get filesystem details from V$datafile

select distinct file_name from (
select distinct substr(name,1,instr(name,'/',1,3)-1)
file_name from v$datafile
union all
select distinct substr(name,1,instr(name,'/',1,3)-1)
file_name from v$controlfile
union all
select distinct substr(member,1,instr(member,'/',1,3)-1)
file_name from v$logfile
union all
select distinct substr(name,1,instr(name,'/',1,3)-1)
file_name from v$tempfile
);