Re: [PATCH 1/3] libceph: call r_unsafe_callback when unsafe reply is received

["Yan, Zheng" <zheng.z.yan@intel.com>]

ping

I think this patch should goes into 3.11 or fix the issue by other means


On 06/24/2013 02:41 PM, Yan, Zheng wrote:
> From: "Yan, Zheng" <zheng.z.yan@intel.com>
> 
> We can't use !req->r_sent to check if OSD request is sent for the
> first time, this is because __cancel_request() zeros req->r_sent
> when OSD map changes. Rather than adding a new variable to struct
> ceph_osd_request to indicate if it's sent for the first time, We
> can call the unsafe callback only when unsafe OSD reply is received.
> If OSD's first reply is safe, just skip calling the unsafe callback.
> 
> The purpose of unsafe callback is adding unsafe request to a list,
> so that fsync(2) can wait for the safe reply. fsync(2) doesn't need
> to wait for a write(2) that hasn't returned yet. So it's OK to add
> request to the unsafe list when the first OSD reply is received.
> (ceph_sync_write() returns after receiving the first OSD reply)
> 
> Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
> ---
>  net/ceph/osd_client.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
> index 540dd29..dd47889 100644
> --- a/net/ceph/osd_client.c
> +++ b/net/ceph/osd_client.c
> @@ -1337,10 +1337,6 @@ static void __send_request(struct ceph_osd_client *osdc,
>  
>  	ceph_msg_get(req->r_request); /* send consumes a ref */
>  
> -	/* Mark the request unsafe if this is the first timet's being sent. */
> -
> -	if (!req->r_sent && req->r_unsafe_callback)
> -		req->r_unsafe_callback(req, true);
>  	req->r_sent = req->r_osd->o_incarnation;
>  
>  	ceph_con_send(&req->r_osd->o_con, req->r_request);
> @@ -1431,8 +1427,6 @@ static void handle_osds_timeout(struct work_struct *work)
>  
>  static void complete_request(struct ceph_osd_request *req)
>  {
> -	if (req->r_unsafe_callback)
> -		req->r_unsafe_callback(req, false);
>  	complete_all(&req->r_safe_completion);  /* fsync waiter */
>  }
>  
> @@ -1559,14 +1553,20 @@ static void handle_reply(struct ceph_osd_client *osdc, struct ceph_msg *msg,
>  	mutex_unlock(&osdc->request_mutex);
>  
>  	if (!already_completed) {
> +		if (req->r_unsafe_callback &&
> +		    result >= 0 && !(flags & CEPH_OSD_FLAG_ONDISK))
> +			req->r_unsafe_callback(req, true);
>  		if (req->r_callback)
>  			req->r_callback(req, msg);
>  		else
>  			complete_all(&req->r_completion);
>  	}
>  
> -	if (flags & CEPH_OSD_FLAG_ONDISK)
> +	if (flags & CEPH_OSD_FLAG_ONDISK) {
> +		if (req->r_unsafe_callback && already_completed)
> +			req->r_unsafe_callback(req, false);
>  		complete_request(req);
> +	}
>  
>  done:
>  	dout("req=%p req->r_linger=%d\n", req, req->r_linger);
>