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lockf.h
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lockf.h
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/* $NetBSD: lockf.h,v 1.14 2003/08/07 16:34:07 agc Exp $ */
/*
* Copyright (c) 1991, 1993
* 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. 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.
*
* @(#)lockf.h 8.2 (Berkeley) 10/26/94
*/
#ifndef _SYS_LOCKF_H_
#define _SYS_LOCKF_H_
/*
* The lockf structure is a kernel structure which contains 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.
*
* lf_next is used for two purposes, depending on whether the lock is
* being held, or is in conflict with an existing lock. If this lock
* is held, it indicates the next lock on the same vnode.
* For pending locks, if lock->lf_next is non-NULL, then lock->lf_block
* must be queued on the lf_blkhd TAILQ of lock->lf_next.
*/
TAILQ_HEAD(locklist, lockf);
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)*/
void *lf_id; /* process or file description holding lock */
struct lwp *lf_lwp; /* LWP waiting for lock */
struct lockf **lf_head; /* Back pointer to the head of lockf list */
struct lockf *lf_next; /* Next lock on this vnode, or blocking lock */
struct locklist lf_blkhd; /* List of requests blocked on this lock */
TAILQ_ENTRY(lockf) lf_block;/* A request waiting for a lock */
};
/* Maximum length of sleep chains to traverse to try and detect deadlock. */
#define MAXDEPTH 50
#ifdef _KERNEL
int lf_advlock(struct vop_advlock_args *, struct lockf **, off_t);
#endif /* _KERNEL */
#endif /* !_SYS_LOCKF_H_ */