drbd: allow parallel promote/demote actions
We plan to use genl_family->parallel_ops = true in the future,
but need to review all possible interactions first.
For now, only selectively drop genl_lock() in drbd_set_role(),
instead serializing on our own internal resource->conf_update mutex.
We now can be promoted/demoted on many resources in parallel,
which may significantly improve cluster failover times
when fencing is required.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 20a1772..fe6295c 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -579,6 +579,7 @@
struct list_head resources;
struct res_opts res_opts;
struct mutex conf_update; /* mutex for ready-copy-update of net_conf and disk_conf */
+ struct mutex adm_mutex; /* mutex to serialize administrative requests */
spinlock_t req_lock;
unsigned susp:1; /* IO suspended by user */