Subject: [nfsv4] Linux pNFS Implementation Available

From: Dean Hildebrand <[email-masked]>
Date: Tue, 26 Apr 2005 12:35:38 -0400 (EDT)

Hi All,

To those who are interested, I have released the source code of my pNFS
implementation on Linux 2.6.12-rc2.  With PVFS2 I only used the LAYOUTGET
operation, so the remaining operations are untested (more details below).
The arguments for each operation are a "best guess", and for some I simply
didn't even try as the operations specification needs a lot of work.  My
goal is to get people using and completing the implementation of the pNFS
operations.

>From talking with Andy and Bruce here at CITI, it seems the biggest hurdle
in the operation specification is state management.  What is a layout
stateid?  Does it have its own sequence number or does it follow with the
OPEN stateid?  There are many more questions and we are slowly grappling
with them.  Hopefully, we can send out some more details for each
operation soon.  For now, my implementation attaches a layout to the open
stateid.

The source includes:
-LAYOUTGET operation (fully tested).
-Preliminary implementations of LAYOUTCOMMIT and LAYOUTRETURN. Export
functions for the underlying file system have been created. Each supports
a best guess of operation arguments. None are executed in current I/O
flow.
-Stub functions and some XDR for the GETDEVICEINFO, GETDEVICELIST and
CB_LAYOUTRECALL operations. Where will the device info actually come from?
Will the NFSv4 server have this knowledge or the underlying file system?
(I'm guess the underlying file system of course) Each supports a best
guess of operation arguments. None are executed in current I/O flow.
-File system attribute to determine correct layout driver.
-Fully NFSv4/NFSv3/NFSv2 backward compatible.
-Layout driver registration mechanism.
-Initial layout driver interface (see paper below).
-A preliminary layout cache on the pNFS client.
-Currently NO caching is supported for pNFS clients utilizing a layout
driver for I/O.
-Currently, the open stateid is used for the layout. A layout stateid is
in the list of things to come.

Please use at your own risk.  Feedback is very welcome.
Dean

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From: Dean Hildebrand <[email-masked]>
Date: Tue, 26 Apr 2005 12:41:14 -0400 (EDT)

As always, I forgot the link,
http://www.citi.umich.edu/projects/asci/index.html

Dean Hildebrand
PhD Candidate
University of Michigan