FreeBSD/Linux Kernel Cross Reference
sys/fs/nfsserver/nfs_nfsdport.c

     /*-
      * 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("$FreeBSD$");
    
    #include <sys/capsicum.h>
    
    /*
     * 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/nfsport.h>
    #include <sys/hash.h>
    #include <sys/sysctl.h>
    #include <nlm/nlm_prot.h>
    #include <nlm/nlm.h>
    
    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;
    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, "New 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 new 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)(vm_offset_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_strictrelative = 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 = NFSMSIZ(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 = min(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 = min(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;
           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 = min(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;
           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, 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 boundry, super-align to page boundry.
                   */
                  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
                                                  NFSSETBIT_ATTRBIT(attrbitp,
                                                      NFSATTRBIT_TIMEACCESS);
                                  } 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, nd);
                  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 0
          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 (nd->nd_flag & ND_NFSV4) {
                          nd->nd_repstat = NFSERR_NOTSAME;
                  } else {
                          nd->nd_repstat = NFSERR_BAD_COOKIE;
                  }
              }
          }
  #endif
          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;
          }
  
          /*
           * For now ZFS requires VOP_LOOKUP as a workaround.  Until ino_t is changed
           * to 64 bit type a ZFS filesystem with over 1 billion files in it
           * will suffer from 64bit -> 32bit truncation.
           */
          if (is_zfs == 1)
                  usevget = 0;
  
          cn.cn_nameiop = LOOKUP;
          cn.cn_lkflags = LK_SHARED | LK_RETRY;
          cn.cn_cred = nd->nd_cred;
          cn.cn_thread = p;
  
          /*
           * 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) {
                                                  usevget = 0;
                                                  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 we failed to look up the entry, then it
                                   * has become invalid, most likely removed.
                                   */
                                  if (r != 0) {
                                          if (needs_unbusy)
                                                  vfs_unbusy(new_mp);
                                          goto invalid;
                                  }
                                  KASSERT(refp != NULL || nvp != NULL,
                                      ("%s: undetected lookup error", __func__));
  
                                  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;
                                          }
                                  }
  
                                  /*
                                   * If we failed to get attributes of the entry,
                                   * then just skip it for NFSv3 (the traditional
                                   * behavior in the old NFS server).
                                   * For NFSv4 the behavior is controlled by
                                   * RDATTRERROR: we either ignore the error or
                                   * fail the request.
                                   * Note that RDATTRERROR is never set for NFSv3.
                                   */
                                  if (r != 0) {
                                          if (!NFSISSET_ATTRBIT(&attrbits,
                                              NFSATTRBIT_RDATTRERROR)) {
                                                  vput(nvp);
                                                  if (needs_unbusy != 0)
                                                          vfs_unbusy(new_mp);
                                                  if ((nd->nd_flag & ND_NFSV3))
                                                          goto invalid;
                                                  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++;
                  }
  invalid:
                  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, 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, 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, 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);
                          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 priviledges,
           * 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 psuedo 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);