reactos/drivers/filesystems/fastfat/fsctl.c

/*
 *  ReactOS kernel
 *  Copyright (C) 2002 ReactOS Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
/*
 * COPYRIGHT:        See COPYING in the top level directory
 * PROJECT:          ReactOS kernel
 * FILE:             drivers/fs/vfat/fsctl.c
 * PURPOSE:          VFAT Filesystem
 */

/* INCLUDES *****************************************************************/

#include "vfat.h"

#define NDEBUG
#include <debug.h>

/* FUNCTIONS ****************************************************************/

#define  CACHEPAGESIZE(pDeviceExt) ((pDeviceExt)->FatInfo.BytesPerCluster > PAGE_SIZE ? \
                                    (pDeviceExt)->FatInfo.BytesPerCluster : PAGE_SIZE)

static
NTSTATUS
VfatHasFileSystem(
    PDEVICE_OBJECT DeviceToMount,
    PBOOLEAN RecognizedFS,
    PFATINFO pFatInfo)
{
    NTSTATUS Status;
    PARTITION_INFORMATION PartitionInfo;
    DISK_GEOMETRY DiskGeometry;
    FATINFO FatInfo;
    ULONG Size;
    ULONG Sectors;
    LARGE_INTEGER Offset;
    struct _BootSector* Boot;
    struct _BootSectorFatX* BootFatX;
    BOOLEAN PartitionInfoIsValid = FALSE;

    DPRINT("VfatHasFileSystem\n");

    *RecognizedFS = FALSE;

    Size = sizeof(DISK_GEOMETRY);
    Status = VfatBlockDeviceIoControl(DeviceToMount,
                                      IOCTL_DISK_GET_DRIVE_GEOMETRY,
                                      NULL,
                                      0,
                                      &DiskGeometry,
                                      &Size,
                                      FALSE);
    if (!NT_SUCCESS(Status))
    {
        DPRINT("VfatBlockDeviceIoControl faild (%x)\n", Status);
        return Status;
    }

    FatInfo.FixedMedia = DiskGeometry.MediaType == FixedMedia ? TRUE : FALSE;
    if (DiskGeometry.MediaType == FixedMedia || DiskGeometry.MediaType == RemovableMedia)
    {
        // We have found a hard disk
        Size = sizeof(PARTITION_INFORMATION);
        Status = VfatBlockDeviceIoControl(DeviceToMount,
                                          IOCTL_DISK_GET_PARTITION_INFO,
                                          NULL,
                                          0,
                                          &PartitionInfo,
                                          &Size,
                                          FALSE);
        if (!NT_SUCCESS(Status))
        {
            DPRINT("VfatBlockDeviceIoControl faild (%x)\n", Status);
            return Status;
        }

        PartitionInfoIsValid = TRUE;
        DPRINT("Partition Information:\n");
        DPRINT("StartingOffset      %I64x\n", PartitionInfo.StartingOffset.QuadPart  / 512);
        DPRINT("PartitionLength     %I64x\n", PartitionInfo.PartitionLength.QuadPart / 512);
        DPRINT("HiddenSectors       %u\n", PartitionInfo.HiddenSectors);
        DPRINT("PartitionNumber     %u\n", PartitionInfo.PartitionNumber);
        DPRINT("PartitionType       %u\n", PartitionInfo.PartitionType);
        DPRINT("BootIndicator       %u\n", PartitionInfo.BootIndicator);
        DPRINT("RecognizedPartition %u\n", PartitionInfo.RecognizedPartition);
        DPRINT("RewritePartition    %u\n", PartitionInfo.RewritePartition);
        if (PartitionInfo.PartitionType)
        {
            if (PartitionInfo.PartitionType == PARTITION_FAT_12       ||
                PartitionInfo.PartitionType == PARTITION_FAT_16       ||
                PartitionInfo.PartitionType == PARTITION_HUGE         ||
                PartitionInfo.PartitionType == PARTITION_FAT32        ||
                PartitionInfo.PartitionType == PARTITION_FAT32_XINT13 ||
                PartitionInfo.PartitionType == PARTITION_XINT13)
            {
                *RecognizedFS = TRUE;
            }
        }
        else if (DiskGeometry.MediaType == RemovableMedia &&
                 PartitionInfo.PartitionNumber > 0 &&
                 PartitionInfo.StartingOffset.QuadPart == 0 &&
                 PartitionInfo.PartitionLength.QuadPart > 0)
        {
            /* This is possible a removable media formated as super floppy */
            *RecognizedFS = TRUE;
        }
    }
    else if (DiskGeometry.MediaType == Unknown)
    {
        /*
         * Floppy disk driver can return Unknown as media type if it
         * doesn't know yet what floppy in the drive really is. This is
         * perfectly correct to do under Windows.
         */
        *RecognizedFS = TRUE;
        DiskGeometry.BytesPerSector = 512;
    }
    else
    {
        *RecognizedFS = TRUE;
    }

    if (*RecognizedFS)
    {
        Boot = ExAllocatePoolWithTag(NonPagedPool, DiskGeometry.BytesPerSector, TAG_VFAT);
        if (Boot == NULL)
        {
           return STATUS_INSUFFICIENT_RESOURCES;
        }

        Offset.QuadPart = 0;

        /* Try to recognize FAT12/FAT16/FAT32 partitions */
        Status = VfatReadDisk(DeviceToMount, &Offset, DiskGeometry.BytesPerSector, (PUCHAR) Boot, FALSE);
        if (NT_SUCCESS(Status))
        {
            if (Boot->Signatur1 != 0xaa55)
            {
                *RecognizedFS = FALSE;
            }

            if (*RecognizedFS &&
                Boot->BytesPerSector != 512 &&
                Boot->BytesPerSector != 1024 &&
                Boot->BytesPerSector != 2048 &&
                Boot->BytesPerSector != 4096)
            {
                DPRINT1("BytesPerSector %u\n", Boot->BytesPerSector);
                *RecognizedFS = FALSE;
            }

            if (*RecognizedFS &&
                Boot->FATCount != 1 &&
                Boot->FATCount != 2)
            {
                DPRINT1("FATCount %u\n", Boot->FATCount);
                *RecognizedFS = FALSE;
            }

            if (*RecognizedFS &&
                Boot->Media != 0xf0 &&
                Boot->Media != 0xf8 &&
                Boot->Media != 0xf9 &&
                Boot->Media != 0xfa &&
                Boot->Media != 0xfb &&
                Boot->Media != 0xfc &&
                Boot->Media != 0xfd &&
                Boot->Media != 0xfe &&
                Boot->Media != 0xff)
            {
                DPRINT1("Media             %02x\n", Boot->Media);
                *RecognizedFS = FALSE;
            }

            if (*RecognizedFS &&
                Boot->SectorsPerCluster != 1 &&
                Boot->SectorsPerCluster != 2 &&
                Boot->SectorsPerCluster != 4 &&
                Boot->SectorsPerCluster != 8 &&
                Boot->SectorsPerCluster != 16 &&
                Boot->SectorsPerCluster != 32 &&
                Boot->SectorsPerCluster != 64 &&
                Boot->SectorsPerCluster != 128)
            {
                DPRINT1("SectorsPerCluster %02x\n", Boot->SectorsPerCluster);
                *RecognizedFS = FALSE;
            }

            if (*RecognizedFS &&
                Boot->BytesPerSector * Boot->SectorsPerCluster > 32 * 1024)
            {
                DPRINT1("ClusterSize %dx\n", Boot->BytesPerSector * Boot->SectorsPerCluster);
                *RecognizedFS = FALSE;
            }

            if (*RecognizedFS)
            {
                FatInfo.VolumeID = Boot->VolumeID;
                FatInfo.FATStart = Boot->ReservedSectors;
                FatInfo.FATCount = Boot->FATCount;
                FatInfo.FATSectors = Boot->FATSectors ? Boot->FATSectors : ((struct _BootSector32*) Boot)->FATSectors32;
                FatInfo.BytesPerSector = Boot->BytesPerSector;
                FatInfo.SectorsPerCluster = Boot->SectorsPerCluster;
                FatInfo.BytesPerCluster = FatInfo.BytesPerSector * FatInfo.SectorsPerCluster;
                FatInfo.rootDirectorySectors = ((Boot->RootEntries * 32) + Boot->BytesPerSector - 1) / Boot->BytesPerSector;
                FatInfo.rootStart = FatInfo.FATStart + FatInfo.FATCount * FatInfo.FATSectors;
                FatInfo.dataStart = FatInfo.rootStart + FatInfo.rootDirectorySectors;
                FatInfo.Sectors = Sectors = Boot->Sectors ? Boot->Sectors : Boot->SectorsHuge;
                Sectors -= Boot->ReservedSectors + FatInfo.FATCount * FatInfo.FATSectors + FatInfo.rootDirectorySectors;
                FatInfo.NumberOfClusters = Sectors / Boot->SectorsPerCluster;
                if (FatInfo.NumberOfClusters < 4085)
                {
                    DPRINT("FAT12\n");
                    FatInfo.FatType = FAT12;
                    FatInfo.RootCluster = (FatInfo.rootStart - 1) / FatInfo.SectorsPerCluster;
                }
                else if (FatInfo.NumberOfClusters >= 65525)
                {
                    DPRINT("FAT32\n");
                    FatInfo.FatType = FAT32;
                    FatInfo.RootCluster = ((struct _BootSector32*) Boot)->RootCluster;
                    FatInfo.rootStart = FatInfo.dataStart + ((FatInfo.RootCluster - 2) * FatInfo.SectorsPerCluster);
                    FatInfo.VolumeID = ((struct _BootSector32*) Boot)->VolumeID;
                }
                else
                {
                    DPRINT("FAT16\n");
                    FatInfo.FatType = FAT16;
                    FatInfo.RootCluster = FatInfo.rootStart / FatInfo.SectorsPerCluster;
                }

                if (PartitionInfoIsValid &&
                    FatInfo.Sectors > PartitionInfo.PartitionLength.QuadPart / FatInfo.BytesPerSector)
                {
                    *RecognizedFS = FALSE;
                }

                if (pFatInfo && *RecognizedFS)
                {
                    *pFatInfo = FatInfo;
                }
            }
        }

        ExFreePool(Boot);
    }

    if (!*RecognizedFS && PartitionInfoIsValid)
    {
        BootFatX = ExAllocatePoolWithTag(NonPagedPool, sizeof(struct _BootSectorFatX), TAG_VFAT);
        if (BootFatX == NULL)
        {
            *RecognizedFS=FALSE;
            return STATUS_INSUFFICIENT_RESOURCES;
        }

        Offset.QuadPart = 0;

        /* Try to recognize FATX16/FATX32 partitions (Xbox) */
        Status = VfatReadDisk(DeviceToMount, &Offset, sizeof(struct _BootSectorFatX), (PUCHAR) BootFatX, FALSE);
        if (NT_SUCCESS(Status))
        {
            *RecognizedFS = TRUE;
            if (BootFatX->SysType[0] != 'F' ||
                BootFatX->SysType[1] != 'A' ||
                BootFatX->SysType[2] != 'T' ||
                BootFatX->SysType[3] != 'X')
            {
                DPRINT1("SysType %c%c%c%c\n", BootFatX->SysType[0], BootFatX->SysType[1], BootFatX->SysType[2], BootFatX->SysType[3]);
                *RecognizedFS=FALSE;
            }

            if (*RecognizedFS &&
                BootFatX->SectorsPerCluster != 1 &&
                BootFatX->SectorsPerCluster != 2 &&
                BootFatX->SectorsPerCluster != 4 &&
                BootFatX->SectorsPerCluster != 8 &&
                BootFatX->SectorsPerCluster != 16 &&
                BootFatX->SectorsPerCluster != 32 &&
                BootFatX->SectorsPerCluster != 64 &&
                BootFatX->SectorsPerCluster != 128)
            {
                DPRINT1("SectorsPerCluster %lu\n", BootFatX->SectorsPerCluster);
                *RecognizedFS=FALSE;
            }

            if (*RecognizedFS)
            {
                FatInfo.BytesPerSector = DiskGeometry.BytesPerSector;
                FatInfo.SectorsPerCluster = BootFatX->SectorsPerCluster;
                FatInfo.rootDirectorySectors = BootFatX->SectorsPerCluster;
                FatInfo.BytesPerCluster = BootFatX->SectorsPerCluster * DiskGeometry.BytesPerSector;
                FatInfo.Sectors = (ULONG)(PartitionInfo.PartitionLength.QuadPart / DiskGeometry.BytesPerSector);
                if (FatInfo.Sectors / FatInfo.SectorsPerCluster < 65525)
                {
                    DPRINT("FATX16\n");
                    FatInfo.FatType = FATX16;
                }
                else
                {
                    DPRINT("FATX32\n");
                    FatInfo.FatType = FATX32;
                }
                FatInfo.VolumeID = BootFatX->VolumeID;
                FatInfo.FATStart = sizeof(struct _BootSectorFatX) / DiskGeometry.BytesPerSector;
                FatInfo.FATCount = BootFatX->FATCount;
                FatInfo.FATSectors =
                    ROUND_UP(FatInfo.Sectors / FatInfo.SectorsPerCluster * (FatInfo.FatType == FATX16 ? 2 : 4), 4096) /
                    FatInfo.BytesPerSector;
                FatInfo.rootStart = FatInfo.FATStart + FatInfo.FATCount * FatInfo.FATSectors;
                FatInfo.RootCluster = (FatInfo.rootStart - 1) / FatInfo.SectorsPerCluster;
                FatInfo.dataStart = FatInfo.rootStart + FatInfo.rootDirectorySectors;
                FatInfo.NumberOfClusters = (FatInfo.Sectors - FatInfo.dataStart) / FatInfo.SectorsPerCluster;

                if (pFatInfo && *RecognizedFS)
                {
                    *pFatInfo = FatInfo;
                }
            }
        }
        ExFreePool(BootFatX);
    }

    DPRINT("VfatHasFileSystem done\n");
    return Status;
}

/*
 * FUNCTION: Mounts the device
 */
static
NTSTATUS
VfatMountDevice(
    PDEVICE_EXTENSION DeviceExt,
    PDEVICE_OBJECT DeviceToMount)
{
    NTSTATUS Status;
    BOOLEAN RecognizedFS;

    DPRINT("Mounting VFAT device...\n");

    Status = VfatHasFileSystem(DeviceToMount, &RecognizedFS, &DeviceExt->FatInfo);
    if (!NT_SUCCESS(Status))
    {
        return Status;
    }
    DPRINT("MountVfatdev %u, PAGE_SIZE = %d\n", DeviceExt->FatInfo.BytesPerCluster, PAGE_SIZE);

    return STATUS_SUCCESS;
}


/*
 * FUNCTION: Mount the filesystem
 */
static
NTSTATUS
VfatMount(
    PVFAT_IRP_CONTEXT IrpContext)
{
    PDEVICE_OBJECT DeviceObject = NULL;
    PDEVICE_EXTENSION DeviceExt = NULL;
    BOOLEAN RecognizedFS;
    NTSTATUS Status;
    PVFATFCB Fcb = NULL;
    PVFATFCB VolumeFcb = NULL;
    PVFATCCB Ccb = NULL;
    PDEVICE_OBJECT DeviceToMount;
    PVPB Vpb;
    UNICODE_STRING NameU = RTL_CONSTANT_STRING(L"\\$$Fat$$");
    UNICODE_STRING VolumeNameU = RTL_CONSTANT_STRING(L"\\$$Volume$$");
    ULONG HashTableSize;
    ULONG eocMark;
    FATINFO FatInfo;

    DPRINT("VfatMount(IrpContext %p)\n", IrpContext);

    ASSERT(IrpContext);

    if (IrpContext->DeviceObject != VfatGlobalData->DeviceObject)
    {
        Status = STATUS_INVALID_DEVICE_REQUEST;
        goto ByeBye;
    }

    DeviceToMount = IrpContext->Stack->Parameters.MountVolume.DeviceObject;
    Vpb = IrpContext->Stack->Parameters.MountVolume.Vpb;

    Status = VfatHasFileSystem(DeviceToMount, &RecognizedFS, &FatInfo);
    if (!NT_SUCCESS(Status))
    {
        goto ByeBye;
    }

    if (RecognizedFS == FALSE)
    {
        DPRINT("VFAT: Unrecognized Volume\n");
        Status = STATUS_UNRECOGNIZED_VOLUME;
        goto ByeBye;
    }

    /* Use prime numbers for the table size */
    if (FatInfo.FatType == FAT12)
    {
        HashTableSize = 4099; // 4096 = 4 * 1024
    }
    else if (FatInfo.FatType == FAT16 ||
             FatInfo.FatType == FATX16)
    {
        HashTableSize = 16411; // 16384 = 16 * 1024
    }
    else
    {
        HashTableSize = 65537; // 65536 = 64 * 1024;
    }
    HashTableSize = FCB_HASH_TABLE_SIZE;
    DPRINT("VFAT: Recognized volume\n");
    Status = IoCreateDevice(VfatGlobalData->DriverObject,
                            ROUND_UP(sizeof (DEVICE_EXTENSION), sizeof(ULONG)) + sizeof(HASHENTRY*) * HashTableSize,
                            NULL,
                            FILE_DEVICE_DISK_FILE_SYSTEM,
                            DeviceToMount->Characteristics,
                            FALSE,
                            &DeviceObject);
    if (!NT_SUCCESS(Status))
    {
        goto ByeBye;
    }

    DeviceObject->Flags = DeviceObject->Flags | DO_DIRECT_IO;
    DeviceExt = (PVOID) DeviceObject->DeviceExtension;
    RtlZeroMemory(DeviceExt, ROUND_UP(sizeof(DEVICE_EXTENSION), sizeof(ULONG)) + sizeof(HASHENTRY*) * HashTableSize);
    DeviceExt->FcbHashTable = (HASHENTRY**)((ULONG_PTR)DeviceExt + ROUND_UP(sizeof(DEVICE_EXTENSION), sizeof(ULONG)));
    DeviceExt->HashTableSize = HashTableSize;

    /* use same vpb as device disk */
    DeviceObject->Vpb = Vpb;
    DeviceToMount->Vpb = Vpb;

    Status = VfatMountDevice(DeviceExt, DeviceToMount);
    if (!NT_SUCCESS(Status))
    {
        /* FIXME: delete device object */
        goto ByeBye;
    }

    DPRINT("BytesPerSector:     %u\n", DeviceExt->FatInfo.BytesPerSector);
    DPRINT("SectorsPerCluster:  %u\n", DeviceExt->FatInfo.SectorsPerCluster);
    DPRINT("FATCount:           %u\n", DeviceExt->FatInfo.FATCount);
    DPRINT("FATSectors:         %u\n", DeviceExt->FatInfo.FATSectors);
    DPRINT("RootStart:          %u\n", DeviceExt->FatInfo.rootStart);
    DPRINT("DataStart:          %u\n", DeviceExt->FatInfo.dataStart);
    if (DeviceExt->FatInfo.FatType == FAT32)
    {
        DPRINT("RootCluster:        %u\n", DeviceExt->FatInfo.RootCluster);
    }

    switch (DeviceExt->FatInfo.FatType)
    {
        case FAT12:
            DeviceExt->GetNextCluster = FAT12GetNextCluster;
            DeviceExt->FindAndMarkAvailableCluster = FAT12FindAndMarkAvailableCluster;
            DeviceExt->WriteCluster = FAT12WriteCluster;
            DeviceExt->CleanShutBitMask = 0;
            break;

        case FAT16:
        case FATX16:
            DeviceExt->GetNextCluster = FAT16GetNextCluster;
            DeviceExt->FindAndMarkAvailableCluster = FAT16FindAndMarkAvailableCluster;
            DeviceExt->WriteCluster = FAT16WriteCluster;
            DeviceExt->CleanShutBitMask = 0x8000;
            break;

        case FAT32:
        case FATX32:
            DeviceExt->GetNextCluster = FAT32GetNextCluster;
            DeviceExt->FindAndMarkAvailableCluster = FAT32FindAndMarkAvailableCluster;
            DeviceExt->WriteCluster = FAT32WriteCluster;
            DeviceExt->CleanShutBitMask = 0x80000000;
            break;
    }

    if (DeviceExt->FatInfo.FatType == FATX16 ||
        DeviceExt->FatInfo.FatType == FATX32)
    {
        DeviceExt->Flags |= VCB_IS_FATX;
        DeviceExt->GetNextDirEntry = FATXGetNextDirEntry;
        DeviceExt->BaseDateYear = 2000;
    }
    else
    {
        DeviceExt->GetNextDirEntry = FATGetNextDirEntry;
        DeviceExt->BaseDateYear = 1980;
    }

    DeviceExt->StorageDevice = DeviceToMount;
    DeviceExt->StorageDevice->Vpb->DeviceObject = DeviceObject;
    DeviceExt->StorageDevice->Vpb->RealDevice = DeviceExt->StorageDevice;
    DeviceExt->StorageDevice->Vpb->Flags |= VPB_MOUNTED;
    DeviceObject->StackSize = DeviceExt->StorageDevice->StackSize + 1;
    DeviceObject->Flags &= ~DO_DEVICE_INITIALIZING;

    DPRINT("FsDeviceObject %p\n", DeviceObject);

    /* Initialize this resource early ... it's used in VfatCleanup */
    ExInitializeResourceLite(&DeviceExt->DirResource);

    DeviceExt->FATFileObject = IoCreateStreamFileObject(NULL, DeviceExt->StorageDevice);
    Fcb = vfatNewFCB(DeviceExt, &NameU);
    if (Fcb == NULL)
    {
        Status = STATUS_INSUFFICIENT_RESOURCES;
        goto ByeBye;
    }

    Ccb = ExAllocateFromNPagedLookasideList(&VfatGlobalData->CcbLookasideList);
    if (Ccb == NULL)
    {
        Status =  STATUS_INSUFFICIENT_RESOURCES;
        goto ByeBye;
    }

    RtlZeroMemory(Ccb, sizeof (VFATCCB));
    DeviceExt->FATFileObject->FsContext = Fcb;
    DeviceExt->FATFileObject->FsContext2 = Ccb;
    DeviceExt->FATFileObject->SectionObjectPointer = &Fcb->SectionObjectPointers;
    DeviceExt->FATFileObject->PrivateCacheMap = NULL;
    DeviceExt->FATFileObject->Vpb = DeviceObject->Vpb;
    Fcb->FileObject = DeviceExt->FATFileObject;

    Fcb->Flags |= FCB_IS_FAT;

    Fcb->RFCB.FileSize.QuadPart = DeviceExt->FatInfo.FATSectors * DeviceExt->FatInfo.BytesPerSector;
    Fcb->RFCB.ValidDataLength = Fcb->RFCB.FileSize;
    Fcb->RFCB.AllocationSize = Fcb->RFCB.FileSize;

    CcInitializeCacheMap(DeviceExt->FATFileObject,
                         (PCC_FILE_SIZES)(&Fcb->RFCB.AllocationSize),
                         TRUE,
                         &VfatGlobalData->CacheMgrCallbacks,
                         Fcb);

    DeviceExt->LastAvailableCluster = 2;
    ExInitializeResourceLite(&DeviceExt->FatResource);

    InitializeListHead(&DeviceExt->FcbListHead);

    VolumeFcb = vfatNewFCB(DeviceExt, &VolumeNameU);
    if (VolumeFcb == NULL)
    {
        Status = STATUS_INSUFFICIENT_RESOURCES;
        goto ByeBye;
    }

    VolumeFcb->Flags = FCB_IS_VOLUME;
    VolumeFcb->RFCB.FileSize.QuadPart = DeviceExt->FatInfo.Sectors * DeviceExt->FatInfo.BytesPerSector;
    VolumeFcb->RFCB.ValidDataLength = VolumeFcb->RFCB.FileSize;
    VolumeFcb->RFCB.AllocationSize = VolumeFcb->RFCB.FileSize;
    DeviceExt->VolumeFcb = VolumeFcb;

    ExAcquireResourceExclusiveLite(&VfatGlobalData->VolumeListLock, TRUE);
    InsertHeadList(&VfatGlobalData->VolumeListHead, &DeviceExt->VolumeListEntry);
    ExReleaseResourceLite(&VfatGlobalData->VolumeListLock);

    /* read serial number */
    DeviceObject->Vpb->SerialNumber = DeviceExt->FatInfo.VolumeID;

    /* read volume label */
    ReadVolumeLabel(DeviceExt,  DeviceObject->Vpb);

    /* read clean shutdown bit status */
    Status = GetNextCluster(DeviceExt, 1, &eocMark);
    if (NT_SUCCESS(Status))
    {
        if (eocMark & DeviceExt->CleanShutBitMask)
        {
            /* unset clean shutdown bit */
            eocMark &= ~DeviceExt->CleanShutBitMask;
            WriteCluster(DeviceExt, 1, eocMark);
            VolumeFcb->Flags |= VCB_CLEAR_DIRTY;
        }
    }

    VolumeFcb->Flags |= VCB_IS_DIRTY;

    FsRtlNotifyVolumeEvent(DeviceExt->FATFileObject, FSRTL_VOLUME_MOUNT);
    FsRtlNotifyInitializeSync(&DeviceExt->NotifySync);
    InitializeListHead(&DeviceExt->NotifyList);

    Status = STATUS_SUCCESS;

ByeBye:
    if (!NT_SUCCESS(Status))
    {
        /* Cleanup */
        if (DeviceExt && DeviceExt->FATFileObject)
            ObDereferenceObject (DeviceExt->FATFileObject);
        if (Fcb)
            vfatDestroyFCB(Fcb);
        if (Ccb)
            vfatDestroyCCB(Ccb);
        if (DeviceObject)
            IoDeleteDevice(DeviceObject);
    }

    return Status;
}


/*
 * FUNCTION: Verify the filesystem
 */
static
NTSTATUS
VfatVerify(
    PVFAT_IRP_CONTEXT IrpContext)
{
    PDEVICE_OBJECT DeviceToVerify;
    NTSTATUS Status = STATUS_SUCCESS;
    FATINFO FatInfo;
    BOOLEAN RecognizedFS;
    PDEVICE_EXTENSION DeviceExt = IrpContext->DeviceExt;

    DPRINT("VfatVerify(IrpContext %p)\n", IrpContext);

    DeviceToVerify = IrpContext->Stack->Parameters.VerifyVolume.DeviceObject;
    Status = VfatBlockDeviceIoControl(DeviceToVerify,
                                      IOCTL_DISK_CHECK_VERIFY,
                                      NULL,
                                      0,
                                      NULL,
                                      0,
                                      TRUE);
    DeviceToVerify->Flags &= ~DO_VERIFY_VOLUME;
    if (!NT_SUCCESS(Status) && Status != STATUS_VERIFY_REQUIRED)
    {
        DPRINT("VfatBlockDeviceIoControl() failed (Status %lx)\n", Status);
        Status = STATUS_WRONG_VOLUME;
    }
    else
    {
        Status = VfatHasFileSystem(DeviceToVerify, &RecognizedFS, &FatInfo);
        if (!NT_SUCCESS(Status) || RecognizedFS == FALSE)
        {
            Status = STATUS_WRONG_VOLUME;
        }
        else if (sizeof(FATINFO) == RtlCompareMemory(&FatInfo, &DeviceExt->FatInfo, sizeof(FATINFO)))
        {
            /*
             * FIXME:
             *   Preformated floppy disks have very often a serial number of 0000:0000.
             *   We should calculate a crc sum over the sectors from the root directory as secondary volume number.
             *   Each write to the root directory must update this crc sum.
             */
        }
        else
        {
            Status = STATUS_WRONG_VOLUME;
        }
    }

    return Status;
}


static
NTSTATUS
VfatGetVolumeBitmap(
    PVFAT_IRP_CONTEXT IrpContext)
{
    DPRINT("VfatGetVolumeBitmap (IrpContext %p)\n", IrpContext);
    return STATUS_INVALID_DEVICE_REQUEST;
}


static
NTSTATUS
VfatGetRetrievalPointers(
    PVFAT_IRP_CONTEXT IrpContext)
{
    PIO_STACK_LOCATION Stack;
    LARGE_INTEGER Vcn;
    PRETRIEVAL_POINTERS_BUFFER RetrievalPointers;
    PFILE_OBJECT FileObject;
    ULONG MaxExtentCount;
    PVFATFCB Fcb;
    PDEVICE_EXTENSION DeviceExt;
    ULONG FirstCluster;
    ULONG CurrentCluster;
    ULONG LastCluster;
    NTSTATUS Status;

    DPRINT("VfatGetRetrievalPointers(IrpContext %p)\n", IrpContext);

    DeviceExt = IrpContext->DeviceExt;
    FileObject = IrpContext->FileObject;
    Stack = IrpContext->Stack;
    if (Stack->Parameters.DeviceIoControl.InputBufferLength < sizeof(STARTING_VCN_INPUT_BUFFER) ||
        Stack->Parameters.DeviceIoControl.Type3InputBuffer == NULL)
    {
        return STATUS_INVALID_PARAMETER;
    }

    if (IrpContext->Irp->UserBuffer == NULL ||
        Stack->Parameters.DeviceIoControl.OutputBufferLength < sizeof(RETRIEVAL_POINTERS_BUFFER))
    {
        return STATUS_BUFFER_TOO_SMALL;
    }

    Fcb = FileObject->FsContext;

    ExAcquireResourceSharedLite(&Fcb->MainResource, TRUE);

    Vcn = ((PSTARTING_VCN_INPUT_BUFFER)Stack->Parameters.DeviceIoControl.Type3InputBuffer)->StartingVcn;
    RetrievalPointers = IrpContext->Irp->UserBuffer;

    MaxExtentCount = ((Stack->Parameters.DeviceIoControl.OutputBufferLength - sizeof(RetrievalPointers->ExtentCount) - sizeof(RetrievalPointers->StartingVcn)) / sizeof(RetrievalPointers->Extents[0]));

    if (Vcn.QuadPart >= Fcb->RFCB.AllocationSize.QuadPart / DeviceExt->FatInfo.BytesPerCluster)
    {
        Status = STATUS_INVALID_PARAMETER;
        goto ByeBye;
    }

    CurrentCluster = FirstCluster = vfatDirEntryGetFirstCluster(DeviceExt, &Fcb->entry);
    Status = OffsetToCluster(DeviceExt, FirstCluster,
                             Vcn.u.LowPart * DeviceExt->FatInfo.BytesPerCluster,
                             &CurrentCluster, FALSE);
    if (!NT_SUCCESS(Status))
    {
        goto ByeBye;
    }

    RetrievalPointers->StartingVcn = Vcn;
    RetrievalPointers->ExtentCount = 0;
    RetrievalPointers->Extents[0].Lcn.u.HighPart = 0;
    RetrievalPointers->Extents[0].Lcn.u.LowPart = CurrentCluster - 2;
    LastCluster = 0;
    while (CurrentCluster != 0xffffffff && RetrievalPointers->ExtentCount < MaxExtentCount)
    {
        LastCluster = CurrentCluster;
        Status = NextCluster(DeviceExt, CurrentCluster, &CurrentCluster, FALSE);
        Vcn.QuadPart++;
        if (!NT_SUCCESS(Status))
        {
            goto ByeBye;
        }

        if (LastCluster + 1 != CurrentCluster)
        {
            RetrievalPointers->Extents[RetrievalPointers->ExtentCount].NextVcn = Vcn;
            RetrievalPointers->ExtentCount++;
            if (RetrievalPointers->ExtentCount < MaxExtentCount)
            {
                RetrievalPointers->Extents[RetrievalPointers->ExtentCount].Lcn.u.HighPart = 0;
                RetrievalPointers->Extents[RetrievalPointers->ExtentCount].Lcn.u.LowPart = CurrentCluster - 2;
            }
        }
    }

    IrpContext->Irp->IoStatus.Information = sizeof(RETRIEVAL_POINTERS_BUFFER) + (sizeof(RetrievalPointers->Extents[0]) * (RetrievalPointers->ExtentCount - 1));
    Status = STATUS_SUCCESS;

ByeBye:
    ExReleaseResourceLite(&Fcb->MainResource);

    return Status;
}

static
NTSTATUS
VfatMoveFile(
    PVFAT_IRP_CONTEXT IrpContext)
{
    DPRINT("VfatMoveFile(IrpContext %p)\n", IrpContext);
    return STATUS_INVALID_DEVICE_REQUEST;
}

static
NTSTATUS
VfatIsVolumeDirty(
    PVFAT_IRP_CONTEXT IrpContext)
{
    PULONG Flags;

    DPRINT("VfatIsVolumeDirty(IrpContext %p)\n", IrpContext);

    if (IrpContext->Stack->Parameters.FileSystemControl.OutputBufferLength != sizeof(ULONG))
        return STATUS_INVALID_BUFFER_SIZE;
    else if (!IrpContext->Irp->AssociatedIrp.SystemBuffer)
        return STATUS_INVALID_USER_BUFFER;

    Flags = (PULONG)IrpContext->Irp->AssociatedIrp.SystemBuffer;
    *Flags = 0;

    if ((IrpContext->DeviceExt->VolumeFcb->Flags & VCB_IS_DIRTY) &&
        !(IrpContext->DeviceExt->VolumeFcb->Flags & VCB_CLEAR_DIRTY))
    {
        *Flags |= VOLUME_IS_DIRTY;
    }

    return STATUS_SUCCESS;
}

static
NTSTATUS
VfatMarkVolumeDirty(
    PVFAT_IRP_CONTEXT IrpContext)
{
    ULONG eocMark;
    PDEVICE_EXTENSION DeviceExt;
    NTSTATUS Status = STATUS_SUCCESS;

    DPRINT("VfatMarkVolumeDirty(IrpContext %p)\n", IrpContext);
    DeviceExt = IrpContext->DeviceExt;

    if (!(DeviceExt->VolumeFcb->Flags & VCB_IS_DIRTY))
    {
        Status = GetNextCluster(DeviceExt, 1, &eocMark);
        if (NT_SUCCESS(Status))
        {
            /* unset clean shutdown bit */
            eocMark &= ~DeviceExt->CleanShutBitMask;
            Status = WriteCluster(DeviceExt, 1, eocMark);
        }
    }

    DeviceExt->VolumeFcb->Flags &= ~VCB_CLEAR_DIRTY;

    return Status;
}

/*
 * FUNCTION: File system control
 */
NTSTATUS
VfatFileSystemControl(
    PVFAT_IRP_CONTEXT IrpContext)
{
    NTSTATUS Status;

    DPRINT("VfatFileSystemControl(IrpContext %p)\n", IrpContext);

    ASSERT(IrpContext);
    ASSERT(IrpContext->Irp);
    ASSERT(IrpContext->Stack);

    IrpContext->Irp->IoStatus.Information = 0;

    switch (IrpContext->MinorFunction)
    {
        case IRP_MN_KERNEL_CALL:
        case IRP_MN_USER_FS_REQUEST:
            switch(IrpContext->Stack->Parameters.DeviceIoControl.IoControlCode)
            {
                case FSCTL_GET_VOLUME_BITMAP:
                    Status = VfatGetVolumeBitmap(IrpContext);
                    break;

                case FSCTL_GET_RETRIEVAL_POINTERS:
                    Status = VfatGetRetrievalPointers(IrpContext);
                    break;

                case FSCTL_MOVE_FILE:
                    Status = VfatMoveFile(IrpContext);
                    break;

                case FSCTL_IS_VOLUME_DIRTY:
                    Status = VfatIsVolumeDirty(IrpContext);
                    break;

                case FSCTL_MARK_VOLUME_DIRTY:
                    Status = VfatMarkVolumeDirty(IrpContext);
                    break;

                default:
                    Status = STATUS_INVALID_DEVICE_REQUEST;
            }
            break;

        case IRP_MN_MOUNT_VOLUME:
            Status = VfatMount(IrpContext);
            break;

        case IRP_MN_VERIFY_VOLUME:
            DPRINT("VFATFS: IRP_MN_VERIFY_VOLUME\n");
            Status = VfatVerify(IrpContext);
            break;

        default:
            DPRINT("VFAT FSC: MinorFunction %u\n", IrpContext->MinorFunction);
            Status = STATUS_INVALID_DEVICE_REQUEST;
            break;
    }

    IrpContext->Irp->IoStatus.Status = Status;

    IoCompleteRequest(IrpContext->Irp, IO_NO_INCREMENT);
    VfatFreeIrpContext(IrpContext);
    return Status;
}