The directio flag causes all I/O to a regular file to be Direct I/O, even if the O_DIRECT flag isn't used on the open() command.
The immutable flag marks the file immutable. The behavior is similar to the immutable flag in the ext2/3 filesystems. All write access is denied. Same as chattr +i.
The appendonly flag causes all data to be written at the end of the file. Same as chattr +a.
The noatime flag disables updates to the file's access time. Same as chattr +A.
The sync flag causes data written to the file to be sync'ed to stable storage immediately. Same as chattr +S.
Note: Unlike the original gfs_tool, the journaled data (jdata) flag is set with chattr +j and reset with chattr -j. Likewise, the inherit_jdata flag is set on a directory with chattr +j.