NetBSD/sys/ufs/lockf.h

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1993-03-21 12:45:37 +03:00
/*
* Copyright (c) 1991 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Scooter Morris at Genentech Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)lockf.h 7.1 (Berkeley) 2/1/91
* $Id: lockf.h,v 1.4 1993/05/22 09:01:13 cgd Exp $
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*/
#ifndef _UFS_LOCKF_H_
#define _UFS_LOCKF_H_
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/*
* The lockf structure is a kernel structure which contains all the
* information associated with a byte range lock. The lockf structures
* are linked into the inode structure. Locks are sorted by the starting
* byte of the lock for efficiency.
*/
struct lockf {
short lf_flags; /* Lock semantics: F_POSIX, F_FLOCK, F_WAIT */
short lf_type; /* Lock type: F_RDLCK, F_WRLCK */
off_t lf_start; /* The byte # of the start of the lock */
off_t lf_end; /* The byte # of the end of the lock (-1=EOF)*/
caddr_t lf_id; /* The id of the resource holding the lock */
struct lockf **lf_head; /* Back pointer to the head of lockf list */
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struct lockf *lf_next; /* A pointer to the next lock on this inode */
struct lockf *lf_block; /* The list of blocked locks */
};
/*
* Maximum length of sleep chains to traverse to try and detect deadlock.
*/
#define MAXDEPTH 50
#ifdef KERNEL
/*
* Public lock manipulation routines
*/
extern struct lockf *lf_remove(); /* Remove a lock */
extern struct lockf *lf_getblock(); /* Return the first blocking lock */
#ifdef LOCKF_DEBUG
extern int lockf_debug;
#endif LOCKF_DEBUG
#endif KERNEL
#endif /* !_UFS_LOCKF_H_ */