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 (file)
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -579,6 +579,7 @@ struct drbd_resource {
        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 */

diff --cc drivers/block/drbd/drbd_main.c
Simple merge

diff --cc drivers/block/drbd/drbd_nl.c
Simple merge