[HARDY 1/2 ] SRU: Bug#253004 nfsd4: probe callback channel only once

[Manoj Iyer]

SRU JUSTIFICATION:

IMPACT: Oops in sunrpc:rpc_shutdown_client
Fix: likely related to: #212485 kernel bug rpc nfs client. Backported 
patch to Hardy.
TEST: Test kernel in http://people.ubuntu.com/~manjo/lp253004-hardy/ was 
tested by community and reported to work.


The following changes since commit 
7758896776e7991a8fe5dc62d83fae68648fdd7d:
   Brad Figg (1):
         UBUNTU: [Hardy SRU][SAUCE]Add information to recognize Toshiba 
Satellite Pro M10 Alps Touchpad

are available in the git repository at:

   git://kernel.ubuntu.com/manjo/ubuntu-hardy.git lp253004

J. Bruce Fields (2):
       nfsd: move callback rpc_client creation into separate thread
       nfsd4: probe callback channel only once

  fs/nfsd/nfs4callback.c |   80 
++++++++++++++++++++++++-----------------------
  fs/nfsd/nfs4state.c    |    3 +-
  2 files changed, 42 insertions(+), 41 deletions(-)

>From 3011a223e977fb48696d246c2933a1fc2827dbac Mon Sep 17 00:00:00 2001
From: J. Bruce Fields <bfields at citi.umich.edu>
Date: Thu, 22 Nov 2007 13:54:18 -0500
Subject: [PATCH] nfsd4: probe callback channel only once

Bug: 253004
BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/253004

Our callback code doesn't actually handle concurrent attempts to probe
the callback channel.  Some rethinking of the locking may be required.
However, we can also just move the callback probing to this case.  Since
this is the only time a client is "confirmed" (and since that can only
happen once in the lifetime of a client), this ensures we only probe
once.

Signed-off-by: J. Bruce Fields <bfields at citi.umich.edu>
---
  fs/nfsd/nfs4callback.c |    4 ++--
  fs/nfsd/nfs4state.c    |    3 +--
  2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 698376b..a292640 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -370,8 +370,6 @@ static int do_probe_callback(void *data)
  		.flags		= (RPC_CLNT_CREATE_NOPING),
  	};

-	if (atomic_read(&cb->cb_set))
-		return;
  	struct rpc_message msg = {
  		.rpc_proc       = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL],
  		.rpc_argp       = clp,
@@ -379,6 +377,8 @@ static int do_probe_callback(void *data)
  	struct rpc_clnt *client;
  	int status;

+	BUG_ON(atomic_read(&clp->cl_callback.cb_set));
+
  	/* Initialize address */
  	memset(&addr, 0, sizeof(addr));
  	addr.sin_family = AF_INET;
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 31673cd..9d81c71 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -948,6 +948,7 @@ nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
  			}
  			move_to_confirmed(unconf);
  			conf = unconf;
+			nfsd4_probe_callback(conf);
  			status = nfs_ok;
  		}
  	} else if ((!conf || (conf && !same_verf(&conf->cl_confirm, &confirm)))
@@ -965,8 +966,6 @@ nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
  		status = nfserr_clid_inuse;
  	}
  out:
-	if (!status)
-		nfsd4_probe_callback(conf);
  	nfs4_unlock_state();
  	return status;
  }
-- 
1.6.0.4

Cheers
--- manjo