Re: Filtering disk IO when Windows hibernates

On 23 Dec 2005 02:11:47 -0800, ser-news@xxxxxxxxxxxx wrote:

You have a major task in front of you. As you have observed, the
hibernate/dump path uses separate copies of the storage stack for the
'dump path' drivers. Normal filtering is pretty much out of the
question. Also the whole dump driver subsystem is totally
undocumented by Microsoft. However - this has been discussed in quite
some detail over on the ntdev email list (goto osronline.com to sign
up.) You should search that list for details.

Eventually you will come to the conclusion that you need your own hba
miniport - probably not the answer you wanted to hear - or you are
going to have to walk way outside the box to get some sort of filter
wedged into the dump path.

>Dear gurus,
>
>Could you advise how disk IO requests Windows 2000/XP sends during
>hibernate (or
>crash file dump) process can be filtered?
>
>In more detail, the problem is in the following. We work on software
>that transparently
>encrypts sectors on physical disks. My disk IO filtering driver works
>fine except the moment
>when Windows hibernates or writes crash dump file to disk. At that
>moment Windows does
>not use a regular well-documented stack of layered disk drivers.
>Instead, the operating system
>calls disk miniport driver directly. (Probably it would be more
>correctly to say - after sending IOCTL_SCSI_GET_DUMP_POINTERS Windows
>loads a separate copy of the driver and uses
>it for writing sectors.)
>
>As a result, our filtering driver cannot filter and encrypt the sectors
>Windows writes during the
>hibernation process.
>
>If someone knows how to filter these disk IO requests, the advice
>would be greately appreciated.
>
>Best regards,
>Sergey
>
>(I've read several topics on the matter in newsgroups, but could not
>find some concrete answer.
>As MSDN subscribers probably we should contact Microsoft, but is it
>really necessary and may
>help?)
=====================
Mark Roddy DDK MVP
Windows Vista/2003/XP/2000 Consulting
Device and Filesystem Drivers
Hollis Technology Solutions 603-321-1032
www.hollistech.com
.

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