Re: Queries to understand OpenAFS as a Remote File System

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Bharat,

Jeff can do a much more detailed job answering this, but, in general,
the questions you seem to be struggling with are, "Why does OpenAFS use
SMB at all?" and, "Where is the kernel mode file system driver?"

The answer more or less is, in the OpenAFS Windows client builds
distributed today, the client does, as you found, present an SMB
interface to the Windows system, and use the AFS protocol to interface
with OpenAFS.

Work has been ongoing to replace this implementation for some time.  You
can look at the IFS build configuration in the source tree to see the
most complete work.  You would need an MS IFS kit to build it.  The IFS
client uses a standard filesystem driver implementation to communicate
with Windows about client file accesses, and a private pipe is used for
communication between the driver component and the AFS protocol client.
 This is the general future direction of OpenAFS for Windows, as I
understand it (that's what is articulated in the Roadmap), although the
IFS kit might be replaced, other architectural changes made.

Matt

Bharat Kulkarni wrote:
> Hello,
> 
> I had a few queries regarding OpenAFS Architecture and implementation.
> 
> As i went thru the code, it seems you have implemented SMB protocols in it.
> However as i read the SMB protocol, i learnt that SMB protocol firsts sends
> Negotiate packet to server, ANDX and then ConnectTree opcodes etc to
> communicate with server.. But in OpenAFS case I can see some other calls
> like the ones fed into the structure "smb_dispatchTable". Some of them
> being
> "smb_ReceiveV3Tran2A" , "smb_ReceiveNTCreateX" etc.. So I wanted to know
> how
> OpenAFS has implemented SMB protocol and on what level is it implemented.
> Also there are Netbios Function used and the NCB structures are widely
> used.
> Can you throw some light as to what roles SMB and Netbios/NCBs play in a
> distributed File system environment like OpenAFS.
> 
> Also, How does windows talk to OpenAFS client. Is it through SMB Packet and
> Netbios. SMB protocol is usually between two windows client on network.
> However, as I understand, in this case, its used when OpenAFS client wants
> to talk to Windows (when some operation is carried out in OpenAFS drive) on
> the same local machine. (When client wants to talk to server on a remote
> machine, RX RPC is used.) So how is this communication between windows and
> OpenAFS client been taken care of?
> 
> I also want to understand, How in OpenAFS, a remote Filesystem is
> implemented using SMB protocol along with filesystem Driver component in
> the
> kernel mode?
> 
> Also, as I have read in Vista docs, we now need to register with
> MUP.syswhile communicating or mapping any remote drive. Does OpenAFS
> do that. Or
> does it use Wnet API of the MPR.dll?
> 
> 
> 
> Can you kindly help me with the queries to understand the architecture of a
> Remote Filesystem.
> 
> Thanking you in anticipation.
> 
> Regards,
> 
> Bharat.
> 




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Matt Benjamin

The Linux Box
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Ann Arbor, MI  48104

http://linuxbox.com

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