FreeBSD/Linux Kernel Cross Reference
sys/fs/nfsclient/nfs_clstate.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * 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("$FreeBSD$");
    
    /*
     * These functions implement the client side state handling for NFSv4.
     * NFSv4 state handling:
     * - A lockowner is used to determine lock contention, so it
     *   corresponds directly to a Posix pid. (1 to 1 mapping)
     * - The correct granularity of an OpenOwner is not nearly so
     *   obvious. An OpenOwner does the following:
     *   - provides a serial sequencing of Open/Close/Lock-with-new-lockowner
     *   - is used to check for Open/Share contention (not applicable to
     *     this client, since all Opens are Deny_None)
     *   As such, I considered both extreme.
     *   1 OpenOwner per ClientID - Simple to manage, but fully serializes
     *   all Open, Close and Lock (with a new lockowner) Ops.
     *   1 OpenOwner for each Open - This one results in an OpenConfirm for
     *   every Open, for most servers.
     *   So, I chose to use the same mapping as I did for LockOwnwers.
     *   The main concern here is that you can end up with multiple Opens
     *   for the same File Handle, but on different OpenOwners (opens
     *   inherited from parents, grandparents...) and you do not know
     *   which of these the vnodeop close applies to. This is handled by
     *   delaying the Close Op(s) until all of the Opens have been closed.
     *   (It is not yet obvious if this is the correct granularity.)
     * - How the code handles serialization:
     *   - For the ClientId, it uses an exclusive lock while getting its
     *     SetClientId and during recovery. Otherwise, it uses a shared
     *     lock via a reference count.
     *   - For the rest of the data structures, it uses an SMP mutex
     *     (once the nfs client is SMP safe) and doesn't sleep while
     *     manipulating the linked lists.
     *   - The serialization of Open/Close/Lock/LockU falls out in the
     *     "wash", since OpenOwners and LockOwners are both mapped from
     *     Posix pid. In other words, there is only one Posix pid using
     *     any given owner, so that owner is serialized. (If you change
     *     the granularity of the OpenOwner, then code must be added to
     *     serialize Ops on the OpenOwner.)
     * - When to get rid of OpenOwners and LockOwners.
     *   - The function nfscl_cleanup_common() is executed after a process exits.
     *     It goes through the client list looking for all Open and Lock Owners.
     *     When one is found, it is marked "defunct" or in the case of
     *     an OpenOwner without any Opens, freed.
     *     The renew thread scans for defunct Owners and gets rid of them,
     *     if it can. The LockOwners will also be deleted when the
     *     associated Open is closed.
     *   - If the LockU or Close Op(s) fail during close in a way
     *     that could be recovered upon retry, they are relinked to the
     *     ClientId's defunct open list and retried by the renew thread
     *     until they succeed or an unmount/recovery occurs.
     *     (Since we are done with them, they do not need to be recovered.)
     */
    
    #include <fs/nfs/nfsport.h>
    
    /*
     * Global variables
     */
    extern struct nfsstatsv1 nfsstatsv1;
    extern struct nfsreqhead nfsd_reqq;
    extern u_int32_t newnfs_false, newnfs_true;
    extern int nfscl_debuglevel;
    extern int nfscl_enablecallb;
    extern int nfs_numnfscbd;
    NFSREQSPINLOCK;
    NFSCLSTATEMUTEX;
    int nfscl_inited = 0;
    struct nfsclhead nfsclhead;     /* Head of clientid list */
    int nfscl_deleghighwater = NFSCLDELEGHIGHWATER;
    int nfscl_layouthighwater = NFSCLLAYOUTHIGHWATER;
   
   static int nfscl_delegcnt = 0;
   static int nfscl_layoutcnt = 0;
   static int nfscl_getopen(struct nfsclownerhead *, struct nfsclopenhash *,
       u_int8_t *, int, u_int8_t *, u_int8_t *, u_int32_t,
       struct nfscllockowner **, struct nfsclopen **);
   static bool nfscl_checkown(struct nfsclowner *, struct nfsclopen *, uint8_t *,
       uint8_t *, struct nfscllockowner **, struct nfsclopen **,
       struct nfsclopen **);
   static void nfscl_clrelease(struct nfsclclient *);
   static void nfscl_unlinkopen(struct nfsclopen *);
   static void nfscl_cleanclient(struct nfsclclient *);
   static void nfscl_expireclient(struct nfsclclient *, struct nfsmount *,
       struct ucred *, NFSPROC_T *);
   static int nfscl_expireopen(struct nfsclclient *, struct nfsclopen *,
       struct nfsmount *, struct ucred *, NFSPROC_T *);
   static void nfscl_recover(struct nfsclclient *, bool *, struct ucred *,
       NFSPROC_T *);
   static void nfscl_insertlock(struct nfscllockowner *, struct nfscllock *,
       struct nfscllock *, int);
   static int nfscl_updatelock(struct nfscllockowner *, struct nfscllock **,
       struct nfscllock **, int);
   static void nfscl_delegreturnall(struct nfsclclient *, NFSPROC_T *,
       struct nfscldeleghead *);
   static u_int32_t nfscl_nextcbident(void);
   static mount_t nfscl_getmnt(int, uint8_t *, u_int32_t, struct nfsclclient **);
   static struct nfsclclient *nfscl_getclnt(u_int32_t);
   static struct nfsclclient *nfscl_getclntsess(uint8_t *);
   static struct nfscldeleg *nfscl_finddeleg(struct nfsclclient *, u_int8_t *,
       int);
   static void nfscl_retoncloselayout(vnode_t, struct nfsclclient *, uint8_t *,
       int, struct nfsclrecalllayout **, struct nfscllayout **);
   static void nfscl_reldevinfo_locked(struct nfscldevinfo *);
   static struct nfscllayout *nfscl_findlayout(struct nfsclclient *, u_int8_t *,
       int);
   static struct nfscldevinfo *nfscl_finddevinfo(struct nfsclclient *, uint8_t *);
   static int nfscl_checkconflict(struct nfscllockownerhead *, struct nfscllock *,
       u_int8_t *, struct nfscllock **);
   static void nfscl_freealllocks(struct nfscllockownerhead *, int);
   static int nfscl_localconflict(struct nfsclclient *, u_int8_t *, int,
       struct nfscllock *, u_int8_t *, struct nfscldeleg *, struct nfscllock **);
   static void nfscl_newopen(struct nfsclclient *, struct nfscldeleg *,
       struct nfsclowner **, struct nfsclowner **, struct nfsclopen **,
       struct nfsclopen **, u_int8_t *, u_int8_t *, int, struct ucred *, int *);
   static int nfscl_moveopen(vnode_t , struct nfsclclient *,
       struct nfsmount *, struct nfsclopen *, struct nfsclowner *,
       struct nfscldeleg *, struct ucred *, NFSPROC_T *);
   static void nfscl_totalrecall(struct nfsclclient *);
   static int nfscl_relock(vnode_t , struct nfsclclient *, struct nfsmount *,
       struct nfscllockowner *, struct nfscllock *, struct ucred *, NFSPROC_T *);
   static int nfscl_tryopen(struct nfsmount *, vnode_t , u_int8_t *, int,
       u_int8_t *, int, u_int32_t, struct nfsclopen *, u_int8_t *, int,
       struct nfscldeleg **, int, u_int32_t, struct ucred *, NFSPROC_T *);
   static int nfscl_trylock(struct nfsmount *, vnode_t , u_int8_t *,
       int, struct nfscllockowner *, int, int, u_int64_t, u_int64_t, short,
       struct ucred *, NFSPROC_T *);
   static int nfsrpc_reopen(struct nfsmount *, u_int8_t *, int, u_int32_t,
       struct nfsclopen *, struct nfscldeleg **, struct ucred *, NFSPROC_T *);
   static void nfscl_freedeleg(struct nfscldeleghead *, struct nfscldeleg *,
       bool);
   static int nfscl_errmap(struct nfsrv_descript *, u_int32_t);
   static void nfscl_cleanup_common(struct nfsclclient *, u_int8_t *);
   static int nfscl_recalldeleg(struct nfsclclient *, struct nfsmount *,
       struct nfscldeleg *, vnode_t, struct ucred *, NFSPROC_T *, int,
       vnode_t *);
   static void nfscl_freeopenowner(struct nfsclowner *, int);
   static void nfscl_cleandeleg(struct nfscldeleg *);
   static int nfscl_trydelegreturn(struct nfscldeleg *, struct ucred *,
       struct nfsmount *, NFSPROC_T *);
   static void nfscl_emptylockowner(struct nfscllockowner *,
       struct nfscllockownerfhhead *);
   static void nfscl_mergeflayouts(struct nfsclflayouthead *,
       struct nfsclflayouthead *);
   static int nfscl_layoutrecall(int, struct nfscllayout *, uint32_t, uint64_t,
       uint64_t, uint32_t, uint32_t, uint32_t, char *, struct nfsclrecalllayout *);
   static int nfscl_seq(uint32_t, uint32_t);
   static void nfscl_layoutreturn(struct nfsmount *, struct nfscllayout *,
       struct ucred *, NFSPROC_T *);
   static void nfscl_dolayoutcommit(struct nfsmount *, struct nfscllayout *,
       struct ucred *, NFSPROC_T *);
   
   static short nfscberr_null[] = {
           0,
           0,
   };
   
   static short nfscberr_getattr[] = {
           NFSERR_RESOURCE,
           NFSERR_BADHANDLE,
           NFSERR_BADXDR,
           NFSERR_RESOURCE,
           NFSERR_SERVERFAULT,
           0,
   };
   
   static short nfscberr_recall[] = {
           NFSERR_RESOURCE,
           NFSERR_BADHANDLE,
           NFSERR_BADSTATEID,
           NFSERR_BADXDR,
           NFSERR_RESOURCE,
           NFSERR_SERVERFAULT,
           0,
   };
   
   static short *nfscl_cberrmap[] = {
           nfscberr_null,
           nfscberr_null,
           nfscberr_null,
           nfscberr_getattr,
           nfscberr_recall
   };
   
   #define NETFAMILY(clp) \
                   (((clp)->nfsc_flags & NFSCLFLAGS_AFINET6) ? AF_INET6 : AF_INET)
   
   /*
    * Called for an open operation.
    * If the nfhp argument is NULL, just get an openowner.
    */
   int
   nfscl_open(vnode_t vp, u_int8_t *nfhp, int fhlen, u_int32_t amode, int usedeleg,
       struct ucred *cred, NFSPROC_T *p, struct nfsclowner **owpp,
       struct nfsclopen **opp, int *newonep, int *retp, int lockit, bool firstref)
   {
           struct nfsclclient *clp;
           struct nfsclowner *owp, *nowp;
           struct nfsclopen *op = NULL, *nop = NULL;
           struct nfscldeleg *dp;
           struct nfsclownerhead *ohp;
           u_int8_t own[NFSV4CL_LOCKNAMELEN];
           int ret;
   
           if (newonep != NULL)
                   *newonep = 0;
           if (opp != NULL)
                   *opp = NULL;
           if (owpp != NULL)
                   *owpp = NULL;
   
           /*
            * Might need one or both of these, so MALLOC them now, to
            * avoid a tsleep() in MALLOC later.
            */
           nowp = malloc(sizeof (struct nfsclowner),
               M_NFSCLOWNER, M_WAITOK);
           if (nfhp != NULL) {
               nop = malloc(sizeof (struct nfsclopen) +
                   fhlen - 1, M_NFSCLOPEN, M_WAITOK);
               nop->nfso_hash.le_prev = NULL;
           }
           ret = nfscl_getcl(vp->v_mount, cred, p, false, firstref, &clp);
           if (ret != 0) {
                   free(nowp, M_NFSCLOWNER);
                   if (nop != NULL)
                           free(nop, M_NFSCLOPEN);
                   return (ret);
           }
   
           /*
            * Get the Open iff it already exists.
            * If none found, add the new one or return error, depending upon
            * "create".
            */
           NFSLOCKCLSTATE();
           dp = NULL;
           /* First check the delegation list */
           if (nfhp != NULL && usedeleg) {
                   LIST_FOREACH(dp, NFSCLDELEGHASH(clp, nfhp, fhlen), nfsdl_hash) {
                           if (dp->nfsdl_fhlen == fhlen &&
                               !NFSBCMP(nfhp, dp->nfsdl_fh, fhlen)) {
                                   if (!(amode & NFSV4OPEN_ACCESSWRITE) ||
                                       (dp->nfsdl_flags & NFSCLDL_WRITE))
                                           break;
                                   dp = NULL;
                                   break;
                           }
                   }
           }
   
           /* For NFSv4.1/4.2 and this option, use a single open_owner. */
           if (NFSHASONEOPENOWN(VFSTONFS(vp->v_mount)))
                   nfscl_filllockowner(NULL, own, F_POSIX);
           else
                   nfscl_filllockowner(p->td_proc, own, F_POSIX);
           if (dp != NULL)
                   ohp = &dp->nfsdl_owner;
           else
                   ohp = &clp->nfsc_owner;
           /* Now, search for an openowner */
           LIST_FOREACH(owp, ohp, nfsow_list) {
                   if (!NFSBCMP(owp->nfsow_owner, own, NFSV4CL_LOCKNAMELEN))
                           break;
           }
   
           /*
            * Create a new open, as required.
            */
           nfscl_newopen(clp, dp, &owp, &nowp, &op, &nop, own, nfhp, fhlen,
               cred, newonep);
   
           /*
            * Now, check the mode on the open and return the appropriate
            * value.
            */
           if (retp != NULL) {
                   if (nfhp != NULL && dp != NULL && nop == NULL)
                           /* new local open on delegation */
                           *retp = NFSCLOPEN_SETCRED;
                   else
                           *retp = NFSCLOPEN_OK;
           }
           if (op != NULL && (amode & ~(op->nfso_mode))) {
                   op->nfso_mode |= amode;
                   if (retp != NULL && dp == NULL)
                           *retp = NFSCLOPEN_DOOPEN;
           }
   
           /*
            * Serialize modifications to the open owner for multiple threads
            * within the same process using a read/write sleep lock.
            * For NFSv4.1 and a single OpenOwner, allow concurrent open operations
            * by acquiring a shared lock.  The close operations still use an
            * exclusive lock for this case.
            */
           if (lockit != 0) {
                   if (NFSHASONEOPENOWN(VFSTONFS(vp->v_mount))) {
                           /*
                            * Get a shared lock on the OpenOwner, but first
                            * wait for any pending exclusive lock, so that the
                            * exclusive locker gets priority.
                            */
                           nfsv4_lock(&owp->nfsow_rwlock, 0, NULL,
                               NFSCLSTATEMUTEXPTR, NULL);
                           nfsv4_getref(&owp->nfsow_rwlock, NULL,
                               NFSCLSTATEMUTEXPTR, NULL);
                   } else
                           nfscl_lockexcl(&owp->nfsow_rwlock, NFSCLSTATEMUTEXPTR);
           }
           NFSUNLOCKCLSTATE();
           if (nowp != NULL)
                   free(nowp, M_NFSCLOWNER);
           if (nop != NULL)
                   free(nop, M_NFSCLOPEN);
           if (owpp != NULL)
                   *owpp = owp;
           if (opp != NULL)
                   *opp = op;
           return (0);
   }
   
   /*
    * Create a new open, as required.
    */
   static void
   nfscl_newopen(struct nfsclclient *clp, struct nfscldeleg *dp,
       struct nfsclowner **owpp, struct nfsclowner **nowpp, struct nfsclopen **opp,
       struct nfsclopen **nopp, u_int8_t *own, u_int8_t *fhp, int fhlen,
       struct ucred *cred, int *newonep)
   {
           struct nfsclowner *owp = *owpp, *nowp;
           struct nfsclopen *op, *nop;
   
           if (nowpp != NULL)
                   nowp = *nowpp;
           else
                   nowp = NULL;
           if (nopp != NULL)
                   nop = *nopp;
           else
                   nop = NULL;
           if (owp == NULL && nowp != NULL) {
                   NFSBCOPY(own, nowp->nfsow_owner, NFSV4CL_LOCKNAMELEN);
                   LIST_INIT(&nowp->nfsow_open);
                   nowp->nfsow_clp = clp;
                   nowp->nfsow_seqid = 0;
                   nowp->nfsow_defunct = 0;
                   nfscl_lockinit(&nowp->nfsow_rwlock);
                   if (dp != NULL) {
                           nfsstatsv1.cllocalopenowners++;
                           LIST_INSERT_HEAD(&dp->nfsdl_owner, nowp, nfsow_list);
                   } else {
                           nfsstatsv1.clopenowners++;
                           LIST_INSERT_HEAD(&clp->nfsc_owner, nowp, nfsow_list);
                   }
                   owp = *owpp = nowp;
                   *nowpp = NULL;
                   if (newonep != NULL)
                           *newonep = 1;
           }
   
            /* If an fhp has been specified, create an Open as well. */
           if (fhp != NULL) {
                   /* and look for the correct open, based upon FH */
                   LIST_FOREACH(op, &owp->nfsow_open, nfso_list) {
                           if (op->nfso_fhlen == fhlen &&
                               !NFSBCMP(op->nfso_fh, fhp, fhlen))
                                   break;
                   }
                   if (op == NULL && nop != NULL) {
                           nop->nfso_own = owp;
                           nop->nfso_mode = 0;
                           nop->nfso_opencnt = 0;
                           nop->nfso_posixlock = 1;
                           nop->nfso_fhlen = fhlen;
                           NFSBCOPY(fhp, nop->nfso_fh, fhlen);
                           LIST_INIT(&nop->nfso_lock);
                           nop->nfso_stateid.seqid = 0;
                           nop->nfso_stateid.other[0] = 0;
                           nop->nfso_stateid.other[1] = 0;
                           nop->nfso_stateid.other[2] = 0;
                           KASSERT(cred != NULL, ("%s: cred NULL\n", __func__));
                           newnfs_copyincred(cred, &nop->nfso_cred);
                           if (dp != NULL) {
                                   TAILQ_REMOVE(&clp->nfsc_deleg, dp, nfsdl_list);
                                   TAILQ_INSERT_HEAD(&clp->nfsc_deleg, dp,
                                       nfsdl_list);
                                   dp->nfsdl_timestamp = NFSD_MONOSEC + 120;
                                   nfsstatsv1.cllocalopens++;
                           } else {
                                   LIST_INSERT_HEAD(NFSCLOPENHASH(clp, fhp, fhlen),
                                       nop, nfso_hash);
                                   nfsstatsv1.clopens++;
                           }
                           LIST_INSERT_HEAD(&owp->nfsow_open, nop, nfso_list);
                           *opp = nop;
                           *nopp = NULL;
                           if (newonep != NULL)
                                   *newonep = 1;
                   } else {
                           *opp = op;
                   }
           }
   }
   
   /*
    * Called to find/add a delegation to a client.
    */
   int
   nfscl_deleg(mount_t mp, struct nfsclclient *clp, u_int8_t *nfhp,
       int fhlen, struct ucred *cred, NFSPROC_T *p, struct nfscldeleg **dpp)
   {
           struct nfscldeleg *dp = *dpp, *tdp;
           struct nfsmount *nmp;
   
           KASSERT(mp != NULL, ("nfscl_deleg: mp NULL"));
           nmp = VFSTONFS(mp);
           /*
            * First, if we have received a Read delegation for a file on a
            * read/write file system, just return it, because they aren't
            * useful, imho.
            */
           if (dp != NULL && !NFSMNT_RDONLY(mp) &&
               (dp->nfsdl_flags & NFSCLDL_READ)) {
                   nfscl_trydelegreturn(dp, cred, nmp, p);
                   free(dp, M_NFSCLDELEG);
                   *dpp = NULL;
                   return (0);
           }
   
           /*
            * Since a delegation might be added to the mount,
            * set NFSMNTP_DELEGISSUED now.  If a delegation already
            * exagain ists, setting this flag is harmless.
            */
           NFSLOCKMNT(nmp);
           nmp->nm_privflag |= NFSMNTP_DELEGISSUED;
           NFSUNLOCKMNT(nmp);
   
           /* Look for the correct deleg, based upon FH */
           NFSLOCKCLSTATE();
           tdp = nfscl_finddeleg(clp, nfhp, fhlen);
           if (tdp == NULL) {
                   if (dp == NULL) {
                           NFSUNLOCKCLSTATE();
                           return (NFSERR_BADSTATEID);
                   }
                   *dpp = NULL;
                   TAILQ_INSERT_HEAD(&clp->nfsc_deleg, dp, nfsdl_list);
                   LIST_INSERT_HEAD(NFSCLDELEGHASH(clp, nfhp, fhlen), dp,
                       nfsdl_hash);
                   dp->nfsdl_timestamp = NFSD_MONOSEC + 120;
                   nfsstatsv1.cldelegates++;
                   nfscl_delegcnt++;
           } else {
                   /*
                    * Delegation already exists, what do we do if a new one??
                    */
                   if (dp != NULL) {
                           printf("Deleg already exists!\n");
                           free(dp, M_NFSCLDELEG);
                           *dpp = NULL;
                   } else {
                           *dpp = tdp;
                   }
           }
           NFSUNLOCKCLSTATE();
           return (0);
   }
   
   /*
    * Find a delegation for this file handle. Return NULL upon failure.
    */
   static struct nfscldeleg *
   nfscl_finddeleg(struct nfsclclient *clp, u_int8_t *fhp, int fhlen)
   {
           struct nfscldeleg *dp;
   
           LIST_FOREACH(dp, NFSCLDELEGHASH(clp, fhp, fhlen), nfsdl_hash) {
               if (dp->nfsdl_fhlen == fhlen &&
                   !NFSBCMP(dp->nfsdl_fh, fhp, fhlen))
                   break;
           }
           return (dp);
   }
   
   /*
    * Get a stateid for an I/O operation. First, look for an open and iff
    * found, return either a lockowner stateid or the open stateid.
    * If no Open is found, just return error and the special stateid of all zeros.
    */
   int
   nfscl_getstateid(vnode_t vp, u_int8_t *nfhp, int fhlen, u_int32_t mode,
       int fords, struct ucred *cred, NFSPROC_T *p, nfsv4stateid_t *stateidp,
       void **lckpp)
   {
           struct nfsclclient *clp;
           struct nfsclopen *op = NULL, *top;
           struct nfsclopenhash *oph;
           struct nfscllockowner *lp;
           struct nfscldeleg *dp;
           struct nfsnode *np;
           struct nfsmount *nmp;
           u_int8_t own[NFSV4CL_LOCKNAMELEN], lockown[NFSV4CL_LOCKNAMELEN];
           int error;
           bool done;
   
           *lckpp = NULL;
           /*
            * Initially, just set the special stateid of all zeros.
            * (Don't do this for a DS, since the special stateid can't be used.)
            */
           if (fords == 0) {
                   stateidp->seqid = 0;
                   stateidp->other[0] = 0;
                   stateidp->other[1] = 0;
                   stateidp->other[2] = 0;
           }
           if (vnode_vtype(vp) != VREG)
                   return (EISDIR);
           np = VTONFS(vp);
           nmp = VFSTONFS(vp->v_mount);
   
           /*
            * For "oneopenown" mounts, first check for a cached open in the
            * NFS vnode, that can be used as a stateid.  This can only be
            * done if no delegations have been issued to the mount and no
            * byte range file locking has been done for the file.
            */
           if (NFSHASNFSV4N(nmp) && NFSHASONEOPENOWN(nmp) && fords == 0) {
                   NFSLOCKMNT(nmp);
                   NFSLOCKNODE(np);
                   if ((nmp->nm_privflag & NFSMNTP_DELEGISSUED) == 0 &&
                       (np->n_flag & NMIGHTBELOCKED) == 0 &&
                       np->n_openstateid != NULL) {
                           stateidp->seqid = 0;
                           stateidp->other[0] =
                               np->n_openstateid->nfso_stateid.other[0];
                           stateidp->other[1] =
                               np->n_openstateid->nfso_stateid.other[1];
                           stateidp->other[2] =
                               np->n_openstateid->nfso_stateid.other[2];
                           NFSUNLOCKNODE(np);
                           NFSUNLOCKMNT(nmp);
                           return (0);
                   }
                   NFSUNLOCKNODE(np);
                   NFSUNLOCKMNT(nmp);
           }
   
           NFSLOCKCLSTATE();
           clp = nfscl_findcl(nmp);
           if (clp == NULL) {
                   NFSUNLOCKCLSTATE();
                   return (EACCES);
           }
   
           /*
            * Wait for recovery to complete.
            */
           while ((clp->nfsc_flags & NFSCLFLAGS_RECVRINPROG))
                   (void) nfsmsleep(&clp->nfsc_flags, NFSCLSTATEMUTEXPTR,
                       PZERO, "nfsrecvr", NULL);
   
           /*
            * First, look for a delegation.
            */
           LIST_FOREACH(dp, NFSCLDELEGHASH(clp, nfhp, fhlen), nfsdl_hash) {
                   if (dp->nfsdl_fhlen == fhlen &&
                       !NFSBCMP(nfhp, dp->nfsdl_fh, fhlen)) {
                           if (!(mode & NFSV4OPEN_ACCESSWRITE) ||
                               (dp->nfsdl_flags & NFSCLDL_WRITE)) {
                                   if (NFSHASNFSV4N(nmp))
                                           stateidp->seqid = 0;
                                   else
                                           stateidp->seqid =
                                               dp->nfsdl_stateid.seqid;
                                   stateidp->other[0] = dp->nfsdl_stateid.other[0];
                                   stateidp->other[1] = dp->nfsdl_stateid.other[1];
                                   stateidp->other[2] = dp->nfsdl_stateid.other[2];
                                   if (!(np->n_flag & NDELEGRECALL)) {
                                           TAILQ_REMOVE(&clp->nfsc_deleg, dp,
                                               nfsdl_list);
                                           TAILQ_INSERT_HEAD(&clp->nfsc_deleg, dp,
                                               nfsdl_list);
                                           dp->nfsdl_timestamp = NFSD_MONOSEC +
                                               120;
                                           dp->nfsdl_rwlock.nfslock_usecnt++;
                                           *lckpp = (void *)&dp->nfsdl_rwlock;
                                   }
                                   NFSUNLOCKCLSTATE();
                                   return (0);
                           }
                           break;
                   }
           }
   
           if (p != NULL) {
                   /*
                    * If p != NULL, we want to search the parentage tree
                    * for a matching OpenOwner and use that.
                    */
                   if (NFSHASONEOPENOWN(VFSTONFS(vp->v_mount)))
                           nfscl_filllockowner(NULL, own, F_POSIX);
                   else
                           nfscl_filllockowner(p->td_proc, own, F_POSIX);
                   nfscl_filllockowner(p->td_proc, lockown, F_POSIX);
                   lp = NULL;
                   error = nfscl_getopen(NULL, clp->nfsc_openhash, nfhp, fhlen,
                       own, lockown, mode, &lp, &op);
                   if (error == 0 && lp != NULL && fords == 0) {
                           /* Don't return a lock stateid for a DS. */
                           if (NFSHASNFSV4N(nmp))
                                   stateidp->seqid = 0;
                           else
                                   stateidp->seqid = lp->nfsl_stateid.seqid;
                           stateidp->other[0] =
                               lp->nfsl_stateid.other[0];
                           stateidp->other[1] =
                               lp->nfsl_stateid.other[1];
                           stateidp->other[2] =
                               lp->nfsl_stateid.other[2];
                           NFSUNLOCKCLSTATE();
                           return (0);
                   }
           }
           if (op == NULL) {
                   /* If not found, just look for any OpenOwner that will work. */
                   top = NULL;
                   done = false;
                   oph = NFSCLOPENHASH(clp, nfhp, fhlen);
                   LIST_FOREACH(op, oph, nfso_hash) {
                           if (op->nfso_fhlen == fhlen &&
                               !NFSBCMP(op->nfso_fh, nfhp, fhlen)) {
                                   if (top == NULL && (op->nfso_mode &
                                       NFSV4OPEN_ACCESSWRITE) != 0 &&
                                       (mode & NFSV4OPEN_ACCESSREAD) != 0)
                                           top = op;
                                   if ((mode & op->nfso_mode) == mode) {
                                           /* LRU order the hash list. */
                                           LIST_REMOVE(op, nfso_hash);
                                           LIST_INSERT_HEAD(oph, op, nfso_hash);
                                           done = true;
                                           break;
                                   }
                           }
                   }
                   if (!done) {
                           NFSCL_DEBUG(2, "openmode top=%p\n", top);
                           if (top == NULL || NFSHASOPENMODE(nmp)) {
                                   NFSUNLOCKCLSTATE();
                                   return (ENOENT);
                           } else
                                   op = top;
                   }
                   /*
                    * For read aheads or write behinds, use the open cred.
                    * A read ahead or write behind is indicated by p == NULL.
                    */
                   if (p == NULL)
                           newnfs_copycred(&op->nfso_cred, cred);
           }
   
           /*
            * No lock stateid, so return the open stateid.
            */
           if (NFSHASNFSV4N(nmp))
                   stateidp->seqid = 0;
           else
                   stateidp->seqid = op->nfso_stateid.seqid;
           stateidp->other[0] = op->nfso_stateid.other[0];
           stateidp->other[1] = op->nfso_stateid.other[1];
           stateidp->other[2] = op->nfso_stateid.other[2];
           NFSUNLOCKCLSTATE();
           return (0);
   }
   
   /*
    * Search for a matching file, mode and, optionally, lockowner.
    */
   static int
   nfscl_getopen(struct nfsclownerhead *ohp, struct nfsclopenhash *ohashp,
       u_int8_t *nfhp, int fhlen, u_int8_t *openown, u_int8_t *lockown,
       u_int32_t mode, struct nfscllockowner **lpp, struct nfsclopen **opp)
   {
           struct nfsclowner *owp;
           struct nfsclopen *op, *rop, *rop2;
           struct nfsclopenhash *oph;
           bool keep_looping;
   
           KASSERT(ohp == NULL || ohashp == NULL, ("nfscl_getopen: "
               "only one of ohp and ohashp can be set"));
           if (lpp != NULL)
                   *lpp = NULL;
           /*
            * rop will be set to the open to be returned. There are three
            * variants of this, all for an open of the correct file:
            * 1 - A match of lockown.
            * 2 - A match of the openown, when no lockown match exists.
            * 3 - A match for any open, if no openown or lockown match exists.
            * Looking for #2 over #3 probably isn't necessary, but since
            * RFC3530 is vague w.r.t. the relationship between openowners and
            * lockowners, I think this is the safer way to go.
            */
           rop = NULL;
           rop2 = NULL;
           keep_looping = true;
           /* Search the client list */
           if (ohashp == NULL) {
                   /* Search the local opens on the delegation. */
                   LIST_FOREACH(owp, ohp, nfsow_list) {
                           /* and look for the correct open */
                           LIST_FOREACH(op, &owp->nfsow_open, nfso_list) {
                                   if (op->nfso_fhlen == fhlen &&
                                       !NFSBCMP(op->nfso_fh, nfhp, fhlen)
                                       && (op->nfso_mode & mode) == mode)
                                           keep_looping = nfscl_checkown(owp, op, openown,
                                               lockown, lpp, &rop, &rop2);
                                   if (!keep_looping)
                                           break;
                           }
                           if (!keep_looping)
                                   break;
                   }
           } else {
                   /* Search for matching opens on the hash list. */
                   oph = &ohashp[NFSCLOPENHASHFUNC(nfhp, fhlen)];
                   LIST_FOREACH(op, oph, nfso_hash) {
                           if (op->nfso_fhlen == fhlen &&
                               !NFSBCMP(op->nfso_fh, nfhp, fhlen)
                               && (op->nfso_mode & mode) == mode)
                                   keep_looping = nfscl_checkown(op->nfso_own, op,
                                       openown, lockown, lpp, &rop, &rop2);
                           if (!keep_looping) {
                                   /* LRU order the hash list. */
                                   LIST_REMOVE(op, nfso_hash);
                                   LIST_INSERT_HEAD(oph, op, nfso_hash);
                                   break;
                           }
                   }
           }
           if (rop == NULL)
                   rop = rop2;
           if (rop == NULL)
                   return (EBADF);
           *opp = rop;
           return (0);
   }
   
   /* Check for an owner match. */
   static bool
   nfscl_checkown(struct nfsclowner *owp, struct nfsclopen *op, uint8_t *openown,
       uint8_t *lockown, struct nfscllockowner **lpp, struct nfsclopen **ropp,
       struct nfsclopen **ropp2)
   {
           struct nfscllockowner *lp;
           bool keep_looping;
   
           keep_looping = true;
           if (lpp != NULL) {
                   /* Now look for a matching lockowner. */
                   LIST_FOREACH(lp, &op->nfso_lock, nfsl_list) {
                           if (!NFSBCMP(lp->nfsl_owner, lockown,
                               NFSV4CL_LOCKNAMELEN)) {
                                   *lpp = lp;
                                   *ropp = op;
                                   return (false);
                           }
                   }
           }
           if (*ropp == NULL && !NFSBCMP(owp->nfsow_owner, openown,
               NFSV4CL_LOCKNAMELEN)) {
                   *ropp = op;
                   if (lpp == NULL)
                           keep_looping = false;
           }
           if (*ropp2 == NULL)
                   *ropp2 = op;
           return (keep_looping);
   }
   
   /*
    * Release use of an open owner. Called when open operations are done
    * with the open owner.
    */
   void
   nfscl_ownerrelease(struct nfsmount *nmp, struct nfsclowner *owp,
       __unused int error, __unused int candelete, int unlocked)
   {
   
           if (owp == NULL)
                   return;
           NFSLOCKCLSTATE();
           if (unlocked == 0) {
                   if (NFSHASONEOPENOWN(nmp))
                           nfsv4_relref(&owp->nfsow_rwlock);
                   else
                           nfscl_lockunlock(&owp->nfsow_rwlock);
           }
           nfscl_clrelease(owp->nfsow_clp);
           NFSUNLOCKCLSTATE();
   }
   
   /*
    * Release use of an open structure under an open owner.
    */
   void
   nfscl_openrelease(struct nfsmount *nmp, struct nfsclopen *op, int error,
       int candelete)
   {
           struct nfsclclient *clp;
           struct nfsclowner *owp;
   
           if (op == NULL)
                   return;
           NFSLOCKCLSTATE();
           owp = op->nfso_own;
           if (NFSHASONEOPENOWN(nmp))
                   nfsv4_relref(&owp->nfsow_rwlock);
           else
                   nfscl_lockunlock(&owp->nfsow_rwlock);
           clp = owp->nfsow_clp;
           if (error && candelete && op->nfso_opencnt == 0)
                   nfscl_freeopen(op, 0, true);
           nfscl_clrelease(clp);
           NFSUNLOCKCLSTATE();
   }
   
   /*
    * Called to get a clientid structure. It will optionally lock the
    * client data structures to do the SetClientId/SetClientId_confirm,
    * but will release that lock and return the clientid with a reference
    * count on it.
    * If the "cred" argument is NULL, a new clientid should not be created.
    * If the "p" argument is NULL, a SetClientID/SetClientIDConfirm cannot
    * be done.
    * It always clpp with a reference count on it, unless returning an error.
    */
   int
   nfscl_getcl(struct mount *mp, struct ucred *cred, NFSPROC_T *p,
       bool tryminvers, bool firstref, struct nfsclclient **clpp)
   {
           struct nfsclclient *clp;
           struct nfsclclient *newclp = NULL;
           struct nfsmount *nmp;
           char uuid[HOSTUUIDLEN];
           int igotlock = 0, error, trystalecnt, clidinusedelay, i;
           u_int16_t idlen = 0;
   
           nmp = VFSTONFS(mp);
           if (cred != NULL) {
                   getcredhostuuid(cred, uuid, sizeof uuid);
                   idlen = strlen(uuid);
                   if (idlen > 0)
                           idlen += sizeof (u_int64_t);
                   else
                           idlen += sizeof (u_int64_t) + 16; /* 16 random bytes */
                   newclp = malloc(
                       sizeof (struct nfsclclient) + idlen - 1, M_NFSCLCLIENT,
                       M_WAITOK | M_ZERO);
           }
           NFSLOCKCLSTATE();
           /*
            * If a forced dismount is already in progress, don't
            * allocate a new clientid and get out now. For the case where
            * clp != NULL, this is a harmless optimization.
            */
           if (NFSCL_FORCEDISM(mp)) {
                   NFSUNLOCKCLSTATE();
                   if (newclp != NULL)
                           free(newclp, M_NFSCLCLIENT);
                   return (EBADF);
           }
           clp = nmp->nm_clp;
           if (clp == NULL) {
                   if (newclp == NULL) {
                           NFSUNLOCKCLSTATE();
                           return (EACCES);
                   }
                   clp = newclp;
                   clp->nfsc_idlen = idlen;
                   LIST_INIT(&clp->nfsc_owner);
                   TAILQ_INIT(&clp->nfsc_deleg);
                   TAILQ_INIT(&clp->nfsc_layout);
                   LIST_INIT(&clp->nfsc_devinfo);
                   for (i = 0; i < NFSCLDELEGHASHSIZE; i++)
                           LIST_INIT(&clp->nfsc_deleghash[i]);
                   for (i = 0; i < NFSCLOPENHASHSIZE; i++)
                           LIST_INIT(&clp->nfsc_openhash[i]);
                   for (i = 0; i < NFSCLLAYOUTHASHSIZE; i++)
                           LIST_INIT(&clp->nfsc_layouthash[i]);
                   clp->nfsc_flags = NFSCLFLAGS_INITED;
                   clp->nfsc_clientidrev = 1;
                   clp->nfsc_cbident = nfscl_nextcbident();
                   nfscl_fillclid(nmp->nm_clval, uuid, clp->nfsc_id,
                       clp->nfsc_idlen);
                   LIST_INSERT_HEAD(&nfsclhead, clp, nfsc_list);
                   nmp->nm_clp = clp;
                   clp->nfsc_nmp = nmp;
           } else {
                   if (newclp != NULL)
                           free(newclp, M_NFSCLCLIENT);
           }
           while ((clp->nfsc_flags & NFSCLFLAGS_HASCLIENTID) == 0 && !igotlock &&
               !NFSCL_FORCEDISM(mp))
                   igotlock = nfsv4_lock(&clp->nfsc_lock, 1, NULL,
                       NFSCLSTATEMUTEXPTR, mp);
           if (igotlock == 0) {
                   /*
                    * Call nfsv4_lock() with "iwantlock == 0" on the firstref so
                    * that it will wait for a pending exclusive lock request.
                    * This gives the exclusive lock request priority over this
                    * shared lock request.
                    * An exclusive lock on nfsc_lock is used mainly for server
                    * crash recoveries and delegation recalls.
                    */
                   if (firstref)
                           nfsv4_lock(&clp->nfsc_lock, 0, NULL, NFSCLSTATEMUTEXPTR,
                               mp);
                   nfsv4_getref(&clp->nfsc_lock, NULL, NFSCLSTATEMUTEXPTR, mp);
           }
           if (igotlock == 0 && NFSCL_FORCEDISM(mp)) {
                   /*
                    * Both nfsv4_lock() and nfsv4_getref() know to check
                    * for NFSCL_FORCEDISM() and return without sleeping to
                    * wait for the exclusive lock to be released, since it
                    * might be held by nfscl_umount() and we need to get out
                    * now for that case and not wait until nfscl_umount()
                    * releases it.
                    */
                   NFSUNLOCKCLSTATE();
                   return (EBADF);
           }
           NFSUNLOCKCLSTATE();
   
           /*
            * If it needs a clientid, do the setclientid now.
            */
           if ((clp->nfsc_flags & NFSCLFLAGS_HASCLIENTID) == 0) {
                   if (!igotlock)
                           panic("nfscl_clget");
                   if (p == NULL || cred == NULL) {
                           NFSLOCKCLSTATE();
                           nfsv4_unlock(&clp->nfsc_lock, 0);
                           NFSUNLOCKCLSTATE();
                           return (EACCES);
                   }
                   /*
                    * If RFC3530 Sec. 14.2.33 is taken literally,
                    * NFSERR_CLIDINUSE will be returned persistently for the
                    * case where a new mount of the same file system is using
                    * a different principal. In practice, NFSERR_CLIDINUSE is
                    * only returned when there is outstanding unexpired state
                    * on the clientid. As such, try for twice the lease
                    * interval, if we know what that is. Otherwise, make a
                    * wild ass guess.
                    * The case of returning NFSERR_STALECLIENTID is far less
                    * likely, but might occur if there is a significant delay
                    * between doing the SetClientID and SetClientIDConfirm Ops,
                    * such that the server throws away the clientid before
                    * receiving the SetClientIDConfirm.
                    */
                   if (clp->nfsc_renew > 0)
                           clidinusedelay = NFSCL_LEASE(clp->nfsc_renew) * 2;
                   else
                           clidinusedelay = 120;
                   trystalecnt = 3;
                   do {
                           error = nfsrpc_setclient(nmp, clp, 0, NULL, cred, p);
                           if (error == NFSERR_STALECLIENTID ||
                              error == NFSERR_STALEDONTRECOVER ||
                              error == NFSERR_BADSESSION ||
                              error == NFSERR_CLIDINUSE) {
                                  (void) nfs_catnap(PZERO, error, "nfs_setcl");
                          } else if (error == NFSERR_MINORVERMISMATCH &&
                              tryminvers) {
                                  if (nmp->nm_minorvers > 0)
                                          nmp->nm_minorvers--;
                                  else
                                          tryminvers = false;
                          }
                  } while (((error == NFSERR_STALECLIENTID ||
                       error == NFSERR_BADSESSION ||
                       error == NFSERR_STALEDONTRECOVER) && --trystalecnt > 0) ||
                      (error == NFSERR_CLIDINUSE && --clidinusedelay > 0) ||
                      (error == NFSERR_MINORVERMISMATCH && tryminvers));
                  if (error) {
                          NFSLOCKCLSTATE();
                          nfsv4_unlock(&clp->nfsc_lock, 0);
                          NFSUNLOCKCLSTATE();
                          return (error);
                  }
                  clp->nfsc_flags |= NFSCLFLAGS_HASCLIENTID;
          }
          if (igotlock) {
                  NFSLOCKCLSTATE();
                  nfsv4_unlock(&clp->nfsc_lock, 1);
                  NFSUNLOCKCLSTATE();
          }
  
          *clpp = clp;
          return (0);
  }
  
  /*
   * Get a reference to a clientid and return it, if valid.
   */
  struct nfsclclient *
  nfscl_findcl(struct nfsmount *nmp)
  {
          struct nfsclclient *clp;
  
          clp = nmp->nm_clp;
          if (clp == NULL || !(clp->nfsc_flags & NFSCLFLAGS_HASCLIENTID))
                  return (NULL);
          return (clp);
  }
  
  /*
   * Release the clientid structure. It may be locked or reference counted.
   */
  static void
  nfscl_clrelease(struct nfsclclient *clp)
  {
  
          if (clp->nfsc_lock.nfslock_lock & NFSV4LOCK_LOCK)
                  nfsv4_unlock(&clp->nfsc_lock, 0);
          else
                  nfsv4_relref(&clp->nfsc_lock);
  }
  
  /*
   * External call for nfscl_clrelease.
   */
  void
  nfscl_clientrelease(struct nfsclclient *clp)
  {
  
          NFSLOCKCLSTATE();
          if (clp->nfsc_lock.nfslock_lock & NFSV4LOCK_LOCK)
                  nfsv4_unlock(&clp->nfsc_lock, 0);
          else
                  nfsv4_relref(&clp->nfsc_lock);
          NFSUNLOCKCLSTATE();
  }
  
  /*
   * Called when wanting to lock a byte region.
   */
  int
  nfscl_getbytelock(vnode_t vp, u_int64_t off, u_int64_t len,
      short type, struct ucred *cred, NFSPROC_T *p, struct nfsclclient *rclp,
      int recovery, void *id, int flags, u_int8_t *rownp, u_int8_t *ropenownp,
      struct nfscllockowner **lpp, int *newonep, int *donelocallyp)
  {
          struct nfscllockowner *lp;
          struct nfsclopen *op;
          struct nfsclclient *clp;
          struct nfscllockowner *nlp;
          struct nfscllock *nlop, *otherlop;
          struct nfscldeleg *dp = NULL, *ldp = NULL;
          struct nfscllockownerhead *lhp = NULL;
          struct nfsnode *np;
          u_int8_t own[NFSV4CL_LOCKNAMELEN], *ownp, openown[NFSV4CL_LOCKNAMELEN];
          u_int8_t *openownp;
          int error = 0, ret, donelocally = 0;
          u_int32_t mode;
  
          /* For Lock Ops, the open mode doesn't matter, so use 0 to match any. */
          mode = 0;
          np = VTONFS(vp);
          *lpp = NULL;
          lp = NULL;
          *newonep = 0;
          *donelocallyp = 0;
  
          /*
           * Might need these, so MALLOC them now, to
           * avoid a tsleep() in MALLOC later.
           */
          nlp = malloc(
              sizeof (struct nfscllockowner), M_NFSCLLOCKOWNER, M_WAITOK);
          otherlop = malloc(
              sizeof (struct nfscllock), M_NFSCLLOCK, M_WAITOK);
          nlop = malloc(
              sizeof (struct nfscllock), M_NFSCLLOCK, M_WAITOK);
          nlop->nfslo_type = type;
          nlop->nfslo_first = off;
          if (len == NFS64BITSSET) {
                  nlop->nfslo_end = NFS64BITSSET;
          } else {
                  nlop->nfslo_end = off + len;
                  if (nlop->nfslo_end <= nlop->nfslo_first)
                          error = NFSERR_INVAL;
          }
  
          if (!error) {
                  if (recovery)
                          clp = rclp;
                  else
                          error = nfscl_getcl(vp->v_mount, cred, p, false, true,
                              &clp);
          }
          if (error) {
                  free(nlp, M_NFSCLLOCKOWNER);
                  free(otherlop, M_NFSCLLOCK);
                  free(nlop, M_NFSCLLOCK);
                  return (error);
          }
  
          op = NULL;
          if (recovery) {
                  ownp = rownp;
                  openownp = ropenownp;
          } else {
                  nfscl_filllockowner(id, own, flags);
                  ownp = own;
                  if (NFSHASONEOPENOWN(VFSTONFS(vp->v_mount)))
                          nfscl_filllockowner(NULL, openown, F_POSIX);
                  else
                          nfscl_filllockowner(p->td_proc, openown, F_POSIX);
                  openownp = openown;
          }
          if (!recovery) {
                  NFSLOCKCLSTATE();
                  /*
                   * First, search for a delegation. If one exists for this file,
                   * the lock can be done locally against it, so long as there
                   * isn't a local lock conflict.
                   */
                  ldp = dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh,
                      np->n_fhp->nfh_len);
                  /* Just sanity check for correct type of delegation */
                  if (dp != NULL && ((dp->nfsdl_flags &
                      (NFSCLDL_RECALL | NFSCLDL_DELEGRET)) != 0 ||
                       (type == F_WRLCK &&
                        (dp->nfsdl_flags & NFSCLDL_WRITE) == 0)))
                          dp = NULL;
          }
          if (dp != NULL) {
                  /* Now, find an open and maybe a lockowner. */
                  ret = nfscl_getopen(&dp->nfsdl_owner, NULL, np->n_fhp->nfh_fh,
                      np->n_fhp->nfh_len, openownp, ownp, mode, NULL, &op);
                  if (ret)
                          ret = nfscl_getopen(NULL, clp->nfsc_openhash,
                              np->n_fhp->nfh_fh, np->n_fhp->nfh_len, openownp,
                              ownp, mode, NULL, &op);
                  if (!ret) {
                          lhp = &dp->nfsdl_lock;
                          TAILQ_REMOVE(&clp->nfsc_deleg, dp, nfsdl_list);
                          TAILQ_INSERT_HEAD(&clp->nfsc_deleg, dp, nfsdl_list);
                          dp->nfsdl_timestamp = NFSD_MONOSEC + 120;
                          donelocally = 1;
                  } else {
                          dp = NULL;
                  }
          }
          if (!donelocally) {
                  /*
                   * Get the related Open and maybe lockowner.
                   */
                  error = nfscl_getopen(NULL, clp->nfsc_openhash,
                      np->n_fhp->nfh_fh, np->n_fhp->nfh_len, openownp,
                      ownp, mode, &lp, &op);
                  if (!error)
                          lhp = &op->nfso_lock;
          }
          if (!error && !recovery)
                  error = nfscl_localconflict(clp, np->n_fhp->nfh_fh,
                      np->n_fhp->nfh_len, nlop, ownp, ldp, NULL);
          if (error) {
                  if (!recovery) {
                          nfscl_clrelease(clp);
                          NFSUNLOCKCLSTATE();
                  }
                  free(nlp, M_NFSCLLOCKOWNER);
                  free(otherlop, M_NFSCLLOCK);
                  free(nlop, M_NFSCLLOCK);
                  return (error);
          }
  
          /*
           * Ok, see if a lockowner exists and create one, as required.
           */
          if (lp == NULL)
                  LIST_FOREACH(lp, lhp, nfsl_list) {
                          if (!NFSBCMP(lp->nfsl_owner, ownp, NFSV4CL_LOCKNAMELEN))
                                  break;
                  }
          if (lp == NULL) {
                  NFSBCOPY(ownp, nlp->nfsl_owner, NFSV4CL_LOCKNAMELEN);
                  if (recovery)
                          NFSBCOPY(ropenownp, nlp->nfsl_openowner,
                              NFSV4CL_LOCKNAMELEN);
                  else
                          NFSBCOPY(op->nfso_own->nfsow_owner, nlp->nfsl_openowner,
                              NFSV4CL_LOCKNAMELEN);
                  nlp->nfsl_seqid = 0;
                  nlp->nfsl_lockflags = flags;
                  nlp->nfsl_inprog = NULL;
                  nfscl_lockinit(&nlp->nfsl_rwlock);
                  LIST_INIT(&nlp->nfsl_lock);
                  if (donelocally) {
                          nlp->nfsl_open = NULL;
                          nfsstatsv1.cllocallockowners++;
                  } else {
                          nlp->nfsl_open = op;
                          nfsstatsv1.cllockowners++;
                  }
                  LIST_INSERT_HEAD(lhp, nlp, nfsl_list);
                  lp = nlp;
                  nlp = NULL;
                  *newonep = 1;
          }
  
          /*
           * Now, update the byte ranges for locks.
           */
          ret = nfscl_updatelock(lp, &nlop, &otherlop, donelocally);
          if (!ret)
                  donelocally = 1;
          if (donelocally) {
                  *donelocallyp = 1;
                  if (!recovery)
                          nfscl_clrelease(clp);
          } else {
                  /*
                   * Serial modifications on the lock owner for multiple threads
                   * for the same process using a read/write lock.
                   */
                  if (!recovery)
                          nfscl_lockexcl(&lp->nfsl_rwlock, NFSCLSTATEMUTEXPTR);
          }
          if (!recovery)
                  NFSUNLOCKCLSTATE();
  
          if (nlp)
                  free(nlp, M_NFSCLLOCKOWNER);
          if (nlop)
                  free(nlop, M_NFSCLLOCK);
          if (otherlop)
                  free(otherlop, M_NFSCLLOCK);
  
          *lpp = lp;
          return (0);
  }
  
  /*
   * Called to unlock a byte range, for LockU.
   */
  int
  nfscl_relbytelock(vnode_t vp, u_int64_t off, u_int64_t len,
      __unused struct ucred *cred, NFSPROC_T *p, int callcnt,
      struct nfsclclient *clp, void *id, int flags,
      struct nfscllockowner **lpp, int *dorpcp)
  {
          struct nfscllockowner *lp;
          struct nfsclopen *op;
          struct nfscllock *nlop, *other_lop = NULL;
          struct nfscldeleg *dp;
          struct nfsnode *np;
          u_int8_t own[NFSV4CL_LOCKNAMELEN];
          int ret = 0, fnd;
  
          np = VTONFS(vp);
          *lpp = NULL;
          *dorpcp = 0;
  
          /*
           * Might need these, so MALLOC them now, to
           * avoid a tsleep() in MALLOC later.
           */
          nlop = malloc(
              sizeof (struct nfscllock), M_NFSCLLOCK, M_WAITOK);
          nlop->nfslo_type = F_UNLCK;
          nlop->nfslo_first = off;
          if (len == NFS64BITSSET) {
                  nlop->nfslo_end = NFS64BITSSET;
          } else {
                  nlop->nfslo_end = off + len;
                  if (nlop->nfslo_end <= nlop->nfslo_first) {
                          free(nlop, M_NFSCLLOCK);
                          return (NFSERR_INVAL);
                  }
          }
          if (callcnt == 0) {
                  other_lop = malloc(
                      sizeof (struct nfscllock), M_NFSCLLOCK, M_WAITOK);
                  *other_lop = *nlop;
          }
          nfscl_filllockowner(id, own, flags);
          dp = NULL;
          NFSLOCKCLSTATE();
          if (callcnt == 0)
                  dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh,
                      np->n_fhp->nfh_len);
  
          /*
           * First, unlock any local regions on a delegation.
           */
          if (dp != NULL) {
                  /* Look for this lockowner. */
                  LIST_FOREACH(lp, &dp->nfsdl_lock, nfsl_list) {
                          if (!NFSBCMP(lp->nfsl_owner, own,
                              NFSV4CL_LOCKNAMELEN))
                                  break;
                  }
                  if (lp != NULL)
                          /* Use other_lop, so nlop is still available */
                          (void)nfscl_updatelock(lp, &other_lop, NULL, 1);
          }
  
          /*
           * Now, find a matching open/lockowner that hasn't already been done,
           * as marked by nfsl_inprog.
           */
          lp = NULL;
          fnd = 0;
          LIST_FOREACH(op, NFSCLOPENHASH(clp, np->n_fhp->nfh_fh,
              np->n_fhp->nfh_len), nfso_hash) {
                  if (op->nfso_fhlen == np->n_fhp->nfh_len &&
                      !NFSBCMP(op->nfso_fh, np->n_fhp->nfh_fh, op->nfso_fhlen)) {
                          LIST_FOREACH(lp, &op->nfso_lock, nfsl_list) {
                                  if (lp->nfsl_inprog == NULL &&
                                      !NFSBCMP(lp->nfsl_owner, own,
                                       NFSV4CL_LOCKNAMELEN)) {
                                          fnd = 1;
                                          break;
                                  }
                          }
                  }
                  if (fnd)
                          break;
          }
  
          if (lp != NULL) {
                  ret = nfscl_updatelock(lp, &nlop, NULL, 0);
                  if (ret)
                          *dorpcp = 1;
                  /*
                   * Serial modifications on the lock owner for multiple
                   * threads for the same process using a read/write lock.
                   */
                  lp->nfsl_inprog = p;
                  nfscl_lockexcl(&lp->nfsl_rwlock, NFSCLSTATEMUTEXPTR);
                  *lpp = lp;
          }
          NFSUNLOCKCLSTATE();
          if (nlop)
                  free(nlop, M_NFSCLLOCK);
          if (other_lop)
                  free(other_lop, M_NFSCLLOCK);
          return (0);
  }
  
  /*
   * Release all lockowners marked in progess for this process and file.
   */
  void
  nfscl_releasealllocks(struct nfsclclient *clp, vnode_t vp, NFSPROC_T *p,
      void *id, int flags)
  {
          struct nfsclopen *op;
          struct nfscllockowner *lp;
          struct nfsnode *np;
          u_int8_t own[NFSV4CL_LOCKNAMELEN];
  
          np = VTONFS(vp);
          nfscl_filllockowner(id, own, flags);
          NFSLOCKCLSTATE();
          LIST_FOREACH(op, NFSCLOPENHASH(clp, np->n_fhp->nfh_fh,
              np->n_fhp->nfh_len), nfso_hash) {
                  if (op->nfso_fhlen == np->n_fhp->nfh_len &&
                      !NFSBCMP(op->nfso_fh, np->n_fhp->nfh_fh, op->nfso_fhlen)) {
                          LIST_FOREACH(lp, &op->nfso_lock, nfsl_list) {
                                  if (lp->nfsl_inprog == p &&
                                      !NFSBCMP(lp->nfsl_owner, own,
                                      NFSV4CL_LOCKNAMELEN)) {
                                          lp->nfsl_inprog = NULL;
                                          nfscl_lockunlock(&lp->nfsl_rwlock);
                                  }
                          }
                  }
          }
          nfscl_clrelease(clp);
          NFSUNLOCKCLSTATE();
  }
  
  /*
   * Called to find out if any bytes within the byte range specified are
   * write locked by the calling process. Used to determine if flushing
   * is required before a LockU.
   * If in doubt, return 1, so the flush will occur.
   */
  int
  nfscl_checkwritelocked(vnode_t vp, struct flock *fl,
      struct ucred *cred, NFSPROC_T *p, void *id, int flags)
  {
          struct nfscllockowner *lp;
          struct nfsclopen *op;
          struct nfsclclient *clp;
          struct nfscllock *lop;
          struct nfscldeleg *dp;
          struct nfsnode *np;
          u_int64_t off, end;
          u_int8_t own[NFSV4CL_LOCKNAMELEN];
          int error = 0;
  
          np = VTONFS(vp);
          switch (fl->l_whence) {
          case SEEK_SET:
          case SEEK_CUR:
                  /*
                   * Caller is responsible for adding any necessary offset
                   * when SEEK_CUR is used.
                   */
                  off = fl->l_start;
                  break;
          case SEEK_END:
                  off = np->n_size + fl->l_start;
                  break;
          default:
                  return (1);
          }
          if (fl->l_len != 0) {
                  end = off + fl->l_len;
                  if (end < off)
                          return (1);
          } else {
                  end = NFS64BITSSET;
          }
  
          error = nfscl_getcl(vp->v_mount, cred, p, false, true, &clp);
          if (error)
                  return (1);
          nfscl_filllockowner(id, own, flags);
          NFSLOCKCLSTATE();
  
          /*
           * First check the delegation locks.
           */
          dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh, np->n_fhp->nfh_len);
          if (dp != NULL) {
                  LIST_FOREACH(lp, &dp->nfsdl_lock, nfsl_list) {
                          if (!NFSBCMP(lp->nfsl_owner, own,
                              NFSV4CL_LOCKNAMELEN))
                                  break;
                  }
                  if (lp != NULL) {
                          LIST_FOREACH(lop, &lp->nfsl_lock, nfslo_list) {
                                  if (lop->nfslo_first >= end)
                                          break;
                                  if (lop->nfslo_end <= off)
                                          continue;
                                  if (lop->nfslo_type == F_WRLCK) {
                                          nfscl_clrelease(clp);
                                          NFSUNLOCKCLSTATE();
                                          return (1);
                                  }
                          }
                  }
          }
  
          /*
           * Now, check state against the server.
           */
          LIST_FOREACH(op, NFSCLOPENHASH(clp, np->n_fhp->nfh_fh,
              np->n_fhp->nfh_len), nfso_hash) {
                  if (op->nfso_fhlen == np->n_fhp->nfh_len &&
                      !NFSBCMP(op->nfso_fh, np->n_fhp->nfh_fh, op->nfso_fhlen)) {
                          LIST_FOREACH(lp, &op->nfso_lock, nfsl_list) {
                                  if (!NFSBCMP(lp->nfsl_owner, own,
                                      NFSV4CL_LOCKNAMELEN))
                                          break;
                          }
                          if (lp != NULL) {
                                  LIST_FOREACH(lop, &lp->nfsl_lock, nfslo_list) {
                                          if (lop->nfslo_first >= end)
                                                  break;
                                          if (lop->nfslo_end <= off)
                                                  continue;
                                          if (lop->nfslo_type == F_WRLCK) {
                                                  nfscl_clrelease(clp);
                                                  NFSUNLOCKCLSTATE();
                                                  return (1);
                                          }
                                  }
                          }
                  }
          }
          nfscl_clrelease(clp);
          NFSUNLOCKCLSTATE();
          return (0);
  }
  
  /*
   * Release a byte range lock owner structure.
   */
  void
  nfscl_lockrelease(struct nfscllockowner *lp, int error, int candelete)
  {
          struct nfsclclient *clp;
  
          if (lp == NULL)
                  return;
          NFSLOCKCLSTATE();
          clp = lp->nfsl_open->nfso_own->nfsow_clp;
          if (error != 0 && candelete &&
              (lp->nfsl_rwlock.nfslock_lock & NFSV4LOCK_WANTED) == 0)
                  nfscl_freelockowner(lp, 0);
          else
                  nfscl_lockunlock(&lp->nfsl_rwlock);
          nfscl_clrelease(clp);
          NFSUNLOCKCLSTATE();
  }
  
  /*
   * Unlink the open structure.
   */
  static void
  nfscl_unlinkopen(struct nfsclopen *op)
  {
  
          LIST_REMOVE(op, nfso_list);
          if (op->nfso_hash.le_prev != NULL)
                  LIST_REMOVE(op, nfso_hash);
  }
  
  /*
   * Free up an open structure and any associated byte range lock structures.
   */
  void
  nfscl_freeopen(struct nfsclopen *op, int local, bool unlink)
  {
  
          if (unlink)
                  nfscl_unlinkopen(op);
          nfscl_freealllocks(&op->nfso_lock, local);
          free(op, M_NFSCLOPEN);
          if (local)
                  nfsstatsv1.cllocalopens--;
          else
                  nfsstatsv1.clopens--;
  }
  
  /*
   * Free up all lock owners and associated locks.
   */
  static void
  nfscl_freealllocks(struct nfscllockownerhead *lhp, int local)
  {
          struct nfscllockowner *lp, *nlp;
  
          LIST_FOREACH_SAFE(lp, lhp, nfsl_list, nlp) {
                  if ((lp->nfsl_rwlock.nfslock_lock & NFSV4LOCK_WANTED))
                          panic("nfscllckw");
                  nfscl_freelockowner(lp, local);
          }
  }
  
  /*
   * Called for an Open when NFSERR_EXPIRED is received from the server.
   * If there are no byte range locks nor a Share Deny lost, try to do a
   * fresh Open. Otherwise, free the open.
   */
  static int
  nfscl_expireopen(struct nfsclclient *clp, struct nfsclopen *op,
      struct nfsmount *nmp, struct ucred *cred, NFSPROC_T *p)
  {
          struct nfscllockowner *lp;
          struct nfscldeleg *dp;
          int mustdelete = 0, error;
  
          /*
           * Look for any byte range lock(s).
           */
          LIST_FOREACH(lp, &op->nfso_lock, nfsl_list) {
                  if (!LIST_EMPTY(&lp->nfsl_lock)) {
                          mustdelete = 1;
                          break;
                  }
          }
  
          /*
           * If no byte range lock(s) nor a Share deny, try to re-open.
           */
          if (!mustdelete && (op->nfso_mode & NFSLCK_DENYBITS) == 0) {
                  newnfs_copycred(&op->nfso_cred, cred);
                  dp = NULL;
                  error = nfsrpc_reopen(nmp, op->nfso_fh,
                      op->nfso_fhlen, op->nfso_mode, op, &dp, cred, p);
                  if (error) {
                          mustdelete = 1;
                          if (dp != NULL) {
                                  free(dp, M_NFSCLDELEG);
                                  dp = NULL;
                          }
                  }
                  if (dp != NULL)
                          nfscl_deleg(nmp->nm_mountp, clp, op->nfso_fh,
                              op->nfso_fhlen, cred, p, &dp);
          }
  
          /*
           * If a byte range lock or Share deny or couldn't re-open, free it.
           */
          if (mustdelete)
                  nfscl_freeopen(op, 0, true);
          return (mustdelete);
  }
  
  /*
   * Free up an open owner structure.
   */
  static void
  nfscl_freeopenowner(struct nfsclowner *owp, int local)
  {
          int owned;
  
          /*
           * Make sure the NFSCLSTATE mutex is held, to avoid races with
           * calls in nfscl_renewthread() that do not hold a reference
           * count on the nfsclclient and just the mutex.
           * The mutex will not be held for calls done with the exclusive
           * nfsclclient lock held, in particular, nfscl_hasexpired()
           * and nfscl_recalldeleg() might do this.
           */
          owned = mtx_owned(NFSCLSTATEMUTEXPTR);
          if (owned == 0)
                  NFSLOCKCLSTATE();
          LIST_REMOVE(owp, nfsow_list);
          if (owned == 0)
                  NFSUNLOCKCLSTATE();
          free(owp, M_NFSCLOWNER);
          if (local)
                  nfsstatsv1.cllocalopenowners--;
          else
                  nfsstatsv1.clopenowners--;
  }
  
  /*
   * Free up a byte range lock owner structure.
   */
  void
  nfscl_freelockowner(struct nfscllockowner *lp, int local)
  {
          struct nfscllock *lop, *nlop;
          int owned;
  
          /*
           * Make sure the NFSCLSTATE mutex is held, to avoid races with
           * calls in nfscl_renewthread() that do not hold a reference
           * count on the nfsclclient and just the mutex.
           * The mutex will not be held for calls done with the exclusive
           * nfsclclient lock held, in particular, nfscl_hasexpired()
           * and nfscl_recalldeleg() might do this.
           */
          owned = mtx_owned(NFSCLSTATEMUTEXPTR);
          if (owned == 0)
                  NFSLOCKCLSTATE();
          LIST_REMOVE(lp, nfsl_list);
          if (owned == 0)
                  NFSUNLOCKCLSTATE();
          LIST_FOREACH_SAFE(lop, &lp->nfsl_lock, nfslo_list, nlop) {
                  nfscl_freelock(lop, local);
          }
          free(lp, M_NFSCLLOCKOWNER);
          if (local)
                  nfsstatsv1.cllocallockowners--;
          else
                  nfsstatsv1.cllockowners--;
  }
  
  /*
   * Free up a byte range lock structure.
   */
  void
  nfscl_freelock(struct nfscllock *lop, int local)
  {
  
          LIST_REMOVE(lop, nfslo_list);
          free(lop, M_NFSCLLOCK);
          if (local)
                  nfsstatsv1.cllocallocks--;
          else
                  nfsstatsv1.cllocks--;
  }
  
  /*
   * Clean out the state related to a delegation.
   */
  static void
  nfscl_cleandeleg(struct nfscldeleg *dp)
  {
          struct nfsclowner *owp, *nowp;
          struct nfsclopen *op;
  
          LIST_FOREACH_SAFE(owp, &dp->nfsdl_owner, nfsow_list, nowp) {
                  op = LIST_FIRST(&owp->nfsow_open);
                  if (op != NULL) {
                          if (LIST_NEXT(op, nfso_list) != NULL)
                                  panic("nfscleandel");
                          nfscl_freeopen(op, 1, true);
                  }
                  nfscl_freeopenowner(owp, 1);
          }
          nfscl_freealllocks(&dp->nfsdl_lock, 1);
  }
  
  /*
   * Free a delegation.
   */
  static void
  nfscl_freedeleg(struct nfscldeleghead *hdp, struct nfscldeleg *dp, bool freeit)
  {
  
          TAILQ_REMOVE(hdp, dp, nfsdl_list);
          LIST_REMOVE(dp, nfsdl_hash);
          if (freeit)
                  free(dp, M_NFSCLDELEG);
          nfsstatsv1.cldelegates--;
          nfscl_delegcnt--;
  }
  
  /*
   * Free up all state related to this client structure.
   */
  static void
  nfscl_cleanclient(struct nfsclclient *clp)
  {
          struct nfsclowner *owp, *nowp;
          struct nfsclopen *op, *nop;
          struct nfscllayout *lyp, *nlyp;
          struct nfscldevinfo *dip, *ndip;
  
          TAILQ_FOREACH_SAFE(lyp, &clp->nfsc_layout, nfsly_list, nlyp)
                  nfscl_freelayout(lyp);
  
          LIST_FOREACH_SAFE(dip, &clp->nfsc_devinfo, nfsdi_list, ndip)
                  nfscl_freedevinfo(dip);
  
          /* Now, all the OpenOwners, etc. */
          LIST_FOREACH_SAFE(owp, &clp->nfsc_owner, nfsow_list, nowp) {
                  LIST_FOREACH_SAFE(op, &owp->nfsow_open, nfso_list, nop) {
                          nfscl_freeopen(op, 0, true);
                  }
                  nfscl_freeopenowner(owp, 0);
          }
  }
  
  /*
   * Called when an NFSERR_EXPIRED is received from the server.
   */
  static void
  nfscl_expireclient(struct nfsclclient *clp, struct nfsmount *nmp,
      struct ucred *cred, NFSPROC_T *p)
  {
          struct nfsclowner *owp, *nowp, *towp;
          struct nfsclopen *op, *nop, *top;
          struct nfscldeleg *dp, *ndp;
          int ret, printed = 0;
  
          /*
           * First, merge locally issued Opens into the list for the server.
           */
          dp = TAILQ_FIRST(&clp->nfsc_deleg);
          while (dp != NULL) {
              ndp = TAILQ_NEXT(dp, nfsdl_list);
              owp = LIST_FIRST(&dp->nfsdl_owner);
              while (owp != NULL) {
                  nowp = LIST_NEXT(owp, nfsow_list);
                  op = LIST_FIRST(&owp->nfsow_open);
                  if (op != NULL) {
                      if (LIST_NEXT(op, nfso_list) != NULL)
                          panic("nfsclexp");
                      LIST_FOREACH(towp, &clp->nfsc_owner, nfsow_list) {
                          if (!NFSBCMP(towp->nfsow_owner, owp->nfsow_owner,
                              NFSV4CL_LOCKNAMELEN))
                              break;
                      }
                      if (towp != NULL) {
                          /* Merge opens in */
                          LIST_FOREACH(top, &towp->nfsow_open, nfso_list) {
                              if (top->nfso_fhlen == op->nfso_fhlen &&
                                  !NFSBCMP(top->nfso_fh, op->nfso_fh,
                                   op->nfso_fhlen)) {
                                  top->nfso_mode |= op->nfso_mode;
                                  top->nfso_opencnt += op->nfso_opencnt;
                                  break;
                              }
                          }
                          if (top == NULL) {
                              /* Just add the open to the owner list */
                              LIST_REMOVE(op, nfso_list);
                              op->nfso_own = towp;
                              LIST_INSERT_HEAD(&towp->nfsow_open, op, nfso_list);
                              LIST_INSERT_HEAD(NFSCLOPENHASH(clp, op->nfso_fh,
                                  op->nfso_fhlen), op, nfso_hash);
                              nfsstatsv1.cllocalopens--;
                              nfsstatsv1.clopens++;
                          }
                      } else {
                          /* Just add the openowner to the client list */
                          LIST_REMOVE(owp, nfsow_list);
                          owp->nfsow_clp = clp;
                          LIST_INSERT_HEAD(&clp->nfsc_owner, owp, nfsow_list);
                          LIST_INSERT_HEAD(NFSCLOPENHASH(clp, op->nfso_fh,
                              op->nfso_fhlen), op, nfso_hash);
                          nfsstatsv1.cllocalopenowners--;
                          nfsstatsv1.clopenowners++;
                          nfsstatsv1.cllocalopens--;
                          nfsstatsv1.clopens++;
                      }
                  }
                  owp = nowp;
              }
              if (!printed && !LIST_EMPTY(&dp->nfsdl_lock)) {
                  printed = 1;
                  printf("nfsv4 expired locks lost\n");
              }
              nfscl_cleandeleg(dp);
              nfscl_freedeleg(&clp->nfsc_deleg, dp, true);
              dp = ndp;
          }
          if (!TAILQ_EMPTY(&clp->nfsc_deleg))
              panic("nfsclexp");
  
          /*
           * Now, try and reopen against the server.
           */
          LIST_FOREACH_SAFE(owp, &clp->nfsc_owner, nfsow_list, nowp) {
                  owp->nfsow_seqid = 0;
                  LIST_FOREACH_SAFE(op, &owp->nfsow_open, nfso_list, nop) {
                          ret = nfscl_expireopen(clp, op, nmp, cred, p);
                          if (ret && !printed) {
                                  printed = 1;
                                  printf("nfsv4 expired locks lost\n");
                          }
                  }
                  if (LIST_EMPTY(&owp->nfsow_open))
                          nfscl_freeopenowner(owp, 0);
          }
  }
  
  /*
   * This function must be called after the process represented by "own" has
   * exited. Must be called with CLSTATE lock held.
   */
  static void
  nfscl_cleanup_common(struct nfsclclient *clp, u_int8_t *own)
  {
          struct nfsclowner *owp, *nowp;
          struct nfscllockowner *lp;
          struct nfscldeleg *dp;
  
          /* First, get rid of local locks on delegations. */
          TAILQ_FOREACH(dp, &clp->nfsc_deleg, nfsdl_list) {
                  LIST_FOREACH(lp, &dp->nfsdl_lock, nfsl_list) {
                      if (!NFSBCMP(lp->nfsl_owner, own, NFSV4CL_LOCKNAMELEN)) {
                          if ((lp->nfsl_rwlock.nfslock_lock & NFSV4LOCK_WANTED))
                              panic("nfscllckw");
                          nfscl_freelockowner(lp, 1);
                          break;
                      }
                  }
          }
          owp = LIST_FIRST(&clp->nfsc_owner);
          while (owp != NULL) {
                  nowp = LIST_NEXT(owp, nfsow_list);
                  if (!NFSBCMP(owp->nfsow_owner, own,
                      NFSV4CL_LOCKNAMELEN)) {
                          /*
                           * If there are children that haven't closed the
                           * file descriptors yet, the opens will still be
                           * here. For that case, let the renew thread clear
                           * out the OpenOwner later.
                           */
                          if (LIST_EMPTY(&owp->nfsow_open))
                                  nfscl_freeopenowner(owp, 0);
                          else
                                  owp->nfsow_defunct = 1;
                          break;
                  }
                  owp = nowp;
          }
  }
  
  /*
   * Find open/lock owners for processes that have exited.
   */
  static void
  nfscl_cleanupkext(struct nfsclclient *clp, struct nfscllockownerfhhead *lhp)
  {
          struct nfsclowner *owp, *nowp;
          struct nfsclopen *op;
          struct nfscllockowner *lp, *nlp;
          struct nfscldeleg *dp;
          uint8_t own[NFSV4CL_LOCKNAMELEN];
  
          /*
           * All the pidhash locks must be acquired, since they are sx locks
           * and must be acquired before the mutexes.  The pid(s) that will
           * be used aren't known yet, so all the locks need to be acquired.
           * Fortunately, this function is only performed once/sec.
           */
          pidhash_slockall();
          NFSLOCKCLSTATE();
          LIST_FOREACH_SAFE(owp, &clp->nfsc_owner, nfsow_list, nowp) {
                  LIST_FOREACH(op, &owp->nfsow_open, nfso_list) {
                          LIST_FOREACH_SAFE(lp, &op->nfso_lock, nfsl_list, nlp) {
                                  if (LIST_EMPTY(&lp->nfsl_lock))
                                          nfscl_emptylockowner(lp, lhp);
                          }
                  }
                  if (nfscl_procdoesntexist(owp->nfsow_owner)) {
                          memcpy(own, owp->nfsow_owner, NFSV4CL_LOCKNAMELEN);
                          nfscl_cleanup_common(clp, own);
                  }
          }
  
          /*
           * For the single open_owner case, these lock owners need to be
           * checked to see if they still exist separately.
           * This is because nfscl_procdoesntexist() never returns true for
           * the single open_owner so that the above doesn't ever call
           * nfscl_cleanup_common().
           */
          TAILQ_FOREACH(dp, &clp->nfsc_deleg, nfsdl_list) {
                  LIST_FOREACH_SAFE(lp, &dp->nfsdl_lock, nfsl_list, nlp) {
                          if (nfscl_procdoesntexist(lp->nfsl_owner)) {
                                  memcpy(own, lp->nfsl_owner,
                                      NFSV4CL_LOCKNAMELEN);
                                  nfscl_cleanup_common(clp, own);
                          }
                  }
          }
          NFSUNLOCKCLSTATE();
          pidhash_sunlockall();
  }
  
  /*
   * Take the empty lock owner and move it to the local lhp list if the
   * associated process no longer exists.
   */
  static void
  nfscl_emptylockowner(struct nfscllockowner *lp,
      struct nfscllockownerfhhead *lhp)
  {
          struct nfscllockownerfh *lfhp, *mylfhp;
          struct nfscllockowner *nlp;
          int fnd_it;
  
          /* If not a Posix lock owner, just return. */
          if ((lp->nfsl_lockflags & F_POSIX) == 0)
                  return;
  
          fnd_it = 0;
          mylfhp = NULL;
          /*
           * First, search to see if this lock owner is already in the list.
           * If it is, then the associated process no longer exists.
           */
          SLIST_FOREACH(lfhp, lhp, nfslfh_list) {
                  if (lfhp->nfslfh_len == lp->nfsl_open->nfso_fhlen &&
                      !NFSBCMP(lfhp->nfslfh_fh, lp->nfsl_open->nfso_fh,
                      lfhp->nfslfh_len))
                          mylfhp = lfhp;
                  LIST_FOREACH(nlp, &lfhp->nfslfh_lock, nfsl_list)
                          if (!NFSBCMP(nlp->nfsl_owner, lp->nfsl_owner,
                              NFSV4CL_LOCKNAMELEN))
                                  fnd_it = 1;
          }
          /* If not found, check if process still exists. */
          if (fnd_it == 0 && nfscl_procdoesntexist(lp->nfsl_owner) == 0)
                  return;
  
          /* Move the lock owner over to the local list. */
          if (mylfhp == NULL) {
                  mylfhp = malloc(sizeof(struct nfscllockownerfh), M_TEMP,
                      M_NOWAIT);
                  if (mylfhp == NULL)
                          return;
                  mylfhp->nfslfh_len = lp->nfsl_open->nfso_fhlen;
                  NFSBCOPY(lp->nfsl_open->nfso_fh, mylfhp->nfslfh_fh,
                      mylfhp->nfslfh_len);
                  LIST_INIT(&mylfhp->nfslfh_lock);
                  SLIST_INSERT_HEAD(lhp, mylfhp, nfslfh_list);
          }
          LIST_REMOVE(lp, nfsl_list);
          LIST_INSERT_HEAD(&mylfhp->nfslfh_lock, lp, nfsl_list);
  }
  
  static int      fake_global;    /* Used to force visibility of MNTK_UNMOUNTF */
  /*
   * Called from nfs umount to free up the clientid.
   */
  void
  nfscl_umount(struct nfsmount *nmp, NFSPROC_T *p, struct nfscldeleghead *dhp)
  {
          struct nfsclclient *clp;
          struct ucred *cred;
          int igotlock;
  
          /*
           * For the case that matters, this is the thread that set
           * MNTK_UNMOUNTF, so it will see it set. The code that follows is
           * done to ensure that any thread executing nfscl_getcl() after
           * this time, will see MNTK_UNMOUNTF set. nfscl_getcl() uses the
           * mutex for NFSLOCKCLSTATE(), so it is "m" for the following
           * explanation, courtesy of Alan Cox.
           * What follows is a snippet from Alan Cox's email at:
           * https://docs.FreeBSD.org/cgi/mid.cgi?BANLkTikR3d65zPHo9==08ZfJ2vmqZucEvw
           * 
           * 1. Set MNTK_UNMOUNTF
           * 2. Acquire a standard FreeBSD mutex "m".
           * 3. Update some data structures.
           * 4. Release mutex "m".
           * 
           * Then, other threads that acquire "m" after step 4 has occurred will
           * see MNTK_UNMOUNTF as set.  But, other threads that beat thread X to
           * step 2 may or may not see MNTK_UNMOUNTF as set.
           */
          NFSLOCKCLSTATE();
          if ((nmp->nm_mountp->mnt_kern_flag & MNTK_UNMOUNTF) != 0) {
                  fake_global++;
                  NFSUNLOCKCLSTATE();
                  NFSLOCKCLSTATE();
          }
  
          clp = nmp->nm_clp;
          if (clp != NULL) {
                  if ((clp->nfsc_flags & NFSCLFLAGS_INITED) == 0)
                          panic("nfscl umount");
  
                  /*
                   * First, handshake with the nfscl renew thread, to terminate
                   * it.
                   */
                  clp->nfsc_flags |= NFSCLFLAGS_UMOUNT;
                  while (clp->nfsc_flags & NFSCLFLAGS_HASTHREAD)
                          (void)mtx_sleep(clp, NFSCLSTATEMUTEXPTR, PWAIT,
                              "nfsclumnt", hz);
  
                  /*
                   * Now, get the exclusive lock on the client state, so
                   * that no uses of the state are still in progress.
                   */
                  do {
                          igotlock = nfsv4_lock(&clp->nfsc_lock, 1, NULL,
                              NFSCLSTATEMUTEXPTR, NULL);
                  } while (!igotlock);
                  NFSUNLOCKCLSTATE();
  
                  /*
                   * Free up all the state. It will expire on the server, but
                   * maybe we should do a SetClientId/SetClientIdConfirm so
                   * the server throws it away?
                   */
                  LIST_REMOVE(clp, nfsc_list);
                  nfscl_delegreturnall(clp, p, dhp);
                  cred = newnfs_getcred();
                  if (NFSHASNFSV4N(nmp)) {
                          nfsrpc_destroysession(nmp, NULL, cred, p);
                          nfsrpc_destroyclient(nmp, clp, cred, p);
                  } else
                          nfsrpc_setclient(nmp, clp, 0, NULL, cred, p);
                  nfscl_cleanclient(clp);
                  nmp->nm_clp = NULL;
                  NFSFREECRED(cred);
                  free(clp, M_NFSCLCLIENT);
          } else
                  NFSUNLOCKCLSTATE();
  }
  
  /*
   * This function is called when a server replies with NFSERR_STALECLIENTID
   * NFSERR_STALESTATEID or NFSERR_BADSESSION. It traverses the clientid lists,
   * doing Opens and Locks with reclaim. If these fail, it deletes the
   * corresponding state.
   */
  static void
  nfscl_recover(struct nfsclclient *clp, bool *retokp, struct ucred *cred,
      NFSPROC_T *p)
  {
          struct nfsclowner *owp, *nowp;
          struct nfsclopen *op, *nop;
          struct nfscllockowner *lp, *nlp;
          struct nfscllock *lop, *nlop;
          struct nfscldeleg *dp, *ndp, *tdp;
          struct nfsmount *nmp;
          struct ucred *tcred;
          struct nfsclopenhead extra_open;
          struct nfscldeleghead extra_deleg;
          struct nfsreq *rep;
          u_int64_t len;
          u_int32_t delegtype = NFSV4OPEN_DELEGATEWRITE, mode;
          int i, igotlock = 0, error, trycnt, firstlock;
          struct nfscllayout *lyp, *nlyp;
          bool recovered_one;
  
          /*
           * First, lock the client structure, so everyone else will
           * block when trying to use state.
           */
          NFSLOCKCLSTATE();
          clp->nfsc_flags |= NFSCLFLAGS_RECVRINPROG;
          do {
                  igotlock = nfsv4_lock(&clp->nfsc_lock, 1, NULL,
                      NFSCLSTATEMUTEXPTR, NULL);
          } while (!igotlock);
          NFSUNLOCKCLSTATE();
  
          nmp = clp->nfsc_nmp;
          if (nmp == NULL)
                  panic("nfscl recover");
  
          /*
           * For now, just get rid of all layouts. There may be a need
           * to do LayoutCommit Ops with reclaim == true later.
           */
          TAILQ_FOREACH_SAFE(lyp, &clp->nfsc_layout, nfsly_list, nlyp)
                  nfscl_freelayout(lyp);
          TAILQ_INIT(&clp->nfsc_layout);
          for (i = 0; i < NFSCLLAYOUTHASHSIZE; i++)
                  LIST_INIT(&clp->nfsc_layouthash[i]);
  
          trycnt = 5;
          tcred = NULL;
          do {
                  error = nfsrpc_setclient(nmp, clp, 1, retokp, cred, p);
          } while ((error == NFSERR_STALECLIENTID ||
               error == NFSERR_BADSESSION ||
               error == NFSERR_STALEDONTRECOVER) && --trycnt > 0);
          if (error) {
                  NFSLOCKCLSTATE();
                  clp->nfsc_flags &= ~(NFSCLFLAGS_RECOVER |
                      NFSCLFLAGS_RECVRINPROG);
                  wakeup(&clp->nfsc_flags);
                  nfsv4_unlock(&clp->nfsc_lock, 0);
                  NFSUNLOCKCLSTATE();
                  return;
          }
          clp->nfsc_flags |= NFSCLFLAGS_HASCLIENTID;
          clp->nfsc_flags &= ~NFSCLFLAGS_RECOVER;
  
          /*
           * Mark requests already queued on the server, so that they don't
           * initiate another recovery cycle. Any requests already in the
           * queue that handle state information will have the old stale
           * clientid/stateid and will get a NFSERR_STALESTATEID,
           * NFSERR_STALECLIENTID or NFSERR_BADSESSION reply from the server.
           * This will be translated to NFSERR_STALEDONTRECOVER when
           * R_DONTRECOVER is set.
           */
          NFSLOCKREQ();
          TAILQ_FOREACH(rep, &nfsd_reqq, r_chain) {
                  if (rep->r_nmp == nmp)
                          rep->r_flags |= R_DONTRECOVER;
          }
          NFSUNLOCKREQ();
  
          /*
           * If nfsrpc_setclient() returns *retokp == true,
           * no more recovery is needed.
           */
          if (*retokp)
                  goto out;
  
          /*
           * Now, mark all delegations "need reclaim".
           */
          TAILQ_FOREACH(dp, &clp->nfsc_deleg, nfsdl_list)
                  dp->nfsdl_flags |= NFSCLDL_NEEDRECLAIM;
  
          TAILQ_INIT(&extra_deleg);
          LIST_INIT(&extra_open);
          /*
           * Now traverse the state lists, doing Open and Lock Reclaims.
           */
          tcred = newnfs_getcred();
          recovered_one = false;
          owp = LIST_FIRST(&clp->nfsc_owner);
          while (owp != NULL) {
              nowp = LIST_NEXT(owp, nfsow_list);
              owp->nfsow_seqid = 0;
              op = LIST_FIRST(&owp->nfsow_open);
              while (op != NULL) {
                  nop = LIST_NEXT(op, nfso_list);
                  if (error != NFSERR_NOGRACE && error != NFSERR_BADSESSION) {
                      /* Search for a delegation to reclaim with the open */
                      TAILQ_FOREACH(dp, &clp->nfsc_deleg, nfsdl_list) {
                          if (!(dp->nfsdl_flags & NFSCLDL_NEEDRECLAIM))
                              continue;
                          if ((dp->nfsdl_flags & NFSCLDL_WRITE)) {
                              mode = NFSV4OPEN_ACCESSWRITE;
                              delegtype = NFSV4OPEN_DELEGATEWRITE;
                          } else {
                              mode = NFSV4OPEN_ACCESSREAD;
                              delegtype = NFSV4OPEN_DELEGATEREAD;
                          }
                          if ((op->nfso_mode & mode) == mode &&
                              op->nfso_fhlen == dp->nfsdl_fhlen &&
                              !NFSBCMP(op->nfso_fh, dp->nfsdl_fh, op->nfso_fhlen))
                              break;
                      }
                      ndp = dp;
                      if (dp == NULL)
                          delegtype = NFSV4OPEN_DELEGATENONE;
                      newnfs_copycred(&op->nfso_cred, tcred);
                      error = nfscl_tryopen(nmp, NULL, op->nfso_fh,
                          op->nfso_fhlen, op->nfso_fh, op->nfso_fhlen,
                          op->nfso_mode, op, NULL, 0, &ndp, 1, delegtype,
                          tcred, p);
                      if (!error) {
                          recovered_one = true;
                          /* Handle any replied delegation */
                          if (ndp != NULL && ((ndp->nfsdl_flags & NFSCLDL_WRITE)
                              || NFSMNT_RDONLY(nmp->nm_mountp))) {
                              if ((ndp->nfsdl_flags & NFSCLDL_WRITE))
                                  mode = NFSV4OPEN_ACCESSWRITE;
                              else
                                  mode = NFSV4OPEN_ACCESSREAD;
                              TAILQ_FOREACH(dp, &clp->nfsc_deleg, nfsdl_list) {
                                  if (!(dp->nfsdl_flags & NFSCLDL_NEEDRECLAIM))
                                      continue;
                                  if ((op->nfso_mode & mode) == mode &&
                                      op->nfso_fhlen == dp->nfsdl_fhlen &&
                                      !NFSBCMP(op->nfso_fh, dp->nfsdl_fh,
                                      op->nfso_fhlen)) {
                                      dp->nfsdl_stateid = ndp->nfsdl_stateid;
                                      dp->nfsdl_sizelimit = ndp->nfsdl_sizelimit;
                                      dp->nfsdl_ace = ndp->nfsdl_ace;
                                      dp->nfsdl_change = ndp->nfsdl_change;
                                      dp->nfsdl_flags &= ~NFSCLDL_NEEDRECLAIM;
                                      if ((ndp->nfsdl_flags & NFSCLDL_RECALL))
                                          dp->nfsdl_flags |= NFSCLDL_RECALL;
                                      free(ndp, M_NFSCLDELEG);
                                      ndp = NULL;
                                      break;
                                  }
                              }
                          }
                          if (ndp != NULL)
                              TAILQ_INSERT_HEAD(&extra_deleg, ndp, nfsdl_list);
  
                          /* and reclaim all byte range locks */
                          lp = LIST_FIRST(&op->nfso_lock);
                          while (lp != NULL) {
                              nlp = LIST_NEXT(lp, nfsl_list);
                              lp->nfsl_seqid = 0;
                              firstlock = 1;
                              lop = LIST_FIRST(&lp->nfsl_lock);
                              while (lop != NULL) {
                                  nlop = LIST_NEXT(lop, nfslo_list);
                                  if (lop->nfslo_end == NFS64BITSSET)
                                      len = NFS64BITSSET;
                                  else
                                      len = lop->nfslo_end - lop->nfslo_first;
                                  error = nfscl_trylock(nmp, NULL,
                                      op->nfso_fh, op->nfso_fhlen, lp,
                                      firstlock, 1, lop->nfslo_first, len,
                                      lop->nfslo_type, tcred, p);
                                  if (error != 0)
                                      nfscl_freelock(lop, 0);
                                  else
                                      firstlock = 0;
                                  lop = nlop;
                              }
                              /* If no locks, but a lockowner, just delete it. */
                              if (LIST_EMPTY(&lp->nfsl_lock))
                                  nfscl_freelockowner(lp, 0);
                              lp = nlp;
                          }
                      } else if (error == NFSERR_NOGRACE && !recovered_one &&
                          NFSHASNFSV4N(nmp)) {
                          /*
                           * For NFSv4.1/4.2, the NFSERR_EXPIRED case will
                           * actually end up here, since the client will do
                           * a recovery for NFSERR_BADSESSION, but will get
                           * an NFSERR_NOGRACE reply for the first "reclaim"
                           * attempt.
                           * So, call nfscl_expireclient() to recover the
                           * opens as best we can and then do a reclaim
                           * complete and return.
                           */
                          nfsrpc_reclaimcomplete(nmp, cred, p);
                          nfscl_expireclient(clp, nmp, tcred, p);
                          goto out;
                      }
                  }
                  if (error != 0 && error != NFSERR_BADSESSION)
                      nfscl_freeopen(op, 0, true);
                  op = nop;
              }
              owp = nowp;
          }
  
          /*
           * Now, try and get any delegations not yet reclaimed by cobbling
           * to-gether an appropriate open.
           */
          nowp = NULL;
          dp = TAILQ_FIRST(&clp->nfsc_deleg);
          while (dp != NULL) {
              ndp = TAILQ_NEXT(dp, nfsdl_list);
              if ((dp->nfsdl_flags & NFSCLDL_NEEDRECLAIM)) {
                  if (nowp == NULL) {
                      nowp = malloc(
                          sizeof (struct nfsclowner), M_NFSCLOWNER, M_WAITOK);
                      /*
                       * Name must be as long an largest possible
                       * NFSV4CL_LOCKNAMELEN. 12 for now.
                       */
                      NFSBCOPY("RECLAIMDELEG", nowp->nfsow_owner,
                          NFSV4CL_LOCKNAMELEN);
                      LIST_INIT(&nowp->nfsow_open);
                      nowp->nfsow_clp = clp;
                      nowp->nfsow_seqid = 0;
                      nowp->nfsow_defunct = 0;
                      nfscl_lockinit(&nowp->nfsow_rwlock);
                  }
                  nop = NULL;
                  if (error != NFSERR_NOGRACE && error != NFSERR_BADSESSION) {
                      nop = malloc(sizeof (struct nfsclopen) +
                          dp->nfsdl_fhlen - 1, M_NFSCLOPEN, M_WAITOK);
                      nop->nfso_own = nowp;
                      if ((dp->nfsdl_flags & NFSCLDL_WRITE)) {
                          nop->nfso_mode = NFSV4OPEN_ACCESSWRITE;
                          delegtype = NFSV4OPEN_DELEGATEWRITE;
                      } else {
                          nop->nfso_mode = NFSV4OPEN_ACCESSREAD;
                          delegtype = NFSV4OPEN_DELEGATEREAD;
                      }
                      nop->nfso_opencnt = 0;
                      nop->nfso_posixlock = 1;
                      nop->nfso_fhlen = dp->nfsdl_fhlen;
                      NFSBCOPY(dp->nfsdl_fh, nop->nfso_fh, dp->nfsdl_fhlen);
                      LIST_INIT(&nop->nfso_lock);
                      nop->nfso_stateid.seqid = 0;
                      nop->nfso_stateid.other[0] = 0;
                      nop->nfso_stateid.other[1] = 0;
                      nop->nfso_stateid.other[2] = 0;
                      newnfs_copycred(&dp->nfsdl_cred, tcred);
                      newnfs_copyincred(tcred, &nop->nfso_cred);
                      tdp = NULL;
                      error = nfscl_tryopen(nmp, NULL, nop->nfso_fh,
                          nop->nfso_fhlen, nop->nfso_fh, nop->nfso_fhlen,
                          nop->nfso_mode, nop, NULL, 0, &tdp, 1,
                          delegtype, tcred, p);
                      if (tdp != NULL) {
                          if ((tdp->nfsdl_flags & NFSCLDL_WRITE))
                              mode = NFSV4OPEN_ACCESSWRITE;
                          else
                              mode = NFSV4OPEN_ACCESSREAD;
                          if ((nop->nfso_mode & mode) == mode &&
                              nop->nfso_fhlen == tdp->nfsdl_fhlen &&
                              !NFSBCMP(nop->nfso_fh, tdp->nfsdl_fh,
                              nop->nfso_fhlen)) {
                              dp->nfsdl_stateid = tdp->nfsdl_stateid;
                              dp->nfsdl_sizelimit = tdp->nfsdl_sizelimit;
                              dp->nfsdl_ace = tdp->nfsdl_ace;
                              dp->nfsdl_change = tdp->nfsdl_change;
                              dp->nfsdl_flags &= ~NFSCLDL_NEEDRECLAIM;
                              if ((tdp->nfsdl_flags & NFSCLDL_RECALL))
                                  dp->nfsdl_flags |= NFSCLDL_RECALL;
                              free(tdp, M_NFSCLDELEG);
                          } else {
                              TAILQ_INSERT_HEAD(&extra_deleg, tdp, nfsdl_list);
                          }
                      }
                  }
                  if (error) {
                      if (nop != NULL)
                          free(nop, M_NFSCLOPEN);
                      if (error == NFSERR_NOGRACE && !recovered_one &&
                          NFSHASNFSV4N(nmp)) {
                          /*
                           * For NFSv4.1/4.2, the NFSERR_EXPIRED case will
                           * actually end up here, since the client will do
                           * a recovery for NFSERR_BADSESSION, but will get
                           * an NFSERR_NOGRACE reply for the first "reclaim"
                           * attempt.
                           * So, call nfscl_expireclient() to recover the
                           * opens as best we can and then do a reclaim
                           * complete and return.
                           */
                          nfsrpc_reclaimcomplete(nmp, cred, p);
                          nfscl_expireclient(clp, nmp, tcred, p);
                          free(nowp, M_NFSCLOWNER);
                          goto out;
                      }
                      /*
                       * Couldn't reclaim it, so throw the state
                       * away. Ouch!!
                       */
                      nfscl_cleandeleg(dp);
                      nfscl_freedeleg(&clp->nfsc_deleg, dp, true);
                  } else {
                      recovered_one = true;
                      LIST_INSERT_HEAD(&extra_open, nop, nfso_list);
                  }
              }
              dp = ndp;
          }
  
          /*
           * Now, get rid of extra Opens and Delegations.
           */
          LIST_FOREACH_SAFE(op, &extra_open, nfso_list, nop) {
                  do {
                          newnfs_copycred(&op->nfso_cred, tcred);
                          error = nfscl_tryclose(op, tcred, nmp, p, true);
                          if (error == NFSERR_GRACE)
                                  (void) nfs_catnap(PZERO, error, "nfsexcls");
                  } while (error == NFSERR_GRACE);
                  LIST_REMOVE(op, nfso_list);
                  free(op, M_NFSCLOPEN);
          }
          if (nowp != NULL)
                  free(nowp, M_NFSCLOWNER);
  
          TAILQ_FOREACH_SAFE(dp, &extra_deleg, nfsdl_list, ndp) {
                  do {
                          newnfs_copycred(&dp->nfsdl_cred, tcred);
                          error = nfscl_trydelegreturn(dp, tcred, nmp, p);
                          if (error == NFSERR_GRACE)
                                  (void) nfs_catnap(PZERO, error, "nfsexdlg");
                  } while (error == NFSERR_GRACE);
                  TAILQ_REMOVE(&extra_deleg, dp, nfsdl_list);
                  free(dp, M_NFSCLDELEG);
          }
  
          /* For NFSv4.1 or later, do a RECLAIM_COMPLETE. */
          if (NFSHASNFSV4N(nmp))
                  (void)nfsrpc_reclaimcomplete(nmp, cred, p);
  
  out:
          NFSLOCKCLSTATE();
          clp->nfsc_flags &= ~NFSCLFLAGS_RECVRINPROG;
          wakeup(&clp->nfsc_flags);
          nfsv4_unlock(&clp->nfsc_lock, 0);
          NFSUNLOCKCLSTATE();
          if (tcred != NULL)
                  NFSFREECRED(tcred);
  }
  
  /*
   * This function is called when a server replies with NFSERR_EXPIRED.
   * It deletes all state for the client and does a fresh SetClientId/confirm.
   * XXX Someday it should post a signal to the process(es) that hold the
   * state, so they know that lock state has been lost.
   */
  int
  nfscl_hasexpired(struct nfsclclient *clp, u_int32_t clidrev, NFSPROC_T *p)
  {
          struct nfsmount *nmp;
          struct ucred *cred;
          int igotlock = 0, error, trycnt;
  
          /*
           * If the clientid has gone away or a new SetClientid has already
           * been done, just return ok.
           */
          if (clp == NULL || clidrev != clp->nfsc_clientidrev)
                  return (0);
  
          /*
           * First, lock the client structure, so everyone else will
           * block when trying to use state. Also, use NFSCLFLAGS_EXPIREIT so
           * that only one thread does the work.
           */
          NFSLOCKCLSTATE();
          clp->nfsc_flags |= NFSCLFLAGS_EXPIREIT;
          do {
                  igotlock = nfsv4_lock(&clp->nfsc_lock, 1, NULL,
                      NFSCLSTATEMUTEXPTR, NULL);
          } while (!igotlock && (clp->nfsc_flags & NFSCLFLAGS_EXPIREIT));
          if ((clp->nfsc_flags & NFSCLFLAGS_EXPIREIT) == 0) {
                  if (igotlock)
                          nfsv4_unlock(&clp->nfsc_lock, 0);
                  NFSUNLOCKCLSTATE();
                  return (0);
          }
          clp->nfsc_flags |= NFSCLFLAGS_RECVRINPROG;
          NFSUNLOCKCLSTATE();
  
          nmp = clp->nfsc_nmp;
          if (nmp == NULL)
                  panic("nfscl expired");
          cred = newnfs_getcred();
          trycnt = 5;
          do {
                  error = nfsrpc_setclient(nmp, clp, 0, NULL, cred, p);
          } while ((error == NFSERR_STALECLIENTID ||
               error == NFSERR_BADSESSION ||
               error == NFSERR_STALEDONTRECOVER) && --trycnt > 0);
          if (error) {
                  NFSLOCKCLSTATE();
                  clp->nfsc_flags &= ~NFSCLFLAGS_RECOVER;
          } else {
                  /*
                   * Expire the state for the client.
                   */
                  nfscl_expireclient(clp, nmp, cred, p);
                  NFSLOCKCLSTATE();
                  clp->nfsc_flags |= NFSCLFLAGS_HASCLIENTID;
                  clp->nfsc_flags &= ~NFSCLFLAGS_RECOVER;
          }
          clp->nfsc_flags &= ~(NFSCLFLAGS_EXPIREIT | NFSCLFLAGS_RECVRINPROG);
          wakeup(&clp->nfsc_flags);
          nfsv4_unlock(&clp->nfsc_lock, 0);
          NFSUNLOCKCLSTATE();
          NFSFREECRED(cred);
          return (error);
  }
  
  /*
   * This function inserts a lock in the list after insert_lop.
   */
  static void
  nfscl_insertlock(struct nfscllockowner *lp, struct nfscllock *new_lop,
      struct nfscllock *insert_lop, int local)
  {
  
          if ((struct nfscllockowner *)insert_lop == lp)
                  LIST_INSERT_HEAD(&lp->nfsl_lock, new_lop, nfslo_list);
          else
                  LIST_INSERT_AFTER(insert_lop, new_lop, nfslo_list);
          if (local)
                  nfsstatsv1.cllocallocks++;
          else
                  nfsstatsv1.cllocks++;
  }
  
  /*
   * 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 NFSCLLOCK_READ or NFSCLLOCK_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.
   * Returns 1 if the locks were modified, 0 otherwise.
   */
  static int
  nfscl_updatelock(struct nfscllockowner *lp, struct nfscllock **new_lopp,
      struct nfscllock **other_lopp, int local)
  {
          struct nfscllock *new_lop = *new_lopp;
          struct nfscllock *lop, *tlop, *ilop;
          struct nfscllock *other_lop;
          int unlock = 0, modified = 0;
          u_int64_t tmp;
  
          /*
           * Work down the list until the lock is merged.
           */
          if (new_lop->nfslo_type == F_UNLCK)
                  unlock = 1;
          ilop = (struct nfscllock *)lp;
          lop = LIST_FIRST(&lp->nfsl_lock);
          while (lop != NULL) {
              /*
               * Only check locks for this file that aren't before the start of
               * new lock's range.
               */
              if (lop->nfslo_end >= new_lop->nfslo_first) {
                  if (new_lop->nfslo_end < lop->nfslo_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->nfslo_type == lop->nfslo_type ||
                      (new_lop->nfslo_first <= lop->nfslo_first &&
                       new_lop->nfslo_end >= lop->nfslo_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 (new_lop->nfslo_type != lop->nfslo_type ||
                          new_lop->nfslo_first != lop->nfslo_first ||
                          new_lop->nfslo_end != lop->nfslo_end)
                          modified = 1;
                      if (lop->nfslo_first < new_lop->nfslo_first)
                          new_lop->nfslo_first = lop->nfslo_first;
                      if (lop->nfslo_end > new_lop->nfslo_end)
                          new_lop->nfslo_end = lop->nfslo_end;
                      tlop = lop;
                      lop = LIST_NEXT(lop, nfslo_list);
                      nfscl_freelock(tlop, local);
                      continue;
                  }
  
                  /*
                   * All these cases are for contiguous locks that are not the
                   * same type, so they can't be merged.
                   */
                  if (new_lop->nfslo_first <= lop->nfslo_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.)
                       */
                      if (lop->nfslo_first != new_lop->nfslo_end) {
                          lop->nfslo_first = new_lop->nfslo_end;
                          modified = 1;
                      }
                      break;
                  }
                  if (new_lop->nfslo_end >= lop->nfslo_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.
                       */
                      if (lop->nfslo_end != new_lop->nfslo_first) {
                          lop->nfslo_end = new_lop->nfslo_first;
                          modified = 1;
                      }
                      ilop = lop;
                      lop = LIST_NEXT(lop, nfslo_list);
                      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->nfslo_type any longer.
                   */
                  tmp = new_lop->nfslo_first;
                  if (unlock) {
                      other_lop = new_lop;
                      *new_lopp = NULL;
                  } else {
                      other_lop = *other_lopp;
                      *other_lopp = NULL;
                  }
                  other_lop->nfslo_first = new_lop->nfslo_end;
                  other_lop->nfslo_end = lop->nfslo_end;
                  other_lop->nfslo_type = lop->nfslo_type;
                  lop->nfslo_end = tmp;
                  nfscl_insertlock(lp, other_lop, lop, local);
                  ilop = lop;
                  modified = 1;
                  break;
              }
              ilop = lop;
              lop = LIST_NEXT(lop, nfslo_list);
              if (lop == NULL)
                  break;
          }
  
          /*
           * Insert the new lock in the list at the appropriate place.
           */
          if (!unlock) {
                  nfscl_insertlock(lp, new_lop, ilop, local);
                  *new_lopp = NULL;
                  modified = 1;
          }
          return (modified);
  }
  
  /*
   * This function must be run as a kernel thread.
   * It does Renew Ops and recovery, when required.
   */
  void
  nfscl_renewthread(struct nfsclclient *clp, NFSPROC_T *p)
  {
          struct nfsclowner *owp, *nowp;
          struct nfsclopen *op;
          struct nfscllockowner *lp, *nlp;
          struct nfscldeleghead dh;
          struct nfscldeleg *dp, *ndp;
          struct ucred *cred;
          u_int32_t clidrev;
          int error, cbpathdown, islept, igotlock, ret, clearok;
          uint32_t recover_done_time = 0;
          time_t mytime;
          static time_t prevsec = 0;
          struct nfscllockownerfh *lfhp, *nlfhp;
          struct nfscllockownerfhhead lfh;
          struct nfscllayout *lyp, *nlyp;
          struct nfscldevinfo *dip, *ndip;
          struct nfscllayouthead rlh;
          struct nfsclrecalllayout *recallp;
          struct nfsclds *dsp;
          bool retok;
          struct mount *mp;
          vnode_t vp;
  
          cred = newnfs_getcred();
          NFSLOCKCLSTATE();
          clp->nfsc_flags |= NFSCLFLAGS_HASTHREAD;
          mp = clp->nfsc_nmp->nm_mountp;
          NFSUNLOCKCLSTATE();
          for(;;) {
                  newnfs_setroot(cred);
                  cbpathdown = 0;
                  if (clp->nfsc_flags & NFSCLFLAGS_RECOVER) {
                          /*
                           * Only allow one full recover within 1/2 of the lease
                           * duration (nfsc_renew).
                           * retok is value/result.  If passed in set to true,
                           * it indicates only a CreateSession operation should
                           * be attempted.
                           * If it is returned true, it indicates that the
                           * recovery only required a CreateSession.
                           */
                          retok = true;
                          if (recover_done_time < NFSD_MONOSEC) {
                                  recover_done_time = NFSD_MONOSEC +
                                      clp->nfsc_renew;
                                  retok = false;
                          }
                          NFSCL_DEBUG(1, "Doing recovery, only "
                              "createsession=%d\n", retok);
                          nfscl_recover(clp, &retok, cred, p);
                  }
                  if (clp->nfsc_expire <= NFSD_MONOSEC &&
                      (clp->nfsc_flags & NFSCLFLAGS_HASCLIENTID)) {
                          clp->nfsc_expire = NFSD_MONOSEC + clp->nfsc_renew;
                          clidrev = clp->nfsc_clientidrev;
                          error = nfsrpc_renew(clp, NULL, cred, p);
                          if (error == NFSERR_CBPATHDOWN)
                              cbpathdown = 1;
                          else if (error == NFSERR_STALECLIENTID) {
                              NFSLOCKCLSTATE();
                              clp->nfsc_flags |= NFSCLFLAGS_RECOVER;
                              NFSUNLOCKCLSTATE();
                          } else if (error == NFSERR_EXPIRED)
                              (void) nfscl_hasexpired(clp, clidrev, p);
                  }
  
  checkdsrenew:
                  if (NFSHASNFSV4N(clp->nfsc_nmp)) {
                          /* Do renews for any DS sessions. */
                          NFSLOCKMNT(clp->nfsc_nmp);
                          /* Skip first entry, since the MDS is handled above. */
                          dsp = TAILQ_FIRST(&clp->nfsc_nmp->nm_sess);
                          if (dsp != NULL)
                                  dsp = TAILQ_NEXT(dsp, nfsclds_list);
                          while (dsp != NULL) {
                                  if (dsp->nfsclds_expire <= NFSD_MONOSEC &&
                                      dsp->nfsclds_sess.nfsess_defunct == 0) {
                                          dsp->nfsclds_expire = NFSD_MONOSEC +
                                              clp->nfsc_renew;
                                          NFSUNLOCKMNT(clp->nfsc_nmp);
                                          (void)nfsrpc_renew(clp, dsp, cred, p);
                                          goto checkdsrenew;
                                  }
                                  dsp = TAILQ_NEXT(dsp, nfsclds_list);
                          }
                          NFSUNLOCKMNT(clp->nfsc_nmp);
                  }
  
                  TAILQ_INIT(&dh);
                  NFSLOCKCLSTATE();
                  if (cbpathdown)
                          /* It's a Total Recall! */
                          nfscl_totalrecall(clp);
  
                  /*
                   * Now, handle defunct owners.
                   */
                  LIST_FOREACH_SAFE(owp, &clp->nfsc_owner, nfsow_list, nowp) {
                          if (LIST_EMPTY(&owp->nfsow_open)) {
                                  if (owp->nfsow_defunct != 0)
                                          nfscl_freeopenowner(owp, 0);
                          }
                  }
  
                  /*
                   * Do the recall on any delegations. To avoid trouble, always
                   * come back up here after having slept.
                   */
                  igotlock = 0;
  tryagain:
                  dp = TAILQ_FIRST(&clp->nfsc_deleg);
                  while (dp != NULL) {
                          ndp = TAILQ_NEXT(dp, nfsdl_list);
                          if ((dp->nfsdl_flags & NFSCLDL_RECALL)) {
                                  /*
                                   * Wait for outstanding I/O ops to be done.
                                   */
                                  if (dp->nfsdl_rwlock.nfslock_usecnt > 0) {
                                      if (igotlock) {
                                          nfsv4_unlock(&clp->nfsc_lock, 0);
                                          igotlock = 0;
                                      }
                                      dp->nfsdl_rwlock.nfslock_lock |=
                                          NFSV4LOCK_WANTED;
                                      msleep(&dp->nfsdl_rwlock,
                                          NFSCLSTATEMUTEXPTR, PVFS, "nfscld",
                                          5 * hz);
                                      if (NFSCL_FORCEDISM(mp))
                                          goto terminate;
                                      goto tryagain;
                                  }
                                  while (!igotlock) {
                                      igotlock = nfsv4_lock(&clp->nfsc_lock, 1,
                                          &islept, NFSCLSTATEMUTEXPTR, mp);
                                      if (igotlock == 0 && NFSCL_FORCEDISM(mp))
                                          goto terminate;
                                      if (islept)
                                          goto tryagain;
                                  }
                                  NFSUNLOCKCLSTATE();
                                  newnfs_copycred(&dp->nfsdl_cred, cred);
                                  ret = nfscl_recalldeleg(clp, clp->nfsc_nmp, dp,
                                      NULL, cred, p, 1, &vp);
                                  if (!ret) {
                                      nfscl_cleandeleg(dp);
                                      TAILQ_REMOVE(&clp->nfsc_deleg, dp,
                                          nfsdl_list);
                                      LIST_REMOVE(dp, nfsdl_hash);
                                      TAILQ_INSERT_HEAD(&dh, dp, nfsdl_list);
                                      nfscl_delegcnt--;
                                      nfsstatsv1.cldelegates--;
                                  }
                                  NFSLOCKCLSTATE();
                                  /*
                                   * The nfsc_lock must be released before doing
                                   * vrele(), since it might call nfs_inactive().
                                   * For the unlikely case where the vnode failed
                                   * to be acquired by nfscl_recalldeleg(), a
                                   * VOP_RECLAIM() should be in progress and it
                                   * will return the delegation.
                                   */
                                  nfsv4_unlock(&clp->nfsc_lock, 0);
                                  igotlock = 0;
                                  if (vp != NULL) {
                                          NFSUNLOCKCLSTATE();
                                          vrele(vp);
                                          NFSLOCKCLSTATE();
                                  }
                                  goto tryagain;
                          }
                          dp = ndp;
                  }
  
                  /*
                   * Clear out old delegations, if we are above the high water
                   * mark. Only clear out ones with no state related to them.
                   * The tailq list is in LRU order.
                   */
                  dp = TAILQ_LAST(&clp->nfsc_deleg, nfscldeleghead);
                  while (nfscl_delegcnt > nfscl_deleghighwater && dp != NULL) {
                      ndp = TAILQ_PREV(dp, nfscldeleghead, nfsdl_list);
                      if (dp->nfsdl_rwlock.nfslock_usecnt == 0 &&
                          dp->nfsdl_rwlock.nfslock_lock == 0 &&
                          dp->nfsdl_timestamp < NFSD_MONOSEC &&
                          (dp->nfsdl_flags & (NFSCLDL_RECALL | NFSCLDL_ZAPPED |
                            NFSCLDL_NEEDRECLAIM | NFSCLDL_DELEGRET)) == 0) {
                          clearok = 1;
                          LIST_FOREACH(owp, &dp->nfsdl_owner, nfsow_list) {
                              op = LIST_FIRST(&owp->nfsow_open);
                              if (op != NULL) {
                                  clearok = 0;
                                  break;
                              }
                          }
                          if (clearok) {
                              LIST_FOREACH(lp, &dp->nfsdl_lock, nfsl_list) {
                                  if (!LIST_EMPTY(&lp->nfsl_lock)) {
                                      clearok = 0;
                                      break;
                                  }
                              }
                          }
                          if (clearok) {
                              TAILQ_REMOVE(&clp->nfsc_deleg, dp, nfsdl_list);
                              LIST_REMOVE(dp, nfsdl_hash);
                              TAILQ_INSERT_HEAD(&dh, dp, nfsdl_list);
                              nfscl_delegcnt--;
                              nfsstatsv1.cldelegates--;
                          }
                      }
                      dp = ndp;
                  }
                  if (igotlock)
                          nfsv4_unlock(&clp->nfsc_lock, 0);
  
                  /*
                   * Do the recall on any layouts. To avoid trouble, always
                   * come back up here after having slept.
                   */
                  TAILQ_INIT(&rlh);
  tryagain2:
                  TAILQ_FOREACH_SAFE(lyp, &clp->nfsc_layout, nfsly_list, nlyp) {
                          if ((lyp->nfsly_flags & NFSLY_RECALL) != 0) {
                                  /*
                                   * Wait for outstanding I/O ops to be done.
                                   */
                                  if (lyp->nfsly_lock.nfslock_usecnt > 0 ||
                                      (lyp->nfsly_lock.nfslock_lock &
                                       NFSV4LOCK_LOCK) != 0) {
                                          lyp->nfsly_lock.nfslock_lock |=
                                              NFSV4LOCK_WANTED;
                                          msleep(&lyp->nfsly_lock.nfslock_lock,
                                              NFSCLSTATEMUTEXPTR, PVFS, "nfslyp",
                                              5 * hz);
                                          if (NFSCL_FORCEDISM(mp))
                                              goto terminate;
                                          goto tryagain2;
                                  }
                                  /* Move the layout to the recall list. */
                                  TAILQ_REMOVE(&clp->nfsc_layout, lyp,
                                      nfsly_list);
                                  LIST_REMOVE(lyp, nfsly_hash);
                                  TAILQ_INSERT_HEAD(&rlh, lyp, nfsly_list);
  
                                  /* Handle any layout commits. */
                                  if (!NFSHASNOLAYOUTCOMMIT(clp->nfsc_nmp) &&
                                      (lyp->nfsly_flags & NFSLY_WRITTEN) != 0) {
                                          lyp->nfsly_flags &= ~NFSLY_WRITTEN;
                                          NFSUNLOCKCLSTATE();
                                          NFSCL_DEBUG(3, "do layoutcommit\n");
                                          nfscl_dolayoutcommit(clp->nfsc_nmp, lyp,
                                              cred, p);
                                          NFSLOCKCLSTATE();
                                          goto tryagain2;
                                  }
                          }
                  }
  
                  /* Now, look for stale layouts. */
                  lyp = TAILQ_LAST(&clp->nfsc_layout, nfscllayouthead);
                  while (lyp != NULL) {
                          nlyp = TAILQ_PREV(lyp, nfscllayouthead, nfsly_list);
                          if (lyp->nfsly_timestamp < NFSD_MONOSEC &&
                              (lyp->nfsly_flags & (NFSLY_RECALL |
                               NFSLY_RETONCLOSE)) == 0 &&
                              lyp->nfsly_lock.nfslock_usecnt == 0 &&
                              lyp->nfsly_lock.nfslock_lock == 0) {
                                  NFSCL_DEBUG(4, "ret stale lay=%d\n",
                                      nfscl_layoutcnt);
                                  recallp = malloc(sizeof(*recallp),
                                      M_NFSLAYRECALL, M_NOWAIT);
                                  if (recallp == NULL)
                                          break;
                                  (void)nfscl_layoutrecall(NFSLAYOUTRETURN_FILE,
                                      lyp, NFSLAYOUTIOMODE_ANY, 0, UINT64_MAX,
                                      lyp->nfsly_stateid.seqid, 0, 0, NULL,
                                      recallp);
                          }
                          lyp = nlyp;
                  }
  
                  /*
                   * Free up any unreferenced device info structures.
                   */
                  LIST_FOREACH_SAFE(dip, &clp->nfsc_devinfo, nfsdi_list, ndip) {
                          if (dip->nfsdi_layoutrefs == 0 &&
                              dip->nfsdi_refcnt == 0) {
                                  NFSCL_DEBUG(4, "freeing devinfo\n");
                                  LIST_REMOVE(dip, nfsdi_list);
                                  nfscl_freedevinfo(dip);
                          }
                  }
                  NFSUNLOCKCLSTATE();
  
                  /* Do layout return(s), as required. */
                  TAILQ_FOREACH_SAFE(lyp, &rlh, nfsly_list, nlyp) {
                          TAILQ_REMOVE(&rlh, lyp, nfsly_list);
                          NFSCL_DEBUG(4, "ret layout\n");
                          nfscl_layoutreturn(clp->nfsc_nmp, lyp, cred, p);
                          if ((lyp->nfsly_flags & NFSLY_RETONCLOSE) != 0) {
                                  NFSLOCKCLSTATE();
                                  lyp->nfsly_flags |= NFSLY_RETURNED;
                                  wakeup(lyp);
                                  NFSUNLOCKCLSTATE();
                          } else
                                  nfscl_freelayout(lyp);
                  }
  
                  /*
                   * Delegreturn any delegations cleaned out or recalled.
                   */
                  TAILQ_FOREACH_SAFE(dp, &dh, nfsdl_list, ndp) {
                          newnfs_copycred(&dp->nfsdl_cred, cred);
                          (void) nfscl_trydelegreturn(dp, cred, clp->nfsc_nmp, p);
                          TAILQ_REMOVE(&dh, dp, nfsdl_list);
                          free(dp, M_NFSCLDELEG);
                  }
  
                  SLIST_INIT(&lfh);
                  /*
                   * Call nfscl_cleanupkext() once per second to check for
                   * open/lock owners where the process has exited.
                   */
                  mytime = NFSD_MONOSEC;
                  if (prevsec != mytime) {
                          prevsec = mytime;
                          nfscl_cleanupkext(clp, &lfh);
                  }
  
                  /*
                   * Do a ReleaseLockOwner for all lock owners where the
                   * associated process no longer exists, as found by
                   * nfscl_cleanupkext().
                   */
                  newnfs_setroot(cred);
                  SLIST_FOREACH_SAFE(lfhp, &lfh, nfslfh_list, nlfhp) {
                          LIST_FOREACH_SAFE(lp, &lfhp->nfslfh_lock, nfsl_list,
                              nlp) {
                                  (void)nfsrpc_rellockown(clp->nfsc_nmp, lp,
                                      lfhp->nfslfh_fh, lfhp->nfslfh_len, cred,
                                      p);
                                  nfscl_freelockowner(lp, 0);
                          }
                          free(lfhp, M_TEMP);
                  }
                  SLIST_INIT(&lfh);
  
                  NFSLOCKCLSTATE();
                  if ((clp->nfsc_flags & NFSCLFLAGS_RECOVER) == 0)
                          (void)mtx_sleep(clp, NFSCLSTATEMUTEXPTR, PWAIT, "nfscl",
                              hz);
  terminate:
                  if (clp->nfsc_flags & NFSCLFLAGS_UMOUNT) {
                          clp->nfsc_flags &= ~NFSCLFLAGS_HASTHREAD;
                          NFSUNLOCKCLSTATE();
                          NFSFREECRED(cred);
                          wakeup((caddr_t)clp);
                          return;
                  }
                  NFSUNLOCKCLSTATE();
          }
  }
  
  /*
   * Initiate state recovery. Called when NFSERR_STALECLIENTID,
   * NFSERR_STALESTATEID or NFSERR_BADSESSION is received.
   */
  void
  nfscl_initiate_recovery(struct nfsclclient *clp)
  {
  
          if (clp == NULL)
                  return;
          NFSLOCKCLSTATE();
          clp->nfsc_flags |= NFSCLFLAGS_RECOVER;
          NFSUNLOCKCLSTATE();
          wakeup((caddr_t)clp);
  }
  
  /*
   * Dump out the state stuff for debugging.
   */
  void
  nfscl_dumpstate(struct nfsmount *nmp, int openowner, int opens,
      int lockowner, int locks)
  {
          struct nfsclclient *clp;
          struct nfsclowner *owp;
          struct nfsclopen *op;
          struct nfscllockowner *lp;
          struct nfscllock *lop;
          struct nfscldeleg *dp;
  
          clp = nmp->nm_clp;
          if (clp == NULL) {
                  printf("nfscl dumpstate NULL clp\n");
                  return;
          }
          NFSLOCKCLSTATE();
          TAILQ_FOREACH(dp, &clp->nfsc_deleg, nfsdl_list) {
            LIST_FOREACH(owp, &dp->nfsdl_owner, nfsow_list) {
              if (openowner && !LIST_EMPTY(&owp->nfsow_open))
                  printf("owner=0x%x 0x%x 0x%x 0x%x seqid=%d\n",
                      owp->nfsow_owner[0], owp->nfsow_owner[1],
                      owp->nfsow_owner[2], owp->nfsow_owner[3],
                      owp->nfsow_seqid);
              LIST_FOREACH(op, &owp->nfsow_open, nfso_list) {
                  if (opens)
                      printf("open st=0x%x 0x%x 0x%x cnt=%d fh12=0x%x\n",
                          op->nfso_stateid.other[0], op->nfso_stateid.other[1],
                          op->nfso_stateid.other[2], op->nfso_opencnt,
                          op->nfso_fh[12]);
                  LIST_FOREACH(lp, &op->nfso_lock, nfsl_list) {
                      if (lockowner)
                          printf("lckown=0x%x 0x%x 0x%x 0x%x seqid=%d st=0x%x 0x%x 0x%x\n",
                              lp->nfsl_owner[0], lp->nfsl_owner[1],
                              lp->nfsl_owner[2], lp->nfsl_owner[3],
                              lp->nfsl_seqid,
                              lp->nfsl_stateid.other[0], lp->nfsl_stateid.other[1],
                              lp->nfsl_stateid.other[2]);
                      LIST_FOREACH(lop, &lp->nfsl_lock, nfslo_list) {
                          if (locks)
  #ifdef __FreeBSD__
                              printf("lck typ=%d fst=%ju end=%ju\n",
                                  lop->nfslo_type, (intmax_t)lop->nfslo_first,
                                  (intmax_t)lop->nfslo_end);
  #else
                              printf("lck typ=%d fst=%qd end=%qd\n",
                                  lop->nfslo_type, lop->nfslo_first,
                                  lop->nfslo_end);
  #endif
                      }
                  }
              }
            }
          }
          LIST_FOREACH(owp, &clp->nfsc_owner, nfsow_list) {
              if (openowner && !LIST_EMPTY(&owp->nfsow_open))
                  printf("owner=0x%x 0x%x 0x%x 0x%x seqid=%d\n",
                      owp->nfsow_owner[0], owp->nfsow_owner[1],
                      owp->nfsow_owner[2], owp->nfsow_owner[3],
                      owp->nfsow_seqid);
              LIST_FOREACH(op, &owp->nfsow_open, nfso_list) {
                  if (opens)
                      printf("open st=0x%x 0x%x 0x%x cnt=%d fh12=0x%x\n",
                          op->nfso_stateid.other[0], op->nfso_stateid.other[1],
                          op->nfso_stateid.other[2], op->nfso_opencnt,
                          op->nfso_fh[12]);
                  LIST_FOREACH(lp, &op->nfso_lock, nfsl_list) {
                      if (lockowner)
                          printf("lckown=0x%x 0x%x 0x%x 0x%x seqid=%d st=0x%x 0x%x 0x%x\n",
                              lp->nfsl_owner[0], lp->nfsl_owner[1],
                              lp->nfsl_owner[2], lp->nfsl_owner[3],
                              lp->nfsl_seqid,
                              lp->nfsl_stateid.other[0], lp->nfsl_stateid.other[1],
                              lp->nfsl_stateid.other[2]);
                      LIST_FOREACH(lop, &lp->nfsl_lock, nfslo_list) {
                          if (locks)
  #ifdef __FreeBSD__
                              printf("lck typ=%d fst=%ju end=%ju\n",
                                  lop->nfslo_type, (intmax_t)lop->nfslo_first,
                                  (intmax_t)lop->nfslo_end);
  #else
                              printf("lck typ=%d fst=%qd end=%qd\n",
                                  lop->nfslo_type, lop->nfslo_first,
                                  lop->nfslo_end);
  #endif
                      }
                  }
              }
          }
          NFSUNLOCKCLSTATE();
  }
  
  /*
   * Check for duplicate open owners and opens.
   * (Only used as a diagnostic aid.)
   */
  void
  nfscl_dupopen(vnode_t vp, int dupopens)
  {
          struct nfsclclient *clp;
          struct nfsclowner *owp, *owp2;
          struct nfsclopen *op, *op2;
          struct nfsfh *nfhp;
  
          clp = VFSTONFS(vp->v_mount)->nm_clp;
          if (clp == NULL) {
                  printf("nfscl dupopen NULL clp\n");
                  return;
          }
          nfhp = VTONFS(vp)->n_fhp;
          NFSLOCKCLSTATE();
  
          /*
           * First, search for duplicate owners.
           * These should never happen!
           */
          LIST_FOREACH(owp2, &clp->nfsc_owner, nfsow_list) {
              LIST_FOREACH(owp, &clp->nfsc_owner, nfsow_list) {
                  if (owp != owp2 &&
                      !NFSBCMP(owp->nfsow_owner, owp2->nfsow_owner,
                      NFSV4CL_LOCKNAMELEN)) {
                          NFSUNLOCKCLSTATE();
                          printf("DUP OWNER\n");
                          nfscl_dumpstate(VFSTONFS(vp->v_mount), 1, 1, 0, 0);
                          return;
                  }
              }
          }
  
          /*
           * Now, search for duplicate stateids.
           * These shouldn't happen, either.
           */
          LIST_FOREACH(owp2, &clp->nfsc_owner, nfsow_list) {
              LIST_FOREACH(op2, &owp2->nfsow_open, nfso_list) {
                  LIST_FOREACH(owp, &clp->nfsc_owner, nfsow_list) {
                      LIST_FOREACH(op, &owp->nfsow_open, nfso_list) {
                          if (op != op2 &&
                              (op->nfso_stateid.other[0] != 0 ||
                               op->nfso_stateid.other[1] != 0 ||
                               op->nfso_stateid.other[2] != 0) &&
                              op->nfso_stateid.other[0] == op2->nfso_stateid.other[0] &&
                              op->nfso_stateid.other[1] == op2->nfso_stateid.other[1] &&
                              op->nfso_stateid.other[2] == op2->nfso_stateid.other[2]) {
                              NFSUNLOCKCLSTATE();
                              printf("DUP STATEID\n");
                              nfscl_dumpstate(VFSTONFS(vp->v_mount), 1, 1, 0, 0);
                              return;
                          }
                      }
                  }
              }
          }
  
          /*
           * Now search for duplicate opens.
           * Duplicate opens for the same owner
           * should never occur. Other duplicates are
           * possible and are checked for if "dupopens"
           * is true.
           */
          LIST_FOREACH(owp2, &clp->nfsc_owner, nfsow_list) {
              LIST_FOREACH(op2, &owp2->nfsow_open, nfso_list) {
                  if (nfhp->nfh_len == op2->nfso_fhlen &&
                      !NFSBCMP(nfhp->nfh_fh, op2->nfso_fh, nfhp->nfh_len)) {
                      LIST_FOREACH(owp, &clp->nfsc_owner, nfsow_list) {
                          LIST_FOREACH(op, &owp->nfsow_open, nfso_list) {
                              if (op != op2 && nfhp->nfh_len == op->nfso_fhlen &&
                                  !NFSBCMP(nfhp->nfh_fh, op->nfso_fh, nfhp->nfh_len) &&
                                  (!NFSBCMP(op->nfso_own->nfsow_owner,
                                   op2->nfso_own->nfsow_owner, NFSV4CL_LOCKNAMELEN) ||
                                   dupopens)) {
                                  if (!NFSBCMP(op->nfso_own->nfsow_owner,
                                      op2->nfso_own->nfsow_owner, NFSV4CL_LOCKNAMELEN)) {
                                      NFSUNLOCKCLSTATE();
                                      printf("BADDUP OPEN\n");
                                  } else {
                                      NFSUNLOCKCLSTATE();
                                      printf("DUP OPEN\n");
                                  }
                                  nfscl_dumpstate(VFSTONFS(vp->v_mount), 1, 1, 0,
                                      0);
                                  return;
                              }
                          }
                      }
                  }
              }
          }
          NFSUNLOCKCLSTATE();
  }
  
  /*
   * During close, find an open that needs to be dereferenced and
   * dereference it. If there are no more opens for this file,
   * log a message to that effect.
   * Opens aren't actually Close'd until VOP_INACTIVE() is performed
   * on the file's vnode.
   * This is the safe way, since it is difficult to identify
   * which open the close is for and I/O can be performed after the
   * close(2) system call when a file is mmap'd.
   * If it returns 0 for success, there will be a referenced
   * clp returned via clpp.
   */
  int
  nfscl_getclose(vnode_t vp, struct nfsclclient **clpp)
  {
          struct nfsclclient *clp;
          struct nfsclowner *owp;
          struct nfsclopen *op;
          struct nfscldeleg *dp;
          struct nfsfh *nfhp;
          int error, notdecr;
  
          error = nfscl_getcl(vp->v_mount, NULL, NULL, false, true, &clp);
          if (error)
                  return (error);
          *clpp = clp;
  
          nfhp = VTONFS(vp)->n_fhp;
          notdecr = 1;
          NFSLOCKCLSTATE();
          /*
           * First, look for one under a delegation that was locally issued
           * and just decrement the opencnt for it. Since all my Opens against
           * the server are DENY_NONE, I don't see a problem with hanging
           * onto them. (It is much easier to use one of the extant Opens
           * that I already have on the server when a Delegation is recalled
           * than to do fresh Opens.) Someday, I might need to rethink this, but.
           */
          dp = nfscl_finddeleg(clp, nfhp->nfh_fh, nfhp->nfh_len);
          if (dp != NULL) {
                  LIST_FOREACH(owp, &dp->nfsdl_owner, nfsow_list) {
                          op = LIST_FIRST(&owp->nfsow_open);
                          if (op != NULL) {
                                  /*
                                   * Since a delegation is for a file, there
                                   * should never be more than one open for
                                   * each openowner.
                                   */
                                  if (LIST_NEXT(op, nfso_list) != NULL)
                                          panic("nfscdeleg opens");
                                  if (notdecr && op->nfso_opencnt > 0) {
                                          notdecr = 0;
                                          op->nfso_opencnt--;
                                          break;
                                  }
                          }
                  }
          }
  
          /* Now process the opens against the server. */
          LIST_FOREACH(op, NFSCLOPENHASH(clp, nfhp->nfh_fh, nfhp->nfh_len),
              nfso_hash) {
                  if (op->nfso_fhlen == nfhp->nfh_len &&
                      !NFSBCMP(op->nfso_fh, nfhp->nfh_fh,
                      nfhp->nfh_len)) {
                          /* Found an open, decrement cnt if possible */
                          if (notdecr && op->nfso_opencnt > 0) {
                                  notdecr = 0;
                                  op->nfso_opencnt--;
                          }
                          /*
                           * There are more opens, so just return.
                           */
                          if (op->nfso_opencnt > 0) {
                                  NFSUNLOCKCLSTATE();
                                  return (0);
                          }
                  }
          }
          NFSUNLOCKCLSTATE();
          if (notdecr)
                  printf("nfscl: never fnd open\n");
          return (0);
  }
  
  int
  nfscl_doclose(vnode_t vp, struct nfsclclient **clpp, NFSPROC_T *p)
  {
          struct nfsclclient *clp;
          struct nfsmount *nmp;
          struct nfsclowner *owp, *nowp;
          struct nfsclopen *op, *nop;
          struct nfsclopenhead delayed;
          struct nfscldeleg *dp;
          struct nfsfh *nfhp;
          struct nfsclrecalllayout *recallp;
          struct nfscllayout *lyp;
          int error;
  
          error = nfscl_getcl(vp->v_mount, NULL, NULL, false, true, &clp);
          if (error)
                  return (error);
          *clpp = clp;
  
          nmp = VFSTONFS(vp->v_mount);
          nfhp = VTONFS(vp)->n_fhp;
          recallp = malloc(sizeof(*recallp), M_NFSLAYRECALL, M_WAITOK);
          NFSLOCKCLSTATE();
          /*
           * First get rid of the local Open structures, which should be no
           * longer in use.
           */
          dp = nfscl_finddeleg(clp, nfhp->nfh_fh, nfhp->nfh_len);
          if (dp != NULL) {
                  LIST_FOREACH_SAFE(owp, &dp->nfsdl_owner, nfsow_list, nowp) {
                          op = LIST_FIRST(&owp->nfsow_open);
                          if (op != NULL) {
                                  KASSERT((op->nfso_opencnt == 0),
                                      ("nfscl: bad open cnt on deleg"));
                                  nfscl_freeopen(op, 1, true);
                          }
                          nfscl_freeopenowner(owp, 1);
                  }
          }
  
          /* Return any layouts marked return on close. */
          nfscl_retoncloselayout(vp, clp, nfhp->nfh_fh, nfhp->nfh_len, &recallp,
              &lyp);
  
          /* Now process the opens against the server. */
          LIST_INIT(&delayed);
  lookformore:
          LIST_FOREACH(op, NFSCLOPENHASH(clp, nfhp->nfh_fh, nfhp->nfh_len),
              nfso_hash) {
                  if (op->nfso_fhlen == nfhp->nfh_len &&
                      !NFSBCMP(op->nfso_fh, nfhp->nfh_fh,
                      nfhp->nfh_len)) {
                          /* Found an open, close it. */
  #ifdef DIAGNOSTIC
                          KASSERT((op->nfso_opencnt == 0),
                              ("nfscl: bad open cnt on server (%d)",
                               op->nfso_opencnt));
  #endif
                          NFSUNLOCKCLSTATE();
                          if (NFSHASNFSV4N(nmp))
                                  error = nfsrpc_doclose(nmp, op, p, false, true);
                          else
                                  error = nfsrpc_doclose(nmp, op, p, true, true);
                          NFSLOCKCLSTATE();
                          if (error == NFSERR_DELAY) {
                                  nfscl_unlinkopen(op);
                                  op->nfso_own = NULL;
                                  LIST_INSERT_HEAD(&delayed, op, nfso_list);
                          }
                          goto lookformore;
                  }
          }
          nfscl_clrelease(clp);
  
          /* Now, wait for any layout that is returned upon close. */
          if (lyp != NULL) {
                  while ((lyp->nfsly_flags & NFSLY_RETURNED) == 0) {
                          if (NFSCL_FORCEDISM(nmp->nm_mountp)) {
                                  lyp = NULL;
                                  break;
                          }
                          msleep(lyp, NFSCLSTATEMUTEXPTR, PZERO, "nfslroc", hz);
                  }
                  if (lyp != NULL)
                          nfscl_freelayout(lyp);
          }
  
          NFSUNLOCKCLSTATE();
          /*
           * recallp has been set NULL by nfscl_retoncloselayout() if it was
           * used by the function, but calling free() with a NULL pointer is ok.
           */
          free(recallp, M_NFSLAYRECALL);
  
          /* Now, loop retrying the delayed closes. */
          LIST_FOREACH_SAFE(op, &delayed, nfso_list, nop) {
                  nfsrpc_doclose(nmp, op, p, true, false);
                  LIST_REMOVE(op, nfso_list);
                  nfscl_freeopen(op, 0, false);
          }
          return (0);
  }
  
  /*
   * Return all delegations on this client.
   * (Must be called with client sleep lock.)
   */
  static void
  nfscl_delegreturnall(struct nfsclclient *clp, NFSPROC_T *p,
      struct nfscldeleghead *dhp)
  {
          struct nfscldeleg *dp, *ndp;
          struct ucred *cred;
  
          cred = newnfs_getcred();
          TAILQ_FOREACH_SAFE(dp, &clp->nfsc_deleg, nfsdl_list, ndp) {
                  nfscl_cleandeleg(dp);
                  (void) nfscl_trydelegreturn(dp, cred, clp->nfsc_nmp, p);
                  if (dhp != NULL) {
                          nfscl_freedeleg(&clp->nfsc_deleg, dp, false);
                          TAILQ_INSERT_HEAD(dhp, dp, nfsdl_list);
                  } else
                          nfscl_freedeleg(&clp->nfsc_deleg, dp, true);
          }
          NFSFREECRED(cred);
  }
  
  /*
   * Return any delegation for this vp.
   */
  void
  nfscl_delegreturnvp(vnode_t vp, NFSPROC_T *p)
  {
          struct nfsclclient *clp;
          struct nfscldeleg *dp;
          struct ucred *cred;
          struct nfsnode *np;
          struct nfsmount *nmp;
  
          nmp = VFSTONFS(vp->v_mount);
          NFSLOCKMNT(nmp);
          if ((nmp->nm_privflag & NFSMNTP_DELEGISSUED) == 0) {
                  NFSUNLOCKMNT(nmp);
                  return;
          }
          NFSUNLOCKMNT(nmp);
          np = VTONFS(vp);
          cred = newnfs_getcred();
          dp = NULL;
          NFSLOCKCLSTATE();
          clp = nmp->nm_clp;
          if (clp != NULL)
                  dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh,
                      np->n_fhp->nfh_len);
          if (dp != NULL) {
                  nfscl_cleandeleg(dp);
                  nfscl_freedeleg(&clp->nfsc_deleg, dp, false);
                  NFSUNLOCKCLSTATE();
                  newnfs_copycred(&dp->nfsdl_cred, cred);
                  nfscl_trydelegreturn(dp, cred, clp->nfsc_nmp, p);
                  free(dp, M_NFSCLDELEG);
          } else
                  NFSUNLOCKCLSTATE();
          NFSFREECRED(cred);
  }
  
  /*
   * Do a callback RPC.
   */
  void
  nfscl_docb(struct nfsrv_descript *nd, NFSPROC_T *p)
  {
          int clist, gotseq_ok, i, j, k, op, rcalls;
          u_int32_t *tl;
          struct nfsclclient *clp;
          struct nfscldeleg *dp = NULL;
          int numops, taglen = -1, error = 0, trunc __unused;
          u_int32_t minorvers = 0, retops = 0, *retopsp = NULL, *repp, cbident;
          u_char tag[NFSV4_SMALLSTR + 1], *tagstr;
          vnode_t vp = NULL;
          struct nfsnode *np;
          struct vattr va;
          struct nfsfh *nfhp;
          mount_t mp;
          nfsattrbit_t attrbits, rattrbits;
          nfsv4stateid_t stateid;
          uint32_t seqid, slotid = 0, highslot, cachethis __unused;
          uint8_t sessionid[NFSX_V4SESSIONID];
          struct mbuf *rep;
          struct nfscllayout *lyp;
          uint64_t filesid[2], len, off;
          int changed, gotone, laytype, recalltype;
          uint32_t iomode;
          struct nfsclrecalllayout *recallp = NULL;
          struct nfsclsession *tsep;
  
          gotseq_ok = 0;
          nfsrvd_rephead(nd);
          NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
          taglen = fxdr_unsigned(int, *tl);
          if (taglen < 0 || taglen > NFSV4_OPAQUELIMIT) {
                  error = EBADRPC;
                  taglen = -1;
                  goto nfsmout;
          }
          if (taglen <= NFSV4_SMALLSTR)
                  tagstr = tag;
          else
                  tagstr = malloc(taglen + 1, M_TEMP, M_WAITOK);
          error = nfsrv_mtostr(nd, tagstr, taglen);
          if (error) {
                  if (taglen > NFSV4_SMALLSTR)
                          free(tagstr, M_TEMP);
                  taglen = -1;
                  goto nfsmout;
          }
          (void) nfsm_strtom(nd, tag, taglen);
          if (taglen > NFSV4_SMALLSTR) {
                  free(tagstr, M_TEMP);
          }
          NFSM_BUILD(retopsp, u_int32_t *, NFSX_UNSIGNED);
          NFSM_DISSECT(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
          minorvers = fxdr_unsigned(u_int32_t, *tl++);
          if (minorvers != NFSV4_MINORVERSION &&
              minorvers != NFSV41_MINORVERSION &&
              minorvers != NFSV42_MINORVERSION)
                  nd->nd_repstat = NFSERR_MINORVERMISMATCH;
          cbident = fxdr_unsigned(u_int32_t, *tl++);
          if (nd->nd_repstat)
                  numops = 0;
          else
                  numops = fxdr_unsigned(int, *tl);
          /*
           * Loop around doing the sub ops.
           */
          for (i = 0; i < numops; i++) {
                  NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                  NFSM_BUILD(repp, u_int32_t *, 2 * NFSX_UNSIGNED);
                  *repp++ = *tl;
                  op = fxdr_unsigned(int, *tl);
                  nd->nd_procnum = op;
                  if (i == 0 && op != NFSV4OP_CBSEQUENCE && minorvers !=
                      NFSV4_MINORVERSION) {
                      nd->nd_repstat = NFSERR_OPNOTINSESS;
                      *repp = nfscl_errmap(nd, minorvers);
                      retops++;
                      break;
                  }
                  if (op < NFSV4OP_CBGETATTR ||
                     (op > NFSV4OP_CBRECALL && minorvers == NFSV4_MINORVERSION) ||
                     (op > NFSV4OP_CBNOTIFYDEVID &&
                      minorvers == NFSV41_MINORVERSION) ||
                     (op > NFSV4OP_CBOFFLOAD &&
                      minorvers == NFSV42_MINORVERSION)) {
                      nd->nd_repstat = NFSERR_OPILLEGAL;
                      *repp = nfscl_errmap(nd, minorvers);
                      retops++;
                      break;
                  }
                  if (op < NFSV42_CBNOPS)
                          nfsstatsv1.cbrpccnt[nd->nd_procnum]++;
                  switch (op) {
                  case NFSV4OP_CBGETATTR:
                          NFSCL_DEBUG(4, "cbgetattr\n");
                          mp = NULL;
                          vp = NULL;
                          error = nfsm_getfh(nd, &nfhp);
                          if (!error)
                                  error = nfsrv_getattrbits(nd, &attrbits,
                                      NULL, NULL);
                          if (!error) {
                                  mp = nfscl_getmnt(minorvers, sessionid, cbident,
                                      &clp);
                                  if (mp == NULL)
                                          error = NFSERR_SERVERFAULT;
                          }
                          if (!error) {
                                  error = nfscl_ngetreopen(mp, nfhp->nfh_fh,
                                      nfhp->nfh_len, p, &np);
                                  if (!error)
                                          vp = NFSTOV(np);
                          }
                          if (!error) {
                                  NFSZERO_ATTRBIT(&rattrbits);
                                  NFSLOCKCLSTATE();
                                  dp = nfscl_finddeleg(clp, nfhp->nfh_fh,
                                      nfhp->nfh_len);
                                  if (dp != NULL) {
                                          if (NFSISSET_ATTRBIT(&attrbits,
                                              NFSATTRBIT_SIZE)) {
                                                  if (vp != NULL)
                                                          va.va_size = np->n_size;
                                                  else
                                                          va.va_size =
                                                              dp->nfsdl_size;
                                                  NFSSETBIT_ATTRBIT(&rattrbits,
                                                      NFSATTRBIT_SIZE);
                                          }
                                          if (NFSISSET_ATTRBIT(&attrbits,
                                              NFSATTRBIT_CHANGE)) {
                                                  va.va_filerev =
                                                      dp->nfsdl_change;
                                                  if (vp == NULL ||
                                                      (np->n_flag & NDELEGMOD))
                                                          va.va_filerev++;
                                                  NFSSETBIT_ATTRBIT(&rattrbits,
                                                      NFSATTRBIT_CHANGE);
                                          }
                                  } else
                                          error = NFSERR_SERVERFAULT;
                                  NFSUNLOCKCLSTATE();
                          }
                          if (vp != NULL)
                                  vrele(vp);
                          if (mp != NULL)
                                  vfs_unbusy(mp);
                          if (nfhp != NULL)
                                  free(nfhp, M_NFSFH);
                          if (!error)
                                  (void) nfsv4_fillattr(nd, NULL, NULL, NULL, &va,
                                      NULL, 0, &rattrbits, NULL, p, 0, 0, 0, 0,
                                      (uint64_t)0, NULL);
                          break;
                  case NFSV4OP_CBRECALL:
                          NFSCL_DEBUG(4, "cbrecall\n");
                          NFSM_DISSECT(tl, u_int32_t *, NFSX_STATEID +
                              NFSX_UNSIGNED);
                          stateid.seqid = *tl++;
                          NFSBCOPY((caddr_t)tl, (caddr_t)stateid.other,
                              NFSX_STATEIDOTHER);
                          tl += (NFSX_STATEIDOTHER / NFSX_UNSIGNED);
                          trunc = fxdr_unsigned(int, *tl);
                          error = nfsm_getfh(nd, &nfhp);
                          if (!error) {
                                  NFSLOCKCLSTATE();
                                  if (minorvers == NFSV4_MINORVERSION)
                                          clp = nfscl_getclnt(cbident);
                                  else
                                          clp = nfscl_getclntsess(sessionid);
                                  if (clp != NULL) {
                                          dp = nfscl_finddeleg(clp, nfhp->nfh_fh,
                                              nfhp->nfh_len);
                                          if (dp != NULL && (dp->nfsdl_flags &
                                              NFSCLDL_DELEGRET) == 0) {
                                                  dp->nfsdl_flags |=
                                                      NFSCLDL_RECALL;
                                                  wakeup((caddr_t)clp);
                                          }
                                  } else {
                                          error = NFSERR_SERVERFAULT;
                                  }
                                  NFSUNLOCKCLSTATE();
                          }
                          if (nfhp != NULL)
                                  free(nfhp, M_NFSFH);
                          break;
                  case NFSV4OP_CBLAYOUTRECALL:
                          NFSCL_DEBUG(4, "cblayrec\n");
                          nfhp = NULL;
                          NFSM_DISSECT(tl, uint32_t *, 4 * NFSX_UNSIGNED);
                          laytype = fxdr_unsigned(int, *tl++);
                          iomode = fxdr_unsigned(uint32_t, *tl++);
                          if (newnfs_true == *tl++)
                                  changed = 1;
                          else
                                  changed = 0;
                          recalltype = fxdr_unsigned(int, *tl);
                          NFSCL_DEBUG(4, "layt=%d iom=%d ch=%d rectyp=%d\n",
                              laytype, iomode, changed, recalltype);
                          recallp = malloc(sizeof(*recallp), M_NFSLAYRECALL,
                              M_WAITOK);
                          if (laytype != NFSLAYOUT_NFSV4_1_FILES &&
                              laytype != NFSLAYOUT_FLEXFILE)
                                  error = NFSERR_NOMATCHLAYOUT;
                          else if (recalltype == NFSLAYOUTRETURN_FILE) {
                                  error = nfsm_getfh(nd, &nfhp);
                                  NFSCL_DEBUG(4, "retfile getfh=%d\n", error);
                                  if (error != 0)
                                          goto nfsmout;
                                  NFSM_DISSECT(tl, u_int32_t *, 2 * NFSX_HYPER +
                                      NFSX_STATEID);
                                  off = fxdr_hyper(tl); tl += 2;
                                  len = fxdr_hyper(tl); tl += 2;
                                  stateid.seqid = fxdr_unsigned(uint32_t, *tl++);
                                  NFSBCOPY(tl, stateid.other, NFSX_STATEIDOTHER);
                                  if (minorvers == NFSV4_MINORVERSION)
                                          error = NFSERR_NOTSUPP;
                                  NFSCL_DEBUG(4, "off=%ju len=%ju sq=%u err=%d\n",
                                      (uintmax_t)off, (uintmax_t)len,
                                      stateid.seqid, error);
                                  if (error == 0) {
                                          NFSLOCKCLSTATE();
                                          clp = nfscl_getclntsess(sessionid);
                                          NFSCL_DEBUG(4, "cbly clp=%p\n", clp);
                                          if (clp != NULL) {
                                                  lyp = nfscl_findlayout(clp,
                                                      nfhp->nfh_fh,
                                                      nfhp->nfh_len);
                                                  NFSCL_DEBUG(4, "cblyp=%p\n",
                                                      lyp);
                                                  if (lyp != NULL &&
                                                      (lyp->nfsly_flags &
                                                       (NFSLY_FILES |
                                                        NFSLY_FLEXFILE)) != 0 &&
                                                      !NFSBCMP(stateid.other,
                                                      lyp->nfsly_stateid.other,
                                                      NFSX_STATEIDOTHER)) {
                                                          error =
                                                              nfscl_layoutrecall(
                                                              recalltype,
                                                              lyp, iomode, off,
                                                              len, stateid.seqid,
                                                              0, 0, NULL,
                                                              recallp);
                                                          if (error == 0 &&
                                                              stateid.seqid >
                                                              lyp->nfsly_stateid.seqid)
                                                                  lyp->nfsly_stateid.seqid =
                                                                      stateid.seqid;
                                                          recallp = NULL;
                                                          wakeup(clp);
                                                          NFSCL_DEBUG(4,
                                                              "aft layrcal=%d "
                                                              "layseqid=%d\n",
                                                              error,
                                                              lyp->nfsly_stateid.seqid);
                                                  } else
                                                          error =
                                                            NFSERR_NOMATCHLAYOUT;
                                          } else
                                                  error = NFSERR_NOMATCHLAYOUT;
                                          NFSUNLOCKCLSTATE();
                                  }
                                  free(nfhp, M_NFSFH);
                          } else if (recalltype == NFSLAYOUTRETURN_FSID) {
                                  NFSM_DISSECT(tl, uint32_t *, 2 * NFSX_HYPER);
                                  filesid[0] = fxdr_hyper(tl); tl += 2;
                                  filesid[1] = fxdr_hyper(tl); tl += 2;
                                  gotone = 0;
                                  NFSLOCKCLSTATE();
                                  clp = nfscl_getclntsess(sessionid);
                                  if (clp != NULL) {
                                          TAILQ_FOREACH(lyp, &clp->nfsc_layout,
                                              nfsly_list) {
                                                  if (lyp->nfsly_filesid[0] ==
                                                      filesid[0] &&
                                                      lyp->nfsly_filesid[1] ==
                                                      filesid[1]) {
                                                          error =
                                                              nfscl_layoutrecall(
                                                              recalltype,
                                                              lyp, iomode, 0,
                                                              UINT64_MAX,
                                                              lyp->nfsly_stateid.seqid,
                                                              0, 0, NULL,
                                                              recallp);
                                                          recallp = NULL;
                                                          gotone = 1;
                                                  }
                                          }
                                          if (gotone != 0)
                                                  wakeup(clp);
                                          else
                                                  error = NFSERR_NOMATCHLAYOUT;
                                  } else
                                          error = NFSERR_NOMATCHLAYOUT;
                                  NFSUNLOCKCLSTATE();
                          } else if (recalltype == NFSLAYOUTRETURN_ALL) {
                                  gotone = 0;
                                  NFSLOCKCLSTATE();
                                  clp = nfscl_getclntsess(sessionid);
                                  if (clp != NULL) {
                                          TAILQ_FOREACH(lyp, &clp->nfsc_layout,
                                              nfsly_list) {
                                                  error = nfscl_layoutrecall(
                                                      recalltype, lyp, iomode, 0,
                                                      UINT64_MAX,
                                                      lyp->nfsly_stateid.seqid,
                                                      0, 0, NULL, recallp);
                                                  recallp = NULL;
                                                  gotone = 1;
                                          }
                                          if (gotone != 0)
                                                  wakeup(clp);
                                          else
                                                  error = NFSERR_NOMATCHLAYOUT;
                                  } else
                                          error = NFSERR_NOMATCHLAYOUT;
                                  NFSUNLOCKCLSTATE();
                          } else
                                  error = NFSERR_NOMATCHLAYOUT;
                          if (recallp != NULL) {
                                  free(recallp, M_NFSLAYRECALL);
                                  recallp = NULL;
                          }
                          break;
                  case NFSV4OP_CBSEQUENCE:
                          if (i != 0) {
                              error = NFSERR_SEQUENCEPOS;
                              break;
                          }
                          NFSM_DISSECT(tl, uint32_t *, NFSX_V4SESSIONID +
                              5 * NFSX_UNSIGNED);
                          bcopy(tl, sessionid, NFSX_V4SESSIONID);
                          tl += NFSX_V4SESSIONID / NFSX_UNSIGNED;
                          seqid = fxdr_unsigned(uint32_t, *tl++);
                          slotid = fxdr_unsigned(uint32_t, *tl++);
                          highslot = fxdr_unsigned(uint32_t, *tl++);
                          cachethis = *tl++;
                          /* Throw away the referring call stuff. */
                          clist = fxdr_unsigned(int, *tl);
                          for (j = 0; j < clist; j++) {
                                  NFSM_DISSECT(tl, uint32_t *, NFSX_V4SESSIONID +
                                      NFSX_UNSIGNED);
                                  tl += NFSX_V4SESSIONID / NFSX_UNSIGNED;
                                  rcalls = fxdr_unsigned(int, *tl);
                                  for (k = 0; k < rcalls; k++) {
                                          NFSM_DISSECT(tl, uint32_t *,
                                              2 * NFSX_UNSIGNED);
                                  }
                          }
                          NFSLOCKCLSTATE();
                          clp = nfscl_getclntsess(sessionid);
                          if (clp == NULL)
                                  error = NFSERR_SERVERFAULT;
                          if (error == 0) {
                                  tsep = nfsmnt_mdssession(clp->nfsc_nmp);
                                  error = nfsv4_seqsession(seqid, slotid,
                                      highslot, tsep->nfsess_cbslots, &rep,
                                      tsep->nfsess_backslots);
                          }
                          NFSUNLOCKCLSTATE();
                          if (error == 0 || error == NFSERR_REPLYFROMCACHE) {
                                  gotseq_ok = 1;
                                  if (rep != NULL) {
                                          /*
                                           * Handle a reply for a retried
                                           * callback.  The reply will be
                                           * re-inserted in the session cache
                                           * by the nfsv4_seqsess_cacherep() call
                                           * after out:
                                           */
                                          KASSERT(error == NFSERR_REPLYFROMCACHE,
                                              ("cbsequence: non-NULL rep"));
                                          NFSCL_DEBUG(4, "Got cbretry\n");
                                          m_freem(nd->nd_mreq);
                                          nd->nd_mreq = rep;
                                          rep = NULL;
                                          goto out;
                                  }
                                  NFSM_BUILD(tl, uint32_t *,
                                      NFSX_V4SESSIONID + 4 * NFSX_UNSIGNED);
                                  bcopy(sessionid, tl, NFSX_V4SESSIONID);
                                  tl += NFSX_V4SESSIONID / NFSX_UNSIGNED;
                                  *tl++ = txdr_unsigned(seqid);
                                  *tl++ = txdr_unsigned(slotid);
                                  *tl++ = txdr_unsigned(NFSV4_CBSLOTS - 1);
                                  *tl = txdr_unsigned(NFSV4_CBSLOTS - 1);
                          }
                          break;
                  default:
                          if (i == 0 && minorvers != NFSV4_MINORVERSION)
                                  error = NFSERR_OPNOTINSESS;
                          else {
                                  NFSCL_DEBUG(1, "unsupp callback %d\n", op);
                                  error = NFSERR_NOTSUPP;
                          }
                          break;
                  }
                  if (error) {
                          if (error == EBADRPC || error == NFSERR_BADXDR) {
                                  nd->nd_repstat = NFSERR_BADXDR;
                          } else {
                                  nd->nd_repstat = error;
                          }
                          error = 0;
                  }
                  retops++;
                  if (nd->nd_repstat) {
                          *repp = nfscl_errmap(nd, minorvers);
                          break;
                  } else
                          *repp = 0;      /* NFS4_OK */
          }
  nfsmout:
          if (recallp != NULL)
                  free(recallp, M_NFSLAYRECALL);
          if (error) {
                  if (error == EBADRPC || error == NFSERR_BADXDR)
                          nd->nd_repstat = NFSERR_BADXDR;
                  else
                          printf("nfsv4 comperr1=%d\n", error);
          }
          if (taglen == -1) {
                  NFSM_BUILD(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
                  *tl++ = 0;
                  *tl = 0;
          } else {
                  *retopsp = txdr_unsigned(retops);
          }
          *nd->nd_errp = nfscl_errmap(nd, minorvers);
  out:
          if (gotseq_ok != 0) {
                  rep = m_copym(nd->nd_mreq, 0, M_COPYALL, M_WAITOK);
                  NFSLOCKCLSTATE();
                  clp = nfscl_getclntsess(sessionid);
                  if (clp != NULL) {
                          tsep = nfsmnt_mdssession(clp->nfsc_nmp);
                          nfsv4_seqsess_cacherep(slotid, tsep->nfsess_cbslots,
                              NFSERR_OK, &rep);
                          NFSUNLOCKCLSTATE();
                  } else {
                          NFSUNLOCKCLSTATE();
                          m_freem(rep);
                  }
          }
  }
  
  /*
   * Generate the next cbident value. Basically just increment a static value
   * and then check that it isn't already in the list, if it has wrapped around.
   */
  static u_int32_t
  nfscl_nextcbident(void)
  {
          struct nfsclclient *clp;
          int matched;
          static u_int32_t nextcbident = 0;
          static int haswrapped = 0;
  
          nextcbident++;
          if (nextcbident == 0)
                  haswrapped = 1;
          if (haswrapped) {
                  /*
                   * Search the clientid list for one already using this cbident.
                   */
                  do {
                          matched = 0;
                          NFSLOCKCLSTATE();
                          LIST_FOREACH(clp, &nfsclhead, nfsc_list) {
                                  if (clp->nfsc_cbident == nextcbident) {
                                          matched = 1;
                                          break;
                                  }
                          }
                          NFSUNLOCKCLSTATE();
                          if (matched == 1)
                                  nextcbident++;
                  } while (matched);
          }
          return (nextcbident);
  }
  
  /*
   * Get the mount point related to a given cbident or session and busy it.
   */
  static mount_t
  nfscl_getmnt(int minorvers, uint8_t *sessionid, u_int32_t cbident,
      struct nfsclclient **clpp)
  {
          struct nfsclclient *clp;
          mount_t mp;
          int error;
          struct nfsclsession *tsep;
  
          *clpp = NULL;
          NFSLOCKCLSTATE();
          LIST_FOREACH(clp, &nfsclhead, nfsc_list) {
                  tsep = nfsmnt_mdssession(clp->nfsc_nmp);
                  if (minorvers == NFSV4_MINORVERSION) {
                          if (clp->nfsc_cbident == cbident)
                                  break;
                  } else if (!NFSBCMP(tsep->nfsess_sessionid, sessionid,
                      NFSX_V4SESSIONID))
                          break;
          }
          if (clp == NULL) {
                  NFSUNLOCKCLSTATE();
                  return (NULL);
          }
          mp = clp->nfsc_nmp->nm_mountp;
          vfs_ref(mp);
          NFSUNLOCKCLSTATE();
          error = vfs_busy(mp, 0);
          vfs_rel(mp);
          if (error != 0)
                  return (NULL);
          *clpp = clp;
          return (mp);
  }
  
  /*
   * Get the clientid pointer related to a given cbident.
   */
  static struct nfsclclient *
  nfscl_getclnt(u_int32_t cbident)
  {
          struct nfsclclient *clp;
  
          LIST_FOREACH(clp, &nfsclhead, nfsc_list)
                  if (clp->nfsc_cbident == cbident)
                          break;
          return (clp);
  }
  
  /*
   * Get the clientid pointer related to a given sessionid.
   */
  static struct nfsclclient *
  nfscl_getclntsess(uint8_t *sessionid)
  {
          struct nfsclclient *clp;
          struct nfsclsession *tsep;
  
          LIST_FOREACH(clp, &nfsclhead, nfsc_list) {
                  tsep = nfsmnt_mdssession(clp->nfsc_nmp);
                  if (!NFSBCMP(tsep->nfsess_sessionid, sessionid,
                      NFSX_V4SESSIONID))
                          break;
          }
          return (clp);
  }
  
  /*
   * Search for a lock conflict locally on the client. A conflict occurs if
   * - not same owner and overlapping byte range and at least one of them is
   *   a write lock or this is an unlock.
   */
  static int
  nfscl_localconflict(struct nfsclclient *clp, u_int8_t *fhp, int fhlen,
      struct nfscllock *nlop, u_int8_t *own, struct nfscldeleg *dp,
      struct nfscllock **lopp)
  {
          struct nfsclopen *op;
          int ret;
  
          if (dp != NULL) {
                  ret = nfscl_checkconflict(&dp->nfsdl_lock, nlop, own, lopp);
                  if (ret)
                          return (ret);
          }
          LIST_FOREACH(op, NFSCLOPENHASH(clp, fhp, fhlen), nfso_hash) {
                  if (op->nfso_fhlen == fhlen &&
                      !NFSBCMP(op->nfso_fh, fhp, fhlen)) {
                          ret = nfscl_checkconflict(&op->nfso_lock, nlop,
                              own, lopp);
                          if (ret)
                                  return (ret);
                  }
          }
          return (0);
  }
  
  static int
  nfscl_checkconflict(struct nfscllockownerhead *lhp, struct nfscllock *nlop,
      u_int8_t *own, struct nfscllock **lopp)
  {
          struct nfscllockowner *lp;
          struct nfscllock *lop;
  
          LIST_FOREACH(lp, lhp, nfsl_list) {
                  if (NFSBCMP(lp->nfsl_owner, own, NFSV4CL_LOCKNAMELEN)) {
                          LIST_FOREACH(lop, &lp->nfsl_lock, nfslo_list) {
                                  if (lop->nfslo_first >= nlop->nfslo_end)
                                          break;
                                  if (lop->nfslo_end <= nlop->nfslo_first)
                                          continue;
                                  if (lop->nfslo_type == F_WRLCK ||
                                      nlop->nfslo_type == F_WRLCK ||
                                      nlop->nfslo_type == F_UNLCK) {
                                          if (lopp != NULL)
                                                  *lopp = lop;
                                          return (NFSERR_DENIED);
                                  }
                          }
                  }
          }
          return (0);
  }
  
  /*
   * Check for a local conflicting lock.
   */
  int
  nfscl_lockt(vnode_t vp, struct nfsclclient *clp, u_int64_t off,
      u_int64_t len, struct flock *fl, NFSPROC_T *p, void *id, int flags)
  {
          struct nfscllock *lop, nlck;
          struct nfscldeleg *dp;
          struct nfsnode *np;
          u_int8_t own[NFSV4CL_LOCKNAMELEN];
          int error;
  
          nlck.nfslo_type = fl->l_type;
          nlck.nfslo_first = off;
          if (len == NFS64BITSSET) {
                  nlck.nfslo_end = NFS64BITSSET;
          } else {
                  nlck.nfslo_end = off + len;
                  if (nlck.nfslo_end <= nlck.nfslo_first)
                          return (NFSERR_INVAL);
          }
          np = VTONFS(vp);
          nfscl_filllockowner(id, own, flags);
          NFSLOCKCLSTATE();
          dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh, np->n_fhp->nfh_len);
          error = nfscl_localconflict(clp, np->n_fhp->nfh_fh, np->n_fhp->nfh_len,
              &nlck, own, dp, &lop);
          if (error != 0) {
                  fl->l_whence = SEEK_SET;
                  fl->l_start = lop->nfslo_first;
                  if (lop->nfslo_end == NFS64BITSSET)
                          fl->l_len = 0;
                  else
                          fl->l_len = lop->nfslo_end - lop->nfslo_first;
                  fl->l_pid = (pid_t)0;
                  fl->l_type = lop->nfslo_type;
                  error = -1;                     /* no RPC required */
          } else if (dp != NULL && ((dp->nfsdl_flags & NFSCLDL_WRITE) ||
              fl->l_type == F_RDLCK)) {
                  /*
                   * The delegation ensures that there isn't a conflicting
                   * lock on the server, so return -1 to indicate an RPC
                   * isn't required.
                   */
                  fl->l_type = F_UNLCK;
                  error = -1;
          }
          NFSUNLOCKCLSTATE();
          return (error);
  }
  
  /*
   * Handle Recall of a delegation.
   * The clp must be exclusive locked when this is called.
   */
  static int
  nfscl_recalldeleg(struct nfsclclient *clp, struct nfsmount *nmp,
      struct nfscldeleg *dp, vnode_t vp, struct ucred *cred, NFSPROC_T *p,
      int called_from_renewthread, vnode_t *vpp)
  {
          struct nfsclowner *owp, *lowp, *nowp;
          struct nfsclopen *op, *lop;
          struct nfscllockowner *lp;
          struct nfscllock *lckp;
          struct nfsnode *np;
          int error = 0, ret;
  
          if (vp == NULL) {
                  KASSERT(vpp != NULL, ("nfscl_recalldeleg: vpp NULL"));
                  *vpp = NULL;
                  /*
                   * First, get a vnode for the file. This is needed to do RPCs.
                   */
                  ret = nfscl_ngetreopen(nmp->nm_mountp, dp->nfsdl_fh,
                      dp->nfsdl_fhlen, p, &np);
                  if (ret) {
                          /*
                           * File isn't open, so nothing to move over to the
                           * server.
                           */
                          return (0);
                  }
                  vp = NFSTOV(np);
                  *vpp = vp;
          } else {
                  np = VTONFS(vp);
          }
          dp->nfsdl_flags &= ~NFSCLDL_MODTIMESET;
  
          /*
           * Ok, if it's a write delegation, flush data to the server, so
           * that close/open consistency is retained.
           */
          ret = 0;
          NFSLOCKNODE(np);
          if ((dp->nfsdl_flags & NFSCLDL_WRITE) && (np->n_flag & NMODIFIED)) {
                  np->n_flag |= NDELEGRECALL;
                  NFSUNLOCKNODE(np);
                  ret = ncl_flush(vp, MNT_WAIT, p, 1, called_from_renewthread);
                  NFSLOCKNODE(np);
                  np->n_flag &= ~NDELEGRECALL;
          }
          NFSINVALATTRCACHE(np);
          NFSUNLOCKNODE(np);
          if (ret == EIO && called_from_renewthread != 0) {
                  /*
                   * If the flush failed with EIO for the renew thread,
                   * return now, so that the dirty buffer will be flushed
                   * later.
                   */
                  return (ret);
          }
  
          /*
           * Now, for each openowner with opens issued locally, move them
           * over to state against the server.
           */
          LIST_FOREACH(lowp, &dp->nfsdl_owner, nfsow_list) {
                  lop = LIST_FIRST(&lowp->nfsow_open);
                  if (lop != NULL) {
                          if (LIST_NEXT(lop, nfso_list) != NULL)
                                  panic("nfsdlg mult opens");
                          /*
                           * Look for the same openowner against the server.
                           */
                          LIST_FOREACH(owp, &clp->nfsc_owner, nfsow_list) {
                                  if (!NFSBCMP(lowp->nfsow_owner,
                                      owp->nfsow_owner, NFSV4CL_LOCKNAMELEN)) {
                                          newnfs_copycred(&dp->nfsdl_cred, cred);
                                          ret = nfscl_moveopen(vp, clp, nmp, lop,
                                              owp, dp, cred, p);
                                          if (ret == NFSERR_STALECLIENTID ||
                                              ret == NFSERR_STALEDONTRECOVER ||
                                              ret == NFSERR_BADSESSION)
                                                  return (ret);
                                          if (ret) {
                                                  nfscl_freeopen(lop, 1, true);
                                                  if (!error)
                                                          error = ret;
                                          }
                                          break;
                                  }
                          }
  
                          /*
                           * If no openowner found, create one and get an open
                           * for it.
                           */
                          if (owp == NULL) {
                                  nowp = malloc(
                                      sizeof (struct nfsclowner), M_NFSCLOWNER,
                                      M_WAITOK);
                                  nfscl_newopen(clp, NULL, &owp, &nowp, &op, 
                                      NULL, lowp->nfsow_owner, dp->nfsdl_fh,
                                      dp->nfsdl_fhlen, NULL, NULL);
                                  newnfs_copycred(&dp->nfsdl_cred, cred);
                                  ret = nfscl_moveopen(vp, clp, nmp, lop,
                                      owp, dp, cred, p);
                                  if (ret) {
                                          nfscl_freeopenowner(owp, 0);
                                          if (ret == NFSERR_STALECLIENTID ||
                                              ret == NFSERR_STALEDONTRECOVER ||
                                              ret == NFSERR_BADSESSION)
                                                  return (ret);
                                          if (ret) {
                                                  nfscl_freeopen(lop, 1, true);
                                                  if (!error)
                                                          error = ret;
                                          }
                                  }
                          }
                  }
          }
  
          /*
           * Now, get byte range locks for any locks done locally.
           */
          LIST_FOREACH(lp, &dp->nfsdl_lock, nfsl_list) {
                  LIST_FOREACH(lckp, &lp->nfsl_lock, nfslo_list) {
                          newnfs_copycred(&dp->nfsdl_cred, cred);
                          ret = nfscl_relock(vp, clp, nmp, lp, lckp, cred, p);
                          if (ret == NFSERR_STALESTATEID ||
                              ret == NFSERR_STALEDONTRECOVER ||
                              ret == NFSERR_STALECLIENTID ||
                              ret == NFSERR_BADSESSION)
                                  return (ret);
                          if (ret && !error)
                                  error = ret;
                  }
          }
          return (error);
  }
  
  /*
   * Move a locally issued open over to an owner on the state list.
   * SIDE EFFECT: If it needs to sleep (do an rpc), it unlocks clstate and
   * returns with it unlocked.
   */
  static int
  nfscl_moveopen(vnode_t vp, struct nfsclclient *clp, struct nfsmount *nmp,
      struct nfsclopen *lop, struct nfsclowner *owp, struct nfscldeleg *dp,
      struct ucred *cred, NFSPROC_T *p)
  {
          struct nfsclopen *op, *nop;
          struct nfscldeleg *ndp;
          struct nfsnode *np;
          int error = 0, newone;
  
          /*
           * First, look for an appropriate open, If found, just increment the
           * opencnt in it.
           */
          LIST_FOREACH(op, &owp->nfsow_open, nfso_list) {
                  if ((op->nfso_mode & lop->nfso_mode) == lop->nfso_mode &&
                      op->nfso_fhlen == lop->nfso_fhlen &&
                      !NFSBCMP(op->nfso_fh, lop->nfso_fh, op->nfso_fhlen)) {
                          op->nfso_opencnt += lop->nfso_opencnt;
                          nfscl_freeopen(lop, 1, true);
                          return (0);
                  }
          }
  
          /* No appropriate open, so we have to do one against the server. */
          np = VTONFS(vp);
          nop = malloc(sizeof (struct nfsclopen) +
              lop->nfso_fhlen - 1, M_NFSCLOPEN, M_WAITOK);
          nop->nfso_hash.le_prev = NULL;
          newone = 0;
          nfscl_newopen(clp, NULL, &owp, NULL, &op, &nop, owp->nfsow_owner,
              lop->nfso_fh, lop->nfso_fhlen, cred, &newone);
          ndp = dp;
          error = nfscl_tryopen(nmp, vp, np->n_v4->n4_data, np->n_v4->n4_fhlen,
              lop->nfso_fh, lop->nfso_fhlen, lop->nfso_mode, op,
              NFS4NODENAME(np->n_v4), np->n_v4->n4_namelen, &ndp, 0, 0, cred, p);
          if (error) {
                  if (newone)
                          nfscl_freeopen(op, 0, true);
          } else {
                  op->nfso_mode |= lop->nfso_mode;
                  op->nfso_opencnt += lop->nfso_opencnt;
                  nfscl_freeopen(lop, 1, true);
          }
          if (nop != NULL)
                  free(nop, M_NFSCLOPEN);
          if (ndp != NULL) {
                  /*
                   * What should I do with the returned delegation, since the
                   * delegation is being recalled? For now, just printf and
                   * through it away.
                   */
                  printf("Moveopen returned deleg\n");
                  free(ndp, M_NFSCLDELEG);
          }
          return (error);
  }
  
  /*
   * Recall all delegations on this client.
   */
  static void
  nfscl_totalrecall(struct nfsclclient *clp)
  {
          struct nfscldeleg *dp;
  
          TAILQ_FOREACH(dp, &clp->nfsc_deleg, nfsdl_list) {
                  if ((dp->nfsdl_flags & NFSCLDL_DELEGRET) == 0)
                          dp->nfsdl_flags |= NFSCLDL_RECALL;
          }
  }
  
  /*
   * Relock byte ranges. Called for delegation recall and state expiry.
   */
  static int
  nfscl_relock(vnode_t vp, struct nfsclclient *clp, struct nfsmount *nmp,
      struct nfscllockowner *lp, struct nfscllock *lop, struct ucred *cred,
      NFSPROC_T *p)
  {
          struct nfscllockowner *nlp;
          struct nfsfh *nfhp;
          struct nfsnode *np;
          u_int64_t off, len;
          int error, newone, donelocally;
  
          if (NFSHASNFSV4N(nmp) && NFSHASONEOPENOWN(nmp)) {
                  np = VTONFS(vp);
                  NFSLOCKNODE(np);
                  np->n_flag |= NMIGHTBELOCKED;
                  NFSUNLOCKNODE(np);
          }
  
          off = lop->nfslo_first;
          len = lop->nfslo_end - lop->nfslo_first;
          error = nfscl_getbytelock(vp, off, len, lop->nfslo_type, cred, p,
              clp, 1, NULL, lp->nfsl_lockflags, lp->nfsl_owner,
              lp->nfsl_openowner, &nlp, &newone, &donelocally);
          if (error || donelocally)
                  return (error);
          nfhp = VTONFS(vp)->n_fhp;
          error = nfscl_trylock(nmp, vp, nfhp->nfh_fh,
              nfhp->nfh_len, nlp, newone, 0, off,
              len, lop->nfslo_type, cred, p);
          if (error)
                  nfscl_freelockowner(nlp, 0);
          return (error);
  }
  
  /*
   * Called to re-open a file. Basically get a vnode for the file handle
   * and then call nfsrpc_openrpc() to do the rest.
   */
  static int
  nfsrpc_reopen(struct nfsmount *nmp, u_int8_t *fhp, int fhlen,
      u_int32_t mode, struct nfsclopen *op, struct nfscldeleg **dpp,
      struct ucred *cred, NFSPROC_T *p)
  {
          struct nfsnode *np;
          vnode_t vp;
          int error;
  
          error = nfscl_ngetreopen(nmp->nm_mountp, fhp, fhlen, p, &np);
          if (error)
                  return (error);
          vp = NFSTOV(np);
          if (np->n_v4 != NULL) {
                  error = nfscl_tryopen(nmp, vp, np->n_v4->n4_data,
                      np->n_v4->n4_fhlen, fhp, fhlen, mode, op,
                      NFS4NODENAME(np->n_v4), np->n_v4->n4_namelen, dpp, 0, 0,
                      cred, p);
          } else {
                  error = EINVAL;
          }
          vrele(vp);
          return (error);
  }
  
  /*
   * Try an open against the server. Just call nfsrpc_openrpc(), retrying while
   * NFSERR_DELAY. Also, try system credentials, if the passed in credentials
   * fail.
   */
  static int
  nfscl_tryopen(struct nfsmount *nmp, vnode_t vp, u_int8_t *fhp, int fhlen,
      u_int8_t *newfhp, int newfhlen, u_int32_t mode, struct nfsclopen *op,
      u_int8_t *name, int namelen, struct nfscldeleg **ndpp,
      int reclaim, u_int32_t delegtype, struct ucred *cred, NFSPROC_T *p)
  {
          int error;
  
          do {
                  error = nfsrpc_openrpc(nmp, vp, fhp, fhlen, newfhp, newfhlen,
                      mode, op, name, namelen, ndpp, reclaim, delegtype, cred, p,
                      0, 0);
                  if (error == NFSERR_DELAY)
                          (void) nfs_catnap(PZERO, error, "nfstryop");
          } while (error == NFSERR_DELAY);
          if (error == EAUTH || error == EACCES) {
                  /* Try again using system credentials */
                  newnfs_setroot(cred);
                  do {
                      error = nfsrpc_openrpc(nmp, vp, fhp, fhlen, newfhp,
                          newfhlen, mode, op, name, namelen, ndpp, reclaim,
                          delegtype, cred, p, 1, 0);
                      if (error == NFSERR_DELAY)
                          (void) nfs_catnap(PZERO, error, "nfstryop");
                  } while (error == NFSERR_DELAY);
          }
          return (error);
  }
  
  /*
   * Try a byte range lock. Just loop on nfsrpc_lock() while it returns
   * NFSERR_DELAY. Also, retry with system credentials, if the provided
   * cred don't work.
   */
  static int
  nfscl_trylock(struct nfsmount *nmp, vnode_t vp, u_int8_t *fhp,
      int fhlen, struct nfscllockowner *nlp, int newone, int reclaim,
      u_int64_t off, u_int64_t len, short type, struct ucred *cred, NFSPROC_T *p)
  {
          struct nfsrv_descript nfsd, *nd = &nfsd;
          int error;
  
          do {
                  error = nfsrpc_lock(nd, nmp, vp, fhp, fhlen, nlp, newone,
                      reclaim, off, len, type, cred, p, 0);
                  if (!error && nd->nd_repstat == NFSERR_DELAY)
                          (void) nfs_catnap(PZERO, (int)nd->nd_repstat,
                              "nfstrylck");
          } while (!error && nd->nd_repstat == NFSERR_DELAY);
          if (!error)
                  error = nd->nd_repstat;
          if (error == EAUTH || error == EACCES) {
                  /* Try again using root credentials */
                  newnfs_setroot(cred);
                  do {
                          error = nfsrpc_lock(nd, nmp, vp, fhp, fhlen, nlp,
                              newone, reclaim, off, len, type, cred, p, 1);
                          if (!error && nd->nd_repstat == NFSERR_DELAY)
                                  (void) nfs_catnap(PZERO, (int)nd->nd_repstat,
                                      "nfstrylck");
                  } while (!error && nd->nd_repstat == NFSERR_DELAY);
                  if (!error)
                          error = nd->nd_repstat;
          }
          return (error);
  }
  
  /*
   * Try a delegreturn against the server. Just call nfsrpc_delegreturn(),
   * retrying while NFSERR_DELAY. Also, try system credentials, if the passed in
   * credentials fail.
   */
  static int
  nfscl_trydelegreturn(struct nfscldeleg *dp, struct ucred *cred,
      struct nfsmount *nmp, NFSPROC_T *p)
  {
          int error;
  
          do {
                  error = nfsrpc_delegreturn(dp, cred, nmp, p, 0);
                  if (error == NFSERR_DELAY)
                          (void) nfs_catnap(PZERO, error, "nfstrydp");
          } while (error == NFSERR_DELAY);
          if (error == EAUTH || error == EACCES) {
                  /* Try again using system credentials */
                  newnfs_setroot(cred);
                  do {
                          error = nfsrpc_delegreturn(dp, cred, nmp, p, 1);
                          if (error == NFSERR_DELAY)
                                  (void) nfs_catnap(PZERO, error, "nfstrydp");
                  } while (error == NFSERR_DELAY);
          }
          return (error);
  }
  
  /*
   * Try a close against the server. Just call nfsrpc_closerpc(),
   * retrying while NFSERR_DELAY. Also, try system credentials, if the passed in
   * credentials fail.
   */
  int
  nfscl_tryclose(struct nfsclopen *op, struct ucred *cred,
      struct nfsmount *nmp, NFSPROC_T *p, bool loop_on_delayed)
  {
          struct nfsrv_descript nfsd, *nd = &nfsd;
          int error;
  
          do {
                  error = nfsrpc_closerpc(nd, nmp, op, cred, p, 0);
                  if (loop_on_delayed && error == NFSERR_DELAY)
                          (void) nfs_catnap(PZERO, error, "nfstrycl");
          } while (loop_on_delayed && error == NFSERR_DELAY);
          if (error == EAUTH || error == EACCES) {
                  /* Try again using system credentials */
                  newnfs_setroot(cred);
                  do {
                          error = nfsrpc_closerpc(nd, nmp, op, cred, p, 1);
                          if (loop_on_delayed && error == NFSERR_DELAY)
                                  (void) nfs_catnap(PZERO, error, "nfstrycl");
                  } while (loop_on_delayed && error == NFSERR_DELAY);
          }
          return (error);
  }
  
  /*
   * Decide if a delegation on a file permits close without flushing writes
   * to the server. This might be a big performance win in some environments.
   * (Not useful until the client does caching on local stable storage.)
   */
  int
  nfscl_mustflush(vnode_t vp)
  {
          struct nfsclclient *clp;
          struct nfscldeleg *dp;
          struct nfsnode *np;
          struct nfsmount *nmp;
  
          np = VTONFS(vp);
          nmp = VFSTONFS(vp->v_mount);
          if (!NFSHASNFSV4(nmp))
                  return (1);
          NFSLOCKMNT(nmp);
          if ((nmp->nm_privflag & NFSMNTP_DELEGISSUED) == 0) {
                  NFSUNLOCKMNT(nmp);
                  return (1);
          }
          NFSUNLOCKMNT(nmp);
          NFSLOCKCLSTATE();
          clp = nfscl_findcl(nmp);
          if (clp == NULL) {
                  NFSUNLOCKCLSTATE();
                  return (1);
          }
          dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh, np->n_fhp->nfh_len);
          if (dp != NULL && (dp->nfsdl_flags &
              (NFSCLDL_WRITE | NFSCLDL_RECALL | NFSCLDL_DELEGRET)) ==
               NFSCLDL_WRITE &&
              (dp->nfsdl_sizelimit >= np->n_size ||
               !NFSHASSTRICT3530(nmp))) {
                  NFSUNLOCKCLSTATE();
                  return (0);
          }
          NFSUNLOCKCLSTATE();
          return (1);
  }
  
  /*
   * See if a (write) delegation exists for this file.
   */
  int
  nfscl_nodeleg(vnode_t vp, int writedeleg)
  {
          struct nfsclclient *clp;
          struct nfscldeleg *dp;
          struct nfsnode *np;
          struct nfsmount *nmp;
  
          np = VTONFS(vp);
          nmp = VFSTONFS(vp->v_mount);
          if (!NFSHASNFSV4(nmp))
                  return (1);
          NFSLOCKMNT(nmp);
          if ((nmp->nm_privflag & NFSMNTP_DELEGISSUED) == 0) {
                  NFSUNLOCKMNT(nmp);
                  return (1);
          }
          NFSUNLOCKMNT(nmp);
          NFSLOCKCLSTATE();
          clp = nfscl_findcl(nmp);
          if (clp == NULL) {
                  NFSUNLOCKCLSTATE();
                  return (1);
          }
          dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh, np->n_fhp->nfh_len);
          if (dp != NULL &&
              (dp->nfsdl_flags & (NFSCLDL_RECALL | NFSCLDL_DELEGRET)) == 0 &&
              (writedeleg == 0 || (dp->nfsdl_flags & NFSCLDL_WRITE) ==
               NFSCLDL_WRITE)) {
                  NFSUNLOCKCLSTATE();
                  return (0);
          }
          NFSUNLOCKCLSTATE();
          return (1);
  }
  
  /*
   * Look for an associated delegation that should be DelegReturned.
   */
  int
  nfscl_removedeleg(vnode_t vp, NFSPROC_T *p, nfsv4stateid_t *stp)
  {
          struct nfsclclient *clp;
          struct nfscldeleg *dp;
          struct nfsclowner *owp;
          struct nfscllockowner *lp;
          struct nfsmount *nmp;
          struct mount *mp;
          struct ucred *cred;
          struct nfsnode *np;
          int igotlock = 0, triedrecall = 0, needsrecall, retcnt = 0, islept;
  
          nmp = VFSTONFS(vp->v_mount);
          if (NFSHASPNFS(nmp))
                  return (retcnt);
          NFSLOCKMNT(nmp);
          if ((nmp->nm_privflag & NFSMNTP_DELEGISSUED) == 0) {
                  NFSUNLOCKMNT(nmp);
                  return (retcnt);
          }
          NFSUNLOCKMNT(nmp);
          np = VTONFS(vp);
          mp = nmp->nm_mountp;
          NFSLOCKCLSTATE();
          /*
           * Loop around waiting for:
           * - outstanding I/O operations on delegations to complete
           * - for a delegation on vp that has state, lock the client and
           *   do a recall
           * - return delegation with no state
           */
          while (1) {
                  clp = nfscl_findcl(nmp);
                  if (clp == NULL) {
                          NFSUNLOCKCLSTATE();
                          return (retcnt);
                  }
                  dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh,
                      np->n_fhp->nfh_len);
                  if (dp != NULL) {
                      /*
                       * Wait for outstanding I/O ops to be done.
                       */
                      if (dp->nfsdl_rwlock.nfslock_usecnt > 0) {
                          if (igotlock) {
                              nfsv4_unlock(&clp->nfsc_lock, 0);
                              igotlock = 0;
                          }
                          dp->nfsdl_rwlock.nfslock_lock |= NFSV4LOCK_WANTED;
                          msleep(&dp->nfsdl_rwlock, NFSCLSTATEMUTEXPTR, PZERO,
                              "nfscld", hz);
                          if (NFSCL_FORCEDISM(mp)) {
                              dp->nfsdl_flags &= ~NFSCLDL_DELEGRET;
                              NFSUNLOCKCLSTATE();
                              return (0);
                          }
                          continue;
                      }
                      needsrecall = 0;
                      LIST_FOREACH(owp, &dp->nfsdl_owner, nfsow_list) {
                          if (!LIST_EMPTY(&owp->nfsow_open)) {
                              needsrecall = 1;
                              break;
                          }
                      }
                      if (!needsrecall) {
                          LIST_FOREACH(lp, &dp->nfsdl_lock, nfsl_list) {
                              if (!LIST_EMPTY(&lp->nfsl_lock)) {
                                  needsrecall = 1;
                                  break;
                              }
                          }
                      }
                      if (needsrecall && !triedrecall) {
                          dp->nfsdl_flags |= NFSCLDL_DELEGRET;
                          islept = 0;
                          while (!igotlock) {
                              igotlock = nfsv4_lock(&clp->nfsc_lock, 1,
                                  &islept, NFSCLSTATEMUTEXPTR, mp);
                              if (NFSCL_FORCEDISM(mp)) {
                                  dp->nfsdl_flags &= ~NFSCLDL_DELEGRET;
                                  if (igotlock)
                                      nfsv4_unlock(&clp->nfsc_lock, 0);
                                  NFSUNLOCKCLSTATE();
                                  return (0);
                              }
                              if (islept)
                                  break;
                          }
                          if (islept)
                              continue;
                          NFSUNLOCKCLSTATE();
                          cred = newnfs_getcred();
                          newnfs_copycred(&dp->nfsdl_cred, cred);
                          nfscl_recalldeleg(clp, nmp, dp, vp, cred, p, 0, NULL);
                          NFSFREECRED(cred);
                          triedrecall = 1;
                          NFSLOCKCLSTATE();
                          nfsv4_unlock(&clp->nfsc_lock, 0);
                          igotlock = 0;
                          continue;
                      }
                      *stp = dp->nfsdl_stateid;
                      retcnt = 1;
                      nfscl_cleandeleg(dp);
                      nfscl_freedeleg(&clp->nfsc_deleg, dp, true);
                  }
                  if (igotlock)
                      nfsv4_unlock(&clp->nfsc_lock, 0);
                  NFSUNLOCKCLSTATE();
                  return (retcnt);
          }
  }
  
  /*
   * Look for associated delegation(s) that should be DelegReturned.
   */
  int
  nfscl_renamedeleg(vnode_t fvp, nfsv4stateid_t *fstp, int *gotfdp, vnode_t tvp,
      nfsv4stateid_t *tstp, int *gottdp, NFSPROC_T *p)
  {
          struct nfsclclient *clp;
          struct nfscldeleg *dp;
          struct nfsclowner *owp;
          struct nfscllockowner *lp;
          struct nfsmount *nmp;
          struct mount *mp;
          struct ucred *cred;
          struct nfsnode *np;
          int igotlock = 0, triedrecall = 0, needsrecall, retcnt = 0, islept;
  
          nmp = VFSTONFS(fvp->v_mount);
          *gotfdp = 0;
          *gottdp = 0;
          if (NFSHASPNFS(nmp))
                  return (retcnt);
          NFSLOCKMNT(nmp);
          if ((nmp->nm_privflag & NFSMNTP_DELEGISSUED) == 0) {
                  NFSUNLOCKMNT(nmp);
                  return (retcnt);
          }
          NFSUNLOCKMNT(nmp);
          mp = nmp->nm_mountp;
          NFSLOCKCLSTATE();
          /*
           * Loop around waiting for:
           * - outstanding I/O operations on delegations to complete
           * - for a delegation on fvp that has state, lock the client and
           *   do a recall
           * - return delegation(s) with no state.
           */
          while (1) {
                  clp = nfscl_findcl(nmp);
                  if (clp == NULL) {
                          NFSUNLOCKCLSTATE();
                          return (retcnt);
                  }
                  np = VTONFS(fvp);
                  dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh,
                      np->n_fhp->nfh_len);
                  if (dp != NULL && *gotfdp == 0) {
                      /*
                       * Wait for outstanding I/O ops to be done.
                       */
                      if (dp->nfsdl_rwlock.nfslock_usecnt > 0) {
                          if (igotlock) {
                              nfsv4_unlock(&clp->nfsc_lock, 0);
                              igotlock = 0;
                          }
                          dp->nfsdl_rwlock.nfslock_lock |= NFSV4LOCK_WANTED;
                          msleep(&dp->nfsdl_rwlock, NFSCLSTATEMUTEXPTR, PZERO,
                              "nfscld", hz);
                          if (NFSCL_FORCEDISM(mp)) {
                              dp->nfsdl_flags &= ~NFSCLDL_DELEGRET;
                              NFSUNLOCKCLSTATE();
                              *gotfdp = 0;
                              *gottdp = 0;
                              return (0);
                          }
                          continue;
                      }
                      needsrecall = 0;
                      LIST_FOREACH(owp, &dp->nfsdl_owner, nfsow_list) {
                          if (!LIST_EMPTY(&owp->nfsow_open)) {
                              needsrecall = 1;
                              break;
                          }
                      }
                      if (!needsrecall) {
                          LIST_FOREACH(lp, &dp->nfsdl_lock, nfsl_list) {
                              if (!LIST_EMPTY(&lp->nfsl_lock)) {
                                  needsrecall = 1;
                                  break;
                              }
                          }
                      }
                      if (needsrecall && !triedrecall) {
                          dp->nfsdl_flags |= NFSCLDL_DELEGRET;
                          islept = 0;
                          while (!igotlock) {
                              igotlock = nfsv4_lock(&clp->nfsc_lock, 1,
                                  &islept, NFSCLSTATEMUTEXPTR, mp);
                              if (NFSCL_FORCEDISM(mp)) {
                                  dp->nfsdl_flags &= ~NFSCLDL_DELEGRET;
                                  if (igotlock)
                                      nfsv4_unlock(&clp->nfsc_lock, 0);
                                  NFSUNLOCKCLSTATE();
                                  *gotfdp = 0;
                                  *gottdp = 0;
                                  return (0);
                              }
                              if (islept)
                                  break;
                          }
                          if (islept)
                              continue;
                          NFSUNLOCKCLSTATE();
                          cred = newnfs_getcred();
                          newnfs_copycred(&dp->nfsdl_cred, cred);
                          nfscl_recalldeleg(clp, nmp, dp, fvp, cred, p, 0, NULL);
                          NFSFREECRED(cred);
                          triedrecall = 1;
                          NFSLOCKCLSTATE();
                          nfsv4_unlock(&clp->nfsc_lock, 0);
                          igotlock = 0;
                          continue;
                      }
                      *fstp = dp->nfsdl_stateid;
                      retcnt++;
                      *gotfdp = 1;
                      nfscl_cleandeleg(dp);
                      nfscl_freedeleg(&clp->nfsc_deleg, dp, true);
                  }
                  if (igotlock) {
                      nfsv4_unlock(&clp->nfsc_lock, 0);
                      igotlock = 0;
                  }
                  if (tvp != NULL) {
                      np = VTONFS(tvp);
                      dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh,
                          np->n_fhp->nfh_len);
                      if (dp != NULL && *gottdp == 0) {
                          /*
                           * Wait for outstanding I/O ops to be done.
                           */
                          if (dp->nfsdl_rwlock.nfslock_usecnt > 0) {
                              dp->nfsdl_rwlock.nfslock_lock |= NFSV4LOCK_WANTED;
                              msleep(&dp->nfsdl_rwlock, NFSCLSTATEMUTEXPTR, PZERO,
                                  "nfscld", hz);
                              if (NFSCL_FORCEDISM(mp)) {
                                  NFSUNLOCKCLSTATE();
                                  *gotfdp = 0;
                                  *gottdp = 0;
                                  return (0);
                              }
                              continue;
                          }
                          LIST_FOREACH(owp, &dp->nfsdl_owner, nfsow_list) {
                              if (!LIST_EMPTY(&owp->nfsow_open)) {
                                  NFSUNLOCKCLSTATE();
                                  return (retcnt);
                              }
                          }
                          LIST_FOREACH(lp, &dp->nfsdl_lock, nfsl_list) {
                              if (!LIST_EMPTY(&lp->nfsl_lock)) {
                                  NFSUNLOCKCLSTATE();
                                  return (retcnt);
                              }
                          }
                          *tstp = dp->nfsdl_stateid;
                          retcnt++;
                          *gottdp = 1;
                          nfscl_cleandeleg(dp);
                          nfscl_freedeleg(&clp->nfsc_deleg, dp, true);
                      }
                  }
                  NFSUNLOCKCLSTATE();
                  return (retcnt);
          }
  }
  
  /*
   * Get a reference on the clientid associated with the mount point.
   * Return 1 if success, 0 otherwise.
   */
  int
  nfscl_getref(struct nfsmount *nmp)
  {
          struct nfsclclient *clp;
          int ret;
  
          NFSLOCKCLSTATE();
          clp = nfscl_findcl(nmp);
          if (clp == NULL) {
                  NFSUNLOCKCLSTATE();
                  return (0);
          }
          nfsv4_getref(&clp->nfsc_lock, NULL, NFSCLSTATEMUTEXPTR, nmp->nm_mountp);
          ret = 1;
          if (NFSCL_FORCEDISM(nmp->nm_mountp))
                  ret = 0;
          NFSUNLOCKCLSTATE();
          return (ret);
  }
  
  /*
   * Release a reference on a clientid acquired with the above call.
   */
  void
  nfscl_relref(struct nfsmount *nmp)
  {
          struct nfsclclient *clp;
  
          NFSLOCKCLSTATE();
          clp = nfscl_findcl(nmp);
          if (clp == NULL) {
                  NFSUNLOCKCLSTATE();
                  return;
          }
          nfsv4_relref(&clp->nfsc_lock);
          NFSUNLOCKCLSTATE();
  }
  
  /*
   * Save the size attribute in the delegation, since the nfsnode
   * is going away.
   */
  void
  nfscl_reclaimnode(vnode_t vp)
  {
          struct nfsclclient *clp;
          struct nfscldeleg *dp;
          struct nfsnode *np = VTONFS(vp);
          struct nfsmount *nmp;
  
          nmp = VFSTONFS(vp->v_mount);
          if (!NFSHASNFSV4(nmp))
                  return;
          NFSLOCKCLSTATE();
          clp = nfscl_findcl(nmp);
          if (clp == NULL) {
                  NFSUNLOCKCLSTATE();
                  return;
          }
          dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh, np->n_fhp->nfh_len);
          if (dp != NULL && (dp->nfsdl_flags & NFSCLDL_WRITE))
                  dp->nfsdl_size = np->n_size;
          NFSUNLOCKCLSTATE();
  }
  
  /*
   * Get the saved size attribute in the delegation, since it is a
   * newly allocated nfsnode.
   */
  void
  nfscl_newnode(vnode_t vp)
  {
          struct nfsclclient *clp;
          struct nfscldeleg *dp;
          struct nfsnode *np = VTONFS(vp);
          struct nfsmount *nmp;
  
          nmp = VFSTONFS(vp->v_mount);
          if (!NFSHASNFSV4(nmp))
                  return;
          NFSLOCKCLSTATE();
          clp = nfscl_findcl(nmp);
          if (clp == NULL) {
                  NFSUNLOCKCLSTATE();
                  return;
          }
          dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh, np->n_fhp->nfh_len);
          if (dp != NULL && (dp->nfsdl_flags & NFSCLDL_WRITE))
                  np->n_size = dp->nfsdl_size;
          NFSUNLOCKCLSTATE();
  }
  
  /*
   * If there is a valid write delegation for this file, set the modtime
   * to the local clock time.
   */
  void
  nfscl_delegmodtime(vnode_t vp)
  {
          struct nfsclclient *clp;
          struct nfscldeleg *dp;
          struct nfsnode *np = VTONFS(vp);
          struct nfsmount *nmp;
  
          nmp = VFSTONFS(vp->v_mount);
          if (!NFSHASNFSV4(nmp))
                  return;
          NFSLOCKMNT(nmp);
          if ((nmp->nm_privflag & NFSMNTP_DELEGISSUED) == 0) {
                  NFSUNLOCKMNT(nmp);
                  return;
          }
          NFSUNLOCKMNT(nmp);
          NFSLOCKCLSTATE();
          clp = nfscl_findcl(nmp);
          if (clp == NULL) {
                  NFSUNLOCKCLSTATE();
                  return;
          }
          dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh, np->n_fhp->nfh_len);
          if (dp != NULL && (dp->nfsdl_flags & NFSCLDL_WRITE)) {
                  nanotime(&dp->nfsdl_modtime);
                  dp->nfsdl_flags |= NFSCLDL_MODTIMESET;
          }
          NFSUNLOCKCLSTATE();
  }
  
  /*
   * If there is a valid write delegation for this file with a modtime set,
   * put that modtime in mtime.
   */
  void
  nfscl_deleggetmodtime(vnode_t vp, struct timespec *mtime)
  {
          struct nfsclclient *clp;
          struct nfscldeleg *dp;
          struct nfsnode *np = VTONFS(vp);
          struct nfsmount *nmp;
  
          nmp = VFSTONFS(vp->v_mount);
          if (!NFSHASNFSV4(nmp))
                  return;
          NFSLOCKMNT(nmp);
          if ((nmp->nm_privflag & NFSMNTP_DELEGISSUED) == 0) {
                  NFSUNLOCKMNT(nmp);
                  return;
          }
          NFSUNLOCKMNT(nmp);
          NFSLOCKCLSTATE();
          clp = nfscl_findcl(nmp);
          if (clp == NULL) {
                  NFSUNLOCKCLSTATE();
                  return;
          }
          dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh, np->n_fhp->nfh_len);
          if (dp != NULL &&
              (dp->nfsdl_flags & (NFSCLDL_WRITE | NFSCLDL_MODTIMESET)) ==
              (NFSCLDL_WRITE | NFSCLDL_MODTIMESET))
                  *mtime = dp->nfsdl_modtime;
          NFSUNLOCKCLSTATE();
  }
  
  static int
  nfscl_errmap(struct nfsrv_descript *nd, u_int32_t minorvers)
  {
          short *defaulterrp, *errp;
  
          if (!nd->nd_repstat)
                  return (0);
          if (nd->nd_procnum == NFSPROC_NOOP)
                  return (txdr_unsigned(nd->nd_repstat & 0xffff));
          if (nd->nd_repstat == EBADRPC)
                  return (txdr_unsigned(NFSERR_BADXDR));
          if (nd->nd_repstat == NFSERR_MINORVERMISMATCH ||
              nd->nd_repstat == NFSERR_OPILLEGAL)
                  return (txdr_unsigned(nd->nd_repstat));
          if (nd->nd_repstat >= NFSERR_BADIOMODE && nd->nd_repstat < 20000 &&
              minorvers > NFSV4_MINORVERSION) {
                  /* NFSv4.n error. */
                  return (txdr_unsigned(nd->nd_repstat));
          }
          if (nd->nd_procnum < NFSV4OP_CBNOPS)
                  errp = defaulterrp = nfscl_cberrmap[nd->nd_procnum];
          else
                  return (txdr_unsigned(nd->nd_repstat));
          while (*++errp)
                  if (*errp == (short)nd->nd_repstat)
                          return (txdr_unsigned(nd->nd_repstat));
          return (txdr_unsigned(*defaulterrp));
  }
  
  /*
   * Called to find/add a layout to a client.
   * This function returns the layout with a refcnt (shared lock) upon
   * success (returns 0) or with no lock/refcnt on the layout when an
   * error is returned.
   * If a layout is passed in via lypp, it is locked (exclusively locked).
   */
  int
  nfscl_layout(struct nfsmount *nmp, vnode_t vp, u_int8_t *fhp, int fhlen,
      nfsv4stateid_t *stateidp, int layouttype, int retonclose,
      struct nfsclflayouthead *fhlp, struct nfscllayout **lypp,
      struct ucred *cred, NFSPROC_T *p)
  {
          struct nfsclclient *clp;
          struct nfscllayout *lyp, *tlyp;
          struct nfsclflayout *flp;
          struct nfsnode *np = VTONFS(vp);
          mount_t mp;
          int layout_passed_in;
  
          mp = nmp->nm_mountp;
          layout_passed_in = 1;
          tlyp = NULL;
          lyp = *lypp;
          if (lyp == NULL) {
                  layout_passed_in = 0;
                  tlyp = malloc(sizeof(*tlyp) + fhlen - 1, M_NFSLAYOUT,
                      M_WAITOK | M_ZERO);
          }
  
          NFSLOCKCLSTATE();
          clp = nmp->nm_clp;
          if (clp == NULL) {
                  if (layout_passed_in != 0)
                          nfsv4_unlock(&lyp->nfsly_lock, 0);
                  NFSUNLOCKCLSTATE();
                  if (tlyp != NULL)
                          free(tlyp, M_NFSLAYOUT);
                  return (EPERM);
          }
          if (lyp == NULL) {
                  /*
                   * Although no lyp was passed in, another thread might have
                   * allocated one. If one is found, just increment it's ref
                   * count and return it.
                   */
                  lyp = nfscl_findlayout(clp, fhp, fhlen);
                  if (lyp == NULL) {
                          lyp = tlyp;
                          tlyp = NULL;
                          lyp->nfsly_stateid.seqid = stateidp->seqid;
                          lyp->nfsly_stateid.other[0] = stateidp->other[0];
                          lyp->nfsly_stateid.other[1] = stateidp->other[1];
                          lyp->nfsly_stateid.other[2] = stateidp->other[2];
                          lyp->nfsly_lastbyte = 0;
                          LIST_INIT(&lyp->nfsly_flayread);
                          LIST_INIT(&lyp->nfsly_flayrw);
                          LIST_INIT(&lyp->nfsly_recall);
                          lyp->nfsly_filesid[0] = np->n_vattr.na_filesid[0];
                          lyp->nfsly_filesid[1] = np->n_vattr.na_filesid[1];
                          lyp->nfsly_clp = clp;
                          if (layouttype == NFSLAYOUT_FLEXFILE)
                                  lyp->nfsly_flags = NFSLY_FLEXFILE;
                          else
                                  lyp->nfsly_flags = NFSLY_FILES;
                          if (retonclose != 0)
                                  lyp->nfsly_flags |= NFSLY_RETONCLOSE;
                          lyp->nfsly_fhlen = fhlen;
                          NFSBCOPY(fhp, lyp->nfsly_fh, fhlen);
                          TAILQ_INSERT_HEAD(&clp->nfsc_layout, lyp, nfsly_list);
                          LIST_INSERT_HEAD(NFSCLLAYOUTHASH(clp, fhp, fhlen), lyp,
                              nfsly_hash);
                          lyp->nfsly_timestamp = NFSD_MONOSEC + 120;
                          nfscl_layoutcnt++;
                          nfsstatsv1.cllayouts++;
                  } else {
                          if (retonclose != 0)
                                  lyp->nfsly_flags |= NFSLY_RETONCLOSE;
                          if (stateidp->seqid > lyp->nfsly_stateid.seqid)
                                  lyp->nfsly_stateid.seqid = stateidp->seqid;
                          TAILQ_REMOVE(&clp->nfsc_layout, lyp, nfsly_list);
                          TAILQ_INSERT_HEAD(&clp->nfsc_layout, lyp, nfsly_list);
                          lyp->nfsly_timestamp = NFSD_MONOSEC + 120;
                  }
                  nfsv4_getref(&lyp->nfsly_lock, NULL, NFSCLSTATEMUTEXPTR, mp);
                  if (NFSCL_FORCEDISM(mp)) {
                          NFSUNLOCKCLSTATE();
                          if (tlyp != NULL)
                                  free(tlyp, M_NFSLAYOUT);
                          return (EPERM);
                  }
                  *lypp = lyp;
          } else if (stateidp->seqid > lyp->nfsly_stateid.seqid)
                  lyp->nfsly_stateid.seqid = stateidp->seqid;
  
          /* Merge the new list of File Layouts into the list. */
          flp = LIST_FIRST(fhlp);
          if (flp != NULL) {
                  if (flp->nfsfl_iomode == NFSLAYOUTIOMODE_READ)
                          nfscl_mergeflayouts(&lyp->nfsly_flayread, fhlp);
                  else
                          nfscl_mergeflayouts(&lyp->nfsly_flayrw, fhlp);
          }
          if (layout_passed_in != 0)
                  nfsv4_unlock(&lyp->nfsly_lock, 1);
          NFSUNLOCKCLSTATE();
          if (tlyp != NULL)
                  free(tlyp, M_NFSLAYOUT);
          return (0);
  }
  
  /*
   * Search for a layout by MDS file handle.
   * If one is found, it is returned with a refcnt (shared lock) iff
   * retflpp returned non-NULL and locked (exclusive locked) iff retflpp is
   * returned NULL.
   */
  struct nfscllayout *
  nfscl_getlayout(struct nfsclclient *clp, uint8_t *fhp, int fhlen,
      uint64_t off, uint32_t rwaccess, struct nfsclflayout **retflpp,
      int *recalledp)
  {
          struct nfscllayout *lyp;
          mount_t mp;
          int error, igotlock;
  
          mp = clp->nfsc_nmp->nm_mountp;
          *recalledp = 0;
          *retflpp = NULL;
          NFSLOCKCLSTATE();
          lyp = nfscl_findlayout(clp, fhp, fhlen);
          if (lyp != NULL) {
                  if ((lyp->nfsly_flags & NFSLY_RECALL) == 0) {
                          TAILQ_REMOVE(&clp->nfsc_layout, lyp, nfsly_list);
                          TAILQ_INSERT_HEAD(&clp->nfsc_layout, lyp, nfsly_list);
                          lyp->nfsly_timestamp = NFSD_MONOSEC + 120;
                          error = nfscl_findlayoutforio(lyp, off, rwaccess,
                              retflpp);
                          if (error == 0)
                                  nfsv4_getref(&lyp->nfsly_lock, NULL,
                                      NFSCLSTATEMUTEXPTR, mp);
                          else {
                                  do {
                                          igotlock = nfsv4_lock(&lyp->nfsly_lock,
                                              1, NULL, NFSCLSTATEMUTEXPTR, mp);
                                  } while (igotlock == 0 && !NFSCL_FORCEDISM(mp));
                                  *retflpp = NULL;
                          }
                          if (NFSCL_FORCEDISM(mp)) {
                                  lyp = NULL;
                                  *recalledp = 1;
                          }
                  } else {
                          lyp = NULL;
                          *recalledp = 1;
                  }
          }
          NFSUNLOCKCLSTATE();
          return (lyp);
  }
  
  /*
   * Search for a layout by MDS file handle. If one is found, mark in to be
   * recalled, if it already marked "return on close".
   */
  static void
  nfscl_retoncloselayout(vnode_t vp, struct nfsclclient *clp, uint8_t *fhp,
      int fhlen, struct nfsclrecalllayout **recallpp, struct nfscllayout **lypp)
  {
          struct nfscllayout *lyp;
          uint32_t iomode;
  
          *lypp = NULL;
          if (vp->v_type != VREG || !NFSHASPNFS(VFSTONFS(vp->v_mount)) ||
              nfscl_enablecallb == 0 || nfs_numnfscbd == 0 ||
              (VTONFS(vp)->n_flag & NNOLAYOUT) != 0)
                  return;
          lyp = nfscl_findlayout(clp, fhp, fhlen);
          if (lyp != NULL && (lyp->nfsly_flags & NFSLY_RETONCLOSE) != 0) {
                  if ((lyp->nfsly_flags & NFSLY_RECALL) == 0) {
                          iomode = 0;
                          if (!LIST_EMPTY(&lyp->nfsly_flayread))
                                  iomode |= NFSLAYOUTIOMODE_READ;
                          if (!LIST_EMPTY(&lyp->nfsly_flayrw))
                                  iomode |= NFSLAYOUTIOMODE_RW;
                          nfscl_layoutrecall(NFSLAYOUTRETURN_FILE, lyp, iomode,
                              0, UINT64_MAX, lyp->nfsly_stateid.seqid, 0, 0, NULL,
                              *recallpp);
                          NFSCL_DEBUG(4, "retoncls recall iomode=%d\n", iomode);
                          *recallpp = NULL;
                  }
  
                  /* Now, wake up renew thread to do LayoutReturn. */
                  wakeup(clp);
                  *lypp = lyp;
          }
  }
  
  /*
   * Mark the layout to be recalled and with an error.
   * Also, disable the dsp from further use.
   */
  void
  nfscl_dserr(uint32_t op, uint32_t stat, struct nfscldevinfo *dp,
      struct nfscllayout *lyp, struct nfsclds *dsp)
  {
          struct nfsclrecalllayout *recallp;
          uint32_t iomode;
  
          printf("DS being disabled, error=%d\n", stat);
          /* Set up the return of the layout. */
          recallp = malloc(sizeof(*recallp), M_NFSLAYRECALL, M_WAITOK);
          iomode = 0;
          NFSLOCKCLSTATE();
          if ((lyp->nfsly_flags & NFSLY_RECALL) == 0) {
                  if (!LIST_EMPTY(&lyp->nfsly_flayread))
                          iomode |= NFSLAYOUTIOMODE_READ;
                  if (!LIST_EMPTY(&lyp->nfsly_flayrw))
                          iomode |= NFSLAYOUTIOMODE_RW;
                  (void)nfscl_layoutrecall(NFSLAYOUTRETURN_FILE, lyp, iomode,
                      0, UINT64_MAX, lyp->nfsly_stateid.seqid, stat, op,
                      dp->nfsdi_deviceid, recallp);
                  NFSUNLOCKCLSTATE();
                  NFSCL_DEBUG(4, "nfscl_dserr recall iomode=%d\n", iomode);
          } else {
                  NFSUNLOCKCLSTATE();
                  free(recallp, M_NFSLAYRECALL);
          }
  
          /* And shut the TCP connection down. */
          nfscl_cancelreqs(dsp);
  }
  
  /*
   * Cancel all RPCs for this "dsp" by closing the connection.
   * Also, mark the session as defunct.
   * If NFSCLDS_SAMECONN is set, the connection is shared with other DSs and
   * cannot be shut down.
   */
  void
  nfscl_cancelreqs(struct nfsclds *dsp)
  {
          struct __rpc_client *cl;
          static int non_event;
  
          NFSLOCKDS(dsp);
          if ((dsp->nfsclds_flags & (NFSCLDS_CLOSED | NFSCLDS_SAMECONN)) == 0 &&
              dsp->nfsclds_sockp != NULL &&
              dsp->nfsclds_sockp->nr_client != NULL) {
                  dsp->nfsclds_flags |= NFSCLDS_CLOSED;
                  cl = dsp->nfsclds_sockp->nr_client;
                  dsp->nfsclds_sess.nfsess_defunct = 1;
                  NFSUNLOCKDS(dsp);
                  CLNT_CLOSE(cl);
                  /*
                   * This 1sec sleep is done to reduce the number of reconnect
                   * attempts made on the DS while it has failed.
                   */
                  tsleep(&non_event, PVFS, "ndscls", hz);
                  return;
          }
          NFSUNLOCKDS(dsp);
  }
  
  /*
   * Dereference a layout.
   */
  void
  nfscl_rellayout(struct nfscllayout *lyp, int exclocked)
  {
  
          NFSLOCKCLSTATE();
          if (exclocked != 0)
                  nfsv4_unlock(&lyp->nfsly_lock, 0);
          else
                  nfsv4_relref(&lyp->nfsly_lock);
          NFSUNLOCKCLSTATE();
  }
  
  /*
   * Search for a devinfo by deviceid. If one is found, return it after
   * acquiring a reference count on it.
   */
  struct nfscldevinfo *
  nfscl_getdevinfo(struct nfsclclient *clp, uint8_t *deviceid,
      struct nfscldevinfo *dip)
  {
  
          NFSLOCKCLSTATE();
          if (dip == NULL)
                  dip = nfscl_finddevinfo(clp, deviceid);
          if (dip != NULL)
                  dip->nfsdi_refcnt++;
          NFSUNLOCKCLSTATE();
          return (dip);
  }
  
  /*
   * Dereference a devinfo structure.
   */
  static void
  nfscl_reldevinfo_locked(struct nfscldevinfo *dip)
  {
  
          dip->nfsdi_refcnt--;
          if (dip->nfsdi_refcnt == 0)
                  wakeup(&dip->nfsdi_refcnt);
  }
  
  /*
   * Dereference a devinfo structure.
   */
  void
  nfscl_reldevinfo(struct nfscldevinfo *dip)
  {
  
          NFSLOCKCLSTATE();
          nfscl_reldevinfo_locked(dip);
          NFSUNLOCKCLSTATE();
  }
  
  /*
   * Find a layout for this file handle. Return NULL upon failure.
   */
  static struct nfscllayout *
  nfscl_findlayout(struct nfsclclient *clp, u_int8_t *fhp, int fhlen)
  {
          struct nfscllayout *lyp;
  
          LIST_FOREACH(lyp, NFSCLLAYOUTHASH(clp, fhp, fhlen), nfsly_hash)
                  if (lyp->nfsly_fhlen == fhlen &&
                      !NFSBCMP(lyp->nfsly_fh, fhp, fhlen))
                          break;
          return (lyp);
  }
  
  /*
   * Find a devinfo for this deviceid. Return NULL upon failure.
   */
  static struct nfscldevinfo *
  nfscl_finddevinfo(struct nfsclclient *clp, uint8_t *deviceid)
  {
          struct nfscldevinfo *dip;
  
          LIST_FOREACH(dip, &clp->nfsc_devinfo, nfsdi_list)
                  if (NFSBCMP(dip->nfsdi_deviceid, deviceid, NFSX_V4DEVICEID)
                      == 0)
                          break;
          return (dip);
  }
  
  /*
   * Merge the new file layout list into the main one, maintaining it in
   * increasing offset order.
   */
  static void
  nfscl_mergeflayouts(struct nfsclflayouthead *fhlp,
      struct nfsclflayouthead *newfhlp)
  {
          struct nfsclflayout *flp, *nflp, *prevflp, *tflp;
  
          flp = LIST_FIRST(fhlp);
          prevflp = NULL;
          LIST_FOREACH_SAFE(nflp, newfhlp, nfsfl_list, tflp) {
                  while (flp != NULL && flp->nfsfl_off < nflp->nfsfl_off) {
                          prevflp = flp;
                          flp = LIST_NEXT(flp, nfsfl_list);
                  }
                  if (prevflp == NULL)
                          LIST_INSERT_HEAD(fhlp, nflp, nfsfl_list);
                  else
                          LIST_INSERT_AFTER(prevflp, nflp, nfsfl_list);
                  prevflp = nflp;
          }
  }
  
  /*
   * Add this nfscldevinfo to the client, if it doesn't already exist.
   * This function consumes the structure pointed at by dip, if not NULL.
   */
  int
  nfscl_adddevinfo(struct nfsmount *nmp, struct nfscldevinfo *dip, int ind,
      struct nfsclflayout *flp)
  {
          struct nfsclclient *clp;
          struct nfscldevinfo *tdip;
          uint8_t *dev;
  
          NFSLOCKCLSTATE();
          clp = nmp->nm_clp;
          if (clp == NULL) {
                  NFSUNLOCKCLSTATE();
                  if (dip != NULL)
                          free(dip, M_NFSDEVINFO);
                  return (ENODEV);
          }
          if ((flp->nfsfl_flags & NFSFL_FILE) != 0)
                  dev = flp->nfsfl_dev;
          else
                  dev = flp->nfsfl_ffm[ind].dev;
          tdip = nfscl_finddevinfo(clp, dev);
          if (tdip != NULL) {
                  tdip->nfsdi_layoutrefs++;
                  if ((flp->nfsfl_flags & NFSFL_FILE) != 0)
                          flp->nfsfl_devp = tdip;
                  else
                          flp->nfsfl_ffm[ind].devp = tdip;
                  nfscl_reldevinfo_locked(tdip);
                  NFSUNLOCKCLSTATE();
                  if (dip != NULL)
                          free(dip, M_NFSDEVINFO);
                  return (0);
          }
          if (dip != NULL) {
                  LIST_INSERT_HEAD(&clp->nfsc_devinfo, dip, nfsdi_list);
                  dip->nfsdi_layoutrefs = 1;
                  if ((flp->nfsfl_flags & NFSFL_FILE) != 0)
                          flp->nfsfl_devp = dip;
                  else
                          flp->nfsfl_ffm[ind].devp = dip;
          }
          NFSUNLOCKCLSTATE();
          if (dip == NULL)
                  return (ENODEV);
          return (0);
  }
  
  /*
   * Free up a layout structure and associated file layout structure(s).
   */
  void
  nfscl_freelayout(struct nfscllayout *layp)
  {
          struct nfsclflayout *flp, *nflp;
          struct nfsclrecalllayout *rp, *nrp;
  
          LIST_FOREACH_SAFE(flp, &layp->nfsly_flayread, nfsfl_list, nflp) {
                  LIST_REMOVE(flp, nfsfl_list);
                  nfscl_freeflayout(flp);
          }
          LIST_FOREACH_SAFE(flp, &layp->nfsly_flayrw, nfsfl_list, nflp) {
                  LIST_REMOVE(flp, nfsfl_list);
                  nfscl_freeflayout(flp);
          }
          LIST_FOREACH_SAFE(rp, &layp->nfsly_recall, nfsrecly_list, nrp) {
                  LIST_REMOVE(rp, nfsrecly_list);
                  free(rp, M_NFSLAYRECALL);
          }
          nfscl_layoutcnt--;
          nfsstatsv1.cllayouts--;
          free(layp, M_NFSLAYOUT);
  }
  
  /*
   * Free up a file layout structure.
   */
  void
  nfscl_freeflayout(struct nfsclflayout *flp)
  {
          int i, j;
  
          if ((flp->nfsfl_flags & NFSFL_FILE) != 0) {
                  for (i = 0; i < flp->nfsfl_fhcnt; i++)
                          free(flp->nfsfl_fh[i], M_NFSFH);
                  if (flp->nfsfl_devp != NULL)
                          flp->nfsfl_devp->nfsdi_layoutrefs--;
          }
          if ((flp->nfsfl_flags & NFSFL_FLEXFILE) != 0)
                  for (i = 0; i < flp->nfsfl_mirrorcnt; i++) {
                          for (j = 0; j < flp->nfsfl_ffm[i].fhcnt; j++)
                                  free(flp->nfsfl_ffm[i].fh[j], M_NFSFH);
                          if (flp->nfsfl_ffm[i].devp != NULL)     
                                  flp->nfsfl_ffm[i].devp->nfsdi_layoutrefs--;     
                  }
          free(flp, M_NFSFLAYOUT);
  }
  
  /*
   * Free up a file layout devinfo structure.
   */
  void