problem with direct writes to volume

NTDEV
1

Hi all,

Is it possible to write to disk/boot partition directly when volume is locked?
I have volume upper filter driver.
I want to write to file on boot partition when volume is locked.
To do so, i can call ZwFsControlFile with control code FSCTL_GET_RETRIVAL_POINTER to retrive the allocation and location on disk of a specific file.

But the problem is that, there is no documentation about how to use vcn and lcn fields return by function.
No idea how i can progress on this front!!!

Which area of boot partition can be accessible when that volume/partition is locked?
I just want to write a flag to volume.

Thanks in anticipation!

2

http://www.wd-3.com/archive/luserland.htm

I cover the basics in this article. By the way, crossposting to both of
these lists is considered bad form.

On Tue, Feb 26, 2008 at 8:31 AM, wrote:

> Hi all,
>
> Is it possible to write to disk/boot partition directly when volume is
> locked?
> I have volume upper filter driver.
> I want to write to file on boot partition when volume is locked.
> To do so, i can call ZwFsControlFile with control code
> FSCTL_GET_RETRIVAL_POINTER to retrive the allocation and location on disk of
> a specific file.
>
> But the problem is that, there is no documentation about how to use vcn
> and lcn fields return by function.
> No idea how i can progress on this front!!!
>
> Which area of boot partition can be accessible when that volume/partition
> is locked?
> I just want to write a flag to volume.
>
> Thanks in anticipation!
>
>
>
> —
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–
Mark Roddy

3

Thanks Mark…
Actually i was not sure whether this should be placed on ntfsd or on ntdev. Question was in mixed form. sorry for the same.

4

How we can write to file using vcn and lcn?

5

Hi mark,

>>> I cover the basics in this article.
In your article you have not covered write part (i.e. write to file using vcn and lcn).
Can you elaborate on the same?

Thanks in anticipation!!!