//
|
||
// Assert we were given an empty target Mcb.
|
||
//
|
||
|
||
//
|
||
// This assert is commented out to avoid hitting in the Ea error
|
||
// path. In that case we will be using the same Mcb's to split the
|
||
// allocation that we used to merge them. The target Mcb will contain
|
||
// the runs that the split will attempt to insert.
|
||
//
|
||
//
|
||
// NT_ASSERT( FsRtlNumberOfRunsInMcb( RemainingMcb ) == 0 );
|
||
//
|
||
|
||
_SEH2_TRY {
|
||
|
||
//
|
||
// Move the runs after SplitAtVbo from the souce to the target
|
||
//
|
||
|
||
SourceVbo = SplitAtVbo;
|
||
TargetVbo = 0;
|
||
|
||
while (FatLookupMcbEntry(Vcb, Mcb, SourceVbo, &Lbo, &ByteCount, NULL)) {
|
||
|
||
FatAddMcbEntry( Vcb, RemainingMcb, TargetVbo, Lbo, ByteCount );
|
||
|
||
FatRemoveMcbEntry( Vcb, Mcb, SourceVbo, ByteCount );
|
||
|
||
TargetVbo += ByteCount;
|
||
SourceVbo += ByteCount;
|
||
|
||
//
|
||
// If SourceVbo overflows, we were actually snipping off the end
|
||
// of the maximal file ... and are now done.
|
||
//
|
||
|
||
if (SourceVbo == 0) {
|
||
|
||
break;
|
||
}
|
||
}
|
||
|
||
//
|
||
// Mark the last pre-split cluster as a FAT_LAST_CLUSTER
|
||
//
|
||
|
||
if ( SplitAtVbo != 0 ) {
|
||
|
||
FatLookupLastMcbEntry( Vcb, Mcb, &DontCare, &Lbo, NULL );
|
||
|
||
FatSetFatEntry( IrpContext,
|
||
Vcb,
|
||
FatGetIndexFromLbo( Vcb, Lbo ),
|
||
FAT_CLUSTER_LAST );
|
||
}
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
DebugUnwind( FatSplitAllocation );
|
||
|
||
//
|
||
// If we got an exception, we must glue back together the Mcbs
|
||
//
|
||
|
||
if ( _SEH2_AbnormalTermination() ) {
|
||
|
||
TargetVbo = SplitAtVbo;
|
||
SourceVbo = 0;
|
||
|
||
while (FatLookupMcbEntry(Vcb, RemainingMcb, SourceVbo, &Lbo, &ByteCount, NULL)) {
|
||
|
||
FatAddMcbEntry( Vcb, Mcb, TargetVbo, Lbo, ByteCount );
|
||
|
||
FatRemoveMcbEntry( Vcb, RemainingMcb, SourceVbo, ByteCount );
|
||
|
||
TargetVbo += ByteCount;
|
||
SourceVbo += ByteCount;
|
||
}
|
||
}
|
||
|
||
DebugTrace(-1, Dbg, "FatSplitAllocation -> (VOID)\n", 0);
|
||
} _SEH2_END;
|
||
|
||
return;
|
||
}
|
||
|
||
|
||
_Requires_lock_held_(_Global_critical_region_)
|
||
VOID
|
||
FatMergeAllocation (
|
||
IN PIRP_CONTEXT IrpContext,
|
||
IN PVCB Vcb,
|
||
IN OUT PLARGE_MCB Mcb,
|
||
IN PLARGE_MCB SecondMcb
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine takes two separate allocations described by two MCBs and
|
||
joins them together into one allocation.
|
||
|
||
Pictorially what is done is the following (where ! denotes the end of
|
||
the fat chain (i.e., FAT_CLUSTER_LAST)):
|
||
|
||
|
||
Mcb |--a--|--b--|--c--!
|
||
|
||
SecondMcb |--d--|--e--|--f--|
|
||
|
||
becomes
|
||
|
||
Mcb |--a--|--b--|--c--|--d--|--e--|--f--|
|
||
|
||
SecondMcb |--d--|--e--|--f--|
|
||
|
||
|
||
Arguments:
|
||
|
||
Vcb - Supplies the VCB being modified
|
||
|
||
Mcb - Supplies the MCB of the first allocation that is being modified.
|
||
Upon return this Mcb will also describe the newly enlarged
|
||
allocation
|
||
|
||
SecondMcb - Supplies the ZERO VBO BASED MCB of the second allocation
|
||
that is being appended to the first allocation. This
|
||
procedure leaves SecondMcb unchanged.
|
||
|
||
Return Value:
|
||
|
||
VOID - TRUE if the operation completed and FALSE if it had to
|
||
block but could not.
|
||
|
||
--*/
|
||
|
||
{
|
||
VBO SpliceVbo = 0;
|
||
LBO SpliceLbo;
|
||
|
||
VBO SourceVbo;
|
||
VBO TargetVbo = 0;
|
||
|
||
LBO Lbo;
|
||
|
||
ULONG ByteCount;
|
||
|
||
PAGED_CODE();
|
||
|
||
DebugTrace(+1, Dbg, "FatMergeAllocation\n", 0);
|
||
DebugTrace( 0, Dbg, " Vcb = %p\n", Vcb);
|
||
DebugTrace( 0, Dbg, " Mcb = %p\n", Mcb);
|
||
DebugTrace( 0, Dbg, " SecondMcb = %p\n", SecondMcb);
|
||
|
||
_SEH2_TRY {
|
||
|
||
//
|
||
// Append the runs from SecondMcb to Mcb
|
||
//
|
||
|
||
(void)FatLookupLastMcbEntry( Vcb, Mcb, &SpliceVbo, &SpliceLbo, NULL );
|
||
|
||
SourceVbo = 0;
|
||
TargetVbo = SpliceVbo + 1;
|
||
|
||
while (FatLookupMcbEntry(Vcb, SecondMcb, SourceVbo, &Lbo, &ByteCount, NULL)) {
|
||
|
||
FatAddMcbEntry( Vcb, Mcb, TargetVbo, Lbo, ByteCount );
|
||
|
||
SourceVbo += ByteCount;
|
||
TargetVbo += ByteCount;
|
||
}
|
||
|
||
//
|
||
// Link the last pre-merge cluster to the first cluster of SecondMcb
|
||
//
|
||
|
||
FatLookupMcbEntry( Vcb, SecondMcb, 0, &Lbo, (PULONG)NULL, NULL );
|
||
|
||
FatSetFatEntry( IrpContext,
|
||
Vcb,
|
||
FatGetIndexFromLbo( Vcb, SpliceLbo ),
|
||
(FAT_ENTRY)FatGetIndexFromLbo( Vcb, Lbo ) );
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
DebugUnwind( FatMergeAllocation );
|
||
|
||
//
|
||
// If we got an exception, we must remove the runs added to Mcb
|
||
//
|
||
|
||
if ( _SEH2_AbnormalTermination() ) {
|
||
|
||
ULONG CutLength;
|
||
|
||
if ((CutLength = TargetVbo - (SpliceVbo + 1)) != 0) {
|
||
|
||
FatRemoveMcbEntry( Vcb, Mcb, SpliceVbo + 1, CutLength);
|
||
}
|
||
}
|
||
|
||
DebugTrace(-1, Dbg, "FatMergeAllocation -> (VOID)\n", 0);
|
||
} _SEH2_END;
|
||
|
||
return;
|
||
}
|
||
|
||
|
||
//
|
||
// Internal support routine
|
||
//
|
||
|
||
CLUSTER_TYPE
|
||
FatInterpretClusterType (
|
||
IN PVCB Vcb,
|
||
IN FAT_ENTRY Entry
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This procedure tells the caller how to interpret the input fat table
|
||
entry. It will indicate if the fat cluster is available, resereved,
|
||
bad, the last one, or the another fat index. This procedure can deal
|
||
with both 12 and 16 bit fat.
|
||
|
||
Arguments:
|
||
|
||
Vcb - Supplies the Vcb to examine, yields 12/16 bit info
|
||
|
||
Entry - Supplies the fat entry to examine
|
||
|
||
Return Value:
|
||
|
||
CLUSTER_TYPE - Is the type of the input Fat entry
|
||
|
||
--*/
|
||
|
||
{
|
||
DebugTrace(+1, Dbg, "InterpretClusterType\n", 0);
|
||
DebugTrace( 0, Dbg, " Vcb = %p\n", Vcb);
|
||
DebugTrace( 0, Dbg, " Entry = %8lx\n", Entry);
|
||
|
||
PAGED_CODE();
|
||
|
||
switch(Vcb->AllocationSupport.FatIndexBitSize ) {
|
||
case 32:
|
||
Entry &= FAT32_ENTRY_MASK;
|
||
break;
|
||
|
||
case 12:
|
||
NT_ASSERT( Entry <= 0xfff );
|
||
if (Entry >= 0x0ff0) {
|
||
Entry |= 0x0FFFF000;
|
||
}
|
||
break;
|
||
|
||
default:
|
||
case 16:
|
||
NT_ASSERT( Entry <= 0xffff );
|
||
if (Entry >= 0x0fff0) {
|
||
Entry |= 0x0FFF0000;
|
||
}
|
||
break;
|
||
}
|
||
|
||
if (Entry == FAT_CLUSTER_AVAILABLE) {
|
||
|
||
DebugTrace(-1, Dbg, "FatInterpretClusterType -> FatClusterAvailable\n", 0);
|
||
|
||
return FatClusterAvailable;
|
||
|
||
} else if (Entry < FAT_CLUSTER_RESERVED) {
|
||
|
||
DebugTrace(-1, Dbg, "FatInterpretClusterType -> FatClusterNext\n", 0);
|
||
|
||
return FatClusterNext;
|
||
|
||
} else if (Entry < FAT_CLUSTER_BAD) {
|
||
|
||
DebugTrace(-1, Dbg, "FatInterpretClusterType -> FatClusterReserved\n", 0);
|
||
|
||
return FatClusterReserved;
|
||
|
||
} else if (Entry == FAT_CLUSTER_BAD) {
|
||
|
||
DebugTrace(-1, Dbg, "FatInterpretClusterType -> FatClusterBad\n", 0);
|
||
|
||
return FatClusterBad;
|
||
|
||
} else {
|
||
|
||
DebugTrace(-1, Dbg, "FatInterpretClusterType -> FatClusterLast\n", 0);
|
||
|
||
return FatClusterLast;
|
||
}
|
||
}
|
||
|
||
|
||
//
|
||
// Internal support routine
|
||
//
|
||
|
||
VOID
|
||
FatLookupFatEntry (
|
||
IN PIRP_CONTEXT IrpContext,
|
||
IN PVCB Vcb,
|
||
IN ULONG FatIndex,
|
||
IN OUT PULONG FatEntry,
|
||
IN OUT PFAT_ENUMERATION_CONTEXT Context
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine takes an index into the fat and gives back the value
|
||
in the Fat at this index. At any given time, for a 16 bit fat, this
|
||
routine allows only one page per volume of the fat to be pinned in
|
||
memory. For a 12 bit bit fat, the entire fat (max 6k) is pinned. This
|
||
extra layer of caching makes the vast majority of requests very
|
||
fast. The context for this caching stored in a structure in the Vcb.
|
||
|
||
Arguments:
|
||
|
||
Vcb - Supplies the Vcb to examine, yields 12/16 bit info,
|
||
fat access context, etc.
|
||
|
||
FatIndex - Supplies the fat index to examine.
|
||
|
||
FatEntry - Receives the fat entry pointed to by FatIndex. Note that
|
||
it must point to non-paged pool.
|
||
|
||
Context - This structure keeps track of a page of pinned fat between calls.
|
||
|
||
--*/
|
||
|
||
{
|
||
PAGED_CODE();
|
||
|
||
DebugTrace(+1, Dbg, "FatLookupFatEntry\n", 0);
|
||
DebugTrace( 0, Dbg, " Vcb = %p\n", Vcb);
|
||
DebugTrace( 0, Dbg, " FatIndex = %4x\n", FatIndex);
|
||
DebugTrace( 0, Dbg, " FatEntry = %8lx\n", FatEntry);
|
||
|
||
//
|
||
// Make sure they gave us a valid fat index.
|
||
//
|
||
|
||
FatVerifyIndexIsValid(IrpContext, Vcb, FatIndex);
|
||
|
||
//
|
||
// Case on 12 or 16 bit fats.
|
||
//
|
||
// In the 12 bit case (mostly floppies) we always have the whole fat
|
||
// (max 6k bytes) pinned during allocation operations. This is possibly
|
||
// a wee bit slower, but saves headaches over fat entries with 8 bits
|
||
// on one page, and 4 bits on the next.
|
||
//
|
||
// The 16 bit case always keeps the last used page pinned until all
|
||
// operations are done and it is unpinned.
|
||
//
|
||
|
||
//
|
||
// DEAL WITH 12 BIT CASE
|
||
//
|
||
|
||
if (Vcb->AllocationSupport.FatIndexBitSize == 12) {
|
||
|
||
//
|
||
// Check to see if the fat is already pinned, otherwise pin it.
|
||
//
|
||
|
||
if (Context->Bcb == NULL) {
|
||
|
||
FatReadVolumeFile( IrpContext,
|
||
Vcb,
|
||
FatReservedBytes( &Vcb->Bpb ),
|
||
FatBytesPerFat( &Vcb->Bpb ),
|
||
&Context->Bcb,
|
||
&Context->PinnedPage );
|
||
}
|
||
|
||
//
|
||
// Load the return value.
|
||
//
|
||
|
||
|
||
FatLookup12BitEntry( Context->PinnedPage, FatIndex, FatEntry );
|
||
|
||
} else if (Vcb->AllocationSupport.FatIndexBitSize == 32) {
|
||
|
||
//
|
||
// DEAL WITH 32 BIT CASE
|
||
//
|
||
|
||
ULONG PageEntryOffset;
|
||
ULONG OffsetIntoVolumeFile;
|
||
|
||
//
|
||
// Initialize two local variables that help us.
|
||
//
|
||
OffsetIntoVolumeFile = FatReservedBytes(&Vcb->Bpb) + FatIndex * sizeof(FAT_ENTRY);
|
||
PageEntryOffset = (OffsetIntoVolumeFile % PAGE_SIZE) / sizeof(FAT_ENTRY);
|
||
|
||
//
|
||
// Check to see if we need to read in a new page of fat
|
||
//
|
||
|
||
if ((Context->Bcb == NULL) ||
|
||
(OffsetIntoVolumeFile / PAGE_SIZE != Context->VboOfPinnedPage / PAGE_SIZE)) {
|
||
|
||
//
|
||
// The entry wasn't in the pinned page, so must we unpin the current
|
||
// page (if any) and read in a new page.
|
||
//
|
||
|
||
FatUnpinBcb( IrpContext, Context->Bcb );
|
||
|
||
FatReadVolumeFile( IrpContext,
|
||
Vcb,
|
||
OffsetIntoVolumeFile & ~(PAGE_SIZE - 1),
|
||
PAGE_SIZE,
|
||
&Context->Bcb,
|
||
&Context->PinnedPage );
|
||
|
||
Context->VboOfPinnedPage = OffsetIntoVolumeFile & ~(PAGE_SIZE - 1);
|
||
}
|
||
|
||
//
|
||
// Grab the fat entry from the pinned page, and return
|
||
//
|
||
|
||
*FatEntry = ((PULONG)(Context->PinnedPage))[PageEntryOffset] & FAT32_ENTRY_MASK;
|
||
|
||
} else {
|
||
|
||
//
|
||
// DEAL WITH 16 BIT CASE
|
||
//
|
||
|
||
ULONG PageEntryOffset;
|
||
ULONG OffsetIntoVolumeFile;
|
||
|
||
//
|
||
// Initialize two local variables that help us.
|
||
//
|
||
|
||
OffsetIntoVolumeFile = FatReservedBytes(&Vcb->Bpb) + FatIndex * sizeof(USHORT);
|
||
PageEntryOffset = (OffsetIntoVolumeFile % PAGE_SIZE) / sizeof(USHORT);
|
||
|
||
//
|
||
// Check to see if we need to read in a new page of fat
|
||
//
|
||
|
||
if ((Context->Bcb == NULL) ||
|
||
(OffsetIntoVolumeFile / PAGE_SIZE != Context->VboOfPinnedPage / PAGE_SIZE)) {
|
||
|
||
//
|
||
// The entry wasn't in the pinned page, so must we unpin the current
|
||
// page (if any) and read in a new page.
|
||
//
|
||
|
||
FatUnpinBcb( IrpContext, Context->Bcb );
|
||
|
||
FatReadVolumeFile( IrpContext,
|
||
Vcb,
|
||
OffsetIntoVolumeFile & ~(PAGE_SIZE - 1),
|
||
PAGE_SIZE,
|
||
&Context->Bcb,
|
||
&Context->PinnedPage );
|
||
|
||
Context->VboOfPinnedPage = OffsetIntoVolumeFile & ~(PAGE_SIZE - 1);
|
||
}
|
||
|
||
//
|
||
// Grab the fat entry from the pinned page, and return
|
||
//
|
||
|
||
*FatEntry = ((PUSHORT)(Context->PinnedPage))[PageEntryOffset];
|
||
}
|
||
|
||
DebugTrace(-1, Dbg, "FatLookupFatEntry -> (VOID)\n", 0);
|
||
return;
|
||
}
|
||
|
||
|
||
_Requires_lock_held_(_Global_critical_region_)
|
||
VOID
|
||
FatSetFatEntry (
|
||
IN PIRP_CONTEXT IrpContext,
|
||
IN PVCB Vcb,
|
||
IN ULONG FatIndex,
|
||
IN FAT_ENTRY FatEntry
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine takes an index into the fat and puts a value in the Fat
|
||
at this index. The routine special cases 12, 16 and 32 bit fats. In
|
||
all cases we go to the cache manager for a piece of the fat.
|
||
|
||
We have a special form of this call for setting the DOS-style dirty bit.
|
||
Unlike the dirty bit in the boot sector, we do not go to special effort
|
||
to make sure that this hits the disk synchronously - if the system goes
|
||
down in the window between the dirty bit being set in the boot sector
|
||
and the FAT index zero dirty bit being lazy written, then life is tough.
|
||
|
||
The only possible scenario is that Win9x may see what it thinks is a clean
|
||
volume that really isn't (hopefully Memphis will pay attention to our dirty
|
||
bit as well). The dirty bit will get out quickly, and if heavy activity is
|
||
occurring, then the dirty bit should actually be there virtually all of the
|
||
time since the act of cleaning the volume is the "rare" occurance.
|
||
|
||
There are synchronization concerns that would crop up if we tried to make
|
||
this synchronous. This thread may already own the Bcb shared for the first
|
||
sector of the FAT (so we can't get it exclusive for a writethrough). This
|
||
would require some more serious replumbing to work around than I want to
|
||
consider at this time.
|
||
|
||
We can and do, however, synchronously set the bit clean.
|
||
|
||
At this point the reader should understand why the NT dirty bit is where it is.
|
||
|
||
Arguments:
|
||
|
||
Vcb - Supplies the Vcb to examine, yields 12/16/32 bit info, etc.
|
||
|
||
FatIndex - Supplies the destination fat index.
|
||
|
||
FatEntry - Supplies the source fat entry.
|
||
|
||
--*/
|
||
|
||
{
|
||
LBO Lbo;
|
||
PBCB Bcb = NULL;
|
||
ULONG SectorSize;
|
||
ULONG OffsetIntoVolumeFile;
|
||
ULONG WasWait = TRUE;
|
||
BOOLEAN RegularOperation = TRUE;
|
||
BOOLEAN CleaningOperation = FALSE;
|
||
BOOLEAN ReleaseMutex = FALSE;
|
||
|
||
PAGED_CODE();
|
||
|
||
DebugTrace(+1, Dbg, "FatSetFatEntry\n", 0);
|
||
DebugTrace( 0, Dbg, " Vcb = %p\n", Vcb);
|
||
DebugTrace( 0, Dbg, " FatIndex = %4x\n", FatIndex);
|
||
DebugTrace( 0, Dbg, " FatEntry = %4x\n", FatEntry);
|
||
|
||
//
|
||
// Make sure they gave us a valid fat index if this isn't the special
|
||
// clean-bit modifying call.
|
||
//
|
||
|
||
if (FatIndex == FAT_DIRTY_BIT_INDEX) {
|
||
|
||
//
|
||
// We are setting the clean bit state. Of course, we could
|
||
// have corruption that would cause us to try to fiddle the
|
||
// reserved index - we guard against this by having the
|
||
// special entry values use the reserved high 4 bits that
|
||
// we know that we'll never try to set.
|
||
//
|
||
|
||
//
|
||
// We don't want to repin the FAT pages involved here. Just
|
||
// let the lazy writer hit them when it can.
|
||
//
|
||
|
||
RegularOperation = FALSE;
|
||
|
||
switch (FatEntry) {
|
||
case FAT_CLEAN_VOLUME:
|
||
FatEntry = (FAT_ENTRY)FAT_CLEAN_ENTRY;
|
||
CleaningOperation = TRUE;
|
||
break;
|
||
|
||
case FAT_DIRTY_VOLUME:
|
||
switch (Vcb->AllocationSupport.FatIndexBitSize) {
|
||
case 12:
|
||
FatEntry = FAT12_DIRTY_ENTRY;
|
||
break;
|
||
|
||
case 32:
|
||
FatEntry = FAT32_DIRTY_ENTRY;
|
||
break;
|
||
|
||
default:
|
||
FatEntry = FAT16_DIRTY_ENTRY;
|
||
break;
|
||
}
|
||
break;
|
||
|
||
default:
|
||
FatRaiseStatus( IrpContext, STATUS_FILE_CORRUPT_ERROR );
|
||
break;
|
||
}
|
||
|
||
//
|
||
// Disable dirtying semantics for the duration of this operation. Force this
|
||
// operation to wait for the duration.
|
||
//
|
||
|
||
WasWait = FlagOn( IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT );
|
||
SetFlag( IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT | IRP_CONTEXT_FLAG_DISABLE_DIRTY );
|
||
|
||
} else {
|
||
|
||
NT_ASSERT( !(FatEntry & ~FAT32_ENTRY_MASK) );
|
||
FatVerifyIndexIsValid(IrpContext, Vcb, FatIndex);
|
||
}
|
||
|
||
//
|
||
// Set Sector Size
|
||
//
|
||
|
||
SectorSize = 1 << Vcb->AllocationSupport.LogOfBytesPerSector;
|
||
|
||
//
|
||
// Case on 12 or 16 bit fats.
|
||
//
|
||
// In the 12 bit case (mostly floppies) we always have the whole fat
|
||
// (max 6k bytes) pinned during allocation operations. This is possibly
|
||
// a wee bit slower, but saves headaches over fat entries with 8 bits
|
||
// on one page, and 4 bits on the next.
|
||
//
|
||
// In the 16 bit case we only read the page that we need to set the fat
|
||
// entry.
|
||
//
|
||
|
||
//
|
||
// DEAL WITH 12 BIT CASE
|
||
//
|
||
|
||
_SEH2_TRY {
|
||
|
||
if (Vcb->AllocationSupport.FatIndexBitSize == 12) {
|
||
|
||
PVOID PinnedFat;
|
||
|
||
//
|
||
// Make sure we have a valid entry
|
||
//
|
||
|
||
FatEntry &= 0xfff;
|
||
|
||
//
|
||
// We read in the entire fat. Note that using prepare write marks
|
||
// the bcb pre-dirty, so we don't have to do it explicitly.
|
||
//
|
||
|
||
OffsetIntoVolumeFile = FatReservedBytes( &Vcb->Bpb ) + FatIndex * 3 / 2;
|
||
|
||
FatPrepareWriteVolumeFile( IrpContext,
|
||
Vcb,
|
||
FatReservedBytes( &Vcb->Bpb ),
|
||
FatBytesPerFat( &Vcb->Bpb ),
|
||
&Bcb,
|
||
&PinnedFat,
|
||
RegularOperation,
|
||
FALSE );
|
||
|
||
//
|
||
// Mark the sector(s) dirty in the DirtyFatMcb. This call is
|
||
// complicated somewhat for the 12 bit case since a single
|
||
// entry write can span two sectors (and pages).
|
||
//
|
||
// Get the Lbo for the sector where the entry starts, and add it to
|
||
// the dirty fat Mcb.
|
||
//
|
||
|
||
Lbo = OffsetIntoVolumeFile & ~(SectorSize - 1);
|
||
|
||
FatAddMcbEntry( Vcb, &Vcb->DirtyFatMcb, (VBO) Lbo, Lbo, SectorSize);
|
||
|
||
//
|
||
// If the entry started on the last byte of the sector, it continues
|
||
// to the next sector, so mark the next sector dirty as well.
|
||
//
|
||
// Note that this entry will simply coalese with the last entry,
|
||
// so this operation cannot fail. Also if we get this far, we have
|
||
// made it, so no unwinding will be needed.
|
||
//
|
||
|
||
if ( (OffsetIntoVolumeFile & (SectorSize - 1)) == (SectorSize - 1) ) {
|
||
|
||
Lbo += SectorSize;
|
||
|
||
FatAddMcbEntry( Vcb, &Vcb->DirtyFatMcb, (VBO) Lbo, Lbo, SectorSize );
|
||
}
|
||
|
||
//
|
||
// Store the entry into the fat; we need a little synchonization
|
||
// here and can't use a spinlock since the bytes might not be
|
||
// resident.
|
||
//
|
||
|
||
FatLockFreeClusterBitMap( Vcb );
|
||
ReleaseMutex = TRUE;
|
||
|
||
FatSet12BitEntry( PinnedFat, FatIndex, FatEntry );
|
||
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
ReleaseMutex = FALSE;
|
||
|
||
} else if (Vcb->AllocationSupport.FatIndexBitSize == 32) {
|
||
|
||
//
|
||
// DEAL WITH 32 BIT CASE
|
||
//
|
||
|
||
PULONG PinnedFatEntry32;
|
||
|
||
//
|
||
// Read in a new page of fat
|
||
//
|
||
|
||
OffsetIntoVolumeFile = FatReservedBytes( &Vcb->Bpb ) +
|
||
FatIndex * sizeof( FAT_ENTRY );
|
||
|
||
FatPrepareWriteVolumeFile( IrpContext,
|
||
Vcb,
|
||
OffsetIntoVolumeFile,
|
||
sizeof(FAT_ENTRY),
|
||
&Bcb,
|
||
(PVOID *)&PinnedFatEntry32,
|
||
RegularOperation,
|
||
FALSE );
|
||
//
|
||
// Mark the sector dirty in the DirtyFatMcb
|
||
//
|
||
|
||
Lbo = OffsetIntoVolumeFile & ~(SectorSize - 1);
|
||
|
||
FatAddMcbEntry( Vcb, &Vcb->DirtyFatMcb, (VBO) Lbo, Lbo, SectorSize);
|
||
|
||
//
|
||
// Store the FatEntry to the pinned page.
|
||
//
|
||
// Preserve the reserved bits in FAT32 entries in the file heap.
|
||
//
|
||
|
||
#ifdef ALPHA
|
||
FatLockFreeClusterBitMap( Vcb );
|
||
ReleaseMutex = TRUE;
|
||
#endif // ALPHA
|
||
|
||
if (FatIndex != FAT_DIRTY_BIT_INDEX) {
|
||
|
||
*PinnedFatEntry32 = ((*PinnedFatEntry32 & ~FAT32_ENTRY_MASK) | FatEntry);
|
||
|
||
} else {
|
||
|
||
*PinnedFatEntry32 = FatEntry;
|
||
}
|
||
|
||
#ifdef ALPHA
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
ReleaseMutex = FALSE;
|
||
#endif // ALPHA
|
||
|
||
} else {
|
||
|
||
//
|
||
// DEAL WITH 16 BIT CASE
|
||
//
|
||
|
||
PUSHORT PinnedFatEntry;
|
||
|
||
//
|
||
// Read in a new page of fat
|
||
//
|
||
|
||
OffsetIntoVolumeFile = FatReservedBytes( &Vcb->Bpb ) +
|
||
FatIndex * sizeof(USHORT);
|
||
|
||
FatPrepareWriteVolumeFile( IrpContext,
|
||
Vcb,
|
||
OffsetIntoVolumeFile,
|
||
sizeof(USHORT),
|
||
&Bcb,
|
||
(PVOID *)&PinnedFatEntry,
|
||
RegularOperation,
|
||
FALSE );
|
||
//
|
||
// Mark the sector dirty in the DirtyFatMcb
|
||
//
|
||
|
||
Lbo = OffsetIntoVolumeFile & ~(SectorSize - 1);
|
||
|
||
FatAddMcbEntry( Vcb, &Vcb->DirtyFatMcb, (VBO) Lbo, Lbo, SectorSize);
|
||
|
||
//
|
||
// Store the FatEntry to the pinned page.
|
||
//
|
||
// We need extra synchronization here for broken architectures
|
||
// like the ALPHA that don't support atomic 16 bit writes.
|
||
//
|
||
|
||
#ifdef ALPHA
|
||
FatLockFreeClusterBitMap( Vcb );
|
||
ReleaseMutex = TRUE;
|
||
#endif // ALPHA
|
||
|
||
*PinnedFatEntry = (USHORT)FatEntry;
|
||
|
||
#ifdef ALPHA
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
ReleaseMutex = FALSE;
|
||
#endif // ALPHA
|
||
}
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
DebugUnwind( FatSetFatEntry );
|
||
|
||
//
|
||
// Re-enable volume dirtying in case this was a dirty bit operation.
|
||
//
|
||
|
||
ClearFlag( IrpContext->Flags, IRP_CONTEXT_FLAG_DISABLE_DIRTY );
|
||
|
||
//
|
||
// Make this operation asynchronous again if needed.
|
||
//
|
||
|
||
if (!WasWait) {
|
||
|
||
ClearFlag( IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT );
|
||
}
|
||
|
||
//
|
||
// If we still somehow have the Mutex, release it.
|
||
//
|
||
|
||
if (ReleaseMutex) {
|
||
|
||
NT_ASSERT( _SEH2_AbnormalTermination() );
|
||
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
}
|
||
|
||
//
|
||
// Unpin the Bcb. For cleaning operations or if the corruption was detected while mounting we make this write-through.
|
||
//
|
||
|
||
if ((CleaningOperation ||
|
||
FlagOn(Vcb->VcbState, VCB_STATE_FLAG_MOUNT_IN_PROGRESS)) &&
|
||
Bcb) {
|
||
|
||
IO_STATUS_BLOCK IgnoreStatus;
|
||
|
||
CcRepinBcb( Bcb );
|
||
CcUnpinData( Bcb );
|
||
DbgDoit( IrpContext->PinCount -= 1 );
|
||
CcUnpinRepinnedBcb( Bcb, TRUE, &IgnoreStatus );
|
||
|
||
} else {
|
||
|
||
FatUnpinBcb(IrpContext, Bcb);
|
||
}
|
||
|
||
DebugTrace(-1, Dbg, "FatSetFatEntry -> (VOID)\n", 0);
|
||
} _SEH2_END;
|
||
|
||
return;
|
||
}
|
||
|
||
|
||
//
|
||
// Internal support routine
|
||
//
|
||
|
||
VOID
|
||
FatSetFatRun (
|
||
IN PIRP_CONTEXT IrpContext,
|
||
IN PVCB Vcb,
|
||
IN ULONG StartingFatIndex,
|
||
IN ULONG ClusterCount,
|
||
IN BOOLEAN ChainTogether
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine sets a continuous run of clusters in the fat. If ChainTogether
|
||
is TRUE, then the clusters are linked together as in normal Fat fasion,
|
||
with the last cluster receiving FAT_CLUSTER_LAST. If ChainTogether is
|
||
FALSE, all the entries are set to FAT_CLUSTER_AVAILABLE, effectively
|
||
freeing all the clusters in the run.
|
||
|
||
Arguments:
|
||
|
||
Vcb - Supplies the Vcb to examine, yields 12/16 bit info, etc.
|
||
|
||
StartingFatIndex - Supplies the destination fat index.
|
||
|
||
ClusterCount - Supplies the number of contiguous clusters to work on.
|
||
|
||
ChainTogether - Tells us whether to fill the entries with links, or
|
||
FAT_CLUSTER_AVAILABLE
|
||
|
||
|
||
Return Value:
|
||
|
||
VOID
|
||
|
||
--*/
|
||
|
||
{
|
||
#define MAXCOUNTCLUS 0x10000
|
||
#define COUNTSAVEDBCBS ((MAXCOUNTCLUS * sizeof(FAT_ENTRY) / PAGE_SIZE) + 2)
|
||
PBCB SavedBcbs[COUNTSAVEDBCBS][2];
|
||
|
||
ULONG SectorSize;
|
||
ULONG Cluster;
|
||
|
||
LBO StartSectorLbo;
|
||
LBO FinalSectorLbo;
|
||
LBO Lbo;
|
||
|
||
PVOID PinnedFat;
|
||
|
||
BOOLEAN ReleaseMutex = FALSE;
|
||
|
||
ULONG SavedStartingFatIndex = StartingFatIndex;
|
||
|
||
PAGED_CODE();
|
||
|
||
DebugTrace(+1, Dbg, "FatSetFatRun\n", 0);
|
||
DebugTrace( 0, Dbg, " Vcb = %p\n", Vcb);
|
||
DebugTrace( 0, Dbg, " StartingFatIndex = %8x\n", StartingFatIndex);
|
||
DebugTrace( 0, Dbg, " ClusterCount = %8lx\n", ClusterCount);
|
||
DebugTrace( 0, Dbg, " ChainTogether = %s\n", ChainTogether ? "TRUE":"FALSE");
|
||
|
||
//
|
||
// Make sure they gave us a valid fat run.
|
||
//
|
||
|
||
FatVerifyIndexIsValid(IrpContext, Vcb, StartingFatIndex);
|
||
FatVerifyIndexIsValid(IrpContext, Vcb, StartingFatIndex + ClusterCount - 1);
|
||
|
||
//
|
||
// Check special case
|
||
//
|
||
|
||
if (ClusterCount == 0) {
|
||
|
||
DebugTrace(-1, Dbg, "FatSetFatRun -> (VOID)\n", 0);
|
||
return;
|
||
}
|
||
|
||
//
|
||
// Set Sector Size
|
||
//
|
||
|
||
SectorSize = 1 << Vcb->AllocationSupport.LogOfBytesPerSector;
|
||
|
||
//
|
||
// Case on 12 or 16 bit fats.
|
||
//
|
||
// In the 12 bit case (mostly floppies) we always have the whole fat
|
||
// (max 6k bytes) pinned during allocation operations. This is possibly
|
||
// a wee bit slower, but saves headaches over fat entries with 8 bits
|
||
// on one page, and 4 bits on the next.
|
||
//
|
||
// In the 16 bit case we only read one page at a time, as needed.
|
||
//
|
||
|
||
//
|
||
// DEAL WITH 12 BIT CASE
|
||
//
|
||
|
||
_SEH2_TRY {
|
||
|
||
if (Vcb->AllocationSupport.FatIndexBitSize == 12) {
|
||
|
||
//
|
||
// We read in the entire fat. Note that using prepare write marks
|
||
// the bcb pre-dirty, so we don't have to do it explicitly.
|
||
//
|
||
|
||
RtlZeroMemory( &SavedBcbs[0][0], 2 * sizeof(PBCB) * 2);
|
||
|
||
FatPrepareWriteVolumeFile( IrpContext,
|
||
Vcb,
|
||
FatReservedBytes( &Vcb->Bpb ),
|
||
FatBytesPerFat( &Vcb->Bpb ),
|
||
&SavedBcbs[0][0],
|
||
&PinnedFat,
|
||
TRUE,
|
||
FALSE );
|
||
|
||
//
|
||
// Mark the affected sectors dirty. Note that FinalSectorLbo is
|
||
// the Lbo of the END of the entry (Thus * 3 + 2). This makes sure
|
||
// we catch the case of a dirty fat entry straddling a sector boundry.
|
||
//
|
||
// Note that if the first AddMcbEntry succeeds, all following ones
|
||
// will simply coalese, and thus also succeed.
|
||
//
|
||
|
||
StartSectorLbo = (FatReservedBytes( &Vcb->Bpb ) + StartingFatIndex * 3 / 2)
|
||
& ~(SectorSize - 1);
|
||
|
||
FinalSectorLbo = (FatReservedBytes( &Vcb->Bpb ) + ((StartingFatIndex +
|
||
ClusterCount) * 3 + 2) / 2) & ~(SectorSize - 1);
|
||
|
||
for (Lbo = StartSectorLbo; Lbo <= FinalSectorLbo; Lbo += SectorSize) {
|
||
|
||
FatAddMcbEntry( Vcb, &Vcb->DirtyFatMcb, (VBO) Lbo, Lbo, SectorSize );
|
||
}
|
||
|
||
//
|
||
// Store the entries into the fat; we need a little
|
||
// synchonization here and can't use a spinlock since the bytes
|
||
// might not be resident.
|
||
//
|
||
|
||
FatLockFreeClusterBitMap( Vcb );
|
||
ReleaseMutex = TRUE;
|
||
|
||
for (Cluster = StartingFatIndex;
|
||
Cluster < StartingFatIndex + ClusterCount - 1;
|
||
Cluster++) {
|
||
|
||
FatSet12BitEntry( PinnedFat,
|
||
Cluster,
|
||
ChainTogether ? Cluster + 1 : FAT_CLUSTER_AVAILABLE );
|
||
}
|
||
|
||
//
|
||
// Save the last entry
|
||
//
|
||
|
||
FatSet12BitEntry( PinnedFat,
|
||
Cluster,
|
||
ChainTogether ?
|
||
FAT_CLUSTER_LAST & 0xfff : FAT_CLUSTER_AVAILABLE );
|
||
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
ReleaseMutex = FALSE;
|
||
|
||
} else if (Vcb->AllocationSupport.FatIndexBitSize == 32) {
|
||
|
||
//
|
||
// DEAL WITH 32 BIT CASE
|
||
//
|
||
|
||
for (;;) {
|
||
|
||
VBO StartOffsetInVolume;
|
||
VBO FinalOffsetInVolume;
|
||
|
||
ULONG Page;
|
||
ULONG FinalCluster;
|
||
PULONG FatEntry = NULL;
|
||
ULONG ClusterCountThisRun;
|
||
|
||
StartOffsetInVolume = FatReservedBytes(&Vcb->Bpb) +
|
||
StartingFatIndex * sizeof(FAT_ENTRY);
|
||
|
||
if (ClusterCount > MAXCOUNTCLUS) {
|
||
ClusterCountThisRun = MAXCOUNTCLUS;
|
||
} else {
|
||
ClusterCountThisRun = ClusterCount;
|
||
}
|
||
|
||
FinalOffsetInVolume = StartOffsetInVolume +
|
||
(ClusterCountThisRun - 1) * sizeof(FAT_ENTRY);
|
||
|
||
{
|
||
ULONG NumberOfPages;
|
||
ULONG Offset;
|
||
|
||
NumberOfPages = (FinalOffsetInVolume / PAGE_SIZE) -
|
||
(StartOffsetInVolume / PAGE_SIZE) + 1;
|
||
|
||
RtlZeroMemory( &SavedBcbs[0][0], (NumberOfPages + 1) * sizeof(PBCB) * 2 );
|
||
|
||
for ( Page = 0, Offset = StartOffsetInVolume & ~(PAGE_SIZE - 1);
|
||
Page < NumberOfPages;
|
||
Page++, Offset += PAGE_SIZE ) {
|
||
|
||
FatPrepareWriteVolumeFile( IrpContext,
|
||
Vcb,
|
||
Offset,
|
||
PAGE_SIZE,
|
||
&SavedBcbs[Page][0],
|
||
(PVOID *)&SavedBcbs[Page][1],
|
||
TRUE,
|
||
FALSE );
|
||
|
||
if (Page == 0) {
|
||
|
||
FatEntry = (PULONG)((PUCHAR)SavedBcbs[0][1] +
|
||
(StartOffsetInVolume % PAGE_SIZE));
|
||
}
|
||
}
|
||
}
|
||
|
||
//
|
||
// Mark the run dirty
|
||
//
|
||
|
||
StartSectorLbo = StartOffsetInVolume & ~(SectorSize - 1);
|
||
FinalSectorLbo = FinalOffsetInVolume & ~(SectorSize - 1);
|
||
|
||
for (Lbo = StartSectorLbo; Lbo <= FinalSectorLbo; Lbo += SectorSize) {
|
||
|
||
FatAddMcbEntry( Vcb, &Vcb->DirtyFatMcb, (VBO)Lbo, Lbo, SectorSize );
|
||
}
|
||
|
||
//
|
||
// Store the entries
|
||
//
|
||
// We need extra synchronization here for broken architectures
|
||
// like the ALPHA that don't support atomic 16 bit writes.
|
||
//
|
||
|
||
#ifdef ALPHA
|
||
FatLockFreeClusterBitMap( Vcb );
|
||
ReleaseMutex = TRUE;
|
||
#endif // ALPHA
|
||
|
||
FinalCluster = StartingFatIndex + ClusterCountThisRun - 1;
|
||
Page = 0;
|
||
|
||
for (Cluster = StartingFatIndex;
|
||
Cluster <= FinalCluster;
|
||
Cluster++, FatEntry++) {
|
||
|
||
//
|
||
// If we just crossed a page boundry (as opposed to starting
|
||
// on one), update our idea of FatEntry.
|
||
|
||
if ( (((ULONG_PTR)FatEntry & (PAGE_SIZE-1)) == 0) &&
|
||
(Cluster != StartingFatIndex) ) {
|
||
|
||
Page += 1;
|
||
FatEntry = (PULONG)SavedBcbs[Page][1];
|
||
}
|
||
|
||
*FatEntry = ChainTogether ? (FAT_ENTRY)(Cluster + 1) :
|
||
FAT_CLUSTER_AVAILABLE;
|
||
}
|
||
|
||
//
|
||
// Fix up the last entry if we were chaining together
|
||
//
|
||
|
||
if ((ClusterCount <= MAXCOUNTCLUS) &&
|
||
ChainTogether ) {
|
||
|
||
*(FatEntry-1) = FAT_CLUSTER_LAST;
|
||
}
|
||
|
||
#ifdef ALPHA
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
ReleaseMutex = FALSE;
|
||
#endif // ALPHA
|
||
|
||
{
|
||
ULONG i;
|
||
|
||
//
|
||
// Unpin the Bcbs
|
||
//
|
||
|
||
for (i = 0; (i < COUNTSAVEDBCBS) && (SavedBcbs[i][0] != NULL); i++) {
|
||
|
||
FatUnpinBcb( IrpContext, SavedBcbs[i][0] );
|
||
SavedBcbs[i][0] = NULL;
|
||
}
|
||
}
|
||
|
||
if (ClusterCount <= MAXCOUNTCLUS) {
|
||
|
||
break;
|
||
|
||
} else {
|
||
|
||
StartingFatIndex += MAXCOUNTCLUS;
|
||
ClusterCount -= MAXCOUNTCLUS;
|
||
}
|
||
}
|
||
|
||
} else {
|
||
|
||
//
|
||
// DEAL WITH 16 BIT CASE
|
||
//
|
||
|
||
VBO StartOffsetInVolume;
|
||
VBO FinalOffsetInVolume;
|
||
|
||
ULONG Page;
|
||
ULONG FinalCluster;
|
||
PUSHORT FatEntry = NULL;
|
||
|
||
StartOffsetInVolume = FatReservedBytes(&Vcb->Bpb) +
|
||
StartingFatIndex * sizeof(USHORT);
|
||
|
||
FinalOffsetInVolume = StartOffsetInVolume +
|
||
(ClusterCount - 1) * sizeof(USHORT);
|
||
|
||
//
|
||
// Read in one page of fat at a time. We cannot read in the
|
||
// all of the fat we need because of cache manager limitations.
|
||
//
|
||
// SavedBcb was initialized to be able to hold the largest
|
||
// possible number of pages in a fat plus and extra one to
|
||
// accomadate the boot sector, plus one more to make sure there
|
||
// is enough room for the RtlZeroMemory below that needs the mark
|
||
// the first Bcb after all the ones we will use as an end marker.
|
||
//
|
||
|
||
{
|
||
ULONG NumberOfPages;
|
||
ULONG Offset;
|
||
|
||
NumberOfPages = (FinalOffsetInVolume / PAGE_SIZE) -
|
||
(StartOffsetInVolume / PAGE_SIZE) + 1;
|
||
|
||
RtlZeroMemory( &SavedBcbs[0][0], (NumberOfPages + 1) * sizeof(PBCB) * 2 );
|
||
|
||
for ( Page = 0, Offset = StartOffsetInVolume & ~(PAGE_SIZE - 1);
|
||
Page < NumberOfPages;
|
||
Page++, Offset += PAGE_SIZE ) {
|
||
|
||
FatPrepareWriteVolumeFile( IrpContext,
|
||
Vcb,
|
||
Offset,
|
||
PAGE_SIZE,
|
||
&SavedBcbs[Page][0],
|
||
(PVOID *)&SavedBcbs[Page][1],
|
||
TRUE,
|
||
FALSE );
|
||
|
||
if (Page == 0) {
|
||
|
||
FatEntry = (PUSHORT)((PUCHAR)SavedBcbs[0][1] +
|
||
(StartOffsetInVolume % PAGE_SIZE));
|
||
}
|
||
}
|
||
}
|
||
|
||
//
|
||
// Mark the run dirty
|
||
//
|
||
|
||
StartSectorLbo = StartOffsetInVolume & ~(SectorSize - 1);
|
||
FinalSectorLbo = FinalOffsetInVolume & ~(SectorSize - 1);
|
||
|
||
for (Lbo = StartSectorLbo; Lbo <= FinalSectorLbo; Lbo += SectorSize) {
|
||
|
||
FatAddMcbEntry( Vcb, &Vcb->DirtyFatMcb, (VBO) Lbo, Lbo, SectorSize );
|
||
}
|
||
|
||
//
|
||
// Store the entries
|
||
//
|
||
// We need extra synchronization here for broken architectures
|
||
// like the ALPHA that don't support atomic 16 bit writes.
|
||
//
|
||
|
||
#ifdef ALPHA
|
||
FatLockFreeClusterBitMap( Vcb );
|
||
ReleaseMutex = TRUE;
|
||
#endif // ALPHA
|
||
|
||
FinalCluster = StartingFatIndex + ClusterCount - 1;
|
||
Page = 0;
|
||
|
||
for (Cluster = StartingFatIndex;
|
||
Cluster <= FinalCluster;
|
||
Cluster++, FatEntry++) {
|
||
|
||
//
|
||
// If we just crossed a page boundry (as opposed to starting
|
||
// on one), update our idea of FatEntry.
|
||
|
||
if ( (((ULONG_PTR)FatEntry & (PAGE_SIZE-1)) == 0) &&
|
||
(Cluster != StartingFatIndex) ) {
|
||
|
||
Page += 1;
|
||
FatEntry = (PUSHORT)SavedBcbs[Page][1];
|
||
}
|
||
|
||
*FatEntry = (USHORT) (ChainTogether ? (FAT_ENTRY)(Cluster + 1) :
|
||
FAT_CLUSTER_AVAILABLE);
|
||
}
|
||
|
||
//
|
||
// Fix up the last entry if we were chaining together
|
||
//
|
||
|
||
if ( ChainTogether ) {
|
||
|
||
#ifdef _MSC_VER
|
||
#pragma warning( suppress: 4310 )
|
||
#endif
|
||
*(FatEntry-1) = (USHORT)FAT_CLUSTER_LAST;
|
||
|
||
}
|
||
#ifdef ALPHA
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
ReleaseMutex = FALSE;
|
||
#endif // ALPHA
|
||
}
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
ULONG i;
|
||
|
||
DebugUnwind( FatSetFatRun );
|
||
|
||
//
|
||
// If we still somehow have the Mutex, release it.
|
||
//
|
||
|
||
if (ReleaseMutex) {
|
||
|
||
NT_ASSERT( _SEH2_AbnormalTermination() );
|
||
|
||
FatUnlockFreeClusterBitMap( Vcb );
|
||
}
|
||
|
||
//
|
||
// Unpin the Bcbs
|
||
//
|
||
|
||
for (i = 0; (i < COUNTSAVEDBCBS) && (SavedBcbs[i][0] != NULL); i++) {
|
||
|
||
FatUnpinBcb( IrpContext, SavedBcbs[i][0] );
|
||
}
|
||
|
||
//
|
||
// At this point nothing in this finally clause should have raised.
|
||
// So, now comes the unsafe (sigh) stuff.
|
||
//
|
||
|
||
if ( _SEH2_AbnormalTermination() &&
|
||
(Vcb->AllocationSupport.FatIndexBitSize == 32) ) {
|
||
|
||
//
|
||
// Fat32 unwind
|
||
//
|
||
// This case is more complex because the FAT12 and FAT16 cases
|
||
// pin all the needed FAT pages (128K max), after which it
|
||
// can't fail, before changing any FAT entries. In the Fat32
|
||
// case, it may not be practical to pin all the needed FAT
|
||
// pages, because that could span many megabytes. So Fat32
|
||
// attacks in chunks, and if a failure occurs once the first
|
||
// chunk has been updated, we have to back out the updates.
|
||
//
|
||
// The unwind consists of walking back over each FAT entry we
|
||
// have changed, setting it back to the previous value. Note
|
||
// that the previous value with either be FAT_CLUSTER_AVAILABLE
|
||
// (if ChainTogether==TRUE) or a simple link to the successor
|
||
// (if ChainTogether==FALSE).
|
||
//
|
||
// We concede that any one of these calls could fail too; our
|
||
// objective is to make this case no more likely than the case
|
||
// for a file consisting of multiple disjoint runs.
|
||
//
|
||
|
||
while ( StartingFatIndex > SavedStartingFatIndex ) {
|
||
|
||
StartingFatIndex--;
|
||
|
||
FatSetFatEntry( IrpContext, Vcb, StartingFatIndex,
|
||
ChainTogether ?
|
||
StartingFatIndex + 1 : FAT_CLUSTER_AVAILABLE );
|
||
}
|
||
}
|
||
|
||
DebugTrace(-1, Dbg, "FatSetFatRun -> (VOID)\n", 0);
|
||
} _SEH2_END;
|
||
|
||
return;
|
||
}
|
||
|
||
|
||
//
|
||
// Internal support routine
|
||
//
|
||
|
||
UCHAR
|
||
FatLogOf (
|
||
IN ULONG Value
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine just computes the base 2 log of an integer. It is only used
|
||
on objects that are know to be powers of two.
|
||
|
||
Arguments:
|
||
|
||
Value - The value to take the base 2 log of.
|
||
|
||
Return Value:
|
||
|
||
UCHAR - The base 2 log of Value.
|
||
|
||
--*/
|
||
|
||
{
|
||
UCHAR Log = 0;
|
||
|
||
#if FASTFATDBG
|
||
ULONG OrigValue = Value;
|
||
#endif
|
||
|
||
PAGED_CODE();
|
||
|
||
//
|
||
// Knock bits off until we we get a one at position 0
|
||
//
|
||
|
||
while ( (Value & 0xfffffffe) != 0 ) {
|
||
|
||
Log++;
|
||
Value >>= 1;
|
||
}
|
||
|
||
//
|
||
// If there was more than one bit set, the file system messed up,
|
||
// Bug Check.
|
||
//
|
||
|
||
if (Value != 0x1) {
|
||
|
||
DebugTrace(+1, Dbg, "LogOf\n", 0);
|
||
DebugTrace( 0, Dbg, " Value = %8lx\n", OrigValue);
|
||
|
||
DebugTrace( 0, Dbg, "Received non power of 2.\n", 0);
|
||
|
||
DebugTrace(-1, Dbg, "LogOf -> %8lx\n", Log);
|
||
|
||
#ifdef _MSC_VER
|
||
#pragma prefast( suppress: 28159, "we bugcheck here because our internal data structures are seriously corrupted if this happens" )
|
||
#endif
|
||
FatBugCheck( Value, Log, 0 );
|
||
}
|
||
|
||
return Log;
|
||
}
|
||
|
||
|
||
VOID
|
||
FatExamineFatEntries(
|
||
IN PIRP_CONTEXT IrpContext,
|
||
IN PVCB Vcb,
|
||
IN ULONG StartIndex OPTIONAL,
|
||
IN ULONG EndIndex OPTIONAL,
|
||
IN BOOLEAN SetupWindows,
|
||
IN PFAT_WINDOW SwitchToWindow OPTIONAL,
|
||
IN PULONG BitMapBuffer OPTIONAL
|
||
)
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine handles scanning a segment of the FAT into in-memory structures.
|
||
|
||
There are three fundamental cases, with variations depending on the FAT type:
|
||
|
||
1) During volume setup, FatSetupAllocations
|
||
|
||
1a) for FAT12/16, read the FAT into our free clusterbitmap
|
||
1b) for FAT32, perform the initial scan for window free cluster counts
|
||
|
||
2) Switching FAT32 windows on the fly during system operation
|
||
|
||
3) Reading arbitrary segments of the FAT for the purposes of the GetVolumeBitmap
|
||
call (only for FAT32)
|
||
|
||
There really is too much going on in here. At some point this should be
|
||
substantially rewritten.
|
||
|
||
Arguments:
|
||
|
||
Vcb - Supplies the volume involved
|
||
|
||
StartIndex - Supplies the starting cluster, ignored if SwitchToWindow supplied
|
||
|
||
EndIndex - Supplies the ending cluster, ignored if SwitchToWindow supplied
|
||
|
||
SetupWindows - Indicates if we are doing the initial FAT32 scan
|
||
|
||
SwitchToWindow - Supplies the FAT window we are examining and will switch to
|
||
|
||
BitMapBuffer - Supplies a specific bitmap to fill in, if not supplied we fill
|
||
in the volume free cluster bitmap if !SetupWindows
|
||
|
||
Return Value:
|
||
|
||
None. Lots of side effects.
|
||
|
||
--*/
|
||
{
|
||
ULONG FatIndexBitSize;
|
||
ULONG Page = 0;
|
||
ULONG Offset = 0;
|
||
ULONG FatIndex;
|
||
FAT_ENTRY FatEntry = FAT_CLUSTER_AVAILABLE;
|
||
FAT_ENTRY FirstFatEntry = FAT_CLUSTER_AVAILABLE;
|
||
PUSHORT FatBuffer;
|
||
PVOID pv;
|
||
PBCB Bcb = NULL;
|
||
ULONG EntriesPerWindow;
|
||
|
||
ULONG ClustersThisRun;
|
||
ULONG StartIndexOfThisRun;
|
||
|
||
PULONG FreeClusterCount = NULL;
|
||
|
||
PFAT_WINDOW CurrentWindow = NULL;
|
||
|
||
PVOID NewBitMapBuffer = NULL;
|
||
PRTL_BITMAP BitMap = NULL;
|
||
RTL_BITMAP PrivateBitMap;
|
||
|
||
ULONG ClusterSize = 0;
|
||
ULONG PrefetchPages = 0;
|
||
ULONG FatPages = 0;
|
||
|
||
VBO BadClusterVbo = 0;
|
||
LBO Lbo = 0;
|
||
|
||
enum RunType {
|
||
FreeClusters,
|
||
AllocatedClusters,
|
||
UnknownClusters
|
||
} CurrentRun;
|
||
|
||
PAGED_CODE();
|
||
|
||
//
|
||
// Now assert correct usage.
|
||
//
|
||
|
||
FatIndexBitSize = Vcb->AllocationSupport.FatIndexBitSize;
|
||
|
||
NT_ASSERT( !(SetupWindows && (SwitchToWindow || BitMapBuffer)));
|
||
NT_ASSERT( !(SetupWindows && FatIndexBitSize != 32));
|
||
|
||
if (Vcb->NumberOfWindows > 1) {
|
||
|
||
//
|
||
// FAT32: Calculate the number of FAT entries covered by a window. This is
|
||
// equal to the number of bits in the freespace bitmap, the size of which
|
||
// is hardcoded.
|
||
//
|
||
|
||
EntriesPerWindow = MAX_CLUSTER_BITMAP_SIZE;
|
||
|
||
} else {
|
||
|
||
EntriesPerWindow = Vcb->AllocationSupport.NumberOfClusters;
|
||
}
|
||
|
||
//
|
||
// We will also fill in the cumulative count of free clusters for
|
||
// the entire volume. If this is not appropriate, NULL it out
|
||
// shortly.
|
||
//
|
||
|
||
FreeClusterCount = &Vcb->AllocationSupport.NumberOfFreeClusters;
|
||
|
||
if (SetupWindows) {
|
||
|
||
NT_ASSERT(BitMapBuffer == NULL);
|
||
|
||
//
|
||
// In this case we're just supposed to scan the fat and set up
|
||
// the information regarding where the buckets fall and how many
|
||
// free clusters are in each.
|
||
//
|
||
// It is fine to monkey with the real windows, we must be able
|
||
// to do this to activate the volume.
|
||
//
|
||
|
||
BitMap = NULL;
|
||
|
||
CurrentWindow = &Vcb->Windows[0];
|
||
CurrentWindow->FirstCluster = StartIndex;
|
||
CurrentWindow->ClustersFree = 0;
|
||
|
||
//
|
||
// We always wish to calculate total free clusters when
|
||
// setting up the FAT windows.
|
||
//
|
||
|
||
} else if (BitMapBuffer == NULL) {
|
||
|
||
//
|
||
// We will be filling in the free cluster bitmap for the volume.
|
||
// Careful, we can raise out of here and be hopelessly hosed if
|
||
// we built this up in the main bitmap/window itself.
|
||
//
|
||
// For simplicity's sake, we'll do the swap for everyone. FAT32
|
||
// provokes the need since we can't tolerate partial results
|
||
// when switching windows.
|
||
//
|
||
|
||
NT_ASSERT( SwitchToWindow );
|
||
|
||
CurrentWindow = SwitchToWindow;
|
||
StartIndex = CurrentWindow->FirstCluster;
|
||
EndIndex = CurrentWindow->LastCluster;
|
||
|
||
BitMap = &PrivateBitMap;
|
||
NewBitMapBuffer = FsRtlAllocatePoolWithTag( PagedPool,
|
||
(EntriesPerWindow + 7) / 8,
|
||
TAG_FAT_BITMAP );
|
||
|
||
RtlInitializeBitMap( &PrivateBitMap,
|
||
NewBitMapBuffer,
|
||
EndIndex - StartIndex + 1);
|
||
|
||
if ((FatIndexBitSize == 32) &&
|
||
(Vcb->NumberOfWindows > 1)) {
|
||
|
||
//
|
||
// We do not wish count total clusters here.
|
||
//
|
||
|
||
FreeClusterCount = NULL;
|
||
|
||
}
|
||
|
||
} else {
|
||
|
||
BitMap = &PrivateBitMap;
|
||
RtlInitializeBitMap(&PrivateBitMap,
|
||
BitMapBuffer,
|
||
EndIndex - StartIndex + 1);
|
||
|
||
//
|
||
// We do not count total clusters here.
|
||
//
|
||
|
||
FreeClusterCount = NULL;
|
||
}
|
||
|
||
//
|
||
// Now, our start index better be in the file heap.
|
||
//
|
||
|
||
NT_ASSERT( StartIndex >= 2 );
|
||
|
||
_SEH2_TRY {
|
||
|
||
//
|
||
// Pick up the initial chunk of the FAT and first entry.
|
||
//
|
||
|
||
if (FatIndexBitSize == 12) {
|
||
|
||
//
|
||
// We read in the entire fat in the 12 bit case.
|
||
//
|
||
|
||
FatReadVolumeFile( IrpContext,
|
||
Vcb,
|
||
FatReservedBytes( &Vcb->Bpb ),
|
||
FatBytesPerFat( &Vcb->Bpb ),
|
||
&Bcb,
|
||
(PVOID *)&FatBuffer );
|
||
|
||
FatLookup12BitEntry(FatBuffer, 0, &FirstFatEntry);
|
||
|
||
} else {
|
||
|
||
//
|
||
// Read in one page of fat at a time. We cannot read in the
|
||
// all of the fat we need because of cache manager limitations.
|
||
//
|
||
|
||
ULONG BytesPerEntry = FatIndexBitSize >> 3;
|
||
|
||
FatPages = (FatReservedBytes(&Vcb->Bpb) + FatBytesPerFat(&Vcb->Bpb) + (PAGE_SIZE - 1)) / PAGE_SIZE;
|
||
Page = (FatReservedBytes(&Vcb->Bpb) + StartIndex * BytesPerEntry) / PAGE_SIZE;
|
||
|
||
Offset = Page * PAGE_SIZE;
|
||
|
||
//
|
||
// Prefetch the FAT entries in memory for optimal performance.
|
||
//
|
||
|
||
PrefetchPages = FatPages - Page;
|
||
|
||
if (PrefetchPages > FAT_PREFETCH_PAGE_COUNT) {
|
||
|
||
PrefetchPages = ALIGN_UP_BY(Page, FAT_PREFETCH_PAGE_COUNT) - Page;
|
||
}
|
||
|
||
#if (NTDDI_VERSION >= NTDDI_WIN8)
|
||
FatPrefetchPages( IrpContext,
|
||
Vcb->VirtualVolumeFile,
|
||
Page,
|
||
PrefetchPages );
|
||
#endif
|
||
|
||
FatReadVolumeFile( IrpContext,
|
||
Vcb,
|
||
Offset,
|
||
PAGE_SIZE,
|
||
&Bcb,
|
||
&pv);
|
||
|
||
if (FatIndexBitSize == 32) {
|
||
|
||
FatBuffer = (PUSHORT)((PUCHAR)pv +
|
||
(FatReservedBytes(&Vcb->Bpb) + StartIndex * BytesPerEntry) %
|
||
PAGE_SIZE);
|
||
|
||
FirstFatEntry = *((PULONG)FatBuffer);
|
||
FirstFatEntry = FirstFatEntry & FAT32_ENTRY_MASK;
|
||
|
||
} else {
|
||
|
||
FatBuffer = (PUSHORT)((PUCHAR)pv +
|
||
FatReservedBytes(&Vcb->Bpb) % PAGE_SIZE) + 2;
|
||
|
||
FirstFatEntry = *FatBuffer;
|
||
}
|
||
|
||
}
|
||
|
||
ClusterSize = 1 << (Vcb->AllocationSupport.LogOfBytesPerCluster);
|
||
|
||
CurrentRun = (FirstFatEntry == FAT_CLUSTER_AVAILABLE) ?
|
||
FreeClusters : AllocatedClusters;
|
||
|
||
StartIndexOfThisRun = StartIndex;
|
||
|
||
for (FatIndex = StartIndex; FatIndex <= EndIndex; FatIndex++) {
|
||
|
||
if (FatIndexBitSize == 12) {
|
||
|
||
FatLookup12BitEntry(FatBuffer, FatIndex, &FatEntry);
|
||
|
||
} else {
|
||
|
||
//
|
||
// If we are setting up the FAT32 windows and have stepped into a new
|
||
// bucket, finalize this one and move forward.
|
||
//
|
||
|
||
if (SetupWindows &&
|
||
FatIndex > StartIndex &&
|
||
(FatIndex - 2) % EntriesPerWindow == 0) {
|
||
|
||
CurrentWindow->LastCluster = FatIndex - 1;
|
||
|
||
if (CurrentRun == FreeClusters) {
|
||
|
||
//
|
||
// We must be counting clusters in order to modify the
|
||
// contents of the window.
|
||
//
|
||
|
||
NT_ASSERT( FreeClusterCount );
|
||
|
||
ClustersThisRun = FatIndex - StartIndexOfThisRun;
|
||
CurrentWindow->ClustersFree += ClustersThisRun;
|
||
|
||
if (FreeClusterCount) {
|
||
*FreeClusterCount += ClustersThisRun;
|
||
}
|
||
|
||
} else {
|
||
|
||
NT_ASSERT(CurrentRun == AllocatedClusters);
|
||
|
||
}
|
||
|
||
StartIndexOfThisRun = FatIndex;
|
||
CurrentRun = UnknownClusters;
|
||
|
||
CurrentWindow++;
|
||
CurrentWindow->ClustersFree = 0;
|
||
CurrentWindow->FirstCluster = FatIndex;
|
||
}
|
||
|
||
//
|
||
// If we just stepped onto a new page, grab a new pointer.
|
||
//
|
||
|
||
if (((ULONG_PTR)FatBuffer & (PAGE_SIZE - 1)) == 0) {
|
||
|
||
FatUnpinBcb( IrpContext, Bcb );
|
||
|
||
Page++;
|
||
Offset += PAGE_SIZE;
|
||
|
||
#if (NTDDI_VERSION >= NTDDI_WIN8)
|
||
//
|
||
// If we have exhausted all the prefetch pages, prefetch the next chunk.
|
||
//
|
||
|
||
if (--PrefetchPages == 0) {
|
||
|
||
PrefetchPages = FatPages - Page;
|
||
|
||
if (PrefetchPages > FAT_PREFETCH_PAGE_COUNT) {
|
||
|
||
PrefetchPages = FAT_PREFETCH_PAGE_COUNT;
|
||
}
|
||
|
||
FatPrefetchPages( IrpContext,
|
||
Vcb->VirtualVolumeFile,
|
||
Page,
|
||
PrefetchPages );
|
||
}
|
||
#endif
|
||
|
||
FatReadVolumeFile( IrpContext,
|
||
Vcb,
|
||
Offset,
|
||
PAGE_SIZE,
|
||
&Bcb,
|
||
&pv );
|
||
|
||
FatBuffer = (PUSHORT)pv;
|
||
}
|
||
|
||
if (FatIndexBitSize == 32) {
|
||
|
||
#ifndef __REACTOS__
|
||
#ifdef _MSC_VER
|
||
#pragma warning( suppress: 4213 )
|
||
#endif
|
||
FatEntry = *((PULONG)FatBuffer)++;
|
||
FatEntry = FatEntry & FAT32_ENTRY_MASK;
|
||
#else
|
||
FatEntry = *FatBuffer;
|
||
FatBuffer += 1;
|
||
FatEntry = FatEntry & FAT32_ENTRY_MASK;
|
||
#endif
|
||
|
||
} else {
|
||
|
||
FatEntry = *FatBuffer;
|
||
FatBuffer += 1;
|
||
}
|
||
}
|
||
|
||
if (CurrentRun == UnknownClusters) {
|
||
|
||
CurrentRun = (FatEntry == FAT_CLUSTER_AVAILABLE) ?
|
||
FreeClusters : AllocatedClusters;
|
||
}
|
||
|
||
//
|
||
// Are we switching from a free run to an allocated run?
|
||
//
|
||
|
||
if (CurrentRun == FreeClusters &&
|
||
FatEntry != FAT_CLUSTER_AVAILABLE) {
|
||
|
||
ClustersThisRun = FatIndex - StartIndexOfThisRun;
|
||
|
||
if (FreeClusterCount) {
|
||
|
||
*FreeClusterCount += ClustersThisRun;
|
||
CurrentWindow->ClustersFree += ClustersThisRun;
|
||
}
|
||
|
||
if (BitMap) {
|
||
|
||
RtlClearBits( BitMap,
|
||
StartIndexOfThisRun - StartIndex,
|
||
ClustersThisRun );
|
||
}
|
||
|
||
CurrentRun = AllocatedClusters;
|
||
StartIndexOfThisRun = FatIndex;
|
||
}
|
||
|
||
//
|
||
// Are we switching from an allocated run to a free run?
|
||
//
|
||
|
||
if (CurrentRun == AllocatedClusters &&
|
||
FatEntry == FAT_CLUSTER_AVAILABLE) {
|
||
|
||
ClustersThisRun = FatIndex - StartIndexOfThisRun;
|
||
|
||
if (BitMap) {
|
||
|
||
RtlSetBits( BitMap,
|
||
StartIndexOfThisRun - StartIndex,
|
||
ClustersThisRun );
|
||
}
|
||
|
||
CurrentRun = FreeClusters;
|
||
StartIndexOfThisRun = FatIndex;
|
||
}
|
||
|
||
//
|
||
// If the entry is marked bad, add it to the bad block MCB
|
||
//
|
||
|
||
if ((SetupWindows || (Vcb->NumberOfWindows == 1)) &&
|
||
(FatInterpretClusterType( Vcb, FatEntry ) == FatClusterBad)) {
|
||
|
||
//
|
||
// This cluster is marked bad.
|
||
// Add it to the BadBlockMcb.
|
||
//
|
||
|
||
Lbo = FatGetLboFromIndex( Vcb, FatIndex );
|
||
FatAddMcbEntry( Vcb, &Vcb->BadBlockMcb, BadClusterVbo, Lbo, ClusterSize );
|
||
BadClusterVbo += ClusterSize;
|
||
}
|
||
}
|
||
|
||
//
|
||
// If we finished the scan, then we know about all the possible bad clusters.
|
||
//
|
||
|
||
SetFlag( Vcb->VcbState, VCB_STATE_FLAG_BAD_BLOCKS_POPULATED);
|
||
|
||
//
|
||
// Now we have to record the final run we encountered
|
||
//
|
||
|
||
ClustersThisRun = FatIndex - StartIndexOfThisRun;
|
||
|
||
if (CurrentRun == FreeClusters) {
|
||
|
||
if (FreeClusterCount) {
|
||
|
||
*FreeClusterCount += ClustersThisRun;
|
||
CurrentWindow->ClustersFree += ClustersThisRun;
|
||
}
|
||
|
||
if (BitMap) {
|
||
|
||
RtlClearBits( BitMap,
|
||
StartIndexOfThisRun - StartIndex,
|
||
ClustersThisRun );
|
||
}
|
||
|
||
} else {
|
||
|
||
if (BitMap) {
|
||
|
||
RtlSetBits( BitMap,
|
||
StartIndexOfThisRun - StartIndex,
|
||
ClustersThisRun );
|
||
}
|
||
}
|
||
|
||
//
|
||
// And finish the last window if we are in setup.
|
||
//
|
||
|
||
if (SetupWindows) {
|
||
|
||
CurrentWindow->LastCluster = FatIndex - 1;
|
||
}
|
||
|
||
//
|
||
// Now switch the active window if required. We've succesfully gotten everything
|
||
// nailed down.
|
||
//
|
||
// If we were tracking the free cluster count, this means we should update the
|
||
// window. This is the case of FAT12/16 initialization.
|
||
//
|
||
|
||
if (SwitchToWindow) {
|
||
|
||
if (Vcb->FreeClusterBitMap.Buffer) {
|
||
|
||
ExFreePool( Vcb->FreeClusterBitMap.Buffer );
|
||
}
|
||
|
||
RtlInitializeBitMap( &Vcb->FreeClusterBitMap,
|
||
NewBitMapBuffer,
|
||
EndIndex - StartIndex + 1 );
|
||
|
||
NewBitMapBuffer = NULL;
|
||
|
||
Vcb->CurrentWindow = SwitchToWindow;
|
||
Vcb->ClusterHint = (ULONG)-1;
|
||
|
||
if (FreeClusterCount) {
|
||
|
||
NT_ASSERT( !SetupWindows );
|
||
|
||
Vcb->CurrentWindow->ClustersFree = *FreeClusterCount;
|
||
}
|
||
}
|
||
|
||
//
|
||
// Make sure plausible things occured ...
|
||
//
|
||
|
||
if (!SetupWindows && BitMapBuffer == NULL) {
|
||
|
||
ASSERT_CURRENT_WINDOW_GOOD( Vcb );
|
||
}
|
||
|
||
NT_ASSERT(Vcb->AllocationSupport.NumberOfFreeClusters <= Vcb->AllocationSupport.NumberOfClusters);
|
||
|
||
} _SEH2_FINALLY {
|
||
|
||
//
|
||
// Unpin the last bcb and drop the temporary bitmap buffer if it exists.
|
||
//
|
||
|
||
FatUnpinBcb( IrpContext, Bcb);
|
||
|
||
if (NewBitMapBuffer) {
|
||
|
||
ExFreePool( NewBitMapBuffer );
|
||
}
|
||
} _SEH2_END;
|
||
}
|
||
|