glusterd: Start rebalance only where required

Gluster was starting rebalance processes on peers where it wasn't
required in two cases.
- For a normal rebalance command on a volume, rebalance processes were
  started on all peers instead of just the peers which contain bricks of
  the volume
- For rebalance process being restarted by a volume sync, caused by a
  new peer being probed or a peer restarting, rebalance processes were
  started on all peers, for both a normal rebalance and for remove-brick
  needing rebalance.

This patch adds a new check before starting rebalance process in the
above two cases.
- For rebalance process required by a rebalance command, each peer will
  check if it contains atleast one brick of the volume
- For rebalance process required by a remove-brick command, each peer
  will check if it contains atleast one of the bricks being removed

Change-Id: I512da16994f0d5482889c3a009c46dc20a8a15bb
BUG: 1031887
Signed-off-by: Kaushal M <kaushal@redhat.com>
Reviewed-on: http://review.gluster.org/6301
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Krutika Dhananjay <kdhananj@redhat.com>
Reviewed-by: Anand Avati <avati@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-utils.h b/xlators/mgmt/glusterd/src/glusterd-utils.h
index 57120fe3942..5b0cfca7b55 100644
--- a/xlators/mgmt/glusterd/src/glusterd-utils.h
+++ b/xlators/mgmt/glusterd/src/glusterd-utils.h
@@ -573,4 +573,7 @@ glusterd_check_gsync_running_local (char *master, char *slave,
 
 gf_boolean_t
 glusterd_is_status_tasks_op (glusterd_op_t op, dict_t *dict);
+
+gf_boolean_t
+gd_should_i_start_rebalance  (glusterd_volinfo_t *volinfo);
 #endif