rbd: add rbd_obj_watch_request_helper() helper

In the past, rbd_dev_header_watch_sync() used to handle both watch and
unwatch requests and was entangled and leaky.  Commit b30a01f2a307
("rbd: fix osd_request memory leak in __rbd_dev_header_watch_sync()")
split it into two separate functions.  This commit cleanly abstracts
the common bits, relying on the fixed rbd_obj_request_wait().

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

1 files changed, 53 insertions, 0 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 20147aec86f3..02cf7aba7679 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2971,6 +2971,59 @@ static void rbd_watch_cb(u64 ver, u64 notify_id, u8 opcode, void *data)
 }
 
 /*
+ * Send a (un)watch request and wait for the ack.  Return a request
+ * with a ref held on success or error.
+ */
+static struct rbd_obj_request *rbd_obj_watch_request_helper(
+                                                struct rbd_device *rbd_dev,
+                                                bool watch)
+{
+        struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
+        struct rbd_obj_request *obj_request;
+        int ret;
+
+        obj_request = rbd_obj_request_create(rbd_dev->header_name, 0, 0,
+                                             OBJ_REQUEST_NODATA);
+        if (!obj_request)
+                return ERR_PTR(-ENOMEM);
+
+        obj_request->osd_req = rbd_osd_req_create(rbd_dev, true, 1,
+                                                  obj_request);
+        if (!obj_request->osd_req) {
+                ret = -ENOMEM;
+                goto out;
+        }
+
+        osd_req_op_watch_init(obj_request->osd_req, 0, CEPH_OSD_OP_WATCH,
+                              rbd_dev->watch_event->cookie, 0, watch);
+        rbd_osd_req_format_write(obj_request);
+
+        if (watch)
+                ceph_osdc_set_request_linger(osdc, obj_request->osd_req);
+
+        ret = rbd_obj_request_submit(osdc, obj_request);
+        if (ret)
+                goto out;
+
+        ret = rbd_obj_request_wait(obj_request);
+        if (ret)
+                goto out;
+
+        ret = obj_request->result;
+        if (ret) {
+                if (watch)
+                        rbd_obj_request_end(obj_request);
+                goto out;
+        }
+
+        return obj_request;
+
+out:
+        rbd_obj_request_put(obj_request);
+        return ERR_PTR(ret);
+}
+
+/*
  * Initiate a watch request, synchronously.
  */
 static int rbd_dev_header_watch_sync(struct rbd_device *rbd_dev)