rbd: use rbd_obj_watch_request_helper() helper

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.

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>

1 files 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);
-        }
 }
 
 /*