linux-toradex.git/net/sunrpc/xprt.c, branch v4.3.1

SUNRPC: Lock the transport layer on shutdown

2015-09-19T20:37:43+00:00

Avoid all races with the connect/disconnect handlers by taking the
transport lock.

Reported-by:"Suzuki K. Poulose" 
Acked-by: Jeff Layton 
Signed-off-by: Trond Myklebust

SUNRPC: Ensure we release the TCP socket once it has been closed

2015-06-19T23:20:12+00:00

This fixes a regression introduced by commit caf4ccd4e88cf2 ("SUNRPC:
Make xs_tcp_close() do a socket shutdown rather than a sock_release").
Prior to that commit, the autoclose feature would ensure that an
idle connection would result in the socket being both disconnected and
released, whereas now only gets disconnected.

While the current behaviour is harmless, it does leave the port bound
until either RPC traffic resumes or the RPC client is shut down.

Reported-by: Steven Rostedt 
Signed-off-by: Trond Myklebust

SUNRPC: never enqueue a ->rq_cong request on ->sending

2015-06-16T15:13:21+00:00

If the sending queue has a task without ->rq_cong set at the front,
and then a number of tasks with ->rq_cong set such that they use
the entire congestion window, then the queue deadlocks.  The first
entry cannot be processed until later entries complete.

This scenario has been seen with a client using UDP to access a server,
and the network connection breaking for a period of time - it doesn't
recover.

It never really makes sense for an ->rq_cong request to be on the ->sending
queue, but it can happen when a request is being retried, and finds
the transport if locked (XPRT_LOCKED).  In this case we simple call
__xprt_put_cong() and the deadlock goes away.

Signed-off-by: NeilBrown 
Signed-off-by: Trond Myklebust

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

Merge branch 'bugfixes'

2015-04-23T19:16:27+00:00

* bugfixes:
  NFSv4: Return delegations synchronously in evict_inode
  SUNRPC: Fix a regression when reconnecting
  NFS: remount with security change should return EINVAL
  nfs: do not export discarded symbols
  NFSv4.1: don't export static symbol

sunrpc: make debugfs file creation failure non-fatal

2015-04-23T18:42:27+00:00

v2: gracefully handle the case where some dentry pointers end up NULL
    and be more dilligent about zeroing out dentry pointers

We currently have a problem that SELinux policy is being enforced when
creating debugfs files. If a debugfs file is created as a side effect of
doing some syscall, then that creation can fail if the SELinux policy
for that process prevents it.

This seems wrong. We don't do that for files under /proc, for instance,
so Bruce has proposed a patch to fix that.

While discussing that patch however, Greg K.H. stated:

    "No kernel code should care / fail if a debugfs function fails, so
     please fix up the sunrpc code first."

This patch converts all of the sunrpc debugfs setup code to be void
return functins, and the callers to not look for errors from those
functions.

This should allow rpc_clnt and rpc_xprt creation to work, even if the
kernel fails to create debugfs files for some reason.

Cc: Greg Kroah-Hartman 
Acked-by: "J. Bruce Fields" 
Signed-off-by: Jeff Layton 
Signed-off-by: Trond Myklebust

SUNRPC: Fix a regression when reconnecting

2015-03-27T16:24:36+00:00

If the task needs to give up the socket lock in order to allow a
reconnect to occur, then it must also clear the 'rq_bytes_sent' field
so that when it retransmits, it knows to start from the beginning.

Fixes: 718ba5b87343 ("SUNRPC: Add helpers to prevent socket create from racing")
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: 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