Ceph POSIX Access Control Lists

configname: CONFIG_CEPH_FS_POSIX_ACL

Linux Kernel Configuration
└─>File systems
└─>Network File Systems
└─>Ceph POSIX Access Control Lists
In linux kernel since version 3.14 (release Date: 2014-03-30)  
POSIX Access Control Lists (ACLs) support permissions for users and
groups beyond the owner/group/world scheme.

If you don't know what Access Control Lists are, say N