glusterd: Volume locks and transaction specific opinfos

With this patch we are replacing the existing cluster-wide
lock taken on glusterds across the cluster, with volume locks
which are also taken on glusterds across the cluster, but are
volume specific. So with the volume locks we are able to perform
more than one gluster operation at the same time, as long as the
operations are being performed on different volumes.

We maintain a global list of volume-locks (using a dict for a list)
where the key is the volume name, and which saves the uuid of the
originator glusterd. These locks are held and released per volume
transaction.

In order to acheive multiple gluster operations occuring at the
same time, we also separate opinfos in the op-state-machine, as a
part of this patch. To do so, we generate a unique transaction-id
(uuid) per gluster transaction. An opinfo is then associated with
this transaction id, which is used throughout the transaction. We
maintain a run-time global list(using a dict) of transaction-ids,
and their respective opinfos to achieve this.

Upstream Feature Page: http://www.gluster.org/community/documentation/index.php/Features/glusterd-volume-locks

Change-Id: Iaad505a854bac8de8f83beec0357eb6cde3f7ea8
BUG: 1011470
Signed-off-by: Avra Sengupta <asengupt@redhat.com>
Reviewed-on: http://review.gluster.org/5994
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-locks.h b/xlators/mgmt/glusterd/src/glusterd-locks.h
new file mode 100644
index 00000000000..2a8cc20ed25
--- /dev/null
+++ b/xlators/mgmt/glusterd/src/glusterd-locks.h
@@ -0,0 +1,38 @@
+/*
+   Copyright (c) 2013-2014 Red Hat, Inc. <http://www.redhat.com>
+   This file is part of GlusterFS.
+
+   This file is licensed to you under your choice of the GNU Lesser
+   General Public License, version 3 or any later version (LGPLv3 or
+   later), or the GNU General Public License, version 2 (GPLv2), in all
+   cases as published by the Free Software Foundation.
+*/
+#ifndef _GLUSTERD_LOCKS_H_
+#define _GLUSTERD_LOCKS_H_
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+struct volume_lock_object_ {
+        uuid_t              lock_owner;
+};
+typedef struct volume_lock_object_ vol_lock_obj;
+
+int32_t
+glusterd_vol_lock_init ();
+
+void
+glusterd_vol_lock_fini ();
+
+int32_t
+glusterd_get_vol_lock_owner (char *volname, uuid_t *uuid);
+
+int32_t
+glusterd_volume_lock (char *volname, uuid_t uuid);
+
+int32_t
+glusterd_volume_unlock (char *volname, uuid_t uuid);
+
+#endif