dlm: fix up memory allocation flags

Use ls_allocation for memory allocations, which a cluster fs sets to
GFP_NOFS.  Use GFP_NOFS for allocations when no lockspace struct is
available.  Taking dlm locks needs to avoid calling back into the
cluster fs because write-out can require taking dlm locks.

Cc: Christine Caulfield <ccaulfie@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

fs/dlm/lowcomms.c

@@ -295,6 +295,7 @@ static int add_sock(struct socket *sock, struct connection *con)
 	con->sock->sk->sk_write_space = lowcomms_write_space;
 	con->sock->sk->sk_state_change = lowcomms_state_change;
 	con->sock->sk->sk_user_data = con;
+	con->sock->sk->sk_allocation = GFP_NOFS;
 	return 0;
 }