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
60static vfsdef_t vfw = {
61	VFSDEF_VERSION,
62	"specfs",
63	specinit,
64	VSW_ZMOUNT,
65	NULL
66};
67
68extern struct mod_ops mod_fsops;
69
70/*
71 * Module linkage information for the kernel.
72 */
73static struct modlfs modlfs = {
74	&mod_fsops, "filesystem for specfs", &vfw
75};
76
77static struct modlinkage modlinkage = {
78	MODREV_1, (void *)&modlfs, NULL
79};
80
81int
82_init(void)
83{
84	return (mod_install(&modlinkage));
85}
86
87int
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
100kmutex_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*/
107int
108spec_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}
164