The current lockd does not reject reclaims that arrive outside of the
grace period.

Accepting a reclaim means promising to the client that no conflicting
locks were granted since last it held the lock.  We can meet that
promise if we assume the only lockers are nfs clients, and that they are
sufficiently well-behaved to reclaim only locks that they held before,
and that only reclaim locks have been permitted so far.  Once we leave
the grace period (and start permitting non-reclaims), we can no longer
keep that promise.  So we must start rejecting reclaims at that point.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Do all the grace period checks in svclock.c.  This simplifies the code a
bit, and will ease some later changes.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

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: J. Bruce Fields <bfields@citi.umich.edu>

since commit ff7d9756
"nfsd: use static memory for callback program and stats"
do_probe_callback uses a static callback program
(NFS4_CALLBACK) rather than the one set in clp->cl_callback.cb_prog
as passed in by the client in setclientid (4.0)
or create_session (4.1).

This patches introduces rpc_create_args.prognumber that allows
overriding program->number when creating rpc_clnt.
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Now that cb_stats are static (since commit
ff7d9756)
there's no need to clear them.

Initially I thought it might make sense to do
that every callback probing but since the stats
are per-program and they are shared between possibly
several client callback instances, zeroing them out
seems like the wrong thing to do.

Note that that commit also introduced a bug
since stats.program is also being cleared in the process
and it is not restored after the memset as it used to be.
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

The RPCB XDR functions are used for multiple procedures.  For instance,
rpcb_encode_getaddr() is used for RPCB_GETADDR, RPCB_SET, and
RPCB_UNSET.  Make the XDR debug messages more generic so they are less
confusing.

And, unlike in other RPC consumers in the kernel, a single debug flag
enables all levels of debug messages in the RPC bind client, including
XDR debug messages.  Since the XDR decoders already report success or
failure in this case, remove redundant debug messages in the mid-level
rpcb_register_call() function.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

With the new rpcbind code, a PMAP_UNSET will not have any effect on
services registered via rpcbind v3 or v4.

Implement a version of svc_unregister() that uses an RPCB_UNSET with
an empty netid string to make sure we have cleared *all* entries for
a kernel RPC service when shutting down, or before starting a fresh
instance of the service.

Use the new version only when CONFIG_SUNRPC_REGISTER_V4 is enabled;
otherwise, the legacy PMAP version is used to ensure complete
backwards-compatibility with the Linux portmapper daemon.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Clean up: When doing an RPCB_SET, make the kernel's rpcb client use the
shorthand "::" for the universal form of the IPv6 ANY address.

Without this patch, rpcbind will advertise:

  0000:0000:0000:0000:0000:0000:0000:0000.x.y

This is cosmetic only.  It cleans up the display of information from
/sbin/rpcinfo.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

TI-RPC is a user-space library of RPC functions that replaces ONC RPC
and allows RPC to operate in the new world of IPv6.

TI-RPC combines the concept of a transport protocol (UDP and TCP)
and a protocol family (PF_INET and PF_INET6) into a single identifier
called a "netid."  For example, "udp" means UDP over IPv4, and "udp6"
means UDP over IPv6.

For rpcbind, then, the RPC service tuple that is registered and
advertised is:

  [RPC program, RPC version, service address and port, netid]

instead of

  [RPC program, RPC version, port, protocol]

Service address is typically ANYADDR, but can be a specific address
of one of the interfaces on a multi-homed host.  The third item in
the new tuple is expressed as a universal address.

The current Linux rpcbind implementation registers a netid for both
protocol families when RPCB_SET is done for just the PF_INET6 version
of the netid (ie udp6 or tcp6).  So registering "udp6" causes a
registration for "udp" to appear automatically as well.

We've recently determined that this is incorrect behavior.  In the
TI-RPC world, "udp6" is not meant to imply that the registered RPC
service handles requests from AF_INET as well, even if the listener
socket does address mapping.  "udp" and "udp6" are entirely separate
capabilities, and must be registered separately.

The Linux kernel, unlike TI-RPC, leverages address mapping to allow a
single listener socket to handle requests for both AF_INET and AF_INET6.
This is still OK, but the kernel currently assumes registering "udp6"
will cover "udp" as well.  It registers only "udp6" for it's AF_INET6
services, even though they handle both AF_INET and AF_INET6 on the same
port.

So svc_register() actually needs to register both "udp" and "udp6"
explicitly (and likewise for TCP).  Until rpcbind is fixed, the
kernel can ignore the return code for the second RPCB_SET call.

Please merge this with commit 15231312:

    SUNRPC: Support IPv6 when registering kernel RPC services
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: Olaf Kirch <okir@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Clean up: Having two separate functions doesn't add clarity, so
eliminate one of them.  Use contemporary kernel coding conventions
where appropriate.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Adopt an approach similar to the RPC server's auth cache (from Aurelien
Charbon and Brian Haley).

Note nlm_lookup_host()'s existing IP address hash function has the same
issue with correctness on little-endian systems as the original IPv4 auth
cache hash function, so I've also updated it with a hash function similar
to the new auth cache hash function.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Update the nlm_cmp_addr() helper to support AF_INET6 as well as AF_INET
addresses.  New version takes two "struct sockaddr *" arguments instead of
"struct sockaddr_in *" arguments.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

To store larger addresses in the nsm_handle structure, make sm_addr a
sockaddr_storage.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

To store larger addresses in the nlm_host structure, make h_saddr a
sockaddr_storage.  And let's call it something more self-explanatory:
"saddr" could easily be mistaken for "server address".
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

To store larger addresses in the nlm_host structure, make h_addr a
sockaddr_storage, and add an address length field.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Clean up: Add extra type safety and squelch a few compiler complaints
in upcoming patches.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Make sure an address family is specified for source addresses passed to
nlm_lookup_host().  nlm_lookup_host() will need this when it becomes
capable of dealing with AF_INET6 addresses.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Knowing which source address is used for communicating with remote NLM
services can be helpful for debugging configuration problems on hosts
with multiple addresses.

Keep the dprintk debugging here, but adapt it so it displays AF_INET6
addresses properly.  There are also a couple of dprintk clean-ups as
well.

At some point we will aggregate the helpers that display presentation
format addresses into a single set of shared helpers.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

We're about to introduce some extra debugging messages in nlm_lookup_host().
Bring the coding style up to date first so we can cleanly introduce the new
debugging messages.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

In order to advertise NFS-related services on IPv6 interfaces via
rpcbind, the kernel RPC server implementation must use
rpcb_v4_register() instead of rpcb_register().

A new kernel build option allows distributions to use the legacy
v2 call until they integrate an appropriate user-space rpcbind
daemon that can support IPv6 RPC services.

I tried adding some automatic logic to fall back if registering
with a v4 protocol request failed, but there are too many corner
cases.  So I just made it a compile-time switch that distributions
can throw when they've replaced portmapper with rpcbind.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Create a separate server-level interface for unregistering RPC services.

The mechanics of, and the API for, registering and unregistering RPC
services will diverge further as support for IPv6 is added.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Bruce suggested there's no need to expose the difference between an error
sending the PMAP_SET request and an error reply from the portmapper to
rpcb_register's callers.  The user space equivalent of rpcb_register() is
pmap_set(3), which returns a bool_t : either the PMAP set worked, or it
didn't.  Simple.

So let's remove the "*okay" argument from rpcb_register() and
rpcb_v4_register(), and simply return an error if any part of the call
didn't work.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

My plan is to use an AF_INET listener on systems that support only IPv4,
and an AF_INET6 listener on systems that can support IPv6. Incoming
IPv4 packets will be posted to an AF_INET6 listener with a mapped IPv4
address.

Max Matveev <makc@sgi.com> says:
  Creating a single listener can be dangerous - if net.ipv6.bindv6only
  is enabled then it's possible to create another listener in v4
  namespace on the same port and steal the traffic from the "unifed"
  listener. You need to disable V6ONLY explicitly via a sockopt to stop
  that.

Set appropriate socket option on RPC server listener sockets to prevent
this.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

End lockd's grace period using schedule_delayed_work() instead of a
check on every pass through the main loop.

After a later patch, we'll depend on lockd to end its grace period even
if it's not currently handling requests; so it shouldn't depend on being
woken up from the main loop to do so.

Also, Nakano Hiroaki (who independently produced a similar patch)
noticed that the current behavior is buggy in the face of jiffies
wraparound:

	"lockd uses time_before() to determine whether the grace period
	has expired. This would seem to be enough to avoid timer
	wrap-around issues, but, unfortunately, that is not the case.
	The time_* family of comparison functions can be safely used to
	compare jiffies relatively close in time, but they stop working
	after approximately LONG_MAX/2 ticks. nfsd can suffer this
	problem because the time_before() comparison in lockd() is not
	performed until the first request comes in, which means that if
	there is no lockd traffic for more than LONG_MAX/2 ticks we are
	screwed.

	"The implication of this is that once time_before() starts
	misbehaving any attempt from a NFS client to execute fcntl()
	will be received with a NLM_LCK_DENIED_GRACE_PERIOD message for
	25 days (assuming HZ=1000). In other words, the 50 seconds grace
	period could turn into a grace period of 50 days or more.

	"Note: This bug was analyzed independently by Oda-san
	<oda@valinux.co.jp> and myself."
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Cc: Nakano Hiroaki <nakano.hiroaki@oss.ntt.co.jp>
Cc: Itsuro Oda <oda@valinux.co.jp>

The check here is currently harmless but unnecessary, since, as the
comment notes, there aren't any blocked-lock callbacks to process
during the grace period anyway.

And eventually we want to allow multiple grace periods that come and go
for different filesystems over the course of the lifetime of lockd, at
which point this check is just going to get in the way.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

I had a report from someone building a large NFS server that they were
unable to start more than 585 nfsd threads. It was reported against an
older kernel using the slab allocator, and I tracked it down to the
large allocation in nfsd_racache_init failing.

It appears that the slub allocator handles large allocations better,
but large contiguous allocations can often be problematic. There
doesn't seem to be any reason that the racache has to be allocated as a
single large chunk. This patch breaks this up so that the racache is
built up from separate allocations.

(Thanks also to Takashi Iwai for a bugfix.)
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Cc: Takashi Iwai <tiwai@suse.de>

Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

After using the encode_stateid helper the "p" pointer declared
by ENCODE_SEQID_OP_HEAD is warned as unused.
In the single site where it is still needed it can be declared
separately using the ENCODE_HEAD macro.
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

nfsd4_encode_open first reservation is currently for 36 + sizeof(stateid_t)
while it writes after the stateid a cinfo (20 bytes) and 5 more 4-bytes
words, for a total of 40 + sizeof(stateid_t).
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

This patch adds the CONFIG_FILE_LOCKING option which allows to remove
support for advisory locks. With this patch enabled, the flock()
system call, the F_GETLK, F_SETLK and F_SETLKW operations of fcntl()
and NFS support are disabled. These features are not necessarly needed
on embedded systems. It allows to save ~11 Kb of kernel code and data:

   text          data     bss     dec     hex filename
1125436        118764  212992 1457192  163c28 vmlinux.old
1114299        118564  212992 1445855  160fdf vmlinux
 -11137    -200       0  -11337   -2C49 +/-

This patch has originally been written by Matt Mackall
<mpm@selenic.com>, and is part of the Linux Tiny project.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: matthew@wil.cx
Cc: linux-fsdevel@vger.kernel.org
Cc: mpm@selenic.com
Cc: akpm@linux-foundation.org
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

RFC 2623 section 2.3.2 permits the server to bypass gss authentication
checks for certain operations that a client may perform when mounting.
In the case of a client that doesn't have some form of credentials
available to it on boot, this allows it to perform the mount unattended.
(Presumably real file access won't be needed until a user with
credentials logs in.)

Being slightly more lenient allows lots of old clients to access
krb5-only exports, with the only loss being a small amount of
information leaked about the root directory of the export.

This affects only v2 and v3; v4 still requires authentication for all
access.

Thanks to Peter Staubach testing against a Solaris client, which
suggesting addition of v3 getattr, to the list, and to Trond for noting
that doing so exposes no additional information.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Cc: Peter Staubach <staubach@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>

Teach svc_create_xprt() to use the correct ANY address for AF_INET6 based
RPC services.

No caller uses AF_INET6 yet.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Introduce and initialize an address family field in the svc_serv structure.

This field will determine what family to use for the service's listener
sockets and what families are advertised via the local rpcbind daemon.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>