On RedHat, CentOS, and probably other RPM-based distributions, the
/etc/filesystems file lists the filesystems that are known to the
system, i.e. those filesystems that can be mounted without specifying
the filesystem type. The contents of that file in a minimal CentOS
installation are:
[root@c6min ~]# cat /etc/filesystems
ext4
ext3
ext2
nodev proc
nodev devpts
iso9660
vfat
hfs
hfsplus