linux/fs/ocfs2/ocfs2_lockingver.h

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * ocfs2_lockingver.h
 *
 * Defines OCFS2 Locking version values.
 *
 * Copyright (C) 2008 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License, version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */

#ifndef OCFS2_LOCKINGVER_H
#define OCFS2_LOCKINGVER_H

/*
 * The protocol version for ocfs2 cluster locking.  See dlmglue.c for
 * more details.
 */
#define OCFS2_LOCKING_PROTOCOL_MAJOR 1
#define OCFS2_LOCKING_PROTOCOL_MINOR 0

#endif  /* OCFS2_LOCKINGVER_H */
ocfs2: Negotiate locking protocol versions. Currently, when ocfs2 nodes connect via TCP, they advertise their compatibility level. If the versions do not match, two nodes cannot speak to each other and they disconnect. As a result, this provides no forward or backwards compatibility. This patch implements a simple protocol negotiation at the dlm level by introducing a major/minor version number scheme for entities that communicate. Specifically, o2dlm has a major/minor version for interaction with o2dlm on other nodes, and ocfs2 itself has a major/minor version for interacting with the filesystem on other nodes. This will allow rolling upgrades of ocfs2 clusters when changes to the locking or network protocols can be done in a backwards compatible manner. In those cases, only the minor number is changed and the negotatied protocol minor is returned from dlm join. In the far less likely event that a required protocol change makes backwards compatibility impossible, we simply bump the major number. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com> 2008-01-26 09:02:21 +08:00			`/* -- mode: c; c-basic-offset: 8; --`
			`* vim: noexpandtab sw=8 ts=8 sts=0:`
			`*`
			`* ocfs2_lockingver.h`
			`*`
			`* Defines OCFS2 Locking version values.`
			`*`
			`* Copyright (C) 2008 Oracle. All rights reserved.`
			`*`
			`* This program is free software; you can redistribute it and/or`
			`* modify it under the terms of the GNU General Public`
			`* License, version 2, as published by the Free Software Foundation.`
			`*`
			`* This program is distributed in the hope that it will be useful,`
			`* but WITHOUT ANY WARRANTY; without even the implied warranty of`
			`* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU`
			`* General Public License for more details.`
			`*/`

			`#ifndef OCFS2_LOCKINGVER_H`
			`#define OCFS2_LOCKINGVER_H`

			`/*`
			`* The protocol version for ocfs2 cluster locking. See dlmglue.c for`
			`* more details.`
			`*/`
			`#define OCFS2_LOCKING_PROTOCOL_MAJOR 1`
			`#define OCFS2_LOCKING_PROTOCOL_MINOR 0`

			`#endif /* OCFS2_LOCKINGVER_H */`