[IanCal]

You can add locks to objects, which restricts who can delete them and how, but requires bucket wide settings.

[maest]

BTW, this is true, but that is not locking in the "sync locking" sense.

[IanCal]

It's not the intended purpose but they can be used like this. Lock files can be written, will fail if they already exist - that gets you a distributed equivalent to flock doesn't it?