Do you mean in the completion routine? If so, what if you need to perform
some operations that *must* be perfomed at passive level? The completion
routine could get invoked at dispatch level.
Marc
-----Original Message-----
From: Jamey Kirby [mailto:xxxxx@storagecraft.com]
Sent: Wednesday, July 19, 2000 1:19 PM
To: File Systems Developers
Subject: [ntfsd] RE: preventing recursive loop in create dispatch hand
lerAlso, I am trying to understand the need to open a file via
an alternate IRP
in a creation routine. If you are getting an IRP_MJ_CREATE
and the file is,
say, “c:\x.x”, why would anyone create a seperate file
object, build a new
IRP and open the file “c:\x.x”? WOuld it not be better to
simply let the
original IRP_MJ_CREATE go through and then perform some
operation on the
file after completion?Am I missing something?
Jamey
> -----Original Message-----
> From: xxxxx@lists.osr.com
> [mailto:xxxxx@lists.osr.com]On Behalf Of Pavel Hrdina
> Sent: Wednesday, July 19, 2000 9:51 AM
> To: File Systems Developers
> Subject: [ntfsd] RE: preventing recursive loop in create
dispatch hand
> ler
>
>
> I think the Geoff Clow is nearest to the TRUTH.
> It is neccessary to disassemble some parts of NTOS to
> definitely understand some interactions between components.
>
> I have used the following techniques:
>
> 1. I am using no Io Manager’s and Memory Manager’s ZwXxxx routines
> inside the FSD filter. I use them only from some system
thread where
> I know I’m the Request Iniciator (mostly in Nt variant,
> because there is
> evident the Thread->PreviousMode is KernelMode and thus
the mechanism
> for system calls [int 2e] is not needed at all).
>
> 2. For every mounted volume there is in our VCB:
>
> a) Physical device (named, eg. \Device\Harddisk0\Partition5)
> b) FSD device (mostly unnamed)
> c) Next lower device
>
> - to NextLowerDevice we will forward all requests
> - if we are attached right to FSD device, these two will
be the same
> - for network redirectors the Physical device and FSD device
> are the same
> eg. \Device\LanmanRedirector
>
> 3. If I want to open the file, query or set some info on it:
>
> I have written some synchronous routines like a NtCreateFile,
> NtQueryInformationFile and NtSetInformation file. Each of
> it builds an IRP and sends it down to the Vcb->NextLowerDevice.
> Thus I’m always calling all the filter stack below me, but no
> filter above me gets called.
>
> I am appending the file APISUP.C which contains these routines and
> mechanisms I’m using. (Hardest routine to implement is Create and
> currently I know some of its disadvantages - base methods are taken
> from the IopParseDevice routine)
>
> Paul
>
> > <<apisup.c>>
> >
> >
>
>
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></apisup.c>