rbd: make rbd_obj_notify_ack() synchronous

commit 20e0af67ce88c657d0601977b9941a2256afbdaa upstream.

The only user of rbd_obj_notify_ack() is rbd_watch_cb(). It used
asynchronously with no tracking of when the notify ack completes, so
it may still be in progress when the osd_client is shut down.  This
results in a BUG() since the osd client assumes no requests are in
flight when it stops. Since all notifies are flushed before the
osd_client is stopped, waiting for the notify ack to complete before
returning from the watch callback ensures there are no notify acks in
flight during shutdown.

Rename rbd_obj_notify_ack() to rbd_obj_notify_ack_sync() to reflect
its new synchronous nature.

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index d9c3326c571f1c86254bf4be3d915f7979209e22..a1dff1cf1bca3a4e1e35815f946358c57e7f0e68 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2819,7 +2819,7 @@ out_err:
        obj_request_done_set(obj_request);
 }
 
-static int rbd_obj_notify_ack(struct rbd_device *rbd_dev, u64 notify_id)
+static int rbd_obj_notify_ack_sync(struct rbd_device *rbd_dev, u64 notify_id)
 {
        struct rbd_obj_request *obj_request;
        struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
@@ -2834,16 +2834,17 @@ static int rbd_obj_notify_ack(struct rbd_device *rbd_dev, u64 notify_id)
        obj_request->osd_req = rbd_osd_req_create(rbd_dev, false, obj_request);
        if (!obj_request->osd_req)
                goto out;
-       obj_request->callback = rbd_obj_request_put;
 
        osd_req_op_watch_init(obj_request->osd_req, 0, CEPH_OSD_OP_NOTIFY_ACK,
                                        notify_id, 0, 0);
        rbd_osd_req_format_read(obj_request);
 
        ret = rbd_obj_request_submit(osdc, obj_request);
-out:
        if (ret)
-               rbd_obj_request_put(obj_request);
+               goto out;
+       ret = rbd_obj_request_wait(obj_request);
+out:
+       rbd_obj_request_put(obj_request);
 
        return ret;
 }
@@ -2863,7 +2864,7 @@ static void rbd_watch_cb(u64 ver, u64 notify_id, u8 opcode, void *data)
        if (ret)
                rbd_warn(rbd_dev, ": header refresh error (%d)\n", ret);
 
-       rbd_obj_notify_ack(rbd_dev, notify_id);
+       rbd_obj_notify_ack_sync(rbd_dev, notify_id);
 }
 
 /*