Modifying IRPs

NTFSD
1

Hi,

Does anyone have any comments on the practice of modifying an IRP (e.g.
changing the buffer address, read/write length, etc) on the way down
and restoring it in the completion routine?

It seems to work okay, but am I opening myself up to problems under some
conditions?

Thanks.

Shaun

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2

I modify the create irp’s system buffer pointer and the corresponding length
field and then return SMPR from the completion routine so that I can restore
both in my create dispatch routine (where I know I’m running at passive
level). In my case, I’m *only* filtering the lanman redirector. I haven’t
had any problems doing this. However, I think others have mentioned problems
with this while filtering ntfs (it likes to free the buffer or something).

good luck,
Marc

-----Original Message-----
From: Shaun [mailto:xxxxx@sdlabs.demon.co.uk]
Sent: Tuesday, January 30, 2001 11:43 AM
To: File Systems Developers
Subject: [ntfsd] Modifying IRPs

Hi,

Does anyone have any comments on the practice of modifying an
IRP (e.g.
changing the buffer address, read/write length, etc) on the way down
and restoring it in the completion routine?

It seems to work okay, but am I opening myself up to problems
under some
conditions?

Thanks.

Shaun

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