[Ocfs2-devel] [PATCH] ocfs2/dlm: don't handle migrate lockres if already in shutdown

[Changwei Ge]

Hi Jun,

On 2018/3/1 17:27, piaojun wrote:
> We should not handle migrate lockres if we are already in
> 'DLM_CTXT_IN_SHUTDOWN', as that will cause lockres remains after
> leaving dlm domain. At last other nodes will get stuck into infinite
> loop when requsting lock from us.
> 
>      N1                             N2 (owner)
>                                     touch file
> 
> access the file,
> and get pr lock
> 
> umount
> 

Before migrating all lock resources, N1 should have already sent 
DLM_BEGIN_EXIT_DOMAIN_MSG in dlm_begin_exit_domain().
N2 will set ->exit_domain_map later.
So N2 can't take N1 as migration target.

How can the scenario your changelog describing happen?
Or if miss something?

Thanks,
Changwei

> migrate all lockres
> 
>                                     umount and migrate lockres to N1
> 
> leave dlm domain, but
> the lockres left
> unexpectedly, because
> migrate task has passed
> 
> Signed-off-by: Jun Piao <piaojun at huawei.com>
> Reviewed-by: Yiwen Jiang <jiangyiwen at huawei.com>
> ---
>   fs/ocfs2/dlm/dlmdomain.c   | 14 ++++++++++++++
>   fs/ocfs2/dlm/dlmdomain.h   |  1 +
>   fs/ocfs2/dlm/dlmrecovery.c |  9 +++++++++
>   3 files changed, 24 insertions(+)
> 
> diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c
> index e1fea14..3b7ec51 100644
> --- a/fs/ocfs2/dlm/dlmdomain.c
> +++ b/fs/ocfs2/dlm/dlmdomain.c
> @@ -675,6 +675,20 @@ static void dlm_leave_domain(struct dlm_ctxt *dlm)
>   	spin_unlock(&dlm->spinlock);
>   }
> 
> +int dlm_joined(struct dlm_ctxt *dlm)
> +{
> +	int ret = 0;
> +
> +	spin_lock(&dlm_domain_lock);
> +
> +	if (dlm->dlm_state == DLM_CTXT_JOINED)
> +		ret = 1;
> +
> +	spin_unlock(&dlm_domain_lock);
> +
> +	return ret;
> +}
> +
>   int dlm_shutting_down(struct dlm_ctxt *dlm)
>   {
>   	int ret = 0;
> diff --git a/fs/ocfs2/dlm/dlmdomain.h b/fs/ocfs2/dlm/dlmdomain.h
> index fd6122a..2f7f60b 100644
> --- a/fs/ocfs2/dlm/dlmdomain.h
> +++ b/fs/ocfs2/dlm/dlmdomain.h
> @@ -28,6 +28,7 @@
>   extern spinlock_t dlm_domain_lock;
>   extern struct list_head dlm_domains;
> 
> +int dlm_joined(struct dlm_ctxt *dlm);
>   int dlm_shutting_down(struct dlm_ctxt *dlm);
>   void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
>   					int node_num);
> diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c
> index ec8f758..9b3bc66 100644
> --- a/fs/ocfs2/dlm/dlmrecovery.c
> +++ b/fs/ocfs2/dlm/dlmrecovery.c
> @@ -1378,6 +1378,15 @@ int dlm_mig_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
>   	if (!dlm_grab(dlm))
>   		return -EINVAL;
> 
> +	if (!dlm_joined(dlm)) {
> +		mlog(ML_ERROR, "Domain %s not joined! "
> +				"lockres %.*s, master %u\n",
> +				dlm->name, mres->lockname_len,
> +				mres->lockname, mres->master);
> +		dlm_put(dlm);
> +		return -EINVAL;
> +	}
> +
>   	BUG_ON(!(mres->flags & (DLM_MRES_RECOVERY|DLM_MRES_MIGRATION)));
> 
>   	real_master = mres->master;
>