root/sys/miscfs/deadfs/dead_vfsops.c
/*      $NetBSD: dead_vfsops.c,v 1.13 2022/10/26 23:39:43 riastradh Exp $       */

/*-
 * Copyright (c) 2014 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Juergen Hannken-Illjes.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: dead_vfsops.c,v 1.13 2022/10/26 23:39:43 riastradh Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/mount.h>

#include <miscfs/deadfs/deadfs.h>
#include <miscfs/specfs/specdev.h>

VFS_PROTOS(dead);

static void dead_panic(void);

static const struct vnodeopv_desc * const dead_vnodeopv_descs[] = {
        &dead_vnodeop_opv_desc,
        NULL
};

struct mount *dead_rootmount;

struct vfsops dead_vfsops = {
        .vfs_name = "dead",
        .vfs_min_mount_data = 0,
        .vfs_mount = (void *)dead_panic,
        .vfs_start = (void *)dead_panic,
        .vfs_unmount = (void *)dead_panic,
        .vfs_root = (void *)dead_panic,
        .vfs_quotactl = (void *)dead_panic,
        .vfs_statvfs = (void *)eopnotsupp,
        .vfs_sync = (void *)dead_panic,
        .vfs_vget = (void *)dead_panic,
        .vfs_loadvnode = (void *)dead_panic,
        .vfs_newvnode = dead_newvnode,
        .vfs_fhtovp = (void *)dead_panic,
        .vfs_vptofh = (void *)eopnotsupp,
        .vfs_init = (void *)dead_panic,
        .vfs_reinit = (void *)dead_panic,
        .vfs_done = (void *)dead_panic,
        .vfs_mountroot = (void *)dead_panic,
        .vfs_snapshot = (void *)dead_panic,
        .vfs_extattrctl = (void *)dead_panic,
        .vfs_suspendctl = (void *)dead_panic,
        .vfs_renamelock_enter = (void *)dead_panic,
        .vfs_renamelock_exit = (void *)dead_panic,
        .vfs_fsync = (void *)eopnotsupp,
        .vfs_opv_descs = dead_vnodeopv_descs
};

static void
dead_panic(void)
{

        panic("dead fs operation used");
}

/*
 * Create a new anonymous device vnode.
 */
int
dead_newvnode(struct mount *mp, struct vnode *dvp, struct vnode *vp,
    struct vattr *vap, kauth_cred_t cred, void *extra,
    size_t *key_len, const void **new_key)
{

        KASSERT(mp == dead_rootmount);
        KASSERT(dvp == NULL);
        KASSERT(vap->va_type == VCHR || vap->va_type == VBLK);
        KASSERT(vap->va_rdev != VNOVAL);

        vp->v_tag = VT_NON;
        vp->v_type = vap->va_type;
        vp->v_op = spec_vnodeop_p;
        vp->v_vflag |= VV_MPSAFE;
        uvm_vnp_setsize(vp, 0);
        spec_node_init(vp, vap->va_rdev);

        *key_len = 0;
        *new_key = NULL;

        return 0;
}