This patch introduces support to setup the callback xprt on the client side.
It allocates/ destroys the preallocated memory structures used to process
backchannel requests.

At setup time, xprt_setup_backchannel() is invoked to allocate one or
more rpc_rqst structures and substructures.  This ensures that they
are available when an RPC callback arrives.  The rpc_rqst structures
are maintained in a linked list attached to the rpc_xprt structure.
We keep track of the number of allocations so that they can be correctly
removed when the channel is destroyed.

When an RPC callback arrives, xprt_alloc_bc_request() is invoked to
obtain a preallocated rpc_rqst structure.  An rpc_xprt structure is
returned, and its RPC_BC_PREALLOC_IN_USE bit is set in
rpc_xprt->bc_flags.  The structure is removed from the the list
since it is now in use, and it will be later added back when its
user is done with it.

After the RPC callback replies, the rpc_rqst structure is returned
by invoking xprt_free_bc_request().  This clears the
RPC_BC_PREALLOC_IN_USE bit and adds it back to the list, allowing it
to be reused by a subsequent RPC callback request.

To be consistent with the reception of RPC messages, the backchannel requests
should be placed into the 'struct rpc_rqst' rq_rcv_buf, which is then in turn
copied to the 'struct rpc_rqst' rq_private_buf.

[nfs41: Preallocate rpc_rqst receive buffer for handling callbacks]
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
[Update copyright notice and explain page allocation]
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>

Adds new list of rpc_xprt structures, and a readers/writers lock to
protect the list.  The list is used to preallocate resources for
the backchannel during backchannel requests.  Callbacks are not
expected to cause significant latency, so only one callback will
be allowed at this time.

It also adds a pointer to the NFS callback service so that
requests can be directed to it for processing.

New callback members added to svc_serv. The NFSv4.1 callback service will
sleep on the svc_serv->svc_cb_waitq until new callback requests arrive.
The request will be queued in svc_serv->svc_cb_list. This patch adds this
list, the sleep queue and spinlock to svc_serv.

[nfs41: NFSv4.1 callback support]
Signed-off-by: NRicardo Labiaga <ricardo.labiaga@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>

See http://bugzilla.kernel.org/show_bug.cgi?id=13034

If the port gets into a TIME_WAIT state, then we cannot reconnect without
binding to a new port.
Tested-by: NPetr Vandrovec <petr@vandrovec.name>
Tested-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This fixes a regression against FreeBSD servers as reported by Tomas
Kasparek. Apparently when using RPC over a TCP socket, the FreeBSD servers
don't ever react to the client closing the socket, and so commit
e06799f9 (SUNRPC: Use shutdown() instead of
close() when disconnecting a TCP socket) causes the setup to hang forever
whenever the client attempts to close and then reconnect.

We break the deadlock by adding a 'linger2' style timeout to the socket,
after which, the client will abort the connection using a TCP 'RST'.

The default timeout is set to 15 seconds. A subsequent patch will put it
under user control by means of a systctl.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Provide an api to attempt to load any necessary kernel RPC
client transport module automatically. By convention, the
desired module name is "xprt"+"transport name". For example,
when NFS mounting with "-o proto=rdma", attempt to load the
"xprtrdma" module.
Signed-off-by: NTom Talpey <tmtalpey@gmail.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

rq_bufsize is not used.
Signed-off-by: NMike Sager <Mike.Sager@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

NFSv4 requires us to ensure that we break the TCP connection before we're
allowed to retransmit a request. However in the case where we're
retransmitting several requests that have been sent on the same
connection, we need to ensure that we don't interfere with the attempt to
reconnect and/or break the connection again once it has been established.

We therefore introduce a 'connection' cookie that is bumped every time a
connection is broken. This allows requests to track if they need to force a
disconnection.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The rest of the networking layer uses SOCK_ASYNC_NOSPACE to signal whether
or not we have someone waiting for buffer memory. Convert the SUNRPC layer
to use the same idiom.
Remove the unlikely()s in xs_udp_write_space and xs_tcp_write_space. In
fact, the most common case will be that there is nobody waiting for buffer
space.

SOCK_NOSPACE is there to tell the TCP layer whether or not the cwnd was
limited by the application window. Ensure that we follow the same idiom as
the rest of the networking layer here too.

Finally, ensure that we clear SOCK_ASYNC_NOSPACE once we wake up, so that
write_space() doesn't keep waking things up on xprt->pending.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: have the set up routines explicitly pass the strings to be used
for the transport name and NETID.  This removes a number of conditionals
and dependencies on rpc_xprt.prot, which is overloaded.

Tighten up type checking on the address_strings array while we're at it.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

In order to be able to support setting the timeo and retrans parameters on
a per-mountpoint basis, we move the rpc_timeout structure into the
rpc_clnt.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

xprt_disconnect() should really only be called when the transport shutdown
is completed, and it is time to wake up any pending tasks. Rename it to
xprt_disconnect_done() in order to reflect the semantical change.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Add an xprt->state bit to enable the TCP ->state_change() method to signal
whether or not the TCP connection is in the process of closing down.
This will to be used by the reconnection logic in a separate patch.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

When scheduling the autoclose RPC call, we want to ensure that we don't
race against the test_bit() call in xprt_clear_locked().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

To prepare for including non-sockets-based RPC transports, select
RPC transports by an identifier (to be used in following patches).
Signed-off-by: NTom Talpey <tmt@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

To prepare for including non-sockets-based RPC transports, move the
sockets-dependent definitions into their own file.
Signed-off-by: NTom Talpey <tmt@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

To prepare for including non-sockets-based RPC transports, change the
overly suggestive name of the transport creation arguments struct.
Signed-off-by: NTom Talpey <tmt@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

To allow transport capabilities to be loaded dynamically, provide an API
for registering and unregistering the transports with the RPC client.
Eventually xprt_create_transport() will be changed to search the list of
registered transports when initializing a fresh transport.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTom Talpey <tmt@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The rpcbind (v3+) netid is provided by each RPC client transport. This fixes
an omission in IPv6 rpcbind client support, and enables future extension.
Signed-off-by: NTom Talpey <tmt@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

"Universal addresses" are a string representation of an IP address and
port.  They are described fully in RFC 3530, section 2.2.  Add support
for generating them in the RPC client's socket transport module.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>

Add support for the NFS client's need to export volume information
with IP addresses formatted in hex instead of decimal.

This isn't used yet, but subsequent patches (not in this series) will
change the NFS client to use this functionality.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

In addition to binding to a local privileged port the NFS client should
allow binding to a specific local address. This is used by the server
for callbacks. The patch adds the necessary interface.
Signed-off-by: NFrank van Maarseveen <frankvm@frankvm.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Cleanup argument passing to functions for creating an RPC transport.
Signed-off-by: NFrank van Maarseveen <frankvm@frankvm.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 - net/sunrpc/xprtsock.c:1635:5: warning: symbol 'init_socket_xprt' was not
   declared. Should it be static?
 - net/sunrpc/xprtsock.c:1649:6: warning: symbol 'cleanup_socket_xprt' was
   not declared. Should it be static?
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Introduce a replacement for the in-kernel portmapper client that supports
all 3 versions of the rpcbind protocol.  This code is not used yet.

Original code by Groupe Bull updated for the latest kernel, with multiple
bug fixes.

Note that rpcb_clnt.c does not yet support registering via versions 3 and
4 of the rpcbind protocol.  That is planned for a later patch.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently rpc_malloc sets req->rq_buffer internally.  Make this a more
generic interface:  return a pointer to the new buffer (or NULL) and
make the caller set req->rq_buffer and req->rq_bufsize.  This looks much
more like kmalloc and eliminates the side effects.

To fix a potential deadlock, this patch also replaces GFP_NOFS with
GFP_NOWAIT in rpc_malloc.  This prevents async RPCs from sleeping outside
the RPC's task scheduler while allocating their buffer.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The RPC buffer size estimation logic in net/sunrpc/clnt.c always
significantly overestimates the requirements for the buffer size.
A little instrumentation demonstrated that in fact rpc_malloc was never
allocating the buffer from the mempool, but almost always called kmalloc.

To compute the size of the RPC buffer more precisely, split p_bufsiz into
two fields; one for the argument size, and one for the result size.

Then, compute the sum of the exact call and reply header sizes, and split
the RPC buffer precisely between the two.  That should keep almost all RPC
buffers within the 2KiB buffer mempool limit.

And, we can finally be rid of RPC_SLACK_SPACE!
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

For now we will assume that all transports will use the address format
buffers in the rpc_xprt struct to store their addresses.  Change
rpc_peer2str() to be a generic routine to handle this, and get rid of the
print_address() op in the rpc_xprt_ops vector.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Move the three fields for saving socket callback functions out of the
rpc_xprt structure and into a private data structure maintained in
net/sunrpc/xprtsock.c.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Move the socket-specific buffer size parameters for UDP sockets to a
private data structure maintained in net/sunrpc/xprtsock.c.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Move the socket-specific connection management fields out of the generic
rpc_xprt structure into a private data structure maintained in
net/sunrpc/xprtsock.c.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Move "XPRT_LAST_FRAG" and friends from xprt.h into xprtsock.c, and rename
them to use the naming scheme in use in xprtsock.c.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Move the TCP receive state variables from the generic rpc_xprt structure to
a private structure maintained inside net/sunrpc/xprtsock.c.

Also rename a function/variable pair to refer to RPC fragment headers
instead of record markers, to be consistent with types defined in
sunrpc/*.h.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The "sock" and "inet" fields are socket-specific.  Move them to a private
data structure maintained entirely within net/sunrpc/xprtsock.c
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Change the location where the rpc_xprt structure is allocated so each
transport implementation can allocate a private area from the same
chunk of memory.

Note also that xprt->ops->destroy, rather than xprt_destroy, is now
responsible for freeing rpc_xprt when the transport is destroyed.

Test plan:
Connectathon.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Move the xid field in the rpc_xprt structure to be in the same cache line
as the reserve_lock, since these are used at the same time.

Test plan:
None.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Separate delayable work items from non-delayable work items be splitting them
into a separate structure (delayed_work), which incorporates a work_struct and
the timer_list removed from work_struct.

The work_struct struct is huge, and this limits it's usefulness.  On a 64-bit
architecture it's nearly 100 bytes in size.  This reduces that by half for the
non-delayable type of event.
Signed-Off-By: NDavid Howells <dhowells@redhat.com>

The limit over UDP remains at 32K.  Also, make some of the apparently
arbitrary sizing constants clearer.

The biggest change here involves replacing NFSSVC_MAXBLKSIZE by a function of
the rqstp.  This allows it to be different for different protocols (udp/tcp)
and also allows it to depend on the servers declared sv_bufsiz.

Note that we don't actually increase sv_bufsz for nfs yet.  That comes next.
Signed-off-by: NGreg Banks <gnb@melbourne.sgi.com>
Signed-off-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

pure s/u32/__be32/

[AV: large part based on Alexey's patches]
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In a subsequent patch, this will allow the portmapper to take a reference
to the rpc_xprt for which it is updating the port number, fixing an Oops.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>