1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright (c) 2000 by Sun Microsystems, Inc.
24 * All rights reserved.
25 */
26
27#ifndef	DSVCD_CONTAINER_H
28#define	DSVCD_CONTAINER_H
29
30#pragma ident	"%Z%%M%	%I%	%E% SMI"
31
32#include <sys/types.h>
33#include <synch.h>
34
35#include "dsvclockd.h"
36
37/*
38 * Container-related data structures, functions and constants.  See
39 * comments in container.c for a description of how to use the exported
40 * functions.
41 */
42
43#ifdef	__cplusplus
44extern "C" {
45#endif
46
47/*
48 * Number of seconds to wait for container lockholders to relinquish all
49 * locks on a given container (when it's being destroyed).
50 */
51#define	CN_DESTROY_WAIT	60
52
53/*
54 * Describes a thread waiting to access a given container; exactly one per
55 * waiting thread.
56 */
57typedef struct dsvcd_waitlist {
58	struct dsvcd_waitlist	*wl_next;	/* next waiter in list */
59	struct dsvcd_waitlist	*wl_prev;	/* prev waiter in list */
60	cond_t			wl_cv;		/* our condition variable */
61	dsvcd_locktype_t	wl_locktype;	/* type of lock we want */
62} dsvcd_waitlist_t;
63
64/*
65 * States for the host lock state machine.  The state machine is a simple
66 * cycle of UNLOCKED->PENDING->{RD,WR}LOCKED->UNLOCKED->...
67 */
68enum cn_hlockstate { CN_HUNLOCKED, CN_HPENDING, CN_HRDLOCKED, CN_HWRLOCKED };
69
70/*
71 * Describes a given container within a datastore.  There is at most one of
72 * these per datastore container (there may be none if there are no current
73 * consumers of a given container within a datastore).  If there is more
74 * than one open handle to a given container (through multiple calls to
75 * open_d?()) there will still only be one dsvcd_container_t for that
76 * container.  This object is used to synchronize access to an underlying
77 * container through use of its custom reader/writer lock (it can't use the
78 * rwlock_t's built into Solaris because we need locks that do not care if
79 * the unlocking thread is the same as the locking thread).  It also
80 * contains other per-container information like the container id.
81 */
82typedef struct dsvcd_container {
83	char			*cn_id;		/* container's id */
84	boolean_t		cn_crosshost;	/* synchronize across hosts */
85	boolean_t		cn_closing;	/* container is going away */
86	mutex_t			cn_lock;	/* protects preceding fields */
87
88	dsvcd_waitlist_t	*cn_whead;	/* head of wait list */
89	dsvcd_waitlist_t	*cn_wtail;	/* tail of wait list */
90	int			cn_nholds;	/* num readers (-1 == writer) */
91	mutex_t			cn_nholds_lock;	/* for nholds and waitlist */
92
93	int			cn_hlockfd;	/* host lock file descriptor */
94	int			cn_hlockcount;	/* current # of host locks */
95	enum cn_hlockstate	cn_hlockstate;	/* host lock state */
96	cond_t			cn_hlockcv;	/* host lock condvar */
97	mutex_t			cn_hlock_lock;	/* mutex for cn_hlock* */
98
99	/*
100	 * These fields are used to keep metadata state regarding the
101	 * container and are actually maintained by the containing
102	 * datastore, not the container.
103	 */
104	uint_t			cn_nout;	/* number checked out */
105	time_t			cn_lastrel;	/* last released */
106	uint32_t		cn_idhash;	/* hash before modulation */
107	struct dsvcd_container	*cn_next;	/* hash chain next */
108	struct dsvcd_container	*cn_prev;	/* hash chain prev */
109} dsvcd_container_t;
110
111extern dsvcd_container_t	*cn_create(const char *, boolean_t);
112extern void			cn_destroy(dsvcd_container_t *);
113extern int			cn_rdlock(dsvcd_container_t *, boolean_t);
114extern int			cn_wrlock(dsvcd_container_t *, boolean_t);
115extern int			cn_unlock(dsvcd_container_t *);
116extern dsvcd_locktype_t		cn_locktype(dsvcd_container_t *);
117
118#ifdef	__cplusplus
119}
120#endif
121
122#endif	/* DSVCD_CONTAINER_H */
123