reactos操作系统实现(136)

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VfatMount@H_502_3@函数主要用来安装FAT文件卷，具体实现代码如下：

#001@H_502_3@ static NTSTATUS

#002@H_502_3@ VfatMount (PVFAT_IRP_CONTEXT IrpContext)

#003@H_502_3@ /*

#004@H_502_3@ * FUNCTION: Mount the filesystem

#005@H_502_3@ */

#006@H_502_3@ {

#007@H_502_3@ PDEVICE_OBJECT DeviceObject = NULL;

#008@H_502_3@ PDEVICE_EXTENSION DeviceExt = NULL;

#009@H_502_3@ BOOLEAN RecognizedFS;

#010@H_502_3@ NTSTATUS Status;

#011@H_502_3@ PVFATFCB Fcb = NULL;

#012@H_502_3@ PVFATFCB VolumeFcb = NULL;

#013@H_502_3@ PVFATCCB Ccb = NULL;

#014@H_502_3@ PDEVICE_OBJECT DeviceToMount;

#015@H_502_3@ PVPB Vpb;

FAT@H_502_3@的文件系统名称。

#016@H_502_3@ UNICODE_STRING NameU = RTL_CONSTANT_STRING(L"//$$Fat$$");

@H_502_3@操作系统文件卷名称。

#017@H_502_3@ UNICODE_STRING VolumeNameU = RTL_CONSTANT_STRING(L"//$$Volume$$");

#018@H_502_3@ ULONG HashTableSize;

#019@H_502_3@ ULONG eocMark;

#020@H_502_3@ FATINFO FatInfo;

#021@H_502_3@

#022@H_502_3@ DPRINT("VfatMount(IrpContext %p)/n",IrpContext);

#023@H_502_3@

#024@H_502_3@ ASSERT(IrpContext);

#025@H_502_3@

@H_502_3@如果当前请求的设备与FAT的设备不一致，就返回出错。

#026@H_502_3@ if (IrpContext->DeviceObject != VfatGlobalData->DeviceObject)

#027@H_502_3@ {

#028@H_502_3@ Status = STATUS_INVALID_DEVICE_REQUEST;

#029@H_502_3@ goto ByeBye;

#030@H_502_3@ @H_502_3@}

#031@H_502_3@

@H_502_3@获取当前要加载的设备。

#032@H_502_3@ DeviceToMount = IrpContext->Stack->Parameters.MountVolume.DeviceObject;

@H_502_3@获取卷描述信息。

#033@H_502_3@ Vpb = IrpContext->Stack->Parameters.MountVolume.Vpb;

#034

@H_502_3@在这里调用函数VfatHasFileSystem来判断要加载的设备是否为FAT文件系统设备，如果为FAT文件系统，RecognizedFS就返回TRUE，并且FatInfo返回FAT文件系统描述信息。

#035@H_502_3@ Status = VfatHasFileSystem (DeviceToMount,&RecognizedFS,&FatInfo);

#036@H_502_3@ if (!NT_SUCCESS(Status))

#037@H_502_3@ {

#038@H_502_3@ goto ByeBye;

#039@H_502_3@ }

#040

@H_502_3@如果不认识这个FAT的文件系统，就返回出错。

#041@H_502_3@ if (RecognizedFS == FALSE)

#042@H_502_3@ {

#043@H_502_3@ DPRINT("VFAT: Unrecognized Volume/n");

#044@H_502_3@ Status = STATUS_UNRECOGNIZED_VOLUME;

#045@H_502_3@ goto ByeBye;

#046@H_502_3@ }

#047@H_502_3@

@H_502_3@根据文件系统的类型来设置HASH表项的大小。

#048@H_502_3@ /* Use prime numbers for the table size */

#049@H_502_3@ if (FatInfo.FatType == FAT12)

#050@H_502_3@ {

#051@H_502_3@ HashTableSize = 4099; // 4096 = 4 * 1024

#052@H_502_3@ }

#053@H_502_3@ else if (FatInfo.FatType == FAT16 ||

#054@H_502_3@ FatInfo.FatType == FATX16)

#055@H_502_3@ {

#056@H_502_3@ HashTableSize = 16411; // 16384 = 16 * 1024

#057@H_502_3@ }

#058@H_502_3@ else

#059@H_502_3@ {

#060@H_502_3@ HashTableSize = 65537; // 65536 = 64 * 1024;

#061@H_502_3@ }

#062@H_502_3@ HashTableSize = FCB_HASH_TABLE_SIZE;

#063@H_502_3@ DPRINT("VFAT: Recognized volume/n");

@H_502_3@为当前的文件卷创建一个文件设备。

#064@H_502_3@ Status = IoCreateDevice(VfatGlobalData->DriverObject,

#065@H_502_3@ ROUND_UP(sizeof (DEVICE_EXTENSION),sizeof(ULONG)) + sizeof(HASHENTRY*) * HashTableSize,

#066@H_502_3@ NULL,

#067@H_502_3@ @H_502_3@FILE_DEVICE_DISK_FILE_SYSTEM,

#068@H_502_3@ 0,

#069@H_502_3@ FALSE,

#070@H_502_3@ &DeviceObject);

#071@H_502_3@ if (!NT_SUCCESS(Status))

#072@H_502_3@ {

#073@H_502_3@ goto ByeBye;

#074@H_502_3@ }

#075@H_502_3@

@H_502_3@设置设备属性。

#076@H_502_3@ DeviceObject->Flags = DeviceObject->Flags | DO_DIRECT_IO;

#077@H_502_3@ DeviceExt = (PVOID) DeviceObject->DeviceExtension;

#078@H_502_3@ RtlZeroMemory(DeviceExt,ROUND_UP(sizeof(DEVICE_EXTENSION),sizeof(ULONG)) + sizeof(HASHENTRY*) * HashTableSize);

#079@H_502_3@ DeviceExt->FcbHashTable = (HASHENTRY**)((ULONG_PTR)DeviceExt + ROUND_UP(sizeof(DEVICE_EXTENSION),sizeof(ULONG)));

#080@H_502_3@ DeviceExt->HashTableSize = HashTableSize;

#081@H_502_3@

@H_502_3@文件卷设备和磁盘设备使用同样的VPB。

#082@H_502_3@ /* use same vpb as device disk */

#083@H_502_3@ @H_502_3@DeviceObject->Vpb = Vpb;

#084@H_502_3@ DeviceToMount->Vpb = Vpb;

#085@H_502_3@

@H_502_3@安装磁盘设备到这个文件卷功能设备上。

#086@H_502_3@ Status = VfatMountDevice(DeviceExt,DeviceToMount);

#087@H_502_3@ if (!NT_SUCCESS(Status))

#088@H_502_3@ {

#089@H_502_3@ /* FIXME: delete device object */

#090@H_502_3@ goto ByeBye;

#091@H_502_3@ }

#092@H_502_3@

#093@H_502_3@ DPRINT("BytesPerSector:@H_502_3@ %d/n",DeviceExt->FatInfo.BytesPerSector);

#094@H_502_3@ DPRINT("SectorsPerCluster:@H_502_3@ %d/n",DeviceExt->FatInfo.SectorsPerCluster);

#095@H_502_3@ DPRINT("FATCount:@H_502_3@ %d/n",DeviceExt->FatInfo.FATCount);

#096@H_502_3@ DPRINT("FATSectors:@H_502_3@ %d/n",DeviceExt->FatInfo.FATSectors);

#097@H_502_3@ DPRINT("RootStart:@H_502_3@ %d/n",DeviceExt->FatInfo.rootStart);

#098@H_502_3@ DPRINT("DataStart:@H_502_3@ %d/n",DeviceExt->FatInfo.dataStart);

#099@H_502_3@ if (DeviceExt->FatInfo.FatType == FAT32)

#100@H_502_3@ {

#101@H_502_3@ DPRINT("RootCluster:@H_502_3@ %d/n",DeviceExt->FatInfo.RootCluster);

#102@H_502_3@ }

#103@H_502_3@

@H_502_3@根据不同的文件系统类型来进行回调函数设置。

#104@H_502_3@ switch (DeviceExt->FatInfo.FatType)

#105@H_502_3@ {

#106@H_502_3@ case FAT12:

#107@H_502_3@ DeviceExt->GetNextCluster = FAT12GetNextCluster;

#108@H_502_3@ DeviceExt->FindAndMarkAvailableCluster = FAT12FindAndMarkAvailableCluster;

#109@H_502_3@ DeviceExt->WriteCluster = FAT12WriteCluster;

#110@H_502_3@ DeviceExt->CleanShutBitMask = 0;

#111@H_502_3@ @H_502_3@break;

#112@H_502_3@

#113@H_502_3@ case FAT16:

#114@H_502_3@ case FATX16:

#115@H_502_3@ DeviceExt->GetNextCluster = FAT16GetNextCluster;

#116@H_502_3@ DeviceExt->FindAndMarkAvailableCluster = FAT16FindAndMarkAvailableCluster;

#117@H_502_3@ DeviceExt->WriteCluster = FAT16WriteCluster;

#118@H_502_3@ DeviceExt->CleanShutBitMask = 0x8000;

#119@H_502_3@ break;

#120@H_502_3@

#121@H_502_3@ case FAT32:

#122@H_502_3@ case FATX32:

#123@H_502_3@ DeviceExt->GetNextCluster = FAT32GetNextCluster;

#124@H_502_3@ DeviceExt->FindAndMarkAvailableCluster = FAT32FindAndMarkAvailableCluster;

#125@H_502_3@ DeviceExt->WriteCluster = FAT32WriteCluster;

#126@H_502_3@ DeviceExt->CleanShutBitMask = 0x80000000;

#127@H_502_3@ break;

#128@H_502_3@ }

#129@H_502_3@

#130@H_502_3@ if (DeviceExt->FatInfo.FatType == FATX16

#131@H_502_3@ || DeviceExt->FatInfo.FatType == FATX32)

#132@H_502_3@ {

#133@H_502_3@ DeviceExt->Flags |= VCB_IS_FATX;

#134@H_502_3@ DeviceExt->GetNextDirEntry = FATXGetNextDirEntry;

#135@H_502_3@ DeviceExt->BaseDateYear = 2000;

#136@H_502_3@ }

#137@H_502_3@ else

#138@H_502_3@ {

#139@H_502_3@ DeviceExt->GetNextDirEntry = FATGetNextDirEntry;

#140@H_502_3@ DeviceExt->BaseDateYear = 1980;

#141@H_502_3@ }

#142@H_502_3@

@H_502_3@设置文件系统功能设备的底层设备，以便把IRP传送给底层驱动处理。

#143@H_502_3@ DeviceExt->StorageDevice = DeviceToMount;

#144@H_502_3@ DeviceExt->StorageDevice->Vpb->DeviceObject = DeviceObject;

#145@H_502_3@ DeviceExt->StorageDevice->Vpb->RealDevice = DeviceExt->StorageDevice;

#146@H_502_3@ DeviceExt->StorageDevice->Vpb->Flags |= VPB_MOUNTED;

#147@H_502_3@ DeviceObject->StackSize = DeviceExt->StorageDevice->StackSize + 1;

#148@H_502_3@ DeviceObject->Flags &= ~DO_DEVICE_INITIALIZING;

#149@H_502_3@

#150@H_502_3@ DPRINT("FsDeviceObject %p/n",DeviceObject);

#151@H_502_3@

@H_502_3@初始化设备清除使用的共享资源。

#152@H_502_3@ /* Initialize this resource early ... it's used in VfatCleanup */

#153@H_502_3@ ExInitializeResourceLite(&DeviceExt->DirResource);

#154@H_502_3@

@H_502_3@创建流文件对象用来表示一个文件卷。

#155@H_502_3@ DeviceExt->FATFileObject = IoCreateStreamFileObject(NULL,DeviceExt->StorageDevice);

@H_502_3@创建一块文件控制块。

#156@H_502_3@ Fcb = vfatNewFCB(DeviceExt,&NameU);

#157@H_502_3@ if (Fcb == NULL)

#158@H_502_3@ {

#159@H_502_3@ Status = STATUS_INSUFFICIENT_RESOURCES;

#160@H_502_3@ goto ByeBye;

#161@H_502_3@ }

#162@H_502_3@ Ccb = ExAllocateFromNPagedLookasideList(&VfatGlobalData->CcbLookasideList);

#163@H_502_3@ if (Ccb == NULL)

#164@H_502_3@ {

#165@H_502_3@ Status =@H_502_3@ STATUS_INSUFFICIENT_RESOURCES;

#166@H_502_3@ goto ByeBye;

#167@H_502_3@ }

#168@H_502_3@

@H_502_3@设置扩展属性。

#169@H_502_3@ RtlZeroMemory(Ccb,sizeof (VFATCCB));

#170@H_502_3@ DeviceExt->FATFileObject->FsContext = Fcb;

#171@H_502_3@ DeviceExt->FATFileObject->FsContext2 = Ccb;

#172@H_502_3@ DeviceExt->FATFileObject->SectionObjectPointer = &Fcb->SectionObjectPointers;

#173@H_502_3@ DeviceExt->FATFileObject->PrivateCacheMap = NULL;

#174@H_502_3@ DeviceExt->FATFileObject->Vpb = DeviceObject->Vpb;

#175@H_502_3@ Fcb->FileObject = DeviceExt->FATFileObject;

#176@H_502_3@

@H_502_3@设置为FAT标识。

#177@H_502_3@ Fcb->Flags |= FCB_IS_FAT;

#178@H_502_3@

#179@H_502_3@ Fcb->RFCB.FileSize.QuadPart = DeviceExt->FatInfo.FATSectors * DeviceExt->FatInfo.BytesPerSector;

#180@H_502_3@ Fcb->RFCB.ValidDataLength = Fcb->RFCB.FileSize;

#181@H_502_3@ Fcb->RFCB.AllocationSize = Fcb->RFCB.FileSize;

#182@H_502_3@

@H_502_3@初始化文件读写的缓冲区。

#183@H_502_3@ CcInitializeCacheMap(DeviceExt->FATFileObject,

#184@H_502_3@ (PCC_FILE_SIZES)(&Fcb->RFCB.AllocationSize),

#185@H_502_3@ TRUE,

#186@H_502_3@ &VfatGlobalData->CacheMgrCallbacks,

#187@H_502_3@ Fcb);

#188@H_502_3@

#189@H_502_3@ DeviceExt->LastAvailableCluster = 2;

#190@H_502_3@ ExInitializeResourceLite(&DeviceExt->FatResource);

#191@H_502_3@

#192@H_502_3@ InitializeListHead(&DeviceExt->FcbListHead);

#193@H_502_3@

@H_502_3@创建文件卷控制块。

#194@H_502_3@ VolumeFcb = vfatNewFCB(DeviceExt,&VolumeNameU);

#195@H_502_3@ if (VolumeFcb == NULL)

#196@H_502_3@ {

#197@H_502_3@ Status = STATUS_INSUFFICIENT_RESOURCES;

#198@H_502_3@ goto ByeBye;

#199@H_502_3@ }

#200@H_502_3@ VolumeFcb->Flags = FCB_IS_VOLUME;

#201@H_502_3@ VolumeFcb->RFCB.FileSize.QuadPart = DeviceExt->FatInfo.Sectors * DeviceExt->FatInfo.BytesPerSector;

#202@H_502_3@ VolumeFcb->RFCB.ValidDataLength = VolumeFcb->RFCB.FileSize;

#203@H_502_3@ VolumeFcb->RFCB.AllocationSize = VolumeFcb->RFCB.FileSize;

#204@H_502_3@ DeviceExt->VolumeFcb = VolumeFcb;

#205@H_502_3@

#206@H_502_3@ ExAcquireResourceExclusiveLite(&VfatGlobalData->VolumeListLock,TRUE);

#207@H_502_3@ InsertHeadList(&VfatGlobalData->VolumeListHead,&DeviceExt->VolumeListEntry);

#208@H_502_3@ ExReleaseResourceLite(&VfatGlobalData->VolumeListLock);

#209

@H_502_3@读取文件卷序号。

#210@H_502_3@ @H_502_3@/* read serial number */

#211@H_502_3@ DeviceObject->Vpb->SerialNumber = DeviceExt->FatInfo.VolumeID;

#212@H_502_3@

@H_502_3@读取文件卷标。

#213@H_502_3@ /* read volume label */

#214@H_502_3@ ReadVolumeLabel(DeviceExt,@H_502_3@ DeviceObject->Vpb);

#215@H_502_3@

@H_502_3@读取并清除关闭标志。

#216@H_502_3@ /* read clean shutdown bit status */

#217@H_502_3@ Status = GetNextCluster(DeviceExt,1,&eocMark);

#218@H_502_3@ if (NT_SUCCESS(Status))

#219@H_502_3@ {

#220@H_502_3@ if (eocMark & DeviceExt->CleanShutBitMask)

#221@H_502_3@ {

#222@H_502_3@ /* unset clean shutdown bit */

#223@H_502_3@ eocMark &= ~DeviceExt->CleanShutBitMask;

#224@H_502_3@ WriteCluster(DeviceExt,eocMark);

#225@H_502_3@ VolumeFcb->Flags |= VCB_CLEAR_DIRTY;

#226@H_502_3@ }

#227@H_502_3@ }

#228@H_502_3@ VolumeFcb->Flags |= VCB_IS_DIRTY;

#229@H_502_3@

#230@H_502_3@ Status = STATUS_SUCCESS;

#231@H_502_3@ ByeBye:

#232@H_502_3@

#233@H_502_3@ if (!NT_SUCCESS(Status))

#234@H_502_3@ {

#235@H_502_3@ // cleanup

#236@H_502_3@ if (DeviceExt && DeviceExt->FATFileObject)

#237@H_502_3@ ObDereferenceObject (DeviceExt->FATFileObject);

#238@H_502_3@ if (Fcb)

#239@H_502_3@ vfatDestroyFCB(Fcb);

#240@H_502_3@ if (Ccb)

#241@H_502_3@ vfatDestroyCCB(Ccb);

#242@H_502_3@ if (DeviceObject)

#243@H_502_3@ IoDeleteDevice(DeviceObject);

#244@H_502_3@ if (VolumeFcb)

#245@H_502_3@ vfatDestroyFCB(VolumeFcb);

#246@H_502_3@ }

#247@H_502_3@ return Status;

#248}

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