/*      $NetBSD: tmpfs_vfsops.c,v 1.10 2005/12/11 12:24:29 christos Exp $       */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2005 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Julio M. Merino Vidal, developed as part of Google's Summer of Code
 * 2005 program.
 *
 * 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.
 */

/*
 * Efficient memory file system.
 *
 * tmpfs is a file system that uses FreeBSD's virtual memory
 * sub-system to store file data and metadata in an efficient way.
 * This means that it does not follow the structure of an on-disk file
 * system because it simply does not need to.  Instead, it uses
 * memory-specific data structures and algorithms to automatically
 * allocate and release resources.
 */

#include "opt_ddb.h"
#include "opt_tmpfs.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/dirent.h>
#include <sys/file.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/rwlock.h>
#include <sys/stat.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_extern.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_param.h>

#include <fs/tmpfs/tmpfs.h>

/*
 * Default permission for root node
 */
#define TMPFS_DEFAULT_ROOT_MODE (S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)

static MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures");
MALLOC_DEFINE(M_TMPFSNAME, "tmpfs name", "tmpfs file names");

static int      tmpfs_mount(struct mount *);
static int      tmpfs_unmount(struct mount *, int);
static int      tmpfs_root(struct mount *, int flags, struct vnode **);
static int      tmpfs_fhtovp(struct mount *, struct fid *, int,
                    struct vnode **);
static int      tmpfs_statfs(struct mount *, struct statfs *);

static const char *tmpfs_opts[] = {
        "from", "easize", "size", "maxfilesize", "inodes", "uid", "gid", "mode",
        "export", "union", "nonc", "nomtime", "nosymfollow", "pgread", NULL
};

static const char *tmpfs_updateopts[] = {
        "from", "easize", "export", "nomtime", "size", "nosymfollow", NULL
};

static int
tmpfs_update_mtime_lazy_filter(struct vnode *vp, void *arg)
{
        struct vm_object *obj;

        if (vp->v_type != VREG)
                return (0);

        obj = atomic_load_ptr(&vp->v_object);
        if (obj == NULL)
                return (0);

        return (vm_object_mightbedirty_(obj));
}

static void
tmpfs_update_mtime_lazy(struct mount *mp)
{
        struct vnode *vp, *mvp;

        MNT_VNODE_FOREACH_LAZY(vp, mp, mvp, tmpfs_update_mtime_lazy_filter, NULL) {
                if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK) != 0)
                        continue;
                tmpfs_check_mtime(vp);
                vput(vp);
        }
}

static void
tmpfs_update_mtime_all(struct mount *mp)
{
        struct vnode *vp, *mvp;

        if (VFS_TO_TMPFS(mp)->tm_nomtime)
                return;
        MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
                if (vp->v_type != VREG) {
                        VI_UNLOCK(vp);
                        continue;
                }
                if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK) != 0)
                        continue;
                tmpfs_check_mtime(vp);
                tmpfs_update(vp);
                vput(vp);
        }
}

struct tmpfs_check_rw_maps_arg {
        bool found;
};

static bool
tmpfs_check_rw_maps_cb(struct mount *mp __unused, vm_map_t map __unused,
    vm_map_entry_t entry __unused, void *arg)
{
        struct tmpfs_check_rw_maps_arg *a;

        a = arg;
        a->found = true;
        return (true);
}

/*
 * Revoke write permissions from all mappings of regular files
 * belonging to the specified tmpfs mount.
 */
static bool
tmpfs_revoke_rw_maps_cb(struct mount *mp __unused, vm_map_t map,
    vm_map_entry_t entry, void *arg __unused)
{

        /*
         * XXXKIB: might be invalidate the mapping
         * instead ?  The process is not going to be
         * happy in any case.
         */
        entry->max_protection &= ~VM_PROT_WRITE;
        if ((entry->protection & VM_PROT_WRITE) != 0) {
                entry->protection &= ~VM_PROT_WRITE;
                pmap_protect(map->pmap, entry->start, entry->end,
                    entry->protection);
        }
        return (false);
}

static void
tmpfs_all_rw_maps(struct mount *mp, bool (*cb)(struct mount *mp, vm_map_t,
    vm_map_entry_t, void *), void *cb_arg)
{
        struct proc *p;
        struct vmspace *vm;
        vm_map_t map;
        vm_map_entry_t entry;
        vm_object_t object;
        struct vnode *vp;
        int gen;
        bool terminate;

        terminate = false;
        sx_slock(&allproc_lock);
again:
        gen = allproc_gen;
        FOREACH_PROC_IN_SYSTEM(p) {
                PROC_LOCK(p);
                if (p->p_state != PRS_NORMAL || (p->p_flag & (P_INEXEC |
                    P_SYSTEM | P_WEXIT)) != 0) {
                        PROC_UNLOCK(p);
                        continue;
                }
                vm = vmspace_acquire_ref(p);
                _PHOLD(p);
                PROC_UNLOCK(p);
                if (vm == NULL) {
                        PRELE(p);
                        continue;
                }
                sx_sunlock(&allproc_lock);
                map = &vm->vm_map;

                vm_map_lock(map);
                if (map->busy)
                        vm_map_wait_busy(map);
                VM_MAP_ENTRY_FOREACH(entry, map) {
                        if ((entry->eflags & (MAP_ENTRY_GUARD |
                            MAP_ENTRY_IS_SUB_MAP | MAP_ENTRY_COW)) != 0 ||
                            (entry->max_protection & VM_PROT_WRITE) == 0)
                                continue;
                        object = entry->object.vm_object;
                        if (object == NULL || object->type != tmpfs_pager_type)
                                continue;
                        /*
                         * No need to dig into shadow chain, mapping
                         * of the object not at top is readonly.
                         */

                        VM_OBJECT_RLOCK(object);
                        if (object->type == OBJT_DEAD) {
                                VM_OBJECT_RUNLOCK(object);
                                continue;
                        }
                        MPASS(object->ref_count > 1);
                        if ((object->flags & OBJ_TMPFS) == 0) {
                                VM_OBJECT_RUNLOCK(object);
                                continue;
                        }
                        vp = VM_TO_TMPFS_VP(object);
                        if (vp->v_mount != mp) {
                                VM_OBJECT_RUNLOCK(object);
                                continue;
                        }

                        terminate = cb(mp, map, entry, cb_arg);
                        VM_OBJECT_RUNLOCK(object);
                        if (terminate)
                                break;
                }
                vm_map_unlock(map);

                vmspace_free(vm);
                sx_slock(&allproc_lock);
                PRELE(p);
                if (terminate)
                        break;
        }
        if (!terminate && gen != allproc_gen)
                goto again;
        sx_sunlock(&allproc_lock);
}

static bool
tmpfs_check_rw_maps(struct mount *mp)
{
        struct tmpfs_check_rw_maps_arg ca;

        ca.found = false;
        tmpfs_all_rw_maps(mp, tmpfs_check_rw_maps_cb, &ca);
        return (ca.found);
}

static int
tmpfs_rw_to_ro(struct mount *mp)
{
        int error, flags;
        bool forced;

        forced = (mp->mnt_flag & MNT_FORCE) != 0;
        flags = WRITECLOSE | (forced ? FORCECLOSE : 0);

        if ((error = vn_start_write(NULL, &mp, V_WAIT)) != 0)
                return (error);
        error = vfs_write_suspend_umnt(mp);
        if (error != 0)
                return (error);
        if (!forced && tmpfs_check_rw_maps(mp)) {
                error = EBUSY;
                goto out;
        }
        VFS_TO_TMPFS(mp)->tm_ronly = 1;
        MNT_ILOCK(mp);
        mp->mnt_flag |= MNT_RDONLY;
        MNT_IUNLOCK(mp);
        for (;;) {
                tmpfs_all_rw_maps(mp, tmpfs_revoke_rw_maps_cb, NULL);
                tmpfs_update_mtime_all(mp);
                error = vflush(mp, 0, flags, curthread);
                if (error != 0) {
                        VFS_TO_TMPFS(mp)->tm_ronly = 0;
                        MNT_ILOCK(mp);
                        mp->mnt_flag &= ~MNT_RDONLY;
                        MNT_IUNLOCK(mp);
                        goto out;
                }
                if (!tmpfs_check_rw_maps(mp))
                        break;
        }
out:
        vfs_write_resume(mp, 0);
        return (error);
}

static int
tmpfs_mount(struct mount *mp)
{
        const size_t nodes_per_page = howmany(PAGE_SIZE,
            sizeof(struct tmpfs_dirent) + sizeof(struct tmpfs_node));
        struct tmpfs_mount *tmp;
        struct tmpfs_node *root;
        int error;
        bool nomtime, nonc, pgread;
        /* Size counters. */
        u_quad_t pages;
        off_t nodes_max, size_max, maxfilesize, ea_max_size;

        /* Root node attributes. */
        uid_t root_uid;
        gid_t root_gid;
        mode_t root_mode;

        struct vattr va;

        if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts))
                return (EINVAL);

        if (mp->mnt_flag & MNT_UPDATE) {
                /* Only support update mounts for certain options. */
                if (vfs_filteropt(mp->mnt_optnew, tmpfs_updateopts) != 0)
                        return (EOPNOTSUPP);
                tmp = VFS_TO_TMPFS(mp);
                if (vfs_getopt_size(mp->mnt_optnew, "size", &size_max) == 0) {
                        /*
                         * On-the-fly resizing is not supported (yet). We still
                         * need to have "size" listed as "supported", otherwise
                         * trying to update fs that is listed in fstab with size
                         * parameter, say trying to change rw to ro or vice
                         * versa, would cause vfs_filteropt() to bail.
                         */
                        if (size_max != tmp->tm_size_max)
                                return (EOPNOTSUPP);
                }
                if (vfs_getopt_size(mp->mnt_optnew, "easize", &ea_max_size) == 0) {
                        tmp->tm_ea_memory_max = ea_max_size;
                }
                if (vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0) &&
                    !tmp->tm_ronly) {
                        /* RW -> RO */
                        return (tmpfs_rw_to_ro(mp));
                } else if (!vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0) &&
                    tmp->tm_ronly) {
                        /* RO -> RW */
                        tmp->tm_ronly = 0;
                        MNT_ILOCK(mp);
                        mp->mnt_flag &= ~MNT_RDONLY;
                        MNT_IUNLOCK(mp);
                }
                tmp->tm_nomtime = vfs_getopt(mp->mnt_optnew, "nomtime", NULL,
                    0) == 0;
                MNT_ILOCK(mp);
                if ((mp->mnt_flag & MNT_UNION) == 0) {
                        mp->mnt_kern_flag |= MNTK_FPLOOKUP;
                } else {
                        mp->mnt_kern_flag &= ~MNTK_FPLOOKUP;
                }
                MNT_IUNLOCK(mp);
                return (0);
        }

        vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
        error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred);
        VOP_UNLOCK(mp->mnt_vnodecovered);
        if (error)
                return (error);

        if (mp->mnt_cred->cr_ruid != 0 ||
            vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1)
                root_gid = va.va_gid;
        if (mp->mnt_cred->cr_ruid != 0 ||
            vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1)
                root_uid = va.va_uid;
        if (mp->mnt_cred->cr_ruid != 0 ||
            vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1)
                root_mode = va.va_mode;
        if (vfs_getopt_size(mp->mnt_optnew, "inodes", &nodes_max) != 0)
                nodes_max = 0;
        if (vfs_getopt_size(mp->mnt_optnew, "size", &size_max) != 0)
                size_max = 0;
        if (vfs_getopt_size(mp->mnt_optnew, "maxfilesize", &maxfilesize) != 0)
                maxfilesize = 0;
        if (vfs_getopt_size(mp->mnt_optnew, "easize", &ea_max_size) != 0)
                ea_max_size = 0;
        nonc = vfs_getopt(mp->mnt_optnew, "nonc", NULL, NULL) == 0;
        nomtime = vfs_getopt(mp->mnt_optnew, "nomtime", NULL, NULL) == 0;
        pgread = vfs_getopt(mp->mnt_optnew, "pgread", NULL, NULL) == 0;

        /* Do not allow mounts if we do not have enough memory to preserve
         * the minimum reserved pages. */
        if (tmpfs_mem_avail() < TMPFS_PAGES_MINRESERVED)
                return (ENOSPC);

        /* Get the maximum number of memory pages this file system is
         * allowed to use, based on the maximum size the user passed in
         * the mount structure.  A value of zero is treated as if the
         * maximum available space was requested. */
        if (size_max == 0 || size_max > OFF_MAX - PAGE_SIZE ||
            (SIZE_MAX < OFF_MAX && size_max / PAGE_SIZE >= SIZE_MAX))
                pages = SIZE_MAX;
        else {
                size_max = roundup(size_max, PAGE_SIZE);
                pages = howmany(size_max, PAGE_SIZE);
        }
        MPASS(pages > 0);

        if (nodes_max <= 3) {
                if (pages < INT_MAX / nodes_per_page)
                        nodes_max = pages * nodes_per_page;
                else
                        nodes_max = INT_MAX;
        }
        if (nodes_max > INT_MAX)
                nodes_max = INT_MAX;
        MPASS(nodes_max >= 3);

        /* Allocate the tmpfs mount structure and fill it. */
        tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount),
            M_TMPFSMNT, M_WAITOK | M_ZERO);

        mtx_init(&tmp->tm_allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF);
        tmp->tm_nodes_max = nodes_max;
        tmp->tm_nodes_inuse = 0;
        tmp->tm_ea_memory_inuse = 0;
        tmp->tm_refcount = 1;
        tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : OFF_MAX;
        tmp->tm_ea_memory_max = ea_max_size > 0 ?
            ea_max_size : TMPFS_EA_MEMORY_RESERVED;
        LIST_INIT(&tmp->tm_nodes_used);

        tmp->tm_size_max = size_max;
        tmp->tm_pages_max = pages;
        tmp->tm_pages_used = 0;
        new_unrhdr64(&tmp->tm_ino_unr, 2);
        tmp->tm_ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
        tmp->tm_nonc = nonc;
        tmp->tm_nomtime = nomtime;
        tmp->tm_pgread = pgread;

        /* Allocate the root node. */
        error = tmpfs_alloc_node(mp, tmp, VDIR, root_uid, root_gid,
            root_mode & ALLPERMS, NULL, NULL, VNOVAL, &root);

        if (error != 0 || root == NULL) {
                free(tmp, M_TMPFSMNT);
                return (error);
        }
        KASSERT(root->tn_id == 2,
            ("tmpfs root with invalid ino: %ju", (uintmax_t)root->tn_id));
        tmp->tm_root = root;

        MNT_ILOCK(mp);
        mp->mnt_flag |= MNT_LOCAL;
        mp->mnt_kern_flag |= MNTK_LOOKUP_SHARED | MNTK_EXTENDED_SHARED |
            MNTK_NOMSYNC;
        if (!nonc && (mp->mnt_flag & MNT_UNION) == 0)
                mp->mnt_kern_flag |= MNTK_FPLOOKUP;
        MNT_IUNLOCK(mp);

        mp->mnt_data = tmp;
        mp->mnt_stat.f_namemax = MAXNAMLEN;
        vfs_getnewfsid(mp);
        vfs_mountedfrom(mp, "tmpfs");

        return (0);
}

/* ARGSUSED2 */
static int
tmpfs_unmount(struct mount *mp, int mntflags)
{
        struct tmpfs_mount *tmp;
        struct tmpfs_node *node;
        int error, flags;

        flags = (mntflags & MNT_FORCE) != 0 ? FORCECLOSE : 0;
        tmp = VFS_TO_TMPFS(mp);

        /* Stop writers */
        error = vfs_write_suspend_umnt(mp);
        if (error != 0)
                return (error);
        /*
         * At this point, nodes cannot be destroyed by any other
         * thread because write suspension is started.
         */

        for (;;) {
                error = vflush(mp, 0, flags, curthread);
                if (error != 0) {
                        vfs_write_resume(mp, VR_START_WRITE);
                        return (error);
                }
                MNT_ILOCK(mp);
                if (mp->mnt_nvnodelistsize == 0) {
                        MNT_IUNLOCK(mp);
                        break;
                }
                MNT_IUNLOCK(mp);
                if ((mntflags & MNT_FORCE) == 0) {
                        vfs_write_resume(mp, VR_START_WRITE);
                        return (EBUSY);
                }
        }

        TMPFS_LOCK(tmp);
        while ((node = LIST_FIRST(&tmp->tm_nodes_used)) != NULL) {
                TMPFS_NODE_LOCK(node);
                if (node->tn_type == VDIR)
                        tmpfs_dir_destroy(tmp, node);
                if (tmpfs_free_node_locked(tmp, node, true))
                        TMPFS_LOCK(tmp);
                else
                        TMPFS_NODE_UNLOCK(node);
        }

        mp->mnt_data = NULL;
        tmpfs_free_tmp(tmp);
        vfs_write_resume(mp, VR_START_WRITE);

        return (0);
}

void
tmpfs_free_tmp(struct tmpfs_mount *tmp)
{
        TMPFS_MP_ASSERT_LOCKED(tmp);
        MPASS(tmp->tm_refcount > 0);

        tmp->tm_refcount--;
        if (tmp->tm_refcount > 0) {
                TMPFS_UNLOCK(tmp);
                return;
        }
        TMPFS_UNLOCK(tmp);

        mtx_destroy(&tmp->tm_allnode_lock);
        /*
         * We cannot assert that tmp->tm_pages_used == 0 there,
         * because tmpfs vm_objects might be still mapped by some
         * process and outlive the mount due to reference counting.
         */
        MPASS(tmp->tm_nodes_inuse == 0);

        free(tmp, M_TMPFSMNT);
}

static int
tmpfs_root(struct mount *mp, int flags, struct vnode **vpp)
{
        int error;

        error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp);
        if (error == 0)
                (*vpp)->v_vflag |= VV_ROOT;
        return (error);
}

static int
tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags,
    struct vnode **vpp)
{
        struct tmpfs_fid_data *tfd;
        struct tmpfs_mount *tmp;
        struct tmpfs_node *node;
        int error;

        if (fhp->fid_len != sizeof(*tfd))
                return (EINVAL);

        tfd = (struct tmpfs_fid_data *)fhp;

        tmp = VFS_TO_TMPFS(mp);

        if (tfd->tfd_id >= tmp->tm_nodes_max)
                return (EINVAL);

        TMPFS_LOCK(tmp);
        LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
                if (node->tn_id == tfd->tfd_id &&
                    node->tn_gen == tfd->tfd_gen) {
                        tmpfs_ref_node(node);
                        break;
                }
        }
        TMPFS_UNLOCK(tmp);

        if (node != NULL) {
                error = tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp);
                tmpfs_free_node(tmp, node);
        } else
                error = EINVAL;
        return (error);
}

/* ARGSUSED2 */
static int
tmpfs_statfs(struct mount *mp, struct statfs *sbp)
{
        struct tmpfs_mount *tmp;
        size_t used;

        tmp = VFS_TO_TMPFS(mp);

        sbp->f_iosize = PAGE_SIZE;
        sbp->f_bsize = PAGE_SIZE;

        used = tmpfs_pages_used(tmp);
        if (tmp->tm_pages_max != ULONG_MAX)
                 sbp->f_blocks = tmp->tm_pages_max;
        else
                 sbp->f_blocks = used + tmpfs_mem_avail();
        if (sbp->f_blocks <= used)
                sbp->f_bavail = 0;
        else
                sbp->f_bavail = sbp->f_blocks - used;
        sbp->f_bfree = sbp->f_bavail;
        used = tmp->tm_nodes_inuse;
        sbp->f_files = tmp->tm_nodes_max;
        if (sbp->f_files <= used)
                sbp->f_ffree = 0;
        else
                sbp->f_ffree = sbp->f_files - used;
        /* sbp->f_owner = tmp->tn_uid; */

        return (0);
}

static int
tmpfs_sync(struct mount *mp, int waitfor)
{

        if (waitfor == MNT_SUSPEND) {
                MNT_ILOCK(mp);
                mp->mnt_kern_flag |= MNTK_SUSPEND2 | MNTK_SUSPENDED;
                MNT_IUNLOCK(mp);
        } else if (waitfor == MNT_LAZY) {
                tmpfs_update_mtime_lazy(mp);
        }
        return (0);
}

static int
tmpfs_init(struct vfsconf *conf)
{
        int res;

        res = tmpfs_subr_init();
        if (res != 0)
                return (res);
        memcpy(&tmpfs_fnops, &vnops, sizeof(struct fileops));
        tmpfs_fnops.fo_close = tmpfs_fo_close;
        return (0);
}

static int
tmpfs_uninit(struct vfsconf *conf)
{
        tmpfs_subr_uninit();
        return (0);
}

/*
 * tmpfs vfs operations.
 */
struct vfsops tmpfs_vfsops = {
        .vfs_mount =                    tmpfs_mount,
        .vfs_unmount =                  tmpfs_unmount,
        .vfs_root =                     vfs_cache_root,
        .vfs_cachedroot =               tmpfs_root,
        .vfs_statfs =                   tmpfs_statfs,
        .vfs_fhtovp =                   tmpfs_fhtovp,
        .vfs_sync =                     tmpfs_sync,
        .vfs_init =                     tmpfs_init,
        .vfs_uninit =                   tmpfs_uninit,
};
VFS_SET(tmpfs_vfsops, tmpfs, VFCF_JAIL);

#ifdef DDB
#include <ddb/ddb.h>

static void
db_print_tmpfs(struct mount *mp, struct tmpfs_mount *tmp)
{
        db_printf("mp %p (%s) tmp %p\n", mp,
            mp->mnt_stat.f_mntonname, tmp);
        db_printf(
            "\tsize max %ju pages max %lu pages used %lu\n"
            "\tinodes max %ju inodes inuse %ju ea inuse %ju refcount %ju\n"
            "\tmaxfilesize %ju r%c %snamecache %smtime\n",
            (uintmax_t)tmp->tm_size_max, tmp->tm_pages_max, tmp->tm_pages_used,
            (uintmax_t)tmp->tm_nodes_max, (uintmax_t)tmp->tm_nodes_inuse,
            (uintmax_t)tmp->tm_ea_memory_inuse, (uintmax_t)tmp->tm_refcount,
            (uintmax_t)tmp->tm_maxfilesize,
            tmp->tm_ronly ? 'o' : 'w', tmp->tm_nonc ? "no" : "",
            tmp->tm_nomtime ? "no" : "");
}

DB_SHOW_COMMAND(tmpfs, db_show_tmpfs)
{
        struct mount *mp;
        struct tmpfs_mount *tmp;

        if (have_addr) {
                mp = (struct mount *)addr;
                tmp = VFS_TO_TMPFS(mp);
                db_print_tmpfs(mp, tmp);
                return;
        }

        TAILQ_FOREACH(mp, &mountlist, mnt_list) {
                if (strcmp(mp->mnt_stat.f_fstypename, tmpfs_vfsconf.vfc_name) ==
                    0) {
                        tmp = VFS_TO_TMPFS(mp);
                        db_print_tmpfs(mp, tmp);
                }
        }
}
#endif  /* DDB */