This is actually pretty easy since fs/dlm already handles the bulk of the
work. The Ocfs2 userspace cluster stack module already uses fs/dlm as the
underlying lock manager, so I only had to add the right calls.
Cluster-aware POSIX locks ("plocks") can be turned off by the same means at
UNIX locks - mount with 'noflocks', or create a local-only Ocfs2 volume.
Internally, the file system uses two sets of file_operations, depending on
whether cluster aware plocks is required. This turns out to be easier than
implementing local-only versions of ->lock.
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
		
	
		
			
				
	
	
		
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			33 lines
		
	
	
		
			1.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* -*- mode: c; c-basic-offset: 8; -*-
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|  * vim: noexpandtab sw=8 ts=8 sts=0:
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|  *
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|  * locks.h
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|  *
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|  * Function prototypes for Userspace file locking support
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|  *
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|  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
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|  *
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|  * This program is free software; you can redistribute it and/or
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|  * modify it under the terms of the GNU General Public
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|  * License as published by the Free Software Foundation; either
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|  * version 2 of the License, or (at your option) any later version.
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|  *
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|  * This program is distributed in the hope that it will be useful,
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|  * but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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|  * General Public License for more details.
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|  *
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|  * You should have received a copy of the GNU General Public
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|  * License along with this program; if not, write to the
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|  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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|  * Boston, MA 021110-1307, USA.
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|  */
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| 
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| #ifndef OCFS2_LOCKS_H
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| #define OCFS2_LOCKS_H
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| 
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| int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl);
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| int ocfs2_lock(struct file *file, int cmd, struct file_lock *fl);
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| 
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| #endif /* OCFS2_LOCKS_H */
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