[apple/xnu.git] / bsd / nfs / nfs_vfsops.c

/*
 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * Copyright (c) 1989, 1993, 1995
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Rick Macklem at The University of Guelph.
 *
 * 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.
 *
 *      @(#)nfs_vfsops.c        8.12 (Berkeley) 5/20/95
 * FreeBSD-Id: nfs_vfsops.c,v 1.52 1997/11/12 05:42:21 julian Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/ioctl.h>
#include <sys/signal.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/mount.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>

#include <sys/vm.h>
#include <sys/vmparam.h>

#if !defined(NO_MOUNT_PRIVATE)
#include <sys/filedesc.h>
#endif /* NO_MOUNT_PRIVATE */

#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>

#include <nfs/rpcv2.h>
#include <nfs/nfsproto.h>
#include <nfs/nfs.h>
#include <nfs/nfsnode.h>
#include <nfs/nfsmount.h>
#include <nfs/xdr_subs.h>
#include <nfs/nfsm_subs.h>
#include <nfs/nfsdiskless.h>
#include <nfs/nqnfs.h>

extern int      nfs_mountroot __P((void));

extern int      nfs_ticks;
extern int      nfs_mount_type;
extern int      nfs_resv_mounts;

struct nfsstats nfsstats;
static int nfs_sysctl(int *, u_int, void *, size_t *, void *, size_t,
                      struct proc *);
/* XXX CSM 11/25/97 Upgrade sysctl.h someday */
#ifdef notyet
SYSCTL_NODE(_vfs, MOUNT_NFS, nfs, CTLFLAG_RW, 0, "NFS filesystem");
SYSCTL_STRUCT(_vfs_nfs, NFS_NFSSTATS, nfsstats, CTLFLAG_RD,
        &nfsstats, nfsstats, "");
#endif
#if NFSDIAG
int nfs_debug;
/* XXX CSM 11/25/97 Upgrade sysctl.h someday */
#ifdef notyet
SYSCTL_INT(_vfs_nfs, OID_AUTO, debug, CTLFLAG_RW, &nfs_debug, 0, "");
#endif
#endif

SYSCTL_DECL(_vfs_generic_nfs);
SYSCTL_NODE(_vfs_generic_nfs, OID_AUTO, client, CTLFLAG_RW, 0,
    "nfs client hinge");
/* how long NFS will wait before signalling vfs that it's down. */
static int nfs_tprintf_initial_delay = NFS_TPRINTF_INITIAL_DELAY;
SYSCTL_INT(_vfs_generic_nfs_client, NFS_TPRINTF_INITIAL_DELAY,
    initialdowndelay, CTLFLAG_RW, &nfs_tprintf_initial_delay, 0, "");
/* how long between console messages "nfs server foo not responding" */
static int nfs_tprintf_delay = NFS_TPRINTF_DELAY;
SYSCTL_INT(_vfs_generic_nfs_client, NFS_TPRINTF_DELAY,
    nextdowndelay, CTLFLAG_RW, &nfs_tprintf_delay, 0, "");

static int      nfs_iosize __P((struct nfsmount *nmp));
static int      mountnfs __P((struct nfs_args *,struct mount *,
                        struct mbuf *,char *,char *,struct vnode **));
static int      nfs_mount __P(( struct mount *mp, char *path, caddr_t data,
                        struct nameidata *ndp, struct proc *p));
static int      nfs_start __P(( struct mount *mp, int flags,
                        struct proc *p));
static int      nfs_unmount __P(( struct mount *mp, int mntflags,
                        struct proc *p));
static int      nfs_root __P(( struct mount *mp, struct vnode **vpp));
static int      nfs_quotactl __P(( struct mount *mp, int cmds, uid_t uid,
                        caddr_t arg, struct proc *p));
static int      nfs_statfs __P(( struct mount *mp, struct statfs *sbp,
                        struct proc *p));
static int      nfs_sync __P(( struct mount *mp, int waitfor,
                        struct ucred *cred, struct proc *p));
static int      nfs_vptofh __P(( struct vnode *vp, struct fid *fhp));
static int      nfs_fhtovp __P((struct mount *mp, struct fid *fhp,
                        struct mbuf *nam, struct vnode **vpp,
                        int *exflagsp, struct ucred **credanonp));
static int      nfs_vget __P((struct mount *, void *, struct vnode **));


/*
 * nfs vfs operations.
 */
struct vfsops nfs_vfsops = {
        nfs_mount,
        nfs_start,
        nfs_unmount,
        nfs_root,
        nfs_quotactl,
        nfs_statfs,
        nfs_sync,
        nfs_vget,
        nfs_fhtovp,
        nfs_vptofh,
        nfs_init,
        nfs_sysctl
};
/* XXX CSM 11/25/97 Mysterious kernel.h ld crud */
#ifdef notyet
VFS_SET(nfs_vfsops, nfs, MOUNT_NFS, VFCF_NETWORK);
#endif


void nfsargs_ntoh __P((struct nfs_args *));
static int
nfs_mount_diskless __P((struct nfs_dlmount *, char *, int, struct vnode **,
                                                struct mount **));
#if !defined(NO_MOUNT_PRIVATE)
static int
nfs_mount_diskless_private __P((struct nfs_dlmount *, char *, int,
                                struct vnode **, struct mount **));
#endif /* NO_MOUNT_PRIVATE */
static void nfs_convert_oargs __P((struct nfs_args *args,
                                   struct onfs_args *oargs));
#if NFSDIAG
int nfsreqqusers = 0;
extern int nfsbtlen, nfsbtcpu, nfsbtthread, nfsbt[32];
#endif

static int nfs_iosize(nmp)
        struct nfsmount* nmp;
{
        int iosize;

        /*
         * Calculate the size used for io buffers.  Use the larger
         * of the two sizes to minimise nfs requests but make sure
         * that it is at least one VM page to avoid wasting buffer
         * space and to allow easy mmapping of I/O buffers.
         * The read/write rpc calls handle the splitting up of
         * buffers into multiple requests if the buffer size is
         * larger than the I/O size.
         */
        iosize = max(nmp->nm_rsize, nmp->nm_wsize);
        if (iosize < PAGE_SIZE)
                iosize = PAGE_SIZE;
        return (trunc_page_32(iosize));
}

static void nfs_convert_oargs(args,oargs)
     struct nfs_args *args;
     struct onfs_args *oargs;
{
  args->version = NFS_ARGSVERSION;
  args->addr = oargs->addr;
  args->addrlen = oargs->addrlen;
  args->sotype = oargs->sotype;
  args->proto = oargs->proto;
  args->fh = oargs->fh;
  args->fhsize = oargs->fhsize;
  args->flags = oargs->flags;
  args->wsize = oargs->wsize;
  args->rsize = oargs->rsize;
  args->readdirsize = oargs->readdirsize;
  args->timeo = oargs->timeo;
  args->retrans = oargs->retrans;
  args->maxgrouplist = oargs->maxgrouplist;
  args->readahead = oargs->readahead;
  args->leaseterm = oargs->leaseterm;
  args->deadthresh = oargs->deadthresh;
  args->hostname = oargs->hostname;
}

/*
 * nfs statfs call
 */
int
nfs_statfs(mp, sbp, p)
        struct mount *mp;
        register struct statfs *sbp;
        struct proc *p;
{
        register struct vnode *vp;
        register struct nfs_statfs *sfp;
        register caddr_t cp;
        register u_long *tl;
        register long t1, t2;
        caddr_t bpos, dpos, cp2;
        struct nfsmount *nmp = VFSTONFS(mp);
        int error = 0, v3 = (nmp->nm_flag & NFSMNT_NFSV3), retattr;
        struct mbuf *mreq, *mrep, *md, *mb, *mb2;
        struct ucred *cred;
        extern int nfs_mount_type;
        u_int64_t xid;

#ifndef nolint
        sfp = (struct nfs_statfs *)0;
#endif
        vp = nmp->nm_dvp;
        if (error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p))
                return(error);
        cred = crget();
        cred->cr_ngroups = 1;
        if (v3 && (nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
                (void)nfs_fsinfo(nmp, vp, cred, p);
        nfsstats.rpccnt[NFSPROC_FSSTAT]++;
        nfsm_reqhead(vp, NFSPROC_FSSTAT, NFSX_FH(v3));
        nfsm_fhtom(vp, v3);
        nfsm_request(vp, NFSPROC_FSSTAT, p, cred, &xid);
        if (v3 && mrep)
                nfsm_postop_attr(vp, retattr, &xid);
        nfsm_dissect(sfp, struct nfs_statfs *, NFSX_STATFS(v3));

/* XXX CSM 12/2/97 Cleanup when/if we integrate FreeBSD mount.h */
#ifdef notyet
        sbp->f_type = MOUNT_NFS;
#else
        sbp->f_type = nfs_mount_type;
#endif
        sbp->f_flags = nmp->nm_flag;
        sbp->f_iosize = nfs_iosize(nmp);
        if (v3) {
                /*
                 * Adjust block size to get total block count to fit in a long.
                 * If we can't increase block size enough, clamp to max long.
                 */
                u_quad_t tquad, tquad2, bsize;
                bsize = NFS_FABLKSIZE;

                fxdr_hyper(&sfp->sf_tbytes, &tquad);
                tquad /= bsize;
                while ((tquad & ~0x7fffffff) && (bsize < 0x40000000)) {
                        bsize <<= 1;
                        tquad >>= 1;
                }
                sbp->f_blocks = (tquad & ~0x7fffffff) ? 0x7fffffff : (long)tquad;

                fxdr_hyper(&sfp->sf_fbytes, &tquad);
                tquad /= bsize;
                sbp->f_bfree = (tquad & ~0x7fffffff) ? 0x7fffffff : (long)tquad;

                fxdr_hyper(&sfp->sf_abytes, &tquad);
                tquad /= bsize;
                sbp->f_bavail = (tquad & ~0x7fffffff) ? 0x7fffffff : (long)tquad;

                sbp->f_bsize = (long)bsize;

                /* adjust file slots too... */
                fxdr_hyper(&sfp->sf_tfiles, &tquad);
                fxdr_hyper(&sfp->sf_ffiles, &tquad2);
                while (tquad & ~0x7fffffff) {
                        tquad >>= 1;
                        tquad2 >>= 1;
                }
                sbp->f_files = tquad;
                sbp->f_ffree = tquad2;
        } else {
                sbp->f_bsize = fxdr_unsigned(long, sfp->sf_bsize);
                sbp->f_blocks = fxdr_unsigned(long, sfp->sf_blocks);
                sbp->f_bfree = fxdr_unsigned(long, sfp->sf_bfree);
                sbp->f_bavail = fxdr_unsigned(long, sfp->sf_bavail);
                sbp->f_files = 0;
                sbp->f_ffree = 0;
        }
        if (sbp != &mp->mnt_stat) {
                bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
                bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
        }
        nfsm_reqdone;
        VOP_UNLOCK(vp, 0, p);
        crfree(cred);
        return (error);
}

/*
 * nfs version 3 fsinfo rpc call
 */
int
nfs_fsinfo(nmp, vp, cred, p)
        register struct nfsmount *nmp;
        register struct vnode *vp;
        struct ucred *cred;
        struct proc *p;
{
        register struct nfsv3_fsinfo *fsp;
        register caddr_t cp;
        register long t1, t2;
        register u_long *tl, pref, max;
        caddr_t bpos, dpos, cp2;
        int error = 0, retattr;
        struct mbuf *mreq, *mrep, *md, *mb, *mb2;
        u_int64_t xid;

        nfsstats.rpccnt[NFSPROC_FSINFO]++;
        nfsm_reqhead(vp, NFSPROC_FSINFO, NFSX_FH(1));
        nfsm_fhtom(vp, 1);
        nfsm_request(vp, NFSPROC_FSINFO, p, cred, &xid);
        if (mrep) {
                nfsm_postop_attr(vp, retattr, &xid);
        }
        if (!error) {
                nfsm_dissect(fsp, struct nfsv3_fsinfo *, NFSX_V3FSINFO);
                pref = fxdr_unsigned(u_long, fsp->fs_wtpref);
                if (pref < nmp->nm_wsize)
                        nmp->nm_wsize = (pref + NFS_FABLKSIZE - 1) &
                                ~(NFS_FABLKSIZE - 1);
                max = fxdr_unsigned(u_long, fsp->fs_wtmax);
                if (max < nmp->nm_wsize) {
                        nmp->nm_wsize = max & ~(NFS_FABLKSIZE - 1);
                        if (nmp->nm_wsize == 0)
                                nmp->nm_wsize = max;
                }
                pref = fxdr_unsigned(u_long, fsp->fs_rtpref);
                if (pref < nmp->nm_rsize)
                        nmp->nm_rsize = (pref + NFS_FABLKSIZE - 1) &
                                ~(NFS_FABLKSIZE - 1);
                max = fxdr_unsigned(u_long, fsp->fs_rtmax);
                if (max < nmp->nm_rsize) {
                        nmp->nm_rsize = max & ~(NFS_FABLKSIZE - 1);
                        if (nmp->nm_rsize == 0)
                                nmp->nm_rsize = max;
                }
                pref = fxdr_unsigned(u_long, fsp->fs_dtpref);
                if (pref < nmp->nm_readdirsize)
                        nmp->nm_readdirsize = pref;
                if (max < nmp->nm_readdirsize) {
                        nmp->nm_readdirsize = max;
                }
                nmp->nm_state |= NFSSTA_GOTFSINFO;
        }
        nfsm_reqdone;
        return (error);
}

/*
 * Mount a remote root fs via. nfs. This depends on the info in the
 * nfs_diskless structure that has been filled in properly by some primary
 * bootstrap.
 * It goes something like this:
 * - do enough of "ifconfig" by calling ifioctl() so that the system
 *   can talk to the server
 * - If nfs_diskless.mygateway is filled in, use that address as
 *   a default gateway.
 * - hand craft the swap nfs vnode hanging off a fake mount point
 *      if swdevt[0].sw_dev == NODEV
 * - build the rootfs mount point and call mountnfs() to do the rest.
 */
int
nfs_mountroot()
{
        struct nfs_diskless nd;
        struct vattr attr;
        struct mount *mp;
        struct vnode *vp;
        struct proc *procp;
        long n;
        int error;
#if !defined(NO_MOUNT_PRIVATE)
        struct mount *mppriv;
        struct vnode *vppriv;
#endif /* NO_MOUNT_PRIVATE */
        int v3;

        procp = current_proc(); /* XXX */

        /*
         * Call nfs_boot_init() to fill in the nfs_diskless struct.
         * Note: networking must already have been configured before
         * we're called.
         */
        bzero((caddr_t) &nd, sizeof(nd));
        error = nfs_boot_init(&nd, procp);
        if (error) {
                panic("nfs_boot_init failed with %d\n", error);
        }

        /* try NFSv3 first, if that fails then try NFSv2 */
        v3 = 1;

tryagain:
        error = nfs_boot_getfh(&nd, procp, v3);
        if (error) {
                if (error == EHOSTDOWN || error == EHOSTUNREACH) {
                        if (nd.nd_root.ndm_path)
                                FREE_ZONE(nd.nd_root.ndm_path, 
                                          MAXPATHLEN, M_NAMEI);
                        if (nd.nd_private.ndm_path)
                                FREE_ZONE(nd.nd_private.ndm_path, 
                                          MAXPATHLEN, M_NAMEI);
                        return (error);
                }
                if (v3) {
                        printf("nfs_boot_getfh(v3) failed with %d, trying v2...\n", error);
                        v3 = 0;
                        goto tryagain;
                }
                panic("nfs_boot_getfh(v2) failed with %d\n", error);
        }

        /*
         * Create the root mount point.
         */
#if !defined(NO_MOUNT_PRIVATE)
        if ((error = nfs_mount_diskless(&nd.nd_root, "/", MNT_RDONLY, &vp, &mp))) {
#else
        if (error = nfs_mount_diskless(&nd.nd_root, "/", NULL, &vp, &mp)) {
#endif /* NO_MOUNT_PRIVATE */
                if (v3) {
                        printf("nfs_mount_diskless(v3) failed with %d, trying v2...\n", error);
                        v3 = 0;
                        goto tryagain;
                }
                panic("nfs_mount_diskless root failed with %d\n", error);
        }
        printf("root on %s\n", (char *)&nd.nd_root.ndm_host);

        simple_lock(&mountlist_slock);
        CIRCLEQ_INSERT_TAIL(&mountlist, mp, mnt_list);
        simple_unlock(&mountlist_slock);
        vfs_unbusy(mp, procp);
        rootvp = vp;
        
#if !defined(NO_MOUNT_PRIVATE)
        if (nd.nd_private.ndm_saddr.sin_addr.s_addr) {
            error = nfs_mount_diskless_private(&nd.nd_private, "/private",
                                               NULL, &vppriv, &mppriv);
            if (error) {
                panic("nfs_mount_diskless private failed with %d\n", error);
            }
            printf("private on %s\n", (char *)&nd.nd_private.ndm_host);
            
            simple_lock(&mountlist_slock);
            CIRCLEQ_INSERT_TAIL(&mountlist, mppriv, mnt_list);
            simple_unlock(&mountlist_slock);
            vfs_unbusy(mppriv, procp);
        }

#endif /* NO_MOUNT_PRIVATE */

        if (nd.nd_root.ndm_path)
                FREE_ZONE(nd.nd_root.ndm_path, MAXPATHLEN, M_NAMEI);
        if (nd.nd_private.ndm_path)
                FREE_ZONE(nd.nd_private.ndm_path, MAXPATHLEN, M_NAMEI);

        /* Get root attributes (for the time). */
        error = VOP_GETATTR(vp, &attr, procp->p_ucred, procp);
        if (error) panic("nfs_mountroot: getattr for root");
        n = attr.va_mtime.tv_sec;
        inittodr(n);
        return (0);
}

/*
 * Internal version of mount system call for diskless setup.
 */
static int
nfs_mount_diskless(ndmntp, mntname, mntflag, vpp, mpp)
        struct nfs_dlmount *ndmntp;
        char *mntname;
        int mntflag;
        struct vnode **vpp;
        struct mount **mpp;
{
        struct nfs_args args;
        struct mount *mp;
        struct mbuf *m;
        int error;
        struct proc *procp;

        procp = current_proc(); /* XXX */

        if ((error = vfs_rootmountalloc("nfs", ndmntp->ndm_host, &mp))) {
                printf("nfs_mountroot: NFS not configured");
                return (error);
        }
        mp->mnt_flag = mntflag;

        /* Initialize mount args. */
        bzero((caddr_t) &args, sizeof(args));
        args.addr     = (struct sockaddr *)&ndmntp->ndm_saddr;
        args.addrlen  = args.addr->sa_len;
        args.sotype   = SOCK_DGRAM;
        args.fh       = ndmntp->ndm_fh;
        args.fhsize   = ndmntp->ndm_fhlen;
        args.hostname = ndmntp->ndm_host;
        args.flags    = NFSMNT_RESVPORT;
        if (ndmntp->ndm_nfsv3)
                args.flags |= NFSMNT_NFSV3;

        MGET(m, M_DONTWAIT, MT_SONAME);
        bcopy((caddr_t)args.addr, mtod(m, caddr_t), 
                                (m->m_len = args.addr->sa_len));
        if ((error = mountnfs(&args, mp, m, mntname, args.hostname, vpp))) {
                printf("nfs_mountroot: mount %s failed: %d", mntname, error);
                mp->mnt_vfc->vfc_refcount--;

                if (mp->mnt_kern_flag & MNTK_IO_XINFO)
                        FREE(mp->mnt_xinfo_ptr, M_TEMP);
                vfs_unbusy(mp, procp);

                FREE_ZONE(mp, sizeof (struct mount), M_MOUNT);
                return (error);
        }
#if 0  /* Causes incorrect reporting of "mounted on" */
        (void) copystr(args.hostname, mp->mnt_stat.f_mntonname, MNAMELEN - 1, 0);
#endif /* 0 */
        *mpp = mp;
        return (0);
}

#if !defined(NO_MOUNT_PRIVATE)
/*
 * Internal version of mount system call to mount "/private"
 * separately in diskless setup
 */
static int
nfs_mount_diskless_private(ndmntp, mntname, mntflag, vpp, mpp)
        struct nfs_dlmount *ndmntp;
        char *mntname;
        int mntflag;
        struct vnode **vpp;
        struct mount **mpp;
{
        struct nfs_args args;
        struct mount *mp;
        struct mbuf *m;
        int error;
        struct proc *procp;
        struct vfsconf *vfsp;
        struct nameidata nd;
        struct vnode *vp;

        procp = current_proc(); /* XXX */

        {
        /*
         * mimic main()!. Temporarily set up rootvnode and other stuff so
         * that namei works. Need to undo this because main() does it, too
         */
                struct filedesc *fdp;   /* pointer to file descriptor state */
                fdp = procp->p_fd;
                mountlist.cqh_first->mnt_flag |= MNT_ROOTFS;

                /* Get the vnode for '/'. Set fdp->fd_cdir to reference it. */
                if (VFS_ROOT(mountlist.cqh_first, &rootvnode))
                        panic("cannot find root vnode");
                VREF(rootvnode);
                fdp->fd_cdir = rootvnode;
                VOP_UNLOCK(rootvnode, 0, procp);
                fdp->fd_rdir = NULL;
        }

        /*
         * Get vnode to be covered
         */
        NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
            mntname, procp);
        if ((error = namei(&nd))) {
                printf("nfs_mountroot: private namei failed!");
                return (error);
        }
        {
                /* undo VREF in mimic main()! */
                vrele(rootvnode);
        }
        vp = nd.ni_vp;
        if ((error = vinvalbuf(vp, V_SAVE, procp->p_ucred, procp, 0, 0))) {
                vput(vp);
                return (error);
        }
        if (vp->v_type != VDIR) {
                vput(vp);
                return (ENOTDIR);
        }
        for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
                if (!strcmp(vfsp->vfc_name, "nfs"))
                        break;
        if (vfsp == NULL) {
                printf("nfs_mountroot: private NFS not configured");
                vput(vp);
                return (ENODEV);
        }
        if (vp->v_mountedhere != NULL) {
                vput(vp);
                return (EBUSY);
        }

        /*
         * Allocate and initialize the filesystem.
         */
        mp = _MALLOC_ZONE((u_long)sizeof(struct mount), M_MOUNT, M_WAITOK);
        bzero((char *)mp, (u_long)sizeof(struct mount));

        /* Initialize the default IO constraints */
        mp->mnt_maxreadcnt = mp->mnt_maxwritecnt = MAXPHYS;
        mp->mnt_segreadcnt = mp->mnt_segwritecnt = 32;

        lockinit(&mp->mnt_lock, PVFS, "vfslock", 0, 0);
        (void)vfs_busy(mp, LK_NOWAIT, 0, procp);
        LIST_INIT(&mp->mnt_vnodelist);
        mp->mnt_op = vfsp->vfc_vfsops;
        mp->mnt_vfc = vfsp;
        vfsp->vfc_refcount++;
        mp->mnt_stat.f_type = vfsp->vfc_typenum;
        mp->mnt_flag = mntflag;
        mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
        strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
        vp->v_mountedhere = mp;
        mp->mnt_vnodecovered = vp;
        mp->mnt_stat.f_owner = procp->p_ucred->cr_uid;
        (void) copystr(mntname, mp->mnt_stat.f_mntonname, MNAMELEN - 1, 0);
        (void) copystr(ndmntp->ndm_host, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 0);

        /* Initialize mount args. */
        bzero((caddr_t) &args, sizeof(args));
        args.addr     = (struct sockaddr *)&ndmntp->ndm_saddr;
        args.addrlen  = args.addr->sa_len;
        args.sotype   = SOCK_DGRAM;
        args.fh       = ndmntp->ndm_fh;
        args.fhsize   = ndmntp->ndm_fhlen;
        args.hostname = ndmntp->ndm_host;
        args.flags    = NFSMNT_RESVPORT;
        if (ndmntp->ndm_nfsv3)
                args.flags |= NFSMNT_NFSV3;

        MGET(m, M_DONTWAIT, MT_SONAME);
        bcopy((caddr_t)args.addr, mtod(m, caddr_t), 
                                (m->m_len = args.addr->sa_len));
        if ((error = mountnfs(&args, mp, m, mntname, args.hostname, &vp))) {
                printf("nfs_mountroot: mount %s failed: %d", mntname, error);
                mp->mnt_vfc->vfc_refcount--;

                if (mp->mnt_kern_flag & MNTK_IO_XINFO)
                        FREE(mp->mnt_xinfo_ptr, M_TEMP);
                vfs_unbusy(mp, procp);

                FREE_ZONE(mp, sizeof (struct mount), M_MOUNT);
                return (error);
        }

        *mpp = mp;
        *vpp = vp;
        return (0);
}
#endif /* NO_MOUNT_PRIVATE */

/*
 * VFS Operations.
 *
 * mount system call
 * It seems a bit dumb to copyinstr() the host and path here and then
 * bcopy() them in mountnfs(), but I wanted to detect errors before
 * doing the sockargs() call because sockargs() allocates an mbuf and
 * an error after that means that I have to release the mbuf.
 */
/* ARGSUSED */
static int
nfs_mount(mp, path, data, ndp, p)
        struct mount *mp;
        char *path;
        caddr_t data;
        struct nameidata *ndp;
        struct proc *p;
{
        int error;
        struct nfs_args args;
        struct mbuf *nam;
        struct vnode *vp;
        char pth[MNAMELEN], hst[MNAMELEN];
        size_t len;
        u_char nfh[NFSX_V3FHMAX];

        error = copyin(data, (caddr_t)&args, sizeof (struct nfs_args));
        if (error)
                return (error);
        if (args.version != NFS_ARGSVERSION) {
#ifndef NO_COMPAT_PRELITE2
                /*
                 * If the argument version is unknown, then assume the
                 * caller is a pre-lite2 4.4BSD client and convert its
                 * arguments.
                 */
                struct onfs_args oargs;
                error = copyin(data, (caddr_t)&oargs, sizeof (struct onfs_args));
                if (error)
                        return (error);
                nfs_convert_oargs(&args,&oargs);
#else /* NO_COMPAT_PRELITE2 */
                return (EPROGMISMATCH);
#endif /* !NO_COMPAT_PRELITE2 */
        }
        if (args.fhsize > NFSX_V3FHMAX)
                return (EINVAL);
        error = copyin((caddr_t)args.fh, (caddr_t)nfh, args.fhsize);
        if (error)
                return (error);
        error = copyinstr(path, pth, MNAMELEN-1, &len);
        if (error)
                return (error);
        bzero(&pth[len], MNAMELEN - len);
        error = copyinstr(args.hostname, hst, MNAMELEN-1, &len);
        if (error)
                return (error);
        bzero(&hst[len], MNAMELEN - len);
        /* sockargs() call must be after above copyin() calls */
        error = sockargs(&nam, (caddr_t)args.addr, args.addrlen, MT_SONAME);
        if (error)
                return (error);
        args.fh = nfh;
        error = mountnfs(&args, mp, nam, pth, hst, &vp);
        return (error);
}

/*
 * Common code for mount and mountroot
 */
static int
mountnfs(argp, mp, nam, pth, hst, vpp)
        register struct nfs_args *argp;
        register struct mount *mp;
        struct mbuf *nam;
        char *pth, *hst;
        struct vnode **vpp;
{
        register struct nfsmount *nmp;
        struct nfsnode *np;
        int error, maxio;
        struct vattr attrs;
        struct proc *curproc;

        /*
         * turning off NQNFS until we have further testing
         * with UBC changes, in particular, nfs_pagein and nfs_pageout.
         * Those have NQNFS defined out in conjunction with this
         * returning an error. Remove when fully tested.
         */
        if (argp->flags & NFSMNT_NQNFS) {
                error = NFSERR_NOTSUPP;
                goto bad2;
        }

        /*
         * Silently clear NFSMNT_NOCONN if it's a TCP mount, it makes
         * no sense in that context.
         */
        if (argp->sotype == SOCK_STREAM)
                argp->flags &= ~NFSMNT_NOCONN;
        
        if (mp->mnt_flag & MNT_UPDATE) {
                nmp = VFSTONFS(mp);
                /* update paths, file handles, etc, here        XXX */
                m_freem(nam);
                return (0);
        } else {
                MALLOC_ZONE(nmp, struct nfsmount *,
                                sizeof (struct nfsmount), M_NFSMNT, M_WAITOK);
                bzero((caddr_t)nmp, sizeof (struct nfsmount));
                TAILQ_INIT(&nmp->nm_uidlruhead);
                TAILQ_INIT(&nmp->nm_bufq);
                mp->mnt_data = (qaddr_t)nmp;
        }
        vfs_getnewfsid(mp);
        nmp->nm_mountp = mp;
        nmp->nm_flag = argp->flags;
        if (nmp->nm_flag & NFSMNT_NQNFS)
                /*
                 * We have to set mnt_maxsymlink to a non-zero value so
                 * that COMPAT_43 routines will know that we are setting
                 * the d_type field in directories (and can zero it for
                 * unsuspecting binaries).
                 */
                mp->mnt_maxsymlinklen = 1;
        nmp->nm_timeo = NFS_TIMEO;
        nmp->nm_retry = NFS_RETRANS;
        if (argp->sotype == SOCK_DGRAM) {
                nmp->nm_wsize = NFS_DGRAM_WSIZE;
                nmp->nm_rsize = NFS_DGRAM_RSIZE;
        } else {
                nmp->nm_wsize = NFS_WSIZE;
                nmp->nm_rsize = NFS_RSIZE;
        }
        nmp->nm_readdirsize = NFS_READDIRSIZE;
        nmp->nm_numgrps = NFS_MAXGRPS;
        nmp->nm_readahead = NFS_DEFRAHEAD;
        nmp->nm_leaseterm = NQ_DEFLEASE;
        nmp->nm_deadthresh = NQ_DEADTHRESH;
        nmp->nm_tprintf_delay = nfs_tprintf_delay;
        if (nmp->nm_tprintf_delay < 0)
                nmp->nm_tprintf_delay = 0;
        nmp->nm_tprintf_initial_delay = nfs_tprintf_initial_delay;
        if (nmp->nm_tprintf_initial_delay < 0)
                nmp->nm_tprintf_initial_delay = 0;
        CIRCLEQ_INIT(&nmp->nm_timerhead);
        nmp->nm_inprog = NULLVP;
        bcopy(hst, mp->mnt_stat.f_mntfromname, MNAMELEN);
        bcopy(pth, mp->mnt_stat.f_mntonname, MNAMELEN);
        nmp->nm_nam = nam;

        if ((argp->flags & NFSMNT_TIMEO) && argp->timeo > 0) {
                nmp->nm_timeo = (argp->timeo * NFS_HZ + 5) / 10;
                if (nmp->nm_timeo < NFS_MINTIMEO)
                        nmp->nm_timeo = NFS_MINTIMEO;
                else if (nmp->nm_timeo > NFS_MAXTIMEO)
                        nmp->nm_timeo = NFS_MAXTIMEO;
        }

        if ((argp->flags & NFSMNT_RETRANS) && argp->retrans > 1) {
                nmp->nm_retry = argp->retrans;
                if (nmp->nm_retry > NFS_MAXREXMIT)
                        nmp->nm_retry = NFS_MAXREXMIT;
        }

        if (argp->flags & NFSMNT_NFSV3) {
                if (argp->sotype == SOCK_DGRAM)
                        maxio = NFS_MAXDGRAMDATA;
                else
                        maxio = NFS_MAXDATA;
        } else
                maxio = NFS_V2MAXDATA;

        if ((argp->flags & NFSMNT_WSIZE) && argp->wsize > 0) {
                nmp->nm_wsize = argp->wsize;
                /* Round down to multiple of blocksize */
                nmp->nm_wsize &= ~(NFS_FABLKSIZE - 1);
                if (nmp->nm_wsize <= 0)
                        nmp->nm_wsize = NFS_FABLKSIZE;
        }
        if (nmp->nm_wsize > maxio)
                nmp->nm_wsize = maxio;
        if (nmp->nm_wsize > MAXBSIZE)
                nmp->nm_wsize = MAXBSIZE;

        if ((argp->flags & NFSMNT_RSIZE) && argp->rsize > 0) {
                nmp->nm_rsize = argp->rsize;
                /* Round down to multiple of blocksize */
                nmp->nm_rsize &= ~(NFS_FABLKSIZE - 1);
                if (nmp->nm_rsize <= 0)
                        nmp->nm_rsize = NFS_FABLKSIZE;
        }
        if (nmp->nm_rsize > maxio)
                nmp->nm_rsize = maxio;
        if (nmp->nm_rsize > MAXBSIZE)
                nmp->nm_rsize = MAXBSIZE;

        if ((argp->flags & NFSMNT_READDIRSIZE) && argp->readdirsize > 0) {
                nmp->nm_readdirsize = argp->readdirsize;
        }
        if (nmp->nm_readdirsize > maxio)
                nmp->nm_readdirsize = maxio;
        if (nmp->nm_readdirsize > nmp->nm_rsize)
                nmp->nm_readdirsize = nmp->nm_rsize;

        if ((argp->flags & NFSMNT_MAXGRPS) && argp->maxgrouplist >= 0 &&
                argp->maxgrouplist <= NFS_MAXGRPS)
                nmp->nm_numgrps = argp->maxgrouplist;
        if ((argp->flags & NFSMNT_READAHEAD) && argp->readahead >= 0 &&
                argp->readahead <= NFS_MAXRAHEAD)
                nmp->nm_readahead = argp->readahead;
        if ((argp->flags & NFSMNT_LEASETERM) && argp->leaseterm >= 2 &&
                argp->leaseterm <= NQ_MAXLEASE)
                nmp->nm_leaseterm = argp->leaseterm;
        if ((argp->flags & NFSMNT_DEADTHRESH) && argp->deadthresh >= 1 &&
                argp->deadthresh <= NQ_NEVERDEAD)
                nmp->nm_deadthresh = argp->deadthresh;
        /* Set up the sockets and per-host congestion */
        nmp->nm_sotype = argp->sotype;
        nmp->nm_soproto = argp->proto;

        /*
         * For Connection based sockets (TCP,...) defer the connect until
         * the first request, in case the server is not responding.
         */
        if (nmp->nm_sotype == SOCK_DGRAM &&
                (error = nfs_connect(nmp, (struct nfsreq *)0)))
                goto bad;

        /*
         * A reference count is needed on the nfsnode representing the
         * remote root.  If this object is not persistent, then backward
         * traversals of the mount point (i.e. "..") will not work if
         * the nfsnode gets flushed out of the cache. UFS does not have
         * this problem, because one can identify root inodes by their
         * number == ROOTINO (2).
         */
        error = nfs_nget(mp, (nfsfh_t *)argp->fh, argp->fhsize, &np);
        if (error)
                goto bad;

        /*
         * save this vnode pointer. That way nfs_unmount()
         * does not need to call nfs_net() just get it to drop
         * this vnode reference.
         */
        nmp->nm_dvp = *vpp = NFSTOV(np);

        /*
         * Get file attributes for the mountpoint.  This has the side
         * effect of filling in (*vpp)->v_type with the correct value.
         */
        curproc = current_proc();
        error = VOP_GETATTR(*vpp, &attrs, curproc->p_ucred, curproc);
        if (error) {
                /*
                 * we got problems... we couldn't get the attributes
                 * from the NFS server... so the mount fails.
                 */
                vput(*vpp);
                goto bad;
        }

        /*
         * Set the mount point's block I/O size.
         * We really need to do this after we get info back from
         * the server about what its preferred I/O sizes are.
         */
        if (nmp->nm_flag & NFSMNT_NFSV3)
                nfs_fsinfo(nmp, *vpp, curproc->p_ucred, curproc);
        mp->mnt_stat.f_iosize = nfs_iosize(nmp);

        /*
         * Lose the lock but keep the ref.
         */
        VOP_UNLOCK(*vpp, 0, curproc);

        if (nmp->nm_flag & NFSMNT_RESVPORT)
                nfs_resv_mounts++;
        nmp->nm_state |= NFSSTA_MOUNTED;
        return (0);
bad:
        nfs_disconnect(nmp);
        FREE_ZONE((caddr_t)nmp, sizeof (struct nfsmount), M_NFSMNT);
bad2:
        m_freem(nam);
        return (error);
}


/*
 * unmount system call
 */
static int
nfs_unmount(mp, mntflags, p)
        struct mount *mp;
        int mntflags;
        struct proc *p;
{
        register struct nfsmount *nmp;
        struct vnode *vp;
        int error, flags = 0;

        nmp = VFSTONFS(mp);
        /*
         * During a force unmount we want to...
         *   Mark that we are doing a force unmount.
         *   Make the mountpoint soft.
         */
        if (mntflags & MNT_FORCE) {
                flags |= FORCECLOSE;
                nmp->nm_state |= NFSSTA_FORCE;
                nmp->nm_flag |= NFSMNT_SOFT;
        }
        /*
         * Goes something like this..
         * - Call vflush() to clear out vnodes for this file system,
         *   except for the swap files. Deal with them in 2nd pass.
         *   It will do vgone making the vnode VBAD at that time.
         * - Decrement reference on the vnode representing remote root.
         * - Close the socket
         * - Free up the data structures
         */
        vp = nmp->nm_dvp;
        
        /*
         * Must handshake with nqnfs_clientd() if it is active.
         */
        nmp->nm_state |= NFSSTA_DISMINPROG;
        while (nmp->nm_inprog != NULLVP)
                (void) tsleep((caddr_t)&lbolt, PSOCK, "nfsdism", 0);
        /*
         * vflush will check for busy vnodes on mountpoint. 
         * Will do the right thing for MNT_FORCE. That is, we should
         * not get EBUSY back.
         */
        error = vflush(mp, vp, SKIPSWAP | flags);
        if (mntflags & MNT_FORCE) {
                error = vflush(mp, NULLVP, flags); /* locks vp in the process */
        } else {
                if (vp->v_usecount > 1) {
                        nmp->nm_state &= ~NFSSTA_DISMINPROG;
                        return (EBUSY);
                }
                error = vflush(mp, vp, flags);
        }

        if (error) {
                nmp->nm_state &= ~NFSSTA_DISMINPROG;
                return (error);
        }

        /*
         * We are now committed to the unmount.
         * For NQNFS, let the server daemon free the nfsmount structure.
         */
        if (nmp->nm_flag & (NFSMNT_NQNFS | NFSMNT_KERB))
                nmp->nm_state |= NFSSTA_DISMNT;
        nmp->nm_state &= ~NFSSTA_MOUNTED;
        if (nmp->nm_flag & NFSMNT_RESVPORT) {
                if (--nfs_resv_mounts == 0)
                        nfs_bind_resv_thread_wake();
        }

        /*
         * Release the root vnode reference held by mountnfs()
         * vflush did the vgone for us when we didn't skip over
         * it in the MNT_FORCE case. (Thus vp can't be locked when
         * called vflush in non-skip vp case.)
         */
        vrele(vp);
        if (!(mntflags & MNT_FORCE))
                vgone(vp);
        mp->mnt_data = 0; /* don't want to end up using stale vp */
        nfs_disconnect(nmp);
        m_freem(nmp->nm_nam);

        if ((nmp->nm_flag & (NFSMNT_NQNFS | NFSMNT_KERB)) == 0) {
                register struct nfsreq *rp;
                /*
                 * Loop through outstanding request list and remove dangling
                 * references to defunct nfsmount struct
                 */
#if NFSDIAG && 0
                if (hw_atomic_add(&nfsreqqusers, 1) != 1)
                        nfsatompanic("unmount add");
                nfsbtlen = backtrace(&nfsbt, sizeof(nfsbt));
                nfsbtcpu = cpu_number();
                nfsbtthread = (int)(current_thread());
#endif

                for (rp = nfs_reqq.tqh_first; rp; rp = rp->r_chain.tqe_next)
                        if (rp->r_nmp == nmp)
                                rp->r_nmp = (struct nfsmount *)0;
#if NFSDIAG && 0
                if (hw_atomic_sub(&nfsreqqusers, 1) != 0)
                        nfsatompanic("unmount sub");
#endif
                FREE_ZONE((caddr_t)nmp, sizeof (struct nfsmount), M_NFSMNT);
        }
        return (0);
}

/*
 * Return root of a filesystem
 */
static int
nfs_root(mp, vpp)
        struct mount *mp;
        struct vnode **vpp;
{
        register struct vnode *vp;
        struct nfsmount *nmp;
        int error, vpid;

        nmp = VFSTONFS(mp);
        vp = nmp->nm_dvp;
        vpid = vp->v_id;
        while (error = vget(vp, LK_EXCLUSIVE, current_proc())) {
                /* vget may return ENOENT if the dir changes while in vget */
                /* If that happens, try vget again, else return the error */
                if ((error != ENOENT) || (vp->v_id == vpid))
                        return (error);
                vpid = vp->v_id;
        }
        if (vp->v_type == VNON)
            vp->v_type = VDIR;
        vp->v_flag |= VROOT;
        *vpp = vp;
        return (0);
}

extern int syncprt;

/*
 * Flush out the buffer cache
 */
/* ARGSUSED */
static int
nfs_sync(mp, waitfor, cred, p)
        struct mount *mp;
        int waitfor;
        struct ucred *cred;
        struct proc *p;
{
        register struct vnode *vp;
        int error, allerror = 0;

        /*
         * Force stale buffer cache information to be flushed.
         */
loop:
        LIST_FOREACH(vp, &mp->mnt_vnodelist, v_mntvnodes) {
                 int didhold;
                /*
                 * If the vnode that we are about to sync is no longer
                 * associated with this mount point, start over.
                 */
                if (vp->v_mount != mp)
                        goto loop;
                if (VOP_ISLOCKED(vp) || LIST_FIRST(&VTONFS(vp)->n_dirtyblkhd) == NULL)
                        continue;
                if (vget(vp, LK_EXCLUSIVE, p))
                        goto loop;
                didhold = ubc_hold(vp);
                error = VOP_FSYNC(vp, cred, waitfor, p);
                if (error)
                        allerror = error;
                VOP_UNLOCK(vp, 0, p);
                if (didhold)
                        ubc_rele(vp);
                vrele(vp);
        }
        return (allerror);
}

/*
 * NFS flat namespace lookup.
 * Currently unsupported.
 */
/* ARGSUSED */
static int
nfs_vget(mp, ino, vpp)
        struct mount *mp;
        void *ino; /* XXX void* or ino_t? */
        struct vnode **vpp;
{

        return (EOPNOTSUPP);
}

/*
 * At this point, this should never happen
 */
/* ARGSUSED */
static int
nfs_fhtovp(mp, fhp, nam, vpp, exflagsp, credanonp)
        register struct mount *mp;
        struct fid *fhp;
        struct mbuf *nam;
        struct vnode **vpp;
        int *exflagsp;
        struct ucred **credanonp;
{

        return (EINVAL);
}

/*
 * Vnode pointer to File handle, should never happen either
 */
/* ARGSUSED */
static int
nfs_vptofh(vp, fhp)
        struct vnode *vp;
        struct fid *fhp;
{

        return (EINVAL);
}

/*
 * Vfs start routine, a no-op.
 */
/* ARGSUSED */
static int
nfs_start(mp, flags, p)
        struct mount *mp;
        int flags;
        struct proc *p;
{

        return (0);
}

/*
 * Do operations associated with quotas, not supported
 */
/* ARGSUSED */
static int
nfs_quotactl(mp, cmd, uid, arg, p)
        struct mount *mp;
        int cmd;
        uid_t uid;
        caddr_t arg;
        struct proc *p;
{

        return (EOPNOTSUPP);
}

/*
 * Do that sysctl thang...
 */
static int
nfs_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
           size_t newlen, struct proc *p)
{
        int error = 0, val;
        struct sysctl_req *req;
        struct vfsidctl vc;
        struct mount *mp;
        struct nfsmount *nmp;
        struct vfsquery vq;

        /*
         * All names at this level are terminal.
         */
        if(namelen > 1)
                return ENOTDIR; /* overloaded */

        /* common code for "new style" VFS_CTL sysctl, get the mount. */
        switch (name[0]) {
        case VFS_CTL_TIMEO:
        case VFS_CTL_QUERY:
        case VFS_CTL_NOLOCKS:
                req = oldp;
                error = SYSCTL_IN(req, &vc, sizeof(vc));
                if (error)
                        return (error);
                mp = vfs_getvfs(&vc.vc_fsid);
                if (mp == NULL)
                        return (ENOENT);
                nmp = VFSTONFS(mp);
                if (nmp == NULL)
                        return (ENOENT);
                bzero(&vq, sizeof(vq));
                VCTLTOREQ(&vc, req);
        }

        switch(name[0]) {
        case NFS_NFSSTATS:
                if(!oldp) {
                        *oldlenp = sizeof nfsstats;
                        return 0;
                }

                if(*oldlenp < sizeof nfsstats) {
                        *oldlenp = sizeof nfsstats;
                        return ENOMEM;
                }

                error = copyout(&nfsstats, oldp, sizeof nfsstats);
                if (error)
                        return (error);

                if(newp && newlen != sizeof nfsstats)
                        return EINVAL;

                if(newp) {
                        return copyin(newp, &nfsstats, sizeof nfsstats);
                }
                return 0;
        case VFS_CTL_NOLOCKS:
                val = (nmp->nm_flag & NFSMNT_NOLOCKS) ? 1 : 0;
                if (req->oldptr != NULL) {
                        error = SYSCTL_OUT(req, &val, sizeof(val));
                        if (error)
                                return (error);
                }
                if (req->newptr != NULL) {
                        error = SYSCTL_IN(req, &val, sizeof(val));
                        if (error)
                                return (error);
                        if (val)
                                nmp->nm_flag |= NFSMNT_NOLOCKS;
                        else
                                nmp->nm_flag &= ~NFSMNT_NOLOCKS;
                }
                break;
        case VFS_CTL_QUERY:
                if ((nmp->nm_state & NFSSTA_TIMEO))
                        vq.vq_flags |= VQ_NOTRESP;
                if (!(nmp->nm_flag & NFSMNT_NOLOCKS) &&
                    (nmp->nm_state & NFSSTA_LOCKTIMEO))
                        vq.vq_flags |= VQ_NOTRESPLOCK;
                error = SYSCTL_OUT(req, &vq, sizeof(vq));
                break;
        case VFS_CTL_TIMEO:
                if (req->oldptr != NULL) {
                        error = SYSCTL_OUT(req, &nmp->nm_tprintf_initial_delay,
                            sizeof(nmp->nm_tprintf_initial_delay));
                        if (error)
                                return (error);
                }
                if (req->newptr != NULL) {
                        error = SYSCTL_IN(req, &nmp->nm_tprintf_initial_delay,
                            sizeof(nmp->nm_tprintf_initial_delay));
                        if (error)
                                return (error);
                        if (nmp->nm_tprintf_initial_delay < 0)
                                nmp->nm_tprintf_initial_delay = 0;
                }
                break;
        default:
                return (ENOTSUP);
        }
        return (error);
}