SUNRPC: Remove extra xprt_put()

While testing error cases where rpc_new_client() fails, I saw
some oopses.

If rpc_new_client() fails, it already invokes xprt_put().  Thus
__rpc_clone_client() does not need to invoke it again.

Introduced by commit 1b63a751 "SUNRPC: Refactor rpc_clone_client()"
Fri Sep 14, 2012.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org [>=3.7]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFSv4: Fix a memory leak in nfs4_discover_server_trunking

When we assign a new rpc_client to clp->cl_rpcclient, we need to destroy
the old one.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org [>=3.7]
NFSv4/4.1: Fix bugs in nfs4[01]_walk_client_list

It is unsafe to use list_for_each_entry_safe() here, because
when we drop the nn->nfs_client_lock, we pin the _current_ list
entry and ensure that it stays in the list, but we don't do the
same for the _next_ list entry. Use of list_for_each_entry() is
therefore the correct thing to do.

Also fix the refcounting in nfs41_walk_client_list().

Finally, ensure that the nfs_client has finished being initialised
and, in the case of NFSv4.1, that the session is set up.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Bryan Schumaker <bjschuma@netapp.com>
Cc: stable@vger.kernel.org [>= 3.7]
SUNRPC: Fix a potential memory leak in rpc_new_client

If the call to rpciod_up() fails, we currently leak a reference to the
struct rpc_xprt.
As part of the fix, we also remove the redundant check for xprt!=NULL.
This is already taken care of by the callers.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFSv4: Fix another potential state manager deadlock

Don't hold the NFSv4 sequence id while we check for open permission.
The call to ACCESS may block due to reboot recovery.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Merge tag 'nfs-for-3.9-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client bugfixes from Trond Myklebust:
 - fix for memory corruption issues in nfs4[01]_walk_client_list (stable)
 - fix for an Oopsable bug in rpc_clone_client (stable)
 - another state manager deadlock in the NFSv4 open code
 - memory leaks in nfs4_discover_server_trunking and rpc_new_client

* tag 'nfs-for-3.9-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFSv4: Fix another potential state manager deadlock
  SUNRPC: Fix a potential memory leak in rpc_new_client
  NFSv4/4.1: Fix bugs in nfs4[01]_walk_client_list
  NFSv4: Fix a memory leak in nfs4_discover_server_trunking
  SUNRPC: Remove extra xprt_put()