IOCTL_LMR_DISABLE_LOCAL_BUFFERING has no effects on Win10

From vista,there are a new FSCTL:IOCTL_LMR_DISABLE_LOCAL_BUFFERING.
I use it for disable local buffering in remote file.
status=FltFsControlFile(pInstance,pFileObject,IOCTL_LMR_DISABLE_LOCAL_BUFFERING,
NULL,0,NULL,0,&retlen);
when the status==STATUS_SUCCESS,I know the client-side buffering is disabled on the remote file.
If the status is error,I will do oplock-break for the same purpose.

But in win10…
the IOCTL_LMR_DISABLE_LOCAL_BUFFERING will return STATUS_SUCCESS,but the client-side buffering is still on.
who know it?
The IOCTL_LMR_DISABLE_LOCAL_BUFFERING is no effects in win10?

Could it be that it is disabled but cleanup is happening differently on
Windows 10? How are you validating that caching is enabled on the file?

Note that this only disabled local caching while the current handle and
any actively open handles are open. Once the handles are all closed and
the redirector tears down internal structures, this state is no longer
enforced for the file. Also, if caching has already been established for
the file, IIRC it implements a pass-through mode for write processing.

Pete


Kernel Drivers
Windows File System and Device Driver Consulting
www.KernelDrivers.com
866.263.9295

------ Original Message ------
From: “xxxxx@hotmail.com
To: “Windows File Systems Devs Interest List”
Sent: 12/21/2017 12:40:31 PM
Subject: [ntfsd] IOCTL_LMR_DISABLE_LOCAL_BUFFERING has no effects on
Win10

>From vista,there are a new FSCTL:IOCTL_LMR_DISABLE_LOCAL_BUFFERING.
>I use it for disable local buffering in remote file.
>status=FltFsControlFile(pInstance,pFileObject,IOCTL_LMR_DISABLE_LOCAL_BUFFERING,
> NULL,0,NULL,0,&retlen);
>when the status==STATUS_SUCCESS,I know the client-side buffering is
>disabled on the remote file.
>If the status is error,I will do oplock-break for the same purpose.
>
>But in win10…
>the IOCTL_LMR_DISABLE_LOCAL_BUFFERING will return STATUS_SUCCESS,but
>the client-side buffering is still on.
>who know it?
>The IOCTL_LMR_DISABLE_LOCAL_BUFFERING is no effects in win10?
>
>—
>NTFSD is sponsored by OSR
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I observed the processing by filespy.
1.notepad.exe Create the file
2.notepad.exe write the file(nor paging write,just normal IO)
3.because 2,it issued paging read
4.notepad.exe setendoffile
5.notepad.exe setallocationinformation
6.notepad.exe write the file(paging write)
7.notepad.exe cleanup the handle in 1.

In step 1,I have IOCTL_LMR_DISABLE_LOCAL_BUFFERING.
But obviously,the client-side buffering is still ON.

In win7 client,everything is OK.