Add a new procfile that will allow a (privileged) userland process to
end the NLM grace period early. The basic idea here will be to have
sm-notify write to this file, if it sent out no NOTIFY requests when
it runs. In that situation, we can generally expect that there will be
no reclaim requests so the grace period can be lifted early.
Signed-off-by: NJeff Layton <jlayton@primarydata.com>

Currently, all of the grace period handling is part of lockd. Eventually
though we'd like to be able to build v4-only servers, at which point
we'll need to put all of this elsewhere.

Move the code itself into fs/nfs_common and have it build a grace.ko
module. Then, rejigger the Kconfig options so that both nfsd and lockd
enable it automatically.
Signed-off-by: NJeff Layton <jlayton@primarydata.com>

We'd like to prevent local buffer overflows caused by malicious or
broken servers.  New xdr_stream style decoders can do that.

For efficiency, we also want to be able to pass xdr_streams from
call_encode() to all XDR encoding functions, rather than building
an xdr_stream in every XDR encoding function in the kernel.

Same idea as the NLM v3 XDR overhaul.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We'd like to prevent local buffer overflows caused by malicious or
broken servers.  New xdr_stream style decoders can do that.

For efficiency, we also eventually want to be able to pass xdr_streams
from call_encode() and call_decode() to all XDR encoding functions,
rather than building an xdr_stream in every XDR encoding and decoding
function in the kernel.

To do all of this, rewrite the XDR encoding and decoding functions in
fs/lockd/xdr.c to use xdr_streams.  This makes them more or less
incompatible with server-side XDR helper functions, so break them out
into a separate source file.

Static helper functions are left without the "inline" directive.  This
allows the compiler to choose automatically how to optimize these for
size or speed.

SHARE-related functionality doesn't seem to be used, as those
functions are hiding behind a #define that isn't set anywhere that I
can find.  And, they've been in there forever (at least as far back as
the kernel's git history goes), yet remain unused.  Let's take the
opportunity to bin them.  It should be easy enough for someone to
introduce proper XDR functions if at some point SHARE-related NLM
functionality is desired.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Rewrite grace period code to unify management of grace period across
lockd and nfsd.  The current code has lockd and nfsd cooperate to
compute a grace period which is satisfactory to them both, and then
individually enforce it.  This creates a slight race condition, since
the enforcement is not coordinated.  It's also more complicated than
necessary.

Here instead we have lockd and nfsd each inform common code when they
enter the grace period, and when they're ready to leave the grace
period, and allow normal locking only after both of them are ready to
leave.

We also expect the locks_start_grace()/locks_end_grace() interface here
to be simpler to build on for future cluster/high-availability work,
which may require (for example) putting individual filesystems into
grace, or enforcing grace periods across multiple cluster nodes.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!