linux-stable.git/include/linux/sunrpc/xprt.h, branch v4.2.4

SUNRPC: Transport fault injection

2015-06-10T22:37:26+00:00

It has been exceptionally useful to exercise the logic that handles
local immediate errors and RDMA connection loss.  To enable
developers to test this regularly and repeatably, add logic to
simulate connection loss every so often.

Fault injection is disabled by default. It is enabled with

  $ sudo echo xxx > /sys/kernel/debug/sunrpc/inject_fault/disconnect

where "xxx" is a large positive number of transport method calls
before a disconnect. A value of several thousand is usually a good
number that allows reasonable forward progress while still causing a
lot of connection drops.

These hooks are disabled when SUNRPC_DEBUG is turned off.

Signed-off-by: Chuck Lever 
Signed-off-by: Trond Myklebust

sunrpc: turn swapper_enable/disable functions into rpc_xprt_ops

2015-06-10T22:26:26+00:00

RDMA xprts don't have a sock_xprt, but an rdma_xprt, so the
xs_swapper_enable/disable functions will likely oops when fed an RDMA
xprt. Turn these functions into rpc_xprt_ops so that that doesn't
occur. For now the RDMA versions are no-ops that just return -EINVAL
on an attempt to swapon.

Cc: Chuck Lever 
Signed-off-by: Jeff Layton 
Reviewed-by: Chuck Lever 
Signed-off-by: Trond Myklebust

sunrpc: make xprt->swapper an atomic_t

2015-06-10T22:26:18+00:00

Split xs_swapper into enable/disable functions and eliminate the
"enable" flag.

Currently, it's racy if you have multiple swapon/swapoff operations
running in parallel over the same xprt. Also fix it so that we only
set it to a memalloc socket on a 0->1 transition and only clear it
on a 1->0 transition.

Cc: Mel Gorman 
Signed-off-by: Jeff Layton 
Reviewed-by: Chuck Lever 
Signed-off-by: Trond Myklebust

SUNRPC: Fix a backchannel race

2015-06-05T15:15:43+00:00

We need to allow the server to send a new request immediately after we've
replied to the previous one. Right now, there is a window between the
send and the release of the old request in rpc_put_task(), where the
server could send us a new backchannel RPC call, and we have no
request to service it.

Signed-off-by: Trond Myklebust

SUNRPC: Remove the redundant XPRT_CONNECTION_CLOSE flag

2015-02-09T16:26:06+00:00

Signed-off-by: Trond Myklebust

SUNRPC: Cleanup to remove remaining uses of XPRT_CONNECTION_ABORT

2015-02-09T14:20:40+00:00

Signed-off-by: Trond Myklebust

SUNRPC: Remove TCP client connection reset hack

2015-02-09T02:47:30+00:00

Instead we rely on SO_REUSEPORT to provide the reconnection semantics
that we need for NFSv2/v3.

Signed-off-by: Trond Myklebust

SUNRPC: Add helpers to prevent socket create from racing

2015-02-09T02:47:29+00:00

The socket lock is currently held by the task that is requesting the
connection be established. While that is efficient in the case where
the connection happens quickly, it is racy in the case where it doesn't.
What we really want is for the connect helper to be able to block access
to the socket while it is being set up.

This patch does so by arranging to transfer the socket lock from the
task that is requesting the connect attempt, and then releasing that
lock once everything is done.
This scheme also gives us automatic protection against collisions with
the RPC close code, so we can kill the cancel_delayed_work_sync()
call in xs_close().

Signed-off-by: Trond Myklebust

sunrpc: add a debugfs rpc_xprt directory with an info file in it

2014-11-27T18:14:52+00:00

Add a new directory heirarchy under the debugfs sunrpc/ directory:

    sunrpc/
        rpc_xprt/
            /

Within that directory, we can put files that give info about the
xprts. We do have the (minor) problem that there is no succinct,
unique identifier for rpc_xprts. So we generate them synthetically
with a static atomic_t counter.

For now, this directory just holds an "info" file, but we may add
other files to it in the future.

Signed-off-by: Jeff Layton 
Signed-off-by: Trond Myklebust

SUNRPC: Don't wake tasks during connection abort

2014-09-25T03:06:56+00:00

When aborting a connection to preserve source ports, don't wake the task in
xs_error_report.  This allows tasks with RPC_TASK_SOFTCONN to succeed if the
connection needs to be re-established since it preserves the task's status
instead of setting it to the status of the aborting kernel_connect().

This may also avoid a potential conflict on the socket's lock.

Signed-off-by: Benjamin Coddington 
Cc: stable@vger.kernel.org # 3.14+
Signed-off-by: Trond Myklebust