If an ACL has been set on any file on a given file system, that file system has the
ext_attrattribute. This attribute can be seen using the following command:
# tune2fs -l filesystem-device
A file system that has acquired the
ext_attrattribute can be mounted with older kernels, but those kernels do not enforce any ACLs which have been set.
Versions of the
e2fsckutility included in version 1.22 and higher of the
e2fsprogspackage (including the versions in Red Hat Enterprise Linux 2.1 and 4) can check a file system with the
ext_attrattribute. Older versions refuse to check it.