/*      $NetBSD: nfs_nfsdstate.c,v 1.6 2024/07/05 04:31:52 rin Exp $    */
/*-
 * Copyright (c) 2009 Rick Macklem, University of Guelph
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <sys/cdefs.h>
/* __FBSDID("FreeBSD: head/sys/fs/nfsserver/nfs_nfsdstate.c 307694 2016-10-20 23:53:16Z rmacklem "); */
__RCSID("$NetBSD: nfs_nfsdstate.c,v 1.6 2024/07/05 04:31:52 rin Exp $");

#ifndef APPLEKEXT
#include <fs/nfs/common/nfsport.h>

struct nfsrv_stablefirst nfsrv_stablefirst;
int nfsrv_issuedelegs = 0;
int nfsrv_dolocallocks = 0;
struct nfsv4lock nfsv4rootfs_lock;

extern int newnfs_numnfsd;
extern struct nfsstatsv1 nfsstatsv1;
extern int nfsrv_lease;
extern struct timeval nfsboottime;
extern u_int32_t newnfs_true, newnfs_false;
NFSV4ROOTLOCKMUTEX;
NFSSTATESPINLOCK;

SYSCTL_DECL(_vfs_nfsd);
int     nfsrv_statehashsize = NFSSTATEHASHSIZE;
SYSCTL_INT(_vfs_nfsd, OID_AUTO, statehashsize, CTLFLAG_RDTUN,
    &nfsrv_statehashsize, 0,
    "Size of state hash table set via loader.conf");

int     nfsrv_clienthashsize = NFSCLIENTHASHSIZE;
SYSCTL_INT(_vfs_nfsd, OID_AUTO, clienthashsize, CTLFLAG_RDTUN,
    &nfsrv_clienthashsize, 0,
    "Size of client hash table set via loader.conf");

int     nfsrv_lockhashsize = NFSLOCKHASHSIZE;
SYSCTL_INT(_vfs_nfsd, OID_AUTO, fhhashsize, CTLFLAG_RDTUN,
    &nfsrv_lockhashsize, 0,
    "Size of file handle hash table set via loader.conf");

int     nfsrv_sessionhashsize = NFSSESSIONHASHSIZE;
SYSCTL_INT(_vfs_nfsd, OID_AUTO, sessionhashsize, CTLFLAG_RDTUN,
    &nfsrv_sessionhashsize, 0,
    "Size of session hash table set via loader.conf");

static int      nfsrv_v4statelimit = NFSRV_V4STATELIMIT;
SYSCTL_INT(_vfs_nfsd, OID_AUTO, v4statelimit, CTLFLAG_RWTUN,
    &nfsrv_v4statelimit, 0,
    "High water limit for NFSv4 opens+locks+delegations");

static int      nfsrv_writedelegifpos = 0;
SYSCTL_INT(_vfs_nfsd, OID_AUTO, writedelegifpos, CTLFLAG_RW,
    &nfsrv_writedelegifpos, 0,
    "Issue a write delegation for read opens if possible");

/*
 * Hash lists for nfs V4.
 */
struct nfsclienthashhead        *nfsclienthash;
struct nfslockhashhead          *nfslockhash;
struct nfssessionhash           *nfssessionhash;
#endif  /* !APPLEKEXT */

static u_int32_t nfsrv_openpluslock = 0, nfsrv_delegatecnt = 0;
static time_t nfsrvboottime;
static int nfsrv_returnoldstateid = 0, nfsrv_clients = 0;
static int nfsrv_clienthighwater = NFSRV_CLIENTHIGHWATER;
static int nfsrv_nogsscallback = 0;

/* local functions */
static void nfsrv_dumpaclient(struct nfsclient *clp,
    struct nfsd_dumpclients *dumpp);
static void nfsrv_freeopenowner(struct nfsstate *stp, int cansleep,
    NFSPROC_T *p);
static int nfsrv_freeopen(struct nfsstate *stp, vnode_t vp, int cansleep,
    NFSPROC_T *p);
static void nfsrv_freelockowner(struct nfsstate *stp, vnode_t vp, int cansleep,
    NFSPROC_T *p);
static void nfsrv_freeallnfslocks(struct nfsstate *stp, vnode_t vp,
    int cansleep, NFSPROC_T *p);
static void nfsrv_freenfslock(struct nfslock *lop);
static void nfsrv_freenfslockfile(struct nfslockfile *lfp);
static void nfsrv_freedeleg(struct nfsstate *);
static int nfsrv_getstate(struct nfsclient *clp, nfsv4stateid_t *stateidp, 
    u_int32_t flags, struct nfsstate **stpp);
static void nfsrv_getowner(struct nfsstatehead *hp, struct nfsstate *new_stp,
    struct nfsstate **stpp);
static int nfsrv_getlockfh(vnode_t vp, u_short flags,
    struct nfslockfile *new_lfp, fhandle_t *nfhp, NFSPROC_T *p);
static int nfsrv_getlockfile(u_short flags, struct nfslockfile **new_lfpp,
    struct nfslockfile **lfpp, fhandle_t *nfhp, int lockit);
static void nfsrv_insertlock(struct nfslock *new_lop,
    struct nfslock *insert_lop, struct nfsstate *stp, struct nfslockfile *lfp);
static void nfsrv_updatelock(struct nfsstate *stp, struct nfslock **new_lopp,
    struct nfslock **other_lopp, struct nfslockfile *lfp);
static int nfsrv_getipnumber(u_char *cp);
static int nfsrv_checkrestart(nfsquad_t clientid, u_int32_t flags,
    nfsv4stateid_t *stateidp, int specialid);
static int nfsrv_checkgrace(struct nfsrv_descript *nd, struct nfsclient *clp,
    u_int32_t flags);
static int nfsrv_docallback(struct nfsclient *clp, int procnum,
    nfsv4stateid_t *stateidp, int trunc, fhandle_t *fhp,
    struct nfsvattr *nap, nfsattrbit_t *attrbitp, NFSPROC_T *p);
static int nfsrv_cbcallargs(struct nfsrv_descript *nd, struct nfsclient *clp,
    uint32_t callback, int op, const char *optag, struct nfsdsession **sepp);
static u_int32_t nfsrv_nextclientindex(void);
static u_int32_t nfsrv_nextstateindex(struct nfsclient *clp);
static void nfsrv_markstable(struct nfsclient *clp);
static int nfsrv_checkstable(struct nfsclient *clp);
static int nfsrv_clientconflict(struct nfsclient *clp, int *haslockp, struct 
    vnode *vp, NFSPROC_T *p);
static int nfsrv_delegconflict(struct nfsstate *stp, int *haslockp,
    NFSPROC_T *p, vnode_t vp);
static int nfsrv_cleandeleg(vnode_t vp, struct nfslockfile *lfp,
    struct nfsclient *clp, int *haslockp, NFSPROC_T *p);
static int nfsrv_notsamecredname(struct nfsrv_descript *nd,
    struct nfsclient *clp);
static time_t nfsrv_leaseexpiry(void);
static void nfsrv_delaydelegtimeout(struct nfsstate *stp);
static int nfsrv_checkseqid(struct nfsrv_descript *nd, u_int32_t seqid,
    struct nfsstate *stp, struct nfsrvcache *op);
static int nfsrv_nootherstate(struct nfsstate *stp);
static int nfsrv_locallock(vnode_t vp, struct nfslockfile *lfp, int flags,
    uint64_t first, uint64_t end, struct nfslockconflict *cfp, NFSPROC_T *p);
static void nfsrv_localunlock(vnode_t vp, struct nfslockfile *lfp,
    uint64_t init_first, uint64_t init_end, NFSPROC_T *p);
static int nfsrv_dolocal(vnode_t vp, struct nfslockfile *lfp, int flags,
    int oldflags, uint64_t first, uint64_t end, struct nfslockconflict *cfp,
    NFSPROC_T *p);
static void nfsrv_locallock_rollback(vnode_t vp, struct nfslockfile *lfp,
    NFSPROC_T *p);
static void nfsrv_locallock_commit(struct nfslockfile *lfp, int flags,
    uint64_t first, uint64_t end);
static void nfsrv_locklf(struct nfslockfile *lfp);
static void nfsrv_unlocklf(struct nfslockfile *lfp);
static struct nfsdsession *nfsrv_findsession(uint8_t *sessionid);
static int nfsrv_freesession(struct nfsdsession *sep, uint8_t *sessionid);
static int nfsv4_setcbsequence(struct nfsrv_descript *nd, struct nfsclient *clp,
    int dont_replycache, struct nfsdsession **sepp);
static int nfsv4_getcbsession(struct nfsclient *clp, struct nfsdsession **sepp);

/*
 * Scan the client list for a match and either return the current one,
 * create a new entry or return an error.
 * If returning a non-error, the clp structure must either be linked into
 * the client list or free'd.
 */
APPLESTATIC int
nfsrv_setclient(struct nfsrv_descript *nd, struct nfsclient **new_clpp,
    nfsquad_t *clientidp, nfsquad_t *confirmp, NFSPROC_T *p)
{
        struct nfsclient *clp = NULL, *new_clp = *new_clpp;
        int i, error = 0;
        struct nfsstate *stp, *tstp;
        struct sockaddr_in *sad, *rad;
        int zapit = 0, gotit, hasstate = 0, igotlock;
        static u_int64_t confirm_index = 0;

        /*
         * Check for state resource limit exceeded.
         */
        if (nfsrv_openpluslock > nfsrv_v4statelimit) {
                error = NFSERR_RESOURCE;
                goto out;
        }

        if (nfsrv_issuedelegs == 0 ||
            ((nd->nd_flag & ND_GSS) != 0 && nfsrv_nogsscallback != 0))
                /*
                 * Don't do callbacks when delegations are disabled or
                 * for AUTH_GSS unless enabled via nfsrv_nogsscallback.
                 * If establishing a callback connection is attempted
                 * when a firewall is blocking the callback path, the
                 * server may wait too long for the connect attempt to
                 * succeed during the Open. Some clients, such as Linux,
                 * may timeout and give up on the Open before the server
                 * replies. Also, since AUTH_GSS callbacks are not
                 * yet interoperability tested, they might cause the
                 * server to crap out, if they get past the Init call to
                 * the client.
                 */
                new_clp->lc_program = 0;

        /* Lock out other nfsd threads */
        NFSLOCKV4ROOTMUTEX();
        nfsv4_relref(&nfsv4rootfs_lock);
        do {
                igotlock = nfsv4_lock(&nfsv4rootfs_lock, 1, NULL,
                    NFSV4ROOTLOCKMUTEXPTR, NULL);
        } while (!igotlock);
        NFSUNLOCKV4ROOTMUTEX();

        /*
         * Search for a match in the client list.
         */
        gotit = i = 0;
        while (i < nfsrv_clienthashsize && !gotit) {
            LIST_FOREACH(clp, &nfsclienthash[i], lc_hash) {
                if (new_clp->lc_idlen == clp->lc_idlen &&
                    !NFSBCMP(new_clp->lc_id, clp->lc_id, clp->lc_idlen)) {
                        gotit = 1;
                        break;
                }
            }
            if (gotit == 0)
                i++;
        }
        if (!gotit ||
            (clp->lc_flags & (LCL_NEEDSCONFIRM | LCL_ADMINREVOKED))) {
                if ((nd->nd_flag & ND_NFSV41) != 0 && confirmp->lval[1] != 0) {
                        /*
                         * For NFSv4.1, if confirmp->lval[1] is non-zero, the
                         * client is trying to update a confirmed clientid.
                         */
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                        confirmp->lval[1] = 0;
                        error = NFSERR_NOENT;
                        goto out;
                }
                /*
                 * Get rid of the old one.
                 */
                if (i != nfsrv_clienthashsize) {
                        LIST_REMOVE(clp, lc_hash);
                        nfsrv_cleanclient(clp, p);
                        nfsrv_freedeleglist(&clp->lc_deleg);
                        nfsrv_freedeleglist(&clp->lc_olddeleg);
                        zapit = 1;
                }
                /*
                 * Add it after assigning a client id to it.
                 */
                new_clp->lc_flags |= LCL_NEEDSCONFIRM;
                if ((nd->nd_flag & ND_NFSV41) != 0)
                        new_clp->lc_confirm.lval[0] = confirmp->lval[0] =
                            ++confirm_index;
                else
                        confirmp->qval = new_clp->lc_confirm.qval =
                            ++confirm_index;
                clientidp->lval[0] = new_clp->lc_clientid.lval[0] =
                    (u_int32_t)nfsrvboottime;
                clientidp->lval[1] = new_clp->lc_clientid.lval[1] =
                    nfsrv_nextclientindex();
                new_clp->lc_stateindex = 0;
                new_clp->lc_statemaxindex = 0;
                new_clp->lc_cbref = 0;
                new_clp->lc_expiry = nfsrv_leaseexpiry();
                LIST_INIT(&new_clp->lc_open);
                LIST_INIT(&new_clp->lc_deleg);
                LIST_INIT(&new_clp->lc_olddeleg);
                LIST_INIT(&new_clp->lc_session);
                for (i = 0; i < nfsrv_statehashsize; i++)
                        LIST_INIT(&new_clp->lc_stateid[i]);
                LIST_INSERT_HEAD(NFSCLIENTHASH(new_clp->lc_clientid), new_clp,
                    lc_hash);
                nfsstatsv1.srvclients++;
                nfsrv_openpluslock++;
                nfsrv_clients++;
                NFSLOCKV4ROOTMUTEX();
                nfsv4_unlock(&nfsv4rootfs_lock, 1);
                NFSUNLOCKV4ROOTMUTEX();
                if (zapit)
                        nfsrv_zapclient(clp, p);
                *new_clpp = NULL;
                goto out;
        }

        /*
         * Now, handle the cases where the id is already issued.
         */
        if (nfsrv_notsamecredname(nd, clp)) {
            /*
             * Check to see if there is expired state that should go away.
             */
            if (clp->lc_expiry < NFSD_MONOSEC &&
                (!LIST_EMPTY(&clp->lc_open) || !LIST_EMPTY(&clp->lc_deleg))) {
                nfsrv_cleanclient(clp, p);
                nfsrv_freedeleglist(&clp->lc_deleg);
            }

            /*
             * If there is outstanding state, then reply NFSERR_CLIDINUSE per
             * RFC3530 Sec. 8.1.2 last para.
             */
            if (!LIST_EMPTY(&clp->lc_deleg)) {
                hasstate = 1;
            } else if (LIST_EMPTY(&clp->lc_open)) {
                hasstate = 0;
            } else {
                hasstate = 0;
                /* Look for an Open on the OpenOwner */
                LIST_FOREACH(stp, &clp->lc_open, ls_list) {
                    if (!LIST_EMPTY(&stp->ls_open)) {
                        hasstate = 1;
                        break;
                    }
                }
            }
            if (hasstate) {
                /*
                 * If the uid doesn't match, return NFSERR_CLIDINUSE after
                 * filling out the correct ipaddr and portnum.
                 */
                sad = NFSSOCKADDR(new_clp->lc_req.nr_nam, struct sockaddr_in *);
                rad = NFSSOCKADDR(clp->lc_req.nr_nam, struct sockaddr_in *);
                sad->sin_addr.s_addr = rad->sin_addr.s_addr;
                sad->sin_port = rad->sin_port;
                NFSLOCKV4ROOTMUTEX();
                nfsv4_unlock(&nfsv4rootfs_lock, 1);
                NFSUNLOCKV4ROOTMUTEX();
                error = NFSERR_CLIDINUSE;
                goto out;
            }
        }

        if (NFSBCMP(new_clp->lc_verf, clp->lc_verf, NFSX_VERF)) {
                /*
                 * If the verifier has changed, the client has rebooted
                 * and a new client id is issued. The old state info
                 * can be thrown away once the SETCLIENTID_CONFIRM occurs.
                 */
                LIST_REMOVE(clp, lc_hash);
                new_clp->lc_flags |= LCL_NEEDSCONFIRM;
                if ((nd->nd_flag & ND_NFSV41) != 0)
                        new_clp->lc_confirm.lval[0] = confirmp->lval[0] =
                            ++confirm_index;
                else
                        confirmp->qval = new_clp->lc_confirm.qval =
                            ++confirm_index;
                clientidp->lval[0] = new_clp->lc_clientid.lval[0] =
                    nfsrvboottime;
                clientidp->lval[1] = new_clp->lc_clientid.lval[1] =
                    nfsrv_nextclientindex();
                new_clp->lc_stateindex = 0;
                new_clp->lc_statemaxindex = 0;
                new_clp->lc_cbref = 0;
                new_clp->lc_expiry = nfsrv_leaseexpiry();

                /*
                 * Save the state until confirmed.
                 */
                LIST_NEWHEAD(&new_clp->lc_open, &clp->lc_open, ls_list);
                LIST_FOREACH(tstp, &new_clp->lc_open, ls_list)
                        tstp->ls_clp = new_clp;
                LIST_NEWHEAD(&new_clp->lc_deleg, &clp->lc_deleg, ls_list);
                LIST_FOREACH(tstp, &new_clp->lc_deleg, ls_list)
                        tstp->ls_clp = new_clp;
                LIST_NEWHEAD(&new_clp->lc_olddeleg, &clp->lc_olddeleg,
                    ls_list);
                LIST_FOREACH(tstp, &new_clp->lc_olddeleg, ls_list)
                        tstp->ls_clp = new_clp;
                for (i = 0; i < nfsrv_statehashsize; i++) {
                        LIST_NEWHEAD(&new_clp->lc_stateid[i],
                            &clp->lc_stateid[i], ls_hash);
                        LIST_FOREACH(tstp, &new_clp->lc_stateid[i], ls_hash)
                                tstp->ls_clp = new_clp;
                }
                LIST_INSERT_HEAD(NFSCLIENTHASH(new_clp->lc_clientid), new_clp,
                    lc_hash);
                nfsstatsv1.srvclients++;
                nfsrv_openpluslock++;
                nfsrv_clients++;
                NFSLOCKV4ROOTMUTEX();
                nfsv4_unlock(&nfsv4rootfs_lock, 1);
                NFSUNLOCKV4ROOTMUTEX();

                /*
                 * Must wait until any outstanding callback on the old clp
                 * completes.
                 */
                NFSLOCKSTATE();
                while (clp->lc_cbref) {
                        clp->lc_flags |= LCL_WAKEUPWANTED;
                        (void)mtx_sleep(clp, NFSSTATEMUTEXPTR, PZERO - 1,
                            "nfsd clp", 10 * hz);
                }
                NFSUNLOCKSTATE();
                nfsrv_zapclient(clp, p);
                *new_clpp = NULL;
                goto out;
        }

        /* For NFSv4.1, mark that we found a confirmed clientid. */
        if ((nd->nd_flag & ND_NFSV41) != 0) {
                clientidp->lval[0] = clp->lc_clientid.lval[0];
                clientidp->lval[1] = clp->lc_clientid.lval[1];
                confirmp->lval[0] = 0;  /* Ignored by client */
                confirmp->lval[1] = 1;
        } else {
                /*
                 * id and verifier match, so update the net address info
                 * and get rid of any existing callback authentication
                 * handle, so a new one will be acquired.
                 */
                LIST_REMOVE(clp, lc_hash);
                new_clp->lc_flags |= (LCL_NEEDSCONFIRM | LCL_DONTCLEAN);
                new_clp->lc_expiry = nfsrv_leaseexpiry();
                confirmp->qval = new_clp->lc_confirm.qval = ++confirm_index;
                clientidp->lval[0] = new_clp->lc_clientid.lval[0] =
                    clp->lc_clientid.lval[0];
                clientidp->lval[1] = new_clp->lc_clientid.lval[1] =
                    clp->lc_clientid.lval[1];
                new_clp->lc_delegtime = clp->lc_delegtime;
                new_clp->lc_stateindex = clp->lc_stateindex;
                new_clp->lc_statemaxindex = clp->lc_statemaxindex;
                new_clp->lc_cbref = 0;
                LIST_NEWHEAD(&new_clp->lc_open, &clp->lc_open, ls_list);
                LIST_FOREACH(tstp, &new_clp->lc_open, ls_list)
                        tstp->ls_clp = new_clp;
                LIST_NEWHEAD(&new_clp->lc_deleg, &clp->lc_deleg, ls_list);
                LIST_FOREACH(tstp, &new_clp->lc_deleg, ls_list)
                        tstp->ls_clp = new_clp;
                LIST_NEWHEAD(&new_clp->lc_olddeleg, &clp->lc_olddeleg, ls_list);
                LIST_FOREACH(tstp, &new_clp->lc_olddeleg, ls_list)
                        tstp->ls_clp = new_clp;
                for (i = 0; i < nfsrv_statehashsize; i++) {
                        LIST_NEWHEAD(&new_clp->lc_stateid[i],
                            &clp->lc_stateid[i], ls_hash);
                        LIST_FOREACH(tstp, &new_clp->lc_stateid[i], ls_hash)
                                tstp->ls_clp = new_clp;
                }
                LIST_INSERT_HEAD(NFSCLIENTHASH(new_clp->lc_clientid), new_clp,
                    lc_hash);
                nfsstatsv1.srvclients++;
                nfsrv_openpluslock++;
                nfsrv_clients++;
        }
        NFSLOCKV4ROOTMUTEX();
        nfsv4_unlock(&nfsv4rootfs_lock, 1);
        NFSUNLOCKV4ROOTMUTEX();

        if ((nd->nd_flag & ND_NFSV41) == 0) {
                /*
                 * Must wait until any outstanding callback on the old clp
                 * completes.
                 */
                NFSLOCKSTATE();
                while (clp->lc_cbref) {
                        clp->lc_flags |= LCL_WAKEUPWANTED;
                        (void)mtx_sleep(clp, NFSSTATEMUTEXPTR, PZERO - 1,
                            "nfsdclp", 10 * hz);
                }
                NFSUNLOCKSTATE();
                nfsrv_zapclient(clp, p);
                *new_clpp = NULL;
        }

out:
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Check to see if the client id exists and optionally confirm it.
 */
APPLESTATIC int
nfsrv_getclient(nfsquad_t clientid, int opflags, struct nfsclient **clpp,
    struct nfsdsession *nsep, nfsquad_t confirm, uint32_t cbprogram,
    struct nfsrv_descript *nd, NFSPROC_T *p)
{
        struct nfsclient *clp;
        struct nfsstate *stp;
        int i;
        struct nfsclienthashhead *hp;
        int error = 0, igotlock, doneok;
        struct nfssessionhash *shp;
        struct nfsdsession *sep;
        uint64_t sessid[2];
        static uint64_t next_sess = 0;

        if (clpp)
                *clpp = NULL;
        if ((nd == NULL || (nd->nd_flag & ND_NFSV41) == 0 ||
            opflags != CLOPS_RENEW) && nfsrvboottime != clientid.lval[0]) {
                error = NFSERR_STALECLIENTID;
                goto out;
        }

        /*
         * If called with opflags == CLOPS_RENEW, the State Lock is
         * already held. Otherwise, we need to get either that or,
         * for the case of Confirm, lock out the nfsd threads.
         */
        if (opflags & CLOPS_CONFIRM) {
                NFSLOCKV4ROOTMUTEX();
                nfsv4_relref(&nfsv4rootfs_lock);
                do {
                        igotlock = nfsv4_lock(&nfsv4rootfs_lock, 1, NULL,
                            NFSV4ROOTLOCKMUTEXPTR, NULL);
                } while (!igotlock);
                /*
                 * Create a new sessionid here, since we need to do it where
                 * there is a mutex held to serialize update of next_sess.
                 */
                if ((nd->nd_flag & ND_NFSV41) != 0) {
                        sessid[0] = ++next_sess;
                        sessid[1] = clientid.qval;
                }
                NFSUNLOCKV4ROOTMUTEX();
        } else if (opflags != CLOPS_RENEW) {
                NFSLOCKSTATE();
        }

        /* For NFSv4.1, the clp is acquired from the associated session. */
        if (nd != NULL && (nd->nd_flag & ND_NFSV41) != 0 &&
            opflags == CLOPS_RENEW) {
                clp = NULL;
                if ((nd->nd_flag & ND_HASSEQUENCE) != 0) {
                        shp = NFSSESSIONHASH(nd->nd_sessionid);
                        NFSLOCKSESSION(shp);
                        sep = nfsrv_findsession(nd->nd_sessionid);
                        if (sep != NULL)
                                clp = sep->sess_clp;
                        NFSUNLOCKSESSION(shp);
                }
        } else {
                hp = NFSCLIENTHASH(clientid);
                LIST_FOREACH(clp, hp, lc_hash) {
                        if (clp->lc_clientid.lval[1] == clientid.lval[1])
                                break;
                }
        }
        if (clp == NULL) {
                if (opflags & CLOPS_CONFIRM)
                        error = NFSERR_STALECLIENTID;
                else
                        error = NFSERR_EXPIRED;
        } else if (clp->lc_flags & LCL_ADMINREVOKED) {
                /*
                 * If marked admin revoked, just return the error.
                 */
                error = NFSERR_ADMINREVOKED;
        }
        if (error) {
                if (opflags & CLOPS_CONFIRM) {
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                } else if (opflags != CLOPS_RENEW) {
                        NFSUNLOCKSTATE();
                }
                goto out;
        }

        /*
         * Perform any operations specified by the opflags.
         */
        if (opflags & CLOPS_CONFIRM) {
                if (((nd->nd_flag & ND_NFSV41) != 0 &&
                     clp->lc_confirm.lval[0] != confirm.lval[0]) ||
                    ((nd->nd_flag & ND_NFSV41) == 0 &&
                     clp->lc_confirm.qval != confirm.qval))
                        error = NFSERR_STALECLIENTID;
                else if (nfsrv_notsamecredname(nd, clp))
                        error = NFSERR_CLIDINUSE;

                if (!error) {
                    if ((clp->lc_flags & (LCL_NEEDSCONFIRM | LCL_DONTCLEAN)) ==
                        LCL_NEEDSCONFIRM) {
                        /*
                         * Hang onto the delegations (as old delegations)
                         * for an Open with CLAIM_DELEGATE_PREV unless in
                         * grace, but get rid of the rest of the state.
                         */
                        nfsrv_cleanclient(clp, p);
                        nfsrv_freedeleglist(&clp->lc_olddeleg);
                        if (nfsrv_checkgrace(nd, clp, 0)) {
                            /* In grace, so just delete delegations */
                            nfsrv_freedeleglist(&clp->lc_deleg);
                        } else {
                            LIST_FOREACH(stp, &clp->lc_deleg, ls_list)
                                stp->ls_flags |= NFSLCK_OLDDELEG;
                            clp->lc_delegtime = NFSD_MONOSEC +
                                nfsrv_lease + NFSRV_LEASEDELTA;
                            LIST_NEWHEAD(&clp->lc_olddeleg, &clp->lc_deleg,
                                ls_list);
                        }
                        if ((nd->nd_flag & ND_NFSV41) != 0)
                            clp->lc_program = cbprogram;
                    }
                    clp->lc_flags &= ~(LCL_NEEDSCONFIRM | LCL_DONTCLEAN);
                    if (clp->lc_program)
                        clp->lc_flags |= LCL_NEEDSCBNULL;
                    /* For NFSv4.1, link the session onto the client. */
                    if (nsep != NULL) {
                        /* Hold a reference on the xprt for a backchannel. */
                        if ((nsep->sess_crflags & NFSV4CRSESS_CONNBACKCHAN)
                            != 0 && clp->lc_req.nr_client == NULL) {
                            clp->lc_req.nr_client = (struct __rpc_client *)
                                clnt_bck_create(nd->nd_xprt->xp_socket,
                                cbprogram, NFSV4_CBVERS);
                            if (clp->lc_req.nr_client != NULL) {
                                SVC_ACQUIRE(nd->nd_xprt);
                                nd->nd_xprt->xp_p2 =
                                    clp->lc_req.nr_client->cl_private;
                                /* Disable idle timeout. */
                                nd->nd_xprt->xp_idletimeout = 0;
                                nsep->sess_cbsess.nfsess_xprt = nd->nd_xprt;
                            } else
                                nsep->sess_crflags &= ~NFSV4CRSESS_CONNBACKCHAN;
                        }
                        NFSBCOPY(sessid, nsep->sess_sessionid,
                            NFSX_V4SESSIONID);
                        NFSBCOPY(sessid, nsep->sess_cbsess.nfsess_sessionid,
                            NFSX_V4SESSIONID);
                        shp = NFSSESSIONHASH(nsep->sess_sessionid);
                        NFSLOCKSTATE();
                        NFSLOCKSESSION(shp);
                        LIST_INSERT_HEAD(&shp->list, nsep, sess_hash);
                        LIST_INSERT_HEAD(&clp->lc_session, nsep, sess_list);
                        nsep->sess_clp = clp;
                        NFSUNLOCKSESSION(shp);
                        NFSUNLOCKSTATE();
                    }
                }
        } else if (clp->lc_flags & LCL_NEEDSCONFIRM) {
                error = NFSERR_EXPIRED;
        }

        /*
         * If called by the Renew Op, we must check the principal.
         */
        if (!error && (opflags & CLOPS_RENEWOP)) {
            if (nfsrv_notsamecredname(nd, clp)) {
                doneok = 0;
                for (i = 0; i < nfsrv_statehashsize && doneok == 0; i++) {
                    LIST_FOREACH(stp, &clp->lc_stateid[i], ls_hash) {
                        if ((stp->ls_flags & NFSLCK_OPEN) &&
                            stp->ls_uid == nd->nd_cred->cr_uid) {
                                doneok = 1;
                                break;
                        }
                    }
                }
                if (!doneok)
                        error = NFSERR_ACCES;
            }
            if (!error && (clp->lc_flags & LCL_CBDOWN))
                error = NFSERR_CBPATHDOWN;
        }
        if ((!error || error == NFSERR_CBPATHDOWN) &&
             (opflags & CLOPS_RENEW)) {
                clp->lc_expiry = nfsrv_leaseexpiry();
        }
        if (opflags & CLOPS_CONFIRM) {
                NFSLOCKV4ROOTMUTEX();
                nfsv4_unlock(&nfsv4rootfs_lock, 1);
                NFSUNLOCKV4ROOTMUTEX();
        } else if (opflags != CLOPS_RENEW) {
                NFSUNLOCKSTATE();
        }
        if (clpp)
                *clpp = clp;

out:
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Perform the NFSv4.1 destroy clientid.
 */
int
nfsrv_destroyclient(nfsquad_t clientid, NFSPROC_T *p)
{
        struct nfsclient *clp;
        struct nfsclienthashhead *hp;
        int error = 0, i, igotlock;

        if (nfsrvboottime != clientid.lval[0]) {
                error = NFSERR_STALECLIENTID;
                goto out;
        }

        /* Lock out other nfsd threads */
        NFSLOCKV4ROOTMUTEX();
        nfsv4_relref(&nfsv4rootfs_lock);
        do {
                igotlock = nfsv4_lock(&nfsv4rootfs_lock, 1, NULL,
                    NFSV4ROOTLOCKMUTEXPTR, NULL);
        } while (igotlock == 0);
        NFSUNLOCKV4ROOTMUTEX();

        hp = NFSCLIENTHASH(clientid);
        LIST_FOREACH(clp, hp, lc_hash) {
                if (clp->lc_clientid.lval[1] == clientid.lval[1])
                        break;
        }
        if (clp == NULL) {
                NFSLOCKV4ROOTMUTEX();
                nfsv4_unlock(&nfsv4rootfs_lock, 1);
                NFSUNLOCKV4ROOTMUTEX();
                /* Just return ok, since it is gone. */
                goto out;
        }

        /* Scan for state on the clientid. */
        for (i = 0; i < nfsrv_statehashsize; i++)
                if (!LIST_EMPTY(&clp->lc_stateid[i])) {
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                        error = NFSERR_CLIENTIDBUSY;
                        goto out;
                }
        if (!LIST_EMPTY(&clp->lc_session) || !LIST_EMPTY(&clp->lc_deleg)) {
                NFSLOCKV4ROOTMUTEX();
                nfsv4_unlock(&nfsv4rootfs_lock, 1);
                NFSUNLOCKV4ROOTMUTEX();
                error = NFSERR_CLIENTIDBUSY;
                goto out;
        }

        /* Destroy the clientid and return ok. */
        nfsrv_cleanclient(clp, p);
        nfsrv_freedeleglist(&clp->lc_deleg);
        nfsrv_freedeleglist(&clp->lc_olddeleg);
        LIST_REMOVE(clp, lc_hash);
        NFSLOCKV4ROOTMUTEX();
        nfsv4_unlock(&nfsv4rootfs_lock, 1);
        NFSUNLOCKV4ROOTMUTEX();
        nfsrv_zapclient(clp, p);
out:
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Called from the new nfssvc syscall to admin revoke a clientid.
 * Returns 0 for success, error otherwise.
 */
APPLESTATIC int
nfsrv_adminrevoke(struct nfsd_clid *revokep, NFSPROC_T *p)
{
        struct nfsclient *clp = NULL;
        int i, error = 0;
        int gotit, igotlock;

        /*
         * First, lock out the nfsd so that state won't change while the
         * revocation record is being written to the stable storage restart
         * file.
         */
        NFSLOCKV4ROOTMUTEX();
        do {
                igotlock = nfsv4_lock(&nfsv4rootfs_lock, 1, NULL,
                    NFSV4ROOTLOCKMUTEXPTR, NULL);
        } while (!igotlock);
        NFSUNLOCKV4ROOTMUTEX();

        /*
         * Search for a match in the client list.
         */
        gotit = i = 0;
        while (i < nfsrv_clienthashsize && !gotit) {
            LIST_FOREACH(clp, &nfsclienthash[i], lc_hash) {
                if (revokep->nclid_idlen == clp->lc_idlen &&
                    !NFSBCMP(revokep->nclid_id, clp->lc_id, clp->lc_idlen)) {
                        gotit = 1;
                        break;
                }
            }
            i++;
        }
        if (!gotit) {
                NFSLOCKV4ROOTMUTEX();
                nfsv4_unlock(&nfsv4rootfs_lock, 0);
                NFSUNLOCKV4ROOTMUTEX();
                error = EPERM;
                goto out;
        }

        /*
         * Now, write out the revocation record
         */
        nfsrv_writestable(clp->lc_id, clp->lc_idlen, NFSNST_REVOKE, p);
        nfsrv_backupstable();

        /*
         * and clear out the state, marking the clientid revoked.
         */
        clp->lc_flags &= ~LCL_CALLBACKSON;
        clp->lc_flags |= LCL_ADMINREVOKED;
        nfsrv_cleanclient(clp, p);
        nfsrv_freedeleglist(&clp->lc_deleg);
        nfsrv_freedeleglist(&clp->lc_olddeleg);
        NFSLOCKV4ROOTMUTEX();
        nfsv4_unlock(&nfsv4rootfs_lock, 0);
        NFSUNLOCKV4ROOTMUTEX();

out:
        NFSEXITCODE(error);
        return (error);
}

/*
 * Dump out stats for all clients. Called from nfssvc(2), that is used
 * nfsstatsv1.
 */
APPLESTATIC void
nfsrv_dumpclients(struct nfsd_dumpclients *dumpp, int maxcnt)
{
        struct nfsclient *clp;
        int i = 0, cnt = 0;

        /*
         * First, get a reference on the nfsv4rootfs_lock so that an
         * exclusive lock cannot be acquired while dumping the clients.
         */
        NFSLOCKV4ROOTMUTEX();
        nfsv4_getref(&nfsv4rootfs_lock, NULL, NFSV4ROOTLOCKMUTEXPTR, NULL);
        NFSUNLOCKV4ROOTMUTEX();
        NFSLOCKSTATE();
        /*
         * Rattle through the client lists until done.
         */
        while (i < nfsrv_clienthashsize && cnt < maxcnt) {
            clp = LIST_FIRST(&nfsclienthash[i]);
            while (clp != NULL && cnt < maxcnt) {
                nfsrv_dumpaclient(clp, &dumpp[cnt]);
                cnt++;
                clp = LIST_NEXT(clp, lc_hash);
            }
            i++;
        }
        if (cnt < maxcnt)
            dumpp[cnt].ndcl_clid.nclid_idlen = 0;
        NFSUNLOCKSTATE();
        NFSLOCKV4ROOTMUTEX();
        nfsv4_relref(&nfsv4rootfs_lock);
        NFSUNLOCKV4ROOTMUTEX();
}

/*
 * Dump stats for a client. Must be called with the NFSSTATELOCK and spl'd.
 */
static void
nfsrv_dumpaclient(struct nfsclient *clp, struct nfsd_dumpclients *dumpp)
{
        struct nfsstate *stp, *openstp, *lckownstp;
        struct nfslock *lop;
        struct sockaddr *sad;
        struct sockaddr_in *rad;
        struct sockaddr_in6 *rad6;

        dumpp->ndcl_nopenowners = dumpp->ndcl_nlockowners = 0;
        dumpp->ndcl_nopens = dumpp->ndcl_nlocks = 0;
        dumpp->ndcl_ndelegs = dumpp->ndcl_nolddelegs = 0;
        dumpp->ndcl_flags = clp->lc_flags;
        dumpp->ndcl_clid.nclid_idlen = clp->lc_idlen;
        NFSBCOPY(clp->lc_id, dumpp->ndcl_clid.nclid_id, clp->lc_idlen);
        sad = NFSSOCKADDR(clp->lc_req.nr_nam, struct sockaddr *);
        dumpp->ndcl_addrfam = sad->sa_family;
        if (sad->sa_family == AF_INET) {
                rad = (struct sockaddr_in *)sad;
                dumpp->ndcl_cbaddr.sin_addr = rad->sin_addr;
        } else {
                rad6 = (struct sockaddr_in6 *)sad;
                dumpp->ndcl_cbaddr.sin6_addr = rad6->sin6_addr;
        }

        /*
         * Now, scan the state lists and total up the opens and locks.
         */
        LIST_FOREACH(stp, &clp->lc_open, ls_list) {
            dumpp->ndcl_nopenowners++;
            LIST_FOREACH(openstp, &stp->ls_open, ls_list) {
                dumpp->ndcl_nopens++;
                LIST_FOREACH(lckownstp, &openstp->ls_open, ls_list) {
                    dumpp->ndcl_nlockowners++;
                    LIST_FOREACH(lop, &lckownstp->ls_lock, lo_lckowner) {
                        dumpp->ndcl_nlocks++;
                    }
                }
            }
        }

        /*
         * and the delegation lists.
         */
        LIST_FOREACH(stp, &clp->lc_deleg, ls_list) {
            dumpp->ndcl_ndelegs++;
        }
        LIST_FOREACH(stp, &clp->lc_olddeleg, ls_list) {
            dumpp->ndcl_nolddelegs++;
        }
}

/*
 * Dump out lock stats for a file.
 */
APPLESTATIC void
nfsrv_dumplocks(vnode_t vp, struct nfsd_dumplocks *ldumpp, int maxcnt,
    NFSPROC_T *p)
{
        struct nfsstate *stp;
        struct nfslock *lop;
        int cnt = 0;
        struct nfslockfile *lfp;
        struct sockaddr *sad;
        struct sockaddr_in *rad;
        struct sockaddr_in6 *rad6;
        int ret;
        fhandle_t nfh;

        ret = nfsrv_getlockfh(vp, 0, NULL, &nfh, p);
        /*
         * First, get a reference on the nfsv4rootfs_lock so that an
         * exclusive lock on it cannot be acquired while dumping the locks.
         */
        NFSLOCKV4ROOTMUTEX();
        nfsv4_getref(&nfsv4rootfs_lock, NULL, NFSV4ROOTLOCKMUTEXPTR, NULL);
        NFSUNLOCKV4ROOTMUTEX();
        NFSLOCKSTATE();
        if (!ret)
                ret = nfsrv_getlockfile(0, NULL, &lfp, &nfh, 0);
        if (ret) {
                ldumpp[0].ndlck_clid.nclid_idlen = 0;
                NFSUNLOCKSTATE();
                NFSLOCKV4ROOTMUTEX();
                nfsv4_relref(&nfsv4rootfs_lock);
                NFSUNLOCKV4ROOTMUTEX();
                return;
        }

        /*
         * For each open share on file, dump it out.
         */
        stp = LIST_FIRST(&lfp->lf_open);
        while (stp != NULL && cnt < maxcnt) {
                ldumpp[cnt].ndlck_flags = stp->ls_flags;
                ldumpp[cnt].ndlck_stateid.seqid = stp->ls_stateid.seqid;
                ldumpp[cnt].ndlck_stateid.other[0] = stp->ls_stateid.other[0];
                ldumpp[cnt].ndlck_stateid.other[1] = stp->ls_stateid.other[1];
                ldumpp[cnt].ndlck_stateid.other[2] = stp->ls_stateid.other[2];
                ldumpp[cnt].ndlck_owner.nclid_idlen =
                    stp->ls_openowner->ls_ownerlen;
                NFSBCOPY(stp->ls_openowner->ls_owner,
                    ldumpp[cnt].ndlck_owner.nclid_id,
                    stp->ls_openowner->ls_ownerlen);
                ldumpp[cnt].ndlck_clid.nclid_idlen = stp->ls_clp->lc_idlen;
                NFSBCOPY(stp->ls_clp->lc_id, ldumpp[cnt].ndlck_clid.nclid_id,
                    stp->ls_clp->lc_idlen);
                sad=NFSSOCKADDR(stp->ls_clp->lc_req.nr_nam, struct sockaddr *);
                ldumpp[cnt].ndlck_addrfam = sad->sa_family;
                if (sad->sa_family == AF_INET) {
                        rad = (struct sockaddr_in *)sad;
                        ldumpp[cnt].ndlck_cbaddr.sin_addr = rad->sin_addr;
                } else {
                        rad6 = (struct sockaddr_in6 *)sad;
                        ldumpp[cnt].ndlck_cbaddr.sin6_addr = rad6->sin6_addr;
                }
                stp = LIST_NEXT(stp, ls_file);
                cnt++;
        }

        /*
         * and all locks.
         */
        lop = LIST_FIRST(&lfp->lf_lock);
        while (lop != NULL && cnt < maxcnt) {
                stp = lop->lo_stp;
                ldumpp[cnt].ndlck_flags = lop->lo_flags;
                ldumpp[cnt].ndlck_first = lop->lo_first;
                ldumpp[cnt].ndlck_end = lop->lo_end;
                ldumpp[cnt].ndlck_stateid.seqid = stp->ls_stateid.seqid;
                ldumpp[cnt].ndlck_stateid.other[0] = stp->ls_stateid.other[0];
                ldumpp[cnt].ndlck_stateid.other[1] = stp->ls_stateid.other[1];
                ldumpp[cnt].ndlck_stateid.other[2] = stp->ls_stateid.other[2];
                ldumpp[cnt].ndlck_owner.nclid_idlen = stp->ls_ownerlen;
                NFSBCOPY(stp->ls_owner, ldumpp[cnt].ndlck_owner.nclid_id,
                    stp->ls_ownerlen);
                ldumpp[cnt].ndlck_clid.nclid_idlen = stp->ls_clp->lc_idlen;
                NFSBCOPY(stp->ls_clp->lc_id, ldumpp[cnt].ndlck_clid.nclid_id,
                    stp->ls_clp->lc_idlen);
                sad=NFSSOCKADDR(stp->ls_clp->lc_req.nr_nam, struct sockaddr *);
                ldumpp[cnt].ndlck_addrfam = sad->sa_family;
                if (sad->sa_family == AF_INET) {
                        rad = (struct sockaddr_in *)sad;
                        ldumpp[cnt].ndlck_cbaddr.sin_addr = rad->sin_addr;
                } else {
                        rad6 = (struct sockaddr_in6 *)sad;
                        ldumpp[cnt].ndlck_cbaddr.sin6_addr = rad6->sin6_addr;
                }
                lop = LIST_NEXT(lop, lo_lckfile);
                cnt++;
        }

        /*
         * and the delegations.
         */
        stp = LIST_FIRST(&lfp->lf_deleg);
        while (stp != NULL && cnt < maxcnt) {
                ldumpp[cnt].ndlck_flags = stp->ls_flags;
                ldumpp[cnt].ndlck_stateid.seqid = stp->ls_stateid.seqid;
                ldumpp[cnt].ndlck_stateid.other[0] = stp->ls_stateid.other[0];
                ldumpp[cnt].ndlck_stateid.other[1] = stp->ls_stateid.other[1];
                ldumpp[cnt].ndlck_stateid.other[2] = stp->ls_stateid.other[2];
                ldumpp[cnt].ndlck_owner.nclid_idlen = 0;
                ldumpp[cnt].ndlck_clid.nclid_idlen = stp->ls_clp->lc_idlen;
                NFSBCOPY(stp->ls_clp->lc_id, ldumpp[cnt].ndlck_clid.nclid_id,
                    stp->ls_clp->lc_idlen);
                sad=NFSSOCKADDR(stp->ls_clp->lc_req.nr_nam, struct sockaddr *);
                ldumpp[cnt].ndlck_addrfam = sad->sa_family;
                if (sad->sa_family == AF_INET) {
                        rad = (struct sockaddr_in *)sad;
                        ldumpp[cnt].ndlck_cbaddr.sin_addr = rad->sin_addr;
                } else {
                        rad6 = (struct sockaddr_in6 *)sad;
                        ldumpp[cnt].ndlck_cbaddr.sin6_addr = rad6->sin6_addr;
                }
                stp = LIST_NEXT(stp, ls_file);
                cnt++;
        }

        /*
         * If list isn't full, mark end of list by setting the client name
         * to zero length.
         */
        if (cnt < maxcnt)
                ldumpp[cnt].ndlck_clid.nclid_idlen = 0;
        NFSUNLOCKSTATE();
        NFSLOCKV4ROOTMUTEX();
        nfsv4_relref(&nfsv4rootfs_lock);
        NFSUNLOCKV4ROOTMUTEX();
}

/*
 * Server timer routine. It can scan any linked list, so long
 * as it holds the spin/mutex lock and there is no exclusive lock on
 * nfsv4rootfs_lock.
 * (For OpenBSD, a kthread is ok. For FreeBSD, I think it is ok
 *  to do this from a callout, since the spin locks work. For
 *  Darwin, I'm not sure what will work correctly yet.)
 * Should be called once per second.
 */
APPLESTATIC void
nfsrv_servertimer(void)
{
        struct nfsclient *clp, *nclp;
        struct nfsstate *stp, *nstp;
        int got_ref, i;

        /*
         * Make sure nfsboottime is set. This is used by V3 as well
         * as V4. Note that nfsboottime is not nfsrvboottime, which is
         * only used by the V4 server for leases.
         */
        if (nfsboottime.tv_sec == 0)
                NFSSETBOOTTIME(nfsboottime);

        /*
         * If server hasn't started yet, just return.
         */
        NFSLOCKSTATE();
        if (nfsrv_stablefirst.nsf_eograce == 0) {
                NFSUNLOCKSTATE();
                return;
        }
        if (!(nfsrv_stablefirst.nsf_flags & NFSNSF_UPDATEDONE)) {
                if (!(nfsrv_stablefirst.nsf_flags & NFSNSF_GRACEOVER) &&
                    NFSD_MONOSEC > nfsrv_stablefirst.nsf_eograce)
                        nfsrv_stablefirst.nsf_flags |=
                            (NFSNSF_GRACEOVER | NFSNSF_NEEDLOCK);
                NFSUNLOCKSTATE();
                return;
        }

        /*
         * Try and get a reference count on the nfsv4rootfs_lock so that
         * no nfsd thread can acquire an exclusive lock on it before this
         * call is done. If it is already exclusively locked, just return.
         */
        NFSLOCKV4ROOTMUTEX();
        got_ref = nfsv4_getref_nonblock(&nfsv4rootfs_lock);
        NFSUNLOCKV4ROOTMUTEX();
        if (got_ref == 0) {
                NFSUNLOCKSTATE();
                return;
        }

        /*
         * For each client...
         */
        for (i = 0; i < nfsrv_clienthashsize; i++) {
            clp = LIST_FIRST(&nfsclienthash[i]);
            while (clp != NULL) {
                nclp = LIST_NEXT(clp, lc_hash);
                if (!(clp->lc_flags & LCL_EXPIREIT)) {
                    if (((clp->lc_expiry + NFSRV_STALELEASE) < NFSD_MONOSEC
                         && ((LIST_EMPTY(&clp->lc_deleg)
                              && LIST_EMPTY(&clp->lc_open)) ||
                             nfsrv_clients > nfsrv_clienthighwater)) ||
                        (clp->lc_expiry + NFSRV_MOULDYLEASE) < NFSD_MONOSEC ||
                        (clp->lc_expiry < NFSD_MONOSEC &&
                         (nfsrv_openpluslock * 10 / 9) > nfsrv_v4statelimit)) {
                        /*
                         * Lease has expired several nfsrv_lease times ago:
                         * PLUS
                         *    - no state is associated with it
                         *    OR
                         *    - above high water mark for number of clients
                         *      (nfsrv_clienthighwater should be large enough
                         *       that this only occurs when clients fail to
                         *       use the same nfs_client_id4.id. Maybe somewhat
                         *       higher that the maximum number of clients that
                         *       will mount this server?)
                         * OR
                         * Lease has expired a very long time ago
                         * OR
                         * Lease has expired PLUS the number of opens + locks
                         * has exceeded 90% of capacity
                         *
                         * --> Mark for expiry. The actual expiry will be done
                         *     by an nfsd sometime soon.
                         */
                        clp->lc_flags |= LCL_EXPIREIT;
                        nfsrv_stablefirst.nsf_flags |=
                            (NFSNSF_NEEDLOCK | NFSNSF_EXPIREDCLIENT);
                    } else {
                        /*
                         * If there are no opens, increment no open tick cnt
                         * If time exceeds NFSNOOPEN, mark it to be thrown away
                         * otherwise, if there is an open, reset no open time
                         * Hopefully, this will avoid excessive re-creation
                         * of open owners and subsequent open confirms.
                         */
                        stp = LIST_FIRST(&clp->lc_open);
                        while (stp != NULL) {
                                nstp = LIST_NEXT(stp, ls_list);
                                if (LIST_EMPTY(&stp->ls_open)) {
                                        stp->ls_noopens++;
                                        if (stp->ls_noopens > NFSNOOPEN ||
                                            (nfsrv_openpluslock * 2) >
                                            nfsrv_v4statelimit)
                                                nfsrv_stablefirst.nsf_flags |=
                                                        NFSNSF_NOOPENS;
                                } else {
                                        stp->ls_noopens = 0;
                                }
                                stp = nstp;
                        }
                    }
                }
                clp = nclp;
            }
        }
        NFSUNLOCKSTATE();
        NFSLOCKV4ROOTMUTEX();
        nfsv4_relref(&nfsv4rootfs_lock);
        NFSUNLOCKV4ROOTMUTEX();
}

/*
 * The following set of functions free up the various data structures.
 */
/*
 * Clear out all open/lock state related to this nfsclient.
 * Caller must hold an exclusive lock on nfsv4rootfs_lock, so that
 * there are no other active nfsd threads.
 */
APPLESTATIC void
nfsrv_cleanclient(struct nfsclient *clp, NFSPROC_T *p)
{
        struct nfsstate *stp, *nstp;
        struct nfsdsession *sep, *nsep;

        LIST_FOREACH_SAFE(stp, &clp->lc_open, ls_list, nstp)
                nfsrv_freeopenowner(stp, 1, p);
        if ((clp->lc_flags & LCL_ADMINREVOKED) == 0)
                LIST_FOREACH_SAFE(sep, &clp->lc_session, sess_list, nsep)
                        (void)nfsrv_freesession(sep, NULL);
}

/*
 * Free a client that has been cleaned. It should also already have been
 * removed from the lists.
 * (Just to be safe w.r.t. newnfs_disconnect(), call this function when
 *  softclock interrupts are enabled.)
 */
APPLESTATIC void
nfsrv_zapclient(struct nfsclient *clp, NFSPROC_T *p)
{

#ifdef notyet
        if ((clp->lc_flags & (LCL_GSS | LCL_CALLBACKSON)) ==
             (LCL_GSS | LCL_CALLBACKSON) &&
            (clp->lc_hand.nfsh_flag & NFSG_COMPLETE) &&
            clp->lc_handlelen > 0) {
                clp->lc_hand.nfsh_flag &= ~NFSG_COMPLETE;
                clp->lc_hand.nfsh_flag |= NFSG_DESTROYED;
                (void) nfsrv_docallback(clp, NFSV4PROC_CBNULL,
                        NULL, 0, NULL, NULL, NULL, p);
        }
#endif
        newnfs_disconnect(&clp->lc_req);
        NFSSOCKADDRFREE(clp->lc_req.nr_nam);
        NFSFREEMUTEX(&clp->lc_req.nr_mtx);
        free(clp->lc_stateid, M_NFSDCLIENT);
        free(clp, M_NFSDCLIENT);
        NFSLOCKSTATE();
        nfsstatsv1.srvclients--;
        nfsrv_openpluslock--;
        nfsrv_clients--;
        NFSUNLOCKSTATE();
}

/*
 * Free a list of delegation state structures.
 * (This function will also free all nfslockfile structures that no
 *  longer have associated state.)
 */
APPLESTATIC void
nfsrv_freedeleglist(struct nfsstatehead *sthp)
{
        struct nfsstate *stp, *nstp;

        LIST_FOREACH_SAFE(stp, sthp, ls_list, nstp) {
                nfsrv_freedeleg(stp);
        }
        LIST_INIT(sthp);
}

/*
 * Free up a delegation.
 */
static void
nfsrv_freedeleg(struct nfsstate *stp)
{
        struct nfslockfile *lfp;

        LIST_REMOVE(stp, ls_hash);
        LIST_REMOVE(stp, ls_list);
        LIST_REMOVE(stp, ls_file);
        lfp = stp->ls_lfp;
        if (LIST_EMPTY(&lfp->lf_open) &&
            LIST_EMPTY(&lfp->lf_lock) && LIST_EMPTY(&lfp->lf_deleg) &&
            LIST_EMPTY(&lfp->lf_locallock) && LIST_EMPTY(&lfp->lf_rollback) &&
            lfp->lf_usecount == 0 &&
            nfsv4_testlock(&lfp->lf_locallock_lck) == 0)
                nfsrv_freenfslockfile(lfp);
        FREE((caddr_t)stp, M_NFSDSTATE);
        nfsstatsv1.srvdelegates--;
        nfsrv_openpluslock--;
        nfsrv_delegatecnt--;
}

/*
 * This function frees an open owner and all associated opens.
 */
static void
nfsrv_freeopenowner(struct nfsstate *stp, int cansleep, NFSPROC_T *p)
{
        struct nfsstate *nstp, *tstp;

        LIST_REMOVE(stp, ls_list);
        /*
         * Now, free all associated opens.
         */
        nstp = LIST_FIRST(&stp->ls_open);
        while (nstp != NULL) {
                tstp = nstp;
                nstp = LIST_NEXT(nstp, ls_list);
                (void) nfsrv_freeopen(tstp, NULL, cansleep, p);
        }
        if (stp->ls_op)
                nfsrvd_derefcache(stp->ls_op);
        FREE((caddr_t)stp, M_NFSDSTATE);
        nfsstatsv1.srvopenowners--;
        nfsrv_openpluslock--;
}

/*
 * This function frees an open (nfsstate open structure) with all associated
 * lock_owners and locks. It also frees the nfslockfile structure iff there
 * are no other opens on the file.
 * Returns 1 if it free'd the nfslockfile, 0 otherwise.
 */
static int
nfsrv_freeopen(struct nfsstate *stp, vnode_t vp, int cansleep, NFSPROC_T *p)
{
        struct nfsstate *nstp, *tstp;
        struct nfslockfile *lfp;
        int ret;

        LIST_REMOVE(stp, ls_hash);
        LIST_REMOVE(stp, ls_list);
        LIST_REMOVE(stp, ls_file);

        lfp = stp->ls_lfp;
        /*
         * Now, free all lockowners associated with this open.
         */
        LIST_FOREACH_SAFE(tstp, &stp->ls_open, ls_list, nstp)
                nfsrv_freelockowner(tstp, vp, cansleep, p);

        /*
         * The nfslockfile is freed here if there are no locks
         * associated with the open.
         * If there are locks associated with the open, the
         * nfslockfile structure can be freed via nfsrv_freelockowner().
         * Acquire the state mutex to avoid races with calls to
         * nfsrv_getlockfile().
         */
        if (cansleep != 0)
                NFSLOCKSTATE();
        if (lfp != NULL && LIST_EMPTY(&lfp->lf_open) &&
            LIST_EMPTY(&lfp->lf_deleg) && LIST_EMPTY(&lfp->lf_lock) &&
            LIST_EMPTY(&lfp->lf_locallock) && LIST_EMPTY(&lfp->lf_rollback) &&
            lfp->lf_usecount == 0 &&
            (cansleep != 0 || nfsv4_testlock(&lfp->lf_locallock_lck) == 0)) {
                nfsrv_freenfslockfile(lfp);
                ret = 1;
        } else
                ret = 0;
        if (cansleep != 0)
                NFSUNLOCKSTATE();
        FREE((caddr_t)stp, M_NFSDSTATE);
        nfsstatsv1.srvopens--;
        nfsrv_openpluslock--;
        return (ret);
}

/*
 * Frees a lockowner and all associated locks.
 */
static void
nfsrv_freelockowner(struct nfsstate *stp, vnode_t vp, int cansleep,
    NFSPROC_T *p)
{

        LIST_REMOVE(stp, ls_hash);
        LIST_REMOVE(stp, ls_list);
        nfsrv_freeallnfslocks(stp, vp, cansleep, p);
        if (stp->ls_op)
                nfsrvd_derefcache(stp->ls_op);
        FREE((caddr_t)stp, M_NFSDSTATE);
        nfsstatsv1.srvlockowners--;
        nfsrv_openpluslock--;
}

/*
 * Free all the nfs locks on a lockowner.
 */
static void
nfsrv_freeallnfslocks(struct nfsstate *stp, vnode_t vp, int cansleep,
    NFSPROC_T *p)
{
        struct nfslock *lop, *nlop;
        struct nfsrollback *rlp, *nrlp;
        struct nfslockfile *lfp = NULL;
        int gottvp = 0;
        vnode_t tvp = NULL;
        uint64_t first, end;

        if (vp != NULL)
                ASSERT_VOP_UNLOCKED(vp, "nfsrv_freeallnfslocks: vnode locked");
        lop = LIST_FIRST(&stp->ls_lock);
        while (lop != NULL) {
                nlop = LIST_NEXT(lop, lo_lckowner);
                /*
                 * Since all locks should be for the same file, lfp should
                 * not change.
                 */
                if (lfp == NULL)
                        lfp = lop->lo_lfp;
                else if (lfp != lop->lo_lfp)
                        panic("allnfslocks");
                /*
                 * If vp is NULL and cansleep != 0, a vnode must be acquired
                 * from the file handle. This only occurs when called from
                 * nfsrv_cleanclient().
                 */
                if (gottvp == 0) {
                        if (nfsrv_dolocallocks == 0)
                                tvp = NULL;
                        else if (vp == NULL && cansleep != 0) {
                                tvp = nfsvno_getvp(&lfp->lf_fh);
                                NFSVOPUNLOCK(tvp, 0);
                        } else
                                tvp = vp;
                        gottvp = 1;
                }

                if (tvp != NULL) {
                        if (cansleep == 0)
                                panic("allnfs2");
                        first = lop->lo_first;
                        end = lop->lo_end;
                        nfsrv_freenfslock(lop);
                        nfsrv_localunlock(tvp, lfp, first, end, p);
                        LIST_FOREACH_SAFE(rlp, &lfp->lf_rollback, rlck_list,
                            nrlp)
                                free(rlp, M_NFSDROLLBACK);
                        LIST_INIT(&lfp->lf_rollback);
                } else
                        nfsrv_freenfslock(lop);
                lop = nlop;
        }
        if (vp == NULL && tvp != NULL)
                vrele(tvp);
}

/*
 * Free an nfslock structure.
 */
static void
nfsrv_freenfslock(struct nfslock *lop)
{

        if (lop->lo_lckfile.le_prev != NULL) {
                LIST_REMOVE(lop, lo_lckfile);
                nfsstatsv1.srvlocks--;
                nfsrv_openpluslock--;
        }
        LIST_REMOVE(lop, lo_lckowner);
        FREE((caddr_t)lop, M_NFSDLOCK);
}

/*
 * This function frees an nfslockfile structure.
 */
static void
nfsrv_freenfslockfile(struct nfslockfile *lfp)
{

        LIST_REMOVE(lfp, lf_hash);
        FREE((caddr_t)lfp, M_NFSDLOCKFILE);
}

/*
 * This function looks up an nfsstate structure via stateid.
 */
static int
nfsrv_getstate(struct nfsclient *clp, nfsv4stateid_t *stateidp, __unused u_int32_t flags,
    struct nfsstate **stpp)
{
        struct nfsstate *stp;
        struct nfsstatehead *hp;
        int error = 0;

        *stpp = NULL;
        hp = NFSSTATEHASH(clp, *stateidp);
        LIST_FOREACH(stp, hp, ls_hash) {
                if (!NFSBCMP(stp->ls_stateid.other, stateidp->other,
                        NFSX_STATEIDOTHER))
                        break;
        }

        /*
         * If no state id in list, return NFSERR_BADSTATEID.
         */
        if (stp == NULL) {
                error = NFSERR_BADSTATEID;
                goto out;
        }
        *stpp = stp;

out:
        NFSEXITCODE(error);
        return (error);
}

/*
 * This function gets an nfsstate structure via owner string.
 */
static void
nfsrv_getowner(struct nfsstatehead *hp, struct nfsstate *new_stp,
    struct nfsstate **stpp)
{
        struct nfsstate *stp;

        *stpp = NULL;
        LIST_FOREACH(stp, hp, ls_list) {
                if (new_stp->ls_ownerlen == stp->ls_ownerlen &&
                  !NFSBCMP(new_stp->ls_owner,stp->ls_owner,stp->ls_ownerlen)) {
                        *stpp = stp;
                        return;
                }
        }
}

/*
 * Lock control function called to update lock status.
 * Returns 0 upon success, -1 if there is no lock and the flags indicate
 * that one isn't to be created and an NFSERR_xxx for other errors.
 * The structures new_stp and new_lop are passed in as pointers that should
 * be set to NULL if the structure is used and shouldn't be free'd.
 * For the NFSLCK_TEST and NFSLCK_CHECK cases, the structures are
 * never used and can safely be allocated on the stack. For all other
 * cases, *new_stpp and *new_lopp should be malloc'd before the call,
 * in case they are used.
 */
APPLESTATIC int
nfsrv_lockctrl(vnode_t vp, struct nfsstate **new_stpp,
    struct nfslock **new_lopp, struct nfslockconflict *cfp,
    nfsquad_t clientid, nfsv4stateid_t *stateidp,
    __unused struct nfsexstuff *exp,
    struct nfsrv_descript *nd, NFSPROC_T *p)
{
        struct nfslock *lop;
        struct nfsstate *new_stp = *new_stpp;
        struct nfslock *new_lop = *new_lopp;
        struct nfsstate *tstp, *mystp, *nstp;
        int specialid = 0;
        struct nfslockfile *lfp;
        struct nfslock *other_lop = NULL;
        struct nfsstate *stp, *lckstp = NULL;
        struct nfsclient *clp = NULL;
        u_int32_t bits;
        int error = 0, haslock = 0, ret, reterr;
        int getlckret, delegation = 0, filestruct_locked, vnode_unlocked = 0;
        fhandle_t nfh;
        uint64_t first, end;
        uint32_t lock_flags;

        if (new_stp->ls_flags & (NFSLCK_CHECK | NFSLCK_SETATTR)) {
                /*
                 * Note the special cases of "all 1s" or "all 0s" stateids and
                 * let reads with all 1s go ahead.
                 */
                if (new_stp->ls_stateid.seqid == 0x0 &&
                    new_stp->ls_stateid.other[0] == 0x0 &&
                    new_stp->ls_stateid.other[1] == 0x0 &&
                    new_stp->ls_stateid.other[2] == 0x0)
                        specialid = 1;
                else if (new_stp->ls_stateid.seqid == 0xffffffff &&
                    new_stp->ls_stateid.other[0] == 0xffffffff &&
                    new_stp->ls_stateid.other[1] == 0xffffffff &&
                    new_stp->ls_stateid.other[2] == 0xffffffff)
                        specialid = 2;
        }

        /*
         * Check for restart conditions (client and server).
         */
        error = nfsrv_checkrestart(clientid, new_stp->ls_flags,
            &new_stp->ls_stateid, specialid);
        if (error)
                goto out;

        /*
         * Check for state resource limit exceeded.
         */
        if ((new_stp->ls_flags & NFSLCK_LOCK) &&
            nfsrv_openpluslock > nfsrv_v4statelimit) {
                error = NFSERR_RESOURCE;
                goto out;
        }

        /*
         * For the lock case, get another nfslock structure,
         * just in case we need it.
         * Malloc now, before we start sifting through the linked lists,
         * in case we have to wait for memory.
         */
tryagain:
        if (new_stp->ls_flags & NFSLCK_LOCK)
                MALLOC(other_lop, struct nfslock *, sizeof (struct nfslock),
                    M_NFSDLOCK, M_WAITOK);
        filestruct_locked = 0;
        reterr = 0;
        lfp = NULL;

        /*
         * Get the lockfile structure for CFH now, so we can do a sanity
         * check against the stateid, before incrementing the seqid#, since
         * we want to return NFSERR_BADSTATEID on failure and the seqid#
         * shouldn't be incremented for this case.
         * If nfsrv_getlockfile() returns -1, it means "not found", which
         * will be handled later.
         * If we are doing Lock/LockU and local locking is enabled, sleep
         * lock the nfslockfile structure.
         */
        getlckret = nfsrv_getlockfh(vp, new_stp->ls_flags, NULL, &nfh, p);
        NFSLOCKSTATE();
        if (getlckret == 0) {
                if ((new_stp->ls_flags & (NFSLCK_LOCK | NFSLCK_UNLOCK)) != 0 &&
                    nfsrv_dolocallocks != 0 && nd->nd_repstat == 0) {
                        getlckret = nfsrv_getlockfile(new_stp->ls_flags, NULL,
                            &lfp, &nfh, 1);
                        if (getlckret == 0)
                                filestruct_locked = 1;
                } else
                        getlckret = nfsrv_getlockfile(new_stp->ls_flags, NULL,
                            &lfp, &nfh, 0);
        }
        if (getlckret != 0 && getlckret != -1)
                reterr = getlckret;

        if (filestruct_locked != 0) {
                LIST_INIT(&lfp->lf_rollback);
                if ((new_stp->ls_flags & NFSLCK_LOCK)) {
                        /*
                         * For local locking, do the advisory locking now, so
                         * that any conflict can be detected. A failure later
                         * can be rolled back locally. If an error is returned,
                         * struct nfslockfile has been unlocked and any local
                         * locking rolled back.
                         */
                        NFSUNLOCKSTATE();
                        if (vnode_unlocked == 0) {
                                ASSERT_VOP_ELOCKED(vp, "nfsrv_lockctrl1");
                                vnode_unlocked = 1;
                                NFSVOPUNLOCK(vp, 0);
                        }
                        reterr = nfsrv_locallock(vp, lfp,
                            (new_lop->lo_flags & (NFSLCK_READ | NFSLCK_WRITE)),
                            new_lop->lo_first, new_lop->lo_end, cfp, p);
                        NFSLOCKSTATE();
                }
        }

        if (specialid == 0) {
            if (new_stp->ls_flags & NFSLCK_TEST) {
                /*
                 * RFC 3530 does not list LockT as an op that renews a
                 * lease, but the consensus seems to be that it is ok
                 * for a server to do so.
                 */
                error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp, NULL,
                    (nfsquad_t)((u_quad_t)0), 0, nd, p);

                /*
                 * Since NFSERR_EXPIRED, NFSERR_ADMINREVOKED are not valid
                 * error returns for LockT, just go ahead and test for a lock,
                 * since there are no locks for this client, but other locks
                 * can conflict. (ie. same client will always be false)
                 */
                if (error == NFSERR_EXPIRED || error == NFSERR_ADMINREVOKED)
                    error = 0;
                lckstp = new_stp;
            } else {
              error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp, NULL,
                (nfsquad_t)((u_quad_t)0), 0, nd, p);
              if (error == 0)
                /*
                 * Look up the stateid
                 */
                error = nfsrv_getstate(clp, &new_stp->ls_stateid,
                  new_stp->ls_flags, &stp);
              /*
               * do some sanity checks for an unconfirmed open or a
               * stateid that refers to the wrong file, for an open stateid
               */
              if (error == 0 && (stp->ls_flags & NFSLCK_OPEN) &&
                  ((stp->ls_openowner->ls_flags & NFSLCK_NEEDSCONFIRM) ||
                   (getlckret == 0 && stp->ls_lfp != lfp))){
                      /*
                       * NFSLCK_SETATTR should return OK rather than NFSERR_BADSTATEID
                       * The only exception is using SETATTR with SIZE.
                       * */
                    if ((new_stp->ls_flags &
                         (NFSLCK_SETATTR | NFSLCK_CHECK)) != NFSLCK_SETATTR)
                             error = NFSERR_BADSTATEID;
              }
              
                if (error == 0 &&
                  (stp->ls_flags & (NFSLCK_DELEGREAD | NFSLCK_DELEGWRITE)) &&
                  getlckret == 0 && stp->ls_lfp != lfp)
                        error = NFSERR_BADSTATEID;

              /*
               * If the lockowner stateid doesn't refer to the same file,
               * I believe that is considered ok, since some clients will
               * only create a single lockowner and use that for all locks
               * on all files.
               * For now, log it as a diagnostic, instead of considering it
               * a BadStateid.
               */
              if (error == 0 && (stp->ls_flags &
                  (NFSLCK_OPEN | NFSLCK_DELEGREAD | NFSLCK_DELEGWRITE)) == 0 &&
                  getlckret == 0 && stp->ls_lfp != lfp) {
#ifdef DIAGNOSTIC
                  printf("Got a lock statid for different file open\n");
#endif
                  /*
                  error = NFSERR_BADSTATEID;
                  */
              }

              if (error == 0) {
                    if (new_stp->ls_flags & NFSLCK_OPENTOLOCK) {
                        /*
                         * If haslock set, we've already checked the seqid.
                         */
                        if (!haslock) {
                            if (stp->ls_flags & NFSLCK_OPEN)
                                error = nfsrv_checkseqid(nd, new_stp->ls_seq,
                                    stp->ls_openowner, new_stp->ls_op);
                            else
                                error = NFSERR_BADSTATEID;
                        }
                        if (!error)
                            nfsrv_getowner(&stp->ls_open, new_stp, &lckstp);
                        if (lckstp)
                            /*
                             * I believe this should be an error, but it
                             * isn't obvious what NFSERR_xxx would be
                             * appropriate, so I'll use NFSERR_INVAL for now.
                             */
                            error = NFSERR_INVAL;
                        else
                            lckstp = new_stp;
                    } else if (new_stp->ls_flags&(NFSLCK_LOCK|NFSLCK_UNLOCK)) {
                        /*
                         * If haslock set, ditto above.
                         */
                        if (!haslock) {
                            if (stp->ls_flags & NFSLCK_OPEN)
                                error = NFSERR_BADSTATEID;
                            else
                                error = nfsrv_checkseqid(nd, new_stp->ls_seq,
                                    stp, new_stp->ls_op);
                        }
                        lckstp = stp;
                    } else {
                        lckstp = stp;
                    }
              }
              /*
               * If the seqid part of the stateid isn't the same, return
               * NFSERR_OLDSTATEID for cases other than I/O Ops.
               * For I/O Ops, only return NFSERR_OLDSTATEID if
               * nfsrv_returnoldstateid is set. (The consensus on the email
               * list was that most clients would prefer to not receive
               * NFSERR_OLDSTATEID for I/O Ops, but the RFC suggests that that
               * is what will happen, so I use the nfsrv_returnoldstateid to
               * allow for either server configuration.)
               */
              if (!error && stp->ls_stateid.seqid!=new_stp->ls_stateid.seqid &&
                  (((nd->nd_flag & ND_NFSV41) == 0 &&
                   (!(new_stp->ls_flags & NFSLCK_CHECK) ||
                    nfsrv_returnoldstateid)) ||
                   ((nd->nd_flag & ND_NFSV41) != 0 &&
                    new_stp->ls_stateid.seqid != 0)))
                    error = NFSERR_OLDSTATEID;
            }
        }

        /*
         * Now we can check for grace.
         */
        if (!error)
                error = nfsrv_checkgrace(nd, clp, new_stp->ls_flags);
        if ((new_stp->ls_flags & NFSLCK_RECLAIM) && !error &&
                nfsrv_checkstable(clp))
                error = NFSERR_NOGRACE;
        /*
         * If we successfully Reclaimed state, note that.
         */
        if ((new_stp->ls_flags & NFSLCK_RECLAIM) && !error)
                nfsrv_markstable(clp);

        /*
         * At this point, either error == NFSERR_BADSTATEID or the
         * seqid# has been updated, so we can return any error.
         * If error == 0, there may be an error in:
         *    nd_repstat - Set by the calling function.
         *    reterr - Set above, if getting the nfslockfile structure
         *       or acquiring the local lock failed.
         *    (If both of these are set, nd_repstat should probably be
         *     returned, since that error was detected before this
         *     function call.)
         */
        if (error != 0 || nd->nd_repstat != 0 || reterr != 0) {
                if (error == 0) {
                        if (nd->nd_repstat != 0)
                                error = nd->nd_repstat;
                        else
                                error = reterr;
                }
                if (filestruct_locked != 0) {
                        /* Roll back local locks. */
                        NFSUNLOCKSTATE();
                        if (vnode_unlocked == 0) {
                                ASSERT_VOP_ELOCKED(vp, "nfsrv_lockctrl2");
                                vnode_unlocked = 1;
                                NFSVOPUNLOCK(vp, 0);
                        }
                        nfsrv_locallock_rollback(vp, lfp, p);
                        NFSLOCKSTATE();
                        nfsrv_unlocklf(lfp);
                }
                NFSUNLOCKSTATE();
                goto out;
        }

        /*
         * Check the nfsrv_getlockfile return.
         * Returned -1 if no structure found.
         */
        if (getlckret == -1) {
                error = NFSERR_EXPIRED;
                /*
                 * Called from lockt, so no lock is OK.
                 */
                if (new_stp->ls_flags & NFSLCK_TEST) {
                        error = 0;
                } else if (new_stp->ls_flags &
                    (NFSLCK_CHECK | NFSLCK_SETATTR)) {
                        /*
                         * Called to check for a lock, OK if the stateid is all
                         * 1s or all 0s, but there should be an nfsstate
                         * otherwise.
                         * (ie. If there is no open, I'll assume no share
                         *  deny bits.)
                         */
                        if (specialid)
                                error = 0;
                        else
                                error = NFSERR_BADSTATEID;
                }
                NFSUNLOCKSTATE();
                goto out;
        }

        /*
         * For NFSLCK_CHECK and NFSLCK_LOCK, test for a share conflict.
         * For NFSLCK_CHECK, allow a read if write access is granted,
         * but check for a deny. For NFSLCK_LOCK, require correct access,
         * which implies a conflicting deny can't exist.
         */
        if (new_stp->ls_flags & (NFSLCK_CHECK | NFSLCK_LOCK)) {
            /*
             * Four kinds of state id:
             * - specialid (all 0s or all 1s), only for NFSLCK_CHECK
             * - stateid for an open
             * - stateid for a delegation
             * - stateid for a lock owner
             */
            if (!specialid) {
                if (stp->ls_flags & (NFSLCK_DELEGREAD | NFSLCK_DELEGWRITE)) {
                    delegation = 1;
                    mystp = stp;
                    nfsrv_delaydelegtimeout(stp);
                } else if (stp->ls_flags & NFSLCK_OPEN) {
                    mystp = stp;
                } else {
                    mystp = stp->ls_openstp;
                }
                /*
                 * If locking or checking, require correct access
                 * bit set.
                 */
                if (((new_stp->ls_flags & NFSLCK_LOCK) &&
                     !((new_lop->lo_flags >> NFSLCK_LOCKSHIFT) &
                       mystp->ls_flags & NFSLCK_ACCESSBITS)) ||
                    ((new_stp->ls_flags & (NFSLCK_CHECK|NFSLCK_READACCESS)) ==
                      (NFSLCK_CHECK | NFSLCK_READACCESS) &&
                     !(mystp->ls_flags & NFSLCK_READACCESS)) ||
                    ((new_stp->ls_flags & (NFSLCK_CHECK|NFSLCK_WRITEACCESS)) ==
                      (NFSLCK_CHECK | NFSLCK_WRITEACCESS) &&
                     !(mystp->ls_flags & NFSLCK_WRITEACCESS))) {
                        if (filestruct_locked != 0) {
                                /* Roll back local locks. */
                                NFSUNLOCKSTATE();
                                if (vnode_unlocked == 0) {
                                        ASSERT_VOP_ELOCKED(vp,
                                            "nfsrv_lockctrl3");
                                        vnode_unlocked = 1;
                                        NFSVOPUNLOCK(vp, 0);
                                }
                                nfsrv_locallock_rollback(vp, lfp, p);
                                NFSLOCKSTATE();
                                nfsrv_unlocklf(lfp);
                        }
                        NFSUNLOCKSTATE();
                        error = NFSERR_OPENMODE;
                        goto out;
                }
            } else
                mystp = NULL;
            if ((new_stp->ls_flags & NFSLCK_CHECK) && !delegation) {
                /*
                 * Check for a conflicting deny bit.
                 */
                LIST_FOREACH(tstp, &lfp->lf_open, ls_file) {
                    if (tstp != mystp) {
                        bits = tstp->ls_flags;
                        bits >>= NFSLCK_SHIFT;
                        if (new_stp->ls_flags & bits & NFSLCK_ACCESSBITS) {
                            KASSERT(vnode_unlocked == 0,
                                ("nfsrv_lockctrl: vnode unlocked1"));
                            ret = nfsrv_clientconflict(tstp->ls_clp, &haslock,
                                vp, p);
                            if (ret == 1) {
                                /*
                                * nfsrv_clientconflict unlocks state
                                 * when it returns non-zero.
                                 */
                                lckstp = NULL;
                                goto tryagain;
                            }
                            if (ret == 0)
                                NFSUNLOCKSTATE();
                            if (ret == 2)
                                error = NFSERR_PERM;
                            else
                                error = NFSERR_OPENMODE;
                            goto out;
                        }
                    }
                }

                /* We're outta here */
                NFSUNLOCKSTATE();
                goto out;
            }
        }

        /*
         * For setattr, just get rid of all the Delegations for other clients.
         */
        if (new_stp->ls_flags & NFSLCK_SETATTR) {
                KASSERT(vnode_unlocked == 0,
                    ("nfsrv_lockctrl: vnode unlocked2"));
                ret = nfsrv_cleandeleg(vp, lfp, clp, &haslock, p);
                if (ret) {
                        /*
                         * nfsrv_cleandeleg() unlocks state when it
                         * returns non-zero.
                         */
                        if (ret == -1) {
                                lckstp = NULL;
                                goto tryagain;
                        }
                        error = ret;
                        goto out;
                }
                if (!(new_stp->ls_flags & NFSLCK_CHECK) ||
                    (LIST_EMPTY(&lfp->lf_open) && LIST_EMPTY(&lfp->lf_lock) &&
                     LIST_EMPTY(&lfp->lf_deleg))) {
                        NFSUNLOCKSTATE();
                        goto out;
                }
        }

        /*
         * Check for a conflicting delegation. If one is found, call
         * nfsrv_delegconflict() to handle it. If the v4root lock hasn't
         * been set yet, it will get the lock. Otherwise, it will recall
         * the delegation. Then, we try try again...
         * I currently believe the conflict algorithm to be:
         * For Lock Ops (Lock/LockT/LockU)
         * - there is a conflict iff a different client has a write delegation
         * For Reading (Read Op)
         * - there is a conflict iff a different client has a write delegation
         *   (the specialids are always a different client)
         * For Writing (Write/Setattr of size)
         * - there is a conflict if a different client has any delegation
         * - there is a conflict if the same client has a read delegation
         *   (I don't understand why this isn't allowed, but that seems to be
         *    the current consensus?)
         */
        tstp = LIST_FIRST(&lfp->lf_deleg);
        while (tstp != NULL) {
            nstp = LIST_NEXT(tstp, ls_file);
            if ((((new_stp->ls_flags&(NFSLCK_LOCK|NFSLCK_UNLOCK|NFSLCK_TEST))||
                 ((new_stp->ls_flags & NFSLCK_CHECK) &&
                  (new_lop->lo_flags & NFSLCK_READ))) &&
                  clp != tstp->ls_clp &&
                 (tstp->ls_flags & NFSLCK_DELEGWRITE)) ||
                 ((new_stp->ls_flags & NFSLCK_CHECK) &&
                   (new_lop->lo_flags & NFSLCK_WRITE) &&
                  (clp != tstp->ls_clp ||
                   (tstp->ls_flags & NFSLCK_DELEGREAD)))) {
                ret = 0;
                if (filestruct_locked != 0) {
                        /* Roll back local locks. */
                        NFSUNLOCKSTATE();
                        if (vnode_unlocked == 0) {
                                ASSERT_VOP_ELOCKED(vp, "nfsrv_lockctrl4");
                                NFSVOPUNLOCK(vp, 0);
                        }
                        nfsrv_locallock_rollback(vp, lfp, p);
                        NFSLOCKSTATE();
                        nfsrv_unlocklf(lfp);
                        NFSUNLOCKSTATE();
                        NFSVOPLOCK(vp, LK_EXCLUSIVE | LK_RETRY);
                        vnode_unlocked = 0;
                        if ((vp->v_iflag & VI_DOOMED) != 0)
                                ret = NFSERR_SERVERFAULT;
                        NFSLOCKSTATE();
                }
                if (ret == 0)
                        ret = nfsrv_delegconflict(tstp, &haslock, p, vp);
                if (ret) {
                    /*
                     * nfsrv_delegconflict unlocks state when it
                     * returns non-zero, which it always does.
                     */
                    if (other_lop) {
                        FREE((caddr_t)other_lop, M_NFSDLOCK);
                        other_lop = NULL;
                    }
                    if (ret == -1) {
                        lckstp = NULL;
                        goto tryagain;
                    }
                    error = ret;
                    goto out;
                }
                /* Never gets here. */
            }
            tstp = nstp;
        }

        /*
         * Handle the unlock case by calling nfsrv_updatelock().
         * (Should I have done some access checking above for unlock? For now,
         *  just let it happen.)
         */
        if (new_stp->ls_flags & NFSLCK_UNLOCK) {
                first = new_lop->lo_first;
                end = new_lop->lo_end;
                nfsrv_updatelock(stp, new_lopp, &other_lop, lfp);
                stateidp->seqid = ++(stp->ls_stateid.seqid);
                if ((nd->nd_flag & ND_NFSV41) != 0 && stateidp->seqid == 0)
                        stateidp->seqid = stp->ls_stateid.seqid = 1;
                stateidp->other[0] = stp->ls_stateid.other[0];
                stateidp->other[1] = stp->ls_stateid.other[1];
                stateidp->other[2] = stp->ls_stateid.other[2];
                if (filestruct_locked != 0) {
                        NFSUNLOCKSTATE();
                        if (vnode_unlocked == 0) {
                                ASSERT_VOP_ELOCKED(vp, "nfsrv_lockctrl5");
                                vnode_unlocked = 1;
                                NFSVOPUNLOCK(vp, 0);
                        }
                        /* Update the local locks. */
                        nfsrv_localunlock(vp, lfp, first, end, p);
                        NFSLOCKSTATE();
                        nfsrv_unlocklf(lfp);
                }
                NFSUNLOCKSTATE();
                goto out;
        }

        /*
         * Search for a conflicting lock. A lock conflicts if:
         * - the lock range overlaps and
         * - at least one lock is a write lock and
         * - it is not owned by the same lock owner
         */
        if (!delegation) {
          LIST_FOREACH(lop, &lfp->lf_lock, lo_lckfile) {
            if (new_lop->lo_end > lop->lo_first &&
                new_lop->lo_first < lop->lo_end &&
                (new_lop->lo_flags == NFSLCK_WRITE ||
                 lop->lo_flags == NFSLCK_WRITE) &&
                lckstp != lop->lo_stp &&
                (clp != lop->lo_stp->ls_clp ||
                 lckstp->ls_ownerlen != lop->lo_stp->ls_ownerlen ||
                 NFSBCMP(lckstp->ls_owner, lop->lo_stp->ls_owner,
                    lckstp->ls_ownerlen))) {
                if (other_lop) {
                    FREE((caddr_t)other_lop, M_NFSDLOCK);
                    other_lop = NULL;
                }
                if (vnode_unlocked != 0)
                    ret = nfsrv_clientconflict(lop->lo_stp->ls_clp, &haslock,
                        NULL, p);
                else
                    ret = nfsrv_clientconflict(lop->lo_stp->ls_clp, &haslock,
                        vp, p);
                if (ret == 1) {
                    if (filestruct_locked != 0) {
                        if (vnode_unlocked == 0) {
                                ASSERT_VOP_ELOCKED(vp, "nfsrv_lockctrl6");
                                NFSVOPUNLOCK(vp, 0);
                        }
                        /* Roll back local locks. */
                        nfsrv_locallock_rollback(vp, lfp, p);
                        NFSLOCKSTATE();
                        nfsrv_unlocklf(lfp);
                        NFSUNLOCKSTATE();
                        NFSVOPLOCK(vp, LK_EXCLUSIVE | LK_RETRY);
                        vnode_unlocked = 0;
                        if ((vp->v_iflag & VI_DOOMED) != 0) {
                                error = NFSERR_SERVERFAULT;
                                goto out;
                        }
                    }
                    /*
                     * nfsrv_clientconflict() unlocks state when it
                     * returns non-zero.
                     */
                    lckstp = NULL;
                    goto tryagain;
                }
                /*
                 * Found a conflicting lock, so record the conflict and
                 * return the error.
                 */
                if (cfp != NULL && ret == 0) {
                    cfp->cl_clientid.lval[0]=lop->lo_stp->ls_stateid.other[0];
                    cfp->cl_clientid.lval[1]=lop->lo_stp->ls_stateid.other[1];
                    cfp->cl_first = lop->lo_first;
                    cfp->cl_end = lop->lo_end;
                    cfp->cl_flags = lop->lo_flags;
                    cfp->cl_ownerlen = lop->lo_stp->ls_ownerlen;
                    NFSBCOPY(lop->lo_stp->ls_owner, cfp->cl_owner,
                        cfp->cl_ownerlen);
                }
                if (ret == 2)
                    error = NFSERR_PERM;
                else if (new_stp->ls_flags & NFSLCK_RECLAIM)
                    error = NFSERR_RECLAIMCONFLICT;
                else if (new_stp->ls_flags & NFSLCK_CHECK)
                    error = NFSERR_LOCKED;
                else
                    error = NFSERR_DENIED;
                if (filestruct_locked != 0 && ret == 0) {
                        /* Roll back local locks. */
                        NFSUNLOCKSTATE();
                        if (vnode_unlocked == 0) {
                                ASSERT_VOP_ELOCKED(vp, "nfsrv_lockctrl7");
                                vnode_unlocked = 1;
                                NFSVOPUNLOCK(vp, 0);
                        }
                        nfsrv_locallock_rollback(vp, lfp, p);
                        NFSLOCKSTATE();
                        nfsrv_unlocklf(lfp);
                }
                if (ret == 0)
                        NFSUNLOCKSTATE();
                goto out;
            }
          }
        }

        /*
         * We only get here if there was no lock that conflicted.
         */
        if (new_stp->ls_flags & (NFSLCK_TEST | NFSLCK_CHECK)) {
                NFSUNLOCKSTATE();
                goto out;
        }

        /*
         * We only get here when we are creating or modifying a lock.
         * There are two variants:
         * - exist_lock_owner where lock_owner exists
         * - open_to_lock_owner with new lock_owner
         */
        first = new_lop->lo_first;
        end = new_lop->lo_end;
        lock_flags = new_lop->lo_flags;
        if (!(new_stp->ls_flags & NFSLCK_OPENTOLOCK)) {
                nfsrv_updatelock(lckstp, new_lopp, &other_lop, lfp);
                stateidp->seqid = ++(lckstp->ls_stateid.seqid);
                if ((nd->nd_flag & ND_NFSV41) != 0 && stateidp->seqid == 0)
                        stateidp->seqid = lckstp->ls_stateid.seqid = 1;
                stateidp->other[0] = lckstp->ls_stateid.other[0];
                stateidp->other[1] = lckstp->ls_stateid.other[1];
                stateidp->other[2] = lckstp->ls_stateid.other[2];
        } else {
                /*
                 * The new open_to_lock_owner case.
                 * Link the new nfsstate into the lists.
                 */
                new_stp->ls_seq = new_stp->ls_opentolockseq;
                nfsrvd_refcache(new_stp->ls_op);
                stateidp->seqid = new_stp->ls_stateid.seqid = 1;
                stateidp->other[0] = new_stp->ls_stateid.other[0] =
                    clp->lc_clientid.lval[0];
                stateidp->other[1] = new_stp->ls_stateid.other[1] =
                    clp->lc_clientid.lval[1];
                stateidp->other[2] = new_stp->ls_stateid.other[2] =
                    nfsrv_nextstateindex(clp);
                new_stp->ls_clp = clp;
                LIST_INIT(&new_stp->ls_lock);
                new_stp->ls_openstp = stp;
                new_stp->ls_lfp = lfp;
                nfsrv_insertlock(new_lop, (struct nfslock *)new_stp, new_stp,
                    lfp);
                LIST_INSERT_HEAD(NFSSTATEHASH(clp, new_stp->ls_stateid),
                    new_stp, ls_hash);
                LIST_INSERT_HEAD(&stp->ls_open, new_stp, ls_list);
                *new_lopp = NULL;
                *new_stpp = NULL;
                nfsstatsv1.srvlockowners++;
                nfsrv_openpluslock++;
        }
        if (filestruct_locked != 0) {
                NFSUNLOCKSTATE();
                nfsrv_locallock_commit(lfp, lock_flags, first, end);
                NFSLOCKSTATE();
                nfsrv_unlocklf(lfp);
        }
        NFSUNLOCKSTATE();

out:
        if (haslock) {
                NFSLOCKV4ROOTMUTEX();
                nfsv4_unlock(&nfsv4rootfs_lock, 1);
                NFSUNLOCKV4ROOTMUTEX();
        }
        if (vnode_unlocked != 0) {
                NFSVOPLOCK(vp, LK_EXCLUSIVE | LK_RETRY);
                if (error == 0 && (vp->v_iflag & VI_DOOMED) != 0)
                        error = NFSERR_SERVERFAULT;
        }
        if (other_lop)
                FREE((caddr_t)other_lop, M_NFSDLOCK);
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Check for state errors for Open.
 * repstat is passed back out as an error if more critical errors
 * are not detected.
 */
APPLESTATIC int
nfsrv_opencheck(nfsquad_t clientid, nfsv4stateid_t *stateidp,
    struct nfsstate *new_stp, vnode_t vp, struct nfsrv_descript *nd,
    NFSPROC_T *p, int repstat)
{
        struct nfsstate *stp, *nstp;
        struct nfsclient *clp;
        struct nfsstate *ownerstp;
        struct nfslockfile *lfp, *new_lfp;
        int error = 0, haslock = 0, ret, readonly = 0, getfhret = 0;

        if ((new_stp->ls_flags & NFSLCK_SHAREBITS) == NFSLCK_READACCESS)
                readonly = 1;
        /*
         * Check for restart conditions (client and server).
         */
        error = nfsrv_checkrestart(clientid, new_stp->ls_flags,
                &new_stp->ls_stateid, 0);
        if (error)
                goto out;

        /*
         * Check for state resource limit exceeded.
         * Technically this should be SMP protected, but the worst
         * case error is "out by one or two" on the count when it
         * returns NFSERR_RESOURCE and the limit is just a rather
         * arbitrary high water mark, so no harm is done.
         */
        if (nfsrv_openpluslock > nfsrv_v4statelimit) {
                error = NFSERR_RESOURCE;
                goto out;
        }

tryagain:
        MALLOC(new_lfp, struct nfslockfile *, sizeof (struct nfslockfile),
            M_NFSDLOCKFILE, M_WAITOK);
        if (vp)
                getfhret = nfsrv_getlockfh(vp, new_stp->ls_flags, new_lfp,
                    NULL, p);
        NFSLOCKSTATE();
        /*
         * Get the nfsclient structure.
         */
        error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp, NULL,
            (nfsquad_t)((u_quad_t)0), 0, nd, p);

        /*
         * Look up the open owner. See if it needs confirmation and
         * check the seq#, as required.
         */
        if (!error)
                nfsrv_getowner(&clp->lc_open, new_stp, &ownerstp);

        if (!error && ownerstp) {
                error = nfsrv_checkseqid(nd, new_stp->ls_seq, ownerstp,
                    new_stp->ls_op);
                /*
                 * If the OpenOwner hasn't been confirmed, assume the
                 * old one was a replay and this one is ok.
                 * See: RFC3530 Sec. 14.2.18.
                 */
                if (error == NFSERR_BADSEQID &&
                    (ownerstp->ls_flags & NFSLCK_NEEDSCONFIRM))
                        error = 0;
        }

        /*
         * Check for grace.
         */
        if (!error)
                error = nfsrv_checkgrace(nd, clp, new_stp->ls_flags);
        if ((new_stp->ls_flags & NFSLCK_RECLAIM) && !error &&
                nfsrv_checkstable(clp))
                error = NFSERR_NOGRACE;

        /*
         * If none of the above errors occurred, let repstat be
         * returned.
         */
        if (repstat && !error)
                error = repstat;
        if (error) {
                NFSUNLOCKSTATE();
                if (haslock) {
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                }
                free((caddr_t)new_lfp, M_NFSDLOCKFILE);
                goto out;
        }

        /*
         * If vp == NULL, the file doesn't exist yet, so return ok.
         * (This always happens on the first pass, so haslock must be 0.)
         */
        if (vp == NULL) {
                NFSUNLOCKSTATE();
                FREE((caddr_t)new_lfp, M_NFSDLOCKFILE);
                goto out;
        }

        /*
         * Get the structure for the underlying file.
         */
        if (getfhret)
                error = getfhret;
        else
                error = nfsrv_getlockfile(new_stp->ls_flags, &new_lfp, &lfp,
                    NULL, 0);
        if (new_lfp)
                FREE((caddr_t)new_lfp, M_NFSDLOCKFILE);
        if (error) {
                NFSUNLOCKSTATE();
                if (haslock) {
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                }
                goto out;
        }

        /*
         * Search for a conflicting open/share.
         */
        if (new_stp->ls_flags & NFSLCK_DELEGCUR) {
            /*
             * For Delegate_Cur, search for the matching Delegation,
             * which indicates no conflict.
             * An old delegation should have been recovered by the
             * client doing a Claim_DELEGATE_Prev, so I won't let
             * it match and return NFSERR_EXPIRED. Should I let it
             * match?
             */
            LIST_FOREACH(stp, &lfp->lf_deleg, ls_file) {
                if (!(stp->ls_flags & NFSLCK_OLDDELEG) &&
                    (((nd->nd_flag & ND_NFSV41) != 0 &&
                    stateidp->seqid == 0) ||
                    stateidp->seqid == stp->ls_stateid.seqid) &&
                    !NFSBCMP(stateidp->other, stp->ls_stateid.other,
                          NFSX_STATEIDOTHER))
                        break;
            }
            if (stp == NULL ||
                ((new_stp->ls_flags & NFSLCK_WRITEACCESS) &&
                 (stp->ls_flags & NFSLCK_DELEGREAD))) {
                NFSUNLOCKSTATE();
                if (haslock) {
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                }
                error = NFSERR_EXPIRED;
                goto out;
            }
        }

        /*
         * Check for access/deny bit conflicts. I check for the same
         * owner as well, in case the client didn't bother.
         */
        LIST_FOREACH(stp, &lfp->lf_open, ls_file) {
                if (!(new_stp->ls_flags & NFSLCK_DELEGCUR) &&
                    (((new_stp->ls_flags & NFSLCK_ACCESSBITS) &
                      ((stp->ls_flags>>NFSLCK_SHIFT) & NFSLCK_ACCESSBITS))||
                     ((stp->ls_flags & NFSLCK_ACCESSBITS) &
                      ((new_stp->ls_flags>>NFSLCK_SHIFT)&NFSLCK_ACCESSBITS)))){
                        ret = nfsrv_clientconflict(stp->ls_clp,&haslock,vp,p);
                        if (ret == 1) {
                                /*
                                 * nfsrv_clientconflict() unlocks
                                 * state when it returns non-zero.
                                 */
                                goto tryagain;
                        }
                        if (ret == 2)
                                error = NFSERR_PERM;
                        else if (new_stp->ls_flags & NFSLCK_RECLAIM)
                                error = NFSERR_RECLAIMCONFLICT;
                        else
                                error = NFSERR_SHAREDENIED;
                        if (ret == 0)
                                NFSUNLOCKSTATE();
                        if (haslock) {
                                NFSLOCKV4ROOTMUTEX();
                                nfsv4_unlock(&nfsv4rootfs_lock, 1);
                                NFSUNLOCKV4ROOTMUTEX();
                        }
                        goto out;
                }
        }

        /*
         * Check for a conflicting delegation. If one is found, call
         * nfsrv_delegconflict() to handle it. If the v4root lock hasn't
         * been set yet, it will get the lock. Otherwise, it will recall
         * the delegation. Then, we try try again...
         * (If NFSLCK_DELEGCUR is set, it has a delegation, so there
         *  isn't a conflict.)
         * I currently believe the conflict algorithm to be:
         * For Open with Read Access and Deny None
         * - there is a conflict iff a different client has a write delegation
         * For Open with other Write Access or any Deny except None
         * - there is a conflict if a different client has any delegation
         * - there is a conflict if the same client has a read delegation
         *   (The current consensus is that this last case should be
         *    considered a conflict since the client with a read delegation
         *    could have done an Open with ReadAccess and WriteDeny
         *    locally and then not have checked for the WriteDeny.)
         * Don't check for a Reclaim, since that will be dealt with
         * by nfsrv_openctrl().
         */
        if (!(new_stp->ls_flags &
                (NFSLCK_DELEGPREV | NFSLCK_DELEGCUR | NFSLCK_RECLAIM))) {
            stp = LIST_FIRST(&lfp->lf_deleg);
            while (stp != NULL) {
                nstp = LIST_NEXT(stp, ls_file);
                if ((readonly && stp->ls_clp != clp &&
                       (stp->ls_flags & NFSLCK_DELEGWRITE)) ||
                    (!readonly && (stp->ls_clp != clp ||
                         (stp->ls_flags & NFSLCK_DELEGREAD)))) {
                        ret = nfsrv_delegconflict(stp, &haslock, p, vp);
                        if (ret) {
                            /*
                             * nfsrv_delegconflict() unlocks state
                             * when it returns non-zero.
                             */
                            if (ret == -1)
                                goto tryagain;
                            error = ret;
                            goto out;
                        }
                }
                stp = nstp;
            }
        }
        NFSUNLOCKSTATE();
        if (haslock) {
                NFSLOCKV4ROOTMUTEX();
                nfsv4_unlock(&nfsv4rootfs_lock, 1);
                NFSUNLOCKV4ROOTMUTEX();
        }

out:
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Open control function to create/update open state for an open.
 */
APPLESTATIC int
nfsrv_openctrl(struct nfsrv_descript *nd, vnode_t vp,
    struct nfsstate **new_stpp, nfsquad_t clientid, nfsv4stateid_t *stateidp,
    nfsv4stateid_t *delegstateidp, u_int32_t *rflagsp, struct nfsexstuff *exp,
    NFSPROC_T *p, u_quad_t filerev)
{
        struct nfsstate *new_stp = *new_stpp;
        struct nfsstate *stp, *nstp;
        struct nfsstate *openstp = NULL, *new_open, *ownerstp, *new_deleg;
        struct nfslockfile *lfp, *new_lfp;
        struct nfsclient *clp;
        int error = 0, haslock = 0, ret, delegate = 1, writedeleg = 1;
        int readonly = 0, cbret = 1, getfhret = 0;

        if ((new_stp->ls_flags & NFSLCK_SHAREBITS) == NFSLCK_READACCESS)
                readonly = 1;
        /*
         * Check for restart conditions (client and server).
         * (Paranoia, should have been detected by nfsrv_opencheck().)
         * If an error does show up, return NFSERR_EXPIRED, since the
         * the seqid# has already been incremented.
         */
        error = nfsrv_checkrestart(clientid, new_stp->ls_flags,
            &new_stp->ls_stateid, 0);
        if (error) {
                printf("Nfsd: openctrl unexpected restart err=%d\n",
                    error);
                error = NFSERR_EXPIRED;
                goto out;
        }

tryagain:
        MALLOC(new_lfp, struct nfslockfile *, sizeof (struct nfslockfile),
            M_NFSDLOCKFILE, M_WAITOK);
        MALLOC(new_open, struct nfsstate *, sizeof (struct nfsstate),
            M_NFSDSTATE, M_WAITOK);
        MALLOC(new_deleg, struct nfsstate *, sizeof (struct nfsstate),
            M_NFSDSTATE, M_WAITOK);
        getfhret = nfsrv_getlockfh(vp, new_stp->ls_flags, new_lfp,
            NULL, p);
        NFSLOCKSTATE();
        /*
         * Get the client structure. Since the linked lists could be changed
         * by other nfsd processes if this process does a tsleep(), one of
         * two things must be done.
         * 1 - don't tsleep()
         * or
         * 2 - get the nfsv4_lock() { indicated by haslock == 1 }
         *     before using the lists, since this lock stops the other
         *     nfsd. This should only be used for rare cases, since it
         *     essentially single threads the nfsd.
         *     At this time, it is only done for cases where the stable
         *     storage file must be written prior to completion of state
         *     expiration.
         */
        error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp, NULL,
            (nfsquad_t)((u_quad_t)0), 0, nd, p);
        if (!error && (clp->lc_flags & LCL_NEEDSCBNULL) &&
            clp->lc_program) {
                /*
                 * This happens on the first open for a client
                 * that supports callbacks.
                 */
                NFSUNLOCKSTATE();
                /*
                 * Although nfsrv_docallback() will sleep, clp won't
                 * go away, since they are only removed when the
                 * nfsv4_lock() has blocked the nfsd threads. The
                 * fields in clp can change, but having multiple
                 * threads do this Null callback RPC should be
                 * harmless.
                 */
                cbret = nfsrv_docallback(clp, NFSV4PROC_CBNULL,
                    NULL, 0, NULL, NULL, NULL, p);
                NFSLOCKSTATE();
                clp->lc_flags &= ~LCL_NEEDSCBNULL;
                if (!cbret)
                        clp->lc_flags |= LCL_CALLBACKSON;
        }

        /*
         * Look up the open owner. See if it needs confirmation and
         * check the seq#, as required.
         */
        if (!error)
                nfsrv_getowner(&clp->lc_open, new_stp, &ownerstp);

        if (error) {
                NFSUNLOCKSTATE();
                printf("Nfsd: openctrl unexpected state err=%d\n",
                        error);
                free((caddr_t)new_lfp, M_NFSDLOCKFILE);
                free((caddr_t)new_open, M_NFSDSTATE);
                free((caddr_t)new_deleg, M_NFSDSTATE);
                if (haslock) {
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                }
                error = NFSERR_EXPIRED;
                goto out;
        }

        if (new_stp->ls_flags & NFSLCK_RECLAIM)
                nfsrv_markstable(clp);

        /*
         * Get the structure for the underlying file.
         */
        if (getfhret)
                error = getfhret;
        else
                error = nfsrv_getlockfile(new_stp->ls_flags, &new_lfp, &lfp,
                    NULL, 0);
        if (new_lfp)
                FREE((caddr_t)new_lfp, M_NFSDLOCKFILE);
        if (error) {
                NFSUNLOCKSTATE();
                printf("Nfsd openctrl unexpected getlockfile err=%d\n",
                    error);
                free((caddr_t)new_open, M_NFSDSTATE);
                free((caddr_t)new_deleg, M_NFSDSTATE);
                if (haslock) {
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                }
                goto out;
        }

        /*
         * Search for a conflicting open/share.
         */
        if (new_stp->ls_flags & NFSLCK_DELEGCUR) {
            /*
             * For Delegate_Cur, search for the matching Delegation,
             * which indicates no conflict.
             * An old delegation should have been recovered by the
             * client doing a Claim_DELEGATE_Prev, so I won't let
             * it match and return NFSERR_EXPIRED. Should I let it
             * match?
             */
            LIST_FOREACH(stp, &lfp->lf_deleg, ls_file) {
                if (!(stp->ls_flags & NFSLCK_OLDDELEG) &&
                    (((nd->nd_flag & ND_NFSV41) != 0 &&
                    stateidp->seqid == 0) ||
                    stateidp->seqid == stp->ls_stateid.seqid) &&
                    !NFSBCMP(stateidp->other, stp->ls_stateid.other,
                        NFSX_STATEIDOTHER))
                        break;
            }
            if (stp == NULL ||
                ((new_stp->ls_flags & NFSLCK_WRITEACCESS) &&
                 (stp->ls_flags & NFSLCK_DELEGREAD))) {
                NFSUNLOCKSTATE();
                printf("Nfsd openctrl unexpected expiry\n");
                free((caddr_t)new_open, M_NFSDSTATE);
                free((caddr_t)new_deleg, M_NFSDSTATE);
                if (haslock) {
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                }
                error = NFSERR_EXPIRED;
                goto out;
            }

            /*
             * Don't issue a Delegation, since one already exists and
             * delay delegation timeout, as required.
             */
            delegate = 0;
            nfsrv_delaydelegtimeout(stp);
        }

        /*
         * Check for access/deny bit conflicts. I also check for the
         * same owner, since the client might not have bothered to check.
         * Also, note an open for the same file and owner, if found,
         * which is all we do here for Delegate_Cur, since conflict
         * checking is already done.
         */
        LIST_FOREACH(stp, &lfp->lf_open, ls_file) {
                if (ownerstp && stp->ls_openowner == ownerstp)
                        openstp = stp;
                if (!(new_stp->ls_flags & NFSLCK_DELEGCUR)) {
                    /*
                     * If another client has the file open, the only
                     * delegation that can be issued is a Read delegation
                     * and only if it is a Read open with Deny none.
                     */
                    if (clp != stp->ls_clp) {
                        if ((stp->ls_flags & NFSLCK_SHAREBITS) ==
                            NFSLCK_READACCESS)
                            writedeleg = 0;
                        else
                            delegate = 0;
                    }
                    if(((new_stp->ls_flags & NFSLCK_ACCESSBITS) &
                        ((stp->ls_flags>>NFSLCK_SHIFT) & NFSLCK_ACCESSBITS))||
                       ((stp->ls_flags & NFSLCK_ACCESSBITS) &
                        ((new_stp->ls_flags>>NFSLCK_SHIFT)&NFSLCK_ACCESSBITS))){
                        ret = nfsrv_clientconflict(stp->ls_clp,&haslock,vp,p);
                        if (ret == 1) {
                                /*
                                 * nfsrv_clientconflict() unlocks state
                                 * when it returns non-zero.
                                 */
                                free((caddr_t)new_open, M_NFSDSTATE);
                                free((caddr_t)new_deleg, M_NFSDSTATE);
                                openstp = NULL;
                                goto tryagain;
                        }
                        if (ret == 2)
                                error = NFSERR_PERM;
                        else if (new_stp->ls_flags & NFSLCK_RECLAIM)
                                error = NFSERR_RECLAIMCONFLICT;
                        else
                                error = NFSERR_SHAREDENIED;
                        if (ret == 0)
                                NFSUNLOCKSTATE();
                        if (haslock) {
                                NFSLOCKV4ROOTMUTEX();
                                nfsv4_unlock(&nfsv4rootfs_lock, 1);
                                NFSUNLOCKV4ROOTMUTEX();
                        }
                        free((caddr_t)new_open, M_NFSDSTATE);
                        free((caddr_t)new_deleg, M_NFSDSTATE);
                        printf("nfsd openctrl unexpected client cnfl\n");
                        goto out;
                    }
                }
        }

        /*
         * Check for a conflicting delegation. If one is found, call
         * nfsrv_delegconflict() to handle it. If the v4root lock hasn't
         * been set yet, it will get the lock. Otherwise, it will recall
         * the delegation. Then, we try try again...
         * (If NFSLCK_DELEGCUR is set, it has a delegation, so there
         *  isn't a conflict.)
         * I currently believe the conflict algorithm to be:
         * For Open with Read Access and Deny None
         * - there is a conflict iff a different client has a write delegation
         * For Open with other Write Access or any Deny except None
         * - there is a conflict if a different client has any delegation
         * - there is a conflict if the same client has a read delegation
         *   (The current consensus is that this last case should be
         *    considered a conflict since the client with a read delegation
         *    could have done an Open with ReadAccess and WriteDeny
         *    locally and then not have checked for the WriteDeny.)
         */
        if (!(new_stp->ls_flags & (NFSLCK_DELEGPREV | NFSLCK_DELEGCUR))) {
            stp = LIST_FIRST(&lfp->lf_deleg);
            while (stp != NULL) {
                nstp = LIST_NEXT(stp, ls_file);
                if (stp->ls_clp != clp && (stp->ls_flags & NFSLCK_DELEGREAD))
                        writedeleg = 0;
                else
                        delegate = 0;
                if ((readonly && stp->ls_clp != clp &&
                       (stp->ls_flags & NFSLCK_DELEGWRITE)) ||
                    (!readonly && (stp->ls_clp != clp ||
                         (stp->ls_flags & NFSLCK_DELEGREAD)))) {
                    if (new_stp->ls_flags & NFSLCK_RECLAIM) {
                        delegate = 2;
                    } else {
                        ret = nfsrv_delegconflict(stp, &haslock, p, vp);
                        if (ret) {
                            /*
                             * nfsrv_delegconflict() unlocks state
                             * when it returns non-zero.
                             */
                            printf("Nfsd openctrl unexpected deleg cnfl\n");
                            free((caddr_t)new_open, M_NFSDSTATE);
                            free((caddr_t)new_deleg, M_NFSDSTATE);
                            if (ret == -1) {
                                openstp = NULL;
                                goto tryagain;
                            }
                            error = ret;
                            goto out;
                        }
                    }
                }
                stp = nstp;
            }
        }

        /*
         * We only get here if there was no open that conflicted.
         * If an open for the owner exists, or in the access/deny bits.
         * Otherwise it is a new open. If the open_owner hasn't been
         * confirmed, replace the open with the new one needing confirmation,
         * otherwise add the open.
         */
        if (new_stp->ls_flags & NFSLCK_DELEGPREV) {
            /*
             * Handle NFSLCK_DELEGPREV by searching the old delegations for
             * a match. If found, just move the old delegation to the current
             * delegation list and issue open. If not found, return
             * NFSERR_EXPIRED.
             */
            LIST_FOREACH(stp, &clp->lc_olddeleg, ls_list) {
                if (stp->ls_lfp == lfp) {
                    /* Found it */
                    if (stp->ls_clp != clp)
                        panic("olddeleg clp");
                    LIST_REMOVE(stp, ls_list);
                    LIST_REMOVE(stp, ls_hash);
                    stp->ls_flags &= ~NFSLCK_OLDDELEG;
                    stp->ls_stateid.seqid = delegstateidp->seqid = 1;
                    stp->ls_stateid.other[0] = delegstateidp->other[0] =
                        clp->lc_clientid.lval[0];
                    stp->ls_stateid.other[1] = delegstateidp->other[1] =
                        clp->lc_clientid.lval[1];
                    stp->ls_stateid.other[2] = delegstateidp->other[2] =
                        nfsrv_nextstateindex(clp);
                    stp->ls_compref = nd->nd_compref;
                    LIST_INSERT_HEAD(&clp->lc_deleg, stp, ls_list);
                    LIST_INSERT_HEAD(NFSSTATEHASH(clp,
                        stp->ls_stateid), stp, ls_hash);
                    if (stp->ls_flags & NFSLCK_DELEGWRITE)
                        *rflagsp |= NFSV4OPEN_WRITEDELEGATE;
                    else
                        *rflagsp |= NFSV4OPEN_READDELEGATE;
                    clp->lc_delegtime = NFSD_MONOSEC +
                        nfsrv_lease + NFSRV_LEASEDELTA;

                    /*
                     * Now, do the associated open.
                     */
                    new_open->ls_stateid.seqid = 1;
                    new_open->ls_stateid.other[0] = clp->lc_clientid.lval[0];
                    new_open->ls_stateid.other[1] = clp->lc_clientid.lval[1];
                    new_open->ls_stateid.other[2] = nfsrv_nextstateindex(clp);
                    new_open->ls_flags = (new_stp->ls_flags&NFSLCK_DENYBITS)|
                        NFSLCK_OPEN;
                    if (stp->ls_flags & NFSLCK_DELEGWRITE)
                        new_open->ls_flags |= (NFSLCK_READACCESS |
                            NFSLCK_WRITEACCESS);
                    else
                        new_open->ls_flags |= NFSLCK_READACCESS;
                    new_open->ls_uid = new_stp->ls_uid;
                    new_open->ls_lfp = lfp;
                    new_open->ls_clp = clp;
                    LIST_INIT(&new_open->ls_open);
                    LIST_INSERT_HEAD(&lfp->lf_open, new_open, ls_file);
                    LIST_INSERT_HEAD(NFSSTATEHASH(clp, new_open->ls_stateid),
                        new_open, ls_hash);
                    /*
                     * and handle the open owner
                     */
                    if (ownerstp) {
                        new_open->ls_openowner = ownerstp;
                        LIST_INSERT_HEAD(&ownerstp->ls_open,new_open,ls_list);
                    } else {
                        new_open->ls_openowner = new_stp;
                        new_stp->ls_flags = 0;
                        nfsrvd_refcache(new_stp->ls_op);
                        new_stp->ls_noopens = 0;
                        LIST_INIT(&new_stp->ls_open);
                        LIST_INSERT_HEAD(&new_stp->ls_open, new_open, ls_list);
                        LIST_INSERT_HEAD(&clp->lc_open, new_stp, ls_list);
                        *new_stpp = NULL;
                        nfsstatsv1.srvopenowners++;
                        nfsrv_openpluslock++;
                    }
                    openstp = new_open;
                    new_open = NULL;
                    nfsstatsv1.srvopens++;
                    nfsrv_openpluslock++;
                    break;
                }
            }
            if (stp == NULL)
                error = NFSERR_EXPIRED;
        } else if (new_stp->ls_flags & (NFSLCK_DELEGREAD | NFSLCK_DELEGWRITE)) {
            /*
             * Scan to see that no delegation for this client and file
             * doesn't already exist.
             * There also shouldn't yet be an Open for this file and
             * openowner.
             */
            LIST_FOREACH(stp, &lfp->lf_deleg, ls_file) {
                if (stp->ls_clp == clp)
                    break;
            }
            if (stp == NULL && openstp == NULL) {
                /*
                 * This is the Claim_Previous case with a delegation
                 * type != Delegate_None.
                 */
                /*
                 * First, add the delegation. (Although we must issue the
                 * delegation, we can also ask for an immediate return.)
                 */
                new_deleg->ls_stateid.seqid = delegstateidp->seqid = 1;
                new_deleg->ls_stateid.other[0] = delegstateidp->other[0] =
                    clp->lc_clientid.lval[0];
                new_deleg->ls_stateid.other[1] = delegstateidp->other[1] =
                    clp->lc_clientid.lval[1];
                new_deleg->ls_stateid.other[2] = delegstateidp->other[2] =
                    nfsrv_nextstateindex(clp);
                if (new_stp->ls_flags & NFSLCK_DELEGWRITE) {
                    new_deleg->ls_flags = (NFSLCK_DELEGWRITE |
                        NFSLCK_READACCESS | NFSLCK_WRITEACCESS);
                    *rflagsp |= NFSV4OPEN_WRITEDELEGATE;
                } else {
                    new_deleg->ls_flags = (NFSLCK_DELEGREAD |
                        NFSLCK_READACCESS);
                    *rflagsp |= NFSV4OPEN_READDELEGATE;
                }
                new_deleg->ls_uid = new_stp->ls_uid;
                new_deleg->ls_lfp = lfp;
                new_deleg->ls_clp = clp;
                new_deleg->ls_filerev = filerev;
                new_deleg->ls_compref = nd->nd_compref;
                LIST_INSERT_HEAD(&lfp->lf_deleg, new_deleg, ls_file);
                LIST_INSERT_HEAD(NFSSTATEHASH(clp,
                    new_deleg->ls_stateid), new_deleg, ls_hash);
                LIST_INSERT_HEAD(&clp->lc_deleg, new_deleg, ls_list);
                new_deleg = NULL;
                if (delegate == 2 || nfsrv_issuedelegs == 0 ||
                    (clp->lc_flags & (LCL_CALLBACKSON | LCL_CBDOWN)) !=
                     LCL_CALLBACKSON ||
                    NFSRV_V4DELEGLIMIT(nfsrv_delegatecnt) ||
                    !NFSVNO_DELEGOK(vp))
                    *rflagsp |= NFSV4OPEN_RECALL;
                nfsstatsv1.srvdelegates++;
                nfsrv_openpluslock++;
                nfsrv_delegatecnt++;

                /*
                 * Now, do the associated open.
                 */
                new_open->ls_stateid.seqid = 1;
                new_open->ls_stateid.other[0] = clp->lc_clientid.lval[0];
                new_open->ls_stateid.other[1] = clp->lc_clientid.lval[1];
                new_open->ls_stateid.other[2] = nfsrv_nextstateindex(clp);
                new_open->ls_flags = (new_stp->ls_flags & NFSLCK_DENYBITS) |
                    NFSLCK_OPEN;
                if (new_stp->ls_flags & NFSLCK_DELEGWRITE)
                        new_open->ls_flags |= (NFSLCK_READACCESS |
                            NFSLCK_WRITEACCESS);
                else
                        new_open->ls_flags |= NFSLCK_READACCESS;
                new_open->ls_uid = new_stp->ls_uid;
                new_open->ls_lfp = lfp;
                new_open->ls_clp = clp;
                LIST_INIT(&new_open->ls_open);
                LIST_INSERT_HEAD(&lfp->lf_open, new_open, ls_file);
                LIST_INSERT_HEAD(NFSSTATEHASH(clp, new_open->ls_stateid),
                   new_open, ls_hash);
                /*
                 * and handle the open owner
                 */
                if (ownerstp) {
                    new_open->ls_openowner = ownerstp;
                    LIST_INSERT_HEAD(&ownerstp->ls_open, new_open, ls_list);
                } else {
                    new_open->ls_openowner = new_stp;
                    new_stp->ls_flags = 0;
                    nfsrvd_refcache(new_stp->ls_op);
                    new_stp->ls_noopens = 0;
                    LIST_INIT(&new_stp->ls_open);
                    LIST_INSERT_HEAD(&new_stp->ls_open, new_open, ls_list);
                    LIST_INSERT_HEAD(&clp->lc_open, new_stp, ls_list);
                    *new_stpp = NULL;
                    nfsstatsv1.srvopenowners++;
                    nfsrv_openpluslock++;
                }
                openstp = new_open;
                new_open = NULL;
                nfsstatsv1.srvopens++;
                nfsrv_openpluslock++;
            } else {
                error = NFSERR_RECLAIMCONFLICT;
            }
        } else if (ownerstp) {
                if (ownerstp->ls_flags & NFSLCK_NEEDSCONFIRM) {
                    /* Replace the open */
                    if (ownerstp->ls_op)
                        nfsrvd_derefcache(ownerstp->ls_op);
                    ownerstp->ls_op = new_stp->ls_op;
                    nfsrvd_refcache(ownerstp->ls_op);
                    ownerstp->ls_seq = new_stp->ls_seq;
                    *rflagsp |= NFSV4OPEN_RESULTCONFIRM;
                    stp = LIST_FIRST(&ownerstp->ls_open);
                    stp->ls_flags = (new_stp->ls_flags & NFSLCK_SHAREBITS) |
                        NFSLCK_OPEN;
                    stp->ls_stateid.seqid = 1;
                    stp->ls_uid = new_stp->ls_uid;
                    if (lfp != stp->ls_lfp) {
                        LIST_REMOVE(stp, ls_file);
                        LIST_INSERT_HEAD(&lfp->lf_open, stp, ls_file);
                        stp->ls_lfp = lfp;
                    }
                    openstp = stp;
                } else if (openstp) {
                    openstp->ls_flags |= (new_stp->ls_flags & NFSLCK_SHAREBITS);
                    openstp->ls_stateid.seqid++;
                    if ((nd->nd_flag & ND_NFSV41) != 0 &&
                        openstp->ls_stateid.seqid == 0)
                        openstp->ls_stateid.seqid = 1;

                    /*
                     * This is where we can choose to issue a delegation.
                     */
                    if (delegate == 0 || writedeleg == 0 ||
                        NFSVNO_EXRDONLY(exp) || (readonly != 0 &&
                        nfsrv_writedelegifpos == 0) ||
                        !NFSVNO_DELEGOK(vp) ||
                        (new_stp->ls_flags & NFSLCK_WANTRDELEG) != 0 ||
                        (clp->lc_flags & (LCL_CALLBACKSON | LCL_CBDOWN)) !=
                         LCL_CALLBACKSON)
                        *rflagsp |= NFSV4OPEN_WDCONTENTION;
                    else if (nfsrv_issuedelegs == 0 ||
                        NFSRV_V4DELEGLIMIT(nfsrv_delegatecnt))
                        *rflagsp |= NFSV4OPEN_WDRESOURCE;
                    else if ((new_stp->ls_flags & NFSLCK_WANTNODELEG) != 0)
                        *rflagsp |= NFSV4OPEN_WDNOTWANTED;
                    else {
                        new_deleg->ls_stateid.seqid = delegstateidp->seqid = 1;
                        new_deleg->ls_stateid.other[0] = delegstateidp->other[0]
                            = clp->lc_clientid.lval[0];
                        new_deleg->ls_stateid.other[1] = delegstateidp->other[1]
                            = clp->lc_clientid.lval[1];
                        new_deleg->ls_stateid.other[2] = delegstateidp->other[2]
                            = nfsrv_nextstateindex(clp);
                        new_deleg->ls_flags = (NFSLCK_DELEGWRITE |
                            NFSLCK_READACCESS | NFSLCK_WRITEACCESS);
                        *rflagsp |= NFSV4OPEN_WRITEDELEGATE;
                        new_deleg->ls_uid = new_stp->ls_uid;
                        new_deleg->ls_lfp = lfp;
                        new_deleg->ls_clp = clp;
                        new_deleg->ls_filerev = filerev;
                        new_deleg->ls_compref = nd->nd_compref;
                        LIST_INSERT_HEAD(&lfp->lf_deleg, new_deleg, ls_file);
                        LIST_INSERT_HEAD(NFSSTATEHASH(clp,
                            new_deleg->ls_stateid), new_deleg, ls_hash);
                        LIST_INSERT_HEAD(&clp->lc_deleg, new_deleg, ls_list);
                        new_deleg = NULL;
                        nfsstatsv1.srvdelegates++;
                        nfsrv_openpluslock++;
                        nfsrv_delegatecnt++;
                    }
                } else {
                    new_open->ls_stateid.seqid = 1;
                    new_open->ls_stateid.other[0] = clp->lc_clientid.lval[0];
                    new_open->ls_stateid.other[1] = clp->lc_clientid.lval[1];
                    new_open->ls_stateid.other[2] = nfsrv_nextstateindex(clp);
                    new_open->ls_flags = (new_stp->ls_flags & NFSLCK_SHAREBITS)|
                        NFSLCK_OPEN;
                    new_open->ls_uid = new_stp->ls_uid;
                    new_open->ls_openowner = ownerstp;
                    new_open->ls_lfp = lfp;
                    new_open->ls_clp = clp;
                    LIST_INIT(&new_open->ls_open);
                    LIST_INSERT_HEAD(&lfp->lf_open, new_open, ls_file);
                    LIST_INSERT_HEAD(&ownerstp->ls_open, new_open, ls_list);
                    LIST_INSERT_HEAD(NFSSTATEHASH(clp, new_open->ls_stateid),
                        new_open, ls_hash);
                    openstp = new_open;
                    new_open = NULL;
                    nfsstatsv1.srvopens++;
                    nfsrv_openpluslock++;

                    /*
                     * This is where we can choose to issue a delegation.
                     */
                    if (delegate == 0 || (writedeleg == 0 && readonly == 0) ||
                        !NFSVNO_DELEGOK(vp) ||
                        (clp->lc_flags & (LCL_CALLBACKSON | LCL_CBDOWN)) !=
                         LCL_CALLBACKSON)
                        *rflagsp |= NFSV4OPEN_WDCONTENTION;
                    else if (nfsrv_issuedelegs == 0 ||
                        NFSRV_V4DELEGLIMIT(nfsrv_delegatecnt))
                        *rflagsp |= NFSV4OPEN_WDRESOURCE;
                    else if ((new_stp->ls_flags & NFSLCK_WANTNODELEG) != 0)
                        *rflagsp |= NFSV4OPEN_WDNOTWANTED;
                    else {
                        new_deleg->ls_stateid.seqid = delegstateidp->seqid = 1;
                        new_deleg->ls_stateid.other[0] = delegstateidp->other[0]
                            = clp->lc_clientid.lval[0];
                        new_deleg->ls_stateid.other[1] = delegstateidp->other[1]
                            = clp->lc_clientid.lval[1];
                        new_deleg->ls_stateid.other[2] = delegstateidp->other[2]
                            = nfsrv_nextstateindex(clp);
                        if (writedeleg && !NFSVNO_EXRDONLY(exp) &&
                            (nfsrv_writedelegifpos || !readonly) &&
                            (new_stp->ls_flags & NFSLCK_WANTRDELEG) == 0) {
                            new_deleg->ls_flags = (NFSLCK_DELEGWRITE |
                                NFSLCK_READACCESS | NFSLCK_WRITEACCESS);
                            *rflagsp |= NFSV4OPEN_WRITEDELEGATE;
                        } else {
                            new_deleg->ls_flags = (NFSLCK_DELEGREAD |
                                NFSLCK_READACCESS);
                            *rflagsp |= NFSV4OPEN_READDELEGATE;
                        }
                        new_deleg->ls_uid = new_stp->ls_uid;
                        new_deleg->ls_lfp = lfp;
                        new_deleg->ls_clp = clp;
                        new_deleg->ls_filerev = filerev;
                        new_deleg->ls_compref = nd->nd_compref;
                        LIST_INSERT_HEAD(&lfp->lf_deleg, new_deleg, ls_file);
                        LIST_INSERT_HEAD(NFSSTATEHASH(clp,
                            new_deleg->ls_stateid), new_deleg, ls_hash);
                        LIST_INSERT_HEAD(&clp->lc_deleg, new_deleg, ls_list);
                        new_deleg = NULL;
                        nfsstatsv1.srvdelegates++;
                        nfsrv_openpluslock++;
                        nfsrv_delegatecnt++;
                    }
                }
        } else {
                /*
                 * New owner case. Start the open_owner sequence with a
                 * Needs confirmation (unless a reclaim) and hang the
                 * new open off it.
                 */
                new_open->ls_stateid.seqid = 1;
                new_open->ls_stateid.other[0] = clp->lc_clientid.lval[0];
                new_open->ls_stateid.other[1] = clp->lc_clientid.lval[1];
                new_open->ls_stateid.other[2] = nfsrv_nextstateindex(clp);
                new_open->ls_flags = (new_stp->ls_flags & NFSLCK_SHAREBITS) |
                    NFSLCK_OPEN;
                new_open->ls_uid = new_stp->ls_uid;
                LIST_INIT(&new_open->ls_open);
                new_open->ls_openowner = new_stp;
                new_open->ls_lfp = lfp;
                new_open->ls_clp = clp;
                LIST_INSERT_HEAD(&lfp->lf_open, new_open, ls_file);
                if (new_stp->ls_flags & NFSLCK_RECLAIM) {
                        new_stp->ls_flags = 0;
                } else if ((nd->nd_flag & ND_NFSV41) != 0) {
                        /* NFSv4.1 never needs confirmation. */
                        new_stp->ls_flags = 0;

                        /*
                         * This is where we can choose to issue a delegation.
                         */
                        if (delegate && nfsrv_issuedelegs &&
                            (writedeleg || readonly) &&
                            (clp->lc_flags & (LCL_CALLBACKSON | LCL_CBDOWN)) ==
                             LCL_CALLBACKSON &&
                            !NFSRV_V4DELEGLIMIT(nfsrv_delegatecnt) &&
                            NFSVNO_DELEGOK(vp) &&
                            ((nd->nd_flag & ND_NFSV41) == 0 ||
                             (new_stp->ls_flags & NFSLCK_WANTNODELEG) == 0)) {
                                new_deleg->ls_stateid.seqid =
                                    delegstateidp->seqid = 1;
                                new_deleg->ls_stateid.other[0] =
                                    delegstateidp->other[0]
                                    = clp->lc_clientid.lval[0];
                                new_deleg->ls_stateid.other[1] =
                                    delegstateidp->other[1]
                                    = clp->lc_clientid.lval[1];
                                new_deleg->ls_stateid.other[2] =
                                    delegstateidp->other[2]
                                    = nfsrv_nextstateindex(clp);
                                if (writedeleg && !NFSVNO_EXRDONLY(exp) &&
                                    (nfsrv_writedelegifpos || !readonly) &&
                                    ((nd->nd_flag & ND_NFSV41) == 0 ||
                                     (new_stp->ls_flags & NFSLCK_WANTRDELEG) ==
                                     0)) {
                                        new_deleg->ls_flags =
                                            (NFSLCK_DELEGWRITE |
                                             NFSLCK_READACCESS |
                                             NFSLCK_WRITEACCESS);
                                        *rflagsp |= NFSV4OPEN_WRITEDELEGATE;
                                } else {
                                        new_deleg->ls_flags =
                                            (NFSLCK_DELEGREAD |
                                             NFSLCK_READACCESS);
                                        *rflagsp |= NFSV4OPEN_READDELEGATE;
                                }
                                new_deleg->ls_uid = new_stp->ls_uid;
                                new_deleg->ls_lfp = lfp;
                                new_deleg->ls_clp = clp;
                                new_deleg->ls_filerev = filerev;
                                new_deleg->ls_compref = nd->nd_compref;
                                LIST_INSERT_HEAD(&lfp->lf_deleg, new_deleg,
                                    ls_file);
                                LIST_INSERT_HEAD(NFSSTATEHASH(clp,
                                    new_deleg->ls_stateid), new_deleg, ls_hash);
                                LIST_INSERT_HEAD(&clp->lc_deleg, new_deleg,
                                    ls_list);
                                new_deleg = NULL;
                                nfsstatsv1.srvdelegates++;
                                nfsrv_openpluslock++;
                                nfsrv_delegatecnt++;
                        }
                } else {
                        *rflagsp |= NFSV4OPEN_RESULTCONFIRM;
                        new_stp->ls_flags = NFSLCK_NEEDSCONFIRM;
                }
                nfsrvd_refcache(new_stp->ls_op);
                new_stp->ls_noopens = 0;
                LIST_INIT(&new_stp->ls_open);
                LIST_INSERT_HEAD(&new_stp->ls_open, new_open, ls_list);
                LIST_INSERT_HEAD(&clp->lc_open, new_stp, ls_list);
                LIST_INSERT_HEAD(NFSSTATEHASH(clp, new_open->ls_stateid),
                    new_open, ls_hash);
                openstp = new_open;
                new_open = NULL;
                *new_stpp = NULL;
                nfsstatsv1.srvopens++;
                nfsrv_openpluslock++;
                nfsstatsv1.srvopenowners++;
                nfsrv_openpluslock++;
        }
        if (!error) {
                stateidp->seqid = openstp->ls_stateid.seqid;
                stateidp->other[0] = openstp->ls_stateid.other[0];
                stateidp->other[1] = openstp->ls_stateid.other[1];
                stateidp->other[2] = openstp->ls_stateid.other[2];
        }
        NFSUNLOCKSTATE();
        if (haslock) {
                NFSLOCKV4ROOTMUTEX();
                nfsv4_unlock(&nfsv4rootfs_lock, 1);
                NFSUNLOCKV4ROOTMUTEX();
        }
        if (new_open)
                FREE((caddr_t)new_open, M_NFSDSTATE);
        if (new_deleg)
                FREE((caddr_t)new_deleg, M_NFSDSTATE);

out:
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Open update. Does the confirm, downgrade and close.
 */
APPLESTATIC int
nfsrv_openupdate(vnode_t vp, struct nfsstate *new_stp, nfsquad_t clientid,
    nfsv4stateid_t *stateidp, struct nfsrv_descript *nd, NFSPROC_T *p)
{
        struct nfsstate *stp, *ownerstp;
        struct nfsclient *clp;
        struct nfslockfile *lfp;
        u_int32_t bits;
        int error = 0, gotstate = 0, len = 0;
        u_char client[NFSV4_OPAQUELIMIT];

        /*
         * Check for restart conditions (client and server).
         */
        error = nfsrv_checkrestart(clientid, new_stp->ls_flags,
            &new_stp->ls_stateid, 0);
        if (error)
                goto out;

        NFSLOCKSTATE();
        /*
         * Get the open structure via clientid and stateid.
         */
        error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp, NULL,
            (nfsquad_t)((u_quad_t)0), 0, nd, p);
        if (!error)
                error = nfsrv_getstate(clp, &new_stp->ls_stateid,
                    new_stp->ls_flags, &stp);

        /*
         * Sanity check the open.
         */
        if (!error && (!(stp->ls_flags & NFSLCK_OPEN) ||
                (!(new_stp->ls_flags & NFSLCK_CONFIRM) &&
                 (stp->ls_openowner->ls_flags & NFSLCK_NEEDSCONFIRM)) ||
                ((new_stp->ls_flags & NFSLCK_CONFIRM) &&
                 (!(stp->ls_openowner->ls_flags & NFSLCK_NEEDSCONFIRM)))))
                error = NFSERR_BADSTATEID;

        if (!error)
                error = nfsrv_checkseqid(nd, new_stp->ls_seq,
                    stp->ls_openowner, new_stp->ls_op);
        if (!error && stp->ls_stateid.seqid != new_stp->ls_stateid.seqid &&
            (((nd->nd_flag & ND_NFSV41) == 0 &&
              !(new_stp->ls_flags & NFSLCK_CONFIRM)) ||
             ((nd->nd_flag & ND_NFSV41) != 0 &&
              new_stp->ls_stateid.seqid != 0)))
                error = NFSERR_OLDSTATEID;
        if (!error && vnode_vtype(vp) != VREG) {
                if (vnode_vtype(vp) == VDIR)
                        error = NFSERR_ISDIR;
                else
                        error = NFSERR_INVAL;
        }

        if (error) {
                /*
                 * If a client tries to confirm an Open with a bad
                 * seqid# and there are no byte range locks or other Opens
                 * on the openowner, just throw it away, so the next use of the
                 * openowner will start a fresh seq#.
                 */
                if (error == NFSERR_BADSEQID &&
                    (new_stp->ls_flags & NFSLCK_CONFIRM) &&
                    nfsrv_nootherstate(stp))
                        nfsrv_freeopenowner(stp->ls_openowner, 0, p);
                NFSUNLOCKSTATE();
                goto out;
        }

        /*
         * Set the return stateid.
         */
        stateidp->seqid = stp->ls_stateid.seqid + 1;
        if ((nd->nd_flag & ND_NFSV41) != 0 && stateidp->seqid == 0)
                stateidp->seqid = 1;
        stateidp->other[0] = stp->ls_stateid.other[0];
        stateidp->other[1] = stp->ls_stateid.other[1];
        stateidp->other[2] = stp->ls_stateid.other[2];
        /*
         * Now, handle the three cases.
         */
        if (new_stp->ls_flags & NFSLCK_CONFIRM) {
                /*
                 * If the open doesn't need confirmation, it seems to me that
                 * there is a client error, but I'll just log it and keep going?
                 */
                if (!(stp->ls_openowner->ls_flags & NFSLCK_NEEDSCONFIRM))
                        printf("Nfsv4d: stray open confirm\n");
                stp->ls_openowner->ls_flags = 0;
                stp->ls_stateid.seqid++;
                if ((nd->nd_flag & ND_NFSV41) != 0 &&
                    stp->ls_stateid.seqid == 0)
                        stp->ls_stateid.seqid = 1;
                if (!(clp->lc_flags & LCL_STAMPEDSTABLE)) {
                        clp->lc_flags |= LCL_STAMPEDSTABLE;
                        len = clp->lc_idlen;
                        NFSBCOPY(clp->lc_id, client, len);
                        gotstate = 1;
                }
                NFSUNLOCKSTATE();
        } else if (new_stp->ls_flags & NFSLCK_CLOSE) {
                ownerstp = stp->ls_openowner;
                lfp = stp->ls_lfp;
                if (nfsrv_dolocallocks != 0 && !LIST_EMPTY(&stp->ls_open)) {
                        /* Get the lf lock */
                        nfsrv_locklf(lfp);
                        NFSUNLOCKSTATE();
                        ASSERT_VOP_ELOCKED(vp, "nfsrv_openupdate");
                        NFSVOPUNLOCK(vp, 0);
                        if (nfsrv_freeopen(stp, vp, 1, p) == 0) {
                                NFSLOCKSTATE();
                                nfsrv_unlocklf(lfp);
                                NFSUNLOCKSTATE();
                        }
                        NFSVOPLOCK(vp, LK_EXCLUSIVE | LK_RETRY);
                } else {
                        (void) nfsrv_freeopen(stp, NULL, 0, p);
                        NFSUNLOCKSTATE();
                }
        } else {
                /*
                 * Update the share bits, making sure that the new set are a
                 * subset of the old ones.
                 */
                bits = (new_stp->ls_flags & NFSLCK_SHAREBITS);
                if (~(stp->ls_flags) & bits) {
                        NFSUNLOCKSTATE();
                        error = NFSERR_INVAL;
                        goto out;
                }
                stp->ls_flags = (bits | NFSLCK_OPEN);
                stp->ls_stateid.seqid++;
                if ((nd->nd_flag & ND_NFSV41) != 0 &&
                    stp->ls_stateid.seqid == 0)
                        stp->ls_stateid.seqid = 1;
                NFSUNLOCKSTATE();
        }

        /*
         * If the client just confirmed its first open, write a timestamp
         * to the stable storage file.
         */
        if (gotstate != 0) {
                nfsrv_writestable(client, len, NFSNST_NEWSTATE, p);
                nfsrv_backupstable();
        }

out:
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Delegation update. Does the purge and return.
 */
APPLESTATIC int
nfsrv_delegupdate(struct nfsrv_descript *nd, nfsquad_t clientid,
    nfsv4stateid_t *stateidp, vnode_t vp, int op, struct ucred *cred,
    NFSPROC_T *p)
{
        struct nfsstate *stp;
        struct nfsclient *clp;
        int error = 0;
        fhandle_t fh;

        /*
         * Do a sanity check against the file handle for DelegReturn.
         */
        if (vp) {
                error = nfsvno_getfh(vp, &fh, p);
                if (error)
                        goto out;
        }
        /*
         * Check for restart conditions (client and server).
         */
        if (op == NFSV4OP_DELEGRETURN)
                error = nfsrv_checkrestart(clientid, NFSLCK_DELEGRETURN,
                        stateidp, 0);
        else
                error = nfsrv_checkrestart(clientid, NFSLCK_DELEGPURGE,
                        stateidp, 0);

        NFSLOCKSTATE();
        /*
         * Get the open structure via clientid and stateid.
         */
        if (!error)
            error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp, NULL,
                (nfsquad_t)((u_quad_t)0), 0, nd, p);
        if (error) {
                if (error == NFSERR_CBPATHDOWN)
                        error = 0;
                if (error == NFSERR_STALECLIENTID && op == NFSV4OP_DELEGRETURN)
                        error = NFSERR_STALESTATEID;
        }
        if (!error && op == NFSV4OP_DELEGRETURN) {
            error = nfsrv_getstate(clp, stateidp, NFSLCK_DELEGRETURN, &stp);
            if (!error && stp->ls_stateid.seqid != stateidp->seqid &&
                ((nd->nd_flag & ND_NFSV41) == 0 || stateidp->seqid != 0))
                error = NFSERR_OLDSTATEID;
        }
        /*
         * NFSERR_EXPIRED means that the state has gone away,
         * so Delegations have been purged. Just return ok.
         */
        if (error == NFSERR_EXPIRED && op == NFSV4OP_DELEGPURGE) {
                NFSUNLOCKSTATE();
                error = 0;
                goto out;
        }
        if (error) {
                NFSUNLOCKSTATE();
                goto out;
        }

        if (op == NFSV4OP_DELEGRETURN) {
                if (NFSBCMP((caddr_t)&fh, (caddr_t)&stp->ls_lfp->lf_fh,
                    sizeof (fhandle_t))) {
                        NFSUNLOCKSTATE();
                        error = NFSERR_BADSTATEID;
                        goto out;
                }
                nfsrv_freedeleg(stp);
        } else {
                nfsrv_freedeleglist(&clp->lc_olddeleg);
        }
        NFSUNLOCKSTATE();
        error = 0;

out:
        NFSEXITCODE(error);
        return (error);
}

/*
 * Release lock owner.
 */
APPLESTATIC int
nfsrv_releaselckown(struct nfsstate *new_stp, nfsquad_t clientid,
    NFSPROC_T *p)
{
        struct nfsstate *stp, *nstp, *openstp, *ownstp;
        struct nfsclient *clp;
        int error = 0;

        /*
         * Check for restart conditions (client and server).
         */
        error = nfsrv_checkrestart(clientid, new_stp->ls_flags,
            &new_stp->ls_stateid, 0);
        if (error)
                goto out;

        NFSLOCKSTATE();
        /*
         * Get the lock owner by name.
         */
        error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp, NULL,
            (nfsquad_t)((u_quad_t)0), 0, NULL, p);
        if (error) {
                NFSUNLOCKSTATE();
                goto out;
        }
        LIST_FOREACH(ownstp, &clp->lc_open, ls_list) {
            LIST_FOREACH(openstp, &ownstp->ls_open, ls_list) {
                stp = LIST_FIRST(&openstp->ls_open);
                while (stp != NULL) {
                    nstp = LIST_NEXT(stp, ls_list);
                    /*
                     * If the owner matches, check for locks and
                     * then free or return an error.
                     */
                    if (stp->ls_ownerlen == new_stp->ls_ownerlen &&
                        !NFSBCMP(stp->ls_owner, new_stp->ls_owner,
                         stp->ls_ownerlen)){
                        if (LIST_EMPTY(&stp->ls_lock)) {
                            nfsrv_freelockowner(stp, NULL, 0, p);
                        } else {
                            NFSUNLOCKSTATE();
                            error = NFSERR_LOCKSHELD;
                            goto out;
                        }
                    }
                    stp = nstp;
                }
            }
        }
        NFSUNLOCKSTATE();

out:
        NFSEXITCODE(error);
        return (error);
}

/*
 * Get the file handle for a lock structure.
 */
static int
nfsrv_getlockfh(vnode_t vp, u_short flags, struct nfslockfile *new_lfp,
    fhandle_t *nfhp, NFSPROC_T *p)
{
        fhandle_t *fhp = NULL;
        int error;

        /*
         * For lock, use the new nfslock structure, otherwise just
         * a fhandle_t on the stack.
         */
        if (flags & NFSLCK_OPEN) {
                KASSERT(new_lfp != NULL, ("nfsrv_getlockfh: new_lfp NULL"));
                fhp = &new_lfp->lf_fh;
        } else if (nfhp) {
                fhp = nfhp;
        } else {
                panic("nfsrv_getlockfh");
        }
        error = nfsvno_getfh(vp, fhp, p);
        NFSEXITCODE(error);
        return (error);
}

/*
 * Get an nfs lock structure. Allocate one, as required, and return a
 * pointer to it.
 * Returns an NFSERR_xxx upon failure or -1 to indicate no current lock.
 */
static int
nfsrv_getlockfile(u_short flags, struct nfslockfile **new_lfpp,
    struct nfslockfile **lfpp, fhandle_t *nfhp, int lockit)
{
        struct nfslockfile *lfp;
        fhandle_t *fhp = NULL, *tfhp;
        struct nfslockhashhead *hp;
        struct nfslockfile *new_lfp = NULL;

        /*
         * For lock, use the new nfslock structure, otherwise just
         * a fhandle_t on the stack.
         */
        if (flags & NFSLCK_OPEN) {
                new_lfp = *new_lfpp;
                fhp = &new_lfp->lf_fh;
        } else if (nfhp) {
                fhp = nfhp;
        } else {
                panic("nfsrv_getlockfile");
        }

        hp = NFSLOCKHASH(fhp);
        LIST_FOREACH(lfp, hp, lf_hash) {
                tfhp = &lfp->lf_fh;
                if (NFSVNO_CMPFH(fhp, tfhp)) {
                        if (lockit)
                                nfsrv_locklf(lfp);
                        *lfpp = lfp;
                        return (0);
                }
        }
        if (!(flags & NFSLCK_OPEN))
                return (-1);

        /*
         * No match, so chain the new one into the list.
         */
        LIST_INIT(&new_lfp->lf_open);
        LIST_INIT(&new_lfp->lf_lock);
        LIST_INIT(&new_lfp->lf_deleg);
        LIST_INIT(&new_lfp->lf_locallock);
        LIST_INIT(&new_lfp->lf_rollback);
        new_lfp->lf_locallock_lck.nfslock_usecnt = 0;
        new_lfp->lf_locallock_lck.nfslock_lock = 0;
        new_lfp->lf_usecount = 0;
        LIST_INSERT_HEAD(hp, new_lfp, lf_hash);
        *lfpp = new_lfp;
        *new_lfpp = NULL;
        return (0);
}

/*
 * This function adds a nfslock lock structure to the list for the associated
 * nfsstate and nfslockfile structures. It will be inserted after the
 * entry pointed at by insert_lop.
 */
static void
nfsrv_insertlock(struct nfslock *new_lop, struct nfslock *insert_lop,
    struct nfsstate *stp, struct nfslockfile *lfp)
{
        struct nfslock *lop, *nlop;

        new_lop->lo_stp = stp;
        new_lop->lo_lfp = lfp;

        if (stp != NULL) {
                /* Insert in increasing lo_first order */
                lop = LIST_FIRST(&lfp->lf_lock);
                if (lop == NULL ||
                    new_lop->lo_first <= lop->lo_first) {
                        LIST_INSERT_HEAD(&lfp->lf_lock, new_lop, lo_lckfile);
                } else {
                        nlop = LIST_NEXT(lop, lo_lckfile);
                        while (nlop != NULL &&
                               nlop->lo_first < new_lop->lo_first) {
                                lop = nlop;
                                nlop = LIST_NEXT(lop, lo_lckfile);
                        }
                        LIST_INSERT_AFTER(lop, new_lop, lo_lckfile);
                }
        } else {
                new_lop->lo_lckfile.le_prev = NULL;     /* list not used */
        }

        /*
         * Insert after insert_lop, which is overloaded as stp or lfp for
         * an empty list.
         */
        if (stp == NULL && (struct nfslockfile *)insert_lop == lfp)
                LIST_INSERT_HEAD(&lfp->lf_locallock, new_lop, lo_lckowner);
        else if ((struct nfsstate *)insert_lop == stp)
                LIST_INSERT_HEAD(&stp->ls_lock, new_lop, lo_lckowner);
        else
                LIST_INSERT_AFTER(insert_lop, new_lop, lo_lckowner);
        if (stp != NULL) {
                nfsstatsv1.srvlocks++;
                nfsrv_openpluslock++;
        }
}

/*
 * This function updates the locking for a lock owner and given file. It
 * maintains a list of lock ranges ordered on increasing file offset that
 * are NFSLCK_READ or NFSLCK_WRITE and non-overlapping (aka POSIX style).
 * It always adds new_lop to the list and sometimes uses the one pointed
 * at by other_lopp.
 */
static void
nfsrv_updatelock(struct nfsstate *stp, struct nfslock **new_lopp,
    struct nfslock **other_lopp, struct nfslockfile *lfp)
{
        struct nfslock *new_lop = *new_lopp;
        struct nfslock *lop, *tlop, *ilop;
        struct nfslock *other_lop = *other_lopp;
        int unlock = 0, myfile = 0;
        u_int64_t tmp;

        /*
         * Work down the list until the lock is merged.
         */
        if (new_lop->lo_flags & NFSLCK_UNLOCK)
                unlock = 1;
        if (stp != NULL) {
                ilop = (struct nfslock *)stp;
                lop = LIST_FIRST(&stp->ls_lock);
        } else {
                ilop = (struct nfslock *)lfp;
                lop = LIST_FIRST(&lfp->lf_locallock);
        }
        while (lop != NULL) {
            /*
             * Only check locks for this file that aren't before the start of
             * new lock's range.
             */
            if (lop->lo_lfp == lfp) {
              myfile = 1;
              if (lop->lo_end >= new_lop->lo_first) {
                if (new_lop->lo_end < lop->lo_first) {
                        /*
                         * If the new lock ends before the start of the
                         * current lock's range, no merge, just insert
                         * the new lock.
                         */
                        break;
                }
                if (new_lop->lo_flags == lop->lo_flags ||
                    (new_lop->lo_first <= lop->lo_first &&
                     new_lop->lo_end >= lop->lo_end)) {
                        /*
                         * This lock can be absorbed by the new lock/unlock.
                         * This happens when it covers the entire range
                         * of the old lock or is contiguous
                         * with the old lock and is of the same type or an
                         * unlock.
                         */
                        if (lop->lo_first < new_lop->lo_first)
                                new_lop->lo_first = lop->lo_first;
                        if (lop->lo_end > new_lop->lo_end)
                                new_lop->lo_end = lop->lo_end;
                        tlop = lop;
                        lop = LIST_NEXT(lop, lo_lckowner);
                        nfsrv_freenfslock(tlop);
                        continue;
                }

                /*
                 * All these cases are for contiguous locks that are not the
                 * same type, so they can't be merged.
                 */
                if (new_lop->lo_first <= lop->lo_first) {
                        /*
                         * This case is where the new lock overlaps with the
                         * first part of the old lock. Move the start of the
                         * old lock to just past the end of the new lock. The
                         * new lock will be inserted in front of the old, since
                         * ilop hasn't been updated. (We are done now.)
                         */
                        lop->lo_first = new_lop->lo_end;
                        break;
                }
                if (new_lop->lo_end >= lop->lo_end) {
                        /*
                         * This case is where the new lock overlaps with the
                         * end of the old lock's range. Move the old lock's
                         * end to just before the new lock's first and insert
                         * the new lock after the old lock.
                         * Might not be done yet, since the new lock could
                         * overlap further locks with higher ranges.
                         */
                        lop->lo_end = new_lop->lo_first;
                        ilop = lop;
                        lop = LIST_NEXT(lop, lo_lckowner);
                        continue;
                }
                /*
                 * The final case is where the new lock's range is in the
                 * middle of the current lock's and splits the current lock
                 * up. Use *other_lopp to handle the second part of the
                 * split old lock range. (We are done now.)
                 * For unlock, we use new_lop as other_lop and tmp, since
                 * other_lop and new_lop are the same for this case.
                 * We noted the unlock case above, so we don't need
                 * new_lop->lo_flags any longer.
                 */
                tmp = new_lop->lo_first;
                if (other_lop == NULL) {
                        if (!unlock)
                                panic("nfsd srv update unlock");
                        other_lop = new_lop;
                        *new_lopp = NULL;
                }
                other_lop->lo_first = new_lop->lo_end;
                other_lop->lo_end = lop->lo_end;
                other_lop->lo_flags = lop->lo_flags;
                other_lop->lo_stp = stp;
                other_lop->lo_lfp = lfp;
                lop->lo_end = tmp;
                nfsrv_insertlock(other_lop, lop, stp, lfp);
                *other_lopp = NULL;
                ilop = lop;
                break;
              }
            }
            ilop = lop;
            lop = LIST_NEXT(lop, lo_lckowner);
            if (myfile && (lop == NULL || lop->lo_lfp != lfp))
                break;
        }

        /*
         * Insert the new lock in the list at the appropriate place.
         */
        if (!unlock) {
                nfsrv_insertlock(new_lop, ilop, stp, lfp);
                *new_lopp = NULL;
        }
}

/*
 * This function handles sequencing of locks, etc.
 * It returns an error that indicates what the caller should do.
 */
static int
nfsrv_checkseqid(struct nfsrv_descript *nd, u_int32_t seqid,
    struct nfsstate *stp, struct nfsrvcache *op)
{
        int error = 0;

        if ((nd->nd_flag & ND_NFSV41) != 0)
                /* NFSv4.1 ignores the open_seqid and lock_seqid. */
                goto out;
        if (op != nd->nd_rp)
                panic("nfsrvstate checkseqid");
        if (!(op->rc_flag & RC_INPROG))
                panic("nfsrvstate not inprog");
        if (stp->ls_op && stp->ls_op->rc_refcnt <= 0) {
                printf("refcnt=%d\n", stp->ls_op->rc_refcnt);
                panic("nfsrvstate op refcnt");
        }
        if ((stp->ls_seq + 1) == seqid) {
                if (stp->ls_op)
                        nfsrvd_derefcache(stp->ls_op);
                stp->ls_op = op;
                nfsrvd_refcache(op);
                stp->ls_seq = seqid;
                goto out;
        } else if (stp->ls_seq == seqid && stp->ls_op &&
                op->rc_xid == stp->ls_op->rc_xid &&
                op->rc_refcnt == 0 &&
                op->rc_reqlen == stp->ls_op->rc_reqlen &&
                op->rc_cksum == stp->ls_op->rc_cksum) {
                if (stp->ls_op->rc_flag & RC_INPROG) {
                        error = NFSERR_DONTREPLY;
                        goto out;
                }
                nd->nd_rp = stp->ls_op;
                nd->nd_rp->rc_flag |= RC_INPROG;
                nfsrvd_delcache(op);
                error = NFSERR_REPLYFROMCACHE;
                goto out;
        }
        error = NFSERR_BADSEQID;

out:
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Get the client ip address for callbacks. If the strings can't be parsed,
 * just set lc_program to 0 to indicate no callbacks are possible.
 * (For cases where the address can't be parsed or is 0.0.0.0.0.0, set
 *  the address to the client's transport address. This won't be used
 *  for callbacks, but can be printed out by nfsstats for info.)
 * Return error if the xdr can't be parsed, 0 otherwise.
 */
APPLESTATIC int
nfsrv_getclientipaddr(struct nfsrv_descript *nd, struct nfsclient *clp)
{
        u_int32_t *tl;
        u_char *cp, *cp2;
        int i, j;
        struct sockaddr_in *rad, *sad;
        u_char protocol[5], addr[24];
        int error = 0, cantparse = 0;
        union {
                u_long ival;
                u_char cval[4];
        } ip;
        union {
                u_short sval;
                u_char cval[2];
        } port;

        rad = NFSSOCKADDR(clp->lc_req.nr_nam, struct sockaddr_in *);
        rad->sin_family = AF_INET;
        rad->sin_len = sizeof (struct sockaddr_in);
        rad->sin_addr.s_addr = 0;
        rad->sin_port = 0;
        clp->lc_req.nr_client = NULL;
        clp->lc_req.nr_lock = 0;
        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
        i = fxdr_unsigned(int, *tl);
        if (i >= 3 && i <= 4) {
                error = nfsrv_mtostr(nd, protocol, i);
                if (error)
                        goto nfsmout;
                if (!strcmp(protocol, "tcp")) {
                        clp->lc_flags |= LCL_TCPCALLBACK;
                        clp->lc_req.nr_sotype = SOCK_STREAM;
                        clp->lc_req.nr_soproto = IPPROTO_TCP;
                } else if (!strcmp(protocol, "udp")) {
                        clp->lc_req.nr_sotype = SOCK_DGRAM;
                        clp->lc_req.nr_soproto = IPPROTO_UDP;
                } else {
                        cantparse = 1;
                }
        } else {
                cantparse = 1;
                if (i > 0) {
                        error = nfsm_advance(nd, NFSM_RNDUP(i), -1);
                        if (error)
                                goto nfsmout;
                }
        }
        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
        i = fxdr_unsigned(int, *tl);
        if (i < 0) {
                error = NFSERR_BADXDR;
                goto nfsmout;
        } else if (i == 0) {
                cantparse = 1;
        } else if (!cantparse && i <= 23 && i >= 11) {
                error = nfsrv_mtostr(nd, addr, i);
                if (error)
                        goto nfsmout;

                /*
                 * Parse out the address fields. We expect 6 decimal numbers
                 * separated by '.'s.
                 */
                cp = addr;
                i = 0;
                while (*cp && i < 6) {
                        cp2 = cp;
                        while (*cp2 && *cp2 != '.')
                                cp2++;
                        if (*cp2)
                                *cp2++ = '\0';
                        else if (i != 5) {
                                cantparse = 1;
                                break;
                        }
                        j = nfsrv_getipnumber(cp);
                        if (j >= 0) {
                                if (i < 4)
                                        ip.cval[3 - i] = j;
                                else
                                        port.cval[5 - i] = j;
                        } else {
                                cantparse = 1;
                                break;
                        }
                        cp = cp2;
                        i++;
                }
                if (!cantparse) {
                        if (ip.ival != 0x0) {
                                rad->sin_addr.s_addr = htonl(ip.ival);
                                rad->sin_port = htons(port.sval);
                        } else {
                                cantparse = 1;
                        }
                }
        } else {
                cantparse = 1;
                if (i > 0) {
                        error = nfsm_advance(nd, NFSM_RNDUP(i), -1);
                        if (error)
                                goto nfsmout;
                }
        }
        if (cantparse) {
                sad = NFSSOCKADDR(nd->nd_nam, struct sockaddr_in *);
                rad->sin_addr.s_addr = sad->sin_addr.s_addr;
                rad->sin_port = 0x0;
                clp->lc_program = 0;
        }
nfsmout:
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Turn a string of up to three decimal digits into a number. Return -1 upon
 * error.
 */
static int
nfsrv_getipnumber(u_char *cp)
{
        int i = 0, j = 0;

        while (*cp) {
                if (j > 2 || *cp < '0' || *cp > '9')
                        return (-1);
                i *= 10;
                i += (*cp - '0');
                cp++;
                j++;
        }
        if (i < 256)
                return (i);
        return (-1);
}

/*
 * This function checks for restart conditions.
 */
static int
nfsrv_checkrestart(nfsquad_t clientid, u_int32_t flags,
    nfsv4stateid_t *stateidp, int specialid)
{
        int ret = 0;

        /*
         * First check for a server restart. Open, LockT, ReleaseLockOwner
         * and DelegPurge have a clientid, the rest a stateid.
         */
        if (flags &
            (NFSLCK_OPEN | NFSLCK_TEST | NFSLCK_RELEASE | NFSLCK_DELEGPURGE)) {
                if (clientid.lval[0] != nfsrvboottime) {
                        ret = NFSERR_STALECLIENTID;
                        goto out;
                }
        } else if (stateidp->other[0] != nfsrvboottime &&
                specialid == 0) {
                ret = NFSERR_STALESTATEID;
                goto out;
        }

        /*
         * Read, Write, Setattr and LockT can return NFSERR_GRACE and do
         * not use a lock/open owner seqid#, so the check can be done now.
         * (The others will be checked, as required, later.)
         */
        if (!(flags & (NFSLCK_CHECK | NFSLCK_TEST)))
                goto out;

        NFSLOCKSTATE();
        ret = nfsrv_checkgrace(NULL, NULL, flags);
        NFSUNLOCKSTATE();

out:
        NFSEXITCODE(ret);
        return (ret);
}

/*
 * Check for grace.
 */
static int
nfsrv_checkgrace(struct nfsrv_descript *nd, struct nfsclient *clp,
    u_int32_t flags)
{
        int error = 0;

        if ((nfsrv_stablefirst.nsf_flags & NFSNSF_GRACEOVER) != 0) {
                if (flags & NFSLCK_RECLAIM) {
                        error = NFSERR_NOGRACE;
                        goto out;
                }
        } else {
                if (!(flags & NFSLCK_RECLAIM)) {
                        error = NFSERR_GRACE;
                        goto out;
                }
                if (nd != NULL && clp != NULL &&
                    (nd->nd_flag & ND_NFSV41) != 0 &&
                    (clp->lc_flags & LCL_RECLAIMCOMPLETE) != 0) {
                        error = NFSERR_NOGRACE;
                        goto out;
                }

                /*
                 * If grace is almost over and we are still getting Reclaims,
                 * extend grace a bit.
                 */
                if ((NFSD_MONOSEC + NFSRV_LEASEDELTA) >
                    nfsrv_stablefirst.nsf_eograce)
                        nfsrv_stablefirst.nsf_eograce = NFSD_MONOSEC +
                                NFSRV_LEASEDELTA;
        }

out:
        NFSEXITCODE(error);
        return (error);
}

/*
 * Do a server callback.
 */
static int
nfsrv_docallback(struct nfsclient *clp, int procnum,
    nfsv4stateid_t *stateidp, int trunc, fhandle_t *fhp,
    struct nfsvattr *nap, nfsattrbit_t *attrbitp, NFSPROC_T *p)
{
        mbuf_t m;
        u_int32_t *tl;
        struct nfsrv_descript nfsd, *nd = &nfsd;
        struct ucred *cred;
        int error = 0;
        u_int32_t callback;
        struct nfsdsession *sep = NULL;

        cred = newnfs_getcred();
        NFSLOCKSTATE(); /* mostly for lc_cbref++ */
        if (clp->lc_flags & LCL_NEEDSCONFIRM) {
                NFSUNLOCKSTATE();
                panic("docallb");
        }
        clp->lc_cbref++;

        /*
         * Fill the callback program# and version into the request
         * structure for newnfs_connect() to use.
         */
        clp->lc_req.nr_prog = clp->lc_program;
#ifdef notnow
        if ((clp->lc_flags & LCL_NFSV41) != 0)
                clp->lc_req.nr_vers = NFSV41_CBVERS;
        else
#endif
                clp->lc_req.nr_vers = NFSV4_CBVERS;

        /*
         * First, fill in some of the fields of nd and cr.
         */
        nd->nd_flag = ND_NFSV4;
        if (clp->lc_flags & LCL_GSS)
                nd->nd_flag |= ND_KERBV;
        if ((clp->lc_flags & LCL_NFSV41) != 0)
                nd->nd_flag |= ND_NFSV41;
        nd->nd_repstat = 0;
        cred->cr_uid = clp->lc_uid;
        cred->cr_gid = clp->lc_gid;
        callback = clp->lc_callback;
        NFSUNLOCKSTATE();
        cred->cr_ngroups = 1;

        /*
         * Get the first mbuf for the request.
         */
        MGET(m, M_WAITOK, MT_DATA);
        mbuf_setlen(m, 0);
        nd->nd_mreq = nd->nd_mb = m;
        nd->nd_bpos = NFSMTOD(m, caddr_t);
        
        /*
         * and build the callback request.
         */
        if (procnum == NFSV4OP_CBGETATTR) {
                nd->nd_procnum = NFSV4PROC_CBCOMPOUND;
                error = nfsrv_cbcallargs(nd, clp, callback, NFSV4OP_CBGETATTR,
                    "CB Getattr", &sep);
                if (error != 0) {
                        mbuf_freem(nd->nd_mreq);
                        goto errout;
                }
                (void)nfsm_fhtom(nd, (u_int8_t *)fhp, NFSX_MYFH, 0);
                (void)nfsrv_putattrbit(nd, attrbitp);
        } else if (procnum == NFSV4OP_CBRECALL) {
                nd->nd_procnum = NFSV4PROC_CBCOMPOUND;
                error = nfsrv_cbcallargs(nd, clp, callback, NFSV4OP_CBRECALL,
                    "CB Recall", &sep);
                if (error != 0) {
                        mbuf_freem(nd->nd_mreq);
                        goto errout;
                }
                NFSM_BUILD(tl, u_int32_t *, NFSX_UNSIGNED + NFSX_STATEID);
                *tl++ = txdr_unsigned(stateidp->seqid);
                NFSBCOPY((caddr_t)stateidp->other, (caddr_t)tl,
                    NFSX_STATEIDOTHER);
                tl += (NFSX_STATEIDOTHER / NFSX_UNSIGNED);
                if (trunc)
                        *tl = newnfs_true;
                else
                        *tl = newnfs_false;
                (void)nfsm_fhtom(nd, (u_int8_t *)fhp, NFSX_MYFH, 0);
        } else if (procnum == NFSV4PROC_CBNULL) {
                nd->nd_procnum = NFSV4PROC_CBNULL;
                if ((clp->lc_flags & LCL_NFSV41) != 0) {
                        error = nfsv4_getcbsession(clp, &sep);
                        if (error != 0) {
                                mbuf_freem(nd->nd_mreq);
                                goto errout;
                        }
                }
        } else {
                error = NFSERR_SERVERFAULT;
                mbuf_freem(nd->nd_mreq);
                goto errout;
        }

        /*
         * Call newnfs_connect(), as required, and then newnfs_request().
         */
        (void) newnfs_sndlock(&clp->lc_req.nr_lock);
        if (clp->lc_req.nr_client == NULL) {
                if ((clp->lc_flags & LCL_NFSV41) != 0)
                        error = ECONNREFUSED;
                else if (nd->nd_procnum == NFSV4PROC_CBNULL)
                        error = newnfs_connect(NULL, &clp->lc_req, cred,
                            NULL, 1);
                else
                        error = newnfs_connect(NULL, &clp->lc_req, cred,
                            NULL, 3);
        }
        newnfs_sndunlock(&clp->lc_req.nr_lock);
        if (!error) {
                if ((nd->nd_flag & ND_NFSV41) != 0) {
                        KASSERT(sep != NULL, ("sep NULL"));
                        if (sep->sess_cbsess.nfsess_xprt != NULL)
                                error = newnfs_request(nd, NULL, clp,
                                    &clp->lc_req, NULL, NULL, cred,
                                    clp->lc_program, clp->lc_req.nr_vers, NULL,
                                    1, NULL, &sep->sess_cbsess);
                        else {
                                /*
                                 * This should probably never occur, but if a
                                 * client somehow does an RPC without a
                                 * SequenceID Op that causes a callback just
                                 * after the nfsd threads have been terminated
                                 * and restarted we could conceivably get here
                                 * without a backchannel xprt.
                                 */
                                printf("nfsrv_docallback: no xprt\n");
                                error = ECONNREFUSED;
                        }
                        nfsrv_freesession(sep, NULL);
                } else
                        error = newnfs_request(nd, NULL, clp, &clp->lc_req,
                            NULL, NULL, cred, clp->lc_program,
                            clp->lc_req.nr_vers, NULL, 1, NULL, NULL);
        }
errout:
        NFSFREECRED(cred);

        /*
         * If error is set here, the Callback path isn't working
         * properly, so twiddle the appropriate LCL_ flags.
         * (nd_repstat != 0 indicates the Callback path is working,
         *  but the callback failed on the client.)
         */
        if (error) {
                /*
                 * Mark the callback pathway down, which disabled issuing
                 * of delegations and gets Renew to return NFSERR_CBPATHDOWN.
                 */
                NFSLOCKSTATE();
                clp->lc_flags |= LCL_CBDOWN;
                NFSUNLOCKSTATE();
        } else {
                /*
                 * Callback worked. If the callback path was down, disable
                 * callbacks, so no more delegations will be issued. (This
                 * is done on the assumption that the callback pathway is
                 * flakey.)
                 */
                NFSLOCKSTATE();
                if (clp->lc_flags & LCL_CBDOWN)
                        clp->lc_flags &= ~(LCL_CBDOWN | LCL_CALLBACKSON);
                NFSUNLOCKSTATE();
                if (nd->nd_repstat)
                        error = nd->nd_repstat;
                else if (error == 0 && procnum == NFSV4OP_CBGETATTR)
                        error = nfsv4_loadattr(nd, NULL, nap, NULL, NULL, 0,
                            NULL, NULL, NULL, NULL, NULL, 0, NULL, NULL, NULL,
                            p, NULL);
                mbuf_freem(nd->nd_mrep);
        }
        NFSLOCKSTATE();
        clp->lc_cbref--;
        if ((clp->lc_flags & LCL_WAKEUPWANTED) && clp->lc_cbref == 0) {
                clp->lc_flags &= ~LCL_WAKEUPWANTED;
                wakeup(clp);
        }
        NFSUNLOCKSTATE();

        NFSEXITCODE(error);
        return (error);
}

/*
 * Set up the compound RPC for the callback.
 */
static int
nfsrv_cbcallargs(struct nfsrv_descript *nd, struct nfsclient *clp,
    uint32_t callback, int op, const char *optag, struct nfsdsession **sepp)
{
        uint32_t *tl;
        int error, len;

        len = strlen(optag);
        (void)nfsm_strtom(nd, optag, len);
        NFSM_BUILD(tl, uint32_t *, 4 * NFSX_UNSIGNED);
        if ((nd->nd_flag & ND_NFSV41) != 0) {
                *tl++ = txdr_unsigned(NFSV41_MINORVERSION);
                *tl++ = txdr_unsigned(callback);
                *tl++ = txdr_unsigned(2);
                *tl = txdr_unsigned(NFSV4OP_CBSEQUENCE);
                error = nfsv4_setcbsequence(nd, clp, 1, sepp);
                if (error != 0)
                        return (error);
                NFSM_BUILD(tl, u_int32_t *, NFSX_UNSIGNED);
                *tl = txdr_unsigned(op);
        } else {
                *tl++ = txdr_unsigned(NFSV4_MINORVERSION);
                *tl++ = txdr_unsigned(callback);
                *tl++ = txdr_unsigned(1);
                *tl = txdr_unsigned(op);
        }
        return (0);
}

/*
 * Return the next index# for a clientid. Mostly just increment and return
 * the next one, but... if the 32bit unsigned does actually wrap around,
 * it should be rebooted.
 * At an average rate of one new client per second, it will wrap around in
 * approximately 136 years. (I think the server will have been shut
 * down or rebooted before then.)
 */
static u_int32_t
nfsrv_nextclientindex(void)
{
        static u_int32_t client_index = 0;

        client_index++;
        if (client_index != 0)
                return (client_index);

        printf("%s: out of clientids\n", __func__);
        return (client_index);
}

/*
 * Return the next index# for a stateid. Mostly just increment and return
 * the next one, but... if the 32bit unsigned does actually wrap around
 * (will a BSD server stay up that long?), find
 * new start and end values.
 */
static u_int32_t
nfsrv_nextstateindex(struct nfsclient *clp)
{
        struct nfsstate *stp;
        int i;
        u_int32_t canuse, min_index, max_index;

        if (!(clp->lc_flags & LCL_INDEXNOTOK)) {
                clp->lc_stateindex++;
                if (clp->lc_stateindex != clp->lc_statemaxindex)
                        return (clp->lc_stateindex);
        }

        /*
         * Yuck, we've hit the end.
         * Look for a new min and max.
         */
        min_index = 0;
        max_index = 0xffffffff;
        for (i = 0; i < nfsrv_statehashsize; i++) {
            LIST_FOREACH(stp, &clp->lc_stateid[i], ls_hash) {
                if (stp->ls_stateid.other[2] > 0x80000000) {
                    if (stp->ls_stateid.other[2] < max_index)
                        max_index = stp->ls_stateid.other[2];
                } else {
                    if (stp->ls_stateid.other[2] > min_index)
                        min_index = stp->ls_stateid.other[2];
                }
            }
        }

        /*
         * Yikes, highly unlikely, but I'll handle it anyhow.
         */
        if (min_index == 0x80000000 && max_index == 0x80000001) {
            canuse = 0;
            /*
             * Loop around until we find an unused entry. Return that
             * and set LCL_INDEXNOTOK, so the search will continue next time.
             * (This is one of those rare cases where a goto is the
             *  cleanest way to code the loop.)
             */
tryagain:
            for (i = 0; i < nfsrv_statehashsize; i++) {
                LIST_FOREACH(stp, &clp->lc_stateid[i], ls_hash) {
                    if (stp->ls_stateid.other[2] == canuse) {
                        canuse++;
                        goto tryagain;
                    }
                }
            }
            clp->lc_flags |= LCL_INDEXNOTOK;
            return (canuse);
        }

        /*
         * Ok to start again from min + 1.
         */
        clp->lc_stateindex = min_index + 1;
        clp->lc_statemaxindex = max_index;
        clp->lc_flags &= ~LCL_INDEXNOTOK;
        return (clp->lc_stateindex);
}

/*
 * The following functions handle the stable storage file that deals with
 * the edge conditions described in RFC3530 Sec. 8.6.3.
 * The file is as follows:
 * - a single record at the beginning that has the lease time of the
 *   previous server instance (before the last reboot) and the nfsrvboottime
 *   values for the previous server boots.
 *   These previous boot times are used to ensure that the current
 *   nfsrvboottime does not, somehow, get set to a previous one.
 *   (This is important so that Stale ClientIDs and StateIDs can
 *    be recognized.)
 *   The number of previous nfsvrboottime values precedes the list.
 * - followed by some number of appended records with:
 *   - client id string
 *   - flag that indicates it is a record revoking state via lease
 *     expiration or similar
 *     OR has successfully acquired state.
 * These structures vary in length, with the client string at the end, up
 * to NFSV4_OPAQUELIMIT in size.
 *
 * At the end of the grace period, the file is truncated, the first
 * record is rewritten with updated information and any acquired state
 * records for successful reclaims of state are written.
 *
 * Subsequent records are appended when the first state is issued to
 * a client and when state is revoked for a client.
 *
 * When reading the file in, state issued records that come later in
 * the file override older ones, since the append log is in cronological order.
 * If, for some reason, the file can't be read, the grace period is
 * immediately terminated and all reclaims get NFSERR_NOGRACE.
 */

/*
 * Read in the stable storage file. Called by nfssvc() before the nfsd
 * processes start servicing requests.
 */
APPLESTATIC void
nfsrv_setupstable(NFSPROC_T *p)
{
        struct nfsrv_stablefirst *sf = &nfsrv_stablefirst;
        struct nfsrv_stable *sp, *nsp;
        struct nfst_rec *tsp;
        int error, i, tryagain;
        off_t off = 0;
        ssize_t aresid, len;

        /*
         * If NFSNSF_UPDATEDONE is set, this is a restart of the nfsds without
         * a reboot, so state has not been lost.
         */
        if (sf->nsf_flags & NFSNSF_UPDATEDONE)
                return;
        /*
         * Set Grace over just until the file reads successfully.
         */
        nfsrvboottime = time_second;
        LIST_INIT(&sf->nsf_head);
        sf->nsf_flags = (NFSNSF_GRACEOVER | NFSNSF_NEEDLOCK);
        sf->nsf_eograce = NFSD_MONOSEC + NFSRV_LEASEDELTA;
        if (sf->nsf_fp == NULL)
                return;
        error = NFSD_RDWR(UIO_READ, NFSFPVNODE(sf->nsf_fp),
            (caddr_t)&sf->nsf_rec, sizeof (struct nfsf_rec), off, UIO_SYSSPACE,
            0, NFSFPCRED(sf->nsf_fp), &aresid, p);
        if (error || aresid || sf->nsf_numboots == 0 ||
                sf->nsf_numboots > NFSNSF_MAXNUMBOOTS)
                return;

        /*
         * Now, read in the boottimes.
         */
        sf->nsf_bootvals = (time_t *)malloc((sf->nsf_numboots + 1) *
                sizeof (time_t), M_TEMP, M_WAITOK);
        off = sizeof (struct nfsf_rec);
        error = NFSD_RDWR(UIO_READ, NFSFPVNODE(sf->nsf_fp),
            (caddr_t)sf->nsf_bootvals, sf->nsf_numboots * sizeof (time_t), off,
            UIO_SYSSPACE, 0, NFSFPCRED(sf->nsf_fp), &aresid, p);
        if (error || aresid) {
                free((caddr_t)sf->nsf_bootvals, M_TEMP);
                sf->nsf_bootvals = NULL;
                return;
        }

        /*
         * Make sure this nfsrvboottime is different from all recorded
         * previous ones.
         */
        do {
                tryagain = 0;
                for (i = 0; i < sf->nsf_numboots; i++) {
                        if (nfsrvboottime == sf->nsf_bootvals[i]) {
                                nfsrvboottime++;
                                tryagain = 1;
                                break;
                        }
                }
        } while (tryagain);

        sf->nsf_flags |= NFSNSF_OK;
        off += (sf->nsf_numboots * sizeof (time_t));

        /*
         * Read through the file, building a list of records for grace
         * checking.
         * Each record is between sizeof (struct nfst_rec) and
         * sizeof (struct nfst_rec) + NFSV4_OPAQUELIMIT - 1
         * and is actually sizeof (struct nfst_rec) + nst_len - 1.
         */
        tsp = (struct nfst_rec *)malloc(sizeof (struct nfst_rec) +
                NFSV4_OPAQUELIMIT - 1, M_TEMP, M_WAITOK);
        do {
            error = NFSD_RDWR(UIO_READ, NFSFPVNODE(sf->nsf_fp),
                (caddr_t)tsp, sizeof (struct nfst_rec) + NFSV4_OPAQUELIMIT - 1,
                off, UIO_SYSSPACE, 0, NFSFPCRED(sf->nsf_fp), &aresid, p);
            len = (sizeof (struct nfst_rec) + NFSV4_OPAQUELIMIT - 1) - aresid;
            if (error || (len > 0 && (len < sizeof (struct nfst_rec) ||
                len < (sizeof (struct nfst_rec) + tsp->len - 1)))) {
                /*
                 * Yuck, the file has been corrupted, so just return
                 * after clearing out any restart state, so the grace period
                 * is over.
                 */
                LIST_FOREACH_SAFE(sp, &sf->nsf_head, nst_list, nsp) {
                        LIST_REMOVE(sp, nst_list);
                        free((caddr_t)sp, M_TEMP);
                }
                free((caddr_t)tsp, M_TEMP);
                sf->nsf_flags &= ~NFSNSF_OK;
                free((caddr_t)sf->nsf_bootvals, M_TEMP);
                sf->nsf_bootvals = NULL;
                return;
            }
            if (len > 0) {
                off += sizeof (struct nfst_rec) + tsp->len - 1;
                /*
                 * Search the list for a matching client.
                 */
                LIST_FOREACH(sp, &sf->nsf_head, nst_list) {
                        if (tsp->len == sp->nst_len &&
                            !NFSBCMP(tsp->client, sp->nst_client, tsp->len))
                                break;
                }
                if (sp == NULL) {
                        sp = (struct nfsrv_stable *)malloc(tsp->len +
                                sizeof (struct nfsrv_stable) - 1, M_TEMP,
                                M_WAITOK);
                        NFSBCOPY((caddr_t)tsp, (caddr_t)&sp->nst_rec,
                                sizeof (struct nfst_rec) + tsp->len - 1);
                        LIST_INSERT_HEAD(&sf->nsf_head, sp, nst_list);
                } else {
                        if (tsp->flag == NFSNST_REVOKE)
                                sp->nst_flag |= NFSNST_REVOKE;
                        else
                                /*
                                 * A subsequent timestamp indicates the client
                                 * did a setclientid/confirm and any previous
                                 * revoke is no longer relevant.
                                 */
                                sp->nst_flag &= ~NFSNST_REVOKE;
                }
            }
        } while (len > 0);
        free((caddr_t)tsp, M_TEMP);
        sf->nsf_flags = NFSNSF_OK;
        sf->nsf_eograce = NFSD_MONOSEC + sf->nsf_lease +
                NFSRV_LEASEDELTA;
}

/*
 * Update the stable storage file, now that the grace period is over.
 */
APPLESTATIC void
nfsrv_updatestable(NFSPROC_T *p)
{
        struct nfsrv_stablefirst *sf = &nfsrv_stablefirst;
        struct nfsrv_stable *sp, *nsp;
        int i;
        struct nfsvattr nva;
        vnode_t vp;
#if defined(__FreeBSD_version) && (__FreeBSD_version >= 500000)
        mount_t mp = NULL;
#endif
        int error;

        if (sf->nsf_fp == NULL || (sf->nsf_flags & NFSNSF_UPDATEDONE))
                return;
        sf->nsf_flags |= NFSNSF_UPDATEDONE;
        /*
         * Ok, we need to rewrite the stable storage file.
         * - truncate to 0 length
         * - write the new first structure
         * - loop through the data structures, writing out any that
         *   have timestamps older than the old boot
         */
        if (sf->nsf_bootvals) {
                sf->nsf_numboots++;
                for (i = sf->nsf_numboots - 2; i >= 0; i--)
                        sf->nsf_bootvals[i + 1] = sf->nsf_bootvals[i];
        } else {
                sf->nsf_numboots = 1;
                sf->nsf_bootvals = (time_t *)malloc(sizeof (time_t),
                        M_TEMP, M_WAITOK);
        }
        sf->nsf_bootvals[0] = nfsrvboottime;
        sf->nsf_lease = nfsrv_lease;
        NFSVNO_ATTRINIT(&nva);
        NFSVNO_SETATTRVAL(&nva, size, 0);
        vp = NFSFPVNODE(sf->nsf_fp);
        vn_start_write(vp, &mp, V_WAIT);
        if (NFSVOPLOCK(vp, LK_EXCLUSIVE) == 0) {
                error = nfsvno_setattr(vp, &nva, NFSFPCRED(sf->nsf_fp), p,
                    NULL);
                NFSVOPUNLOCK(vp, 0);
        } else
                error = EPERM;
        vn_finished_write(mp);
        if (!error)
            error = NFSD_RDWR(UIO_WRITE, vp,
                (caddr_t)&sf->nsf_rec, sizeof (struct nfsf_rec), (off_t)0,
                UIO_SYSSPACE, IO_SYNC, NFSFPCRED(sf->nsf_fp), NULL, p);
        if (!error)
            error = NFSD_RDWR(UIO_WRITE, vp,
                (caddr_t)sf->nsf_bootvals,
                sf->nsf_numboots * sizeof (time_t),
                (off_t)(sizeof (struct nfsf_rec)),
                UIO_SYSSPACE, IO_SYNC, NFSFPCRED(sf->nsf_fp), NULL, p);
        free((caddr_t)sf->nsf_bootvals, M_TEMP);
        sf->nsf_bootvals = NULL;
        if (error) {
                sf->nsf_flags &= ~NFSNSF_OK;
                printf("EEK! Can't write NfsV4 stable storage file\n");
                return;
        }
        sf->nsf_flags |= NFSNSF_OK;

        /*
         * Loop through the list and write out timestamp records for
         * any clients that successfully reclaimed state.
         */
        LIST_FOREACH_SAFE(sp, &sf->nsf_head, nst_list, nsp) {
                if (sp->nst_flag & NFSNST_GOTSTATE) {
                        nfsrv_writestable(sp->nst_client, sp->nst_len,
                                NFSNST_NEWSTATE, p);
                        sp->nst_clp->lc_flags |= LCL_STAMPEDSTABLE;
                }
                LIST_REMOVE(sp, nst_list);
                free((caddr_t)sp, M_TEMP);
        }
        nfsrv_backupstable();
}

/*
 * Append a record to the stable storage file.
 */
APPLESTATIC void
nfsrv_writestable(u_char *client, int len, int flag, NFSPROC_T *p)
{
        struct nfsrv_stablefirst *sf = &nfsrv_stablefirst;
        struct nfst_rec *sp;
        int error;

        if (!(sf->nsf_flags & NFSNSF_OK) || sf->nsf_fp == NULL)
                return;
        sp = (struct nfst_rec *)malloc(sizeof (struct nfst_rec) +
                len - 1, M_TEMP, M_WAITOK);
        sp->len = len;
        NFSBCOPY(client, sp->client, len);
        sp->flag = flag;
        error = NFSD_RDWR(UIO_WRITE, NFSFPVNODE(sf->nsf_fp),
            (caddr_t)sp, sizeof (struct nfst_rec) + len - 1, (off_t)0,
            UIO_SYSSPACE, (IO_SYNC | IO_APPEND), NFSFPCRED(sf->nsf_fp), NULL, p);
        free((caddr_t)sp, M_TEMP);
        if (error) {
                sf->nsf_flags &= ~NFSNSF_OK;
                printf("EEK! Can't write NfsV4 stable storage file\n");
        }
}

/*
 * This function is called during the grace period to mark a client
 * that successfully reclaimed state.
 */
static void
nfsrv_markstable(struct nfsclient *clp)
{
        struct nfsrv_stable *sp;

        /*
         * First find the client structure.
         */
        LIST_FOREACH(sp, &nfsrv_stablefirst.nsf_head, nst_list) {
                if (sp->nst_len == clp->lc_idlen &&
                    !NFSBCMP(sp->nst_client, clp->lc_id, sp->nst_len))
                        break;
        }
        if (sp == NULL)
                return;

        /*
         * Now, just mark it and set the nfsclient back pointer.
         */
        sp->nst_flag |= NFSNST_GOTSTATE;
        sp->nst_clp = clp;
}

/*
 * This function is called for a reclaim, to see if it gets grace.
 * It returns 0 if a reclaim is allowed, 1 otherwise.
 */
static int
nfsrv_checkstable(struct nfsclient *clp)
{
        struct nfsrv_stable *sp;

        /*
         * First, find the entry for the client.
         */
        LIST_FOREACH(sp, &nfsrv_stablefirst.nsf_head, nst_list) {
                if (sp->nst_len == clp->lc_idlen &&
                    !NFSBCMP(sp->nst_client, clp->lc_id, sp->nst_len))
                        break;
        }

        /*
         * If not in the list, state was revoked or no state was issued
         * since the previous reboot, a reclaim is denied.
         */
        if (sp == NULL ||
            (sp->nst_flag & NFSNST_REVOKE) ||
            !(nfsrv_stablefirst.nsf_flags & NFSNSF_OK))
                return (1);
        return (0);
}

/*
 * Test for and try to clear out a conflicting client. This is called by
 * nfsrv_lockctrl() and nfsrv_openctrl() when conflicts with other clients
 * a found.
 * The trick here is that it can't revoke a conflicting client with an
 * expired lease unless it holds the v4root lock, so...
 * If no v4root lock, get the lock and return 1 to indicate "try again".
 * Return 0 to indicate the conflict can't be revoked and 1 to indicate
 * the revocation worked and the conflicting client is "bye, bye", so it
 * can be tried again.
 * Return 2 to indicate that the vnode is VI_DOOMED after NFSVOPLOCK().
 * Unlocks State before a non-zero value is returned.
 */
static int
nfsrv_clientconflict(struct nfsclient *clp, int *haslockp, vnode_t vp,
    NFSPROC_T *p)
{
        int gotlock, lktype = 0;

        /*
         * If lease hasn't expired, we can't fix it.
         */
        if (clp->lc_expiry >= NFSD_MONOSEC ||
            !(nfsrv_stablefirst.nsf_flags & NFSNSF_UPDATEDONE))
                return (0);
        if (*haslockp == 0) {
                NFSUNLOCKSTATE();
                if (vp != NULL) {
                        lktype = NFSVOPISLOCKED(vp);
                        NFSVOPUNLOCK(vp, 0);
                }
                NFSLOCKV4ROOTMUTEX();
                nfsv4_relref(&nfsv4rootfs_lock);
                do {
                        gotlock = nfsv4_lock(&nfsv4rootfs_lock, 1, NULL,
                            NFSV4ROOTLOCKMUTEXPTR, NULL);
                } while (!gotlock);
                NFSUNLOCKV4ROOTMUTEX();
                *haslockp = 1;
                if (vp != NULL) {
                        NFSVOPLOCK(vp, lktype | LK_RETRY);
                        if ((vp->v_iflag & VI_DOOMED) != 0)
                                return (2);
                }
                return (1);
        }
        NFSUNLOCKSTATE();

        /*
         * Ok, we can expire the conflicting client.
         */
        nfsrv_writestable(clp->lc_id, clp->lc_idlen, NFSNST_REVOKE, p);
        nfsrv_backupstable();
        nfsrv_cleanclient(clp, p);
        nfsrv_freedeleglist(&clp->lc_deleg);
        nfsrv_freedeleglist(&clp->lc_olddeleg);
        LIST_REMOVE(clp, lc_hash);
        nfsrv_zapclient(clp, p);
        return (1);
}

/*
 * Resolve a delegation conflict.
 * Returns 0 to indicate the conflict was resolved without sleeping.
 * Return -1 to indicate that the caller should check for conflicts again.
 * Return > 0 for an error that should be returned, normally NFSERR_DELAY.
 *
 * Also, manipulate the nfsv4root_lock, as required. It isn't changed
 * for a return of 0, since there was no sleep and it could be required
 * later. It is released for a return of NFSERR_DELAY, since the caller
 * will return that error. It is released when a sleep was done waiting
 * for the delegation to be returned or expire (so that other nfsds can
 * handle ops). Then, it must be acquired for the write to stable storage.
 * (This function is somewhat similar to nfsrv_clientconflict(), but
 *  the semantics differ in a couple of subtle ways. The return of 0
 *  indicates the conflict was resolved without sleeping here, not
 *  that the conflict can't be resolved and the handling of nfsv4root_lock
 *  differs, as noted above.)
 * Unlocks State before returning a non-zero value.
 */
static int
nfsrv_delegconflict(struct nfsstate *stp, int *haslockp, NFSPROC_T *p,
    vnode_t vp)
{
        struct nfsclient *clp = stp->ls_clp;
        int gotlock, error, lktype = 0, retrycnt, zapped_clp;
        nfsv4stateid_t tstateid;
        fhandle_t tfh;

        /*
         * If the conflict is with an old delegation...
         */
        if (stp->ls_flags & NFSLCK_OLDDELEG) {
                /*
                 * You can delete it, if it has expired.
                 */
                if (clp->lc_delegtime < NFSD_MONOSEC) {
                        nfsrv_freedeleg(stp);
                        NFSUNLOCKSTATE();
                        error = -1;
                        goto out;
                }
                NFSUNLOCKSTATE();
                /*
                 * During this delay, the old delegation could expire or it
                 * could be recovered by the client via an Open with
                 * CLAIM_DELEGATE_PREV.
                 * Release the nfsv4root_lock, if held.
                 */
                if (*haslockp) {
                        *haslockp = 0;
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                }
                error = NFSERR_DELAY;
                goto out;
        }

        /*
         * It's a current delegation, so:
         * - check to see if the delegation has expired
         *   - if so, get the v4root lock and then expire it
         */
        if (!(stp->ls_flags & NFSLCK_DELEGRECALL)) {
                /*
                 * - do a recall callback, since not yet done
                 * For now, never allow truncate to be set. To use
                 * truncate safely, it must be guaranteed that the
                 * Remove, Rename or Setattr with size of 0 will
                 * succeed and that would require major changes to
                 * the VFS/Vnode OPs.
                 * Set the expiry time large enough so that it won't expire
                 * until after the callback, then set it correctly, once
                 * the callback is done. (The delegation will now time
                 * out whether or not the Recall worked ok. The timeout
                 * will be extended when ops are done on the delegation
                 * stateid, up to the timelimit.)
                 */
                stp->ls_delegtime = NFSD_MONOSEC + (2 * nfsrv_lease) +
                    NFSRV_LEASEDELTA;
                stp->ls_delegtimelimit = NFSD_MONOSEC + (6 * nfsrv_lease) +
                    NFSRV_LEASEDELTA;
                stp->ls_flags |= NFSLCK_DELEGRECALL;

                /*
                 * Loop NFSRV_CBRETRYCNT times while the CBRecall replies
                 * NFSERR_BADSTATEID or NFSERR_BADHANDLE. This is done
                 * in order to try and avoid a race that could happen
                 * when a CBRecall request passed the Open reply with
                 * the delegation in it when transitting the network.
                 * Since nfsrv_docallback will sleep, don't use stp after
                 * the call.
                 */
                NFSBCOPY((caddr_t)&stp->ls_stateid, (caddr_t)&tstateid,
                    sizeof (tstateid));
                NFSBCOPY((caddr_t)&stp->ls_lfp->lf_fh, (caddr_t)&tfh,
                    sizeof (tfh));
                NFSUNLOCKSTATE();
                if (*haslockp) {
                        *haslockp = 0;
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                }
                retrycnt = 0;
                do {
                    error = nfsrv_docallback(clp, NFSV4OP_CBRECALL,
                        &tstateid, 0, &tfh, NULL, NULL, p);
                    retrycnt++;
                } while ((error == NFSERR_BADSTATEID ||
                    error == NFSERR_BADHANDLE) && retrycnt < NFSV4_CBRETRYCNT);
                error = NFSERR_DELAY;
                goto out;
        }

        if (clp->lc_expiry >= NFSD_MONOSEC &&
            stp->ls_delegtime >= NFSD_MONOSEC) {
                NFSUNLOCKSTATE();
                /*
                 * A recall has been done, but it has not yet expired.
                 * So, RETURN_DELAY.
                 */
                if (*haslockp) {
                        *haslockp = 0;
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                }
                error = NFSERR_DELAY;
                goto out;
        }

        /*
         * If we don't yet have the lock, just get it and then return,
         * since we need that before deleting expired state, such as
         * this delegation.
         * When getting the lock, unlock the vnode, so other nfsds that
         * are in progress, won't get stuck waiting for the vnode lock.
         */
        if (*haslockp == 0) {
                NFSUNLOCKSTATE();
                if (vp != NULL) {
                        lktype = NFSVOPISLOCKED(vp);
                        NFSVOPUNLOCK(vp, 0);
                }
                NFSLOCKV4ROOTMUTEX();
                nfsv4_relref(&nfsv4rootfs_lock);
                do {
                        gotlock = nfsv4_lock(&nfsv4rootfs_lock, 1, NULL,
                            NFSV4ROOTLOCKMUTEXPTR, NULL);
                } while (!gotlock);
                NFSUNLOCKV4ROOTMUTEX();
                *haslockp = 1;
                if (vp != NULL) {
                        NFSVOPLOCK(vp, lktype | LK_RETRY);
                        if ((vp->v_iflag & VI_DOOMED) != 0) {
                                *haslockp = 0;
                                NFSLOCKV4ROOTMUTEX();
                                nfsv4_unlock(&nfsv4rootfs_lock, 1);
                                NFSUNLOCKV4ROOTMUTEX();
                                error = NFSERR_PERM;
                                goto out;
                        }
                }
                error = -1;
                goto out;
        }

        NFSUNLOCKSTATE();
        /*
         * Ok, we can delete the expired delegation.
         * First, write the Revoke record to stable storage and then
         * clear out the conflict.
         * Since all other nfsd threads are now blocked, we can safely
         * sleep without the state changing.
         */
        nfsrv_writestable(clp->lc_id, clp->lc_idlen, NFSNST_REVOKE, p);
        nfsrv_backupstable();
        if (clp->lc_expiry < NFSD_MONOSEC) {
                nfsrv_cleanclient(clp, p);
                nfsrv_freedeleglist(&clp->lc_deleg);
                nfsrv_freedeleglist(&clp->lc_olddeleg);
                LIST_REMOVE(clp, lc_hash);
                zapped_clp = 1;
        } else {
                nfsrv_freedeleg(stp);
                zapped_clp = 0;
        }
        if (zapped_clp)
                nfsrv_zapclient(clp, p);
        error = -1;

out:
        NFSEXITCODE(error);
        return (error);
}

/*
 * Check for a remove allowed, if remove is set to 1 and get rid of
 * delegations.
 */
APPLESTATIC int
nfsrv_checkremove(vnode_t vp, int remove, NFSPROC_T *p)
{
        struct nfsstate *stp;
        struct nfslockfile *lfp;
        int error, haslock = 0;
        fhandle_t nfh;

        /*
         * First, get the lock file structure.
         * (A return of -1 means no associated state, so remove ok.)
         */
        error = nfsrv_getlockfh(vp, NFSLCK_CHECK, NULL, &nfh, p);
tryagain:
        NFSLOCKSTATE();
        if (!error)
                error = nfsrv_getlockfile(NFSLCK_CHECK, NULL, &lfp, &nfh, 0);
        if (error) {
                NFSUNLOCKSTATE();
                if (haslock) {
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                }
                if (error == -1)
                        error = 0;
                goto out;
        }

        /*
         * Now, we must Recall any delegations.
         */
        error = nfsrv_cleandeleg(vp, lfp, NULL, &haslock, p);
        if (error) {
                /*
                 * nfsrv_cleandeleg() unlocks state for non-zero
                 * return.
                 */
                if (error == -1)
                        goto tryagain;
                if (haslock) {
                        NFSLOCKV4ROOTMUTEX();
                        nfsv4_unlock(&nfsv4rootfs_lock, 1);
                        NFSUNLOCKV4ROOTMUTEX();
                }
                goto out;
        }

        /*
         * Now, look for a conflicting open share.
         */
        if (remove) {
                /*
                 * If the entry in the directory was the last reference to the
                 * corresponding filesystem object, the object can be destroyed
                 * */
                if(lfp->lf_usecount>1)
                        LIST_FOREACH(stp, &lfp->lf_open, ls_file) {
                                if (stp->ls_flags & NFSLCK_WRITEDENY) {
                                        error = NFSERR_FILEOPEN;
                                        break;
                                }
                        }
        }

        NFSUNLOCKSTATE();
        if (haslock) {
                NFSLOCKV4ROOTMUTEX();
                nfsv4_unlock(&nfsv4rootfs_lock, 1);
                NFSUNLOCKV4ROOTMUTEX();
        }

out:
        NFSEXITCODE(error);
        return (error);
}

/*
 * Clear out all delegations for the file referred to by lfp.
 * May return NFSERR_DELAY, if there will be a delay waiting for
 * delegations to expire.
 * Returns -1 to indicate it slept while recalling a delegation.
 * This function has the side effect of deleting the nfslockfile structure,
 * if it no longer has associated state and didn't have to sleep.
 * Unlocks State before a non-zero value is returned.
 */
static int
nfsrv_cleandeleg(vnode_t vp, struct nfslockfile *lfp,
    struct nfsclient *clp, int *haslockp, NFSPROC_T *p)
{
        struct nfsstate *stp, *nstp;
        int ret = 0;

        stp = LIST_FIRST(&lfp->lf_deleg);
        while (stp != NULL) {
                nstp = LIST_NEXT(stp, ls_file);
                if (stp->ls_clp != clp) {
                        ret = nfsrv_delegconflict(stp, haslockp, p, vp);
                        if (ret) {
                                /*
                                 * nfsrv_delegconflict() unlocks state
                                 * when it returns non-zero.
                                 */
                                goto out;
                        }
                }
                stp = nstp;
        }
out:
        NFSEXITCODE(ret);
        return (ret);
}

/*
 * There are certain operations that, when being done outside of NFSv4,
 * require that any NFSv4 delegation for the file be recalled.
 * This function is to be called for those cases:
 * VOP_RENAME() - When a delegation is being recalled for any reason,
 *      the client may have to do Opens against the server, using the file's
 *      final component name. If the file has been renamed on the server,
 *      that component name will be incorrect and the Open will fail.
 * VOP_REMOVE() - Theoretically, a client could Open a file after it has
 *      been removed on the server, if there is a delegation issued to
 *      that client for the file. I say "theoretically" since clients
 *      normally do an Access Op before the Open and that Access Op will
 *      fail with ESTALE. Note that NFSv2 and 3 don't even do Opens, so
 *      they will detect the file's removal in the same manner. (There is
 *      one case where RFC3530 allows a client to do an Open without first
 *      doing an Access Op, which is passage of a check against the ACE
 *      returned with a Write delegation, but current practice is to ignore
 *      the ACE and always do an Access Op.)
 *      Since the functions can only be called with an unlocked vnode, this
 *      can't be done at this time.
 * VOP_ADVLOCK() - When a client holds a delegation, it can issue byte range
 *      locks locally in the client, which are not visible to the server. To
 *      deal with this, issuing of delegations for a vnode must be disabled
 *      and all delegations for the vnode recalled. This is done via the
 *      second function, using the VV_DISABLEDELEG vflag on the vnode.
 */
APPLESTATIC void
nfsd_recalldelegation(vnode_t vp, NFSPROC_T *p)
{
        time_t starttime;
        int error;

        /*
         * First, check to see if the server is currently running and it has
         * been called for a regular file when issuing delegations.
         */
        if (newnfs_numnfsd == 0 || vp->v_type != VREG ||
            nfsrv_issuedelegs == 0)
                return;

        KASSERT((NFSVOPISLOCKED(vp) != LK_EXCLUSIVE), ("vp %p is locked", vp));
        /*
         * First, get a reference on the nfsv4rootfs_lock so that an
         * exclusive lock cannot be acquired by another thread.
         */
        NFSLOCKV4ROOTMUTEX();
        nfsv4_getref(&nfsv4rootfs_lock, NULL, NFSV4ROOTLOCKMUTEXPTR, NULL);
        NFSUNLOCKV4ROOTMUTEX();

        /*
         * Now, call nfsrv_checkremove() in a loop while it returns
         * NFSERR_DELAY. Return upon any other error or when timed out.
         */
        starttime = NFSD_MONOSEC;
        do {
                if (NFSVOPLOCK(vp, LK_EXCLUSIVE) == 0) {
                        error = nfsrv_checkremove(vp, 0, p);
                        NFSVOPUNLOCK(vp, 0);
                } else
                        error = EPERM;
                if (error == NFSERR_DELAY) {
                        if (NFSD_MONOSEC - starttime > NFS_REMOVETIMEO)
                                break;
                        /* Sleep for a short period of time */
                        (void) nfs_catnap(PZERO, 0, "nfsremove");
                }
        } while (error == NFSERR_DELAY);
        NFSLOCKV4ROOTMUTEX();
        nfsv4_relref(&nfsv4rootfs_lock);
        NFSUNLOCKV4ROOTMUTEX();
}

APPLESTATIC void
nfsd_disabledelegation(vnode_t vp, NFSPROC_T *p)
{

#ifdef VV_DISABLEDELEG
        /*
         * First, flag issuance of delegations disabled.
         */
        atomic_set_long(&vp->v_vflag, VV_DISABLEDELEG);
#endif

        /*
         * Then call nfsd_recalldelegation() to get rid of all extant
         * delegations.
         */
        nfsd_recalldelegation(vp, p);
}

/*
 * Check for conflicting locks, etc. and then get rid of delegations.
 * (At one point I thought that I should get rid of delegations for any
 *  Setattr, since it could potentially disallow the I/O op (read or write)
 *  allowed by the delegation. However, Setattr Ops that aren't changing
 *  the size get a stateid of all 0s, so you can't tell if it is a delegation
 *  for the same client or a different one, so I decided to only get rid
 *  of delegations for other clients when the size is being changed.)
 * In general, a Setattr can disable NFS I/O Ops that are outstanding, such
 * as Write backs, even if there is no delegation, so it really isn't any
 * different?)
 */
APPLESTATIC int
nfsrv_checksetattr(vnode_t vp, struct nfsrv_descript *nd,
    nfsv4stateid_t *stateidp, struct nfsvattr *nvap, nfsattrbit_t *attrbitp,
    struct nfsexstuff *exp, NFSPROC_T *p)
{
        struct nfsstate st, *stp = &st;
        struct nfslock lo, *lop = &lo;
        int error = 0;
        nfsquad_t clientid;

        if (NFSISSET_ATTRBIT(attrbitp, NFSATTRBIT_SIZE)) {
                stp->ls_flags = (NFSLCK_CHECK | NFSLCK_WRITEACCESS);
                lop->lo_first = nvap->na_size;
        } else {
                stp->ls_flags = 0;
                lop->lo_first = 0;
        }
        if (NFSISSET_ATTRBIT(attrbitp, NFSATTRBIT_OWNER) ||
            NFSISSET_ATTRBIT(attrbitp, NFSATTRBIT_OWNERGROUP) ||
            NFSISSET_ATTRBIT(attrbitp, NFSATTRBIT_MODE) ||
            NFSISSET_ATTRBIT(attrbitp, NFSATTRBIT_ACL))
                stp->ls_flags |= NFSLCK_SETATTR;
        if (stp->ls_flags == 0)
                goto out;
        lop->lo_end = NFS64BITSSET;
        lop->lo_flags = NFSLCK_WRITE;
        stp->ls_ownerlen = 0;
        stp->ls_op = NULL;
        stp->ls_uid = nd->nd_cred->cr_uid;
        stp->ls_stateid.seqid = stateidp->seqid;
        clientid.lval[0] = stp->ls_stateid.other[0] = stateidp->other[0];
        clientid.lval[1] = stp->ls_stateid.other[1] = stateidp->other[1];
        stp->ls_stateid.other[2] = stateidp->other[2];
        error = nfsrv_lockctrl(vp, &stp, &lop, NULL, clientid,
            stateidp, exp, nd, p);

out:
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Check for a write delegation and do a CBGETATTR if there is one, updating
 * the attributes, as required.
 * Should I return an error if I can't get the attributes? (For now, I'll
 * just return ok.
 */
APPLESTATIC int
nfsrv_checkgetattr(struct nfsrv_descript *nd, vnode_t vp,
    struct nfsvattr *nvap, nfsattrbit_t *attrbitp, struct ucred *cred,
    NFSPROC_T *p)
{
        struct nfsstate *stp;
        struct nfslockfile *lfp;
        struct nfsclient *clp;
        struct nfsvattr nva;
        fhandle_t nfh;
        int error = 0;
        nfsattrbit_t cbbits;
        u_quad_t delegfilerev;

        NFSCBGETATTR_ATTRBIT(attrbitp, &cbbits);
        if (!NFSNONZERO_ATTRBIT(&cbbits))
                goto out;

        /*
         * Get the lock file structure.
         * (A return of -1 means no associated state, so return ok.)
         */
        error = nfsrv_getlockfh(vp, NFSLCK_CHECK, NULL, &nfh, p);
        NFSLOCKSTATE();
        if (!error)
                error = nfsrv_getlockfile(NFSLCK_CHECK, NULL, &lfp, &nfh, 0);
        if (error) {
                NFSUNLOCKSTATE();
                if (error == -1)
                        error = 0;
                goto out;
        }

        /*
         * Now, look for a write delegation.
         */
        LIST_FOREACH(stp, &lfp->lf_deleg, ls_file) {
                if (stp->ls_flags & NFSLCK_DELEGWRITE)
                        break;
        }
        if (stp == NULL) {
                NFSUNLOCKSTATE();
                goto out;
        }
        clp = stp->ls_clp;
        delegfilerev = stp->ls_filerev;

        /*
         * If the Write delegation was issued as a part of this Compound RPC
         * or if we have an Implied Clientid (used in a previous Op in this
         * compound) and it is the client the delegation was issued to,
         * just return ok.
         * I also assume that it is from the same client iff the network
         * host IP address is the same as the callback address. (Not
         * exactly correct by the RFC, but avoids a lot of Getattr
         * callbacks.)
         */
        if (nd->nd_compref == stp->ls_compref ||
            ((nd->nd_flag & ND_IMPLIEDCLID) &&
             clp->lc_clientid.qval == nd->nd_clientid.qval) ||
             nfsaddr2_match(clp->lc_req.nr_nam, nd->nd_nam)) {
                NFSUNLOCKSTATE();
                goto out;
        }

        /*
         * We are now done with the delegation state structure,
         * so the statelock can be released and we can now tsleep().
         */

        /*
         * Now, we must do the CB Getattr callback, to see if Change or Size
         * has changed.
         */
        if (clp->lc_expiry >= NFSD_MONOSEC) {
                NFSUNLOCKSTATE();
                NFSVNO_ATTRINIT(&nva);
                nva.na_filerev = NFS64BITSSET;
                error = nfsrv_docallback(clp, NFSV4OP_CBGETATTR, NULL,
                    0, &nfh, &nva, &cbbits, p);
                if (!error) {
                        if ((nva.na_filerev != NFS64BITSSET &&
                            nva.na_filerev > delegfilerev) ||
                            (NFSVNO_ISSETSIZE(&nva) &&
                             nva.na_size != nvap->na_size)) {
                                error = nfsvno_updfilerev(vp, nvap, cred, p);
                                if (NFSVNO_ISSETSIZE(&nva))
                                        nvap->na_size = nva.na_size;
                        }
                } else
                        error = 0;      /* Ignore callback errors for now. */
        } else {
                NFSUNLOCKSTATE();
        }

out:
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * This function looks for openowners that haven't had any opens for
 * a while and throws them away. Called by an nfsd when NFSNSF_NOOPENS
 * is set.
 */
APPLESTATIC void
nfsrv_throwawayopens(NFSPROC_T *p)
{
        struct nfsclient *clp, *nclp;
        struct nfsstate *stp, *nstp;
        int i;

        NFSLOCKSTATE();
        nfsrv_stablefirst.nsf_flags &= ~NFSNSF_NOOPENS;
        /*
         * For each client...
         */
        for (i = 0; i < nfsrv_clienthashsize; i++) {
            LIST_FOREACH_SAFE(clp, &nfsclienthash[i], lc_hash, nclp) {
                LIST_FOREACH_SAFE(stp, &clp->lc_open, ls_list, nstp) {
                        if (LIST_EMPTY(&stp->ls_open) &&
                            (stp->ls_noopens > NFSNOOPEN ||
                             (nfsrv_openpluslock * 2) >
                             nfsrv_v4statelimit))
                                nfsrv_freeopenowner(stp, 0, p);
                }
            }
        }
        NFSUNLOCKSTATE();
}

/*
 * This function checks to see if the credentials are the same.
 * Returns 1 for not same, 0 otherwise.
 */
static int
nfsrv_notsamecredname(struct nfsrv_descript *nd, struct nfsclient *clp)
{

        if (nd->nd_flag & ND_GSS) {
                if (!(clp->lc_flags & LCL_GSS))
                        return (1);
                if (clp->lc_flags & LCL_NAME) {
                        if (nd->nd_princlen != clp->lc_namelen ||
                            NFSBCMP(nd->nd_principal, clp->lc_name,
                                clp->lc_namelen))
                                return (1);
                        else
                                return (0);
                }
                if (nd->nd_cred->cr_uid == clp->lc_uid)
                        return (0);
                else
                        return (1);
        } else if (clp->lc_flags & LCL_GSS)
                return (1);
        /*
         * For AUTH_SYS, allow the same uid or root. (This is underspecified
         * in RFC3530, which talks about principals, but doesn't say anything
         * about uids for AUTH_SYS.)
         */
        if (nd->nd_cred->cr_uid == clp->lc_uid || nd->nd_cred->cr_uid == 0)
                return (0);
        else
                return (1);
}

/*
 * Calculate the lease expiry time.
 */
static time_t
nfsrv_leaseexpiry(void)
{

        if (nfsrv_stablefirst.nsf_eograce > NFSD_MONOSEC)
                return (NFSD_MONOSEC + 2 * (nfsrv_lease + NFSRV_LEASEDELTA));
        return (NFSD_MONOSEC + nfsrv_lease + NFSRV_LEASEDELTA);
}

/*
 * Delay the delegation timeout as far as ls_delegtimelimit, as required.
 */
static void
nfsrv_delaydelegtimeout(struct nfsstate *stp)
{

        if ((stp->ls_flags & NFSLCK_DELEGRECALL) == 0)
                return;

        if ((stp->ls_delegtime + 15) > NFSD_MONOSEC &&
            stp->ls_delegtime < stp->ls_delegtimelimit) {
                stp->ls_delegtime += nfsrv_lease;
                if (stp->ls_delegtime > stp->ls_delegtimelimit)
                        stp->ls_delegtime = stp->ls_delegtimelimit;
        }
}

/*
 * This function checks to see if there is any other state associated
 * with the openowner for this Open.
 * It returns 1 if there is no other state, 0 otherwise.
 */
static int
nfsrv_nootherstate(struct nfsstate *stp)
{
        struct nfsstate *tstp;

        LIST_FOREACH(tstp, &stp->ls_openowner->ls_open, ls_list) {
                if (tstp != stp || !LIST_EMPTY(&tstp->ls_lock))
                        return (0);
        }
        return (1);
}

/*
 * Create a list of lock deltas (changes to local byte range locking
 * that can be rolled back using the list) and apply the changes via
 * nfsvno_advlock(). Optionally, lock the list. It is expected that either
 * the rollback or update function will be called after this.
 * It returns an error (and rolls back, as required), if any nfsvno_advlock()
 * call fails. If it returns an error, it will unlock the list.
 */
static int
nfsrv_locallock(vnode_t vp, struct nfslockfile *lfp, int flags,
    uint64_t first, uint64_t end, struct nfslockconflict *cfp, NFSPROC_T *p)
{
        struct nfslock *lop, *nlop;
        int error = 0;

        /* Loop through the list of locks. */
        lop = LIST_FIRST(&lfp->lf_locallock);
        while (first < end && lop != NULL) {
                nlop = LIST_NEXT(lop, lo_lckowner);
                if (first >= lop->lo_end) {
                        /* not there yet */
                        lop = nlop;
                } else if (first < lop->lo_first) {
                        /* new one starts before entry in list */
                        if (end <= lop->lo_first) {
                                /* no overlap between old and new */
                                error = nfsrv_dolocal(vp, lfp, flags,
                                    NFSLCK_UNLOCK, first, end, cfp, p);
                                if (error != 0)
                                        break;
                                first = end;
                        } else {
                                /* handle fragment overlapped with new one */
                                error = nfsrv_dolocal(vp, lfp, flags,
                                    NFSLCK_UNLOCK, first, lop->lo_first, cfp,
                                    p);
                                if (error != 0)
                                        break;
                                first = lop->lo_first;
                        }
                } else {
                        /* new one overlaps this entry in list */
                        if (end <= lop->lo_end) {
                                /* overlaps all of new one */
                                error = nfsrv_dolocal(vp, lfp, flags,
                                    lop->lo_flags, first, end, cfp, p);
                                if (error != 0)
                                        break;
                                first = end;
                        } else {
                                /* handle fragment overlapped with new one */
                                error = nfsrv_dolocal(vp, lfp, flags,
                                    lop->lo_flags, first, lop->lo_end, cfp, p);
                                if (error != 0)
                                        break;
                                first = lop->lo_end;
                                lop = nlop;
                        }
                }
        }
        if (first < end && error == 0)
                /* handle fragment past end of list */
                error = nfsrv_dolocal(vp, lfp, flags, NFSLCK_UNLOCK, first,
                    end, cfp, p);

        NFSEXITCODE(error);
        return (error);
}

/*
 * Local lock unlock. Unlock all byte ranges that are no longer locked
 * by NFSv4. To do this, unlock any subranges of first-->end that
 * do not overlap with the byte ranges of any lock in the lfp->lf_lock
 * list. This list has all locks for the file held by other
 * <clientid, lockowner> tuples. The list is ordered by increasing
 * lo_first value, but may have entries that overlap each other, for
 * the case of read locks.
 */
static void
nfsrv_localunlock(vnode_t vp, struct nfslockfile *lfp, uint64_t init_first,
    uint64_t init_end, NFSPROC_T *p)
{
        struct nfslock *lop;
        uint64_t first, end, prevfirst;

        first = init_first;
        end = init_end;
        while (first < init_end) {
                /* Loop through all nfs locks, adjusting first and end */
                prevfirst = 0;
                LIST_FOREACH(lop, &lfp->lf_lock, lo_lckfile) {
                        KASSERT(prevfirst <= lop->lo_first,
                            ("nfsv4 locks out of order"));
                        KASSERT(lop->lo_first < lop->lo_end,
                            ("nfsv4 bogus lock"));
                        prevfirst = lop->lo_first;
                        if (first >= lop->lo_first &&
                            first < lop->lo_end)
                                /*
                                 * Overlaps with initial part, so trim
                                 * off that initial part by moving first past
                                 * it.
                                 */
                                first = lop->lo_end;
                        else if (end > lop->lo_first &&
                            lop->lo_first > first) {
                                /*
                                 * This lock defines the end of the
                                 * segment to unlock, so set end to the
                                 * start of it and break out of the loop.
                                 */
                                end = lop->lo_first;
                                break;
                        }
                        if (first >= end)
                                /*
                                 * There is no segment left to do, so
                                 * break out of this loop and then exit
                                 * the outer while() since first will be set
                                 * to end, which must equal init_end here.
                                 */
                                break;
                }
                if (first < end) {
                        /* Unlock this segment */
                        (void) nfsrv_dolocal(vp, lfp, NFSLCK_UNLOCK,
                            NFSLCK_READ, first, end, NULL, p);
                        nfsrv_locallock_commit(lfp, NFSLCK_UNLOCK,
                            first, end);
                }
                /*
                 * Now move past this segment and look for any further
                 * segment in the range, if there is one.
                 */
                first = end;
                end = init_end;
        }
}

/*
 * Do the local lock operation and update the rollback list, as required.
 * Perform the rollback and return the error if nfsvno_advlock() fails.
 */
static int
nfsrv_dolocal(vnode_t vp, struct nfslockfile *lfp, int flags, int oldflags,
    uint64_t first, uint64_t end, struct nfslockconflict *cfp, NFSPROC_T *p)
{
        struct nfsrollback *rlp;
        int error = 0, ltype, oldltype;

        if (flags & NFSLCK_WRITE)
                ltype = F_WRLCK;
        else if (flags & NFSLCK_READ)
                ltype = F_RDLCK;
        else
                ltype = F_UNLCK;
        if (oldflags & NFSLCK_WRITE)
                oldltype = F_WRLCK;
        else if (oldflags & NFSLCK_READ)
                oldltype = F_RDLCK;
        else
                oldltype = F_UNLCK;
        if (ltype == oldltype || (oldltype == F_WRLCK && ltype == F_RDLCK))
                /* nothing to do */
                goto out;
        error = nfsvno_advlock(vp, ltype, first, end, p);
        if (error != 0) {
                if (cfp != NULL) {
                        cfp->cl_clientid.lval[0] = 0;
                        cfp->cl_clientid.lval[1] = 0;
                        cfp->cl_first = 0;
                        cfp->cl_end = NFS64BITSSET;
                        cfp->cl_flags = NFSLCK_WRITE;
                        cfp->cl_ownerlen = 5;
                        NFSBCOPY("LOCAL", cfp->cl_owner, 5);
                }
                nfsrv_locallock_rollback(vp, lfp, p);
        } else if (ltype != F_UNLCK) {
                rlp = malloc(sizeof (struct nfsrollback), M_NFSDROLLBACK,
                    M_WAITOK);
                rlp->rlck_first = first;
                rlp->rlck_end = end;
                rlp->rlck_type = oldltype;
                LIST_INSERT_HEAD(&lfp->lf_rollback, rlp, rlck_list);
        }

out:
        NFSEXITCODE(error);
        return (error);
}

/*
 * Roll back local lock changes and free up the rollback list.
 */
static void
nfsrv_locallock_rollback(vnode_t vp, struct nfslockfile *lfp, NFSPROC_T *p)
{
        struct nfsrollback *rlp, *nrlp;

        LIST_FOREACH_SAFE(rlp, &lfp->lf_rollback, rlck_list, nrlp) {
                (void) nfsvno_advlock(vp, rlp->rlck_type, rlp->rlck_first,
                    rlp->rlck_end, p);
                free(rlp, M_NFSDROLLBACK);
        }
        LIST_INIT(&lfp->lf_rollback);
}

/*
 * Update local lock list and delete rollback list (ie now committed to the
 * local locks). Most of the work is done by the internal function.
 */
static void
nfsrv_locallock_commit(struct nfslockfile *lfp, int flags, uint64_t first,
    uint64_t end)
{
        struct nfsrollback *rlp, *nrlp;
        struct nfslock *new_lop, *other_lop;

        new_lop = malloc(sizeof (struct nfslock), M_NFSDLOCK, M_WAITOK);
        if (flags & (NFSLCK_READ | NFSLCK_WRITE))
                other_lop = malloc(sizeof (struct nfslock), M_NFSDLOCK,
                    M_WAITOK);
        else
                other_lop = NULL;
        new_lop->lo_flags = flags;
        new_lop->lo_first = first;
        new_lop->lo_end = end;
        nfsrv_updatelock(NULL, &new_lop, &other_lop, lfp);
        if (new_lop != NULL)
                free(new_lop, M_NFSDLOCK);
        if (other_lop != NULL)
                free(other_lop, M_NFSDLOCK);

        /* and get rid of the rollback list */
        LIST_FOREACH_SAFE(rlp, &lfp->lf_rollback, rlck_list, nrlp)
                free(rlp, M_NFSDROLLBACK);
        LIST_INIT(&lfp->lf_rollback);
}

/*
 * Lock the struct nfslockfile for local lock updating.
 */
static void
nfsrv_locklf(struct nfslockfile *lfp)
{
        int gotlock;

        /* lf_usecount ensures *lfp won't be free'd */
        lfp->lf_usecount++;
        do {
                gotlock = nfsv4_lock(&lfp->lf_locallock_lck, 1, NULL,
                    NFSSTATEMUTEXPTR, NULL);
        } while (gotlock == 0);
        lfp->lf_usecount--;
}

/*
 * Unlock the struct nfslockfile after local lock updating.
 */
static void
nfsrv_unlocklf(struct nfslockfile *lfp)
{

        nfsv4_unlock(&lfp->lf_locallock_lck, 0);
}

/*
 * Clear out all state for the NFSv4 server.
 * Must be called by a thread that can sleep when no nfsds are running.
 */
void
nfsrv_throwawayallstate(NFSPROC_T *p)
{
        struct nfsclient *clp, *nclp;
        struct nfslockfile *lfp, *nlfp;
        int i;

        /*
         * For each client, clean out the state and then free the structure.
         */
        for (i = 0; i < nfsrv_clienthashsize; i++) {
                LIST_FOREACH_SAFE(clp, &nfsclienthash[i], lc_hash, nclp) {
                        nfsrv_cleanclient(clp, p);
                        nfsrv_freedeleglist(&clp->lc_deleg);
                        nfsrv_freedeleglist(&clp->lc_olddeleg);
                        free(clp->lc_stateid, M_NFSDCLIENT);
                        free(clp, M_NFSDCLIENT);
                }
        }

        /*
         * Also, free up any remaining lock file structures.
         */
        for (i = 0; i < nfsrv_lockhashsize; i++) {
                LIST_FOREACH_SAFE(lfp, &nfslockhash[i], lf_hash, nlfp) {
                        printf("nfsd unload: fnd a lock file struct\n");
                        nfsrv_freenfslockfile(lfp);
                }
        }
}

/*
 * Check the sequence# for the session and slot provided as an argument.
 * Also, renew the lease if the session will return NFS_OK.
 */
int
nfsrv_checksequence(struct nfsrv_descript *nd, uint32_t sequenceid,
    uint32_t *highest_slotidp, uint32_t *target_highest_slotidp, int cache_this,
    uint32_t *sflagsp, NFSPROC_T *p)
{
        struct nfsdsession *sep;
        struct nfssessionhash *shp;
        int error;
        SVCXPRT *savxprt;

        shp = NFSSESSIONHASH(nd->nd_sessionid);
        NFSLOCKSESSION(shp);
        sep = nfsrv_findsession(nd->nd_sessionid);
        if (sep == NULL) {
                NFSUNLOCKSESSION(shp);
                return (NFSERR_BADSESSION);
        }
        error = nfsv4_seqsession(sequenceid, nd->nd_slotid, *highest_slotidp,
            sep->sess_slots, NULL, NFSV4_SLOTS - 1);
        if (error != 0) {
                NFSUNLOCKSESSION(shp);
                return (error);
        }
        if (cache_this != 0)
                nd->nd_flag |= ND_SAVEREPLY;
        /* Renew the lease. */
        sep->sess_clp->lc_expiry = nfsrv_leaseexpiry();
        nd->nd_clientid.qval = sep->sess_clp->lc_clientid.qval;
        nd->nd_flag |= ND_IMPLIEDCLID;

        /*
         * If this session handles the backchannel, save the nd_xprt for this
         * RPC, since this is the one being used.
         */
        if (sep->sess_clp->lc_req.nr_client != NULL &&
            (sep->sess_crflags & NFSV4CRSESS_CONNBACKCHAN) != 0) {
                savxprt = sep->sess_cbsess.nfsess_xprt;
                SVC_ACQUIRE(nd->nd_xprt);
                nd->nd_xprt->xp_p2 =
                    sep->sess_clp->lc_req.nr_client->cl_private;
                nd->nd_xprt->xp_idletimeout = 0;        /* Disable timeout. */
                sep->sess_cbsess.nfsess_xprt = nd->nd_xprt;
                if (savxprt != NULL)
                        SVC_RELEASE(savxprt);
        }

        *sflagsp = 0;
        if (sep->sess_clp->lc_req.nr_client == NULL)
                *sflagsp |= NFSV4SEQ_CBPATHDOWN;
        NFSUNLOCKSESSION(shp);
        if (error == NFSERR_EXPIRED) {
                *sflagsp |= NFSV4SEQ_EXPIREDALLSTATEREVOKED;
                error = 0;
        } else if (error == NFSERR_ADMINREVOKED) {
                *sflagsp |= NFSV4SEQ_ADMINSTATEREVOKED;
                error = 0;
        }
        *highest_slotidp = *target_highest_slotidp = NFSV4_SLOTS - 1;
        return (0);
}

/*
 * Check/set reclaim complete for this session/clientid.
 */
int
nfsrv_checkreclaimcomplete(struct nfsrv_descript *nd)
{
        struct nfsdsession *sep;
        struct nfssessionhash *shp;
        int error = 0;

        shp = NFSSESSIONHASH(nd->nd_sessionid);
        NFSLOCKSTATE();
        NFSLOCKSESSION(shp);
        sep = nfsrv_findsession(nd->nd_sessionid);
        if (sep == NULL) {
                NFSUNLOCKSESSION(shp);
                NFSUNLOCKSTATE();
                return (NFSERR_BADSESSION);
        }

        /* Check to see if reclaim complete has already happened. */
        if ((sep->sess_clp->lc_flags & LCL_RECLAIMCOMPLETE) != 0)
                error = NFSERR_COMPLETEALREADY;
        else
                sep->sess_clp->lc_flags |= LCL_RECLAIMCOMPLETE;
        NFSUNLOCKSESSION(shp);
        NFSUNLOCKSTATE();
        return (error);
}

/*
 * Cache the reply in a session slot.
 */
void
nfsrv_cache_session(uint8_t *sessionid, uint32_t slotid, int repstat,
   struct mbuf **m)
{
        struct nfsdsession *sep;
        struct nfssessionhash *shp;

        shp = NFSSESSIONHASH(sessionid);
        NFSLOCKSESSION(shp);
        sep = nfsrv_findsession(sessionid);
        if (sep == NULL) {
                NFSUNLOCKSESSION(shp);
                printf("nfsrv_cache_session: no session\n");
                m_freem(*m);
                return;
        }
        nfsv4_seqsess_cacherep(slotid, sep->sess_slots, repstat, m);
        NFSUNLOCKSESSION(shp);
}

/*
 * Search for a session that matches the sessionid.
 */
static struct nfsdsession *
nfsrv_findsession(uint8_t *sessionid)
{
        struct nfsdsession *sep;
        struct nfssessionhash *shp;

        shp = NFSSESSIONHASH(sessionid);
        LIST_FOREACH(sep, &shp->list, sess_hash) {
                if (!NFSBCMP(sessionid, sep->sess_sessionid, NFSX_V4SESSIONID))
                        break;
        }
        return (sep);
}

/*
 * Destroy a session.
 */
int
nfsrv_destroysession(struct nfsrv_descript *nd, uint8_t *sessionid)
{
        int error, samesess;

        samesess = 0;
        if (!NFSBCMP(sessionid, nd->nd_sessionid, NFSX_V4SESSIONID)) {
                samesess = 1;
                if ((nd->nd_flag & ND_LASTOP) == 0)
                        return (NFSERR_BADSESSION);
        }
        error = nfsrv_freesession(NULL, sessionid);
        if (error == 0 && samesess != 0)
                nd->nd_flag &= ~ND_HASSEQUENCE;
        return (error);
}

/*
 * Free up a session structure.
 */
static int
nfsrv_freesession(struct nfsdsession *sep, uint8_t *sessionid)
{
        struct nfssessionhash *shp;
        int i;

        NFSLOCKSTATE();
        if (sep == NULL) {
                shp = NFSSESSIONHASH(sessionid);
                NFSLOCKSESSION(shp);
                sep = nfsrv_findsession(sessionid);
        } else {
                shp = NFSSESSIONHASH(sep->sess_sessionid);
                NFSLOCKSESSION(shp);
        }
        if (sep != NULL) {
                sep->sess_refcnt--;
                if (sep->sess_refcnt > 0) {
                        NFSUNLOCKSESSION(shp);
                        NFSUNLOCKSTATE();
                        return (0);
                }
                LIST_REMOVE(sep, sess_hash);
                LIST_REMOVE(sep, sess_list);
        }
        NFSUNLOCKSESSION(shp);
        NFSUNLOCKSTATE();
        if (sep == NULL)
                return (NFSERR_BADSESSION);
        for (i = 0; i < NFSV4_SLOTS; i++)
                m_freem(sep->sess_slots[i].nfssl_reply);
        if (sep->sess_cbsess.nfsess_xprt != NULL)
                SVC_RELEASE(sep->sess_cbsess.nfsess_xprt);
        free(sep, M_NFSDSESSION);
        return (0);
}

/*
 * Free a stateid.
 * RFC5661 says that it should fail when there are associated opens, locks
 * or delegations. Since stateids represent opens, I don't see how you can
 * free an open stateid (it will be free'd when closed), so this function
 * only works for lock stateids (freeing the lock_owner) or delegations.
 */
int
nfsrv_freestateid(struct nfsrv_descript *nd, nfsv4stateid_t *stateidp,
    NFSPROC_T *p)
{
        struct nfsclient *clp;
        struct nfsstate *stp;
        int error;

        NFSLOCKSTATE();
        /*
         * Look up the stateid
         */
        error = nfsrv_getclient((nfsquad_t)((u_quad_t)0), CLOPS_RENEW, &clp,
            NULL, (nfsquad_t)((u_quad_t)0), 0, nd, p);
        if (error == 0) {
                /* First, check for a delegation. */
                LIST_FOREACH(stp, &clp->lc_deleg, ls_list) {
                        if (!NFSBCMP(stp->ls_stateid.other, stateidp->other,
                            NFSX_STATEIDOTHER))
                                break;
                }
                if (stp != NULL) {
                        nfsrv_freedeleg(stp);
                        NFSUNLOCKSTATE();
                        return (error);
                }
        }
        /* Not a delegation, try for a lock_owner. */
        if (error == 0)
                error = nfsrv_getstate(clp, stateidp, 0, &stp);
        if (error == 0 && ((stp->ls_flags & (NFSLCK_OPEN | NFSLCK_DELEGREAD |
            NFSLCK_DELEGWRITE)) != 0 || (stp->ls_flags & NFSLCK_LOCK) == 0))
                /* Not a lock_owner stateid. */
                error = NFSERR_LOCKSHELD;
        if (error == 0 && !LIST_EMPTY(&stp->ls_lock))
                error = NFSERR_LOCKSHELD;
        if (error == 0)
                nfsrv_freelockowner(stp, NULL, 0, p);
        NFSUNLOCKSTATE();
        return (error);
}

/*
 * Generate the xdr for an NFSv4.1 CBSequence Operation.
 */
static int
nfsv4_setcbsequence(struct nfsrv_descript *nd, struct nfsclient *clp,
    int dont_replycache, struct nfsdsession **sepp)
{
        struct nfsdsession *sep;
        uint32_t *tl, slotseq = 0;
        int maxslot, slotpos;
        uint8_t sessionid[NFSX_V4SESSIONID];
        int error;

        error = nfsv4_getcbsession(clp, sepp);
        if (error != 0)
                return (error);
        sep = *sepp;
        (void)nfsv4_sequencelookup(NULL, &sep->sess_cbsess, &slotpos, &maxslot,
            &slotseq, sessionid);
        KASSERT(maxslot >= 0, ("nfsv4_setcbsequence neg maxslot"));

        /* Build the Sequence arguments. */
        NFSM_BUILD(tl, uint32_t *, NFSX_V4SESSIONID + 5 * NFSX_UNSIGNED);
        bcopy(sessionid, tl, NFSX_V4SESSIONID);
        tl += NFSX_V4SESSIONID / NFSX_UNSIGNED;
        nd->nd_slotseq = tl;
        *tl++ = txdr_unsigned(slotseq);
        *tl++ = txdr_unsigned(slotpos);
        *tl++ = txdr_unsigned(maxslot);
        if (dont_replycache == 0)
                *tl++ = newnfs_true;
        else
                *tl++ = newnfs_false;
        *tl = 0;                        /* No referring call list, for now. */
        nd->nd_flag |= ND_HASSEQUENCE;
        return (0);
}

/*
 * Get a session for the callback.
 */
static int
nfsv4_getcbsession(struct nfsclient *clp, struct nfsdsession **sepp)
{
        struct nfsdsession *sep;

        NFSLOCKSTATE();
        LIST_FOREACH(sep, &clp->lc_session, sess_list) {
                if ((sep->sess_crflags & NFSV4CRSESS_CONNBACKCHAN) != 0)
                        break;
        }
        if (sep == NULL) {
                NFSUNLOCKSTATE();
                return (NFSERR_BADSESSION);
        }
        sep->sess_refcnt++;
        *sepp = sep;
        NFSUNLOCKSTATE();
        return (0);
}

/*
 * Free up all backchannel xprts.  This needs to be done when the nfsd threads
 * exit, since those transports will all be going away.
 * This is only called after all the nfsd threads are done performing RPCs,
 * so locking shouldn't be an issue.
 */
APPLESTATIC void
nfsrv_freeallbackchannel_xprts(void)
{
        struct nfsdsession *sep;
        struct nfsclient *clp;
        SVCXPRT *xprt;
        int i;

        for (i = 0; i < nfsrv_clienthashsize; i++) {
                LIST_FOREACH(clp, &nfsclienthash[i], lc_hash) {
                        LIST_FOREACH(sep, &clp->lc_session, sess_list) {
                                xprt = sep->sess_cbsess.nfsess_xprt;
                                sep->sess_cbsess.nfsess_xprt = NULL;
                                if (xprt != NULL)
                                        SVC_RELEASE(xprt);
                        }
                }
        }
}