On 2012-06-11, Dimitrios Moustos <dot...@dotbit.ro> wrote: > Hello, > I have not found any information in the man page or otherwise that conflicts > with the bellow, it just does not seem like the following should be possible: > > # grep home /etc/fstab > 424dc014a22db950.f /home ffs ro,nodev,nosuid,noatime > # mount|grep home > /dev/sd0f on /home type ffs (local, noatime, nodev, nosuid, read-only) > # mount -uwo async /home > # mount|grep home > /dev/sd0f on /home type ffs (asynchronous, local, noatime, nodev, nosuid) > # mount -uro sync /home > # mount|grep /home > /dev/sd0f on /home type ffs (asynchronous, local, noatime, nodev, nosuid, > read-only, synchronous) > > > I am however not familiar with the intricacies of filesystems, which probably > makes me wrong. > At least posting this will make my curiosity go away. > >
async/noasync and sync/nosync are different things. >From GNATS PR kernel/6452: >Audit-Trail: State-Changed-From-To: open->closed State-Changed-By: thib State-Changed-When: Mon Apr 18 12:35:11 MDT 2011 State-Changed-Why: The async and sync mount options are not mutually exclusive. By default, metadata is written out synchronously while data is written out either synchronously or delayed. The async options allows metadata to be written out asynchronously, as well as data. The sync options forces all data io to be written out synchronously, but has no effect on metadata. So, what you end up with if you filesystem is mounted with both options set, is that metadata will be written out async, but data sync. Granted, this isn't very clear (even the kernel side is a bit murky), but this isn't a bug either.
