/*      $NetBSD: nfs_nfsdport.c,v 1.4 2021/03/29 02:13:38 simonb Exp $  */
/*-
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Rick Macklem at The University of Guelph.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <sys/cdefs.h>
/* __FBSDID("FreeBSD: head/sys/fs/nfsserver/nfs_nfsdport.c 308212 2016-11-02 12:43:15Z kib "); */
__RCSID("$NetBSD: nfs_nfsdport.c,v 1.4 2021/03/29 02:13:38 simonb Exp $");

#if 0
#include <sys/capsicum.h>
#endif

/*
 * Functions that perform the vfs operations required by the routines in
 * nfsd_serv.c. It is hoped that this change will make the server more
 * portable.
 */

#include <fs/nfs/common/nfsport.h>
#include <sys/hash.h>
#include <sys/sysctl.h>

#if 0
#include <nlm/nlm_prot.h>
#include <nlm/nlm.h>
#endif

FEATURE(nfsd, "NFSv4 server");

extern u_int32_t newnfs_true, newnfs_false, newnfs_xdrneg1;
extern int nfsrv_useacl;
extern int newnfs_numnfsd;
extern struct mount nfsv4root_mnt;
extern struct nfsrv_stablefirst nfsrv_stablefirst;
extern void (*nfsd_call_servertimer)(void);
extern SVCPOOL  *nfsrvd_pool;
extern struct nfsv4lock nfsd_suspend_lock;
extern struct nfsclienthashhead *nfsclienthash;
extern struct nfslockhashhead *nfslockhash;
extern struct nfssessionhash *nfssessionhash;
extern int nfsrv_sessionhashsize;
extern struct nfsstatsv1 nfsstatsv1;
struct vfsoptlist nfsv4root_opt, nfsv4root_newopt;
NFSDLOCKMUTEX;
struct nfsrchash_bucket nfsrchash_table[NFSRVCACHE_HASHSIZE];
struct nfsrchash_bucket nfsrcahash_table[NFSRVCACHE_HASHSIZE];
struct mtx nfsrc_udpmtx;
struct mtx nfs_v4root_mutex;
struct nfsrvfh nfs_rootfh, nfs_pubfh;
int nfs_pubfhset = 0, nfs_rootfhset = 0;
struct proc *nfsd_master_proc = NULL;
int nfsd_debuglevel = 0;
static pid_t nfsd_master_pid = (pid_t)-1;
static char nfsd_master_comm[MAXCOMLEN + 1];
static struct timeval nfsd_master_start;
static uint32_t nfsv4_sysid = 0;

static int nfssvc_srvcall(struct thread *, struct nfssvc_args *,
    struct ucred *);

int nfsrv_enable_crossmntpt = 1;
static int nfs_commit_blks;
static int nfs_commit_miss;
extern int nfsrv_issuedelegs;
extern int nfsrv_dolocallocks;
extern int nfsd_enable_stringtouid;

SYSCTL_NODE(_vfs, OID_AUTO, nfsd, CTLFLAG_RW, 0, "NFS server");
SYSCTL_INT(_vfs_nfsd, OID_AUTO, mirrormnt, CTLFLAG_RW,
    &nfsrv_enable_crossmntpt, 0, "Enable nfsd to cross mount points");
SYSCTL_INT(_vfs_nfsd, OID_AUTO, commit_blks, CTLFLAG_RW, &nfs_commit_blks,
    0, "");
SYSCTL_INT(_vfs_nfsd, OID_AUTO, commit_miss, CTLFLAG_RW, &nfs_commit_miss,
    0, "");
SYSCTL_INT(_vfs_nfsd, OID_AUTO, issue_delegations, CTLFLAG_RW,
    &nfsrv_issuedelegs, 0, "Enable nfsd to issue delegations");
SYSCTL_INT(_vfs_nfsd, OID_AUTO, enable_locallocks, CTLFLAG_RW,
    &nfsrv_dolocallocks, 0, "Enable nfsd to acquire local locks on files");
SYSCTL_INT(_vfs_nfsd, OID_AUTO, debuglevel, CTLFLAG_RW, &nfsd_debuglevel,
    0, "Debug level for NFS server");
SYSCTL_INT(_vfs_nfsd, OID_AUTO, enable_stringtouid, CTLFLAG_RW,
    &nfsd_enable_stringtouid, 0, "Enable nfsd to accept numeric owner_names");

#define MAX_REORDERED_RPC       16
#define NUM_HEURISTIC           1031
#define NHUSE_INIT              64
#define NHUSE_INC               16
#define NHUSE_MAX               2048

static struct nfsheur {
        struct vnode *nh_vp;    /* vp to match (unreferenced pointer) */
        off_t nh_nextoff;       /* next offset for sequential detection */
        int nh_use;             /* use count for selection */
        int nh_seqcount;        /* heuristic */
} nfsheur[NUM_HEURISTIC];


/*
 * Heuristic to detect sequential operation.
 */
static struct nfsheur *
nfsrv_sequential_heuristic(struct uio *uio, struct vnode *vp)
{
        struct nfsheur *nh;
        int hi, try;

        /* Locate best candidate. */
        try = 32;
        hi = ((int)(vaddr_t)vp / sizeof(struct vnode)) % NUM_HEURISTIC;
        nh = &nfsheur[hi];
        while (try--) {
                if (nfsheur[hi].nh_vp == vp) {
                        nh = &nfsheur[hi];
                        break;
                }
                if (nfsheur[hi].nh_use > 0)
                        --nfsheur[hi].nh_use;
                hi = (hi + 1) % NUM_HEURISTIC;
                if (nfsheur[hi].nh_use < nh->nh_use)
                        nh = &nfsheur[hi];
        }

        /* Initialize hint if this is a new file. */
        if (nh->nh_vp != vp) {
                nh->nh_vp = vp;
                nh->nh_nextoff = uio->uio_offset;
                nh->nh_use = NHUSE_INIT;
                if (uio->uio_offset == 0)
                        nh->nh_seqcount = 4;
                else
                        nh->nh_seqcount = 1;
        }

        /* Calculate heuristic. */
        if ((uio->uio_offset == 0 && nh->nh_seqcount > 0) ||
            uio->uio_offset == nh->nh_nextoff) {
                /* See comments in vfs_vnops.c:sequential_heuristic(). */
                nh->nh_seqcount += howmany(uio->uio_resid, 16384);
                if (nh->nh_seqcount > IO_SEQMAX)
                        nh->nh_seqcount = IO_SEQMAX;
        } else if (qabs(uio->uio_offset - nh->nh_nextoff) <= MAX_REORDERED_RPC *
            imax(vp->v_mount->mnt_stat.f_iosize, uio->uio_resid)) {
                /* Probably a reordered RPC, leave seqcount alone. */
        } else if (nh->nh_seqcount > 1) {
                nh->nh_seqcount /= 2;
        } else {
                nh->nh_seqcount = 0;
        }
        nh->nh_use += NHUSE_INC;
        if (nh->nh_use > NHUSE_MAX)
                nh->nh_use = NHUSE_MAX;
        return (nh);
}

/*
 * Get attributes into nfsvattr structure.
 */
int
nfsvno_getattr(struct vnode *vp, struct nfsvattr *nvap, struct ucred *cred,
    struct thread *p, int vpislocked)
{
        int error, lockedit = 0;

        if (vpislocked == 0) {
                /*
                 * When vpislocked == 0, the vnode is either exclusively
                 * locked by this thread or not locked by this thread.
                 * As such, shared lock it, if not exclusively locked.
                 */
                if (NFSVOPISLOCKED(vp) != LK_EXCLUSIVE) {
                        lockedit = 1;
                        NFSVOPLOCK(vp, LK_SHARED | LK_RETRY);
                }
        }
        error = VOP_GETATTR(vp, &nvap->na_vattr, cred);
        if (lockedit != 0)
                NFSVOPUNLOCK(vp, 0);

        NFSEXITCODE(error);
        return (error);
}

/*
 * Get a file handle for a vnode.
 */
int
nfsvno_getfh(struct vnode *vp, fhandle_t *fhp, struct thread *p)
{
        int error;

        NFSBZERO((caddr_t)fhp, sizeof(fhandle_t));
        fhp->fh_fsid = vp->v_mount->mnt_stat.f_fsid;
        error = VOP_VPTOFH(vp, &fhp->fh_fid);

        NFSEXITCODE(error);
        return (error);
}

/*
 * Perform access checking for vnodes obtained from file handles that would
 * refer to files already opened by a Unix client. You cannot just use
 * vn_writechk() and VOP_ACCESSX() for two reasons.
 * 1 - You must check for exported rdonly as well as MNT_RDONLY for the write
 *     case.
 * 2 - The owner is to be given access irrespective of mode bits for some
 *     operations, so that processes that chmod after opening a file don't
 *     break.
 */
int
nfsvno_accchk(struct vnode *vp, accmode_t accmode, struct ucred *cred,
    struct nfsexstuff *exp, struct thread *p, int override, int vpislocked,
    u_int32_t *supportedtypep)
{
        struct vattr vattr;
        int error = 0, getret = 0;

        if (vpislocked == 0) {
                if (NFSVOPLOCK(vp, LK_SHARED) != 0) {
                        error = EPERM;
                        goto out;
                }
        }
        if (accmode & VWRITE) {
                /* Just vn_writechk() changed to check rdonly */
                /*
                 * Disallow write attempts on read-only file systems;
                 * unless the file is a socket or a block or character
                 * device resident on the file system.
                 */
                if (NFSVNO_EXRDONLY(exp) ||
                    (vp->v_mount->mnt_flag & MNT_RDONLY)) {
                        switch (vp->v_type) {
                        case VREG:
                        case VDIR:
                        case VLNK:
                                error = EROFS;
                        default:
                                break;
                        }
                }
                /*
                 * If there's shared text associated with
                 * the inode, try to free it up once.  If
                 * we fail, we can't allow writing.
                 */
                if (VOP_IS_TEXT(vp) && error == 0)
                        error = ETXTBSY;
        }
        if (error != 0) {
                if (vpislocked == 0)
                        NFSVOPUNLOCK(vp, 0);
                goto out;
        }

        /*
         * Should the override still be applied when ACLs are enabled?
         */
        error = VOP_ACCESSX(vp, accmode, cred, p);
        if (error != 0 && (accmode & (VDELETE | VDELETE_CHILD))) {
                /*
                 * Try again with VEXPLICIT_DENY, to see if the test for
                 * deletion is supported.
                 */
                error = VOP_ACCESSX(vp, accmode | VEXPLICIT_DENY, cred, p);
                if (error == 0) {
                        if (vp->v_type == VDIR) {
                                accmode &= ~(VDELETE | VDELETE_CHILD);
                                accmode |= VWRITE;
                                error = VOP_ACCESSX(vp, accmode, cred, p);
                        } else if (supportedtypep != NULL) {
                                *supportedtypep &= ~NFSACCESS_DELETE;
                        }
                }
        }

        /*
         * Allow certain operations for the owner (reads and writes
         * on files that are already open).
         */
        if (override != NFSACCCHK_NOOVERRIDE &&
            (error == EPERM || error == EACCES)) {
                if (cred->cr_uid == 0 && (override & NFSACCCHK_ALLOWROOT))
                        error = 0;
                else if (override & NFSACCCHK_ALLOWOWNER) {
                        getret = VOP_GETATTR(vp, &vattr, cred);
                        if (getret == 0 && cred->cr_uid == vattr.va_uid)
                                error = 0;
                }
        }
        if (vpislocked == 0)
                NFSVOPUNLOCK(vp, 0);

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

/*
 * Set attribute(s) vnop.
 */
int
nfsvno_setattr(struct vnode *vp, struct nfsvattr *nvap, struct ucred *cred,
    struct thread *p, struct nfsexstuff *exp)
{
        int error;

        error = VOP_SETATTR(vp, &nvap->na_vattr, cred);
        NFSEXITCODE(error);
        return (error);
}

/*
 * Set up nameidata for a lookup() call and do it.
 */
int
nfsvno_namei(struct nfsrv_descript *nd, struct nameidata *ndp,
    struct vnode *dp, int islocked, struct nfsexstuff *exp, struct thread *p,
    struct vnode **retdirp)
{
        struct componentname *cnp = &ndp->ni_cnd;
        int i;
        struct iovec aiov;
        struct uio auio;
        int lockleaf = (cnp->cn_flags & LOCKLEAF) != 0, linklen;
        int error = 0, crossmnt;
        char *cp;

        *retdirp = NULL;
        cnp->cn_nameptr = cnp->cn_pnbuf;
        ndp->ni_lcf = 0;
        /*
         * Extract and set starting directory.
         */
        if (dp->v_type != VDIR) {
                if (islocked)
                        vput(dp);
                else
                        vrele(dp);
                nfsvno_relpathbuf(ndp);
                error = ENOTDIR;
                goto out1;
        }
        if (islocked)
                NFSVOPUNLOCK(dp, 0);
        VREF(dp);
        *retdirp = dp;
        if (NFSVNO_EXRDONLY(exp))
                cnp->cn_flags |= RDONLY;
        ndp->ni_segflg = UIO_SYSSPACE;
        crossmnt = 1;

        if (nd->nd_flag & ND_PUBLOOKUP) {
                ndp->ni_loopcnt = 0;
                if (cnp->cn_pnbuf[0] == '/') {
                        vrele(dp);
                        /*
                         * Check for degenerate pathnames here, since lookup()
                         * panics on them.
                         */
                        for (i = 1; i < ndp->ni_pathlen; i++)
                                if (cnp->cn_pnbuf[i] != '/')
                                        break;
                        if (i == ndp->ni_pathlen) {
                                error = NFSERR_ACCES;
                                goto out;
                        }
                        dp = rootvnode;
                        VREF(dp);
                }
        } else if ((nfsrv_enable_crossmntpt == 0 && NFSVNO_EXPORTED(exp)) ||
            (nd->nd_flag & ND_NFSV4) == 0) {
                /*
                 * Only cross mount points for NFSv4 when doing a
                 * mount while traversing the file system above
                 * the mount point, unless nfsrv_enable_crossmntpt is set.
                 */
                cnp->cn_flags |= NOCROSSMOUNT;
                crossmnt = 0;
        }

        /*
         * Initialize for scan, set ni_startdir and bump ref on dp again
         * because lookup() will dereference ni_startdir.
         */

        cnp->cn_thread = p;
        ndp->ni_startdir = dp;
        ndp->ni_rootdir = rootvnode;
        ndp->ni_topdir = NULL;

        if (!lockleaf)
                cnp->cn_flags |= LOCKLEAF;
        for (;;) {
                cnp->cn_nameptr = cnp->cn_pnbuf;
                /*
                 * Call lookup() to do the real work.  If an error occurs,
                 * ndp->ni_vp and ni_dvp are left uninitialized or NULL and
                 * we do not have to dereference anything before returning.
                 * In either case ni_startdir will be dereferenced and NULLed
                 * out.
                 */
                error = lookup(ndp);
                if (error)
                        break;

                /*
                 * Check for encountering a symbolic link.  Trivial
                 * termination occurs if no symlink encountered.
                 */
                if ((cnp->cn_flags & ISSYMLINK) == 0) {
                        if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0)
                                nfsvno_relpathbuf(ndp);
                        if (ndp->ni_vp && !lockleaf)
                                NFSVOPUNLOCK(ndp->ni_vp, 0);
                        break;
                }

                /*
                 * Validate symlink
                 */
                if ((cnp->cn_flags & LOCKPARENT) && ndp->ni_pathlen == 1)
                        NFSVOPUNLOCK(ndp->ni_dvp, 0);
                if (!(nd->nd_flag & ND_PUBLOOKUP)) {
                        error = EINVAL;
                        goto badlink2;
                }

                if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
                        error = ELOOP;
                        goto badlink2;
                }
                if (ndp->ni_pathlen > 1)
                        cp = uma_zalloc(namei_zone, M_WAITOK);
                else
                        cp = cnp->cn_pnbuf;
                aiov.iov_base = cp;
                aiov.iov_len = MAXPATHLEN;
                auio.uio_iov = &aiov;
                auio.uio_iovcnt = 1;
                auio.uio_offset = 0;
                auio.uio_rw = UIO_READ;
                auio.uio_segflg = UIO_SYSSPACE;
                auio.uio_td = NULL;
                auio.uio_resid = MAXPATHLEN;
                error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred);
                if (error) {
                badlink1:
                        if (ndp->ni_pathlen > 1)
                                uma_zfree(namei_zone, cp);
                badlink2:
                        vrele(ndp->ni_dvp);
                        vput(ndp->ni_vp);
                        break;
                }
                linklen = MAXPATHLEN - auio.uio_resid;
                if (linklen == 0) {
                        error = ENOENT;
                        goto badlink1;
                }
                if (linklen + ndp->ni_pathlen >= MAXPATHLEN) {
                        error = ENAMETOOLONG;
                        goto badlink1;
                }

                /*
                 * Adjust or replace path
                 */
                if (ndp->ni_pathlen > 1) {
                        NFSBCOPY(ndp->ni_next, cp + linklen, ndp->ni_pathlen);
                        uma_zfree(namei_zone, cnp->cn_pnbuf);
                        cnp->cn_pnbuf = cp;
                } else
                        cnp->cn_pnbuf[linklen] = '\0';
                ndp->ni_pathlen += linklen;

                /*
                 * Cleanup refs for next loop and check if root directory
                 * should replace current directory.  Normally ni_dvp
                 * becomes the new base directory and is cleaned up when
                 * we loop.  Explicitly null pointers after invalidation
                 * to clarify operation.
                 */
                vput(ndp->ni_vp);
                ndp->ni_vp = NULL;

                if (cnp->cn_pnbuf[0] == '/') {
                        vrele(ndp->ni_dvp);
                        ndp->ni_dvp = ndp->ni_rootdir;
                        VREF(ndp->ni_dvp);
                }
                ndp->ni_startdir = ndp->ni_dvp;
                ndp->ni_dvp = NULL;
        }
        if (!lockleaf)
                cnp->cn_flags &= ~LOCKLEAF;

out:
        if (error) {
                nfsvno_relpathbuf(ndp);
                ndp->ni_vp = NULL;
                ndp->ni_dvp = NULL;
                ndp->ni_startdir = NULL;
        } else if ((ndp->ni_cnd.cn_flags & (WANTPARENT|LOCKPARENT)) == 0) {
                ndp->ni_dvp = NULL;
        }

out1:
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Set up a pathname buffer and return a pointer to it and, optionally
 * set a hash pointer.
 */
void
nfsvno_setpathbuf(struct nameidata *ndp, char **bufpp, u_long **hashpp)
{
        struct componentname *cnp = &ndp->ni_cnd;

        cnp->cn_flags |= (NOMACCHECK | HASBUF);
        cnp->cn_pnbuf = uma_zalloc(namei_zone, M_WAITOK);
        if (hashpp != NULL)
                *hashpp = NULL;
        *bufpp = cnp->cn_pnbuf;
}

/*
 * Release the above path buffer, if not released by nfsvno_namei().
 */
void
nfsvno_relpathbuf(struct nameidata *ndp)
{

        if ((ndp->ni_cnd.cn_flags & HASBUF) == 0)
                panic("nfsrelpath");
        uma_zfree(namei_zone, ndp->ni_cnd.cn_pnbuf);
        ndp->ni_cnd.cn_flags &= ~HASBUF;
}

/*
 * Readlink vnode op into an mbuf list.
 */
int
nfsvno_readlink(struct vnode *vp, struct ucred *cred, struct thread *p,
    struct mbuf **mpp, struct mbuf **mpendp, int *lenp)
{
        struct iovec iv[(NFS_MAXPATHLEN+MLEN-1)/MLEN];
        struct iovec *ivp = iv;
        struct uio io, *uiop = &io;
        struct mbuf *mp, *mp2 = NULL, *mp3 = NULL;
        int i, len, tlen, error = 0;

        len = 0;
        i = 0;
        while (len < NFS_MAXPATHLEN) {
                NFSMGET(mp);
                MCLGET(mp, M_WAITOK);
                mp->m_len = M_SIZE(mp);
                if (len == 0) {
                        mp3 = mp2 = mp;
                } else {
                        mp2->m_next = mp;
                        mp2 = mp;
                }
                if ((len + mp->m_len) > NFS_MAXPATHLEN) {
                        mp->m_len = NFS_MAXPATHLEN - len;
                        len = NFS_MAXPATHLEN;
                } else {
                        len += mp->m_len;
                }
                ivp->iov_base = mtod(mp, caddr_t);
                ivp->iov_len = mp->m_len;
                i++;
                ivp++;
        }
        uiop->uio_iov = iv;
        uiop->uio_iovcnt = i;
        uiop->uio_offset = 0;
        uiop->uio_resid = len;
        uiop->uio_rw = UIO_READ;
        uiop->uio_segflg = UIO_SYSSPACE;
        uiop->uio_td = NULL;
        error = VOP_READLINK(vp, uiop, cred);
        if (error) {
                m_freem(mp3);
                *lenp = 0;
                goto out;
        }
        if (uiop->uio_resid > 0) {
                len -= uiop->uio_resid;
                tlen = NFSM_RNDUP(len);
                nfsrv_adj(mp3, NFS_MAXPATHLEN - tlen, tlen - len);
        }
        *lenp = len;
        *mpp = mp3;
        *mpendp = mp;

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

/*
 * Read vnode op call into mbuf list.
 */
int
nfsvno_read(struct vnode *vp, off_t off, int cnt, struct ucred *cred,
    struct thread *p, struct mbuf **mpp, struct mbuf **mpendp)
{
        struct mbuf *m;
        int i;
        struct iovec *iv;
        struct iovec *iv2;
        int error = 0, len, left, siz, tlen, ioflag = 0;
        struct mbuf *m2 = NULL, *m3;
        struct uio io, *uiop = &io;
        struct nfsheur *nh;

        len = left = NFSM_RNDUP(cnt);
        m3 = NULL;
        /*
         * Generate the mbuf list with the uio_iov ref. to it.
         */
        i = 0;
        while (left > 0) {
                NFSMGET(m);
                MCLGET(m, M_WAITOK);
                m->m_len = 0;
                siz = uimin(M_TRAILINGSPACE(m), left);
                left -= siz;
                i++;
                if (m3)
                        m2->m_next = m;
                else
                        m3 = m;
                m2 = m;
        }
        MALLOC(iv, struct iovec *, i * sizeof (struct iovec),
            M_TEMP, M_WAITOK);
        uiop->uio_iov = iv2 = iv;
        m = m3;
        left = len;
        i = 0;
        while (left > 0) {
                if (m == NULL)
                        panic("nfsvno_read iov");
                siz = uimin(M_TRAILINGSPACE(m), left);
                if (siz > 0) {
                        iv->iov_base = mtod(m, caddr_t) + m->m_len;
                        iv->iov_len = siz;
                        m->m_len += siz;
                        left -= siz;
                        iv++;
                        i++;
                }
                m = m->m_next;
        }
        uiop->uio_iovcnt = i;
        uiop->uio_offset = off;
        uiop->uio_resid = len;
        uiop->uio_rw = UIO_READ;
        uiop->uio_segflg = UIO_SYSSPACE;
        uiop->uio_td = NULL;
        nh = nfsrv_sequential_heuristic(uiop, vp);
        ioflag |= nh->nh_seqcount << IO_SEQSHIFT;
        /* XXX KDM make this more systematic? */
        nfsstatsv1.srvbytes[NFSV4OP_READ] += uiop->uio_resid;
        error = VOP_READ(vp, uiop, IO_NODELOCKED | ioflag, cred);
        FREE((caddr_t)iv2, M_TEMP);
        if (error) {
                m_freem(m3);
                *mpp = NULL;
                goto out;
        }
        nh->nh_nextoff = uiop->uio_offset;
        tlen = len - uiop->uio_resid;
        cnt = cnt < tlen ? cnt : tlen;
        tlen = NFSM_RNDUP(cnt);
        if (tlen == 0) {
                m_freem(m3);
                m3 = NULL;
        } else if (len != tlen || tlen != cnt)
                nfsrv_adj(m3, len - tlen, tlen - cnt);
        *mpp = m3;
        *mpendp = m2;

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

/*
 * Write vnode op from an mbuf list.
 */
int
nfsvno_write(struct vnode *vp, off_t off, int retlen, int cnt, int stable,
    struct mbuf *mp, char *cp, struct ucred *cred, struct thread *p)
{
        struct iovec *ivp;
        int i, len;
        struct iovec *iv;
        int ioflags, error;
        struct uio io, *uiop = &io;
        struct nfsheur *nh;

        MALLOC(ivp, struct iovec *, cnt * sizeof (struct iovec), M_TEMP,
            M_WAITOK);
        uiop->uio_iov = iv = ivp;
        uiop->uio_iovcnt = cnt;
        i = mtod(mp, caddr_t) + mp->m_len - cp;
        len = retlen;
        while (len > 0) {
                if (mp == NULL)
                        panic("nfsvno_write");
                if (i > 0) {
                        i = uimin(i, len);
                        ivp->iov_base = cp;
                        ivp->iov_len = i;
                        ivp++;
                        len -= i;
                }
                mp = mp->m_next;
                if (mp) {
                        i = mp->m_len;
                        cp = mtod(mp, caddr_t);
                }
        }

        if (stable == NFSWRITE_UNSTABLE)
                ioflags = IO_NODELOCKED;
        else
                ioflags = (IO_SYNC | IO_NODELOCKED);
        uiop->uio_resid = retlen;
        uiop->uio_rw = UIO_WRITE;
        uiop->uio_segflg = UIO_SYSSPACE;
        NFSUIOPROC(uiop, p);
        uiop->uio_offset = off;
        nh = nfsrv_sequential_heuristic(uiop, vp);
        ioflags |= nh->nh_seqcount << IO_SEQSHIFT;
        /* XXX KDM make this more systematic? */
        nfsstatsv1.srvbytes[NFSV4OP_WRITE] += uiop->uio_resid;
        error = VOP_WRITE(vp, uiop, ioflags, cred);
        if (error == 0)
                nh->nh_nextoff = uiop->uio_offset;
        FREE((caddr_t)iv, M_TEMP);

        NFSEXITCODE(error);
        return (error);
}

/*
 * Common code for creating a regular file (plus special files for V2).
 */
int
nfsvno_createsub(struct nfsrv_descript *nd, struct nameidata *ndp,
    struct vnode **vpp, struct nfsvattr *nvap, int *exclusive_flagp,
    int32_t *cverf, NFSDEV_T rdev, struct thread *p, struct nfsexstuff *exp)
{
        u_quad_t tempsize;
        int error;

        error = nd->nd_repstat;
        if (!error && ndp->ni_vp == NULL) {
                if (nvap->na_type == VREG || nvap->na_type == VSOCK) {
                        vrele(ndp->ni_startdir);
                        error = VOP_CREATE(ndp->ni_dvp,
                            &ndp->ni_vp, &ndp->ni_cnd, &nvap->na_vattr);
                        vput(ndp->ni_dvp);
                        nfsvno_relpathbuf(ndp);
                        if (!error) {
                                if (*exclusive_flagp) {
                                        *exclusive_flagp = 0;
                                        NFSVNO_ATTRINIT(nvap);
                                        nvap->na_atime.tv_sec = cverf[0];
                                        nvap->na_atime.tv_nsec = cverf[1];
                                        error = VOP_SETATTR(ndp->ni_vp,
                                            &nvap->na_vattr, nd->nd_cred);
                                        if (error != 0) {
                                                vput(ndp->ni_vp);
                                                ndp->ni_vp = NULL;
                                                error = NFSERR_NOTSUPP;
                                        }
                                }
                        }
                /*
                 * NFS V2 Only. nfsrvd_mknod() does this for V3.
                 * (This implies, just get out on an error.)
                 */
                } else if (nvap->na_type == VCHR || nvap->na_type == VBLK ||
                        nvap->na_type == VFIFO) {
                        if (nvap->na_type == VCHR && rdev == 0xffffffff)
                                nvap->na_type = VFIFO;
                        if (nvap->na_type != VFIFO &&
                            (error = priv_check_cred(nd->nd_cred,
                             PRIV_VFS_MKNOD_DEV, 0))) {
                                vrele(ndp->ni_startdir);
                                nfsvno_relpathbuf(ndp);
                                vput(ndp->ni_dvp);
                                goto out;
                        }
                        nvap->na_rdev = rdev;
                        error = VOP_MKNOD(ndp->ni_dvp, &ndp->ni_vp,
                            &ndp->ni_cnd, &nvap->na_vattr);
                        vput(ndp->ni_dvp);
                        nfsvno_relpathbuf(ndp);
                        vrele(ndp->ni_startdir);
                        if (error)
                                goto out;
                } else {
                        vrele(ndp->ni_startdir);
                        nfsvno_relpathbuf(ndp);
                        vput(ndp->ni_dvp);
                        error = ENXIO;
                        goto out;
                }
                *vpp = ndp->ni_vp;
        } else {
                /*
                 * Handle cases where error is already set and/or
                 * the file exists.
                 * 1 - clean up the lookup
                 * 2 - iff !error and na_size set, truncate it
                 */
                vrele(ndp->ni_startdir);
                nfsvno_relpathbuf(ndp);
                *vpp = ndp->ni_vp;
                if (ndp->ni_dvp == *vpp)
                        vrele(ndp->ni_dvp);
                else
                        vput(ndp->ni_dvp);
                if (!error && nvap->na_size != VNOVAL) {
                        error = nfsvno_accchk(*vpp, VWRITE,
                            nd->nd_cred, exp, p, NFSACCCHK_NOOVERRIDE,
                            NFSACCCHK_VPISLOCKED, NULL);
                        if (!error) {
                                tempsize = nvap->na_size;
                                NFSVNO_ATTRINIT(nvap);
                                nvap->na_size = tempsize;
                                error = VOP_SETATTR(*vpp,
                                    &nvap->na_vattr, nd->nd_cred);
                        }
                }
                if (error)
                        vput(*vpp);
        }

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

/*
 * Do a mknod vnode op.
 */
int
nfsvno_mknod(struct nameidata *ndp, struct nfsvattr *nvap, struct ucred *cred,
    struct thread *p)
{
        int error = 0;
        enum vtype vtyp;

        vtyp = nvap->na_type;
        /*
         * Iff doesn't exist, create it.
         */
        if (ndp->ni_vp) {
                vrele(ndp->ni_startdir);
                nfsvno_relpathbuf(ndp);
                vput(ndp->ni_dvp);
                vrele(ndp->ni_vp);
                error = EEXIST;
                goto out;
        }
        if (vtyp != VCHR && vtyp != VBLK && vtyp != VSOCK && vtyp != VFIFO) {
                vrele(ndp->ni_startdir);
                nfsvno_relpathbuf(ndp);
                vput(ndp->ni_dvp);
                error = NFSERR_BADTYPE;
                goto out;
        }
        if (vtyp == VSOCK) {
                vrele(ndp->ni_startdir);
                error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp,
                    &ndp->ni_cnd, &nvap->na_vattr);
                vput(ndp->ni_dvp);
                nfsvno_relpathbuf(ndp);
        } else {
                if (nvap->na_type != VFIFO &&
                    (error = priv_check_cred(cred, PRIV_VFS_MKNOD_DEV, 0))) {
                        vrele(ndp->ni_startdir);
                        nfsvno_relpathbuf(ndp);
                        vput(ndp->ni_dvp);
                        goto out;
                }
                error = VOP_MKNOD(ndp->ni_dvp, &ndp->ni_vp,
                    &ndp->ni_cnd, &nvap->na_vattr);
                vput(ndp->ni_dvp);
                nfsvno_relpathbuf(ndp);
                vrele(ndp->ni_startdir);
                /*
                 * Since VOP_MKNOD returns the ni_vp, I can't
                 * see any reason to do the lookup.
                 */
        }

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

/*
 * Mkdir vnode op.
 */
int
nfsvno_mkdir(struct nameidata *ndp, struct nfsvattr *nvap, uid_t saved_uid,
    struct ucred *cred, struct thread *p, struct nfsexstuff *exp)
{
        int error = 0;

        if (ndp->ni_vp != NULL) {
                if (ndp->ni_dvp == ndp->ni_vp)
                        vrele(ndp->ni_dvp);
                else
                        vput(ndp->ni_dvp);
                vrele(ndp->ni_vp);
                nfsvno_relpathbuf(ndp);
                error = EEXIST;
                goto out;
        }
        error = VOP_MKDIR(ndp->ni_dvp, &ndp->ni_vp, &ndp->ni_cnd,
            &nvap->na_vattr);
        vput(ndp->ni_dvp);
        nfsvno_relpathbuf(ndp);

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

/*
 * symlink vnode op.
 */
int
nfsvno_symlink(struct nameidata *ndp, struct nfsvattr *nvap, char *pathcp,
    int pathlen, int not_v2, uid_t saved_uid, struct ucred *cred, struct thread *p,
    struct nfsexstuff *exp)
{
        int error = 0;

        if (ndp->ni_vp) {
                vrele(ndp->ni_startdir);
                nfsvno_relpathbuf(ndp);
                if (ndp->ni_dvp == ndp->ni_vp)
                        vrele(ndp->ni_dvp);
                else
                        vput(ndp->ni_dvp);
                vrele(ndp->ni_vp);
                error = EEXIST;
                goto out;
        }

        error = VOP_SYMLINK(ndp->ni_dvp, &ndp->ni_vp, &ndp->ni_cnd,
            &nvap->na_vattr, pathcp);
        vput(ndp->ni_dvp);
        vrele(ndp->ni_startdir);
        nfsvno_relpathbuf(ndp);
        /*
         * Although FreeBSD still had the lookup code in
         * it for 7/current, there doesn't seem to be any
         * point, since VOP_SYMLINK() returns the ni_vp.
         * Just vput it for v2.
         */
        if (!not_v2 && !error)
                vput(ndp->ni_vp);

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

/*
 * Parse symbolic link arguments.
 * This function has an ugly side effect. It will MALLOC() an area for
 * the symlink and set iov_base to point to it, only if it succeeds.
 * So, if it returns with uiop->uio_iov->iov_base != NULL, that must
 * be FREE'd later.
 */
int
nfsvno_getsymlink(struct nfsrv_descript *nd, struct nfsvattr *nvap,
    struct thread *p, char **pathcpp, int *lenp)
{
        u_int32_t *tl;
        char *pathcp = NULL;
        int error = 0, len;
        struct nfsv2_sattr *sp;

        *pathcpp = NULL;
        *lenp = 0;
        if ((nd->nd_flag & ND_NFSV3) &&
            (error = nfsrv_sattr(nd, NULL, nvap, NULL, NULL, p)))
                goto nfsmout;
        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
        len = fxdr_unsigned(int, *tl);
        if (len > NFS_MAXPATHLEN || len <= 0) {
                error = EBADRPC;
                goto nfsmout;
        }
        MALLOC(pathcp, caddr_t, len + 1, M_TEMP, M_WAITOK);
        error = nfsrv_mtostr(nd, pathcp, len);
        if (error)
                goto nfsmout;
        if (nd->nd_flag & ND_NFSV2) {
                NFSM_DISSECT(sp, struct nfsv2_sattr *, NFSX_V2SATTR);
                nvap->na_mode = fxdr_unsigned(u_int16_t, sp->sa_mode);
        }
        *pathcpp = pathcp;
        *lenp = len;
        NFSEXITCODE2(0, nd);
        return (0);
nfsmout:
        if (pathcp)
                free(pathcp, M_TEMP);
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Remove a non-directory object.
 */
int
nfsvno_removesub(struct nameidata *ndp, int is_v4, struct ucred *cred,
    struct thread *p, struct nfsexstuff *exp)
{
        struct vnode *vp;
        int error = 0;

        vp = ndp->ni_vp;
        if (vp->v_type == VDIR)
                error = NFSERR_ISDIR;
        else if (is_v4)
                error = nfsrv_checkremove(vp, 1, p);
        if (!error)
                error = VOP_REMOVE(ndp->ni_dvp, vp, &ndp->ni_cnd);
        if (ndp->ni_dvp == vp)
                vrele(ndp->ni_dvp);
        else
                vput(ndp->ni_dvp);
        vput(vp);
        if ((ndp->ni_cnd.cn_flags & SAVENAME) != 0)
                nfsvno_relpathbuf(ndp);
        NFSEXITCODE(error);
        return (error);
}

/*
 * Remove a directory.
 */
int
nfsvno_rmdirsub(struct nameidata *ndp, int is_v4, struct ucred *cred,
    struct thread *p, struct nfsexstuff *exp)
{
        struct vnode *vp;
        int error = 0;

        vp = ndp->ni_vp;
        if (vp->v_type != VDIR) {
                error = ENOTDIR;
                goto out;
        }
        /*
         * No rmdir "." please.
         */
        if (ndp->ni_dvp == vp) {
                error = EINVAL;
                goto out;
        }
        /*
         * The root of a mounted filesystem cannot be deleted.
         */
        if (vp->v_vflag & VV_ROOT)
                error = EBUSY;
out:
        if (!error)
                error = VOP_RMDIR(ndp->ni_dvp, vp, &ndp->ni_cnd);
        if (ndp->ni_dvp == vp)
                vrele(ndp->ni_dvp);
        else
                vput(ndp->ni_dvp);
        vput(vp);
        if ((ndp->ni_cnd.cn_flags & SAVENAME) != 0)
                nfsvno_relpathbuf(ndp);
        NFSEXITCODE(error);
        return (error);
}

/*
 * Rename vnode op.
 */
int
nfsvno_rename(struct nameidata *fromndp, struct nameidata *tondp,
    u_int32_t ndstat, u_int32_t ndflag, struct ucred *cred, struct thread *p)
{
        struct vnode *fvp, *tvp, *tdvp;
        int error = 0;

        fvp = fromndp->ni_vp;
        if (ndstat) {
                vrele(fromndp->ni_dvp);
                vrele(fvp);
                error = ndstat;
                goto out1;
        }
        tdvp = tondp->ni_dvp;
        tvp = tondp->ni_vp;
        if (tvp != NULL) {
                if (fvp->v_type == VDIR && tvp->v_type != VDIR) {
                        error = (ndflag & ND_NFSV2) ? EISDIR : EEXIST;
                        goto out;
                } else if (fvp->v_type != VDIR && tvp->v_type == VDIR) {
                        error = (ndflag & ND_NFSV2) ? ENOTDIR : EEXIST;
                        goto out;
                }
                if (tvp->v_type == VDIR && tvp->v_mountedhere) {
                        error = (ndflag & ND_NFSV2) ? ENOTEMPTY : EXDEV;
                        goto out;
                }

                /*
                 * A rename to '.' or '..' results in a prematurely
                 * unlocked vnode on FreeBSD5, so I'm just going to fail that
                 * here.
                 */
                if ((tondp->ni_cnd.cn_namelen == 1 &&
                     tondp->ni_cnd.cn_nameptr[0] == '.') ||
                    (tondp->ni_cnd.cn_namelen == 2 &&
                     tondp->ni_cnd.cn_nameptr[0] == '.' &&
                     tondp->ni_cnd.cn_nameptr[1] == '.')) {
                        error = EINVAL;
                        goto out;
                }
        }
        if (fvp->v_type == VDIR && fvp->v_mountedhere) {
                error = (ndflag & ND_NFSV2) ? ENOTEMPTY : EXDEV;
                goto out;
        }
        if (fvp->v_mount != tdvp->v_mount) {
                error = (ndflag & ND_NFSV2) ? ENOTEMPTY : EXDEV;
                goto out;
        }
        if (fvp == tdvp) {
                error = (ndflag & ND_NFSV2) ? ENOTEMPTY : EINVAL;
                goto out;
        }
        if (fvp == tvp) {
                /*
                 * If source and destination are the same, there is nothing to
                 * do. Set error to -1 to indicate this.
                 */
                error = -1;
                goto out;
        }
        if (ndflag & ND_NFSV4) {
                if (NFSVOPLOCK(fvp, LK_EXCLUSIVE) == 0) {
                        error = nfsrv_checkremove(fvp, 0, p);
                        NFSVOPUNLOCK(fvp, 0);
                } else
                        error = EPERM;
                if (tvp && !error)
                        error = nfsrv_checkremove(tvp, 1, p);
        } else {
                /*
                 * For NFSv2 and NFSv3, try to get rid of the delegation, so
                 * that the NFSv4 client won't be confused by the rename.
                 * Since nfsd_recalldelegation() can only be called on an
                 * unlocked vnode at this point and fvp is the file that will
                 * still exist after the rename, just do fvp.
                 */
                nfsd_recalldelegation(fvp, p);
        }
out:
        if (!error) {
                error = VOP_RENAME(fromndp->ni_dvp, fromndp->ni_vp,
                    &fromndp->ni_cnd, tondp->ni_dvp, tondp->ni_vp,
                    &tondp->ni_cnd);
        } else {
                if (tdvp == tvp)
                        vrele(tdvp);
                else
                        vput(tdvp);
                if (tvp)
                        vput(tvp);
                vrele(fromndp->ni_dvp);
                vrele(fvp);
                if (error == -1)
                        error = 0;
        }
        vrele(tondp->ni_startdir);
        nfsvno_relpathbuf(tondp);
out1:
        vrele(fromndp->ni_startdir);
        nfsvno_relpathbuf(fromndp);
        NFSEXITCODE(error);
        return (error);
}

/*
 * Link vnode op.
 */
int
nfsvno_link(struct nameidata *ndp, struct vnode *vp, struct ucred *cred,
    struct thread *p, struct nfsexstuff *exp)
{
        struct vnode *xp;
        int error = 0;

        xp = ndp->ni_vp;
        if (xp != NULL) {
                error = EEXIST;
        } else {
                xp = ndp->ni_dvp;
                if (vp->v_mount != xp->v_mount)
                        error = EXDEV;
        }
        if (!error) {
                NFSVOPLOCK(vp, LK_EXCLUSIVE | LK_RETRY);
                if ((vp->v_iflag & VI_DOOMED) == 0)
                        error = VOP_LINK(ndp->ni_dvp, vp, &ndp->ni_cnd);
                else
                        error = EPERM;
                if (ndp->ni_dvp == vp)
                        vrele(ndp->ni_dvp);
                else
                        vput(ndp->ni_dvp);
                NFSVOPUNLOCK(vp, 0);
        } else {
                if (ndp->ni_dvp == ndp->ni_vp)
                        vrele(ndp->ni_dvp);
                else
                        vput(ndp->ni_dvp);
                if (ndp->ni_vp)
                        vrele(ndp->ni_vp);
        }
        nfsvno_relpathbuf(ndp);
        NFSEXITCODE(error);
        return (error);
}

/*
 * Do the fsync() appropriate for the commit.
 */
int
nfsvno_fsync(struct vnode *vp, u_int64_t off, int cnt, struct ucred *cred,
    struct thread *td)
{
        int error = 0;

        /*
         * RFC 1813 3.3.21: if count is 0, a flush from offset to the end of
         * file is done.  At this time VOP_FSYNC does not accept offset and
         * byte count parameters so call VOP_FSYNC the whole file for now.
         * The same is true for NFSv4: RFC 3530 Sec. 14.2.3.
         * File systems that do not use the buffer cache (as indicated
         * by MNTK_USES_BCACHE not being set) must use VOP_FSYNC().
         */
        if (cnt == 0 || cnt > MAX_COMMIT_COUNT ||
            (vp->v_mount->mnt_kern_flag & MNTK_USES_BCACHE) == 0) {
                /*
                 * Give up and do the whole thing
                 */
                if (vp->v_object &&
                   (vp->v_object->flags & OBJ_MIGHTBEDIRTY)) {
                        VM_OBJECT_WLOCK(vp->v_object);
                        vm_object_page_clean(vp->v_object, 0, 0, OBJPC_SYNC);
                        VM_OBJECT_WUNLOCK(vp->v_object);
                }
                error = VOP_FSYNC(vp, MNT_WAIT, td);
        } else {
                /*
                 * Locate and synchronously write any buffers that fall
                 * into the requested range.  Note:  we are assuming that
                 * f_iosize is a power of 2.
                 */
                int iosize = vp->v_mount->mnt_stat.f_iosize;
                int iomask = iosize - 1;
                struct bufobj *bo;
                daddr_t lblkno;

                /*
                 * Align to iosize boundary, super-align to page boundary.
                 */
                if (off & iomask) {
                        cnt += off & iomask;
                        off &= ~(u_quad_t)iomask;
                }
                if (off & PAGE_MASK) {
                        cnt += off & PAGE_MASK;
                        off &= ~(u_quad_t)PAGE_MASK;
                }
                lblkno = off / iosize;

                if (vp->v_object &&
                   (vp->v_object->flags & OBJ_MIGHTBEDIRTY)) {
                        VM_OBJECT_WLOCK(vp->v_object);
                        vm_object_page_clean(vp->v_object, off, off + cnt,
                            OBJPC_SYNC);
                        VM_OBJECT_WUNLOCK(vp->v_object);
                }

                bo = &vp->v_bufobj;
                BO_LOCK(bo);
                while (cnt > 0) {
                        struct buf *bp;

                        /*
                         * If we have a buffer and it is marked B_DELWRI we
                         * have to lock and write it.  Otherwise the prior
                         * write is assumed to have already been committed.
                         *
                         * gbincore() can return invalid buffers now so we
                         * have to check that bit as well (though B_DELWRI
                         * should not be set if B_INVAL is set there could be
                         * a race here since we haven't locked the buffer).
                         */
                        if ((bp = gbincore(&vp->v_bufobj, lblkno)) != NULL) {
                                if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_SLEEPFAIL |
                                    LK_INTERLOCK, BO_LOCKPTR(bo)) == ENOLCK) {
                                        BO_LOCK(bo);
                                        continue; /* retry */
                                }
                                if ((bp->b_flags & (B_DELWRI|B_INVAL)) ==
                                    B_DELWRI) {
                                        bremfree(bp);
                                        bp->b_flags &= ~B_ASYNC;
                                        bwrite(bp);
                                        ++nfs_commit_miss;
                                } else
                                        BUF_UNLOCK(bp);
                                BO_LOCK(bo);
                        }
                        ++nfs_commit_blks;
                        if (cnt < iosize)
                                break;
                        cnt -= iosize;
                        ++lblkno;
                }
                BO_UNLOCK(bo);
        }
        NFSEXITCODE(error);
        return (error);
}

/*
 * Statfs vnode op.
 */
int
nfsvno_statfs(struct vnode *vp, struct statfs *sf)
{
        int error;

        error = VFS_STATFS(vp->v_mount, sf);
        if (error == 0) {
                /*
                 * Since NFS handles these values as unsigned on the
                 * wire, there is no way to represent negative values,
                 * so set them to 0. Without this, they will appear
                 * to be very large positive values for clients like
                 * Solaris10.
                 */
                if (sf->f_bavail < 0)
                        sf->f_bavail = 0;
                if (sf->f_ffree < 0)
                        sf->f_ffree = 0;
        }
        NFSEXITCODE(error);
        return (error);
}

/*
 * Do the vnode op stuff for Open. Similar to nfsvno_createsub(), but
 * must handle nfsrv_opencheck() calls after any other access checks.
 */
void
nfsvno_open(struct nfsrv_descript *nd, struct nameidata *ndp,
    nfsquad_t clientid, nfsv4stateid_t *stateidp, struct nfsstate *stp,
    int *exclusive_flagp, struct nfsvattr *nvap, int32_t *cverf, int create,
    NFSACL_T *aclp, nfsattrbit_t *attrbitp, struct ucred *cred, struct thread *p,
    struct nfsexstuff *exp, struct vnode **vpp)
{
        struct vnode *vp = NULL;
        u_quad_t tempsize;
        struct nfsexstuff nes;

        if (ndp->ni_vp == NULL)
                nd->nd_repstat = nfsrv_opencheck(clientid,
                    stateidp, stp, NULL, nd, p, nd->nd_repstat);
        if (!nd->nd_repstat) {
                if (ndp->ni_vp == NULL) {
                        vrele(ndp->ni_startdir);
                        nd->nd_repstat = VOP_CREATE(ndp->ni_dvp,
                            &ndp->ni_vp, &ndp->ni_cnd, &nvap->na_vattr);
                        vput(ndp->ni_dvp);
                        nfsvno_relpathbuf(ndp);
                        if (!nd->nd_repstat) {
                                if (*exclusive_flagp) {
                                        *exclusive_flagp = 0;
                                        NFSVNO_ATTRINIT(nvap);
                                        nvap->na_atime.tv_sec = cverf[0];
                                        nvap->na_atime.tv_nsec = cverf[1];
                                        nd->nd_repstat = VOP_SETATTR(ndp->ni_vp,
                                            &nvap->na_vattr, cred);
                                        if (nd->nd_repstat != 0) {
                                                vput(ndp->ni_vp);
                                                ndp->ni_vp = NULL;
                                                nd->nd_repstat = NFSERR_NOTSUPP;
                                        }
                                } else {
                                        nfsrv_fixattr(nd, ndp->ni_vp, nvap,
                                            aclp, p, attrbitp, exp);
                                }
                        }
                        vp = ndp->ni_vp;
                } else {
                        if (ndp->ni_startdir)
                                vrele(ndp->ni_startdir);
                        nfsvno_relpathbuf(ndp);
                        vp = ndp->ni_vp;
                        if (create == NFSV4OPEN_CREATE) {
                                if (ndp->ni_dvp == vp)
                                        vrele(ndp->ni_dvp);
                                else
                                        vput(ndp->ni_dvp);
                        }
                        if (NFSVNO_ISSETSIZE(nvap) && vp->v_type == VREG) {
                                if (ndp->ni_cnd.cn_flags & RDONLY)
                                        NFSVNO_SETEXRDONLY(&nes);
                                else
                                        NFSVNO_EXINIT(&nes);
                                nd->nd_repstat = nfsvno_accchk(vp, 
                                    VWRITE, cred, &nes, p,
                                    NFSACCCHK_NOOVERRIDE,
                                    NFSACCCHK_VPISLOCKED, NULL);
                                nd->nd_repstat = nfsrv_opencheck(clientid,
                                    stateidp, stp, vp, nd, p, nd->nd_repstat);
                                if (!nd->nd_repstat) {
                                        tempsize = nvap->na_size;
                                        NFSVNO_ATTRINIT(nvap);
                                        nvap->na_size = tempsize;
                                        nd->nd_repstat = VOP_SETATTR(vp,
                                            &nvap->na_vattr, cred);
                                }
                        } else if (vp->v_type == VREG) {
                                nd->nd_repstat = nfsrv_opencheck(clientid,
                                    stateidp, stp, vp, nd, p, nd->nd_repstat);
                        }
                }
        } else {
                if (ndp->ni_cnd.cn_flags & HASBUF)
                        nfsvno_relpathbuf(ndp);
                if (ndp->ni_startdir && create == NFSV4OPEN_CREATE) {
                        vrele(ndp->ni_startdir);
                        if (ndp->ni_dvp == ndp->ni_vp)
                                vrele(ndp->ni_dvp);
                        else
                                vput(ndp->ni_dvp);
                        if (ndp->ni_vp)
                                vput(ndp->ni_vp);
                }
        }
        *vpp = vp;

        NFSEXITCODE2(0, nd);
}

/*
 * Updates the file rev and sets the mtime and ctime
 * to the current clock time, returning the va_filerev and va_Xtime
 * values.
 * Return ESTALE to indicate the vnode is VI_DOOMED.
 */
int
nfsvno_updfilerev(struct vnode *vp, struct nfsvattr *nvap,
    struct ucred *cred, struct thread *p)
{
        struct vattr va;

        VATTR_NULL(&va);
        vfs_timestamp(&va.va_mtime);
        if (NFSVOPISLOCKED(vp) != LK_EXCLUSIVE) {
                NFSVOPLOCK(vp, LK_UPGRADE | LK_RETRY);
                if ((vp->v_iflag & VI_DOOMED) != 0)
                        return (ESTALE);
        }
        (void) VOP_SETATTR(vp, &va, cred);
        (void) nfsvno_getattr(vp, nvap, cred, p, 1);
        return (0);
}

/*
 * Glue routine to nfsv4_fillattr().
 */
int
nfsvno_fillattr(struct nfsrv_descript *nd, struct mount *mp, struct vnode *vp,
    struct nfsvattr *nvap, fhandle_t *fhp, int rderror, nfsattrbit_t *attrbitp,
    struct ucred *cred, struct thread *p, int isdgram, int reterr,
    int supports_nfsv4acls, int at_root, uint64_t mounted_on_fileno)
{
        int error;

        error = nfsv4_fillattr(nd, mp, vp, NULL, &nvap->na_vattr, fhp, rderror,
            attrbitp, cred, p, isdgram, reterr, supports_nfsv4acls, at_root,
            mounted_on_fileno);
        NFSEXITCODE2(0, nd);
        return (error);
}

/* Since the Readdir vnode ops vary, put the entire functions in here. */
/*
 * nfs readdir service
 * - mallocs what it thinks is enough to read
 *      count rounded up to a multiple of DIRBLKSIZ <= NFS_MAXREADDIR
 * - calls VOP_READDIR()
 * - loops around building the reply
 *      if the output generated exceeds count break out of loop
 *      The NFSM_CLGET macro is used here so that the reply will be packed
 *      tightly in mbuf clusters.
 * - it trims out records with d_fileno == 0
 *      this doesn't matter for Unix clients, but they might confuse clients
 *      for other os'.
 * - it trims out records with d_type == DT_WHT
 *      these cannot be seen through NFS (unless we extend the protocol)
 *     The alternate call nfsrvd_readdirplus() does lookups as well.
 * PS: The NFS protocol spec. does not clarify what the "count" byte
 *      argument is a count of.. just name strings and file id's or the
 *      entire reply rpc or ...
 *      I tried just file name and id sizes and it confused the Sun client,
 *      so I am using the full rpc size now. The "paranoia.." comment refers
 *      to including the status longwords that are not a part of the dir.
 *      "entry" structures, but are in the rpc.
 */
int
nfsrvd_readdir(struct nfsrv_descript *nd, int isdgram,
    struct vnode *vp, struct thread *p, struct nfsexstuff *exp)
{
        struct dirent *dp;
        u_int32_t *tl;
        int dirlen;
        char *cpos, *cend, *rbuf;
        struct nfsvattr at;
        int nlen, error = 0, getret = 1;
        int siz, cnt, fullsiz, eofflag, ncookies;
        u_int64_t off, toff, verf;
        u_long *cookies = NULL, *cookiep;
        struct uio io;
        struct iovec iv;
        int is_ufs;

        if (nd->nd_repstat) {
                nfsrv_postopattr(nd, getret, &at);
                goto out;
        }
        if (nd->nd_flag & ND_NFSV2) {
                NFSM_DISSECT(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
                off = fxdr_unsigned(u_quad_t, *tl++);
        } else {
                NFSM_DISSECT(tl, u_int32_t *, 5 * NFSX_UNSIGNED);
                off = fxdr_hyper(tl);
                tl += 2;
                verf = fxdr_hyper(tl);
                tl += 2;
        }
        toff = off;
        cnt = fxdr_unsigned(int, *tl);
        if (cnt > NFS_SRVMAXDATA(nd) || cnt < 0)
                cnt = NFS_SRVMAXDATA(nd);
        siz = ((cnt + DIRBLKSIZ - 1) & ~(DIRBLKSIZ - 1));
        fullsiz = siz;
        if (nd->nd_flag & ND_NFSV3) {
                nd->nd_repstat = getret = nfsvno_getattr(vp, &at, nd->nd_cred,
                    p, 1);
#if 0
                /*
                 * va_filerev is not sufficient as a cookie verifier,
                 * since it is not supposed to change when entries are
                 * removed/added unless that offset cookies returned to
                 * the client are no longer valid.
                 */
                if (!nd->nd_repstat && toff && verf != at.na_filerev)
                        nd->nd_repstat = NFSERR_BAD_COOKIE;
#endif
        }
        if (!nd->nd_repstat && vp->v_type != VDIR)
                nd->nd_repstat = NFSERR_NOTDIR;
        if (nd->nd_repstat == 0 && cnt == 0) {
                if (nd->nd_flag & ND_NFSV2)
                        /* NFSv2 does not have NFSERR_TOOSMALL */
                        nd->nd_repstat = EPERM;
                else
                        nd->nd_repstat = NFSERR_TOOSMALL;
        }
        if (!nd->nd_repstat)
                nd->nd_repstat = nfsvno_accchk(vp, VEXEC,
                    nd->nd_cred, exp, p, NFSACCCHK_NOOVERRIDE,
                    NFSACCCHK_VPISLOCKED, NULL);
        if (nd->nd_repstat) {
                vput(vp);
                if (nd->nd_flag & ND_NFSV3)
                        nfsrv_postopattr(nd, getret, &at);
                goto out;
        }
        is_ufs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "ufs") == 0;
        MALLOC(rbuf, caddr_t, siz, M_TEMP, M_WAITOK);
again:
        eofflag = 0;
        if (cookies) {
                free((caddr_t)cookies, M_TEMP);
                cookies = NULL;
        }

        iv.iov_base = rbuf;
        iv.iov_len = siz;
        io.uio_iov = &iv;
        io.uio_iovcnt = 1;
        io.uio_offset = (off_t)off;
        io.uio_resid = siz;
        io.uio_segflg = UIO_SYSSPACE;
        io.uio_rw = UIO_READ;
        io.uio_td = NULL;
        nd->nd_repstat = VOP_READDIR(vp, &io, nd->nd_cred, &eofflag, &ncookies,
            &cookies);
        off = (u_int64_t)io.uio_offset;
        if (io.uio_resid)
                siz -= io.uio_resid;

        if (!cookies && !nd->nd_repstat)
                nd->nd_repstat = NFSERR_PERM;
        if (nd->nd_flag & ND_NFSV3) {
                getret = nfsvno_getattr(vp, &at, nd->nd_cred, p, 1);
                if (!nd->nd_repstat)
                        nd->nd_repstat = getret;
        }

        /*
         * Handles the failed cases. nd->nd_repstat == 0 past here.
         */
        if (nd->nd_repstat) {
                vput(vp);
                free((caddr_t)rbuf, M_TEMP);
                if (cookies)
                        free((caddr_t)cookies, M_TEMP);
                if (nd->nd_flag & ND_NFSV3)
                        nfsrv_postopattr(nd, getret, &at);
                goto out;
        }
        /*
         * If nothing read, return eof
         * rpc reply
         */
        if (siz == 0) {
                vput(vp);
                if (nd->nd_flag & ND_NFSV2) {
                        NFSM_BUILD(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
                } else {
                        nfsrv_postopattr(nd, getret, &at);
                        NFSM_BUILD(tl, u_int32_t *, 4 * NFSX_UNSIGNED);
                        txdr_hyper(at.na_filerev, tl);
                        tl += 2;
                }
                *tl++ = newnfs_false;
                *tl = newnfs_true;
                FREE((caddr_t)rbuf, M_TEMP);
                FREE((caddr_t)cookies, M_TEMP);
                goto out;
        }

        /*
         * Check for degenerate cases of nothing useful read.
         * If so go try again
         */
        cpos = rbuf;
        cend = rbuf + siz;
        dp = (struct dirent *)cpos;
        cookiep = cookies;

        /*
         * For some reason FreeBSD's ufs_readdir() chooses to back the
         * directory offset up to a block boundary, so it is necessary to
         * skip over the records that precede the requested offset. This
         * requires the assumption that file offset cookies monotonically
         * increase.
         */
        while (cpos < cend && ncookies > 0 &&
            (dp->d_fileno == 0 || dp->d_type == DT_WHT ||
             (is_ufs == 1 && ((u_quad_t)(*cookiep)) <= toff))) {
                cpos += dp->d_reclen;
                dp = (struct dirent *)cpos;
                cookiep++;
                ncookies--;
        }
        if (cpos >= cend || ncookies == 0) {
                siz = fullsiz;
                toff = off;
                goto again;
        }
        vput(vp);

        /*
         * dirlen is the size of the reply, including all XDR and must
         * not exceed cnt. For NFSv2, RFC1094 didn't clearly indicate
         * if the XDR should be included in "count", but to be safe, we do.
         * (Include the two booleans at the end of the reply in dirlen now.)
         */
        if (nd->nd_flag & ND_NFSV3) {
                nfsrv_postopattr(nd, getret, &at);
                NFSM_BUILD(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
                txdr_hyper(at.na_filerev, tl);
                dirlen = NFSX_V3POSTOPATTR + NFSX_VERF + 2 * NFSX_UNSIGNED;
        } else {
                dirlen = 2 * NFSX_UNSIGNED;
        }

        /* Loop through the records and build reply */
        while (cpos < cend && ncookies > 0) {
                nlen = dp->d_namlen;
                if (dp->d_fileno != 0 && dp->d_type != DT_WHT &&
                        nlen <= NFS_MAXNAMLEN) {
                        if (nd->nd_flag & ND_NFSV3)
                                dirlen += (6*NFSX_UNSIGNED + NFSM_RNDUP(nlen));
                        else
                                dirlen += (4*NFSX_UNSIGNED + NFSM_RNDUP(nlen));
                        if (dirlen > cnt) {
                                eofflag = 0;
                                break;
                        }

                        /*
                         * Build the directory record xdr from
                         * the dirent entry.
                         */
                        if (nd->nd_flag & ND_NFSV3) {
                                NFSM_BUILD(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
                                *tl++ = newnfs_true;
                                *tl++ = 0;
                        } else {
                                NFSM_BUILD(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
                                *tl++ = newnfs_true;
                        }
                        *tl = txdr_unsigned(dp->d_fileno);
                        (void) nfsm_strtom(nd, dp->d_name, nlen);
                        if (nd->nd_flag & ND_NFSV3) {
                                NFSM_BUILD(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
                                *tl++ = 0;
                        } else
                                NFSM_BUILD(tl, u_int32_t *, NFSX_UNSIGNED);
                        *tl = txdr_unsigned(*cookiep);
                }
                cpos += dp->d_reclen;
                dp = (struct dirent *)cpos;
                cookiep++;
                ncookies--;
        }
        if (cpos < cend)
                eofflag = 0;
        NFSM_BUILD(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
        *tl++ = newnfs_false;
        if (eofflag)
                *tl = newnfs_true;
        else
                *tl = newnfs_false;
        FREE((caddr_t)rbuf, M_TEMP);
        FREE((caddr_t)cookies, M_TEMP);

out:
        NFSEXITCODE2(0, nd);
        return (0);
nfsmout:
        vput(vp);
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Readdirplus for V3 and Readdir for V4.
 */
int
nfsrvd_readdirplus(struct nfsrv_descript *nd, int isdgram,
    struct vnode *vp, struct thread *p, struct nfsexstuff *exp)
{
        struct dirent *dp;
        u_int32_t *tl;
        int dirlen;
        char *cpos, *cend, *rbuf;
        struct vnode *nvp;
        fhandle_t nfh;
        struct nfsvattr nva, at, *nvap = &nva;
        struct mbuf *mb0, *mb1;
        struct nfsreferral *refp;
        int nlen, r, error = 0, getret = 1, usevget = 1;
        int siz, cnt, fullsiz, eofflag, ncookies, entrycnt;
        caddr_t bpos0, bpos1;
        u_int64_t off, toff, verf;
        u_long *cookies = NULL, *cookiep;
        nfsattrbit_t attrbits, rderrbits, savbits;
        struct uio io;
        struct iovec iv;
        struct componentname cn;
        int at_root, is_ufs, is_zfs, needs_unbusy, supports_nfsv4acls;
        struct mount *mp, *new_mp;
        uint64_t mounted_on_fileno;

        if (nd->nd_repstat) {
                nfsrv_postopattr(nd, getret, &at);
                goto out;
        }
        NFSM_DISSECT(tl, u_int32_t *, 6 * NFSX_UNSIGNED);
        off = fxdr_hyper(tl);
        toff = off;
        tl += 2;
        verf = fxdr_hyper(tl);
        tl += 2;
        siz = fxdr_unsigned(int, *tl++);
        cnt = fxdr_unsigned(int, *tl);

        /*
         * Use the server's maximum data transfer size as the upper bound
         * on reply datalen.
         */
        if (cnt > NFS_SRVMAXDATA(nd) || cnt < 0)
                cnt = NFS_SRVMAXDATA(nd);

        /*
         * siz is a "hint" of how much directory information (name, fileid,
         * cookie) should be in the reply. At least one client "hints" 0,
         * so I set it to cnt for that case. I also round it up to the
         * next multiple of DIRBLKSIZ.
         */
        if (siz <= 0)
                siz = cnt;
        siz = ((siz + DIRBLKSIZ - 1) & ~(DIRBLKSIZ - 1));

        if (nd->nd_flag & ND_NFSV4) {
                error = nfsrv_getattrbits(nd, &attrbits, NULL, NULL);
                if (error)
                        goto nfsmout;
                NFSSET_ATTRBIT(&savbits, &attrbits);
                NFSCLRNOTFILLABLE_ATTRBIT(&attrbits);
                NFSZERO_ATTRBIT(&rderrbits);
                NFSSETBIT_ATTRBIT(&rderrbits, NFSATTRBIT_RDATTRERROR);
        } else {
                NFSZERO_ATTRBIT(&attrbits);
        }
        fullsiz = siz;
        nd->nd_repstat = getret = nfsvno_getattr(vp, &at, nd->nd_cred, p, 1);
        if (!nd->nd_repstat) {
            if (off && verf != at.na_filerev) {
                /*
                 * va_filerev is not sufficient as a cookie verifier,
                 * since it is not supposed to change when entries are
                 * removed/added unless that offset cookies returned to
                 * the client are no longer valid.
                 */
#if 0
                if (nd->nd_flag & ND_NFSV4) {
                        nd->nd_repstat = NFSERR_NOTSAME;
                } else {
                        nd->nd_repstat = NFSERR_BAD_COOKIE;
                }
#endif
            } else if ((nd->nd_flag & ND_NFSV4) && off == 0 && verf != 0) {
                nd->nd_repstat = NFSERR_BAD_COOKIE;
            }
        }
        if (!nd->nd_repstat && vp->v_type != VDIR)
                nd->nd_repstat = NFSERR_NOTDIR;
        if (!nd->nd_repstat && cnt == 0)
                nd->nd_repstat = NFSERR_TOOSMALL;
        if (!nd->nd_repstat)
                nd->nd_repstat = nfsvno_accchk(vp, VEXEC,
                    nd->nd_cred, exp, p, NFSACCCHK_NOOVERRIDE,
                    NFSACCCHK_VPISLOCKED, NULL);
        if (nd->nd_repstat) {
                vput(vp);
                if (nd->nd_flag & ND_NFSV3)
                        nfsrv_postopattr(nd, getret, &at);
                goto out;
        }
        is_ufs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "ufs") == 0;
        is_zfs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "zfs") == 0;

        MALLOC(rbuf, caddr_t, siz, M_TEMP, M_WAITOK);
again:
        eofflag = 0;
        if (cookies) {
                free((caddr_t)cookies, M_TEMP);
                cookies = NULL;
        }

        iv.iov_base = rbuf;
        iv.iov_len = siz;
        io.uio_iov = &iv;
        io.uio_iovcnt = 1;
        io.uio_offset = (off_t)off;
        io.uio_resid = siz;
        io.uio_segflg = UIO_SYSSPACE;
        io.uio_rw = UIO_READ;
        io.uio_td = NULL;
        nd->nd_repstat = VOP_READDIR(vp, &io, nd->nd_cred, &eofflag, &ncookies,
            &cookies);
        off = (u_int64_t)io.uio_offset;
        if (io.uio_resid)
                siz -= io.uio_resid;

        getret = nfsvno_getattr(vp, &at, nd->nd_cred, p, 1);

        if (!cookies && !nd->nd_repstat)
                nd->nd_repstat = NFSERR_PERM;
        if (!nd->nd_repstat)
                nd->nd_repstat = getret;
        if (nd->nd_repstat) {
                vput(vp);
                if (cookies)
                        free((caddr_t)cookies, M_TEMP);
                free((caddr_t)rbuf, M_TEMP);
                if (nd->nd_flag & ND_NFSV3)
                        nfsrv_postopattr(nd, getret, &at);
                goto out;
        }
        /*
         * If nothing read, return eof
         * rpc reply
         */
        if (siz == 0) {
                vput(vp);
                if (nd->nd_flag & ND_NFSV3)
                        nfsrv_postopattr(nd, getret, &at);
                NFSM_BUILD(tl, u_int32_t *, 4 * NFSX_UNSIGNED);
                txdr_hyper(at.na_filerev, tl);
                tl += 2;
                *tl++ = newnfs_false;
                *tl = newnfs_true;
                free((caddr_t)cookies, M_TEMP);
                free((caddr_t)rbuf, M_TEMP);
                goto out;
        }

        /*
         * Check for degenerate cases of nothing useful read.
         * If so go try again
         */
        cpos = rbuf;
        cend = rbuf + siz;
        dp = (struct dirent *)cpos;
        cookiep = cookies;

        /*
         * For some reason FreeBSD's ufs_readdir() chooses to back the
         * directory offset up to a block boundary, so it is necessary to
         * skip over the records that precede the requested offset. This
         * requires the assumption that file offset cookies monotonically
         * increase.
         */
        while (cpos < cend && ncookies > 0 &&
          (dp->d_fileno == 0 || dp->d_type == DT_WHT ||
           (is_ufs == 1 && ((u_quad_t)(*cookiep)) <= toff) ||
           ((nd->nd_flag & ND_NFSV4) &&
            ((dp->d_namlen == 1 && dp->d_name[0] == '.') ||
             (dp->d_namlen==2 && dp->d_name[0]=='.' && dp->d_name[1]=='.'))))) {
                cpos += dp->d_reclen;
                dp = (struct dirent *)cpos;
                cookiep++;
                ncookies--;
        }
        if (cpos >= cend || ncookies == 0) {
                siz = fullsiz;
                toff = off;
                goto again;
        }

        /*
         * Busy the file system so that the mount point won't go away
         * and, as such, VFS_VGET() can be used safely.
         */
        mp = vp->v_mount;
        vfs_ref(mp);
        NFSVOPUNLOCK(vp, 0);
        nd->nd_repstat = vfs_busy(mp, 0);
        vfs_rel(mp);
        if (nd->nd_repstat != 0) {
                vrele(vp);
                free(cookies, M_TEMP);
                free(rbuf, M_TEMP);
                if (nd->nd_flag & ND_NFSV3)
                        nfsrv_postopattr(nd, getret, &at);
                goto out;
        }

        /*
         * Check to see if entries in this directory can be safely acquired
         * via VFS_VGET() or if a switch to VOP_LOOKUP() is required.
         * ZFS snapshot directories need VOP_LOOKUP(), so that any
         * automount of the snapshot directory that is required will
         * be done.
         * This needs to be done here for NFSv4, since NFSv4 never does
         * a VFS_VGET() for "." or "..".
         */
        if (is_zfs == 1) {
                r = VFS_VGET(mp, at.na_fileid, LK_SHARED, &nvp);
                if (r == EOPNOTSUPP) {
                        usevget = 0;
                        cn.cn_nameiop = LOOKUP;
                        cn.cn_lkflags = LK_SHARED | LK_RETRY;
                        cn.cn_cred = nd->nd_cred;
                        cn.cn_thread = p;
                } else if (r == 0)
                        vput(nvp);
        }

        /*
         * Save this position, in case there is an error before one entry
         * is created.
         */
        mb0 = nd->nd_mb;
        bpos0 = nd->nd_bpos;

        /*
         * Fill in the first part of the reply.
         * dirlen is the reply length in bytes and cannot exceed cnt.
         * (Include the two booleans at the end of the reply in dirlen now,
         *  so we recognize when we have exceeded cnt.)
         */
        if (nd->nd_flag & ND_NFSV3) {
                dirlen = NFSX_V3POSTOPATTR + NFSX_VERF + 2 * NFSX_UNSIGNED;
                nfsrv_postopattr(nd, getret, &at);
        } else {
                dirlen = NFSX_VERF + 2 * NFSX_UNSIGNED;
        }
        NFSM_BUILD(tl, u_int32_t *, NFSX_VERF);
        txdr_hyper(at.na_filerev, tl);

        /*
         * Save this position, in case there is an empty reply needed.
         */
        mb1 = nd->nd_mb;
        bpos1 = nd->nd_bpos;

        /* Loop through the records and build reply */
        entrycnt = 0;
        while (cpos < cend && ncookies > 0 && dirlen < cnt) {
                nlen = dp->d_namlen;
                if (dp->d_fileno != 0 && dp->d_type != DT_WHT &&
                    nlen <= NFS_MAXNAMLEN &&
                    ((nd->nd_flag & ND_NFSV3) || nlen > 2 ||
                     (nlen==2 && (dp->d_name[0]!='.' || dp->d_name[1]!='.'))
                      || (nlen == 1 && dp->d_name[0] != '.'))) {
                        /*
                         * Save the current position in the reply, in case
                         * this entry exceeds cnt.
                         */
                        mb1 = nd->nd_mb;
                        bpos1 = nd->nd_bpos;
        
                        /*
                         * For readdir_and_lookup get the vnode using
                         * the file number.
                         */
                        nvp = NULL;
                        refp = NULL;
                        r = 0;
                        at_root = 0;
                        needs_unbusy = 0;
                        new_mp = mp;
                        mounted_on_fileno = (uint64_t)dp->d_fileno;
                        if ((nd->nd_flag & ND_NFSV3) ||
                            NFSNONZERO_ATTRBIT(&savbits)) {
                                if (nd->nd_flag & ND_NFSV4)
                                        refp = nfsv4root_getreferral(NULL,
                                            vp, dp->d_fileno);
                                if (refp == NULL) {
                                        if (usevget)
                                                r = VFS_VGET(mp, dp->d_fileno,
                                                    LK_SHARED, &nvp);
                                        else
                                                r = EOPNOTSUPP;
                                        if (r == EOPNOTSUPP) {
                                                if (usevget) {
                                                        usevget = 0;
                                                        cn.cn_nameiop = LOOKUP;
                                                        cn.cn_lkflags =
                                                            LK_SHARED |
                                                            LK_RETRY;
                                                        cn.cn_cred =
                                                            nd->nd_cred;
                                                        cn.cn_thread = p;
                                                }
                                                cn.cn_nameptr = dp->d_name;
                                                cn.cn_namelen = nlen;
                                                cn.cn_flags = ISLASTCN |
                                                    NOFOLLOW | LOCKLEAF;
                                                if (nlen == 2 &&
                                                    dp->d_name[0] == '.' &&
                                                    dp->d_name[1] == '.')
                                                        cn.cn_flags |=
                                                            ISDOTDOT;
                                                if (NFSVOPLOCK(vp, LK_SHARED)
                                                    != 0) {
                                                        nd->nd_repstat = EPERM;
                                                        break;
                                                }
                                                if ((vp->v_vflag & VV_ROOT) != 0
                                                    && (cn.cn_flags & ISDOTDOT)
                                                    != 0) {
                                                        vref(vp);
                                                        nvp = vp;
                                                        r = 0;
                                                } else {
                                                        r = VOP_LOOKUP(vp, &nvp,
                                                            &cn);
                                                        if (vp != nvp)
                                                                NFSVOPUNLOCK(vp,
                                                                    0);
                                                }
                                        }

                                        /*
                                         * For NFSv4, check to see if nvp is
                                         * a mount point and get the mount
                                         * point vnode, as required.
                                         */
                                        if (r == 0 &&
                                            nfsrv_enable_crossmntpt != 0 &&
                                            (nd->nd_flag & ND_NFSV4) != 0 &&
                                            nvp->v_type == VDIR &&
                                            nvp->v_mountedhere != NULL) {
                                                new_mp = nvp->v_mountedhere;
                                                r = vfs_busy(new_mp, 0);
                                                vput(nvp);
                                                nvp = NULL;
                                                if (r == 0) {
                                                        r = VFS_ROOT(new_mp,
                                                            LK_SHARED, &nvp);
                                                        needs_unbusy = 1;
                                                        if (r == 0)
                                                                at_root = 1;
                                                }
                                        }
                                }
                                if (!r) {
                                    if (refp == NULL &&
                                        ((nd->nd_flag & ND_NFSV3) ||
                                         NFSNONZERO_ATTRBIT(&attrbits))) {
                                        r = nfsvno_getfh(nvp, &nfh, p);
                                        if (!r)
                                            r = nfsvno_getattr(nvp, nvap,
                                                nd->nd_cred, p, 1);
                                        if (r == 0 && is_zfs == 1 &&
                                            nfsrv_enable_crossmntpt != 0 &&
                                            (nd->nd_flag & ND_NFSV4) != 0 &&
                                            nvp->v_type == VDIR &&
                                            vp->v_mount != nvp->v_mount) {
                                            /*
                                             * For a ZFS snapshot, there is a
                                             * pseudo mount that does not set
                                             * v_mountedhere, so it needs to
                                             * be detected via a different
                                             * mount structure.
                                             */
                                            at_root = 1;
                                            if (new_mp == mp)
                                                new_mp = nvp->v_mount;
                                        }
                                    }
                                } else {
                                    nvp = NULL;
                                }
                                if (r) {
                                        if (!NFSISSET_ATTRBIT(&attrbits,
                                            NFSATTRBIT_RDATTRERROR)) {
                                                if (nvp != NULL)
                                                        vput(nvp);
                                                if (needs_unbusy != 0)
                                                        vfs_unbusy(new_mp);
                                                nd->nd_repstat = r;
                                                break;
                                        }
                                }
                        }

                        /*
                         * Build the directory record xdr
                         */
                        if (nd->nd_flag & ND_NFSV3) {
                                NFSM_BUILD(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
                                *tl++ = newnfs_true;
                                *tl++ = 0;
                                *tl = txdr_unsigned(dp->d_fileno);
                                dirlen += nfsm_strtom(nd, dp->d_name, nlen);
                                NFSM_BUILD(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
                                *tl++ = 0;
                                *tl = txdr_unsigned(*cookiep);
                                nfsrv_postopattr(nd, 0, nvap);
                                dirlen += nfsm_fhtom(nd,(u_int8_t *)&nfh,0,1);
                                dirlen += (5*NFSX_UNSIGNED+NFSX_V3POSTOPATTR);
                                if (nvp != NULL)
                                        vput(nvp);
                        } else {
                                NFSM_BUILD(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
                                *tl++ = newnfs_true;
                                *tl++ = 0;
                                *tl = txdr_unsigned(*cookiep);
                                dirlen += nfsm_strtom(nd, dp->d_name, nlen);
                                if (nvp != NULL) {
                                        supports_nfsv4acls =
                                            nfs_supportsnfsv4acls(nvp);
                                        NFSVOPUNLOCK(nvp, 0);
                                } else
                                        supports_nfsv4acls = 0;
                                if (refp != NULL) {
                                        dirlen += nfsrv_putreferralattr(nd,
                                            &savbits, refp, 0,
                                            &nd->nd_repstat);
                                        if (nd->nd_repstat) {
                                                if (nvp != NULL)
                                                        vrele(nvp);
                                                if (needs_unbusy != 0)
                                                        vfs_unbusy(new_mp);
                                                break;
                                        }
                                } else if (r) {
                                        dirlen += nfsvno_fillattr(nd, new_mp,
                                            nvp, nvap, &nfh, r, &rderrbits,
                                            nd->nd_cred, p, isdgram, 0,
                                            supports_nfsv4acls, at_root,
                                            mounted_on_fileno);
                                } else {
                                        dirlen += nfsvno_fillattr(nd, new_mp,
                                            nvp, nvap, &nfh, r, &attrbits,
                                            nd->nd_cred, p, isdgram, 0,
                                            supports_nfsv4acls, at_root,
                                            mounted_on_fileno);
                                }
                                if (nvp != NULL)
                                        vrele(nvp);
                                dirlen += (3 * NFSX_UNSIGNED);
                        }
                        if (needs_unbusy != 0)
                                vfs_unbusy(new_mp);
                        if (dirlen <= cnt)
                                entrycnt++;
                }
                cpos += dp->d_reclen;
                dp = (struct dirent *)cpos;
                cookiep++;
                ncookies--;
        }
        vrele(vp);
        vfs_unbusy(mp);

        /*
         * If dirlen > cnt, we must strip off the last entry. If that
         * results in an empty reply, report NFSERR_TOOSMALL.
         */
        if (dirlen > cnt || nd->nd_repstat) {
                if (!nd->nd_repstat && entrycnt == 0)
                        nd->nd_repstat = NFSERR_TOOSMALL;
                if (nd->nd_repstat) {
                        newnfs_trimtrailing(nd, mb0, bpos0);
                        if (nd->nd_flag & ND_NFSV3)
                                nfsrv_postopattr(nd, getret, &at);
                } else
                        newnfs_trimtrailing(nd, mb1, bpos1);
                eofflag = 0;
        } else if (cpos < cend)
                eofflag = 0;
        if (!nd->nd_repstat) {
                NFSM_BUILD(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
                *tl++ = newnfs_false;
                if (eofflag)
                        *tl = newnfs_true;
                else
                        *tl = newnfs_false;
        }
        FREE((caddr_t)cookies, M_TEMP);
        FREE((caddr_t)rbuf, M_TEMP);

out:
        NFSEXITCODE2(0, nd);
        return (0);
nfsmout:
        vput(vp);
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Get the settable attributes out of the mbuf list.
 * (Return 0 or EBADRPC)
 */
int
nfsrv_sattr(struct nfsrv_descript *nd, vnode_t vp, struct nfsvattr *nvap,
    nfsattrbit_t *attrbitp, NFSACL_T *aclp, struct thread *p)
{
        u_int32_t *tl;
        struct nfsv2_sattr *sp;
        int error = 0, toclient = 0;

        switch (nd->nd_flag & (ND_NFSV2 | ND_NFSV3 | ND_NFSV4)) {
        case ND_NFSV2:
                NFSM_DISSECT(sp, struct nfsv2_sattr *, NFSX_V2SATTR);
                /*
                 * Some old clients didn't fill in the high order 16bits.
                 * --> check the low order 2 bytes for 0xffff
                 */
                if ((fxdr_unsigned(int, sp->sa_mode) & 0xffff) != 0xffff)
                        nvap->na_mode = nfstov_mode(sp->sa_mode);
                if (sp->sa_uid != newnfs_xdrneg1)
                        nvap->na_uid = fxdr_unsigned(uid_t, sp->sa_uid);
                if (sp->sa_gid != newnfs_xdrneg1)
                        nvap->na_gid = fxdr_unsigned(gid_t, sp->sa_gid);
                if (sp->sa_size != newnfs_xdrneg1)
                        nvap->na_size = fxdr_unsigned(u_quad_t, sp->sa_size);
                if (sp->sa_atime.nfsv2_sec != newnfs_xdrneg1) {
#ifdef notyet
                        fxdr_nfsv2time(&sp->sa_atime, &nvap->na_atime);
#else
                        nvap->na_atime.tv_sec =
                                fxdr_unsigned(u_int32_t,sp->sa_atime.nfsv2_sec);
                        nvap->na_atime.tv_nsec = 0;
#endif
                }
                if (sp->sa_mtime.nfsv2_sec != newnfs_xdrneg1)
                        fxdr_nfsv2time(&sp->sa_mtime, &nvap->na_mtime);
                break;
        case ND_NFSV3:
                NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                if (*tl == newnfs_true) {
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                        nvap->na_mode = nfstov_mode(*tl);
                }
                NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                if (*tl == newnfs_true) {
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                        nvap->na_uid = fxdr_unsigned(uid_t, *tl);
                }
                NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                if (*tl == newnfs_true) {
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                        nvap->na_gid = fxdr_unsigned(gid_t, *tl);
                }
                NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                if (*tl == newnfs_true) {
                        NFSM_DISSECT(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
                        nvap->na_size = fxdr_hyper(tl);
                }
                NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                switch (fxdr_unsigned(int, *tl)) {
                case NFSV3SATTRTIME_TOCLIENT:
                        NFSM_DISSECT(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
                        fxdr_nfsv3time(tl, &nvap->na_atime);
                        toclient = 1;
                        break;
                case NFSV3SATTRTIME_TOSERVER:
                        vfs_timestamp(&nvap->na_atime);
                        nvap->na_vaflags |= VA_UTIMES_NULL;
                        break;
                }
                NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                switch (fxdr_unsigned(int, *tl)) {
                case NFSV3SATTRTIME_TOCLIENT:
                        NFSM_DISSECT(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
                        fxdr_nfsv3time(tl, &nvap->na_mtime);
                        nvap->na_vaflags &= ~VA_UTIMES_NULL;
                        break;
                case NFSV3SATTRTIME_TOSERVER:
                        vfs_timestamp(&nvap->na_mtime);
                        if (!toclient)
                                nvap->na_vaflags |= VA_UTIMES_NULL;
                        break;
                }
                break;
        case ND_NFSV4:
                error = nfsv4_sattr(nd, vp, nvap, attrbitp, aclp, p);
        }
nfsmout:
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Handle the setable attributes for V4.
 * Returns NFSERR_BADXDR if it can't be parsed, 0 otherwise.
 */
int
nfsv4_sattr(struct nfsrv_descript *nd, vnode_t vp, struct nfsvattr *nvap,
    nfsattrbit_t *attrbitp, NFSACL_T *aclp, struct thread *p)
{
        u_int32_t *tl;
        int attrsum = 0;
        int i, j;
        int error, attrsize, bitpos, aclsize, aceerr, retnotsup = 0;
        int toclient = 0;
        u_char *cp, namestr[NFSV4_SMALLSTR + 1];
        uid_t uid;
        gid_t gid;

        error = nfsrv_getattrbits(nd, attrbitp, NULL, &retnotsup);
        if (error)
                goto nfsmout;
        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
        attrsize = fxdr_unsigned(int, *tl);

        /*
         * Loop around getting the setable attributes. If an unsupported
         * one is found, set nd_repstat == NFSERR_ATTRNOTSUPP and return.
         */
        if (retnotsup) {
                nd->nd_repstat = NFSERR_ATTRNOTSUPP;
                bitpos = NFSATTRBIT_MAX;
        } else {
                bitpos = 0;
        }
        for (; bitpos < NFSATTRBIT_MAX; bitpos++) {
            if (attrsum > attrsize) {
                error = NFSERR_BADXDR;
                goto nfsmout;
            }
            if (NFSISSET_ATTRBIT(attrbitp, bitpos))
                switch (bitpos) {
                case NFSATTRBIT_SIZE:
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_HYPER);
                     if (vp != NULL && vp->v_type != VREG) {
                            error = (vp->v_type == VDIR) ? NFSERR_ISDIR :
                                NFSERR_INVAL;
                            goto nfsmout;
                        }
                        nvap->na_size = fxdr_hyper(tl);
                        attrsum += NFSX_HYPER;
                        break;
                case NFSATTRBIT_ACL:
                        error = nfsrv_dissectacl(nd, aclp, &aceerr, &aclsize,
                            p);
                        if (error)
                                goto nfsmout;
                        if (aceerr && !nd->nd_repstat)
                                nd->nd_repstat = aceerr;
                        attrsum += aclsize;
                        break;
                case NFSATTRBIT_ARCHIVE:
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                        if (!nd->nd_repstat)
                                nd->nd_repstat = NFSERR_ATTRNOTSUPP;
                        attrsum += NFSX_UNSIGNED;
                        break;
                case NFSATTRBIT_HIDDEN:
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                        if (!nd->nd_repstat)
                                nd->nd_repstat = NFSERR_ATTRNOTSUPP;
                        attrsum += NFSX_UNSIGNED;
                        break;
                case NFSATTRBIT_MIMETYPE:
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                        i = fxdr_unsigned(int, *tl);
                        error = nfsm_advance(nd, NFSM_RNDUP(i), -1);
                        if (error)
                                goto nfsmout;
                        if (!nd->nd_repstat)
                                nd->nd_repstat = NFSERR_ATTRNOTSUPP;
                        attrsum += (NFSX_UNSIGNED + NFSM_RNDUP(i));
                        break;
                case NFSATTRBIT_MODE:
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                        nvap->na_mode = nfstov_mode(*tl);
                        attrsum += NFSX_UNSIGNED;
                        break;
                case NFSATTRBIT_OWNER:
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                        j = fxdr_unsigned(int, *tl);
                        if (j < 0) {
                                error = NFSERR_BADXDR;
                                goto nfsmout;
                        }
                        if (j > NFSV4_SMALLSTR)
                                cp = malloc(j + 1, M_NFSSTRING, M_WAITOK);
                        else
                                cp = namestr;
                        error = nfsrv_mtostr(nd, cp, j);
                        if (error) {
                                if (j > NFSV4_SMALLSTR)
                                        free(cp, M_NFSSTRING);
                                goto nfsmout;
                        }
                        if (!nd->nd_repstat) {
                                nd->nd_repstat = nfsv4_strtouid(nd, cp, j, &uid,
                                    p);
                                if (!nd->nd_repstat)
                                        nvap->na_uid = uid;
                        }
                        if (j > NFSV4_SMALLSTR)
                                free(cp, M_NFSSTRING);
                        attrsum += (NFSX_UNSIGNED + NFSM_RNDUP(j));
                        break;
                case NFSATTRBIT_OWNERGROUP:
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                        j = fxdr_unsigned(int, *tl);
                        if (j < 0) {
                                error = NFSERR_BADXDR;
                                goto nfsmout;
                        }
                        if (j > NFSV4_SMALLSTR)
                                cp = malloc(j + 1, M_NFSSTRING, M_WAITOK);
                        else
                                cp = namestr;
                        error = nfsrv_mtostr(nd, cp, j);
                        if (error) {
                                if (j > NFSV4_SMALLSTR)
                                        free(cp, M_NFSSTRING);
                                goto nfsmout;
                        }
                        if (!nd->nd_repstat) {
                                nd->nd_repstat = nfsv4_strtogid(nd, cp, j, &gid,
                                    p);
                                if (!nd->nd_repstat)
                                        nvap->na_gid = gid;
                        }
                        if (j > NFSV4_SMALLSTR)
                                free(cp, M_NFSSTRING);
                        attrsum += (NFSX_UNSIGNED + NFSM_RNDUP(j));
                        break;
                case NFSATTRBIT_SYSTEM:
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                        if (!nd->nd_repstat)
                                nd->nd_repstat = NFSERR_ATTRNOTSUPP;
                        attrsum += NFSX_UNSIGNED;
                        break;
                case NFSATTRBIT_TIMEACCESSSET:
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                        attrsum += NFSX_UNSIGNED;
                        if (fxdr_unsigned(int, *tl)==NFSV4SATTRTIME_TOCLIENT) {
                            NFSM_DISSECT(tl, u_int32_t *, NFSX_V4TIME);
                            fxdr_nfsv4time(tl, &nvap->na_atime);
                            toclient = 1;
                            attrsum += NFSX_V4TIME;
                        } else {
                            vfs_timestamp(&nvap->na_atime);
                            nvap->na_vaflags |= VA_UTIMES_NULL;
                        }
                        break;
                case NFSATTRBIT_TIMEBACKUP:
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_V4TIME);
                        if (!nd->nd_repstat)
                                nd->nd_repstat = NFSERR_ATTRNOTSUPP;
                        attrsum += NFSX_V4TIME;
                        break;
                case NFSATTRBIT_TIMECREATE:
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_V4TIME);
                        if (!nd->nd_repstat)
                                nd->nd_repstat = NFSERR_ATTRNOTSUPP;
                        attrsum += NFSX_V4TIME;
                        break;
                case NFSATTRBIT_TIMEMODIFYSET:
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                        attrsum += NFSX_UNSIGNED;
                        if (fxdr_unsigned(int, *tl)==NFSV4SATTRTIME_TOCLIENT) {
                            NFSM_DISSECT(tl, u_int32_t *, NFSX_V4TIME);
                            fxdr_nfsv4time(tl, &nvap->na_mtime);
                            nvap->na_vaflags &= ~VA_UTIMES_NULL;
                            attrsum += NFSX_V4TIME;
                        } else {
                            vfs_timestamp(&nvap->na_mtime);
                            if (!toclient)
                                nvap->na_vaflags |= VA_UTIMES_NULL;
                        }
                        break;
                default:
                        nd->nd_repstat = NFSERR_ATTRNOTSUPP;
                        /*
                         * set bitpos so we drop out of the loop.
                         */
                        bitpos = NFSATTRBIT_MAX;
                        break;
                }
        }

        /*
         * some clients pad the attrlist, so we need to skip over the
         * padding.
         */
        if (attrsum > attrsize) {
                error = NFSERR_BADXDR;
        } else {
                attrsize = NFSM_RNDUP(attrsize);
                if (attrsum < attrsize)
                        error = nfsm_advance(nd, attrsize - attrsum, -1);
        }
nfsmout:
        NFSEXITCODE2(error, nd);
        return (error);
}

/*
 * Check/setup export credentials.
 */
int
nfsd_excred(struct nfsrv_descript *nd, struct nfsexstuff *exp,
    struct ucred *credanon)
{
        int error = 0;

        /*
         * Check/setup credentials.
         */
        if (nd->nd_flag & ND_GSS)
                exp->nes_exflag &= ~MNT_EXPORTANON;

        /*
         * Check to see if the operation is allowed for this security flavor.
         * RFC2623 suggests that the NFSv3 Fsinfo RPC be allowed to
         * AUTH_NONE or AUTH_SYS for file systems requiring RPCSEC_GSS.
         * Also, allow Secinfo, so that it can acquire the correct flavor(s).
         */
        if (nfsvno_testexp(nd, exp) &&
            nd->nd_procnum != NFSV4OP_SECINFO &&
            nd->nd_procnum != NFSPROC_FSINFO) {
                if (nd->nd_flag & ND_NFSV4)
                        error = NFSERR_WRONGSEC;
                else
                        error = (NFSERR_AUTHERR | AUTH_TOOWEAK);
                goto out;
        }

        /*
         * Check to see if the file system is exported V4 only.
         */
        if (NFSVNO_EXV4ONLY(exp) && !(nd->nd_flag & ND_NFSV4)) {
                error = NFSERR_PROGNOTV4;
                goto out;
        }

        /*
         * Now, map the user credentials.
         * (Note that ND_AUTHNONE will only be set for an NFSv3
         *  Fsinfo RPC. If set for anything else, this code might need
         *  to change.)
         */
        if (NFSVNO_EXPORTED(exp)) {
                if (((nd->nd_flag & ND_GSS) == 0 && nd->nd_cred->cr_uid == 0) ||
                     NFSVNO_EXPORTANON(exp) ||
                     (nd->nd_flag & ND_AUTHNONE) != 0) {
                        nd->nd_cred->cr_uid = credanon->cr_uid;
                        nd->nd_cred->cr_gid = credanon->cr_gid;
                        crsetgroups(nd->nd_cred, credanon->cr_ngroups,
                            credanon->cr_groups);
                } else if ((nd->nd_flag & ND_GSS) == 0) {
                        /*
                         * If using AUTH_SYS, call nfsrv_getgrpscred() to see
                         * if there is a replacement credential with a group
                         * list set up by "nfsuserd -manage-gids".
                         * If there is no replacement, nfsrv_getgrpscred()
                         * simply returns its argument.
                         */
                        nd->nd_cred = nfsrv_getgrpscred(nd->nd_cred);
                }
        }

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

/*
 * Check exports.
 */
int
nfsvno_checkexp(struct mount *mp, struct sockaddr *nam, struct nfsexstuff *exp,
    struct ucred **credp)
{
        int i, error, *secflavors;

        error = VFS_CHECKEXP(mp, nam, &exp->nes_exflag, credp,
            &exp->nes_numsecflavor, &secflavors);
        if (error) {
                if (nfs_rootfhset) {
                        exp->nes_exflag = 0;
                        exp->nes_numsecflavor = 0;
                        error = 0;
                }
        } else {
                /* Copy the security flavors. */
                for (i = 0; i < exp->nes_numsecflavor; i++)
                        exp->nes_secflavors[i] = secflavors[i];
        }
        NFSEXITCODE(error);
        return (error);
}

/*
 * Get a vnode for a file handle and export stuff.
 */
int
nfsvno_fhtovp(struct mount *mp, fhandle_t *fhp, struct sockaddr *nam,
    int lktype, struct vnode **vpp, struct nfsexstuff *exp,
    struct ucred **credp)
{
        int i, error, *secflavors;

        *credp = NULL;
        exp->nes_numsecflavor = 0;
        error = VFS_FHTOVP(mp, &fhp->fh_fid, lktype, vpp);
        if (error != 0)
                /* Make sure the server replies ESTALE to the client. */
                error = ESTALE;
        if (nam && !error) {
                error = VFS_CHECKEXP(mp, nam, &exp->nes_exflag, credp,
                    &exp->nes_numsecflavor, &secflavors);
                if (error) {
                        if (nfs_rootfhset) {
                                exp->nes_exflag = 0;
                                exp->nes_numsecflavor = 0;
                                error = 0;
                        } else {
                                vput(*vpp);
                        }
                } else {
                        /* Copy the security flavors. */
                        for (i = 0; i < exp->nes_numsecflavor; i++)
                                exp->nes_secflavors[i] = secflavors[i];
                }
        }
        NFSEXITCODE(error);
        return (error);
}

/*
 * nfsd_fhtovp() - convert a fh to a vnode ptr
 *      - look up fsid in mount list (if not found ret error)
 *      - get vp and export rights by calling nfsvno_fhtovp()
 *      - if cred->cr_uid == 0 or MNT_EXPORTANON set it to credanon
 *        for AUTH_SYS
 *      - if mpp != NULL, return the mount point so that it can
 *        be used for vn_finished_write() by the caller
 */
void
nfsd_fhtovp(struct nfsrv_descript *nd, struct nfsrvfh *nfp, int lktype,
    struct vnode **vpp, struct nfsexstuff *exp,
    struct mount **mpp, int startwrite, struct thread *p)
{
        struct mount *mp;
        struct ucred *credanon;
        fhandle_t *fhp;

        fhp = (fhandle_t *)nfp->nfsrvfh_data;
        /*
         * Check for the special case of the nfsv4root_fh.
         */
        mp = vfs_busyfs(&fhp->fh_fsid);
        if (mpp != NULL)
                *mpp = mp;
        if (mp == NULL) {
                *vpp = NULL;
                nd->nd_repstat = ESTALE;
                goto out;
        }

        if (startwrite) {
                vn_start_write(NULL, mpp, V_WAIT);
                if (lktype == LK_SHARED && !(MNT_SHARED_WRITES(mp)))
                        lktype = LK_EXCLUSIVE;
        }
        nd->nd_repstat = nfsvno_fhtovp(mp, fhp, nd->nd_nam, lktype, vpp, exp,
            &credanon);
        vfs_unbusy(mp);

        /*
         * For NFSv4 without a pseudo root fs, unexported file handles
         * can be returned, so that Lookup works everywhere.
         */
        if (!nd->nd_repstat && exp->nes_exflag == 0 &&
            !(nd->nd_flag & ND_NFSV4)) {
                vput(*vpp);
                nd->nd_repstat = EACCES;
        }

        /*
         * Personally, I've never seen any point in requiring a
         * reserved port#, since only in the rare case where the
         * clients are all boxes with secure system privileges,
         * does it provide any enhanced security, but... some people
         * believe it to be useful and keep putting this code back in.
         * (There is also some "security checker" out there that
         *  complains if the nfs server doesn't enforce this.)
         * However, note the following:
         * RFC3530 (NFSv4) specifies that a reserved port# not be
         *      required.
         * RFC2623 recommends that, if a reserved port# is checked for,
         *      that there be a way to turn that off--> ifdef'd.
         */
#ifdef NFS_REQRSVPORT
        if (!nd->nd_repstat) {
                struct sockaddr_in *saddr;
                struct sockaddr_in6 *saddr6;

                saddr = NFSSOCKADDR(nd->nd_nam, struct sockaddr_in *);
                saddr6 = NFSSOCKADDR(nd->nd_nam, struct sockaddr_in6 *);
                if (!(nd->nd_flag & ND_NFSV4) &&
                    ((saddr->sin_family == AF_INET &&
                      ntohs(saddr->sin_port) >= IPPORT_RESERVED) ||
                     (saddr6->sin6_family == AF_INET6 &&
                      ntohs(saddr6->sin6_port) >= IPPORT_RESERVED))) {
                        vput(*vpp);
                        nd->nd_repstat = (NFSERR_AUTHERR | AUTH_TOOWEAK);
                }
        }
#endif  /* NFS_REQRSVPORT */

        /*
         * Check/setup credentials.
         */
        if (!nd->nd_repstat) {
                nd->nd_saveduid = nd->nd_cred->cr_uid;
                nd->nd_repstat = nfsd_excred(nd, exp, credanon);
                if (nd->nd_repstat)
                        vput(*vpp);
        }
        if (credanon != NULL)
                crfree(credanon);
        if (nd->nd_repstat) {
                if (startwrite)
                        vn_finished_write(mp);
                *vpp = NULL;
                if (mpp != NULL)
                        *mpp = NULL;
        }

out:
        NFSEXITCODE2(0, nd);
}

/*
 * glue for fp.
 */
static int
fp_getfvp(struct thread *p, int fd, struct file **fpp, struct vnode **vpp)
{
        struct filedesc *fdp;
        struct file *fp;
        int error = 0;

        fdp = p->td_proc->p_fd;
        if (fd < 0 || fd >= fdp->fd_nfiles ||
            (fp = fdp->fd_ofiles[fd].fde_file) == NULL) {
                error = EBADF;
                goto out;
        }
        *fpp = fp;

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

/*
 * Called from nfssvc() to update the exports list. Just call
 * vfs_export(). This has to be done, since the v4 root fake fs isn't
 * in the mount list.
 */
int
nfsrv_v4rootexport(void *argp, struct ucred *cred, struct thread *p)
{
        struct nfsex_args *nfsexargp = (struct nfsex_args *)argp;
        int error = 0;
        struct nameidata nd;
        fhandle_t fh;

        error = vfs_export(&nfsv4root_mnt, &nfsexargp->export);
        if ((nfsexargp->export.ex_flags & MNT_DELEXPORT) != 0)
                nfs_rootfhset = 0;
        else if (error == 0) {
                if (nfsexargp->fspec == NULL) {
                        error = EPERM;
                        goto out;
                }
                /*
                 * If fspec != NULL, this is the v4root path.
                 */
                NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE,
                    nfsexargp->fspec, p);
                if ((error = namei(&nd)) != 0)
                        goto out;
                error = nfsvno_getfh(nd.ni_vp, &fh, p);
                vrele(nd.ni_vp);
                if (!error) {
                        nfs_rootfh.nfsrvfh_len = NFSX_MYFH;
                        NFSBCOPY((caddr_t)&fh,
                            nfs_rootfh.nfsrvfh_data,
                            sizeof (fhandle_t));
                        nfs_rootfhset = 1;
                }
        }

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

/*
 * This function needs to test to see if the system is near its limit
 * for memory allocation via malloc() or mget() and return True iff
 * either of these resources are near their limit.
 * XXX (For now, this is just a stub.)
 */
int nfsrv_testmalloclimit = 0;
int
nfsrv_mallocmget_limit(void)
{
        static int printmesg = 0;
        static int testval = 1;

        if (nfsrv_testmalloclimit && (testval++ % 1000) == 0) {
                if ((printmesg++ % 100) == 0)
                        printf("nfsd: malloc/mget near limit\n");
                return (1);
        }
        return (0);
}

/*
 * BSD specific initialization of a mount point.
 */
void
nfsd_mntinit(void)
{
        static int inited = 0;

        if (inited)
                return;
        inited = 1;
        nfsv4root_mnt.mnt_flag = (MNT_RDONLY | MNT_EXPORTED);
        TAILQ_INIT(&nfsv4root_mnt.mnt_nvnodelist);
        TAILQ_INIT(&nfsv4root_mnt.mnt_activevnodelist);
        nfsv4root_mnt.mnt_export = NULL;
        TAILQ_INIT(&nfsv4root_opt);
        TAILQ_INIT(&nfsv4root_newopt);
        nfsv4root_mnt.mnt_opt = &nfsv4root_opt;
        nfsv4root_mnt.mnt_optnew = &nfsv4root_newopt;
        nfsv4root_mnt.mnt_nvnodelistsize = 0;
        nfsv4root_mnt.mnt_activevnodelistsize = 0;
}

/*
 * Get a vnode for a file handle, without checking exports, etc.
 */
struct vnode *
nfsvno_getvp(fhandle_t *fhp)
{
        struct mount *mp;
        struct vnode *vp;
        int error;

        mp = vfs_busyfs(&fhp->fh_fsid);
        if (mp == NULL)
                return (NULL);
        error = VFS_FHTOVP(mp, &fhp->fh_fid, LK_EXCLUSIVE, &vp);
        vfs_unbusy(mp);
        if (error)
                return (NULL);
        return (vp);
}

/*
 * Do a local VOP_ADVLOCK().
 */
int
nfsvno_advlock(struct vnode *vp, int ftype, u_int64_t first,
    u_int64_t end, struct thread *td)
{
        int error = 0;
        struct flock fl;
        u_int64_t tlen;

        if (nfsrv_dolocallocks == 0)
                goto out;
        ASSERT_VOP_UNLOCKED(vp, "nfsvno_advlock: vp locked");

        fl.l_whence = SEEK_SET;
        fl.l_type = ftype;
        fl.l_start = (off_t)first;
        if (end == NFS64BITSSET) {
                fl.l_len = 0;
        } else {
                tlen = end - first;
                fl.l_len = (off_t)tlen;
        }
        /*
         * For FreeBSD8, the l_pid and l_sysid must be set to the same
         * values for all calls, so that all locks will be held by the
         * nfsd server. (The nfsd server handles conflicts between the
         * various clients.)
         * Since an NFSv4 lockowner is a ClientID plus an array of up to 1024
         * bytes, so it can't be put in l_sysid.
         */
        if (nfsv4_sysid == 0)
                nfsv4_sysid = nlm_acquire_next_sysid();
        fl.l_pid = (pid_t)0;
        fl.l_sysid = (int)nfsv4_sysid;

        if (ftype == F_UNLCK)
                error = VOP_ADVLOCK(vp, (caddr_t)td->td_proc, F_UNLCK, &fl,
                    (F_POSIX | F_REMOTE));
        else
                error = VOP_ADVLOCK(vp, (caddr_t)td->td_proc, F_SETLK, &fl,
                    (F_POSIX | F_REMOTE));

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

/*
 * Check the nfsv4 root exports.
 */
int
nfsvno_v4rootexport(struct nfsrv_descript *nd)
{
        struct ucred *credanon;
        int exflags, error = 0, numsecflavor, *secflavors, i;

        error = vfs_stdcheckexp(&nfsv4root_mnt, nd->nd_nam, &exflags,
            &credanon, &numsecflavor, &secflavors);
        if (error) {
                error = NFSERR_PROGUNAVAIL;
                goto out;
        }
        if (credanon != NULL)
                crfree(credanon);
        for (i = 0; i < numsecflavor; i++) {
                if (secflavors[i] == AUTH_SYS)
                        nd->nd_flag |= ND_EXAUTHSYS;
                else if (secflavors[i] == RPCSEC_GSS_KRB5)
                        nd->nd_flag |= ND_EXGSS;
                else if (secflavors[i] == RPCSEC_GSS_KRB5I)
                        nd->nd_flag |= ND_EXGSSINTEGRITY;
                else if (secflavors[i] == RPCSEC_GSS_KRB5P)
                        nd->nd_flag |= ND_EXGSSPRIVACY;
        }

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

/*
 * Nfs server pseudo system call for the nfsd's
 */
/*
 * MPSAFE
 */
static int
nfssvc_nfsd(struct thread *td, struct nfssvc_args *uap)
{
        struct file *fp;
        struct nfsd_addsock_args sockarg;
        struct nfsd_nfsd_args nfsdarg;
        cap_rights_t rights;
        int error;

        if (uap->flag & NFSSVC_NFSDADDSOCK) {
                error = copyin(uap->argp, (caddr_t)&sockarg, sizeof (sockarg));
                if (error)
                        goto out;
                /*
                 * Since we don't know what rights might be required,
                 * pretend that we need them all. It is better to be too
                 * careful than too reckless.
                 */
                error = fget(td, sockarg.sock,
                    cap_rights_init(&rights, CAP_SOCK_SERVER), &fp);
                if (error != 0)
                        goto out;
                if (fp->f_type != DTYPE_SOCKET) {
                        fdrop(fp, td);
                        error = EPERM;
                        goto out;
                }
                error = nfsrvd_addsock(fp);
                fdrop(fp, td);
        } else if (uap->flag & NFSSVC_NFSDNFSD) {
                if (uap->argp == NULL) {
                        error = EINVAL;
                        goto out;
                }
                error = copyin(uap->argp, (caddr_t)&nfsdarg,
                    sizeof (nfsdarg));
                if (error)
                        goto out;
                error = nfsrvd_nfsd(td, &nfsdarg);
        } else {
                error = nfssvc_srvcall(td, uap, td->td_ucred);
        }

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

static int
nfssvc_srvcall(struct thread *p, struct nfssvc_args *uap, struct ucred *cred)
{
        struct nfsex_args export;
        struct file *fp = NULL;
        int stablefd, len;
        struct nfsd_clid adminrevoke;
        struct nfsd_dumplist dumplist;
        struct nfsd_dumpclients *dumpclients;
        struct nfsd_dumplocklist dumplocklist;
        struct nfsd_dumplocks *dumplocks;
        struct nameidata nd;
        vnode_t vp;
        int error = EINVAL, igotlock;
        struct proc *procp;
        static int suspend_nfsd = 0;

        if (uap->flag & NFSSVC_PUBLICFH) {
                NFSBZERO((caddr_t)&nfs_pubfh.nfsrvfh_data,
                    sizeof (fhandle_t));
                error = copyin(uap->argp,
                    &nfs_pubfh.nfsrvfh_data, sizeof (fhandle_t));
                if (!error)
                        nfs_pubfhset = 1;
        } else if (uap->flag & NFSSVC_V4ROOTEXPORT) {
                error = copyin(uap->argp,(caddr_t)&export,
                    sizeof (struct nfsex_args));
                if (!error)
                        error = nfsrv_v4rootexport(&export, cred, p);
        } else if (uap->flag & NFSSVC_NOPUBLICFH) {
                nfs_pubfhset = 0;
                error = 0;
        } else if (uap->flag & NFSSVC_STABLERESTART) {
                error = copyin(uap->argp, (caddr_t)&stablefd,
                    sizeof (int));
                if (!error)
                        error = fp_getfvp(p, stablefd, &fp, &vp);
                if (!error && (NFSFPFLAG(fp) & (FREAD | FWRITE)) != (FREAD | FWRITE))
                        error = EBADF;
                if (!error && newnfs_numnfsd != 0)
                        error = EPERM;
                if (!error) {
                        nfsrv_stablefirst.nsf_fp = fp;
                        nfsrv_setupstable(p);
                }
        } else if (uap->flag & NFSSVC_ADMINREVOKE) {
                error = copyin(uap->argp, (caddr_t)&adminrevoke,
                    sizeof (struct nfsd_clid));
                if (!error)
                        error = nfsrv_adminrevoke(&adminrevoke, p);
        } else if (uap->flag & NFSSVC_DUMPCLIENTS) {
                error = copyin(uap->argp, (caddr_t)&dumplist,
                    sizeof (struct nfsd_dumplist));
                if (!error && (dumplist.ndl_size < 1 ||
                        dumplist.ndl_size > NFSRV_MAXDUMPLIST))
                        error = EPERM;
                if (!error) {
                    len = sizeof (struct nfsd_dumpclients) * dumplist.ndl_size;
                    dumpclients = (struct nfsd_dumpclients *)malloc(len,
                        M_TEMP, M_WAITOK);
                    nfsrv_dumpclients(dumpclients, dumplist.ndl_size);
                    error = copyout(dumpclients,
                        CAST_USER_ADDR_T(dumplist.ndl_list), len);
                    free((caddr_t)dumpclients, M_TEMP);
                }
        } else if (uap->flag & NFSSVC_DUMPLOCKS) {
                error = copyin(uap->argp, (caddr_t)&dumplocklist,
                    sizeof (struct nfsd_dumplocklist));
                if (!error && (dumplocklist.ndllck_size < 1 ||
                        dumplocklist.ndllck_size > NFSRV_MAXDUMPLIST))
                        error = EPERM;
                if (!error)
                        error = nfsrv_lookupfilename(&nd,
                                dumplocklist.ndllck_fname, p);
                if (!error) {
                        len = sizeof (struct nfsd_dumplocks) *
                                dumplocklist.ndllck_size;
                        dumplocks = (struct nfsd_dumplocks *)malloc(len,
                                M_TEMP, M_WAITOK);
                        nfsrv_dumplocks(nd.ni_vp, dumplocks,
                            dumplocklist.ndllck_size, p);
                        vput(nd.ni_vp);
                        error = copyout(dumplocks,
                            CAST_USER_ADDR_T(dumplocklist.ndllck_list), len);
                        free((caddr_t)dumplocks, M_TEMP);
                }
        } else if (uap->flag & NFSSVC_BACKUPSTABLE) {
                procp = p->td_proc;
                PROC_LOCK(procp);
                nfsd_master_pid = procp->p_pid;
                bcopy(procp->p_comm, nfsd_master_comm, MAXCOMLEN + 1);
                nfsd_master_start = procp->p_stats->p_start;
                nfsd_master_proc = procp;
                PROC_UNLOCK(procp);
        } else if ((uap->flag & NFSSVC_SUSPENDNFSD) != 0) {
                NFSLOCKV4ROOTMUTEX();
                if (suspend_nfsd == 0) {
                        /* Lock out all nfsd threads */
                        do {
                                igotlock = nfsv4_lock(&nfsd_suspend_lock, 1,
                                    NULL, NFSV4ROOTLOCKMUTEXPTR, NULL);
                        } while (igotlock == 0 && suspend_nfsd == 0);
                        suspend_nfsd = 1;
                }
                NFSUNLOCKV4ROOTMUTEX();
                error = 0;
        } else if ((uap->flag & NFSSVC_RESUMENFSD) != 0) {
                NFSLOCKV4ROOTMUTEX();
                if (suspend_nfsd != 0) {
                        nfsv4_unlock(&nfsd_suspend_lock, 0);
                        suspend_nfsd = 0;
                }
                NFSUNLOCKV4ROOTMUTEX();
                error = 0;
        }

        NFSEXITCODE(error);
        return (error);
}

/*
 * Check exports.
 * Returns 0 if ok, 1 otherwise.
 */
int
nfsvno_testexp(struct nfsrv_descript *nd, struct nfsexstuff *exp)
{
        int i;

        /*
         * This seems odd, but allow the case where the security flavor
         * list is empty. This happens when NFSv4 is traversing non-exported
         * file systems. Exported file systems should always have a non-empty
         * security flavor list.
         */
        if (exp->nes_numsecflavor == 0)
                return (0);

        for (i = 0; i < exp->nes_numsecflavor; i++) {
                /*
                 * The tests for privacy and integrity must be first,
                 * since ND_GSS is set for everything but AUTH_SYS.
                 */
                if (exp->nes_secflavors[i] == RPCSEC_GSS_KRB5P &&
                    (nd->nd_flag & ND_GSSPRIVACY))
                        return (0);
                if (exp->nes_secflavors[i] == RPCSEC_GSS_KRB5I &&
                    (nd->nd_flag & ND_GSSINTEGRITY))
                        return (0);
                if (exp->nes_secflavors[i] == RPCSEC_GSS_KRB5 &&
                    (nd->nd_flag & ND_GSS))
                        return (0);
                if (exp->nes_secflavors[i] == AUTH_SYS &&
                    (nd->nd_flag & ND_GSS) == 0)
                        return (0);
        }
        return (1);
}

/*
 * Calculate a hash value for the fid in a file handle.
 */
uint32_t
nfsrv_hashfh(fhandle_t *fhp)
{
        uint32_t hashval;

        hashval = hash32_buf(&fhp->fh_fid, sizeof(struct fid), 0);
        return (hashval);
}

/*
 * Calculate a hash value for the sessionid.
 */
uint32_t
nfsrv_hashsessionid(uint8_t *sessionid)
{
        uint32_t hashval;

        hashval = hash32_buf(sessionid, NFSX_V4SESSIONID, 0);
        return (hashval);
}

/*
 * Signal the userland master nfsd to backup the stable restart file.
 */
void
nfsrv_backupstable(void)
{
        struct proc *procp;

        if (nfsd_master_proc != NULL) {
                procp = pfind(nfsd_master_pid);
                /* Try to make sure it is the correct process. */
                if (procp == nfsd_master_proc &&
                    procp->p_stats->p_start.tv_sec ==
                    nfsd_master_start.tv_sec &&
                    procp->p_stats->p_start.tv_usec ==
                    nfsd_master_start.tv_usec &&
                    strcmp(procp->p_comm, nfsd_master_comm) == 0)
                        kern_psignal(procp, SIGUSR2);
                else
                        nfsd_master_proc = NULL;

                if (procp != NULL)
                        PROC_UNLOCK(procp);
        }
}

extern int (*nfsd_call_nfsd)(struct thread *, struct nfssvc_args *);

/*
 * Called once to initialize data structures...
 */
static int
nfsd_modevent(module_t mod, int type, void *data)
{
        int error = 0, i;
        static int loaded = 0;

        switch (type) {
        case MOD_LOAD:
                if (loaded)
                        goto out;
                newnfs_portinit();
                for (i = 0; i < NFSRVCACHE_HASHSIZE; i++) {
                        mtx_init(&nfsrchash_table[i].mtx, "nfsrtc", NULL,
                            MTX_DEF);
                        mtx_init(&nfsrcahash_table[i].mtx, "nfsrtca", NULL,
                            MTX_DEF);
                }
                mtx_init(&nfsrc_udpmtx, "nfsuc", NULL, MTX_DEF);
                mtx_init(&nfs_v4root_mutex, "nfs4rt", NULL, MTX_DEF);
                mtx_init(&nfsv4root_mnt.mnt_mtx, "nfs4mnt", NULL, MTX_DEF);
                lockinit(&nfsv4root_mnt.mnt_explock, PVFS, "explock", 0, 0);
                nfsrvd_initcache();
                nfsd_init();
                NFSD_LOCK();
                nfsrvd_init(0);
                NFSD_UNLOCK();
                nfsd_mntinit();
#ifdef VV_DISABLEDELEG
                vn_deleg_ops.vndeleg_recall = nfsd_recalldelegation;
                vn_deleg_ops.vndeleg_disable = nfsd_disabledelegation;
#endif
                nfsd_call_servertimer = nfsrv_servertimer;
                nfsd_call_nfsd = nfssvc_nfsd;
                loaded = 1;
                break;

        case MOD_UNLOAD:
                if (newnfs_numnfsd != 0) {
                        error = EBUSY;
                        break;
                }

#ifdef VV_DISABLEDELEG
                vn_deleg_ops.vndeleg_recall = NULL;
                vn_deleg_ops.vndeleg_disable = NULL;
#endif
                nfsd_call_servertimer = NULL;
                nfsd_call_nfsd = NULL;

                /* Clean out all NFSv4 state. */
                nfsrv_throwawayallstate(curthread);

                /* Clean the NFS server reply cache */
                nfsrvd_cleancache();

                /* Free up the krpc server pool. */
                if (nfsrvd_pool != NULL)
                        svcpool_destroy(nfsrvd_pool);

                /* and get rid of the locks */
                for (i = 0; i < NFSRVCACHE_HASHSIZE; i++) {
                        mtx_destroy(&nfsrchash_table[i].mtx);
                        mtx_destroy(&nfsrcahash_table[i].mtx);
                }
                mtx_destroy(&nfsrc_udpmtx);
                mtx_destroy(&nfs_v4root_mutex);
                mtx_destroy(&nfsv4root_mnt.mnt_mtx);
                for (i = 0; i < nfsrv_sessionhashsize; i++)
                        mtx_destroy(&nfssessionhash[i].mtx);
                lockdestroy(&nfsv4root_mnt.mnt_explock);
                free(nfsclienthash, M_NFSDCLIENT);
                free(nfslockhash, M_NFSDLOCKFILE);
                free(nfssessionhash, M_NFSDSESSION);
                loaded = 0;
                break;
        default:
                error = EOPNOTSUPP;
                break;
        }

out:
        NFSEXITCODE(error);
        return (error);
}
static moduledata_t nfsd_mod = {
        "nfsd",
        nfsd_modevent,
        NULL,
};
DECLARE_MODULE(nfsd, nfsd_mod, SI_SUB_VFS, SI_ORDER_ANY);

/* So that loader and kldload(2) can find us, wherever we are.. */
MODULE_VERSION(nfsd, 1);
MODULE_DEPEND(nfsd, nfscommon, 1, 1, 1);
MODULE_DEPEND(nfsd, nfslock, 1, 1, 1);
MODULE_DEPEND(nfsd, nfslockd, 1, 1, 1);
MODULE_DEPEND(nfsd, krpc, 1, 1, 1);
MODULE_DEPEND(nfsd, nfssvc, 1, 1, 1);