NFSv4.1 skip rpc_call_done only on disconnected DS slot_table_waitq tasks

We reset all I/O on a disconnected data server through the pgio layer indicated
by the NFS_IOHDR_REDO flag.

Differentiate between on-the-wire tasks returning with an error which must
call rpc_call_done and tasks woken from the data server slot_table_waitq
waiting for a session slot with a status of zero which call rpc_exit in
rpc_prepare and need to skip rpc_call_done.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4filelayout.c

@@ -302,7 +302,8 @@ static void filelayout_read_call_done(struct rpc_task *task, void *data)
 
 	dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
 
-	if (test_bit(NFS_IOHDR_REDO, &rdata->header->flags))
+	if (test_bit(NFS_IOHDR_REDO, &rdata->header->flags) &&
+	    task->tk_status == 0)
 		return;
 
 	/* Note this may cause RPC to be resent */
@@ -399,7 +400,8 @@ static void filelayout_write_call_done(struct rpc_task *task, void *data)
 {
 	struct nfs_write_data *wdata = data;
 
-	if (test_bit(NFS_IOHDR_REDO, &wdata->header->flags))
+	if (test_bit(NFS_IOHDR_REDO, &wdata->header->flags) &&
+	    task->tk_status == 0)
 		return;
 
 	/* Note this may cause RPC to be resent */