IRP_MJ_READs and WRITES sent by NTFS formatting

NTFSD
1

I am writing an encrypted disk driver that mounts a file as a FILE_DEVICE_DISK
and intercepts all IRP_MJ_READ and IRP_MJ_WRITE buffers and encrypts and
decrypts them accordingly. When I format the volume, the system will write a
sector then read it for the first 32K of the disk, then it will, seemingly,
jump all over the place with reads and writes of varying sizes. Unfortunately
my driver will fail upon the first of these. While I will not fully discount an
error in my encryption mechanism, I have spent several hours trying to find a
problem with it and can’t. So I am wondering if anybody has any insight as to
how exactly the NTFS formatting works and if there is anything extra I might
need to take into account. I am formatting by using the standard format
function when you right-click on the drive. Thank you in advance for any help
anyone can offer.

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2

> When I format the volume, the system will write a

sector then read it for the first 32K of the disk, then it will,
seemingly,
jump all over the place with reads and writes of varying sizes.

Thats what I’d expect it to do

Unfortunately
my driver will fail upon the first of these.

Fail how? We need more information to be able to help…

/rod

3

Formatting usually fails due to mis-responding to the volume size queries.

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com

----- Original Message -----
From:
To: “Windows File Systems Devs Interest List”
Sent: Saturday, August 06, 2005 11:22 AM
Subject: [ntfsd] IRP_MJ_READs and WRITES sent by NTFS formatting

> I am writing an encrypted disk driver that mounts a file as a
FILE_DEVICE_DISK
> and intercepts all IRP_MJ_READ and IRP_MJ_WRITE buffers and encrypts and
> decrypts them accordingly. When I format the volume, the system will write a
> sector then read it for the first 32K of the disk, then it will, seemingly,
> jump all over the place with reads and writes of varying sizes. Unfortunately
> my driver will fail upon the first of these. While I will not fully discount
an
> error in my encryption mechanism, I have spent several hours trying to find a
> problem with it and can’t. So I am wondering if anybody has any insight as to
> how exactly the NTFS formatting works and if there is anything extra I might
> need to take into account. I am formatting by using the standard format
> function when you right-click on the drive. Thank you in advance for any help
> anyone can offer.
>
> ----------------------------------------------------------------
> This message was sent using IMP, the Internet Messaging Program.
>
>
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