NTFS - VMM routines

NTFSD
1

Hi All,

Currently i am writing a device driver code for Win NT file system - code is
still at infant stage. I just realized that the code is not calling VMM
routine while modifying ‘AllocationSize’ information (in
IRP_MJ_QUERY_INFORMATION , IRP_MJ_SET_INFORMATION) - I was wondering is call
to VMM and CC mandatory after every modification to ‘AllocationSize’ field
value? Also problem is code is divided into two parts - one runs in kernel
mode and another one in the user mode and both of them communicates with
each other using IOCTL. Most of the code is in usermode part, including the
code which handles all the interrupts (like IRP_MJ_CREATE or IRP_MJ_SET_INFO
…) - It seems that it is not possible to make a call to VMM or CC routines
from the driver running in the user mode - In fact i m having a similar
problem in making call to KeQuerySystemTime() - Was wondering if anyone has
faced the problem before.

Thanks in advance
Devang

2

Pretty much any function documented in the kernel-mode reference in the
DDK can be called only from kernel-mode. While there are similar time
functions available from usermode (either Win32 or native APIs), there
aren’t any for memory-manager or cache-manager.

Yes I believe you need to tell those subsystems when the file sizes
change with CcSetFileSizes().

Dave Cox
Hewlett-Packard Co.
HPSO/SSMO (Santa Barbara)
https://ecardfile.com/id/Dave+Cox

-----Original Message-----
From: Devang Shah [mailto:dsshah@cs.cmu.edu]
Sent: Wednesday, April 12, 2000 8:18 PM
To: File Systems Developers
Subject: [ntfsd] NTFS - VMM routines

Hi All,

Currently i am writing a device driver code for Win NT file system - code is
still at infant stage. I just realized that the code is not calling VMM
routine while modifying ‘AllocationSize’ information (in
IRP_MJ_QUERY_INFORMATION , IRP_MJ_SET_INFORMATION) - I was wondering is call
to VMM and CC mandatory after every modification to ‘AllocationSize’ field
value? Also problem is code is divided into two parts - one runs in kernel
mode and another one in the user mode and both of them communicates with
each other using IOCTL. Most of the code is in usermode part, including the
code which handles all the interrupts (like IRP_MJ_CREATE or IRP_MJ_SET_INFO
…) - It seems that it is not possible to make a call to VMM or CC routines
from the driver running in the user mode - In fact i m having a similar
problem in making call to KeQuerySystemTime() - Was wondering if anyone has
faced the problem before.

Thanks in advance
Devang

You are currently subscribed to ntfsd as: david_cox2@hp.com
To unsubscribe send a blank email to $subst(‘Email.Unsub’)