xnu-517.tar.gz

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

/*
 * Copyright (c) 2000-2003 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The 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, QUIET ENJOYMENT 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) 1992, 1993
 *      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_nqlease.c       8.9 (Berkeley) 5/20/95
 * FreeBSD-Id: nfs_nqlease.c,v 1.32 1997/11/07 08:53:23 phk Exp $
 */


/*
 * References:
 *      Cary G. Gray and David R. Cheriton, "Leases: An Efficient Fault-Tolerant
 *              Mechanism for Distributed File Cache Consistency",
 *              In Proc. of the Twelfth ACM Symposium on Operating Systems
 *              Principals, pg. 202-210, Litchfield Park, AZ, Dec. 1989.
 *      Michael N. Nelson, Brent B. Welch and John K. Ousterhout, "Caching
 *              in the Sprite Network File System", ACM TOCS 6(1),
 *              pages 134-154, February 1988.
 *      V. Srinivasan and Jeffrey C. Mogul, "Spritely NFS: Implementation and
 *              Performance of Cache-Consistency Protocols", Digital
 *              Equipment Corporation WRL Research Report 89/5, May 1989.
 */
#include <sys/param.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
#include <machine/spl.h>

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

time_t nqnfsstarttime = (time_t)0;
int nqsrv_clockskew = NQ_CLOCKSKEW;
int nqsrv_writeslack = NQ_WRITESLACK;
int nqsrv_maxlease = NQ_MAXLEASE;
static int nqsrv_maxnumlease = NQ_MAXNUMLEASE;

struct vop_lease_args;

static int      nqsrv_cmpnam __P((struct nfssvc_sock *, struct mbuf *,
                        struct nqhost *));
extern void     nqnfs_lease_updatetime __P((int deltat));
static int      nqnfs_vacated __P((struct vnode *vp, struct ucred *cred));
static void     nqsrv_addhost __P((struct nqhost *lph, struct nfssvc_sock *slp,
                                   struct mbuf *nam));
static void     nqsrv_instimeq __P((struct nqlease *lp, u_long duration));
static void     nqsrv_locklease __P((struct nqlease *lp));
static void     nqsrv_send_eviction __P((struct vnode *vp, struct nqlease *lp,
                                         struct nfssvc_sock *slp,
                                         struct mbuf *nam, struct ucred *cred));
static void     nqsrv_unlocklease __P((struct nqlease *lp));
static void     nqsrv_waitfor_expiry __P((struct nqlease *lp));

/*
 * Signifies which rpcs can have piggybacked lease requests
 */
int nqnfs_piggy[NFS_NPROCS] = {
        0,
        0,
        ND_WRITE,
        ND_READ,
        0,
        ND_READ,
        ND_READ,
        ND_WRITE,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        ND_READ,
        ND_READ,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
};

extern nfstype nfsv2_type[9];
extern nfstype nfsv3_type[9];
extern struct nfssvc_sock *nfs_udpsock, *nfs_cltpsock;
extern int nfsd_waiting;
extern struct nfsstats nfsstats;
extern int nfs_mount_type;

#define TRUE    1
#define FALSE   0

#ifndef NFS_NOSERVER 
/*
 * Get or check for a lease for "vp", based on ND_CHECK flag.
 * The rules are as follows:
 * - if a current non-caching lease, reply non-caching
 * - if a current lease for same host only, extend lease
 * - if a read cachable lease and a read lease request
 *      add host to list any reply cachable
 * - else { set non-cachable for read-write sharing }
 *      send eviction notice messages to all other hosts that have lease
 *      wait for lease termination { either by receiving vacated messages
 *                                      from all the other hosts or expiry
 *                                      via. timeout }
 *      modify lease to non-cachable
 * - else if no current lease, issue new one
 * - reply
 * - return boolean TRUE iff nam should be m_freem()'d
 * NB: Since nqnfs_serverd() is called from a timer, any potential tsleep()
 *     in here must be framed by nqsrv_locklease() and nqsrv_unlocklease().
 *     nqsrv_locklease() is coded such that at least one of LC_LOCKED and
 *     LC_WANTED is set whenever a process is tsleeping in it. The exception
 *     is when a new lease is being allocated, since it is not in the timer
 *     queue yet. (Ditto for the splsoftclock() and splx(s) calls)
 */
int
nqsrv_getlease(vp, duration, flags, slp, procp, nam, cachablep, frev, cred)
        struct vnode *vp;
        u_long *duration;
        int flags;
        struct nfssvc_sock *slp;
        struct proc *procp;
        struct mbuf *nam;
        int *cachablep;
        u_quad_t *frev;
        struct ucred *cred;
{
        register struct nqlease *lp;
        register struct nqfhhashhead *lpp = 0;
        register struct nqhost *lph = 0;
        struct nqlease *tlp;
        struct nqm **lphp;
        struct vattr vattr;
        fhandle_t fh;
        int i, ok, error, s;

        if (vp->v_type != VREG && vp->v_type != VDIR && vp->v_type != VLNK)
                return (0);
        if (*duration > nqsrv_maxlease)
                *duration = nqsrv_maxlease;
        error = VOP_GETATTR(vp, &vattr, cred, procp);
        if (error)
                return (error);
        *frev = vattr.va_filerev;
        s = splsoftclock();
        tlp = vp->v_lease;
        if ((flags & ND_CHECK) == 0)
                nfsstats.srvnqnfs_getleases++;
        if (tlp == (struct nqlease *)0) {

                /*
                 * Find the lease by searching the hash list.
                 */
                fh.fh_fsid = vp->v_mount->mnt_stat.f_fsid;
                error = VFS_VPTOFH(vp, &fh.fh_fid);
                if (error) {
                        splx(s);
                        return (error);
                }
                lpp = NQFHHASH(fh.fh_fid.fid_data);
                for (lp = lpp->lh_first; lp != 0; lp = lp->lc_hash.le_next)
                        if (fh.fh_fsid.val[0] == lp->lc_fsid.val[0] &&
                            fh.fh_fsid.val[1] == lp->lc_fsid.val[1] &&
                            !bcmp(fh.fh_fid.fid_data, lp->lc_fiddata,
                                  fh.fh_fid.fid_len - sizeof (long))) {
                                /* Found it */
                                lp->lc_vp = vp;
                                vp->v_lease = lp;
                                tlp = lp;
                                break;
                        }
        } else
                lp = tlp;
        if (lp) {
                if ((lp->lc_flag & LC_NONCACHABLE) ||
                    (lp->lc_morehosts == (struct nqm *)0 &&
                     nqsrv_cmpnam(slp, nam, &lp->lc_host)))
                        goto doreply;
                if ((flags & ND_READ) && (lp->lc_flag & LC_WRITE) == 0) {
                        if (flags & ND_CHECK)
                                goto doreply;
                        if (nqsrv_cmpnam(slp, nam, &lp->lc_host))
                                goto doreply;
                        i = 0;
                        if (lp->lc_morehosts) {
                                lph = lp->lc_morehosts->lpm_hosts;
                                lphp = &lp->lc_morehosts->lpm_next;
                                ok = 1;
                        } else {
                                lphp = &lp->lc_morehosts;
                                ok = 0;
                        }
                        while (ok && (lph->lph_flag & LC_VALID)) {
                                if (nqsrv_cmpnam(slp, nam, lph))
                                        goto doreply;
                                if (++i == LC_MOREHOSTSIZ) {
                                        i = 0;
                                        if (*lphp) {
                                                lph = (*lphp)->lpm_hosts;
                                                lphp = &((*lphp)->lpm_next);
                                        } else
                                                ok = 0;
                                } else
                                        lph++;
                        }
                        nqsrv_locklease(lp);
                        if (!ok) {
                                MALLOC_ZONE(*lphp, struct nqm *,
                                                sizeof(struct nqm),
                                                        M_NQMHOST, M_WAITOK);
                                bzero((caddr_t)*lphp, sizeof (struct nqm));
                                lph = (*lphp)->lpm_hosts;
                        }
                        nqsrv_addhost(lph, slp, nam);
                        nqsrv_unlocklease(lp);
                } else {
                        lp->lc_flag |= LC_NONCACHABLE;
                        nqsrv_locklease(lp);
                        nqsrv_send_eviction(vp, lp, slp, nam, cred);
                        nqsrv_waitfor_expiry(lp);
                        nqsrv_unlocklease(lp);
                }
doreply:
                /*
                 * Update the lease and return
                 */
                if ((flags & ND_CHECK) == 0)
                        nqsrv_instimeq(lp, *duration);
                if (lp->lc_flag & LC_NONCACHABLE)
                        *cachablep = 0;
                else {
                        *cachablep = 1;
                        if (flags & ND_WRITE)
                                lp->lc_flag |= LC_WRITTEN;
                }
                splx(s);
                return (0);
        }
        splx(s);
        if (flags & ND_CHECK)
                return (0);

        /*
         * Allocate new lease
         * The value of nqsrv_maxnumlease should be set generously, so that
         * the following "printf" happens infrequently.
         */
        if (nfsstats.srvnqnfs_leases > nqsrv_maxnumlease) {
                printf("Nqnfs server, too many leases\n");
                do {
                        (void) tsleep((caddr_t)&lbolt, PSOCK,
                                        "nqsrvnuml", 0);
                } while (nfsstats.srvnqnfs_leases > nqsrv_maxnumlease);
        }
        MALLOC_ZONE(lp, struct nqlease *,
                        sizeof (struct nqlease), M_NQLEASE, M_WAITOK);
        bzero((caddr_t)lp, sizeof (struct nqlease));
        if (flags & ND_WRITE)
                lp->lc_flag |= (LC_WRITE | LC_WRITTEN);
        nqsrv_addhost(&lp->lc_host, slp, nam);
        lp->lc_vp = vp;
        lp->lc_fsid = fh.fh_fsid;
        bcopy(fh.fh_fid.fid_data, lp->lc_fiddata,
                fh.fh_fid.fid_len - sizeof (long));
        if(!lpp)
                panic("nfs_nqlease.c: Phoney lpp");
        LIST_INSERT_HEAD(lpp, lp, lc_hash);
        vp->v_lease = lp;
        s = splsoftclock();
        nqsrv_instimeq(lp, *duration);
        splx(s);
        *cachablep = 1;
        if (++nfsstats.srvnqnfs_leases > nfsstats.srvnqnfs_maxleases)
                nfsstats.srvnqnfs_maxleases = nfsstats.srvnqnfs_leases;
        return (0);
}

/*
 * Local lease check for server syscalls.
 * Just set up args and let nqsrv_getlease() do the rest.
 * nqnfs_vop_lease_check() is the VOP_LEASE() form of the same routine.
 * Ifdef'd code in nfsnode.h renames these routines to whatever a particular
 * OS needs.
 */
void
nqnfs_lease_check(vp, p, cred, flag)
        struct vnode *vp;
        struct proc *p;
        struct ucred *cred;
        int flag;
{
        u_long duration = 0;
        int cache;
        u_quad_t frev;

        (void) nqsrv_getlease(vp, &duration, ND_CHECK | flag, NQLOCALSLP,
                p, (struct mbuf *)0, &cache, &frev, cred);
}

int
nqnfs_vop_lease_check(ap)
        struct vop_lease_args /* {
                struct vnode *a_vp;
                struct proc *a_p;
                struct ucred *a_cred;
                int a_flag;
        } */ *ap;
{
        u_long duration = 0;
        int cache;
        u_quad_t frev;

        (void) nqsrv_getlease(ap->a_vp, &duration, ND_CHECK | ap->a_flag,
            NQLOCALSLP, ap->a_p, (struct mbuf *)0, &cache, &frev, ap->a_cred);
        return (0);
}

#endif /* NFS_NOSERVER */

/*
 * Add a host to an nqhost structure for a lease.
 */
static void
nqsrv_addhost(lph, slp, nam)
        register struct nqhost *lph;
        struct nfssvc_sock *slp;
        struct mbuf *nam;
{
        register struct sockaddr_in *saddr;

        if (slp == NQLOCALSLP)
                lph->lph_flag |= (LC_VALID | LC_LOCAL);
        else if (slp == nfs_udpsock) {
                saddr = mtod(nam, struct sockaddr_in *);
                lph->lph_flag |= (LC_VALID | LC_UDP);
                lph->lph_inetaddr = saddr->sin_addr.s_addr;
                lph->lph_port = saddr->sin_port;
        } else if (slp == nfs_cltpsock) {
                lph->lph_nam = m_copym(nam, 0, M_COPYALL, M_WAIT);
                lph->lph_flag |= (LC_VALID | LC_CLTP);
        } else {
                lph->lph_flag |= (LC_VALID | LC_SREF);
                lph->lph_slp = slp;
                slp->ns_sref++;
        }
}

/*
 * Update the lease expiry time and position it in the timer queue correctly.
 */
static void
nqsrv_instimeq(lp, duration)
        register struct nqlease *lp;
        u_long duration;
{
        register struct nqlease *tlp;
        time_t newexpiry;
        struct timeval now;

        microtime(&now);
        newexpiry = now.tv_sec + duration + nqsrv_clockskew;
        if (lp->lc_expiry == newexpiry)
                return;
        if (lp->lc_timer.cqe_next != 0) {
                CIRCLEQ_REMOVE(&nqtimerhead, lp, lc_timer);
        }
        lp->lc_expiry = newexpiry;

        /*
         * Find where in the queue it should be.
         */
        tlp = nqtimerhead.cqh_last;
        while (tlp != (void *)&nqtimerhead && tlp->lc_expiry > newexpiry)
                tlp = tlp->lc_timer.cqe_prev;
#ifdef HASNVRAM
        if (tlp == nqtimerhead.cqh_last)
                NQSTORENOVRAM(newexpiry);
#endif /* HASNVRAM */
        if (tlp == (void *)&nqtimerhead) {
                CIRCLEQ_INSERT_HEAD(&nqtimerhead, lp, lc_timer);
        } else {
                CIRCLEQ_INSERT_AFTER(&nqtimerhead, tlp, lp, lc_timer);
        }
}

/*
 * Compare the requesting host address with the lph entry in the lease.
 * Return true iff it is the same.
 * This is somewhat messy due to the union in the nqhost structure.
 * The local host is indicated by the special value of NQLOCALSLP for slp.
 */
static int
nqsrv_cmpnam(slp, nam, lph)
        register struct nfssvc_sock *slp;
        struct mbuf *nam;
        register struct nqhost *lph;
{
        register struct sockaddr_in *saddr;
        struct mbuf *addr;
        union nethostaddr lhaddr;
        int ret;

        if (slp == NQLOCALSLP) {
                if (lph->lph_flag & LC_LOCAL)
                        return (1);
                else
                        return (0);
        }
        if (slp == nfs_udpsock || slp == nfs_cltpsock)
                addr = nam;
        else
                addr = slp->ns_nam;
        if (lph->lph_flag & LC_UDP)
                ret = netaddr_match(AF_INET, &lph->lph_haddr, addr);
        else if (lph->lph_flag & LC_CLTP)
                ret = netaddr_match(AF_ISO, &lph->lph_claddr, addr);
        else {
                if ((lph->lph_slp->ns_flag & SLP_VALID) == 0)
                        return (0);
                saddr = mtod(lph->lph_slp->ns_nam, struct sockaddr_in *);
                if (saddr->sin_family == AF_INET)
                        lhaddr.had_inetaddr = saddr->sin_addr.s_addr;
                else
                        lhaddr.had_nam = lph->lph_slp->ns_nam;
                ret = netaddr_match(saddr->sin_family, &lhaddr, addr);
        }
        return (ret);
}

/*
 * Send out eviction notice messages to all other hosts for the lease.
 */
static void
nqsrv_send_eviction(vp, lp, slp, nam, cred)
        struct vnode *vp;
        register struct nqlease *lp;
        struct nfssvc_sock *slp;
        struct mbuf *nam;
        struct ucred *cred;
{
        register struct nqhost *lph = &lp->lc_host;
        register struct mbuf *m;
        register int siz;
        struct nqm *lphnext = lp->lc_morehosts;
        struct mbuf *mreq, *mb, *mb2, *mheadend;
        struct socket *so;
        struct mbuf *nam2;
        struct sockaddr_in *saddr;
        nfsfh_t nfh;
        fhandle_t *fhp;
        caddr_t bpos, cp;
        u_long xid, *tl;
        int len = 1, ok = 1, i = 0;
        int sotype, solock;

        while (ok && (lph->lph_flag & LC_VALID)) {
                if (nqsrv_cmpnam(slp, nam, lph))
                        lph->lph_flag |= LC_VACATED;
                else if ((lph->lph_flag & (LC_LOCAL | LC_VACATED)) == 0) {
                        if (lph->lph_flag & LC_UDP) {
                                MGET(nam2, M_WAIT, MT_SONAME);
                                saddr = mtod(nam2, struct sockaddr_in *);
                                nam2->m_len = saddr->sin_len =
                                        sizeof (struct sockaddr_in);
                                saddr->sin_family = AF_INET;
                                saddr->sin_addr.s_addr = lph->lph_inetaddr;
                                saddr->sin_port = lph->lph_port;
                                so = nfs_udpsock->ns_so;
                        } else if (lph->lph_flag & LC_CLTP) {
                                nam2 = lph->lph_nam;
                                so = nfs_cltpsock->ns_so;
                        } else if (lph->lph_slp->ns_flag & SLP_VALID) {
                                nam2 = (struct mbuf *)0;
                                so = lph->lph_slp->ns_so;
                        } else
                                goto nextone;
                        sotype = so->so_type;
                        solock = (so->so_proto->pr_flags & PR_CONNREQUIRED);
                        nfsm_reqhead((struct vnode *)0, NQNFSPROC_EVICTED,
                                NFSX_V3FH + NFSX_UNSIGNED);
                        fhp = &nfh.fh_generic;
                        bzero((caddr_t)fhp, sizeof(nfh));
                        fhp->fh_fsid = vp->v_mount->mnt_stat.f_fsid;
                        VFS_VPTOFH(vp, &fhp->fh_fid);
                        nfsm_srvfhtom(fhp, 1);
                        m = mreq;
                        siz = 0;
                        while (m) {
                                siz += m->m_len;
                                m = m->m_next;
                        }
                        if (siz <= 0 || siz > NFS_MAXPACKET) {
                                printf("mbuf siz=%d\n",siz);
                                panic("Bad nfs svc reply");
                        }
                        m = nfsm_rpchead(cred, (NFSMNT_NFSV3 | NFSMNT_NQNFS),
                                NQNFSPROC_EVICTED,
                                RPCAUTH_UNIX, 5 * NFSX_UNSIGNED, (char *)0,
                                0, (char *)NULL, mreq, siz, &mheadend, &xid);
                        /*
                         * For stream protocols, prepend a Sun RPC
                         * Record Mark.
                         */
                        if (sotype == SOCK_STREAM) {
                                M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
                                *mtod(m, u_long *) = htonl(0x80000000 |
                                        (m->m_pkthdr.len - NFSX_UNSIGNED));
                        }
                        if (((lph->lph_flag & (LC_UDP | LC_CLTP)) == 0 &&
                            (lph->lph_slp->ns_flag & SLP_VALID) == 0) ||
                            (solock && nfs_slplock(lph->lph_slp, 0) == 0)) {
                                m_freem(m);
                        } else {
                                (void) nfs_send(so, nam2, m,
                                                (struct nfsreq *)0);
                                if (solock)
                                        nfs_slpunlock(lph->lph_slp);
                        }
                        if (lph->lph_flag & LC_UDP)
                                MFREE(nam2, m);
                }
nextone:
                if (++i == len) {
                        if (lphnext) {
                                i = 0;
                                len = LC_MOREHOSTSIZ;
                                lph = lphnext->lpm_hosts;
                                lphnext = lphnext->lpm_next;
                        } else
                                ok = 0;
                } else
                        lph++;
        }
}

/*
 * Wait for the lease to expire.
 * This will occur when all clients have sent "vacated" messages to
 * this server OR when it expires do to timeout.
 */
static void
nqsrv_waitfor_expiry(lp)
        register struct nqlease *lp;
{
        register struct nqhost *lph;
        register int i;
        struct nqm *lphnext;
        int len, ok;
        struct timeval now;

tryagain:
        microtime(&now);
        if (now.tv_sec > lp->lc_expiry)
                return;
        lph = &lp->lc_host;
        lphnext = lp->lc_morehosts;
        len = 1;
        i = 0;
        ok = 1;
        while (ok && (lph->lph_flag & LC_VALID)) {
                if ((lph->lph_flag & (LC_LOCAL | LC_VACATED)) == 0) {
                        lp->lc_flag |= LC_EXPIREDWANTED;
                        (void) tsleep((caddr_t)&lp->lc_flag, PSOCK,
                                        "nqexp", 0);
                        goto tryagain;
                }
                if (++i == len) {
                        if (lphnext) {
                                i = 0;
                                len = LC_MOREHOSTSIZ;
                                lph = lphnext->lpm_hosts;
                                lphnext = lphnext->lpm_next;
                        } else
                                ok = 0;
                } else
                        lph++;
        }
}

#ifndef NFS_NOSERVER

/*
 * Nqnfs server timer that maintains the server lease queue.
 * Scan the lease queue for expired entries:
 * - when one is found, wakeup anyone waiting for it
 *   else dequeue and free
 */
void
nqnfs_serverd()
{
        register struct nqlease *lp;
        register struct nqhost *lph;
        struct nqlease *nextlp;
        struct nqm *lphnext, *olphnext;
        struct mbuf *n;
        int i, len, ok;
        struct timeval now;

        microtime(&now);
        for (lp = nqtimerhead.cqh_first; lp != (void *)&nqtimerhead;
            lp = nextlp) {
                if (lp->lc_expiry >= now.tv_sec)
                        break;
                nextlp = lp->lc_timer.cqe_next;
                if (lp->lc_flag & LC_EXPIREDWANTED) {
                        lp->lc_flag &= ~LC_EXPIREDWANTED;
                        wakeup((caddr_t)&lp->lc_flag);
                } else if ((lp->lc_flag & (LC_LOCKED | LC_WANTED)) == 0) {
                    /*
                     * Make a best effort at keeping a write caching lease long
                     * enough by not deleting it until it has been explicitly
                     * vacated or there have been no writes in the previous
                     * write_slack seconds since expiry and the nfsds are not
                     * all busy. The assumption is that if the nfsds are not
                     * all busy now (no queue of nfs requests), then the client
                     * would have been able to do at least one write to the
                     * file during the last write_slack seconds if it was still
                     * trying to push writes to the server.
                     */
                    if ((lp->lc_flag & (LC_WRITE | LC_VACATED)) == LC_WRITE &&
                        ((lp->lc_flag & LC_WRITTEN) || nfsd_waiting == 0)) {
                        lp->lc_flag &= ~LC_WRITTEN;
                        nqsrv_instimeq(lp, nqsrv_writeslack);
                    } else {
                        CIRCLEQ_REMOVE(&nqtimerhead, lp, lc_timer);
                        LIST_REMOVE(lp, lc_hash);
                        /*
                         * This soft reference may no longer be valid, but
                         * no harm done. The worst case is if the vnode was
                         * recycled and has another valid lease reference,
                         * which is dereferenced prematurely.
                         */
                        lp->lc_vp->v_lease = (struct nqlease *)0;
                        lph = &lp->lc_host;
                        lphnext = lp->lc_morehosts;
                        olphnext = (struct nqm *)0;
                        len = 1;
                        i = 0;
                        ok = 1;
                        while (ok && (lph->lph_flag & LC_VALID)) {
                                if (lph->lph_flag & LC_CLTP)
                                        MFREE(lph->lph_nam, n);
                                if (lph->lph_flag & LC_SREF)
                                        nfsrv_slpderef(lph->lph_slp);
                                if (++i == len) {
                                        if (olphnext) {
                                                FREE_ZONE((caddr_t)olphnext,
                                                        sizeof (struct nqm),
                                                                M_NQMHOST);
                                                olphnext = (struct nqm *)0;
                                        }
                                        if (lphnext) {
                                                olphnext = lphnext;
                                                i = 0;
                                                len = LC_MOREHOSTSIZ;
                                                lph = lphnext->lpm_hosts;
                                                lphnext = lphnext->lpm_next;
                                        } else
                                                ok = 0;
                                } else
                                        lph++;
                        }
                        FREE_ZONE((caddr_t)lp,
                                        sizeof (struct nqlease), M_NQLEASE);
                        if (olphnext)
                                FREE_ZONE((caddr_t)olphnext,
                                        sizeof (struct nqm), M_NQMHOST);
                        nfsstats.srvnqnfs_leases--;
                    }
                }
        }
}

/*
 * Called from nfssvc_nfsd() for a getlease rpc request.
 * Do the from/to xdr translation and call nqsrv_getlease() to
 * do the real work.
 */
int
nqnfsrv_getlease(nfsd, slp, procp, mrq)
        struct nfsrv_descript *nfsd;
        struct nfssvc_sock *slp;
        struct proc *procp;
        struct mbuf **mrq;
{
        struct mbuf *mrep = nfsd->nd_mrep, *md = nfsd->nd_md;
        struct mbuf *nam = nfsd->nd_nam;
        caddr_t dpos = nfsd->nd_dpos;
        struct ucred *cred = &nfsd->nd_cr;
        register struct nfs_fattr *fp;
        struct vattr va;
        register struct vattr *vap = &va;
        struct vnode *vp;
        nfsfh_t nfh;
        fhandle_t *fhp;
        register u_long *tl;
        register long t1;
        u_quad_t frev;
        caddr_t bpos;
        int error = 0;
        char *cp2;
        struct mbuf *mb, *mb2, *mreq;
        int flags, rdonly, cache;

        fhp = &nfh.fh_generic;
        nfsm_srvmtofh(fhp);
        nfsm_dissect(tl, u_long *, 2 * NFSX_UNSIGNED);
        flags = fxdr_unsigned(int, *tl++);
        nfsd->nd_duration = fxdr_unsigned(int, *tl);
        error = nfsrv_fhtovp(fhp, 1, &vp, cred, slp, nam, &rdonly,
                (nfsd->nd_flag & ND_KERBAUTH), TRUE);
        if (error)
                nfsm_reply(0);
        if (rdonly && flags == ND_WRITE) {
                error = EROFS;
                vput(vp);
                nfsm_reply(0);
        }
        (void) nqsrv_getlease(vp, &nfsd->nd_duration, flags, slp, procp,
                nam, &cache, &frev, cred);
        error = VOP_GETATTR(vp, vap, cred, procp);
        vput(vp);
        nfsm_reply(NFSX_V3FATTR + 4 * NFSX_UNSIGNED);
        nfsm_build(tl, u_long *, 4 * NFSX_UNSIGNED);
        *tl++ = txdr_unsigned(cache);
        *tl++ = txdr_unsigned(nfsd->nd_duration);
        txdr_hyper(&frev, tl);
        nfsm_build(fp, struct nfs_fattr *, NFSX_V3FATTR);
        nfsm_srvfillattr(vap, fp);
        nfsm_srvdone;
}

/*
 * Called from nfssvc_nfsd() when a "vacated" message is received from a
 * client. Find the entry and expire it.
 */
int
nqnfsrv_vacated(nfsd, slp, procp, mrq)
        struct nfsrv_descript *nfsd;
        struct nfssvc_sock *slp;
        struct proc *procp;
        struct mbuf **mrq;
{
        struct mbuf *mrep = nfsd->nd_mrep, *md = nfsd->nd_md;
        struct mbuf *nam = nfsd->nd_nam;
        caddr_t dpos = nfsd->nd_dpos;
        register struct nqlease *lp;
        register struct nqhost *lph;
        struct nqlease *tlp = (struct nqlease *)0;
        nfsfh_t nfh;
        fhandle_t *fhp;
        register u_long *tl;
        register long t1;
        struct nqm *lphnext;
        struct mbuf *mreq, *mb;
        int error = 0, i, len, ok, gotit = 0, cache = 0;
        char *cp2, *bpos;
        u_quad_t frev;

        fhp = &nfh.fh_generic;
        nfsm_srvmtofh(fhp);
        m_freem(mrep);
        /*
         * Find the lease by searching the hash list.
         */
        for (lp = NQFHHASH(fhp->fh_fid.fid_data)->lh_first; lp != 0;
            lp = lp->lc_hash.le_next)
                if (fhp->fh_fsid.val[0] == lp->lc_fsid.val[0] &&
                    fhp->fh_fsid.val[1] == lp->lc_fsid.val[1] &&
                    !bcmp(fhp->fh_fid.fid_data, lp->lc_fiddata,
                          MAXFIDSZ)) {
                        /* Found it */
                        tlp = lp;
                        break;
                }
        if (tlp) {
                lp = tlp;
                len = 1;
                i = 0;
                lph = &lp->lc_host;
                lphnext = lp->lc_morehosts;
                ok = 1;
                while (ok && (lph->lph_flag & LC_VALID)) {
                        if (nqsrv_cmpnam(slp, nam, lph)) {
                                lph->lph_flag |= LC_VACATED;
                                gotit++;
                                break;
                        }
                        if (++i == len) {
                                if (lphnext) {
                                        len = LC_MOREHOSTSIZ;
                                        i = 0;
                                        lph = lphnext->lpm_hosts;
                                        lphnext = lphnext->lpm_next;
                                } else
                                        ok = 0;
                        } else
                                lph++;
                }
                if ((lp->lc_flag & LC_EXPIREDWANTED) && gotit) {
                        lp->lc_flag &= ~LC_EXPIREDWANTED;
                        wakeup((caddr_t)&lp->lc_flag);
                }
nfsmout:
                return (EPERM);
        }
        return (EPERM);
}

#endif /* NFS_NOSERVER */

/*
 * Client get lease rpc function.
 */
int
nqnfs_getlease(vp, rwflag, cred, p)
        register struct vnode *vp;
        int rwflag;
        struct ucred *cred;
        struct proc *p;
{
        register u_long *tl;
        register caddr_t cp;
        register long t1, t2;
        register struct nfsnode *np;
        struct nfsmount *nmp;
        caddr_t bpos, dpos, cp2;
        struct timeval now;
        time_t reqtime;
        int error = 0;
        struct mbuf *mreq, *mrep, *md, *mb, *mb2;
        int cachable;
        u_quad_t frev;
        u_int64_t xid;

        nmp = VFSTONFS(vp->v_mount);
        if (!nmp)
                return (ENXIO);

        nfsstats.rpccnt[NQNFSPROC_GETLEASE]++;
        mb = mreq = nfsm_reqh(vp, NQNFSPROC_GETLEASE, NFSX_V3FH+2*NFSX_UNSIGNED,
                 &bpos);
        nfsm_fhtom(vp, 1);
        nfsm_build(tl, u_long *, 2 * NFSX_UNSIGNED);
        *tl++ = txdr_unsigned(rwflag);
        *tl = txdr_unsigned(nmp->nm_leaseterm);
        microtime(&now);
        reqtime = now.tv_sec;
        nfsm_request(vp, NQNFSPROC_GETLEASE, p, cred, &xid);
        np = VTONFS(vp);
        nfsm_dissect(tl, u_long *, 4 * NFSX_UNSIGNED);
        cachable = fxdr_unsigned(int, *tl++);
        reqtime += fxdr_unsigned(int, *tl++);
        microtime(&now);
        if (reqtime > now.tv_sec) {
                nmp = VFSTONFS(vp->v_mount);
                if (!nmp) {
                        error = ENXIO;
                } else {
                        fxdr_hyper(tl, &frev);
                        nqnfs_clientlease(nmp, np, rwflag, cachable,
                                reqtime, frev);
                        nfsm_loadattr(vp, (struct vattr *)0, &xid);
                }
        } else
                error = NQNFS_EXPIRED;
        nfsm_reqdone;
        return (error);
}

/*
 * Client vacated message function.
 */
static int
nqnfs_vacated(vp, cred)
        register struct vnode *vp;
        struct ucred *cred;
{
        register caddr_t cp;
        register struct mbuf *m;
        register int i;
        register u_long *tl;
        register long t2;
        caddr_t bpos;
        u_long xid;
        int error = 0;
        struct mbuf *mreq, *mb, *mb2, *mheadend;
        struct nfsmount *nmp;
        struct nfsreq myrep;
        int connrequired;
        int *flagp;

        nmp = VFSTONFS(vp->v_mount);
        if (!nmp)
                return (ENXIO);
        nfsstats.rpccnt[NQNFSPROC_VACATED]++;
        nfsm_reqhead(vp, NQNFSPROC_VACATED, NFSX_FH(1));
        nfsm_fhtom(vp, 1);
        m = mreq;
        i = 0;
        while (m) {
                i += m->m_len;
                m = m->m_next;
        }
        m = nfsm_rpchead(cred, nmp->nm_flag, NQNFSPROC_VACATED,
                RPCAUTH_UNIX, 5 * NFSX_UNSIGNED, (char *)0,
                0, (char *)NULL, mreq, i, &mheadend, &xid);
        if (nmp->nm_sotype == SOCK_STREAM) {
                M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
                *mtod(m, u_long *) = htonl(0x80000000 | (m->m_pkthdr.len -
                        NFSX_UNSIGNED));
        }
        myrep.r_flags = 0;
        myrep.r_nmp = nmp;

        connrequired = (nmp->nm_soflags & PR_CONNREQUIRED);
        if (connrequired)
                (void) nfs_sndlock(&myrep);

        (void) nfs_send(nmp->nm_so, nmp->nm_nam, m, &myrep);

        if (connrequired)
                nfs_sndunlock(&myrep);
nfsmout:
        return (error);
}

#ifndef NFS_NOSERVER 

/*
 * Called for client side callbacks
 */
int
nqnfs_callback(nmp, mrep, md, dpos)
        struct nfsmount *nmp;
        struct mbuf *mrep, *md;
        caddr_t dpos;
{
        register struct vnode *vp;
        register u_long *tl;
        register long t1;
        nfsfh_t nfh;
        fhandle_t *fhp;
        struct nfsnode *np;
        struct nfsd tnfsd;
        struct nfssvc_sock *slp;
        struct nfsrv_descript ndesc;
        register struct nfsrv_descript *nfsd = &ndesc;
        struct mbuf **mrq = (struct mbuf **)0, *mb, *mreq;
        int error = 0, cache = 0;
        char *cp2, *bpos;
        u_quad_t frev;

#ifndef nolint
        slp = NULL;
#endif
        nfsd->nd_mrep = mrep;
        nfsd->nd_md = md;
        nfsd->nd_dpos = dpos;
        error = nfs_getreq(nfsd, &tnfsd, FALSE);
        if (error)
                return (error);
        md = nfsd->nd_md;
        dpos = nfsd->nd_dpos;
        if (nfsd->nd_procnum != NQNFSPROC_EVICTED) {
                m_freem(mrep);
                return (EPERM);
        }
        fhp = &nfh.fh_generic;
        nfsm_srvmtofh(fhp);
        m_freem(mrep);
        error = nfs_nget(nmp->nm_mountp, (nfsfh_t *)fhp, NFSX_V3FH, &np);
        if (error)
                return (error);
        vp = NFSTOV(np);
        if (np->n_timer.cqe_next != 0) {
                np->n_expiry = 0;
                np->n_flag |= NQNFSEVICTED;
                if (nmp->nm_timerhead.cqh_first != np) {
                        CIRCLEQ_REMOVE(&nmp->nm_timerhead, np, n_timer);
                        CIRCLEQ_INSERT_HEAD(&nmp->nm_timerhead, np, n_timer);
                }
        }
        vput(vp);
        nfsm_srvdone;
}


/*
 * Nqnfs client helper daemon. Runs once a second to expire leases.
 * It also get authorization strings for "kerb" mounts.
 * It must start at the beginning of the list again after any potential
 * "sleep" since nfs_reclaim() called from vclean() can pull a node off
 * the list asynchronously.
 */
int
nqnfs_clientd(nmp, cred, ncd, flag, argp, p)
        register struct nfsmount *nmp;
        struct ucred *cred;
        struct nfsd_cargs *ncd;
        int flag;
        caddr_t argp;
        struct proc *p;
{
        register struct nfsnode *np;
        struct vnode *vp;
        struct nfsreq myrep;
        struct nfsuid *nuidp, *nnuidp;
        int error = 0, vpid;
        register struct nfsreq *rp;
        struct timeval now;

        /*
         * First initialize some variables
         */
        microtime(&now);

        /*
         * If an authorization string is being passed in, get it.
         */
        if ((flag & NFSSVC_GOTAUTH) &&
            (nmp->nm_state & (NFSSTA_WAITAUTH | NFSSTA_DISMNT)) == 0) {
            if (nmp->nm_state & NFSSTA_HASAUTH)
                panic("cld kerb");
            if ((flag & NFSSVC_AUTHINFAIL) == 0) {
                if (ncd->ncd_authlen <= nmp->nm_authlen &&
                    ncd->ncd_verflen <= nmp->nm_verflen &&
                    !copyin(ncd->ncd_authstr,nmp->nm_authstr,ncd->ncd_authlen)&&
                    !copyin(ncd->ncd_verfstr,nmp->nm_verfstr,ncd->ncd_verflen)){
                    nmp->nm_authtype = ncd->ncd_authtype;
                    nmp->nm_authlen = ncd->ncd_authlen;
                    nmp->nm_verflen = ncd->ncd_verflen;
#if NFSKERB
                    nmp->nm_key = ncd->ncd_key;
#endif
                } else
                    nmp->nm_state |= NFSSTA_AUTHERR;
            } else
                nmp->nm_state |= NFSSTA_AUTHERR;
            nmp->nm_state |= NFSSTA_HASAUTH;
            wakeup((caddr_t)&nmp->nm_authlen);
        } else
            nmp->nm_state |= NFSSTA_WAITAUTH;

        /*
         * Loop every second updating queue until there is a termination sig.
         */
        while ((nmp->nm_state & NFSSTA_DISMNT) == 0) {
            if (nmp->nm_flag & NFSMNT_NQNFS) {
                /*
                 * If there are no outstanding requests (and therefore no
                 * processes in nfs_reply) and there is data in the receive
                 * queue, poke for callbacks.
                 */
                if (nfs_reqq.tqh_first == 0 && nmp->nm_so &&
                    nmp->nm_so->so_rcv.sb_cc > 0) {
                    myrep.r_flags = R_GETONEREP;
                    myrep.r_nmp = nmp;
                    myrep.r_mrep = (struct mbuf *)0;
                    myrep.r_procp = (struct proc *)0;
                    (void) nfs_reply(&myrep);
                }

                /*
                 * Loop through the leases, updating as required.
                 */
                np = nmp->nm_timerhead.cqh_first;
                while (np != (void *)&nmp->nm_timerhead &&
                       (nmp->nm_state & NFSSTA_DISMINPROG) == 0) {
                        vp = NFSTOV(np);
                        vpid = vp->v_id;
                        if (np->n_expiry < now.tv_sec) {
                           if (vget(vp, LK_EXCLUSIVE, p) == 0) {
                             nmp->nm_inprog = vp;
                             if (vpid == vp->v_id) {
                                CIRCLEQ_REMOVE(&nmp->nm_timerhead, np, n_timer);
                                np->n_timer.cqe_next = 0;
                                if (np->n_flag & (NMODIFIED | NQNFSEVICTED)) {
                                        if (np->n_flag & NQNFSEVICTED) {
                                                if (vp->v_type == VDIR)
                                                        nfs_invaldir(vp);
                                                cache_purge(vp);
                                                (void) nfs_vinvalbuf(vp,
                                                       V_SAVE, cred, p, 0);
                                                np->n_flag &= ~NQNFSEVICTED;
                                                (void) nqnfs_vacated(vp, cred);
                                        } else if (vp->v_type == VREG) {
                                                (void) VOP_FSYNC(vp, cred,
                                                    MNT_WAIT, p);
                                                np->n_flag &= ~NMODIFIED;
                                        }
                                }
                              }
                              vrele(vp);
                              nmp->nm_inprog = NULLVP;
                            }
                        } else if ((np->n_expiry - NQ_RENEWAL) < now.tv_sec) {
                            if ((np->n_flag & (NQNFSWRITE | NQNFSNONCACHE))
                                 == NQNFSWRITE && np->n_dirtyblkhd.lh_first &&
                                 vget(vp, LK_EXCLUSIVE, p) == 0) {
                                 nmp->nm_inprog = vp;
                                 if (vpid == vp->v_id &&
                                     nqnfs_getlease(vp, ND_WRITE, cred, p)==0)
                                        np->n_brev = np->n_lrev;
                                 vrele(vp);
                                 nmp->nm_inprog = NULLVP;
                            }
                        } else
                                break;
                        if (np == nmp->nm_timerhead.cqh_first)
                                break;
                        np = nmp->nm_timerhead.cqh_first;
                }
            }

            /*
             * Get an authorization string, if required.
             */
            if ((nmp->nm_state & (NFSSTA_WAITAUTH | NFSSTA_DISMNT | NFSSTA_HASAUTH)) == 0) {
                ncd->ncd_authuid = nmp->nm_authuid;
                if (copyout((caddr_t)ncd, argp, sizeof (struct nfsd_cargs)))
                        nmp->nm_state |= NFSSTA_WAITAUTH;
                else
                        return (ENEEDAUTH);
            }

            /*
             * Wait a bit (no pun) and do it again.
             */
            if ((nmp->nm_state & NFSSTA_DISMNT) == 0 &&
                (nmp->nm_state & (NFSSTA_WAITAUTH | NFSSTA_HASAUTH))) {
                    error = tsleep((caddr_t)&nmp->nm_authstr, PSOCK | PCATCH,
                        "nqnfstimr", hz / 3);
                    if (error == EINTR || error == ERESTART)
                        (void) dounmount(nmp->nm_mountp, 0, p);
            }
        }

        /*
         * Finally, we can free up the mount structure.
         */
        for (nuidp = nmp->nm_uidlruhead.tqh_first; nuidp != 0; nuidp = nnuidp) {
                nnuidp = nuidp->nu_lru.tqe_next;
                LIST_REMOVE(nuidp, nu_hash);
                TAILQ_REMOVE(&nmp->nm_uidlruhead, nuidp, nu_lru);
                FREE_ZONE((caddr_t)nuidp, sizeof (struct nfsuid), M_NFSUID);
        }
        /*
         * Loop through outstanding request list and remove dangling
         * references to defunct nfsmount struct
         */
        for (rp = nfs_reqq.tqh_first; rp; rp = rp->r_chain.tqe_next)
                if (rp->r_nmp == nmp)
                        rp->r_nmp = (struct nfsmount *)0;
        FREE_ZONE((caddr_t)nmp, sizeof (struct nfsmount), M_NFSMNT);
        if (error == EWOULDBLOCK)
                error = 0;
        return (error);
}

#endif /* NFS_NOSERVER */

/*
 * Adjust all timer queue expiry times when the time of day clock is changed.
 * Called from the settimeofday() syscall.
 */
void
nqnfs_lease_updatetime(deltat)
        register int deltat;
{
        struct proc *p = current_proc();        /* XXX */
        struct nqlease *lp;
        struct nfsnode *np;
        struct mount *mp, *nxtmp;
        struct nfsmount *nmp;
        int s;

        if (nqnfsstarttime != 0)
                nqnfsstarttime += deltat;
        s = splsoftclock();
        for (lp = nqtimerhead.cqh_first; lp != (void *)&nqtimerhead;
            lp = lp->lc_timer.cqe_next)
                lp->lc_expiry += deltat;
        splx(s);

        /*
         * Search the mount list for all nqnfs mounts and do their timer
         * queues.
         */
        simple_lock(&mountlist_slock);
        for (mp = mountlist.cqh_first; mp != (void *)&mountlist; mp = nxtmp) {
                if (vfs_busy(mp, LK_NOWAIT, &mountlist_slock, p)) {
                        nxtmp = mp->mnt_list.cqe_next;
                        continue;
                }
                if (mp->mnt_stat.f_type == nfs_mount_type) {
                        nmp = VFSTONFS(mp);
                        if (nmp->nm_flag & NFSMNT_NQNFS) {
                                for (np = nmp->nm_timerhead.cqh_first;
                                    np != (void *)&nmp->nm_timerhead;
                                    np = np->n_timer.cqe_next) {
                                        np->n_expiry += deltat;
                                }
                        }
                }
                simple_lock(&mountlist_slock);
                nxtmp = mp->mnt_list.cqe_next;
                vfs_unbusy(mp, p);
        }
        simple_unlock(&mountlist_slock);
}

/*
 * Lock a server lease.
 */
static void
nqsrv_locklease(lp)
        struct nqlease *lp;
{

        while (lp->lc_flag & LC_LOCKED) {
                lp->lc_flag |= LC_WANTED;
                (void) tsleep((caddr_t)lp, PSOCK, "nqlc", 0);
        }
        lp->lc_flag |= LC_LOCKED;
        lp->lc_flag &= ~LC_WANTED;
}

/*
 * Unlock a server lease.
 */
static void
nqsrv_unlocklease(lp)
        struct nqlease *lp;
{

        lp->lc_flag &= ~LC_LOCKED;
        if (lp->lc_flag & LC_WANTED)
                wakeup((caddr_t)lp);
}

/*
 * Update a client lease.
 */
void
nqnfs_clientlease(nmp, np, rwflag, cachable, expiry, frev)
        register struct nfsmount *nmp;
        register struct nfsnode *np;
        int rwflag, cachable;
        time_t expiry;
        u_quad_t frev;
{
        register struct nfsnode *tp;

        if (np->n_timer.cqe_next != 0) {
                CIRCLEQ_REMOVE(&nmp->nm_timerhead, np, n_timer);
                if (rwflag == ND_WRITE)
                        np->n_flag |= NQNFSWRITE;
        } else if (rwflag == ND_READ)
                np->n_flag &= ~NQNFSWRITE;
        else
                np->n_flag |= NQNFSWRITE;
        if (cachable)
                np->n_flag &= ~NQNFSNONCACHE;
        else
                np->n_flag |= NQNFSNONCACHE;
        np->n_expiry = expiry;
        np->n_lrev = frev;
        tp = nmp->nm_timerhead.cqh_last;
        while (tp != (void *)&nmp->nm_timerhead && tp->n_expiry > np->n_expiry)
                tp = tp->n_timer.cqe_prev;
        if (tp == (void *)&nmp->nm_timerhead) {
                CIRCLEQ_INSERT_HEAD(&nmp->nm_timerhead, np, n_timer);
        } else {
                CIRCLEQ_INSERT_AFTER(&nmp->nm_timerhead, tp, np, n_timer);
        }
}