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 (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
23 */
24
25 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
26 /* All Rights Reserved */
27
28 /*
29 * University Copyright- Copyright (c) 1982, 1986, 1988
30 * The Regents of the University of California
31 * All Rights Reserved
32 *
33 * University Acknowledgment- Portions of this document are derived from
34 * software developed by the University of California, Berkeley, and its
35 * contributors.
36 */
37
38
39 #include <sys/types.h>
40 #include <sys/t_lock.h>
41 #include <sys/param.h>
42 #include <sys/buf.h>
43 #include <sys/cmn_err.h>
44 #include <sys/debug.h>
45 #include <sys/errno.h>
46 #include <sys/vfs.h>
47 #include <sys/swap.h>
48 #include <sys/vnode.h>
49 #include <sys/cred.h>
50 #include <sys/fs/snode.h>
51 #include <sys/thread.h>
52
53 #include <fs/fs_subr.h>
54
55 /*
56 * This is the loadable module wrapper.
57 */
58 #include <sys/modctl.h>
59
60 static vfsdef_t vfw = {
61 VFSDEF_VERSION,
62 "specfs",
63 specinit,
64 VSW_ZMOUNT,
65 NULL
66 };
67
68 extern struct mod_ops mod_fsops;
69
70 /*
71 * Module linkage information for the kernel.
72 */
73 static struct modlfs modlfs = {
74 &mod_fsops, "filesystem for specfs", &vfw
75 };
76
77 static struct modlinkage modlinkage = {
78 MODREV_1, (void *)&modlfs, NULL
79 };
80
81 int
82 _init(void)
83 {
84 return (mod_install(&modlinkage));
85 }
86
87 int
88 _info(struct modinfo *modinfop)
89 {
90 return (mod_info(&modlinkage, modinfop));
91 }
92
93 /*
94 * N.B.
95 * No _fini routine. This module cannot be unloaded once loaded.
96 * The NO_UNLOAD_STUB in modstub.s must change if this module ever
97 * is modified to become unloadable.
98 */
99
100 kmutex_t spec_syncbusy; /* initialized in specinit() */
101
102 /*
103 * Run though all the snodes and force write-back
104 * of all dirty pages on the block devices.
105 */
106 /*ARGSUSED*/
107 int
108 spec_sync(struct vfs *vfsp,
109 short flag,
110 struct cred *cr)
111 {
112 struct snode *sync_list;
113 register struct snode **spp, *sp, *spnext;
114 register struct vnode *vp;
115
116 if (mutex_tryenter(&spec_syncbusy) == 0)
117 return (0);
118
119 if (flag & SYNC_ATTR) {
120 mutex_exit(&spec_syncbusy);
121 return (0);
122 }
123 mutex_enter(&stable_lock);
124 sync_list = NULL;
125 /*
126 * Find all the snodes that are dirty and add them to the sync_list
127 */
128 for (spp = stable; spp < &stable[STABLESIZE]; spp++) {
129 for (sp = *spp; sp != NULL; sp = sp->s_next) {
130 vp = STOV(sp);
131 /*
132 * Don't bother sync'ing a vp if it's
133 * part of a virtual swap device.
134 */
135 if (IS_SWAPVP(vp))
136 continue;
137
138 if (vp->v_type == VBLK && vn_has_cached_data(vp)) {
139 /*
140 * Prevent vp from going away before we
141 * we get a chance to do a VOP_PUTPAGE
142 * via sync_list processing
143 */
144 VN_HOLD(vp);
145 sp->s_list = sync_list;
146 sync_list = sp;
147 }
148 }
149 }
150 mutex_exit(&stable_lock);
151 /*
152 * Now write out all the snodes we marked asynchronously.
153 */
154 for (sp = sync_list; sp != NULL; sp = spnext) {
155 spnext = sp->s_list;
156 vp = STOV(sp);
157 (void) VOP_PUTPAGE(vp, (offset_t)0, (uint_t)0, B_ASYNC, cr,
158 NULL);
159 VN_RELE(vp); /* Release our hold on vnode */
160 }
161 mutex_exit(&spec_syncbusy);
162 return (0);
163 }