NFS: Ensure that the asynchronous RPC calls complete on nfsiod.

We want to ensure that rpc_call_ops that involve mntput() are run on nfsiod
rather than on rpciod, so that they don't deadlock when the resulting
umount calls rpc_shutdown_client(). Hence we specify that read, write and
commit calls must complete on nfsiod.
Ditto for NFSv4 open, lock, locku and close asynchronous calls.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/direct.c

@@ -280,6 +280,7 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_direct_req *dreq,
 		.rpc_client = NFS_CLIENT(inode),
 		.rpc_message = &msg,
 		.callback_ops = &nfs_read_direct_ops,
+		.workqueue = nfsiod_workqueue,
 		.flags = RPC_TASK_ASYNC,
 	};
 	unsigned int pgbase;
@@ -446,6 +447,7 @@ static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq)
 	struct rpc_task_setup task_setup_data = {
 		.rpc_client = NFS_CLIENT(inode),
 		.callback_ops = &nfs_write_direct_ops,
+		.workqueue = nfsiod_workqueue,
 		.flags = RPC_TASK_ASYNC,
 	};
 
@@ -537,6 +539,7 @@ static void nfs_direct_commit_schedule(struct nfs_direct_req *dreq)
 		.rpc_message = &msg,
 		.callback_ops = &nfs_commit_direct_ops,
 		.callback_data = data,
+		.workqueue = nfsiod_workqueue,
 		.flags = RPC_TASK_ASYNC,
 	};
 
@@ -683,6 +686,7 @@ static ssize_t nfs_direct_write_schedule_segment(struct nfs_direct_req *dreq,
 		.rpc_client = NFS_CLIENT(inode),
 		.rpc_message = &msg,
 		.callback_ops = &nfs_write_direct_ops,
+		.workqueue = nfsiod_workqueue,
 		.flags = RPC_TASK_ASYNC,
 	};
 	size_t wsize = NFS_SERVER(inode)->wsize;