pg_start_backup throws warning:could not read symbolic link

[rajv]

While executing pg_start_backup function in postgres 9.6 DB I am getting below warning

select pg_start_backup(to_char(now(), 'yyyy-mm-dd hh24:mi:ss'));

WARNING:  could not read symbolic link "pg_tblspc/oth_data_tbs": Invalid argument
WARNING:  could not read symbolic link "pg_tblspc/str_index": Invalid argument
WARNING:  could not read symbolic link "pg_tblspc/tbs_temp_default": Invalid argument
WARNING:  could not read symbolic link "pg_tblspc/oth_indx_tbs": Invalid argument
WARNING:  could not read symbolic link "pg_tblspc/str_data_ids": Invalid argument
WARNING:  could not read symbolic link "pg_tblspc/tbs_default": Invalid argument
 pg_start_backup
-----------------
 5/E0000028
(1 row)

[Banfa]

A quick Google suggests your data directory is corrupt and that you should rebuild your database cleanly; full answer here