Drive letter in IRP_MJ_CREATE......

NTFSD
1

I am using sfilter from IFS windows server 2003 …

I use “IoVolumeDeviceToDosName” to get the driver letter.

the following is the function …

PUNICODE_STRING GetDriveLetter(PDEVICE_OBJECT StorageDevice)
{
NTSTATUS ntstat;

// Drive , drivebuffer is declared as global…
RtlInitEmptyUnicodeString(&Drive,drivebuffer,sizeof(drivebuffer) );

ntstat = IoVolumeDeviceToDosName( StorageDevice,&Drive);
if( STATUS_SUCCESS != ntstat )
{
DbgPrint(“\n IoVolumeDeviceToDosName Failed “);
}
else
DbgPrint(”\n DRIVE_LETTER =%wZ”,&Drive);

return &Drive;
}

I am calling the above function in IRP_MJ_CREATE dispatch …

PSFILTER_DEVICE_EXTENSION devExt = DeviceObject->DeviceExtension;

GetDriveLetter(devExt->StorageStackDeviceObject);
-…-…-…-…-.

I do not know what is wrong with my code …

It is working fine for first few IRP_MJ_CREATE but after few IRP_MJ_CREATE it hangs …
No blue screen but…
I noticed that the IoVolumeDeviceToDosName is not returning …

Any help on “what could be the problem…”…??

PRIYA MS

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2

We have discussed this problem several times to death
(If I am authorized to use Peter Viscarola’s words :-).

Please, search the archives of this list server, you will
find lots of threads dedicated to this problem.

L.

3

–

RtlInitEmptyUnicodeString is used to initialize an empty counted string,
but in your case since Drive is a global variable, you might be calling
it with the non empty string , so make sure that each time you call
RtlInitEmptyUnicodeString with “Drive” variable being empty or try using
RtlInitUnicodeString.

–
K.Raju

From: NTFSD NTDEV [mailto:xxxxx@yahoo.com]
Sent: Friday, December 03, 2004 1:30 PM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] Drive letter in IRP_MJ_CREATE…

I am using sfilter from IFS windows server 2003 …

I use “IoVolumeDeviceToDosName” to get the driver letter.

the following is the function …

PUNICODE_STRING GetDriveLetter(PDEVICE_OBJECT StorageDevice)
{
NTSTATUS ntstat;

// Drive , drivebuffer is declared as global…
RtlInitEmptyUnicodeString(&Drive,drivebuffer,sizeof(drivebuffer) );

ntstat = IoVolumeDeviceToDosName( StorageDevice,&Drive);
if( STATUS_SUCCESS != ntstat )
{
DbgPrint(“\n IoVolumeDeviceToDosName Failed “);
}
else
DbgPrint(”\n DRIVE_LETTER =%wZ”,&Drive);

return &Drive;
}

I am calling the above function in IRP_MJ_CREATE dispatch …

PSFILTER_DEVICE_EXTENSION devExt = DeviceObject->DeviceExtension;

GetDriveLetter(devExt->StorageStackDeviceObject);
-…-…-…-…
…-.

I do not know what is wrong with my code …

It is working fine for first few IRP_MJ_CREATE but after few
IRP_MJ_CREATE it hangs …
No blue screen but…
I noticed that the IoVolumeDeviceToDosName is not returning …

Any help on “what could be the problem…”…??

PRIYA MS

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