Merge tag 'nfs-for-3.9-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client bugfixes from Trond Myklebust:

 - Fix an Oops in the pNFS layoutget code

 - Fix a number of NFSv4 and v4.1 state recovery deadlocks and hangs due
   to the interaction of the session drain lock and state management
   locks.

 - Remove task->tk_xprt, which was hiding a lot of RCU dereferencing
   bugs

 - Fix a long standing NFSv3 posix lock recovery bug.

 - Revert commit 324d003b0cd8 ("NFS: add nfs_sb_deactive_async to avoid
   deadlock").  It turned out that the root cause of the deadlock was
   due to interactions with the workqueues that have now been resolved.

* tag 'nfs-for-3.9-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (22 commits)
  NLM: Ensure that we resend all pending blocking locks after a reclaim
  umount oops when remove blocklayoutdriver first
  sunrpc: silence build warning in gss_fill_context
  nfs: remove kfree() redundant null checks
  NFSv4.1: Don't decode skipped layoutgets
  NFSv4.1: Fix bulk recall and destroy of layouts
  NFSv4.1: Fix an ABBA locking issue with session and state serialisation
  NFSv4: Fix a reboot recovery race when opening a file
  NFSv4: Ensure delegation recall and byte range lock removal don't conflict
  NFSv4: Fix up the return values of nfs4_open_delegation_recall
  NFSv4.1: Don't lose locks when a server reboots during delegation return
  NFSv4.1: Prevent deadlocks between state recovery and file locking
  NFSv4: Allow the state manager to mark an open_owner as being recovered
  SUNRPC: Add missing static declaration to _gss_mech_get_by_name
  Revert "NFS: add nfs_sb_deactive_async to avoid deadlock"
  SUNRPC: Nuke the tk_xprt macro
  SUNRPC: Avoid RCU dereferences in the transport bind and connect code
  SUNRPC: Fix an RCU dereference in xprt_reserve
  SUNRPC: Pass pointers to struct rpc_xprt to the congestion window
  SUNRPC: Fix an RCU dereference in xs_local_rpcbind
  ...

1 files changed, 13 insertions, 8 deletions

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 33811db8788..846c34fdee9 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -430,21 +430,23 @@ __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
  */
 void xprt_release_rqst_cong(struct rpc_task *task)
 {
-	__xprt_put_cong(task->tk_xprt, task->tk_rqstp);
+	struct rpc_rqst *req = task->tk_rqstp;
+
+	__xprt_put_cong(req->rq_xprt, req);
 }
 EXPORT_SYMBOL_GPL(xprt_release_rqst_cong);
 
 /**
  * xprt_adjust_cwnd - adjust transport congestion window
+ * @xprt: pointer to xprt
  * @task: recently completed RPC request used to adjust window
  * @result: result code of completed RPC request
  *
  * We use a time-smoothed congestion estimator to avoid heavy oscillation.
  */
-void xprt_adjust_cwnd(struct rpc_task *task, int result)
+void xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result)
 {
 	struct rpc_rqst *req = task->tk_rqstp;
-	struct rpc_xprt *xprt = task->tk_xprt;
 	unsigned long cwnd = xprt->cwnd;
 
 	if (result >= 0 && cwnd <= xprt->cong) {
@@ -695,7 +697,7 @@ out_abort:
  */
 void xprt_connect(struct rpc_task *task)
 {
-	struct rpc_xprt	*xprt = task->tk_xprt;
+	struct rpc_xprt	*xprt = task->tk_rqstp->rq_xprt;
 
 	dprintk("RPC: %5u xprt_connect xprt %p %s connected\n", task->tk_pid,
 			xprt, (xprt_connected(xprt) ? "is" : "is not"));
@@ -722,13 +724,13 @@ void xprt_connect(struct rpc_task *task)
 		if (xprt_test_and_set_connecting(xprt))
 			return;
 		xprt->stat.connect_start = jiffies;
-		xprt->ops->connect(task);
+		xprt->ops->connect(xprt, task);
 	}
 }
 
 static void xprt_connect_status(struct rpc_task *task)
 {
-	struct rpc_xprt	*xprt = task->tk_xprt;
+	struct rpc_xprt	*xprt = task->tk_rqstp->rq_xprt;
 
 	if (task->tk_status == 0) {
 		xprt->stat.connect_count++;
@@ -832,7 +834,7 @@ static void xprt_timer(struct rpc_task *task)
 	spin_lock_bh(&xprt->transport_lock);
 	if (!req->rq_reply_bytes_recvd) {
 		if (xprt->ops->timer)
-			xprt->ops->timer(task);
+			xprt->ops->timer(xprt, task);
 	} else
 		task->tk_status = 0;
 	spin_unlock_bh(&xprt->transport_lock);
@@ -1091,7 +1093,7 @@ EXPORT_SYMBOL_GPL(xprt_free);
  */
 void xprt_reserve(struct rpc_task *task)
 {
-	struct rpc_xprt	*xprt = task->tk_xprt;
+	struct rpc_xprt	*xprt;
 
 	task->tk_status = 0;
 	if (task->tk_rqstp != NULL)
@@ -1099,7 +1101,10 @@ void xprt_reserve(struct rpc_task *task)
 
 	task->tk_timeout = 0;
 	task->tk_status = -EAGAIN;
+	rcu_read_lock();
+	xprt = rcu_dereference(task->tk_client->cl_xprt);
 	xprt->ops->alloc_slot(xprt, task);
+	rcu_read_unlock();
 }
 
 static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt)