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109 lines
2.1 KiB
C
109 lines
2.1 KiB
C
/*
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* COPYRIGHT: See COPYING in the top level directory
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* PROJECT: ReactOS kernel
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* FILE: services/fs/minix/minix.c
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* PURPOSE: Minix FSD
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* PROGRAMMER: David Welch (welch@mcmail.com)
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* UPDATE HISTORY:
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*/
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/* INCLUDES *****************************************************************/
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#include <ntddk.h>
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//#define NDEBUG
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#include <debug.h>
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#include "minix.h"
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/* FUNCTIONS ****************************************************************/
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static unsigned int MinixGetBlock(PDEVICE_OBJECT DeviceObject,
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PMINIX_DEVICE_EXTENSION DeviceExt,
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struct minix_inode* inode,
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ULONG FileOffset)
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{
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int block;
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PVOID BaseAddress;
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ULONG blk;
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blk = FileOffset / BLOCKSIZE;
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DPRINT("MinixGetBlock(inode %x, blk %d)\n",inode,blk);
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/*
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* The first few blocks are available in the inode
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*/
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if (blk < 7)
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{
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block = inode->i_zone[blk];
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return(block);
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}
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blk = blk - 7;
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/*
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* Retrieve a single-indirect block
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*/
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if (blk < 512)
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{
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block = inode->i_zone[7];
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BaseAddress = ExAllocatePool(NonPagedPool, 512);
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MinixReadSector(DeviceObject,
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block,
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BaseAddress);
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block = ((PUSHORT)(BaseAddress))[blk];
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ExFreePool(BaseAddress);
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return(block);
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}
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/*
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* Get a double indirect block
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*/
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blk = blk - 512;
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block = inode->i_zone[8];
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BaseAddress = ExAllocatePool(NonPagedPool, 512);
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MinixReadSector(DeviceObject,
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block,
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BaseAddress);
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block = ((PUSHORT)BaseAddress)[(blk>>9)&511];
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ExFreePool(BaseAddress);
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BaseAddress = ExAllocatePool(NonPagedPool, 512);
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MinixReadSector(DeviceObject,
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block,
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BaseAddress);
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block = ((PUSHORT)BaseAddress)[blk&512];
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ExFreePool(BaseAddress);
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return(block);
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}
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NTSTATUS MinixReadBlock(PDEVICE_OBJECT DeviceObject,
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PMINIX_DEVICE_EXTENSION DeviceExt,
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struct minix_inode* inode,
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ULONG FileOffset,
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PULONG DiskOffset)
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{
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unsigned int block;
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DPRINT("MinixReadBlock()\n");
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block = MinixGetBlock(DeviceObject, DeviceExt,inode, FileOffset);
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(*DiskOffset) = block * BLOCKSIZE;
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return(STATUS_SUCCESS);
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}
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