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      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 2007 Sun Microsystems, Inc.  All rights reserved.
     23  * Use is subject to license terms.
     24  */
     25 
     26 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
     27 /*	  All Rights Reserved  	*/
     28 
     29 /*
     30  * University Copyright- Copyright (c) 1982, 1986, 1988
     31  * The Regents of the University of California
     32  * All Rights Reserved
     33  *
     34  * University Acknowledgment- Portions of this document are derived from
     35  * software developed by the University of California, Berkeley, and its
     36  * contributors.
     37  */
     38 
     39 
     40 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     41 
     42 #include <sys/types.h>
     43 #include <sys/t_lock.h>
     44 #include <sys/param.h>
     45 #include <sys/buf.h>
     46 #include <sys/cmn_err.h>
     47 #include <sys/debug.h>
     48 #include <sys/errno.h>
     49 #include <sys/vfs.h>
     50 #include <sys/swap.h>
     51 #include <sys/vnode.h>
     52 #include <sys/cred.h>
     53 #include <sys/fs/snode.h>
     54 #include <sys/thread.h>
     55 
     56 #include <fs/fs_subr.h>
     57 
     58 /*
     59  * This is the loadable module wrapper.
     60  */
     61 #include <sys/modctl.h>
     62 
     63 static vfsdef_t vfw = {
     64 	VFSDEF_VERSION,
     65 	"specfs",
     66 	specinit,
     67 	0,
     68 	NULL
     69 };
     70 
     71 extern struct mod_ops mod_fsops;
     72 
     73 /*
     74  * Module linkage information for the kernel.
     75  */
     76 static struct modlfs modlfs = {
     77 	&mod_fsops, "filesystem for specfs", &vfw
     78 };
     79 
     80 static struct modlinkage modlinkage = {
     81 	MODREV_1, (void *)&modlfs, NULL
     82 };
     83 
     84 int
     85 _init(void)
     86 {
     87 	return (mod_install(&modlinkage));
     88 }
     89 
     90 int
     91 _info(struct modinfo *modinfop)
     92 {
     93 	return (mod_info(&modlinkage, modinfop));
     94 }
     95 
     96 /*
     97  * N.B.
     98  * No _fini routine. This module cannot be unloaded once loaded.
     99  * The NO_UNLOAD_STUB in modstub.s must change if this module ever
    100  * is modified to become unloadable.
    101  */
    102 
    103 kmutex_t spec_syncbusy;		/* initialized in specinit() */
    104 
    105 /*
    106  * Run though all the snodes and force write-back
    107  * of all dirty pages on the block devices.
    108  */
    109 /*ARGSUSED*/
    110 int
    111 spec_sync(struct vfs *vfsp,
    112 	short	flag,
    113 	struct cred *cr)
    114 {
    115 	struct snode *sync_list;
    116 	register struct snode **spp, *sp, *spnext;
    117 	register struct vnode *vp;
    118 
    119 	if (mutex_tryenter(&spec_syncbusy) == 0)
    120 		return (0);
    121 
    122 	if (flag & SYNC_ATTR) {
    123 		mutex_exit(&spec_syncbusy);
    124 		return (0);
    125 	}
    126 	mutex_enter(&stable_lock);
    127 	sync_list = NULL;
    128 	/*
    129 	 * Find all the snodes that are dirty and add them to the sync_list
    130 	 */
    131 	for (spp = stable; spp < &stable[STABLESIZE]; spp++) {
    132 		for (sp = *spp; sp != NULL; sp = sp->s_next) {
    133 			vp = STOV(sp);
    134 			/*
    135 			 * Don't bother sync'ing a vp if it's
    136 			 * part of a virtual swap device.
    137 			 */
    138 			if (IS_SWAPVP(vp))
    139 				continue;
    140 
    141 			if (vp->v_type == VBLK && vn_has_cached_data(vp)) {
    142 				/*
    143 				 * Prevent vp from going away before we
    144 				 * we get a chance to do a VOP_PUTPAGE
    145 				 * via sync_list processing
    146 				 */
    147 				VN_HOLD(vp);
    148 				sp->s_list = sync_list;
    149 				sync_list = sp;
    150 			}
    151 		}
    152 	}
    153 	mutex_exit(&stable_lock);
    154 	/*
    155 	 * Now write out all the snodes we marked asynchronously.
    156 	 */
    157 	for (sp = sync_list; sp != NULL; sp = spnext) {
    158 		spnext = sp->s_list;
    159 		vp = STOV(sp);
    160 		(void) VOP_PUTPAGE(vp, (offset_t)0, (uint_t)0, B_ASYNC, cr,
    161 		    NULL);
    162 		VN_RELE(vp);		/* Release our hold on vnode */
    163 	}
    164 	mutex_exit(&spec_syncbusy);
    165 	return (0);
    166 }
    167