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From: David Teigland <teigland@redhat.com>
To: cluster-devel.redhat.com
Subject: [Cluster-devel] Why does dlm_lock function fails when downconvert a dlm lock?
Date: Thu, 12 Aug 2021 12:45:23 -0500	[thread overview]
Message-ID: <20210812174523.GC1757@redhat.com> (raw)
In-Reply-To: <74009531-f6ef-4ef9-b969-353684006ddc@suse.com>

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.

A couple options to try: wait for the original request to complete
(normally or by cancellation) before calling dlm_lock() again, or retry
dlm_lock() on -EBUSY.

Dave



  reply	other threads:[~2021-08-12 17:45 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-11 10:38 [Cluster-devel] Why does dlm_lock function fails when downconvert a dlm lock? Gang He
2021-08-11 20:35 ` Alexander Aring
2021-08-12  5:44   ` Gang He
2021-08-12 17:45     ` David Teigland [this message]
2021-08-13  6:49       ` Gang He
2021-08-16 14:41         ` David Teigland
2021-08-16 14:50           ` David Teigland

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