[Cluster-devel] Why does dlm_lock function fails when downconvert a dlm lock?

[David Teigland <teigland@redhat.com>]

On Mon, Aug 16, 2021 at 09:41:18AM -0500, David Teigland wrote:
> On Fri, Aug 13, 2021 at 02:49:04PM +0800, Gang He wrote:
> > Hi David,
> > 
> > On 2021/8/13 1:45, David Teigland wrote:
> > > On Thu, Aug 12, 2021 at 01:44:53PM +0800, Gang He wrote:
> > > > In fact, I can reproduce this problem stably.
> > > > I want to know if this error happen is by our expectation? since there is
> > > > not any extreme pressure test.
> > > > Second, how should we handle these error cases? call dlm_lock function
> > > > again? maybe the function will fails again, that will lead to kernel
> > > > soft-lockup after multiple re-tries.
> > > 
> > > What's probably happening is that ocfs2 calls dlm_unlock(CANCEL) to cancel
> > > an in-progress dlm_lock() request.  Before the cancel completes (or the
> > > original request completes), ocfs2 calls dlm_lock() again on the same
> > > resource.  This dlm_lock() returns -EBUSY because the previous request has
> > > not completed, either normally or by cancellation.  This is expected.
> > These dlm_lock and dlm_unlock are invoked in the same node, or the different
> > nodes?
> 
> different

Sorry, same node