- Promote em(4) polling begin/end ktr into polling(4)

[dragonfly.git] / sys / kern / vfs_init.c

/*
 * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
 * 
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed
 * to Berkeley by John Heidemann of the UCLA Ficus project.
 *
 * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)vfs_init.c  8.3 (Berkeley) 1/4/94
 * $FreeBSD: src/sys/kern/vfs_init.c,v 1.59 2002/04/30 18:44:32 dillon Exp $
 * $DragonFly: src/sys/kern/vfs_init.c,v 1.14 2006/09/05 00:55:45 dillon Exp $
 */
/*
 * Manage vnode VOP operations vectors
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/mount.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/objcache.h>

static MALLOC_DEFINE(M_VNODEOP, "vnodeops", "vnode operations vectors");
static MALLOC_DEFINE(M_NAMEI, "nameibufs", "namei path buffers");

/*
 * Zone for namei
 */
struct objcache *namei_oc;

/*
 * vfs_init() will set maxvfsconf
 * to the highest defined type number.
 */
int maxvfsconf;
struct vfsconf *vfsconf;

static TAILQ_HEAD(, vnodeopv_node) vnodeopv_list;
static void vfs_calc_vnodeops(struct vop_ops *ops);

/*
 * Add a vnode operations (vnops) vector to the global list.
 */
void
vfs_nadd_vnodeops_sysinit(void *data)
{
        struct vop_ops *ops = data;

        vfs_add_vnodeops(NULL, ops, NULL);      /* mount, template, newcopy */
}

/*
 * Unlink previously added vnode operations vector.
 */
void
vfs_nrm_vnodeops_sysinit(void *data)
{
        struct vop_ops *ops = data;

        vfs_rm_vnodeops(NULL, ops, NULL);
}

void
vfs_add_vnodeops(struct mount *mp, struct vop_ops *template,
                 struct vop_ops **ops_pp)
{
        struct vop_ops *ops;

        if (ops_pp) {
                KKASSERT(*ops_pp == NULL);
                *ops_pp = kmalloc(sizeof(*ops), M_VNODEOP, M_WAITOK);
                ops = *ops_pp;
                bcopy(template, ops, sizeof(*ops));
        } else {
                ops = template;
        }

        vfs_calc_vnodeops(ops);
        ops->head.vv_mount = mp;

        if (mp) {
                if (mp->mnt_vn_coherency_ops)
                        mp->mnt_vn_use_ops = mp->mnt_vn_coherency_ops;
                else if (mp->mnt_vn_journal_ops)
                        mp->mnt_vn_use_ops = mp->mnt_vn_journal_ops;
                else
                        mp->mnt_vn_use_ops = mp->mnt_vn_norm_ops;
        }
}

/*
 * Remove a previously installed operations vector.
 *
 * NOTE: Either template or ops_pp may be NULL, but not both.
 */
void
vfs_rm_vnodeops(struct mount *mp, struct vop_ops *template,
                struct vop_ops **ops_pp)
{
        struct vop_ops *ops;

        if (ops_pp) {
                ops = *ops_pp;
                *ops_pp = NULL;
        } else {
                ops = template;
        }
        if (ops == NULL)
                return;
        KKASSERT(mp == ops->head.vv_mount);
        if (mp) {
                if (mp->mnt_vn_coherency_ops)
                        mp->mnt_vn_use_ops = mp->mnt_vn_coherency_ops;
                else if (mp->mnt_vn_journal_ops)
                        mp->mnt_vn_use_ops = mp->mnt_vn_journal_ops;
                else
                        mp->mnt_vn_use_ops = mp->mnt_vn_norm_ops;
        }
        if (ops_pp)
                kfree(ops, M_VNODEOP);
}

/*
 * Calculate the VFS operations vector array.  This function basically
 * replaces any NULL entry with the default entry.
 */
static void
vfs_calc_vnodeops(struct vop_ops *ops)
{
        int off;

        for (off = __offsetof(struct vop_ops, vop_ops_first_field);
             off <= __offsetof(struct vop_ops, vop_ops_last_field);
             off += sizeof(void *)
        ) {
                if (*(void **)((char *)ops + off) == NULL)
                    *(void **)((char *)ops + off) = ops->vop_default;
        }
}

/*
 * Routines having to do with the management of the vnode table.
 */
struct vattr va_null;

/*
 * Initialize the vnode structures and initialize each file system type.
 */
/* ARGSUSED*/
static void
vfsinit(void *dummy)
{
        TAILQ_INIT(&vnodeopv_list);
        namei_oc = objcache_create_simple(M_NAMEI, MAXPATHLEN);

        /*
         * Initialize the vnode table
         */
        vfs_subr_init();
        vfs_mount_init();
        vfs_lock_init();
        vfs_sync_init();
        /*
         * Initialize the vnode name cache
         */
        nchinit();
        /*
         * Initialize each file system type.
         * Vfs type numbers must be distinct from VFS_GENERIC (and VFS_VFSCONF).
         */
        vattr_null(&va_null);
        maxvfsconf = VFS_GENERIC + 1;
}
SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vfsinit, NULL)

/*
 * Register a VFS.
 *
 * After doing general initialisation, this function will
 * call the filesystem specific initialisation vector op,
 * i.e. vfsops->vfs_init().
 */
int
vfs_register(struct vfsconf *vfc)
{
        struct sysctl_oid *oidp;
        struct vfsconf *vfsp;
        struct vfsops *vfsops = NULL;

        vfsp = NULL;
        if (vfsconf)
                for (vfsp = vfsconf; vfsp->vfc_next; vfsp = vfsp->vfc_next)
                        if (strcmp(vfc->vfc_name, vfsp->vfc_name) == 0)
                                return EEXIST;

        vfc->vfc_typenum = maxvfsconf++;
        if (vfsp)
                vfsp->vfc_next = vfc;
        else
                vfsconf = vfc;
        vfc->vfc_next = NULL;

        /*
         * If this filesystem has a sysctl node under vfs
         * (i.e. vfs.xxfs), then change the oid number of that node to 
         * match the filesystem's type number.  This allows user code
         * which uses the type number to read sysctl variables defined
         * by the filesystem to continue working. Since the oids are
         * in a sorted list, we need to make sure the order is
         * preserved by re-registering the oid after modifying its
         * number.
         */
        SLIST_FOREACH(oidp, &sysctl__vfs_children, oid_link)
                if (strcmp(oidp->oid_name, vfc->vfc_name) == 0) {
                        sysctl_unregister_oid(oidp);
                        oidp->oid_number = vfc->vfc_typenum;
                        sysctl_register_oid(oidp);
                }
        
        /*
         * Initialise unused fields in the file system's vfsops vector.
         *
         * NOTE the file system should provide the mount and unmount ops
         * at the least.  In order for unmount to succeed, we also need
         * the file system to provide us with vfsops->vfs_root otherwise
         * the unmount(2) operation will not succeed.
         */
        vfsops = vfc->vfc_vfsops;
        KKASSERT(vfc->vfc_vfsops != NULL);
        KKASSERT(vfsops->vfs_mount != NULL);
        KKASSERT(vfsops->vfs_root != NULL);
        KKASSERT(vfsops->vfs_unmount != NULL);

        if (vfsops->vfs_root == NULL) {
                /* return file system's root vnode */
                vfsops->vfs_root = vfs_stdroot;
        }
        if (vfsops->vfs_start == NULL) {
                /* 
                 * Make file system operational before first use.  This
                 * routine is called at mount-time for initialising MFS,
                 * not used by other file systems.
                 */
                vfsops->vfs_start = vfs_stdstart;
        }
        if (vfsops->vfs_quotactl == NULL) {
                /* quota control */
                vfsops->vfs_quotactl = vfs_stdquotactl;
        }
        if (vfsops->vfs_statfs == NULL) {
                /* return file system's status */
                vfsops->vfs_statfs = vfs_stdstatfs;
        }
        if (vfsops->vfs_sync == NULL) {
                /*
                 * Flush dirty buffers.  File systems can use vfs_stdsync()
                 * by explicitly setting it in the vfsops->vfs_sync vector
                 * entry.
                 */
                vfsops->vfs_sync = vfs_stdnosync;
        }
        if (vfsops->vfs_vget == NULL) {
                /* convert an inode number to a vnode */
                vfsops->vfs_vget = vfs_stdvget;
        }
        if (vfsops->vfs_fhtovp == NULL) {
                /* turn an NFS file handle into a vnode */
                vfsops->vfs_fhtovp = vfs_stdfhtovp;
        }
        if (vfsops->vfs_checkexp == NULL) {
                /* check if file system is exported */
                vfsops->vfs_checkexp = vfs_stdcheckexp;
        }
        if (vfsops->vfs_vptofh == NULL) {
                /* turn a vnode into an NFS file handle */
                vfsops->vfs_vptofh = vfs_stdvptofh;
        }
        if (vfsops->vfs_init == NULL) {
                /* file system specific initialisation */
                vfsops->vfs_init = vfs_stdinit;
        }
        if (vfsops->vfs_uninit == NULL) {
                /* file system specific uninitialisation */
                vfsops->vfs_uninit = vfs_stduninit;
        }
        if (vfsops->vfs_extattrctl == NULL) {
                /* extended attribute control */
                vfsops->vfs_extattrctl = vfs_stdextattrctl;
        }

        /*
         * Call init function for this VFS...
         */
        (*(vfc->vfc_vfsops->vfs_init))(vfc);

        return 0;
}


/*
 * Remove previously registered VFS.
 *
 * After doing general de-registration like removing sysctl
 * nodes etc, it will call the filesystem specific vector
 * op, i.e. vfsops->vfs_uninit().
 * 
 */
int
vfs_unregister(struct vfsconf *vfc)
{
        struct vfsconf *vfsp, *prev_vfsp;
        int error, i, maxtypenum;

        i = vfc->vfc_typenum;

        prev_vfsp = NULL;
        for (vfsp = vfsconf; vfsp;
                        prev_vfsp = vfsp, vfsp = vfsp->vfc_next) {
                if (!strcmp(vfc->vfc_name, vfsp->vfc_name))
                        break;
        }
        if (vfsp == NULL)
                return EINVAL;
        if (vfsp->vfc_refcount)
                return EBUSY;
        if (vfc->vfc_vfsops->vfs_uninit != NULL) {
                error = (*vfc->vfc_vfsops->vfs_uninit)(vfsp);
                if (error)
                        return (error);
        }
        if (prev_vfsp)
                prev_vfsp->vfc_next = vfsp->vfc_next;
        else
                vfsconf = vfsp->vfc_next;
        maxtypenum = VFS_GENERIC;
        for (vfsp = vfsconf; vfsp != NULL; vfsp = vfsp->vfc_next)
                if (maxtypenum < vfsp->vfc_typenum)
                        maxtypenum = vfsp->vfc_typenum;
        maxvfsconf = maxtypenum + 1;
        return 0;
}

int
vfs_modevent(module_t mod, int type, void *data)
{
        struct vfsconf *vfc;
        int error = 0;

        vfc = (struct vfsconf *)data;

        switch (type) {
        case MOD_LOAD:
                if (vfc)
                        error = vfs_register(vfc);
                break;

        case MOD_UNLOAD:
                if (vfc)
                        error = vfs_unregister(vfc);
                break;
        default:        /* including MOD_SHUTDOWN */
                break;
        }
        return (error);
}