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
44 extern "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 */
57 typedef 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 */
68 enum 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 */
82 typedef 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
111 extern dsvcd_container_t *cn_create(const char *, boolean_t);
112 extern void cn_destroy(dsvcd_container_t *);
113 extern int cn_rdlock(dsvcd_container_t *, boolean_t);
114 extern int cn_wrlock(dsvcd_container_t *, boolean_t);
115 extern int cn_unlock(dsvcd_container_t *);
116 extern dsvcd_locktype_t cn_locktype(dsvcd_container_t *);
117
118 #ifdef __cplusplus
119 }
120 #endif
121
122 #endif /* DSVCD_CONTAINER_H */