NFSv4: Handle NFS4ERR_DELAY and NFS4ERR_GRACE in nfs4_open_delegation_recall

A server shouldn't normally return NFS4ERR_GRACE if the client holds a
delegation, since no conflicting lock reclaims can be granted, however
the spec does not require the server to grant the open in this
instance

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

fs/nfs/nfs4proc.c

@@ -1432,6 +1432,12 @@ int nfs4_open_delegation_recall(struct nfs_open_context *ctx, struct nfs4_state
 			case -ENOMEM:
 				err = 0;
 				goto out;
+			case -NFS4ERR_DELAY:
+			case -NFS4ERR_GRACE:
+				set_bit(NFS_DELEGATED_STATE, &state->flags);
+				ssleep(1);
+				err = -EAGAIN;
+				goto out;
 		}
 		set_bit(NFS_DELEGATED_STATE, &state->flags);
 		err = nfs4_handle_exception(server, err, &exception);