remove file objects

NTFSD
1

hi,

i am using ObCreateObject to create file objects so that i can access files
in my FSFD.

i am now using ObDereferenceObject to remove them after use. is this the
correct way?

the scenario i am seeing is that the system slows down a lot after scanning
the system with NAV. and checking the memory pool use, the tag FILE is used
the most. so i presume this represents file objects.

Ampsi

2

I wouldn’t create them in this way - there are APIs available
specifically for the creation of temporary file objects:

IoCreateStreamFileObject/IoCreateStreamFileObjectLite

  • Nicholas Ryan

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Ampsi
Sent: Friday, April 18, 2003 1:17 AM
To: File Systems Developers
Subject: [ntfsd] remove file objects

hi,

i am using ObCreateObject to create file objects so that i
can access files in my FSFD.

i am now using ObDereferenceObject to remove them after use.
is this the correct way?

the scenario i am seeing is that the system slows down a lot
after scanning the system with NAV. and checking the memory
pool use, the tag FILE is used the most. so i presume this
represents file objects.

Ampsi

You are currently subscribed to ntfsd as: xxxxx@nryan.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

3

in a create request for a file, can i use the APIs to open the file with the
file object in the stack location prior sending the irp to the fsd?

in the same request, how can i use the APIs to open the directory for the
file?

i would also like to open files in directory control, can i achieve this
with the APIs?

thanks!

Ampsi

----- Original Message -----
From: “Nicholas Ryan”
To: “File Systems Developers”
Sent: Friday, April 18, 2003 4:54 PM
Subject: [ntfsd] RE: remove file objects

I wouldn’t create them in this way - there are APIs available
specifically for the creation of temporary file objects:

IoCreateStreamFileObject/IoCreateStreamFileObjectLite

- Nicholas Ryan

> -----Original Message-----
> From: xxxxx@lists.osr.com
> [mailto:xxxxx@lists.osr.com] On Behalf Of Ampsi
> Sent: Friday, April 18, 2003 1:17 AM
> To: File Systems Developers
> Subject: [ntfsd] remove file objects
>
>
> hi,
>
> i am using ObCreateObject to create file objects so that i
> can access files in my FSFD.
>
> i am now using ObDereferenceObject to remove them after use.
> is this the correct way?
>
> the scenario i am seeing is that the system slows down a lot
> after scanning the system with NAV. and checking the memory
> pool use, the tag FILE is used the most. so i presume this
> represents file objects.
>
> Ampsi
>
>
>
>
> —
> You are currently subscribed to ntfsd as: xxxxx@nryan.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com
>

—
You are currently subscribed to ntfsd as: xxxxx@pmail.ntu.edu.sg
To unsubscribe send a blank email to xxxxx@lists.osr.com

4

If you’re talking about sending down an IRP_MJ_CREATE IRP with your OWN
file object attached (one that you created), I recommend against this.
Most on the group consider this to be a very risky technique. You can
always open a file (or a directory) with ZwCreateFile at any time as
long as you’re at passive level. If you’re worried about re-entrancy
into your filter’s create path, there are solutions that don’t involve
creating your own file object. See the OSR IFS faq at www.osr.com.

  • Nicholas Ryan

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Ampsi
Sent: Saturday, April 19, 2003 12:35 AM
To: File Systems Developers
Subject: [ntfsd] RE: remove file objects

in a create request for a file, can i use the APIs to open
the file with the file object in the stack location prior
sending the irp to the fsd?

in the same request, how can i use the APIs to open the
directory for the file?

i would also like to open files in directory control, can i
achieve this with the APIs?

thanks!

Ampsi

----- Original Message -----
From: “Nicholas Ryan”
> To: “File Systems Developers”
> Sent: Friday, April 18, 2003 4:54 PM
> Subject: [ntfsd] RE: remove file objects
>
>
> I wouldn’t create them in this way - there are APIs available
> specifically for the creation of temporary file objects:
>
> IoCreateStreamFileObject/IoCreateStreamFileObjectLite
>
> - Nicholas Ryan
>
> > -----Original Message-----
> > From: xxxxx@lists.osr.com
> > [mailto:xxxxx@lists.osr.com] On Behalf Of Ampsi
> > Sent: Friday, April 18, 2003 1:17 AM
> > To: File Systems Developers
> > Subject: [ntfsd] remove file objects
> >
> >
> > hi,
> >
> > i am using ObCreateObject to create file objects so that i
> can access
> > files in my FSFD.
> >
> > i am now using ObDereferenceObject to remove them after
> use. is this
> > the correct way?
> >
> > the scenario i am seeing is that the system slows down a lot after
> > scanning the system with NAV. and checking the memory pool use, the
> > tag FILE is used the most. so i presume this represents
> file objects.
> >
> > Ampsi
> >
> >
> >
> >
> > —
> > You are currently subscribed to ntfsd as: xxxxx@nryan.com
> > To unsubscribe send a blank email to xxxxx@lists.osr.com
> >
>
>
>
> —
> You are currently subscribed to ntfsd as:
> xxxxx@pmail.ntu.edu.sg To unsubscribe send a blank email to
> xxxxx@lists.osr.com
>
>
>
>
> —
> You are currently subscribed to ntfsd as: xxxxx@nryan.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com
>