disabling memory mapped files?

NTFSD
1

This might be a silly question, but is there a way inside a driver to
disable memory mapping for applications? I.e., to force them to use the
traditional fastio route? Thanks. - Neil

2

Actually there is, but it will break a lot of very common application,
the will not work, period. Are you fine with that?
ravi

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Neil Weicher
Sent: Friday, November 11, 2005 4:35 PM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] disabling memory mapped files?

This might be a silly question, but is there a way inside a driver to
disable memory mapping for applications? I.e., to force them to use the
traditional fastio route? Thanks. - Neil

Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

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

3

Well, this is sort of a catch 22 question. You could disable the MM
interface from the FSD by ensuring that the SOP pointers for each FO is
NULL. But this will also disable the CM interface since now no cache section
can be built to represent the file in cache.

I guess you could ‘hook’ the preacquireforsectioncreate callback in the
underlying FSD and fail this request but then you would be removing the
ability to execute applications as well.

There is no ‘clean’ line one can draw with memory mapped files since 1) the
supporting MM interface; i.e. the SOP pointer, is required for CM and MM, 2)
they are quite close to files being executed …

Pete

Kernel Drivers
Windows Filesystem and Device Driver Consulting
www.KernelDrivers.com
(303)546-0300

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Neil Weicher
Sent: Friday, November 11, 2005 5:35 PM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] disabling memory mapped files?

This might be a silly question, but is there a way inside a driver to
disable memory mapping for applications? I.e., to force them to use the
traditional fastio route? Thanks. - Neil

Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

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

4

I’d like to see its affect, even if it is just a learning experience. So it
would be appreciated. Thanks.

----- Original Message -----
From: “Ravisankar Pudipeddi”
To: “Windows File Systems Devs Interest List”
Sent: Friday, November 11, 2005 7:56 PM
Subject: RE: [ntfsd] disabling memory mapped files?

Actually there is, but it will break a lot of very common application,
the will not work, period. Are you fine with that?
ravi

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Neil Weicher
Sent: Friday, November 11, 2005 4:35 PM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] disabling memory mapped files?

This might be a silly question, but is there a way inside a driver to
disable memory mapping for applications? I.e., to force them to use the
traditional fastio route? Thanks. - Neil

—
Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

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

—
Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

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