Re: IRP Create

Subject: Activity Info in IRP_CREATEs

Thank you very much for your fast and highly professional answers, Anton and
Don!

Your replies showed me 2 things: It looks like I still gotta learn a lot
more about the file system and it also showed me that my file system driver
code isn't as bad as I thought it could be.

A specific reply to you, Anton:

How is IO Manager supposed to know which particular function the client code
is about to call next while it processes ZwCreateFile() call???:

It looks like that not all the information the Win32 Subsystem knows is
shared with the IO Manager. I'm sure if the driver model could be redesigned
from scratch without regard to any compatibilty issues one of these levels
would be omitted. That's what I would do, anyway. Then the IRP_CREATE op
would indeed include the type of file operation that is going to be carried
out, so it could be manipulated (eg blocked) at that early stage if the need
arised. Are you listening, Microsoft FS driver programmers? Here is what
(some of) your customers want!

Now to your remark, Don:

"Tracking file names is hard, the examples in WDK/IFS kit show a large
amount of effort in handling these cases."

You are dead right! It was very hard indeed to track the filenames. But
after having removed a bug in the IFS Kit (CD version) things looked much
better. That bug never manifested itself in the filter sample provided but
it raised its ugly head when the FileName routines were taken from the
logging environment. It's kind of a mistake that hardly ever occurs when
professional programmers write code, rather, I have the sneaky suspicion
that this bug was implemented on purpose...


I also thougt that the IFS kit provides just the bare minimum of aid and it
is still very hard to get started. Microsoft could have done a much better
job to make this start easier, or was that also done on purpose???

Any comments welcome.

Michael Keller


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