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Reads of the FAT on FAT32 filesystems go through the cache, writes are

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svn path=/trunk/; revision=1604
This commit is contained in:
David Welch 2001-02-06 00:41:19 +00:00
parent 076c1c6ac3
commit b2fe7525bf
1 changed files with 31 additions and 12 deletions
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43
reactos/drivers/fs/vfat/fat.c
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@ -1,5 +1,5 @@
/*
* $Id: fat.c,v 1.16 2001/01/16 23:22:03 dwelch Exp $
* $Id: fat.c,v 1.17 2001/02/06 00:41:19 dwelch Exp $
*
* COPYRIGHT: See COPYING in the top level directory
* PROJECT: ReactOS kernel
@ -31,25 +31,41 @@ Fat32GetNextCluster (PDEVICE_EXTENSION DeviceExt,
* disk read
*/
{
ULONG FATsector;
ULONG FATeis;
PULONG Block;
PVOID BaseAddress;
BOOLEAN Valid;
PCACHE_SEGMENT CacheSeg;
NTSTATUS Status;
ULONG FATOffset;
Block = ExAllocatePool (NonPagedPool, 1024);
FATsector = CurrentCluster / (512 / sizeof (ULONG));
FATeis = CurrentCluster - (FATsector * (512 / sizeof (ULONG)));
Status = VfatReadSectors (DeviceExt->StorageDevice,
(ULONG) (DeviceExt->FATStart + FATsector), 1,
(UCHAR *) Block);
FATOffset = (DeviceExt->FATStart * BLOCKSIZE) +
(CurrentCluster * sizeof(ULONG));
Status = CcRequestCacheSegment(DeviceExt->StorageBcb,
PAGE_ROUND_DOWN(FATOffset),
&BaseAddress,
&Valid,
&CacheSeg);
if (!NT_SUCCESS(Status))
{
return(Status);
}
CurrentCluster = Block[FATeis];
if (!Valid)
{
Status = VfatReadSectors(DeviceExt->StorageDevice,
PAGE_ROUND_DOWN(FATOffset) / BLOCKSIZE,
PAGESIZE / BLOCKSIZE,
BaseAddress);
if (!NT_SUCCESS(Status))
{
CcReleaseCacheSegment(DeviceExt->StorageBcb, CacheSeg, FALSE);
return(Status);
}
}
CurrentCluster = *((PUSHORT)BaseAddress + (FATOffset % PAGESIZE));
if (CurrentCluster >= 0xffffff8 && CurrentCluster <= 0xfffffff)
CurrentCluster = 0xffffffff;
ExFreePool (Block);
CcReleaseCacheSegment(DeviceExt->StorageBcb, CacheSeg, TRUE);
*NextCluster = CurrentCluster;
return (STATUS_SUCCESS);
}
@ -571,6 +587,7 @@ FAT32WriteCluster (PDEVICE_EXTENSION DeviceExt, ULONG ClusterToWrite,
* FUNCTION: Writes a cluster to the FAT32 physical tables
*/
{
#if 0
ULONG FATsector;
ULONG FATeis;
PUSHORT Block;
@ -596,6 +613,8 @@ FAT32WriteCluster (PDEVICE_EXTENSION DeviceExt, ULONG ClusterToWrite,
Start += pBoot->FATSectors;
}
ExFreePool (Block);
#endif
KeBugCheck(0);
}
NTSTATUS