Since we enabled auto-tuning for sunrpc TCP connections we do not
guarantee that there is enough write-space on each connection to
queue a reply.

If memory pressure causes the window to shrink too small, the request
throttling in sunrpc/svc will not accept any requests so no more requests
will be handled.  Even when pressure decreases the window will not
grow again until data is sent on the connection.
This means we get a deadlock:  no requests will be handled until there
is more space, and no space will be allocated until a request is
handled.

This can be simulated by modifying svc_tcp_has_wspace to inflate the
number of byte required and removing the 'svc_sock_setbufsize' calls
in svc_setup_socket.

I found that multiplying by 16 was enough to make the requirement
exceed the default allocation.  With this modification in place:
   mount -o vers=3,proto=tcp 127.0.0.1:/home /mnt
would block and eventually time out because the nfs server could not
accept any requests.

This patch relaxes the request throttling to always allow at least one
request through per connection.  It does this by checking both
  sk_stream_min_wspace() and xprt->xpt_reserved
are zero.
The first is zero when the TCP transmit queue is empty.
The second is zero when there are no RPC requests being processed.
When both of these are zero the socket is idle and so one more
request can safely be allowed through.

Applying this patch allows the above mount command to succeed cleanly.
Tracing shows that the allocated write buffer space quickly grows and
after a few requests are handled, the extra tests are no longer needed
to permit further requests to be processed.

The main purpose of request throttling is to handle the case when one
client is slow at collecting replies and the send queue gets full of
replies that the client hasn't acknowledged (at the TCP level) yet.
As we only change behaviour when the send queue is empty this main
purpose is still preserved.
Reported-by: NBen Myers <bpm@sgi.com>
Signed-off-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Though clients we care about mostly don't do this, it is possible for
rpc requests to be sent in multiple fragments.  Here we have a sanity
check to ensure that the final received rpc isn't too small--except that
the number we're actually checking is the length of just the final
fragment, not of the whole rpc.  So a perfectly legal rpc that's
unluckily fragmented could cause the server to close the connection
here.

Cc: stable@vger.kernel.org
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

If we detect that an rpc is too short, we abort and close the
connection.  Except, there's a bug here: we're leaving sk_datalen
nonzero without leaving any pages in the sk_pages array.  The most
likely result of the inconsistency is a subsequent crash in
svc_tcp_clear_pages.

Also demote the BUG_ON in svc_tcp_clear_pages to a WARN.

Cc: stable@kernel.org
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The datagram_*_ctl functions in net/ipv6/datagram.c are IPv6-specific.  Since
datagram_send_ctl is publicly exported it should be appropriately named to
reflect the fact that it's for IPv6 only.
Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It may be a matter of personal taste, but I find this makes the code
clearer.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Over TCP, RPC's are preceded by a single 4-byte field telling you how
long the rpc is (in bytes).  The spec also allows you to send an RPC in
multiple such records (the high bit of the length field is used to tell
you whether this is the final record).

We've survived for years without supporting this because in practice the
clients we care about don't use it.  But the userland rpc libraries do,
and every now and then an experimental client will run into this.  (Most
recently I noticed it while trying to write a pynfs check.)  And we're
really on the wrong side of the spec here--let's fix this.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Keep a separate field, sk_datalen, that tracks only the data contained
in a fragment, not including the fragment header.

For now, this is always just max(0, sk_tcplen - 4), but after we allow
multiple fragments sk_datalen will accumulate the total rpc data size
while sk_tcplen only tracks progress receiving the current fragment.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The full reclen doesn't include the fragment header, but sk_tcplen does.
Fix this to make it an apples-to-apples comparison.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Soon we want to support multiple fragments, in which case it may be
legal for a single fragment to be smaller than 8 bytes, so we'll want to
delay this check till we've reached the last fragment.

Also fix an outdated comment.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Byte-swapping in place is always a little dubious.

Let's instead define this field to always be big-endian, and do the
swapping on demand where we need it.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Replace multiple BUG_ON() calls with WARN_ON_ONCE() and early return when
sanity checking socket ownership (lock). The bind call will fail if the
socket was unsuccessfully reclassified.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

You can use nfsd/portlist to give nfsd additional sockets to listen on.
In theory you can also remove listening sockets this way.  But nobody's
ever done that as far as I can tell.

Also this was partially broken in 2.6.25, by
a217813f "knfsd: Support adding
transports by writing portlist file".

(Note that we decide whether to take the "delfd" case by checking for a
digit--but what's actually expected in that case is something made by
svc_one_sock_name(), which won't begin with a digit.)

So, let's just rip out this stuff.
Acked-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The only errors returned from xpo_recvfrom have been -EAGAIN and
-EAFNOSUPPORT.  The latter was removed by a previous patch.  That leaves
only -EAGAIN, which is treated just like 0 by the caller (svc_recv).

So, just ditch -EAGAIN and return 0 instead.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

None of the callers should see an unsupported address family (only one
of them even bothers to check for that case), so just check for the
buggy case in svc_addr_len and don't bother elsewhere.
Acked-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Order the code in a more boring way.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

There's some duplicate code here.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Mainly, use the kernel standard

	err = -ERROR;
	if (something_bad)
		goto out;
	normal case;

rather than

	if (something_bad)
		err = -ERROR
	else {
		normal case;
	}
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Use the kernel-standard ptr-or-error return convention instead of
passing a pointer to the error.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Examination of svc_tcp_clear_pages shows that it assumes sk_tcplen is
consistent with sk_pages[] (in particular, sk_pages[n] can't be NULL if
sk_tcplen would lead us to expect n pages of data).

svc_tcp_restore_pages zeroes out sk_pages[] while leaving sk_tcplen.
This is OK, since both functions are serialized by XPT_BUSY.  However,
that means the inconsistency must be repaired before dropping XPT_BUSY.

Therefore we should be ensuring that svc_tcp_save_pages repairs the
problem before exiting svc_tcp_recv_record on error.

Symptoms were a BUG() in svc_tcp_clear_pages.

Cc: stable@vger.kernel.org
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

dropwatch wrongly diagnose all received UDP packets as drops.

This patch removes trace_kfree_skb() done in skb_free_datagram_locked().

Locations calling skb_free_datagram_locked() should do it on their own.

As a result, drops are accounted on the right function.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Standardize the net core ratelimited logging functions.

Coalesce formats, align arguments.
Change a printk then vprintk sequence to use printf extension %pV.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Name them in a "backward compatible" manner, i.e. reuse or not
are still 1 and 0 respectively. The reuse value of 2 means that
the socket with it will forcibly reuse everyone else's port.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sunrpc/svcsock.c:412:22: warning: incorrect type in assignment
(different address spaces)
 - svc_partial_recvfrom now takes a struct kvec, so the variable
   save_iovbase needs to be an ordinary (void *)

Make a bunch of variables in net/sunrpc/xprtsock.c static

Fix a couple of "warning: symbol 'foo' was not declared. Should it be
static?" reports.

Fix a couple of conflicting function declarations.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This is a cleanup patch.
Service temporary sockets can be TCP or RDMA only. But XPT_CHNGBUF service
socket flag is checked only for UDP sockets on receive.
Thus (if I don't miss something non-obvious) this bit raising for temporary
sockets can be removed.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Fixes this build error when CONFIG_NET_NS is not set:

net/sunrpc/svcsock.c: In function 'svc_setup_socket':
net/sunrpc/svcsock.c:1412:40: error: 'struct sock_common' has no member named 'skc_net'
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Lockd and NFSd services will handle requests from and to many network
nsamespaces. And thus have to be registered and unregistered per network
namespace.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch makes svc_xprt inherit network namespace link from its socket.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

C assignment can handle struct in6_addr copying.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With calls to modular infrastructure, these files really
needs the full module.h header.  Call it out so some of the
cleanups of implicit and unrequired includes elsewhere can be
cleaned up.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

For IPv6 local address, lockd can not callback to client for
missing scope id when binding address at inet6_bind:

 324       if (addr_type & IPV6_ADDR_LINKLOCAL) {
 325               if (addr_len >= sizeof(struct sockaddr_in6) &&
 326                   addr->sin6_scope_id) {
 327                       /* Override any existing binding, if another one
 328                        * is supplied by user.
 329                        */
 330                       sk->sk_bound_dev_if = addr->sin6_scope_id;
 331               }
 332
 333               /* Binding to link-local address requires an interface */
 334               if (!sk->sk_bound_dev_if) {
 335                       err = -EINVAL;
 336                       goto out_unlock;
 337               }

Replacing svc_addr_u by sockaddr_storage, let rqstp->rq_daddr contains more info
besides address.
Reviewed-by: NJeff Layton <jlayton@redhat.com>
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NMi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Include the private header sunrpc.h to pickup the declaration of the
function svc_send_common to quiet the following sparse noise:

warning: symbol 'svc_send_common' was not declared. Should it be static?
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Change explicit references to CONFIG_NFS_V4_1 to implicit ones
Get rid of the unnecessary defines in backchannel_rqst.c and
bc_svc.c: the Makefile takes care of those dependency.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently when there's some failure to receive a callback (because we
couldn't find a matching xid, for example), we exit svc_recv with
sk_tcplen still set but without any pages saved with the socket.  This
will cause a crash later in svc_tcp_restore_pages.

Instead, make sure we reset that tcp information whether the callback
received failed or succeeded.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Allow the NFSv4 server to make use of TCP autotuning behaviour, which
was previously disabled by setting the sk_userlocks variable.

Set the receive buffers to be big enough to receive the whole RPC
request, and set this for the listening socket, not the accept socket.

Remove the code that readjusts the receive/send buffer sizes for the
accepted socket. Previously this code was used to influence the TCP
window management behaviour, which is no longer needed when autotuning
is enabled.

This can improve IO bandwidth on networks with high bandwidth-delay
products, where a large tcp window is required.  It also simplifies
performance tuning, since getting adequate tcp buffers previously
required increasing the number of nfsd threads.
Signed-off-by: NOlga Kornievskaia <aglo@citi.umich.edu>
Cc: Jim Rees <rees@umich.edu>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Ensure that we immediately read and buffer data from the incoming TCP
stream so that we grow the receive window quickly, and don't deadlock on
large READ or WRITE requests.

Also do some minor exit cleanup.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

It's much simpler just to copy the cb reply data than to play tricks
with pages.  Callback replies will typically be very small (at least
until we implement cb_getattr, in which case files with very long ACLs
could pose a problem), so there's no loss in efficiency.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

If the client sents a record too short to contain even the beginning of
the rpc header, then just close the connection.

The current code drops the record data and continues.  I don't see the
point.  It's a hopeless situation and simpler just to cut off the
connection completely.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Minor cleanup in preparation for later patches.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>