nfs: Send atime and mtime as a 64bit value

RFC 3530 says that the seconds value of a nfstime4 structure is a 64bit
value, but we are instead sending a 32-bit 0 and then a 32bit conversion
of the 64bit Linux value.  This means that if we try to set atime to a
value before the epoch (touch -t 196001010101) the client will only send
part of the new value due to lost precision.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4xdr.c

@@ -1058,8 +1058,7 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap, const
 	if (iap->ia_valid & ATTR_ATIME_SET) {
 		bmval1 |= FATTR4_WORD1_TIME_ACCESS_SET;
 		*p++ = cpu_to_be32(NFS4_SET_TO_CLIENT_TIME);
-		*p++ = cpu_to_be32(0);
-		*p++ = cpu_to_be32(iap->ia_atime.tv_sec);
+		p = xdr_encode_hyper(p, (s64)iap->ia_atime.tv_sec);
 		*p++ = cpu_to_be32(iap->ia_atime.tv_nsec);
 	}
 	else if (iap->ia_valid & ATTR_ATIME) {
@@ -1069,8 +1068,7 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap, const
 	if (iap->ia_valid & ATTR_MTIME_SET) {
 		bmval1 |= FATTR4_WORD1_TIME_MODIFY_SET;
 		*p++ = cpu_to_be32(NFS4_SET_TO_CLIENT_TIME);
-		*p++ = cpu_to_be32(0);
-		*p++ = cpu_to_be32(iap->ia_mtime.tv_sec);
+		p = xdr_encode_hyper(p, (s64)iap->ia_mtime.tv_sec);
 		*p++ = cpu_to_be32(iap->ia_mtime.tv_nsec);
 	}
 	else if (iap->ia_valid & ATTR_MTIME) {