CRFS source and project resources are now available

[Zach Brown <zach.brown@oracle.com>]

Hello everyone,

Back at this year's LCA I gave a talk introducing CRFS, a cache coherent
networked file system.

  http://linux.conf.au/programme/detail?TalkID=247
  http://mirror.linux.org.au/pub/linux.conf.au/2008/Fri/mel8-247.ogg

At the time of the talk the source wasn't available.  It's now available
in a mercurial repository, along with the usual set of mailing lists, at:

  http://oss.oracle.com/projects/crfs/

The project is still early alpha which is why I'm only sending this
initial mail to -fsdevel.  In the coming months it should stabilize and
be more suitable for wider experimentation.  Now is the time to get
involved if you want to get your hands dirty in the initial design and
implementation.

I think the video recording of the talk does a decent job of giving an
overview of the design, and it's a hoot, but I can give a quick summary:

 - the user space server exports a private BTRFS volume
 - the network protocol operates on ranges of BTRFS disk items
 - the kernel client provides posix semantics by operating on items
 - the server can grant and revoke client caches of data and metadata

There's a lot of complexity hiding in those four lines but those are the
critical properties to grasp :).

The implementation has barely covered communicating item ranges between
the server and the client.  A single client can perform simple metadata
and data read and write operations.  Anything more complicated falls
over pretty quickly.  It's enough scaffolding to support divergent
concurrent development, though.

So, if this stuff interests you, do give it a try or share your thoughts
over on the crfs- mailing lists.

- z