fs/specfs/specvfsops.c

	specvfsops.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*  Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */

/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California
 * All Rights Reserved
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */


#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/types.h>
#include <sys/t_lock.h>
#include <sys/param.h>
#include <sys/buf.h>
#include <sys/cmn_err.h>
#include <sys/debug.h>
#include <sys/errno.h>
#include <sys/vfs.h>
#include <sys/swap.h>
#include <sys/vnode.h>
#include <sys/cred.h>
#include <sys/fs/snode.h>
#include <sys/thread.h>

#include <fs/fs_subr.h>

/*
 * This is the loadable module wrapper.
 */
#include <sys/modctl.h>

static vfsdef_t vfw = {
    VFSDEF_VERSION,
    "specfs",
    specinit,
    0,
    NULL
};

extern struct mod_ops mod_fsops;

/*
 * Module linkage information for the kernel.
 */
static struct modlfs modlfs = {
    &mod_fsops, "filesystem for specfs", &vfw
};

static struct modlinkage modlinkage = {
    MODREV_1, (void *)&modlfs, NULL
};

int
_init(void)
{
    return (mod_install(&modlinkage));
}

int
_info(struct modinfo *modinfop)
{
    return (mod_info(&modlinkage, modinfop));
}

/*
 * N.B.
 * No _fini routine. This module cannot be unloaded once loaded.
 * The NO_UNLOAD_STUB in modstub.s must change if this module ever
 * is modififed to become unloadable.
 */

kmutex_t spec_syncbusy;     /* initialized in specinit() */

/*
 * Run though all the snodes and force write-back
 * of all dirty pages on the block devices.
 */
/*ARGSUSED*/
int
spec_sync(struct vfs *vfsp,
    short   flag,
    struct cred *cr)
{
    struct snode *sync_list;
    register struct snode **spp, *sp, *spnext;
    register struct vnode *vp;

    if (mutex_tryenter(&spec_syncbusy) == 0)
        return (0);

    if (flag & SYNC_ATTR) {
        mutex_exit(&spec_syncbusy);
        return (0);
    }
    mutex_enter(&stable_lock);
    sync_list = NULL;
    /*
     * Find all the snodes that are dirty and add them to the sync_list
     */
    for (spp = stable; spp < &stable[STABLESIZE]; spp++) {
        for (sp = *spp; sp != NULL; sp = sp->s_next) {
            vp = STOV(sp);
            /*
             * Don't bother sync'ing a vp if it's
             * part of a virtual swap device.
             */
            if (IS_SWAPVP(vp))
                continue;

            if (vp->v_type == VBLK && vn_has_cached_data(vp)) {
                /*
                 * Prevent vp from going away before we
                 * we get a chance to do a VOP_PUTPAGE
                 * via sync_list processing
                 */
                VN_HOLD(vp);
                sp->s_list = sync_list;
                sync_list = sp;
            }
        }
    }
    mutex_exit(&stable_lock);
    /*
     * Now write out all the snodes we marked asynchronously.
     */
    for (sp = sync_list; sp != NULL; sp = spnext) {
        spnext = sp->s_list;
        vp = STOV(sp);
        (void) VOP_PUTPAGE(vp, (offset_t)0, (uint_t)0, B_ASYNC, cr);
        VN_RELE(vp);        /* Release our hold on vnode */
    }
    mutex_exit(&spec_syncbusy);
    return (0);
}