IRP_MJ_READ with IRP_MN_MDL

NTFSD
1

Hi All,

Is there a way for a mini-filter to tell to the SRV driver that
IRP_MJ_READ/IRP_MN_MDL operations are not supported so that the SRV will use
a read buffer instead? Performance penalty is not important in this case.

Thanks,
Roman

2

Not that I know of. What is the reason for this?

Roman Listiev wrote:

Hi All,

Is there a way for a mini-filter to tell to the SRV driver that
IRP_MJ_READ/IRP_MN_MDL operations are not supported so that the SRV will use
a read buffer instead? Performance penalty is not important in this case.

Thanks,
Roman

Questions? First check the IFS FAQ at https://www.osronline.com/article.cfm?id=17

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–
Kind regards, Dejan
http://www.alfasp.com
File system audit, security and encryption kits.

3

Hi Dejan,

Thanks for the interest.

The reason is that in some cases final read data should be a combined data
from two different files.

Regards,

-Roman

“Dejan Maksimovic” wrote in message news:xxxxx@ntfsd…
>
> Not that I know of. What is the reason for this?
>
> Roman Listiev wrote:
>
>> Hi All,
>>
>> Is there a way for a mini-filter to tell to the SRV driver that
>> IRP_MJ_READ/IRP_MN_MDL operations are not supported so that the SRV will
>> use
>> a read buffer instead? Performance penalty is not important in this case.
>>
>> Thanks,
>> Roman
>>
>> —
>> Questions? First check the IFS FAQ at
>> https://www.osronline.com/article.cfm?id=17
>>
>> You are currently subscribed to ntfsd as: xxxxx@alfasp.com
>> To unsubscribe send a blank email to xxxxx@lists.osr.com
>
> –
> Kind regards, Dejan
> http://www.alfasp.com
> File system audit, security and encryption kits.
>
>
>

4

In which case you can do it via MDLs as well, since unlike with memory mapped
files you have complete access to the data returned. You can return your own MDL.

Roman Listiev wrote:

The reason is that in some cases final read data should be a combined data from two
different files.

–
Kind regards, Dejan
http://www.alfasp.com
File system audit, security and encryption kits.

5

Thanks Dejan.

Actually I was curios because completing of such a read in my preoperation
callback routine with STATUS_NOT_SUPPORTED did not work.

Roman

“Roman Listiev” wrote in message news:xxxxx@ntfsd…
> Hi All,
>
>
>
> Is there a way for a mini-filter to tell to the SRV driver that
> IRP_MJ_READ/IRP_MN_MDL operations are not supported so that the SRV will
> use a read buffer instead? Performance penalty is not important in this
> case.
>
>
> Thanks,
> Roman
>
>