On Thu, Mar 31, 2005 at 01:50:36PM -0800, Mark Fasheh wrote: > Well it's actually quite clean in ocfs2_dlmfs, part of that is likely > related to some design calls we made early on to simplify our userspace > locking. We don't do ranges (anywhere really), and we consider all userspace > lock requests to be synchronous. This does however result in a userspace API > which is extremely lightweight and dirt simple to use. > > mkdir gives you a new domain, files created within that directory correspond > to lock resource with the same name. Open O_RDONLY gets you a PR mode lock, > open RDWR gives you an EX mode lock. You can do NOQUEUE (trylock) ops with > O_NONBLOCK. Reads and writes to the file return and set the LVB accordingly. > > One can literally, create a domain, create locks within it and ship data via > the LVB all from a bash shell on my cluster nodes. > > I was able to write a trivial library wrapper (for those who don't want to > use shell for controlling dlm functionality) in about 600 lines. > --Mark > That's interesting, thanks. As far as our DLM is concerned it's a very small subset of the full functionality (so it would never replace the existing device interface) but I can see it might be useful. -- patrick
