On 06/25/2014 12:16 PM, Ilya Dryomov wrote:
> Switch rbd_dev_header_{un,}watch_sync() to use the new helper and fix
> rbd_dev_header_unwatch_sync() to destroy watch_request structures
> before queuing watch-remove message while at it. This mistake slipped
> into commit b30a01f2a307 ("rbd: fix osd_request memory leak in
> __rbd_dev_header_watch_sync()") and could lead to "image still in use"
> errors on image removal.
You can see why--even if they were entangled--both setting up
and taking down the watch request were done in the same function.
So much of what they do is common, just slightly different.
Reviewed-by: Alex Elder <elder@xxxxxxxxxx>
> Signed-off-by: Ilya Dryomov <ilya.dryomov@xxxxxxxxxxx>
> ---
> drivers/block/rbd.c | 115 ++++++++-------------------------------------------
> 1 file changed, 17 insertions(+), 98 deletions(-)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 02cf7aba7679..d99aa81774f8 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -3040,130 +3040,49 @@ static int rbd_dev_header_watch_sync(struct rbd_device *rbd_dev)
> if (ret < 0)
> return ret;
>
> - rbd_assert(rbd_dev->watch_event);
> -
> - obj_request = rbd_obj_request_create(rbd_dev->header_name, 0, 0,
> - OBJ_REQUEST_NODATA);
> - if (!obj_request) {
> - ret = -ENOMEM;
> - goto out_cancel;
> + obj_request = rbd_obj_watch_request_helper(rbd_dev, true);
> + if (IS_ERR(obj_request)) {
> + ceph_osdc_cancel_event(rbd_dev->watch_event);
> + rbd_dev->watch_event = NULL;
> + return PTR_ERR(obj_request);
> }
>
> - obj_request->osd_req = rbd_osd_req_create(rbd_dev, true, 1,
> - obj_request);
> - if (!obj_request->osd_req) {
> - ret = -ENOMEM;
> - goto out_put;
> - }
> -
> - ceph_osdc_set_request_linger(osdc, obj_request->osd_req);
> -
> - osd_req_op_watch_init(obj_request->osd_req, 0, CEPH_OSD_OP_WATCH,
> - rbd_dev->watch_event->cookie, 0, 1);
> - rbd_osd_req_format_write(obj_request);
> -
> - ret = rbd_obj_request_submit(osdc, obj_request);
> - if (ret)
> - goto out_linger;
> -
> - ret = rbd_obj_request_wait(obj_request);
> - if (ret)
> - goto out_linger;
> -
> - ret = obj_request->result;
> - if (ret)
> - goto out_linger;
> -
> /*
> * A watch request is set to linger, so the underlying osd
> * request won't go away until we unregister it. We retain
> * a pointer to the object request during that time (in
> - * rbd_dev->watch_request), so we'll keep a reference to
> - * it. We'll drop that reference (below) after we've
> - * unregistered it.
> + * rbd_dev->watch_request), so we'll keep a reference to it.
> + * We'll drop that reference after we've unregistered it in
> + * rbd_dev_header_unwatch_sync().
> */
> rbd_dev->watch_request = obj_request;
>
> return 0;
> -
> -out_linger:
> - ceph_osdc_unregister_linger_request(osdc, obj_request->osd_req);
> -out_put:
> - rbd_obj_request_put(obj_request);
> -out_cancel:
> - ceph_osdc_cancel_event(rbd_dev->watch_event);
> - rbd_dev->watch_event = NULL;
> -
> - return ret;
> }
>
> /*
> * Tear down a watch request, synchronously.
> */
> -static int __rbd_dev_header_unwatch_sync(struct rbd_device *rbd_dev)
> +static void rbd_dev_header_unwatch_sync(struct rbd_device *rbd_dev)
> {
> - struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
> struct rbd_obj_request *obj_request;
> - int ret;
>
> rbd_assert(rbd_dev->watch_event);
> rbd_assert(rbd_dev->watch_request);
>
> - obj_request = rbd_obj_request_create(rbd_dev->header_name, 0, 0,
> - OBJ_REQUEST_NODATA);
> - if (!obj_request) {
> - ret = -ENOMEM;
> - goto out_cancel;
> - }
> -
> - obj_request->osd_req = rbd_osd_req_create(rbd_dev, true, 1,
> - obj_request);
> - if (!obj_request->osd_req) {
> - ret = -ENOMEM;
> - goto out_put;
> - }
> -
> - osd_req_op_watch_init(obj_request->osd_req, 0, CEPH_OSD_OP_WATCH,
> - rbd_dev->watch_event->cookie, 0, 0);
> - rbd_osd_req_format_write(obj_request);
> -
> - ret = rbd_obj_request_submit(osdc, obj_request);
> - if (ret)
> - goto out_put;
> -
> - ret = rbd_obj_request_wait(obj_request);
> - if (ret)
> - goto out_put;
> -
> - ret = obj_request->result;
> - if (ret)
> - goto out_put;
> -
> - /* We have successfully torn down the watch request */
> -
> - ceph_osdc_unregister_linger_request(osdc,
> - rbd_dev->watch_request->osd_req);
> + rbd_obj_request_end(rbd_dev->watch_request);
> rbd_obj_request_put(rbd_dev->watch_request);
> rbd_dev->watch_request = NULL;
>
> -out_put:
> - rbd_obj_request_put(obj_request);
> -out_cancel:
> + obj_request = rbd_obj_watch_request_helper(rbd_dev, false);
> + if (!IS_ERR(obj_request))
> + rbd_obj_request_put(obj_request);
> + else
> + rbd_warn(rbd_dev, "unable to tear down watch request (%ld)",
> + PTR_ERR(obj_request));
> +
> ceph_osdc_cancel_event(rbd_dev->watch_event);
> rbd_dev->watch_event = NULL;
> -
> - return ret;
> -}
> -
> -static void rbd_dev_header_unwatch_sync(struct rbd_device *rbd_dev)
> -{
> - int ret;
> -
> - ret = __rbd_dev_header_unwatch_sync(rbd_dev);
> - if (ret) {
> - rbd_warn(rbd_dev, "unable to tear down watch request: %d\n",
> - ret);
> - }
> }
>
> /*
>
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