DAOS-15276 object: log refine

Features: dfs dfuse datamover hdf5

Required-githooks: true

Signed-off-by: Xuezhao Liu <xuezhao.liu@intel.com>

src/object/cli_obj.c

@@ -2223,7 +2223,11 @@ obj_iod_sgl_valid(daos_obj_id_t oid, unsigned int nr, daos_iod_t *iods,
 			for (j = 0; j < sg->sg_nr; j++) {
 				iov = sg->sg_iovs + j;
 				if (iov == NULL || (iov->iov_buf_len > 0 && iov->iov_buf == NULL)) {
-					D_ERROR("Bad iov\n");
+					if (iov == NULL)
+						D_ERROR("Bad iov - j %d, NULL iov\n", j);
+					else
+						D_ERROR("Bad iov - j %d, NULL iov_buf, "
+							"bul_len %zu\n", j, iov->iov_buf_len);
 					return -DER_INVAL;
 				}
 			}