In the past, readdir assumed that the user buffer will be large enough
that all entries from the server will fit.  If this was not true,
entries would be skipped.

Since it works now, request 512 entries rather than 96 per server
operation.
Signed-off-by: NMartin Brandenburg <martin@omnibond.com>
Signed-off-by: NMike Marshall <hubcap@omnibond.com>

This is a new userspace operation, which will be done if the client-core
version is greater than or equal to 2.9.6. This will provide a way to
implement optional features and to determine which features are
supported by the client-core. If the client-core version is older than
2.9.6, no optional features are supported and the op will not be done.

The intent is to allow protocol extensions without relying on the
client-core's current behavior of ignoring what it doesn't understand.
Signed-off-by: NMartin Brandenburg <martin@omnibond.com>

This will support a upcoming request where two related values need to be
updated atomically.

This was done without a union in the OrangeFS server source already. Since
that will break the kernel protocol, it has been fixed there and done here
in a way that does not break the kernel protocol.
Signed-off-by: NMartin Brandenburg <martin@omnibond.com>

Signed-off-by: NMartin Brandenburg <martin@omnibond.com>
Signed-off-by: NMike Marshall <hubcap@omnibond.com>

OrangeFS was formerly known as PVFS2 and retains the name in many places.

I leave the device /dev/pvfs2-req since this affects userspace.

I leave the filesystem type pvfs2 since this affects userspace. Further
the OrangeFS sysint library reads fstab for an entry of type pvfs2
independently of kernel mounts.

I leave extended attribute keys user.pvfs2 and system.pvfs2 as the
sysint library understands these.

I leave references to userspace binaries still named pvfs2.

I leave the filenames.
Signed-off-by: NYi Liu <yi9@clemson.edu>
[martin@omnibond.com: clairify above constraints and merge]
Signed-off-by: NMartin Brandenburg <martin@omnibond.com>
Signed-off-by: NMike Marshall <hubcap@omnibond.com>

Also removes remnants of iox (readx/writex) which previously used
trailers, but no longer exist.
Signed-off-by: NMartin Brandenburg <martin@omnibond.com>
Signed-off-by: NMike Marshall <hubcap@omnibond.com>

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

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: NMike Marshall <hubcap@omnibond.com>