386BSD 0.1 development
[unix-history] / usr / src / sys.386bsd / ufs / lockf.h
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1/*
2 * Copyright (c) 1991 The Regents of the University of California.
3 * 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 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)lockf.h 7.1 (Berkeley) 2/1/91
37 */
38
39/*
40 * The lockf structure is a kernel structure which contains all the
41 * information associated with a byte range lock. The lockf structures
42 * are linked into the inode structure. Locks are sorted by the starting
43 * byte of the lock for efficiency.
44 */
45struct lockf {
46 short lf_flags; /* Lock semantics: F_POSIX, F_FLOCK, F_WAIT */
47 short lf_type; /* Lock type: F_RDLCK, F_WRLCK */
48 off_t lf_start; /* The byte # of the start of the lock */
49 off_t lf_end; /* The byte # of the end of the lock (-1=EOF)*/
50 caddr_t lf_id; /* The id of the resource holding the lock */
51 struct inode *lf_inode; /* Back pointer to the inode */
52 struct lockf *lf_next; /* A pointer to the next lock on this inode */
53 struct lockf *lf_block; /* The list of blocked locks */
54};
55
56/*
57 * Maximum length of sleep chains to traverse to try and detect deadlock.
58 */
59#define MAXDEPTH 50
60
61#ifdef KERNEL
62/*
63 * Public lock manipulation routines
64 */
65extern struct lockf *lf_remove(); /* Remove a lock */
66extern struct lockf *lf_getblock(); /* Return the first blocking lock */
67
68#ifdef LOCKF_DEBUG
69extern int lockf_debug;
70#endif LOCKF_DEBUG
71#endif KERNEL