[sheepdog] [PATCH] sheep: fix incorrect status transition during joining cluster

[Hitoshi Mitake]

At Sun,  9 Jun 2013 02:18:28 +0900,
Hitoshi Mitake wrote:
> 
> Current sheep set jm->cluster_status SD_STATUS_OK if
> 1. itself is a first node to join the cluster, and
> 2. a number of nodes of latest epoch is 1
> 
> This is an invalid behavior. For example, the behavior allows such a
> situation:
> 1. create a cluster with 2 nodes
> 2. format the cluster with --copies 2
> 3. kill single sheep
> 4. shutdown the cluster
> 5. launch single sheep
> 6. the status of the cluster is SD_STATUS_OK
> 
> This patch solves the problem. The second condition is now checked
> with have_enough_zones().
> 
> Signed-off-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>
> ---
>  sheep/group.c |   10 ++--------
>  1 files changed, 2 insertions(+), 8 deletions(-)
> 
> diff --git a/sheep/group.c b/sheep/group.c
> index f74ef10..48040bf 100644
> --- a/sheep/group.c
> +++ b/sheep/group.c
> @@ -994,12 +994,10 @@ enum cluster_join_result sd_check_join_cb(const struct sd_node *joining,
>  	}
>  
>  	if (node_is_local(joining)) {
> -		struct sd_node entries[SD_MAX_NODES];
> -		int nr_entries;
>  		uint32_t epoch;
>  
>  		/*
> -		 * If I'm the first sheep joins in corosync, I
> +		 * If I'm the first sheep joins the cluster, I
>  		 * becomes the master without sending JOIN.
>  		 */
>  
> @@ -1017,14 +1015,10 @@ enum cluster_join_result sd_check_join_cb(const struct sd_node *joining,
>  			return CJ_RES_FAIL;
>  		}
>  
> -		nr_entries = epoch_log_read(epoch, entries, sizeof(entries));
> -		if (nr_entries == -1)
> -			return CJ_RES_FAIL;
> -
>  		sys->epoch = epoch;
>  		jm->ctime = get_cluster_ctime();
>  
> -		if (nr_entries == 1)
> +		if (have_enough_zones())
>  			jm->cluster_status = SD_STATUS_OK;
>  		return CJ_RES_SUCCESS;
>  	}

Sorry, this have_enough_zones() is invalid because the sheep doesn't
have current_vnode_info at that point.

I'll fix the problem and send v2 later.

Thanks,
Hitoshi