[Ocfs2-devel] [PATCH V2] ocfs2/dlm: clear migration_pending when migration target goes down

[Joseph Qi]

On 2015/12/24 15:20, xuejiufei wrote:
> We have found a BUG on res->migration_pending when migrating
> lock resources. The situation is as follows.
> 
> dlm_mark_lockres_migration
>   res->migration_pending = 1;
>   __dlm_lockres_reserve_ast
>   dlm_lockres_release_ast returns with res->migration_pending remains
>       because other threads reserve asts
>   wait dlm_migration_can_proceed returns 1
>   >>>>>>> o2hb found that target goes down and remove target
>           from domain_map
>   dlm_migration_can_proceed returns 1
>   dlm_mark_lockres_migrating returns -ESHOTDOWN with
>       res->migration_pending still remains.
> 
> When reentering dlm_mark_lockres_migrating(), it will trigger
> the BUG_ON with res->migration_pending. So clear migration_pending
> when target is down.
> 
> Signed-off-by: Jiufei Xue <xuejiufei at huawei.com>
Reviewed-by: Joseph Qi <joseph.qi at huawei.com>

> ---
>  fs/ocfs2/dlm/dlmmaster.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
> index c43da7f..936e11b 100644
> --- a/fs/ocfs2/dlm/dlmmaster.c
> +++ b/fs/ocfs2/dlm/dlmmaster.c
> @@ -2843,6 +2843,8 @@ again:
>  	res->state &= ~DLM_LOCK_RES_BLOCK_DIRTY;
>  	if (!ret)
>  		BUG_ON(!(res->state & DLM_LOCK_RES_MIGRATING));
> +	else
> +		res->migration_pending = 0;
>  	spin_unlock(&res->spinlock);
> 
>  	/*
>