Orangefs: kernel client part 1

Orangefs: kernel client part 1

OrangeFS (formerly PVFS) is an lgpl licensed userspace networked parallel
file system. OrangeFS can be accessed through included system utilities,
user integration libraries, MPI-IO and can be used by the Hadoop
ecosystem as an alternative to the HDFS filesystem. OrangeFS is used
widely for parallel science, data analytics and engineering applications.

While applications often don't require Orangefs to be mounted into
the VFS, users do like to be able to access their files in the normal way.
The Orangefs kernel client allows Orangefs filesystems to be mounted as
a VFS. The kernel client communicates with a userspace daemon which in
turn communicates with the Orangefs server daemons that implement the
filesystem. The server daemons (there's almost always more than one)
need not be running on the same host as the kernel client.

Orangefs filesystems can also be mounted with FUSE, and we
ship code and instructions to facilitate that, but most of our users
report preferring to use our kernel module instead. Further, as an example
of a problem we can't solve with fuse, we have in the works a
not-yet-ready-for-prime-time version of a file_operations lock function
that accounts for the server daemons being distributed across more
than one running kernel.

Many people and organizations, including Clemson University,
Argonne National Laboratories and Acxiom Corporation have
helped to create what has become Orangefs over more than twenty
years. Some of the more recent contributors to the kernel client
include:

  Mike Marshall
  Christoph Hellwig
  Randy Martin
  Becky Ligon
  Walt Ligon
  Michael Moore
  Rob Ross
  Phil Carnes

Signed-off-by: Mike Marshall <hubcap@omnibond.com>