I was wondering whether the
noatime mount option implied the
nodiratime option; turned out it’s true!
Though mount’s man page (section 8) does not mention anything on the subject:
noatime: Access timestamps are not updated when a file is read
nodiratime: Do not update directory inode access times on this filesystem
Mount’s man page (section 2) is clearer:
MS_NOATIME: Do not update access times for (all types of) files on this file system
MS_NODIRATIME: Do not update access times for directories on this file system
As a directory is a file, setting noatime implies nodiratime consequently.
noatime is a superset of nodiratime, btw