lockf.h revision 169660 
1/*-
2 * Copyright (c) 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Scooter Morris at Genentech Inc.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 *	@(#)lockf.h	8.1 (Berkeley) 6/11/93
33 * $FreeBSD: head/sys/sys/lockf.h 169660 2007-05-17 16:03:14Z csjp $
34 */
35
36#ifndef _SYS_LOCKF_H_
37#define	_SYS_LOCKF_H_
38
39#include <sys/queue.h>
40
41struct vop_advlock_args;
42
43/*
44 * The lockf structure is a kernel structure which contains the information
45 * associated with a byte range lock.  The lockf structures are linked into
46 * the inode structure. Locks are sorted by the starting byte of the lock for
47 * efficiency.
48 */
49TAILQ_HEAD(locklist, lockf);
50
51struct lockf {
52	short	lf_flags;	    /* Semantics: F_POSIX, F_FLOCK, F_WAIT */
53	short	lf_type;	    /* Lock type: F_RDLCK, F_WRLCK */
54	off_t	lf_start;	    /* Byte # of the start of the lock */
55	off_t	lf_end;		    /* Byte # of the end of the lock (-1=EOF) */
56	caddr_t	lf_id;		    /* Id of the resource holding the lock */
57	struct	lockf **lf_head;    /* Back pointer to the head of the lockf list */
58	struct	inode *lf_inode;    /* Back pointer to the inode */
59	struct	lockf *lf_next;	    /* Pointer to the next lock on this inode */
60	struct	locklist lf_blkhd;  /* List of requests blocked on this lock */
61	TAILQ_ENTRY(lockf) lf_block;/* A request waiting for a lock */
62};
63
64/* Maximum length of sleep chains to traverse to try and detect deadlock. */
65#define MAXDEPTH 50
66
67int	 lf_advlock(struct vop_advlock_args *, struct lockf **, u_quad_t);
68
69#endif /* !_SYS_LOCKF_H_ */
70