Re: [libvirt] [PATCH 2/8] Basic framework for lock manager plugins
On Wed, Nov 24, 2010 at 03:08:41PM -0500, David Teigland wrote:
LOCK_MODE_NONE - the lock manager is unused, and it's up to the
application to do its own locking or coordination when accessing the
resource, e.g. if there's a clustered db or fs on the device that does its
own coordination. You seem to be calling this SHARED, but there's
actually no lock or exclusion that a lock manager would implement for this
kind of usage.
I failed to mention that with a more elaborate set of lock modes like a
dlm uses, the CW "concurrent write" mode fits the use case of leaving the
coordination to the application. Simpler lock managers only support
Shared or Exclusive, of course, in which case "None" would apply.
Dave