FSCTL_SET_COMPRESSION

NTFSD
1

Where is the buffer for this call located? From mear testing, I’d
guess Irp->AssociatedIrp.SystemBuffer. In Fat, though it checks if the
buffer is NULL or not - if it isn’t it’s used as the buffer, otherwise
Irp->MdlAddress is used. (Not for this, but another FSCTL code).
Should it be checked this way? System then Mdl buffer? For a
USHORT???

–
Kind regards, Dejan M. www.alfasp.com
E-mail: xxxxx@alfasp.com
Alfa Transparent File Encryptor - Transparent file encryption services.
Alfa File Protector - File protection and hiding library for Win32
developers.
Alfa File Monitor - File monitoring library for Win32 developers.

2

FSCTL_SET_COMPRESSION is defined with METHOD_BUFFERED, so therefore the
buffer always has to be in pIrp->AssociatedIrp.SystemBuffer (according
to the XP IFSKIT docs on IRP_MJ_FILE_SYSTEM_CONTROL).

  • Nicholas Ryan

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Dejan Maksimovic
Sent: Friday, February 28, 2003 10:43 AM
To: File Systems Developers
Subject: [ntfsd] FSCTL_SET_COMPRESSION

Where is the buffer for this call located? From mear
testing, I’d guess Irp->AssociatedIrp.SystemBuffer. In Fat,
though it checks if the buffer is NULL or not - if it isn’t
it’s used as the buffer, otherwise
Irp->MdlAddress is used. (Not for this, but another FSCTL code).
Should it be checked this way? System then Mdl buffer?
For a USHORT???

–
Kind regards, Dejan M. www.alfasp.com
E-mail: xxxxx@alfasp.com
Alfa Transparent File Encryptor - Transparent file encryption
services. Alfa File Protector - File protection and hiding
library for Win32 developers. Alfa File Monitor - File
monitoring library for Win32 developers.

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

3

> FSCTL_SET_COMPRESSION is defined with METHOD_BUFFERED, so therefore the

I didn’t think of that, thanks:-)

–
Kind regards, Dejan M. www.alfasp.com
E-mail: xxxxx@alfasp.com
Alfa Transparent File Encryptor - Transparent file encryption services.
Alfa File Protector - File protection and hiding library for Win32
developers.
Alfa File Monitor - File monitoring library for Win32 developers.