[sheepdog] [PATCH v5 8/8] sheep: make gateway requests only retry when requested object is local

[Liu Yuan]

On 05/28/2012 11:43 AM, levin li wrote:

> From: levin li <xingke.lwp at taobao.com>
> 
> We should not make gateway retry in check_request when the
> requested object in recovery is not local, in the case of requesting a
> non-local object we should make it retry in io_op_done(), if the
> requesting object is local, then we should make the gateway request
> to retry.
> 
> Signed-off-by: levin li <xingke.lwp at taobao.com>
> ---
>  sheep/sdnet.c |   39 ++++++++++++++++++++++++++-------------
>  1 file changed, 26 insertions(+), 13 deletions(-)
> 
> diff --git a/sheep/sdnet.c b/sheep/sdnet.c
> index 7cbaff8..18a1ced 100644
> --- a/sheep/sdnet.c
> +++ b/sheep/sdnet.c
> @@ -215,22 +215,35 @@ static int check_request(struct request *req)
>  	   retrying mechanism. */
>  	if (is_recoverying_oid(req->local_oid) &&
>  	    !(req->rq.flags & SD_FLAG_CMD_RECOVERY)) {
> -		if (req->rq.flags & SD_FLAG_CMD_IO_LOCAL) {
> -			/* Sheep peer request */
> -			if (is_recovery_init()) {
> -				req->rp.result = SD_RES_OBJ_RECOVERING;
> -				list_add_tail(&req->request_list,
> -						&sys->wait_rw_queue);
> -			} else
> -				list_add_tail(&req->request_list,
> -						&sys->wait_obj_queue);
> -		} else {
> -			/* Gateway request */
> -			list_add_tail(&req->request_list, &sys->req_wait_for_obj_list);
> +		/* Only if the requested object stays in gateway, then
> +		   the gateway request should be retried. */
> +		if (!(req->rq.flags & SD_FLAG_CMD_IO_LOCAL)) {
> +			struct sd_vnode *vnodes[SD_MAX_COPIES];
> +			int i, nr_copies;
> +
> +			nr_copies = get_nr_copies(req->vnodes);
> +			oid_to_vnodes(req->vnodes, req->local_oid,
> +				      nr_copies, vnodes);
> +			for (i = 0; i < nr_copies; i++) {
> +				struct sd_vnode *vnode = vnodes[i];
> +				if (is_myself(vnode->addr, vnode->port))
> +					break;
> +			}
> +			if (i == nr_copies)
> +				goto out;
>  		}


This check seems useless, req->local_oid already means it will access
the local copy.

Thanks,
Yuan