/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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.
 * 3. 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.
 *
 *      from nfs_vnops.c        8.16 (Berkeley) 5/27/95
 */

#include <sys/cdefs.h>
/*
 * vnode op calls for Sun NFS version 2, 3 and 4
 */

#include "opt_inet.h"

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/resourcevar.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/extattr.h>
#include <sys/filio.h>
#include <sys/jail.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/namei.h>
#include <sys/socket.h>
#include <sys/vnode.h>
#include <sys/dirent.h>
#include <sys/fcntl.h>
#include <sys/lockf.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/signalvar.h>

#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_object.h>
#include <vm/vnode_pager.h>

#include <fs/nfs/nfsport.h>
#include <fs/nfsclient/nfsnode.h>
#include <fs/nfsclient/nfsmount.h>
#include <fs/nfsclient/nfs.h>
#include <fs/nfsclient/nfs_kdtrace.h>

#include <net/if.h>
#include <netinet/in.h>
#include <netinet/in_var.h>

#include <nfs/nfs_lock.h>

#ifdef KDTRACE_HOOKS
#include <sys/dtrace_bsd.h>

dtrace_nfsclient_accesscache_flush_probe_func_t
                dtrace_nfscl_accesscache_flush_done_probe;
uint32_t        nfscl_accesscache_flush_done_id;

dtrace_nfsclient_accesscache_get_probe_func_t
                dtrace_nfscl_accesscache_get_hit_probe,
                dtrace_nfscl_accesscache_get_miss_probe;
uint32_t        nfscl_accesscache_get_hit_id;
uint32_t        nfscl_accesscache_get_miss_id;

dtrace_nfsclient_accesscache_load_probe_func_t
                dtrace_nfscl_accesscache_load_done_probe;
uint32_t        nfscl_accesscache_load_done_id;
#endif /* !KDTRACE_HOOKS */

/* Defs */
#define TRUE    1
#define FALSE   0

extern struct nfsstatsv1 nfsstatsv1;
extern int nfsrv_useacl;
extern int nfscl_debuglevel;
NFSCLSTATEMUTEX;
MALLOC_DECLARE(M_NEWNFSREQ);

static vop_read_t       nfsfifo_read;
static vop_write_t      nfsfifo_write;
static vop_close_t      nfsfifo_close;
static int      nfs_setattrrpc(struct vnode *, struct vattr *, struct ucred *,
                    struct thread *);
static int      nfs_get_namedattrdir(struct vnode *, struct componentname *,
            struct vnode **);
static vop_lookup_t     nfs_lookup;
static vop_create_t     nfs_create;
static vop_mknod_t      nfs_mknod;
static vop_open_t       nfs_open;
static vop_pathconf_t   nfs_pathconf;
static vop_close_t      nfs_close;
static vop_access_t     nfs_access;
static vop_getattr_t    nfs_getattr;
static vop_setattr_t    nfs_setattr;
static vop_read_t       nfs_read;
static vop_fsync_t      nfs_fsync;
static vop_remove_t     nfs_remove;
static vop_link_t       nfs_link;
static vop_rename_t     nfs_rename;
static vop_mkdir_t      nfs_mkdir;
static vop_rmdir_t      nfs_rmdir;
static vop_symlink_t    nfs_symlink;
static vop_readdir_t    nfs_readdir;
static vop_strategy_t   nfs_strategy;
static  int     nfs_lookitup(struct vnode *, char *, int,
                    struct ucred *, struct thread *, struct nfsnode **);
static  int     nfs_sillyrename(struct vnode *, struct vnode *,
                    struct componentname *);
static vop_access_t     nfsspec_access;
static vop_readlink_t   nfs_readlink;
static vop_print_t      nfs_print;
static vop_advlock_t    nfs_advlock;
static vop_advlockasync_t nfs_advlockasync;
static vop_getacl_t nfs_getacl;
static vop_setacl_t nfs_setacl;
static vop_advise_t nfs_advise;
static vop_allocate_t nfs_allocate;
static vop_deallocate_t nfs_deallocate;
static vop_copy_file_range_t nfs_copy_file_range;
static vop_ioctl_t nfs_ioctl;
static vop_getextattr_t nfs_getextattr;
static vop_setextattr_t nfs_setextattr;
static vop_listextattr_t nfs_listextattr;
static vop_deleteextattr_t nfs_deleteextattr;
static vop_delayed_setsize_t    nfs_delayed_setsize;

/*
 * Global vfs data structures for nfs
 */

static struct vop_vector newnfs_vnodeops_nosig = {
        .vop_default =          &default_vnodeops,
        .vop_access =           nfs_access,
        .vop_advlock =          nfs_advlock,
        .vop_advlockasync =     nfs_advlockasync,
        .vop_close =            nfs_close,
        .vop_create =           nfs_create,
        .vop_delayed_setsize =  nfs_delayed_setsize,
        .vop_fsync =            nfs_fsync,
        .vop_getattr =          nfs_getattr,
        .vop_getpages =         ncl_getpages,
        .vop_putpages =         ncl_putpages,
        .vop_inactive =         ncl_inactive,
        .vop_link =             nfs_link,
        .vop_lookup =           nfs_lookup,
        .vop_mkdir =            nfs_mkdir,
        .vop_mknod =            nfs_mknod,
        .vop_open =             nfs_open,
        .vop_pathconf =         nfs_pathconf,
        .vop_print =            nfs_print,
        .vop_read =             nfs_read,
        .vop_readdir =          nfs_readdir,
        .vop_readlink =         nfs_readlink,
        .vop_reclaim =          ncl_reclaim,
        .vop_remove =           nfs_remove,
        .vop_rename =           nfs_rename,
        .vop_rmdir =            nfs_rmdir,
        .vop_setattr =          nfs_setattr,
        .vop_strategy =         nfs_strategy,
        .vop_symlink =          nfs_symlink,
        .vop_write =            ncl_write,
        .vop_getacl =           nfs_getacl,
        .vop_setacl =           nfs_setacl,
        .vop_advise =           nfs_advise,
        .vop_allocate =         nfs_allocate,
        .vop_deallocate =       nfs_deallocate,
        .vop_copy_file_range =  nfs_copy_file_range,
        .vop_ioctl =            nfs_ioctl,
        .vop_getextattr =       nfs_getextattr,
        .vop_setextattr =       nfs_setextattr,
        .vop_listextattr =      nfs_listextattr,
        .vop_deleteextattr =    nfs_deleteextattr,
};
VFS_VOP_VECTOR_REGISTER(newnfs_vnodeops_nosig);

static int
nfs_vnodeops_bypass(struct vop_generic_args *a)
{

        return (vop_sigdefer(&newnfs_vnodeops_nosig, a));
}

struct vop_vector newnfs_vnodeops = {
        .vop_default =          &default_vnodeops,
        .vop_bypass =           nfs_vnodeops_bypass,
};
VFS_VOP_VECTOR_REGISTER(newnfs_vnodeops);

static struct vop_vector newnfs_fifoops_nosig = {
        .vop_default =          &fifo_specops,
        .vop_access =           nfsspec_access,
        .vop_close =            nfsfifo_close,
        .vop_fsync =            nfs_fsync,
        .vop_getattr =          nfs_getattr,
        .vop_inactive =         ncl_inactive,
        .vop_pathconf =         nfs_pathconf,
        .vop_print =            nfs_print,
        .vop_read =             nfsfifo_read,
        .vop_reclaim =          ncl_reclaim,
        .vop_setattr =          nfs_setattr,
        .vop_write =            nfsfifo_write,
};
VFS_VOP_VECTOR_REGISTER(newnfs_fifoops_nosig);

static int
nfs_fifoops_bypass(struct vop_generic_args *a)
{

        return (vop_sigdefer(&newnfs_fifoops_nosig, a));
}

struct vop_vector newnfs_fifoops = {
        .vop_default =          &default_vnodeops,
        .vop_bypass =           nfs_fifoops_bypass,
};
VFS_VOP_VECTOR_REGISTER(newnfs_fifoops);

static int nfs_mknodrpc(struct vnode *dvp, struct vnode **vpp,
    struct componentname *cnp, struct vattr *vap);
static int nfs_removerpc(struct vnode *dvp, struct vnode *vp, char *name,
    int namelen, struct ucred *cred, struct thread *td, bool silly);
static void nfs_removestatus(struct vnode *vp, nfsremove_status file_status,
    bool silly, struct thread *td);
static int nfs_renamerpc(struct vnode *fdvp, struct vnode *fvp,
    char *fnameptr, int fnamelen, struct vnode *tdvp, struct vnode *tvp,
    char *tnameptr, int tnamelen, bool silly, struct ucred *cred,
    struct thread *td);
static int nfs_renameit(struct vnode *sdvp, struct vnode *svp,
    struct componentname *scnp, struct sillyrename *sp);

/*
 * Global variables
 */
SYSCTL_DECL(_vfs_nfs);

static int      nfsaccess_cache_timeout = NFS_MAXATTRTIMO;
SYSCTL_INT(_vfs_nfs, OID_AUTO, access_cache_timeout, CTLFLAG_RW,
           &nfsaccess_cache_timeout, 0, "NFS ACCESS cache timeout");

static int      nfs_prime_access_cache = 0;
SYSCTL_INT(_vfs_nfs, OID_AUTO, prime_access_cache, CTLFLAG_RW,
           &nfs_prime_access_cache, 0,
           "Prime NFS ACCESS cache when fetching attributes");

static int      newnfs_commit_on_close = 0;
SYSCTL_INT(_vfs_nfs, OID_AUTO, commit_on_close, CTLFLAG_RW,
    &newnfs_commit_on_close, 0, "write+commit on close, else only write");

static int      nfs_clean_pages_on_close = 1;
SYSCTL_INT(_vfs_nfs, OID_AUTO, clean_pages_on_close, CTLFLAG_RW,
           &nfs_clean_pages_on_close, 0, "NFS clean dirty pages on close");

int newnfs_directio_enable = 0;
SYSCTL_INT(_vfs_nfs, OID_AUTO, nfs_directio_enable, CTLFLAG_RW,
           &newnfs_directio_enable, 0, "Enable NFS directio");

int nfs_keep_dirty_on_error;
SYSCTL_INT(_vfs_nfs, OID_AUTO, nfs_keep_dirty_on_error, CTLFLAG_RW,
    &nfs_keep_dirty_on_error, 0, "Retry pageout if error returned");

/*
 * This sysctl allows other processes to mmap a file that has been opened
 * O_DIRECT by a process.  In general, having processes mmap the file while
 * Direct IO is in progress can lead to Data Inconsistencies.  But, we allow
 * this by default to prevent DoS attacks - to prevent a malicious user from
 * opening up files O_DIRECT preventing other users from mmap'ing these
 * files.  "Protected" environments where stricter consistency guarantees are
 * required can disable this knob.  The process that opened the file O_DIRECT
 * cannot mmap() the file, because mmap'ed IO on an O_DIRECT open() is not
 * meaningful.
 */
int newnfs_directio_allow_mmap = 1;
SYSCTL_INT(_vfs_nfs, OID_AUTO, nfs_directio_allow_mmap, CTLFLAG_RW,
           &newnfs_directio_allow_mmap, 0, "Enable mmaped IO on file with O_DIRECT opens");

static uint64_t nfs_maxalloclen = 64 * 1024 * 1024;
SYSCTL_U64(_vfs_nfs, OID_AUTO, maxalloclen, CTLFLAG_RW,
           &nfs_maxalloclen, 0, "NFS max allocate/deallocate length");

#define NFSACCESS_ALL (NFSACCESS_READ | NFSACCESS_MODIFY                \
                         | NFSACCESS_EXTEND | NFSACCESS_EXECUTE \
                         | NFSACCESS_DELETE | NFSACCESS_LOOKUP)

/*
 * SMP Locking Note :
 * The list of locks after the description of the lock is the ordering
 * of other locks acquired with the lock held.
 * np->n_mtx : Protects the fields in the nfsnode.
       VM Object Lock
       VI_MTX (acquired indirectly)
 * nmp->nm_mtx : Protects the fields in the nfsmount.
       rep->r_mtx
 * ncl_iod_mutex : Global lock, protects shared nfsiod state.
 * nfs_reqq_mtx : Global lock, protects the nfs_reqq list.
       nmp->nm_mtx
       rep->r_mtx
 * rep->r_mtx : Protects the fields in an nfsreq.
 */

static int
nfs_delayed_setsize(struct vop_delayed_setsize_args *ap)
{
        struct vnode *vp;
        struct nfsnode *np;
        u_quad_t nsize;

        vp = ap->a_vp;
        np = VTONFS(vp);
        if (np != NULL) {
                NFSLOCKNODE(np);
                nsize = np->n_size;
                NFSUNLOCKNODE(np);
                vnode_pager_setsize(vp, nsize);
        }
        return (0);
}

static int
nfs34_access_otw(struct vnode *vp, int wmode, struct thread *td,
    struct ucred *cred, u_int32_t *retmode)
{
        int error = 0, attrflag, i, lrupos;
        u_int32_t rmode;
        struct nfsnode *np = VTONFS(vp);
        struct nfsvattr nfsva;

        error = nfsrpc_accessrpc(vp, wmode, cred, td, &nfsva, &attrflag,
            &rmode);
        if (attrflag)
                (void) nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
        if (!error) {
                lrupos = 0;
                NFSLOCKNODE(np);
                for (i = 0; i < NFS_ACCESSCACHESIZE; i++) {
                        if (np->n_accesscache[i].uid == cred->cr_uid) {
                                np->n_accesscache[i].mode = rmode;
                                np->n_accesscache[i].stamp = time_second;
                                break;
                        }
                        if (i > 0 && np->n_accesscache[i].stamp <
                            np->n_accesscache[lrupos].stamp)
                                lrupos = i;
                }
                if (i == NFS_ACCESSCACHESIZE) {
                        np->n_accesscache[lrupos].uid = cred->cr_uid;
                        np->n_accesscache[lrupos].mode = rmode;
                        np->n_accesscache[lrupos].stamp = time_second;
                }
                NFSUNLOCKNODE(np);
                if (retmode != NULL)
                        *retmode = rmode;
                KDTRACE_NFS_ACCESSCACHE_LOAD_DONE(vp, cred->cr_uid, rmode, 0);
        } else if (NFS_ISV4(vp)) {
                error = nfscl_maperr(td, error, (uid_t)0, (gid_t)0);
        }
#ifdef KDTRACE_HOOKS
        if (error != 0)
                KDTRACE_NFS_ACCESSCACHE_LOAD_DONE(vp, cred->cr_uid, 0,
                    error);
#endif
        return (error);
}

/*
 * nfs access vnode op.
 * For nfs version 2, just return ok. File accesses may fail later.
 * For nfs version 3, use the access rpc to check accessibility. If file modes
 * are changed on the server, accesses might still fail later.
 */
static int
nfs_access(struct vop_access_args *ap)
{
        struct vnode *vp = ap->a_vp;
        int error = 0, i, gotahit;
        u_int32_t mode, wmode, rmode;
        int v34 = NFS_ISV34(vp);
        struct nfsnode *np = VTONFS(vp);

        /*
         * Disallow write attempts on filesystems mounted read-only;
         * unless the file is a socket, fifo, or a block or character
         * device resident on the filesystem.
         */
        if ((ap->a_accmode & (VWRITE | VAPPEND | VWRITE_NAMED_ATTRS |
            VDELETE_CHILD | VWRITE_ATTRIBUTES | VDELETE | VWRITE_ACL |
            VWRITE_OWNER)) != 0 && (vp->v_mount->mnt_flag & MNT_RDONLY) != 0) {
                switch (vp->v_type) {
                case VREG:
                case VDIR:
                case VLNK:
                        return (EROFS);
                default:
                        break;
                }
        }

        /*
         * For NFSv4, check for a delegation with an Allow ACE, to see
         * if that permits access.
         */
        if ((VFSTONFS(vp->v_mount)->nm_flag & NFSMNT_NOCTO) != 0) {
                error = nfscl_delegacecheck(vp, ap->a_accmode, ap->a_cred);
                if (error == 0)
                        return (error);
                error = 0;
        }

        /*
         * For nfs v3 or v4, check to see if we have done this recently, and if
         * so return our cached result instead of making an ACCESS call.
         * If not, do an access rpc, otherwise you are stuck emulating
         * ufs_access() locally using the vattr. This may not be correct,
         * since the server may apply other access criteria such as
         * client uid-->server uid mapping that we do not know about.
         */
        if (v34) {
                if (ap->a_accmode & VREAD)
                        mode = NFSACCESS_READ;
                else
                        mode = 0;
                if (vp->v_type != VDIR) {
                        if (ap->a_accmode & VWRITE)
                                mode |= (NFSACCESS_MODIFY | NFSACCESS_EXTEND);
                        if (ap->a_accmode & VAPPEND)
                                mode |= NFSACCESS_EXTEND;
                        if (ap->a_accmode & VEXEC)
                                mode |= NFSACCESS_EXECUTE;
                        if (ap->a_accmode & VDELETE)
                                mode |= NFSACCESS_DELETE;
                } else {
                        if (ap->a_accmode & VWRITE)
                                mode |= (NFSACCESS_MODIFY | NFSACCESS_EXTEND);
                        if (ap->a_accmode & VAPPEND)
                                mode |= NFSACCESS_EXTEND;
                        if (ap->a_accmode & VEXEC)
                                mode |= NFSACCESS_LOOKUP;
                        if (ap->a_accmode & VDELETE)
                                mode |= NFSACCESS_DELETE;
                        if (ap->a_accmode & VDELETE_CHILD)
                                mode |= NFSACCESS_MODIFY;
                }
                /* XXX safety belt, only make blanket request if caching */
                if (nfsaccess_cache_timeout > 0) {
                        wmode = NFSACCESS_READ | NFSACCESS_MODIFY |
                                NFSACCESS_EXTEND | NFSACCESS_EXECUTE |
                                NFSACCESS_DELETE | NFSACCESS_LOOKUP;
                } else {
                        wmode = mode;
                }

                /*
                 * Does our cached result allow us to give a definite yes to
                 * this request?
                 */
                gotahit = 0;
                NFSLOCKNODE(np);
                for (i = 0; i < NFS_ACCESSCACHESIZE; i++) {
                        if (ap->a_cred->cr_uid == np->n_accesscache[i].uid) {
                            if (time_second < (np->n_accesscache[i].stamp
                                + nfsaccess_cache_timeout) &&
                                (np->n_accesscache[i].mode & mode) == mode) {
                                NFSINCRGLOBAL(nfsstatsv1.accesscache_hits);
                                gotahit = 1;
                            }
                            break;
                        }
                }
                NFSUNLOCKNODE(np);
#ifdef KDTRACE_HOOKS
                if (gotahit != 0)
                        KDTRACE_NFS_ACCESSCACHE_GET_HIT(vp,
                            ap->a_cred->cr_uid, mode);
                else
                        KDTRACE_NFS_ACCESSCACHE_GET_MISS(vp,
                            ap->a_cred->cr_uid, mode);
#endif
                if (gotahit == 0) {
                        /*
                         * Either a no, or a don't know.  Go to the wire.
                         */
                        NFSINCRGLOBAL(nfsstatsv1.accesscache_misses);
                        error = nfs34_access_otw(vp, wmode, ap->a_td,
                            ap->a_cred, &rmode);
                        if (!error &&
                            (rmode & mode) != mode)
                                error = EACCES;
                }
                return (error);
        } else {
                if ((error = nfsspec_access(ap)) != 0) {
                        return (error);
                }
                /*
                 * Attempt to prevent a mapped root from accessing a file
                 * which it shouldn't.  We try to read a byte from the file
                 * if the user is root and the file is not zero length.
                 * After calling nfsspec_access, we should have the correct
                 * file size cached.
                 */
                NFSLOCKNODE(np);
                if (ap->a_cred->cr_uid == 0 && (ap->a_accmode & VREAD)
                    && VTONFS(vp)->n_size > 0) {
                        struct iovec aiov;
                        struct uio auio;
                        char buf[1];

                        NFSUNLOCKNODE(np);
                        aiov.iov_base = buf;
                        aiov.iov_len = 1;
                        auio.uio_iov = &aiov;
                        auio.uio_iovcnt = 1;
                        auio.uio_offset = 0;
                        auio.uio_resid = 1;
                        auio.uio_segflg = UIO_SYSSPACE;
                        auio.uio_rw = UIO_READ;
                        auio.uio_td = ap->a_td;

                        if (vp->v_type == VREG)
                                error = ncl_readrpc(vp, &auio, ap->a_cred);
                        else if (vp->v_type == VDIR) {
                                char* bp;
                                bp = malloc(NFS_DIRBLKSIZ, M_TEMP, M_WAITOK);
                                aiov.iov_base = bp;
                                aiov.iov_len = auio.uio_resid = NFS_DIRBLKSIZ;
                                error = ncl_readdirrpc(vp, &auio, ap->a_cred,
                                    ap->a_td);
                                free(bp, M_TEMP);
                        } else if (vp->v_type == VLNK)
                                error = ncl_readlinkrpc(vp, &auio, ap->a_cred);
                        else
                                error = EACCES;
                } else
                        NFSUNLOCKNODE(np);
                return (error);
        }
}

/*
 * nfs open vnode op
 * Check to see if the type is ok
 * and that deletion is not in progress.
 * For paged in text files, you will need to flush the page cache
 * if consistency is lost.
 */
/* ARGSUSED */
static int
nfs_open(struct vop_open_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct nfsnode *np = VTONFS(vp);
        struct vattr vattr;
        int error;
        int fmode = ap->a_mode;
        struct ucred *cred;
        vm_object_t obj;

        if (vp->v_type != VREG && vp->v_type != VDIR && vp->v_type != VLNK)
                return (EOPNOTSUPP);

        /*
         * For NFSv4, we need to do the Open Op before cache validation,
         * so that we conform to RFC3530 Sec. 9.3.1.
         */
        if (NFS_ISV4(vp)) {
                error = nfsrpc_open(vp, fmode, ap->a_cred, ap->a_td);
                if (error) {
                        error = nfscl_maperr(ap->a_td, error, (uid_t)0,
                            (gid_t)0);
                        return (error);
                }
        }

        /*
         * Now, if this Open will be doing reading, re-validate/flush the
         * cache, so that Close/Open coherency is maintained.
         */
        NFSLOCKNODE(np);
        if (np->n_flag & NMODIFIED) {
                NFSUNLOCKNODE(np);
                if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
                        NFSVOPLOCK(vp, LK_UPGRADE | LK_RETRY);
                        if (VN_IS_DOOMED(vp))
                                return (EBADF);
                }
                error = ncl_vinvalbuf(vp, V_SAVE, ap->a_td, 1);
                if (error == EINTR || error == EIO) {
                        if (NFS_ISV4(vp))
                                (void) nfsrpc_close(vp, 0, ap->a_td);
                        return (error);
                }
                NFSLOCKNODE(np);
                np->n_attrstamp = 0;
                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
                if (vp->v_type == VDIR)
                        np->n_direofoffset = 0;
                NFSUNLOCKNODE(np);
                error = VOP_GETATTR(vp, &vattr, ap->a_cred);
                if (error) {
                        if (NFS_ISV4(vp))
                                (void) nfsrpc_close(vp, 0, ap->a_td);
                        return (error);
                }
                NFSLOCKNODE(np);
                np->n_mtime = vattr.va_mtime;
                if (NFS_ISV4(vp))
                        np->n_change = vattr.va_filerev;
        } else {
                NFSUNLOCKNODE(np);
                error = VOP_GETATTR(vp, &vattr, ap->a_cred);
                if (error) {
                        if (NFS_ISV4(vp))
                                (void) nfsrpc_close(vp, 0, ap->a_td);
                        return (error);
                }
                NFSLOCKNODE(np);
                if ((NFS_ISV4(vp) && np->n_change != vattr.va_filerev) ||
                    NFS_TIMESPEC_COMPARE(&np->n_mtime, &vattr.va_mtime)) {
                        if (vp->v_type == VDIR)
                                np->n_direofoffset = 0;
                        NFSUNLOCKNODE(np);
                        if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
                                NFSVOPLOCK(vp, LK_UPGRADE | LK_RETRY);
                                if (VN_IS_DOOMED(vp))
                                        return (EBADF);
                        }
                        error = ncl_vinvalbuf(vp, V_SAVE, ap->a_td, 1);
                        if (error == EINTR || error == EIO) {
                                if (NFS_ISV4(vp))
                                        (void) nfsrpc_close(vp, 0, ap->a_td);
                                return (error);
                        }
                        NFSLOCKNODE(np);
                        np->n_mtime = vattr.va_mtime;
                        if (NFS_ISV4(vp))
                                np->n_change = vattr.va_filerev;
                }
        }

        /*
         * If the object has >= 1 O_DIRECT active opens, we disable caching.
         */
        if (newnfs_directio_enable && (fmode & O_DIRECT) &&
            (vp->v_type == VREG)) {
                if (np->n_directio_opens == 0) {
                        NFSUNLOCKNODE(np);
                        if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
                                NFSVOPLOCK(vp, LK_UPGRADE | LK_RETRY);
                                if (VN_IS_DOOMED(vp))
                                        return (EBADF);
                        }
                        error = ncl_vinvalbuf(vp, V_SAVE, ap->a_td, 1);
                        if (error) {
                                if (NFS_ISV4(vp))
                                        (void) nfsrpc_close(vp, 0, ap->a_td);
                                return (error);
                        }
                        NFSLOCKNODE(np);
                        np->n_flag |= NNONCACHE;
                }
                np->n_directio_opens++;
        }

        /* If opened for writing via NFSv4.1 or later, mark that for pNFS. */
        if (NFSHASPNFS(VFSTONFS(vp->v_mount)) && (fmode & FWRITE) != 0)
                np->n_flag |= NWRITEOPENED;

        /*
         * If this is an open for writing, capture a reference to the
         * credentials, so they can be used by ncl_putpages(). Using
         * these write credentials is preferable to the credentials of
         * whatever thread happens to be doing the VOP_PUTPAGES() since
         * the write RPCs are less likely to fail with EACCES.
         */
        if ((fmode & FWRITE) != 0) {
                cred = np->n_writecred;
                np->n_writecred = crhold(ap->a_cred);
        } else
                cred = NULL;
        NFSUNLOCKNODE(np);

        if (cred != NULL)
                crfree(cred);
        vnode_create_vobject(vp, vattr.va_size, ap->a_td);

        /*
         * If the text file has been mmap'd, flush any dirty pages to the
         * buffer cache and then...
         * Make sure all writes are pushed to the NFS server.  If this is not
         * done, the modify time of the file can change while the text
         * file is being executed.  This will cause the process that is
         * executing the text file to be terminated.
         */
        if (vp->v_writecount <= -1) {
                if ((obj = vp->v_object) != NULL &&
                    vm_object_mightbedirty(obj)) {
                        if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
                                NFSVOPLOCK(vp, LK_UPGRADE | LK_RETRY);
                                if (VN_IS_DOOMED(vp))
                                        return (EBADF);
                        }
                        vnode_pager_clean_sync(vp);
                }

                /* Now, flush the buffer cache. */
                ncl_flush(vp, MNT_WAIT, curthread, 0, 0);

                /* And, finally, make sure that n_mtime is up to date. */
                np = VTONFS(vp);
                NFSLOCKNODE(np);
                np->n_mtime = np->n_vattr.na_mtime;
                NFSUNLOCKNODE(np);
        }
        return (0);
}

/*
 * nfs close vnode op
 * What an NFS client should do upon close after writing is a debatable issue.
 * Most NFS clients push delayed writes to the server upon close, basically for
 * two reasons:
 * 1 - So that any write errors may be reported back to the client process
 *     doing the close system call. By far the two most likely errors are
 *     NFSERR_NOSPC and NFSERR_DQUOT to indicate space allocation failure.
 * 2 - To put a worst case upper bound on cache inconsistency between
 *     multiple clients for the file.
 * There is also a consistency problem for Version 2 of the protocol w.r.t.
 * not being able to tell if other clients are writing a file concurrently,
 * since there is no way of knowing if the changed modify time in the reply
 * is only due to the write for this client.
 * (NFS Version 3 provides weak cache consistency data in the reply that
 *  should be sufficient to detect and handle this case.)
 *
 * The current code does the following:
 * for NFS Version 2 - play it safe and flush/invalidate all dirty buffers
 * for NFS Version 3 - flush dirty buffers to the server but don't invalidate
 *                     or commit them (this satisfies 1 and 2 except for the
 *                     case where the server crashes after this close but
 *                     before the commit RPC, which is felt to be "good
 *                     enough". Changing the last argument to ncl_flush() to
 *                     a 1 would force a commit operation, if it is felt a
 *                     commit is necessary now.
 * for NFS Version 4 - flush the dirty buffers and commit them, if
 *                     nfscl_mustflush() says this is necessary.
 *                     It is necessary if there is no write delegation held,
 *                     in order to satisfy open/close coherency.
 *                     If the file isn't cached on local stable storage,
 *                     it may be necessary in order to detect "out of space"
 *                     errors from the server, if the write delegation
 *                     issued by the server doesn't allow the file to grow.
 */
/* ARGSUSED */
static int
nfs_close(struct vop_close_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct nfsnode *np = VTONFS(vp);
        struct nfsvattr nfsva;
        struct ucred *cred;
        int error = 0, ret, localcred = 0;
        int fmode = ap->a_fflag;
        struct nfsmount *nmp;

        if (NFSCL_FORCEDISM(vp->v_mount))
                return (0);
        nmp = VFSTONFS(vp->v_mount);
        /*
         * During shutdown, a_cred isn't valid, so just use root.
         */
        if (ap->a_cred == NOCRED) {
                cred = newnfs_getcred();
                localcred = 1;
        } else {
                cred = ap->a_cred;
        }
        if (vp->v_type == VREG) {
            /*
             * Examine and clean dirty pages, regardless of NMODIFIED.
             * This closes a major hole in close-to-open consistency.
             * We want to push out all dirty pages (and buffers) on
             * close, regardless of whether they were dirtied by
             * mmap'ed writes or via write().
             */
            if (nfs_clean_pages_on_close && vp->v_object) {
                if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
                        NFSVOPLOCK(vp, LK_UPGRADE | LK_RETRY);
                        if (VN_IS_DOOMED(vp) && ap->a_fflag != FNONBLOCK)
                                return (EBADF);
                }
                vnode_pager_clean_async(vp);
            }
            NFSLOCKNODE(np);
            if (np->n_flag & NMODIFIED) {
                NFSUNLOCKNODE(np);
                if (NFS_ISV3(vp)) {
                    /*
                     * Under NFSv3 we have dirty buffers to dispose of.  We
                     * must flush them to the NFS server.  We have the option
                     * of waiting all the way through the commit rpc or just
                     * waiting for the initial write.  The default is to only
                     * wait through the initial write so the data is in the
                     * server's cache, which is roughly similar to the state
                     * a standard disk subsystem leaves the file in on close().
                     *
                     * We cannot clear the NMODIFIED bit in np->n_flag due to
                     * potential races with other processes, and certainly
                     * cannot clear it if we don't commit.
                     * These races occur when there is no longer the old
                     * traditional vnode locking implemented for Vnode Ops.
                     */
                    int cm = newnfs_commit_on_close ? 1 : 0;
                    if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
                            NFSVOPLOCK(vp, LK_UPGRADE | LK_RETRY);
                            if (VN_IS_DOOMED(vp) && ap->a_fflag != FNONBLOCK)
                                    return (EBADF);
                    }
                    error = ncl_flush(vp, MNT_WAIT, ap->a_td, cm, 0);
                    /* np->n_flag &= ~NMODIFIED; */
                } else if (NFS_ISV4(vp)) { 
                        if (!NFSHASNFSV4N(nmp) ||
                            (nmp->nm_flag & NFSMNT_NOCTO) == 0 ||
                            nfscl_mustflush(vp) != 0) {
                                int cm = newnfs_commit_on_close ? 1 : 0;
                                if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
                                        NFSVOPLOCK(vp, LK_UPGRADE | LK_RETRY);
                                        if (VN_IS_DOOMED(vp) && ap->a_fflag !=
                                            FNONBLOCK)
                                                return (EBADF);
                                }
                                error = ncl_flush(vp, MNT_WAIT, ap->a_td,
                                    cm, 0);
                                /*
                                 * as above w.r.t races when clearing
                                 * NMODIFIED.
                                 * np->n_flag &= ~NMODIFIED;
                                 */
                        }
                } else {
                        if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
                                NFSVOPLOCK(vp, LK_UPGRADE | LK_RETRY);
                                if (VN_IS_DOOMED(vp) && ap->a_fflag !=
                                    FNONBLOCK)
                                        return (EBADF);
                        }
                        error = ncl_vinvalbuf(vp, V_SAVE, ap->a_td, 1);
                }
                NFSLOCKNODE(np);
            }
            /* 
             * Invalidate the attribute cache in all cases.
             * An open is going to fetch fresh attrs any way, other procs
             * on this node that have file open will be forced to do an 
             * otw attr fetch, but this is safe.
             * --> A user found that their RPC count dropped by 20% when
             *     this was commented out and I can't see any requirement
             *     for it, so I've disabled it when negative lookups are
             *     enabled. (What does this have to do with negative lookup
             *     caching? Well nothing, except it was reported by the
             *     same user that needed negative lookup caching and I wanted
             *     there to be a way to disable it to see if it
             *     is the cause of some caching/coherency issue that might
             *     crop up.)
             */
            if (nmp->nm_negnametimeo == 0) {
                    np->n_attrstamp = 0;
                    KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
            }
            if (np->n_flag & NWRITEERR) {
                np->n_flag &= ~NWRITEERR;
                error = np->n_error;
            }
            NFSUNLOCKNODE(np);
        }

        if (NFS_ISV4(vp)) {
                /*
                 * Get attributes so "change" is up to date.
                 */
                if (error == 0 && nfscl_nodeleg(vp, 0) != 0 &&
                    vp->v_type == VREG &&
                    (nmp->nm_flag & NFSMNT_NOCTO) == 0) {
                        ret = nfsrpc_getattr(vp, cred, ap->a_td, &nfsva);
                        if (!ret) {
                                np->n_change = nfsva.na_filerev;
                                (void) nfscl_loadattrcache(&vp, &nfsva, NULL,
                                    0, 0);
                        }
                }

                /*
                 * and do the close.
                 */
                ret = nfsrpc_close(vp, 0, ap->a_td);
                if (!error && ret)
                        error = ret;
                if (error)
                        error = nfscl_maperr(ap->a_td, error, (uid_t)0,
                            (gid_t)0);
        }
        if (newnfs_directio_enable && (fmode & O_DIRECT) && (vp->v_type == VREG)) {
                NFSLOCKNODE(np);
                KASSERT((np->n_directio_opens > 0), 
                        ("nfs_close: unexpectedly value (0) of n_directio_opens\n"));
                np->n_directio_opens--;
                if (np->n_directio_opens == 0)
                        np->n_flag &= ~NNONCACHE;
                NFSUNLOCKNODE(np);
        }
        if (localcred)
                NFSFREECRED(cred);
        return (error);
}

/*
 * nfs getattr call from vfs.
 */
static int
nfs_getattr(struct vop_getattr_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct thread *td = curthread;  /* XXX */
        struct nfsnode *np = VTONFS(vp);
        int error = 0;
        struct nfsvattr nfsva;
        struct vattr *vap = ap->a_vap;
        struct vattr vattr;
        struct nfsmount *nmp;

        nmp = VFSTONFS(vp->v_mount);
        /*
         * Update local times for special files.
         */
        NFSLOCKNODE(np);
        if (np->n_flag & (NACC | NUPD))
                np->n_flag |= NCHG;
        NFSUNLOCKNODE(np);
        /*
         * First look in the cache.
         * For "syskrb5" mounts, nm_fhsize might still be zero and
         * cached attributes should be ignored.
         */
        if (nmp->nm_fhsize > 0 && ncl_getattrcache(vp, &vattr) == 0) {
                ncl_copy_vattr(vp, vap, &vattr);

                /*
                 * Get the local modify time for the case of a write
                 * delegation.
                 */
                nfscl_deleggetmodtime(vp, &vap->va_mtime);
                return (0);
        }

        if (NFS_ISV34(vp) && nfs_prime_access_cache &&
            nfsaccess_cache_timeout > 0) {
                NFSINCRGLOBAL(nfsstatsv1.accesscache_misses);
                nfs34_access_otw(vp, NFSACCESS_ALL, td, ap->a_cred, NULL);
                if (ncl_getattrcache(vp, ap->a_vap) == 0) {
                        nfscl_deleggetmodtime(vp, &ap->a_vap->va_mtime);
                        return (0);
                }
        }

        error = nfsrpc_getattr(vp, ap->a_cred, td, &nfsva);
        if (error == 0)
                error = nfscl_loadattrcache(&vp, &nfsva, vap, 0, 0);
        if (!error) {
                /*
                 * Get the local modify time for the case of a write
                 * delegation.
                 */
                nfscl_deleggetmodtime(vp, &vap->va_mtime);
        } else if (NFS_ISV4(vp)) {
                error = nfscl_maperr(td, error, (uid_t)0, (gid_t)0);
        }
        return (error);
}

/*
 * nfs setattr call.
 */
static int
nfs_setattr(struct vop_setattr_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct nfsnode *np = VTONFS(vp);
        struct thread *td = curthread;  /* XXX */
        struct vattr *vap = ap->a_vap;
        int error = 0;
        u_quad_t tsize;
        struct timespec ts;
        struct nfsmount *nmp;

#ifndef nolint
        tsize = (u_quad_t)0;
#endif

        /*
         * Only setting of UF_ARCHIVE, UF_HIDDEN and UF_SYSTEM are supported and
         * only for NFSv4 servers that support them.
         */
        nmp = VFSTONFS(vp->v_mount);
        if (vap->va_flags != VNOVAL && (!NFSHASNFSV4(nmp) ||
            (vap->va_flags & ~(UF_ARCHIVE | UF_HIDDEN | UF_SYSTEM)) != 0 ||
            ((vap->va_flags & UF_ARCHIVE) != 0 &&
             !NFSISSET_ATTRBIT(&np->n_vattr.na_suppattr, NFSATTRBIT_ARCHIVE)) ||
            ((vap->va_flags & UF_HIDDEN) != 0 &&
             !NFSISSET_ATTRBIT(&np->n_vattr.na_suppattr, NFSATTRBIT_HIDDEN)) ||
            ((vap->va_flags & UF_SYSTEM) != 0 &&
             !NFSISSET_ATTRBIT(&np->n_vattr.na_suppattr, NFSATTRBIT_SYSTEM))))
                return (EOPNOTSUPP);

        /*
         * Disallow write attempts if the filesystem is mounted read-only.
         */
        if ((vap->va_flags != (u_long)VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
            vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
            vap->va_mtime.tv_sec != VNOVAL ||
            vap->va_birthtime.tv_sec != VNOVAL ||
            vap->va_mode != (mode_t)VNOVAL) &&
            (vp->v_mount->mnt_flag & MNT_RDONLY))
                return (EROFS);
        if (vap->va_size != VNOVAL) {
                switch (vp->v_type) {
                case VDIR:
                        return (EISDIR);
                case VCHR:
                case VBLK:
                case VSOCK:
                case VFIFO:
                        if (vap->va_mtime.tv_sec == VNOVAL &&
                            vap->va_atime.tv_sec == VNOVAL &&
                            vap->va_birthtime.tv_sec == VNOVAL &&
                            vap->va_mode == (mode_t)VNOVAL &&
                            vap->va_uid == (uid_t)VNOVAL &&
                            vap->va_gid == (gid_t)VNOVAL)
                                return (0);             
                        vap->va_size = VNOVAL;
                        break;
                default:
                        /*
                         * Disallow write attempts if the filesystem is
                         * mounted read-only.
                         */
                        if (vp->v_mount->mnt_flag & MNT_RDONLY)
                                return (EROFS);
                        /*
                         *  We run vnode_pager_setsize() early (why?),
                         * we must set np->n_size now to avoid vinvalbuf
                         * V_SAVE races that might setsize a lower
                         * value.
                         */
                        NFSLOCKNODE(np);
                        tsize = np->n_size;
                        NFSUNLOCKNODE(np);
                        error = ncl_meta_setsize(vp, td, vap->va_size);
                        NFSLOCKNODE(np);
                        if (np->n_flag & NMODIFIED) {
                            tsize = np->n_size;
                            NFSUNLOCKNODE(np);
                            error = ncl_vinvalbuf(vp, vap->va_size == 0 ?
                                0 : V_SAVE, td, 1);
                            if (error != 0) {
                                    vnode_pager_setsize(vp, tsize);
                                    return (error);
                            }
                            /*
                             * Call nfscl_delegmodtime() to set the modify time
                             * locally, as required.
                             */
                            nfscl_delegmodtime(vp, NULL);
                        } else
                            NFSUNLOCKNODE(np);
                        /*
                         * np->n_size has already been set to vap->va_size
                         * in ncl_meta_setsize(). We must set it again since
                         * nfs_loadattrcache() could be called through
                         * ncl_meta_setsize() and could modify np->n_size.
                         */
                        NFSLOCKNODE(np);
                        np->n_vattr.na_size = np->n_size = vap->va_size;
                        NFSUNLOCKNODE(np);
                }
        } else {
                NFSLOCKNODE(np);
                if ((vap->va_mtime.tv_sec != VNOVAL || vap->va_atime.tv_sec != VNOVAL) && 
                    (np->n_flag & NMODIFIED) && vp->v_type == VREG) {
                        NFSUNLOCKNODE(np);
                        error = ncl_vinvalbuf(vp, V_SAVE, td, 1);
                        if (error == EINTR || error == EIO)
                                return (error);
                } else
                        NFSUNLOCKNODE(np);
        }
        error = nfs_setattrrpc(vp, vap, ap->a_cred, td);
        if (vap->va_size != VNOVAL) {
                if (error == 0) {
                        nanouptime(&ts);
                        NFSLOCKNODE(np);
                        np->n_localmodtime = ts;
                        NFSUNLOCKNODE(np);
                } else {
                        NFSLOCKNODE(np);
                        np->n_size = np->n_vattr.na_size = tsize;
                        vnode_pager_setsize(vp, tsize);
                        NFSUNLOCKNODE(np);
                }
        }
        if (vap->va_mtime.tv_sec != VNOVAL && error == 0)
                nfscl_delegmodtime(vp, &vap->va_mtime);
        return (error);
}

/*
 * Do an nfs setattr rpc.
 */
static int
nfs_setattrrpc(struct vnode *vp, struct vattr *vap, struct ucred *cred,
    struct thread *td)
{
        struct nfsnode *np = VTONFS(vp);
        int error, ret, attrflag, i;
        struct nfsvattr nfsva;

        if (NFS_ISV34(vp)) {
                NFSLOCKNODE(np);
                for (i = 0; i < NFS_ACCESSCACHESIZE; i++)
                        np->n_accesscache[i].stamp = 0;
                np->n_flag |= NDELEGMOD;
                NFSUNLOCKNODE(np);
                KDTRACE_NFS_ACCESSCACHE_FLUSH_DONE(vp);
        }
        error = nfsrpc_setattr(vp, vap, NULL, 0, cred, td, &nfsva, &attrflag);
        if (attrflag) {
                ret = nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
                if (ret && !error)
                        error = ret;
        }
        if (error && NFS_ISV4(vp))
                error = nfscl_maperr(td, error, vap->va_uid, vap->va_gid);
        return (error);
}

/*
 * Get a named attribute directory for the vnode.
 */
static int
nfs_get_namedattrdir(struct vnode *vp, struct componentname *cnp,
    struct vnode **vpp)
{
        struct nfsfh *nfhp;
        struct nfsnode *np;
        struct vnode *newvp;
        struct nfsvattr nfsva;
        int attrflag, error;

        attrflag = 0;
        *vpp = NULL;
        np = VTONFS(vp);
        error = nfsrpc_openattr(VFSTONFS(vp->v_mount), vp, np->n_fhp->nfh_fh,
            np->n_fhp->nfh_len, (cnp->cn_flags & CREATENAMED),
            cnp->cn_cred, curthread, &nfsva, &nfhp, &attrflag);
        if (error == NFSERR_NOTSUPP)
                error = ENOATTR;
        if (error == 0)
                error = nfscl_nget(vp->v_mount, vp, nfhp, cnp, curthread, &np,
                    cnp->cn_lkflags);
        if (error != 0)
                return (error);
        newvp = NFSTOV(np);
        vn_irflag_set_cond(newvp, VIRF_NAMEDDIR);
        if (attrflag != 0)
                (void)nfscl_loadattrcache(&newvp, &nfsva, NULL, 0, 1);
        *vpp = newvp;
        return (0);
}

/*
 * nfs lookup call, one step at a time...
 * First look in cache
 * If not found, unlock the directory nfsnode and do the rpc
 */
static int
nfs_lookup(struct vop_lookup_args *ap)
{
        struct componentname *cnp = ap->a_cnp;
        struct vnode *dvp = ap->a_dvp;
        struct vnode **vpp = ap->a_vpp;
        struct mount *mp = dvp->v_mount;
        uint64_t flags = cnp->cn_flags;
        struct vnode *newvp;
        struct nfsmount *nmp;
        struct nfsnode *np, *newnp;
        int error = 0, attrflag, dattrflag, ltype, ncticks;
        struct thread *td = curthread;
        struct nfsfh *nfhp;
        struct nfsvattr dnfsva, nfsva;
        struct vattr vattr;
        struct timespec nctime, ts;
        uint32_t openmode;
        bool is_nameddir, needs_nameddir, opennamed;

        dattrflag = 0;
        *vpp = NULL;
        nmp = VFSTONFS(mp);
        opennamed = (flags & (OPENNAMED | ISLASTCN)) == (OPENNAMED | ISLASTCN);
        if (opennamed && (!NFSHASNFSV4(nmp) || !NFSHASNFSV4N(nmp)))
                return (ENOATTR);
        is_nameddir = (vn_irflag_read(dvp) & VIRF_NAMEDDIR) != 0;
        if ((is_nameddir && (flags & ISLASTCN) == 0 && (cnp->cn_namelen > 1 ||
            *cnp->cn_nameptr != '.')) ||
            (opennamed && !is_nameddir && (flags & ISDOTDOT) != 0))
                return (ENOATTR);
        if ((flags & ISLASTCN) && (mp->mnt_flag & MNT_RDONLY) &&
            (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
                return (EROFS);
        np = VTONFS(dvp);

        needs_nameddir = false;
        if (opennamed || is_nameddir) {
                cnp->cn_flags &= ~MAKEENTRY;
                if (!is_nameddir)
                        needs_nameddir = true;
        }

        /*
         * If the named attribute directory is needed, acquire it now.
         */
        newvp = NULL;
        if (needs_nameddir) {
                KASSERT(np->n_v4 == NULL, ("nfs_lookup: O_NAMEDATTR when"
                    " n_v4 not NULL"));
                error = nfs_get_namedattrdir(dvp, cnp, &newvp);
                if (error != 0)
                        goto handle_error;
                if (cnp->cn_namelen == 1 && *cnp->cn_nameptr == '.') {
                        *vpp = newvp;
                        return (0);
                }
                dvp = newvp;
                np = VTONFS(dvp);
                newvp = NULL;
        } else if (opennamed && cnp->cn_namelen == 1 &&
            *cnp->cn_nameptr == '.') {
                vref(dvp);
                *vpp = dvp;
                return (0);
        }

        if (dvp->v_type != VDIR)
                return (ENOTDIR);

        /* For NFSv4, wait until any remove is done. */
        NFSLOCKNODE(np);
        while (NFSHASNFSV4(nmp) && (np->n_flag & NREMOVEINPROG)) {
                np->n_flag |= NREMOVEWANT;
                (void) msleep((caddr_t)np, &np->n_mtx, PZERO, "nfslkup", 0);
        }
        NFSUNLOCKNODE(np);

        error = vn_dir_check_exec(dvp, cnp);
        if (error != 0)
                return (error);

        if (!opennamed && !is_nameddir) {
                error = cache_lookup(dvp, vpp, cnp, &nctime, &ncticks);
                if (error > 0 && error != ENOENT)
                        return (error);
                if (error == -1) {
                        /*
                         * Lookups of "." are special and always return the
                         * current directory.  cache_lookup() already handles
                         * associated locking bookkeeping, etc.
                         */
                        if (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.') {
                                return (0);
                        }

                        /*
                         * We only accept a positive hit in the cache if the
                         * change time of the file matches our cached copy.
                         * Otherwise, we discard the cache entry and fallback
                         * to doing a lookup RPC.  We also only trust cache
                         * entries for less than nm_nametimeo seconds.
                         *
                         * To better handle stale file handles and attributes,
                         * clear the attribute cache of this node if it is a
                         * leaf component, part of an open() call, and not
                         * locally modified before fetching the attributes.
                         * This should allow stale file handles to be detected
                         * here where we can fall back to a LOOKUP RPC to
                         * recover rather than having nfs_open() detect the
                         * stale file handle and failing open(2) with ESTALE.
                         */
                        newvp = *vpp;
                        newnp = VTONFS(newvp);
                        if (!(nmp->nm_flag & NFSMNT_NOCTO) &&
                            (flags & (ISLASTCN | ISOPEN)) ==
                             (ISLASTCN | ISOPEN) &&
                            !(newnp->n_flag & NMODIFIED)) {
                                NFSLOCKNODE(newnp);
                                newnp->n_attrstamp = 0;
                                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(newvp);
                                NFSUNLOCKNODE(newnp);
                        }
                        if (nfscl_nodeleg(newvp, 0) == 0 ||
                            ((u_int)(ticks - ncticks) <
                            (nmp->nm_nametimeo * hz) &&
                            VOP_GETATTR(newvp, &vattr, cnp->cn_cred) == 0 &&
                            timespeccmp(&vattr.va_ctime, &nctime, ==))) {
                                NFSINCRGLOBAL(nfsstatsv1.lookupcache_hits);
                                return (0);
                        }
                        cache_purge(newvp);
                        if (dvp != newvp)
                                vput(newvp);
                        else
                                vrele(newvp);
                        *vpp = NULL;
                } else if (error == ENOENT) {
                        if (VN_IS_DOOMED(dvp))
                                return (ENOENT);
                        /*
                         * We only accept a negative hit in the cache if the
                         * modification time of the parent directory matches
                         * the cached copy in the name cache entry.
                         * Otherwise, we discard all of the negative cache
                         * entries for this directory.  We also only trust
                         * negative cache entries for up to nm_negnametimeo
                         * seconds.
                         */
                        if ((u_int)(ticks - ncticks) <
                            (nmp->nm_negnametimeo * hz) &&
                            VOP_GETATTR(dvp, &vattr, cnp->cn_cred) == 0 &&
                            timespeccmp(&vattr.va_mtime, &nctime, ==)) {
                                NFSINCRGLOBAL(nfsstatsv1.lookupcache_hits);
                                return (ENOENT);
                        }
                        cache_purge_negative(dvp);
                }
        }

        openmode = 0;
#if 0
        /*
         * The use of LookupOpen breaks some builds.  It is disabled
         * until that is fixed.
         */
        /*
         * If this an NFSv4.1/4.2 mount using the "oneopenown" mount
         * option, it is possible to do the Open operation in the same
         * compound as Lookup, so long as delegations are not being
         * issued.  This saves doing a separate RPC for Open.
         * For pnfs, do not do this, since the Open+LayoutGet will
         * be needed as a separate RPC.
         */
        NFSLOCKMNT(nmp);
        if (NFSHASNFSV4N(nmp) && NFSHASONEOPENOWN(nmp) && !NFSHASPNFS(nmp) &&
            (nmp->nm_privflag & NFSMNTP_DELEGISSUED) == 0 &&
            (!NFSMNT_RDONLY(mp) || (flags & OPENWRITE) == 0) &&
            (flags & (ISLASTCN | ISOPEN | OPENNAMED))) == (ISLASTCN | ISOPEN)) {
                if ((flags & OPENREAD) != 0)
                        openmode |= NFSV4OPEN_ACCESSREAD;
                if ((flags & OPENWRITE) != 0)
                        openmode |= NFSV4OPEN_ACCESSWRITE;
        }
        NFSUNLOCKMNT(nmp);
#endif

        newvp = NULL;
        NFSINCRGLOBAL(nfsstatsv1.lookupcache_misses);
        nanouptime(&ts);
        error = nfsrpc_lookup(dvp, cnp->cn_nameptr, cnp->cn_namelen,
            cnp->cn_cred, td, &dnfsva, &nfsva, &nfhp, &attrflag, &dattrflag,
            openmode);
        if (dattrflag)
                (void) nfscl_loadattrcache(&dvp, &dnfsva, NULL, 0, 1);
        if (needs_nameddir) {
                vput(dvp);
                dvp = ap->a_dvp;
        }
handle_error:
        if (error) {
                if (newvp != NULL) {
                        vput(newvp);
                        *vpp = NULL;
                }

                if (error != ENOENT) {
                        if (NFS_ISV4(dvp))
                                error = nfscl_maperr(td, error,
                                    (uid_t)0, (gid_t)0);
                        return (error);
                }

                /* The requested file was not found. */
                if ((cnp->cn_nameiop == CREATE ||
                     cnp->cn_nameiop == RENAME) &&
                    (flags & ISLASTCN)) {
                        /*
                         * XXX: UFS does a full VOP_ACCESS(dvp,
                         * VWRITE) here instead of just checking
                         * MNT_RDONLY.
                         */
                        if (mp->mnt_flag & MNT_RDONLY)
                                return (EROFS);
                        return (EJUSTRETURN);
                }

                if ((cnp->cn_flags & MAKEENTRY) != 0 && dattrflag &&
                    !NFSHASCASEINSENSITIVE(nmp)) {
                        /*
                         * Cache the modification time of the parent
                         * directory from the post-op attributes in
                         * the name cache entry.  The negative cache
                         * entry will be ignored once the directory
                         * has changed.  Don't bother adding the entry
                         * if the directory has already changed.
                         */
                        NFSLOCKNODE(np);
                        if (timespeccmp(&np->n_vattr.na_mtime,
                            &dnfsva.na_mtime, ==)) {
                                NFSUNLOCKNODE(np);
                                cache_enter_time(dvp, NULL, cnp,
                                    &dnfsva.na_mtime, NULL);
                        } else
                                NFSUNLOCKNODE(np);
                }
                return (ENOENT);
        }

        /*
         * Handle RENAME case...
         */
        if (cnp->cn_nameiop == RENAME && (flags & ISLASTCN)) {
                if (NFS_CMPFH(np, nfhp->nfh_fh, nfhp->nfh_len)) {
                        free(nfhp, M_NFSFH);
                        return (EISDIR);
                }
                error = nfscl_nget(mp, dvp, nfhp, cnp, td, &np,
                    LK_EXCLUSIVE);
                if (error)
                        return (error);
                newvp = NFSTOV(np);
                /*
                 * If n_localmodtime >= time before RPC, then
                 * a file modification operation, such as
                 * VOP_SETATTR() of size, has occurred while
                 * the Lookup RPC and acquisition of the vnode
                 * happened.  As such, the attributes might
                 * be stale, with possibly an incorrect size.
                 */
                NFSLOCKNODE(np);
                if (timespecisset(&np->n_localmodtime) &&
                    timespeccmp(&np->n_localmodtime, &ts, >=)) {
                        NFSCL_DEBUG(4, "nfs_lookup: rename localmod "
                            "stale attributes\n");
                        attrflag = 0;
                }
                NFSUNLOCKNODE(np);
                if (attrflag)
                        (void) nfscl_loadattrcache(&newvp, &nfsva, NULL,
                            0, 1);
                *vpp = newvp;
                return (0);
        }

        if (flags & ISDOTDOT) {
                ltype = NFSVOPISLOCKED(dvp);
                error = vfs_busy(mp, MBF_NOWAIT);
                if (error != 0) {
                        vfs_ref(mp);
                        NFSVOPUNLOCK(dvp);
                        error = vfs_busy(mp, 0);
                        NFSVOPLOCK(dvp, ltype | LK_RETRY);
                        vfs_rel(mp);
                        if (error == 0 && VN_IS_DOOMED(dvp)) {
                                vfs_unbusy(mp);
                                error = ENOENT;
                        }
                        if (error != 0)
                                return (error);
                }
                NFSVOPUNLOCK(dvp);
                error = nfscl_nget(mp, dvp, nfhp, cnp, td, &np,
                    cnp->cn_lkflags);
                if (error == 0)
                        newvp = NFSTOV(np);
                vfs_unbusy(mp);
                if (newvp != dvp)
                        NFSVOPLOCK(dvp, ltype | LK_RETRY);
                if (VN_IS_DOOMED(dvp)) {
                        if (error == 0) {
                                if (newvp == dvp)
                                        vrele(newvp);
                                else
                                        vput(newvp);
                        }
                        error = ENOENT;
                }
                if (error != 0)
                        return (error);
                if (attrflag)
                        (void) nfscl_loadattrcache(&newvp, &nfsva, NULL,
                            0, 1);
        } else if (NFS_CMPFH(np, nfhp->nfh_fh, nfhp->nfh_len)) {
                free(nfhp, M_NFSFH);
                vref(dvp);
                newvp = dvp;
                if (attrflag)
                        (void) nfscl_loadattrcache(&newvp, &nfsva, NULL,
                            0, 1);
        } else {
                error = nfscl_nget(mp, dvp, nfhp, cnp, td, &np,
                    cnp->cn_lkflags);
                if (error)
                        return (error);
                newvp = NFSTOV(np);
                if (opennamed)
                        vn_irflag_set_cond(newvp, VIRF_NAMEDATTR);
                /*
                 * If n_localmodtime >= time before RPC, then
                 * a file modification operation, such as
                 * VOP_SETATTR() of size, has occurred while
                 * the Lookup RPC and acquisition of the vnode
                 * happened.  As such, the attributes might
                 * be stale, with possibly an incorrect size.
                 */
                NFSLOCKNODE(np);
                if (timespecisset(&np->n_localmodtime) &&
                    timespeccmp(&np->n_localmodtime, &ts, >=)) {
                        NFSCL_DEBUG(4, "nfs_lookup: localmod "
                            "stale attributes\n");
                        attrflag = 0;
                }
                NFSUNLOCKNODE(np);
                if (attrflag)
                        (void)nfscl_loadattrcache(&newvp, &nfsva, NULL,
                            0, 1);
                else if ((flags & (ISLASTCN | ISOPEN)) ==
                    (ISLASTCN | ISOPEN) &&
                    !(np->n_flag & NMODIFIED)) {                        
                        /*
                         * Flush the attribute cache when opening a
                         * leaf node to ensure that fresh attributes
                         * are fetched in nfs_open() since we did not
                         * fetch attributes from the LOOKUP reply.
                         */
                        NFSLOCKNODE(np);
                        np->n_attrstamp = 0;
                        KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(newvp);
                        NFSUNLOCKNODE(np);
                }
        }
        if ((cnp->cn_flags & MAKEENTRY) && dvp != newvp &&
            (cnp->cn_nameiop != DELETE || !(flags & ISLASTCN)) &&
            attrflag != 0 && (newvp->v_type != VDIR || dattrflag != 0))
                cache_enter_time(dvp, newvp, cnp, &nfsva.na_ctime,
                    newvp->v_type != VDIR ? NULL : &dnfsva.na_ctime);
        *vpp = newvp;
        return (0);
}

/*
 * nfs read call.
 * Just call ncl_bioread() to do the work.
 */
static int
nfs_read(struct vop_read_args *ap)
{
        struct vnode *vp = ap->a_vp;

        switch (vp->v_type) {
        case VREG:
                return (ncl_bioread(vp, ap->a_uio, ap->a_ioflag, ap->a_cred));
        case VDIR:
                return (EISDIR);
        default:
                return (EOPNOTSUPP);
        }
}

/*
 * nfs readlink call
 */
static int
nfs_readlink(struct vop_readlink_args *ap)
{
        struct vnode *vp = ap->a_vp;

        if (vp->v_type != VLNK)
                return (EINVAL);
        return (ncl_bioread(vp, ap->a_uio, 0, ap->a_cred));
}

/*
 * Do a readlink rpc.
 * Called by ncl_doio() from below the buffer cache.
 */
int
ncl_readlinkrpc(struct vnode *vp, struct uio *uiop, struct ucred *cred)
{
        int error, ret, attrflag;
        struct nfsvattr nfsva;

        error = nfsrpc_readlink(vp, uiop, cred, uiop->uio_td, &nfsva,
            &attrflag);
        if (attrflag) {
                ret = nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
                if (ret && !error)
                        error = ret;
        }
        if (error && NFS_ISV4(vp))
                error = nfscl_maperr(uiop->uio_td, error, (uid_t)0, (gid_t)0);
        return (error);
}

/*
 * nfs read rpc call
 * Ditto above
 */
int
ncl_readrpc(struct vnode *vp, struct uio *uiop, struct ucred *cred)
{
        int error, ret, attrflag;
        struct nfsvattr nfsva;
        struct nfsmount *nmp;

        nmp = VFSTONFS(vp->v_mount);
        error = EIO;
        attrflag = 0;
        if (NFSHASPNFS(nmp))
                error = nfscl_doiods(vp, uiop, NULL, NULL,
                    NFSV4OPEN_ACCESSREAD, 0, cred, uiop->uio_td);
        NFSCL_DEBUG(4, "readrpc: aft doiods=%d\n", error);
        if (error != 0 && error != EFAULT)
                error = nfsrpc_read(vp, uiop, cred, uiop->uio_td, &nfsva,
                    &attrflag);
        if (attrflag) {
                ret = nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
                if (ret && !error)
                        error = ret;
        }
        if (error && NFS_ISV4(vp))
                error = nfscl_maperr(uiop->uio_td, error, (uid_t)0, (gid_t)0);
        return (error);
}

/*
 * nfs write call
 */
int
ncl_writerpc(struct vnode *vp, struct uio *uiop, struct ucred *cred,
    int *iomode, int *must_commit, int called_from_strategy, int ioflag)
{
        struct nfsvattr nfsva;
        int error, attrflag, ret;
        struct nfsmount *nmp;

        nmp = VFSTONFS(vp->v_mount);
        error = EIO;
        attrflag = 0;
        if (NFSHASPNFS(nmp))
                error = nfscl_doiods(vp, uiop, iomode, must_commit,
                    NFSV4OPEN_ACCESSWRITE, 0, cred, uiop->uio_td);
        NFSCL_DEBUG(4, "writerpc: aft doiods=%d\n", error);
        if (error != 0 && error != EFAULT)
                error = nfsrpc_write(vp, uiop, iomode, must_commit, cred,
                    uiop->uio_td, &nfsva, &attrflag, called_from_strategy,
                    ioflag);
        if (attrflag) {
                if (VTONFS(vp)->n_flag & ND_NFSV4)
                        ret = nfscl_loadattrcache(&vp, &nfsva, NULL, 1, 1);
                else
                        ret = nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
                if (ret && !error)
                        error = ret;
        }
        if (DOINGASYNC(vp))
                *iomode = NFSWRITE_FILESYNC;
        if (error && NFS_ISV4(vp))
                error = nfscl_maperr(uiop->uio_td, error, (uid_t)0, (gid_t)0);
        return (error);
}

/*
 * nfs mknod rpc
 * For NFS v2 this is a kludge. Use a create rpc but with the IFMT bits of the
 * mode set to specify the file type and the size field for rdev.
 */
static int
nfs_mknodrpc(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp,
    struct vattr *vap)
{
        struct nfsvattr nfsva, dnfsva;
        struct vnode *newvp = NULL;
        struct nfsnode *np = NULL, *dnp;
        struct nfsfh *nfhp;
        struct vattr vattr;
        int error = 0, attrflag, dattrflag;
        u_int32_t rdev;

        if (VATTR_ISDEV(vap))
                rdev = vap->va_rdev;
        else if (vap->va_type == VFIFO || vap->va_type == VSOCK)
                rdev = 0xffffffff;
        else
                return (EOPNOTSUPP);
        if ((error = VOP_GETATTR(dvp, &vattr, cnp->cn_cred)))
                return (error);
        error = nfsrpc_mknod(dvp, cnp->cn_nameptr, cnp->cn_namelen, vap,
            rdev, vap->va_type, cnp->cn_cred, curthread, &dnfsva,
            &nfsva, &nfhp, &attrflag, &dattrflag);
        if (!error) {
                if (!nfhp)
                        (void) nfsrpc_lookup(dvp, cnp->cn_nameptr,
                            cnp->cn_namelen, cnp->cn_cred, curthread,
                            &dnfsva, &nfsva, &nfhp, &attrflag, &dattrflag, 0);
                if (nfhp)
                        error = nfscl_nget(dvp->v_mount, dvp, nfhp, cnp,
                            curthread, &np, LK_EXCLUSIVE);
        }
        if (dattrflag)
                (void) nfscl_loadattrcache(&dvp, &dnfsva, NULL, 0, 1);
        if (!error) {
                newvp = NFSTOV(np);
                if (attrflag != 0) {
                        error = nfscl_loadattrcache(&newvp, &nfsva, NULL, 0, 1);
                        if (error != 0)
                                vput(newvp);
                }
        }
        if (!error) {
                *vpp = newvp;
        } else if (NFS_ISV4(dvp)) {
                error = nfscl_maperr(curthread, error, vap->va_uid,
                    vap->va_gid);
        }
        dnp = VTONFS(dvp);
        NFSLOCKNODE(dnp);
        dnp->n_flag |= NMODIFIED;
        if (!dattrflag) {
                dnp->n_attrstamp = 0;
                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(dvp);
        }
        NFSUNLOCKNODE(dnp);
        return (error);
}

/*
 * nfs mknod vop
 * just call nfs_mknodrpc() to do the work.
 */
/* ARGSUSED */
static int
nfs_mknod(struct vop_mknod_args *ap)
{
        return (nfs_mknodrpc(ap->a_dvp, ap->a_vpp, ap->a_cnp, ap->a_vap));
}

static struct mtx nfs_cverf_mtx;
MTX_SYSINIT(nfs_cverf_mtx, &nfs_cverf_mtx, "NFS create verifier mutex",
    MTX_DEF);

static nfsquad_t
nfs_get_cverf(void)
{
        static nfsquad_t cverf;
        nfsquad_t ret;
        static int cverf_initialized = 0;

        mtx_lock(&nfs_cverf_mtx);
        if (cverf_initialized == 0) {
                cverf.lval[0] = arc4random();
                cverf.lval[1] = arc4random();
                cverf_initialized = 1;
        } else
                cverf.qval++;
        ret = cverf;
        mtx_unlock(&nfs_cverf_mtx);

        return (ret);
}

/*
 * nfs file create call
 */
static int
nfs_create(struct vop_create_args *ap)
{
        struct vnode *dvp = ap->a_dvp;
        struct vattr *vap = ap->a_vap;
        struct componentname *cnp = ap->a_cnp;
        struct nfsnode *np = NULL, *dnp;
        struct vnode *newvp = NULL;
        struct nfsmount *nmp;
        struct nfsvattr dnfsva, nfsva;
        struct nfsfh *nfhp;
        nfsquad_t cverf;
        int error = 0, attrflag, dattrflag, fmode = 0;
        struct vattr vattr;
        bool is_nameddir, needs_nameddir, opennamed;

        /*
         * Oops, not for me..
         */
        if (vap->va_type == VSOCK)
                return (nfs_mknodrpc(dvp, ap->a_vpp, cnp, vap));

        if ((error = VOP_GETATTR(dvp, &vattr, cnp->cn_cred)))
                return (error);
        if (vap->va_vaflags & VA_EXCLUSIVE)
                fmode |= O_EXCL;
        dnp = VTONFS(dvp);
        nmp = VFSTONFS(dvp->v_mount);
        needs_nameddir = false;
        if (NFSHASNFSV4(nmp) && NFSHASNFSV4N(nmp)) {
                opennamed = (cnp->cn_flags & (OPENNAMED | ISLASTCN)) ==
                    (OPENNAMED | ISLASTCN);
                is_nameddir = (vn_irflag_read(dvp) & VIRF_NAMEDDIR) != 0;
                if (opennamed || is_nameddir) {
                        cnp->cn_flags &= ~MAKEENTRY;
                        if (!is_nameddir)
                                needs_nameddir = true;
                }
        }

        /*
         * If the named attribute directory is needed, acquire it now.
         */
        if (needs_nameddir) {
                KASSERT(dnp->n_v4 == NULL, ("nfs_create: O_NAMEDATTR when"
                    " n_v4 not NULL"));
                error = nfs_get_namedattrdir(dvp, cnp, &newvp);
                if (error != 0)
                        return (error);
                dvp = newvp;
                dnp = VTONFS(dvp);
                newvp = NULL;
        }

again:
        /* For NFSv4, wait until any remove is done. */
        NFSLOCKNODE(dnp);
        while (NFSHASNFSV4(nmp) && (dnp->n_flag & NREMOVEINPROG)) {
                dnp->n_flag |= NREMOVEWANT;
                (void) msleep((caddr_t)dnp, &dnp->n_mtx, PZERO, "nfscrt", 0);
        }
        NFSUNLOCKNODE(dnp);

        cverf = nfs_get_cverf();
        error = nfsrpc_create(dvp, cnp->cn_nameptr, cnp->cn_namelen,
            vap, cverf, fmode, cnp->cn_cred, curthread, &dnfsva, &nfsva,
            &nfhp, &attrflag, &dattrflag);
        if (!error) {
                if (nfhp == NULL)
                        (void) nfsrpc_lookup(dvp, cnp->cn_nameptr,
                            cnp->cn_namelen, cnp->cn_cred, curthread,
                            &dnfsva, &nfsva, &nfhp, &attrflag, &dattrflag, 0);
                if (nfhp != NULL)
                        error = nfscl_nget(dvp->v_mount, dvp, nfhp, cnp,
                            curthread, &np, LK_EXCLUSIVE);
        }
        if (dattrflag)
                (void) nfscl_loadattrcache(&dvp, &dnfsva, NULL, 0, 1);
        if (!error) {
                newvp = NFSTOV(np);
                if (attrflag == 0)
                        error = nfsrpc_getattr(newvp, cnp->cn_cred, curthread,
                            &nfsva);
                if (error == 0)
                        error = nfscl_loadattrcache(&newvp, &nfsva, NULL, 0, 1);
        }
        if (error) {
                if (newvp != NULL) {
                        vput(newvp);
                        newvp = NULL;
                }
                if (NFS_ISV34(dvp) && (fmode & O_EXCL) &&
                    error == NFSERR_NOTSUPP) {
                        fmode &= ~O_EXCL;
                        goto again;
                }
        } else if (NFS_ISV34(dvp) && (fmode & O_EXCL)) {
                if (nfscl_checksattr(vap, &nfsva)) {
                        error = nfsrpc_setattr(newvp, vap, NULL, 0,
                            cnp->cn_cred, curthread, &nfsva, &attrflag);
                        if (error && (vap->va_uid != (uid_t)VNOVAL ||
                            vap->va_gid != (gid_t)VNOVAL)) {
                                /* try again without setting uid/gid */
                                vap->va_uid = (uid_t)VNOVAL;
                                vap->va_gid = (uid_t)VNOVAL;
                                error = nfsrpc_setattr(newvp, vap, NULL, 0,
                                    cnp->cn_cred, curthread, &nfsva, &attrflag);
                        }
                        if (attrflag)
                                (void) nfscl_loadattrcache(&newvp, &nfsva, NULL,
                                    0, 1);
                        if (error != 0)
                                vput(newvp);
                }
        }
        if (!error) {
                if ((cnp->cn_flags & MAKEENTRY) && attrflag) {
                        if (dvp != newvp)
                                cache_enter_time(dvp, newvp, cnp,
                                    &nfsva.na_ctime, NULL);
                        else
                                printf("nfs_create: bogus NFS server returned "
                                    "the directory as the new file object\n");
                }
                *ap->a_vpp = newvp;
        } else if (NFS_ISV4(dvp)) {
                error = nfscl_maperr(curthread, error, vap->va_uid,
                    vap->va_gid);
        }
        NFSLOCKNODE(dnp);
        dnp->n_flag |= NMODIFIED;
        if (!dattrflag) {
                dnp->n_attrstamp = 0;
                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(dvp);
        }
        NFSUNLOCKNODE(dnp);
        if (needs_nameddir)
                vput(dvp);
        return (error);
}

/*
 * nfs file remove call
 * To try and make nfs semantics closer to ufs semantics, a file that has
 * other processes using the vnode is renamed instead of removed and then
 * removed later on the last close.
 * - If v_usecount > 1
 *        If a rename is not already in the works
 *           call nfs_sillyrename() to set it up
 *     else
 *        do the remove rpc
 */
static int
nfs_remove(struct vop_remove_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct vnode *dvp = ap->a_dvp;
        struct componentname *cnp = ap->a_cnp;
        struct nfsnode *np = VTONFS(vp);
        int error = 0;
        struct vattr vattr;
        struct nfsmount *nmp;

        KASSERT(vrefcnt(vp) > 0, ("nfs_remove: bad v_usecount"));
        if (vp->v_type == VDIR)
                error = EPERM;
        else if (vrefcnt(vp) == 1 || (np->n_sillyrename &&
            VOP_GETATTR(vp, &vattr, cnp->cn_cred) == 0 &&
            vattr.va_nlink > 1)) {
                nmp = VFSTONFS(vp->v_mount);
                /*
                 * Purge the name cache so that the chance of a lookup for
                 * the name succeeding while the remove is in progress is
                 * minimized. Without node locking it can still happen, such
                 * that an I/O op returns ESTALE, but since you get this if
                 * another host removes the file..
                 */
                cache_purge(vp);
                /*
                 * throw away biocache buffers, mainly to avoid
                 * unnecessary delayed writes later.
                 * Flushing here would be more correct for the case
                 * where nfs_close() did not do a flush.  However, it
                 * could be a large performance hit for some servers
                 * and only matters when the file name being removed is
                 * one of multiple hard links.
                 */
                if (!NFSHASNFSV4(nmp) || !NFSHASNFSV4N(nmp) ||
                    (nmp->nm_flag & NFSMNT_NOCTO) == 0)
                        error = ncl_vinvalbuf(vp, 0, curthread, 1);
                if (error != EINTR && error != EIO)
                        /* Do the rpc */
                        error = nfs_removerpc(dvp, vp, cnp->cn_nameptr,
                            cnp->cn_namelen, cnp->cn_cred, curthread, false);
                /*
                 * Kludge City: If the first reply to the remove rpc is lost..
                 *   the reply to the retransmitted request will be ENOENT
                 *   since the file was in fact removed
                 *   Therefore, we cheat and return success.
                 */
                if (error == ENOENT)
                        error = 0;
        } else if (!np->n_sillyrename)
                error = nfs_sillyrename(dvp, vp, cnp);
        NFSLOCKNODE(np);
        np->n_attrstamp = 0;
        NFSUNLOCKNODE(np);
        KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
        return (error);
}

/*
 * nfs file remove rpc called from nfs_inactive
 */
int
ncl_removeit(struct sillyrename *sp, struct vnode *vp)
{
        /*
         * Make sure that the directory vnode is still valid.
         * XXX we should lock sp->s_dvp here.
         */
        if (sp->s_dvp->v_type == VBAD)
                return (0);
        return (nfs_removerpc(sp->s_dvp, vp, sp->s_name, sp->s_namlen,
            sp->s_cred, NULL, true));
}

/*
 * Handle the nfsremove_status reply from the RPC function.
 */
static void
nfs_removestatus(struct vnode *vp, nfsremove_status file_status,
    bool silly, struct thread *td)
{

        switch (file_status) {
        case NLINK_ZERO:
                /* Get rid of any delegation. */
                nfscl_delegreturnvp(vp, false, td);
                /* FALLTHROUGH */
        case DELETED:
                /* Throw away buffer cache blocks. */
                (void)ncl_vinvalbuf(vp, 0, td, 1);
                break;
        case VALID:
                /* Nothing to do, delegation is still ok. */
                break;
        default:
                break;
        }
}

/*
 * Nfs remove rpc, called from nfs_remove() and ncl_removeit().
 */
static int
nfs_removerpc(struct vnode *dvp, struct vnode *vp, char *name,
    int namelen, struct ucred *cred, struct thread *td, bool silly)
{
        struct nfsvattr dnfsva, nfsva;
        struct nfsnode *dnp = VTONFS(dvp);
        struct nfsmount *nmp;
        int attrflag, error = 0, dattrflag;
        nfsremove_status file_status;

        nmp = VFSTONFS(dvp->v_mount);
        NFSLOCKNODE(dnp);
        dnp->n_flag |= NREMOVEINPROG;
        NFSUNLOCKNODE(dnp);
        error = nfsrpc_remove(dvp, name, namelen, vp, &nfsva, &attrflag,
            &file_status, &dnfsva, &dattrflag, cred, td);
        NFSLOCKNODE(dnp);
        if ((dnp->n_flag & NREMOVEWANT)) {
                dnp->n_flag &= ~(NREMOVEWANT | NREMOVEINPROG);
                NFSUNLOCKNODE(dnp);
                wakeup((caddr_t)dnp);
        } else {
                dnp->n_flag &= ~NREMOVEINPROG;
                NFSUNLOCKNODE(dnp);
        }

        if (NFSHASNFSV4(nmp) && NFSHASNFSV4N(nmp)) {
                if (file_status != DELETED && attrflag != 0)
                        (void)nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
                if ((nmp->nm_flag & NFSMNT_NOCTO) != 0)
                        nfs_removestatus(vp, file_status, silly, td);
        }

        if (dattrflag != 0)
                (void) nfscl_loadattrcache(&dvp, &dnfsva, NULL, 0, 1);
        NFSLOCKNODE(dnp);
        dnp->n_flag |= NMODIFIED;
        if (dattrflag == 0) {
                dnp->n_attrstamp = 0;
                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(dvp);
        }
        NFSUNLOCKNODE(dnp);
        if (error && NFS_ISV4(dvp))
                error = nfscl_maperr(td, error, (uid_t)0, (gid_t)0);
        return (error);
}

/*
 * nfs file rename call
 */
static int
nfs_rename(struct vop_rename_args *ap)
{
        struct vnode *fvp = ap->a_fvp;
        struct vnode *tvp = ap->a_tvp;
        struct vnode *fdvp = ap->a_fdvp;
        struct vnode *tdvp = ap->a_tdvp;
        struct componentname *tcnp = ap->a_tcnp;
        struct componentname *fcnp = ap->a_fcnp;
        struct nfsnode *fnp = VTONFS(ap->a_fvp);
        struct nfsnode *tdnp = VTONFS(ap->a_tdvp);
        struct nfsv4node *newv4 = NULL;
        struct nfsmount *nmp;
        int error;

        /* Check for cross-device rename */
        if ((fvp->v_mount != tdvp->v_mount) ||
            (tvp && (fvp->v_mount != tvp->v_mount))) {
                error = EXDEV;
                goto out;
        }

        if (ap->a_flags != 0) {
                error = EOPNOTSUPP;
                goto out;
        }

        nmp = VFSTONFS(fvp->v_mount);

        if (fvp == tvp) {
                printf("nfs_rename: fvp == tvp (can't happen)\n");
                error = 0;
                goto out;
        }
        if ((error = NFSVOPLOCK(fvp, LK_EXCLUSIVE)) != 0)
                goto out;

        /*
         * For case insensitive file systems, there may be multiple
         * names cached for the one name being rename'd, so purge
         * all names from the cache.
         */
        if (NFSHASCASEINSENSITIVE(nmp))
                cache_purge(fvp);

        /*
         * We have to flush B_DELWRI data prior to renaming
         * the file.  If we don't, the delayed-write buffers
         * can be flushed out later after the file has gone stale
         * under NFSV3.  NFSV2 does not have this problem because
         * ( as far as I can tell ) it flushes dirty buffers more
         * often.
         * 
         * Skip the rename operation if the fsync fails, this can happen
         * due to the server's volume being full, when we pushed out data
         * that was written back to our cache earlier. Not checking for
         * this condition can result in potential (silent) data loss.
         */
        if ((nmp->nm_flag & NFSMNT_NOCTO) == 0 || !NFSHASNFSV4(nmp) ||
            !NFSHASNFSV4N(nmp) || nfscl_mustflush(fvp) != 0)
                error = VOP_FSYNC(fvp, MNT_WAIT, curthread);

        NFSVOPUNLOCK(fvp);
        if (error == 0 && tvp != NULL && ((nmp->nm_flag & NFSMNT_NOCTO) == 0 ||
            !NFSHASNFSV4(nmp) || !NFSHASNFSV4N(nmp) ||
            nfscl_mustflush(tvp) != 0))
                error = VOP_FSYNC(tvp, MNT_WAIT, curthread);
        if (error != 0)
                goto out;

        /*
         * If the tvp exists and is in use, sillyrename it before doing the
         * rename of the new file over it.
         * XXX Can't sillyrename a directory.
         */
        if (tvp && vrefcnt(tvp) > 1 && !VTONFS(tvp)->n_sillyrename &&
                tvp->v_type != VDIR && !nfs_sillyrename(tdvp, tvp, tcnp)) {
                vput(tvp);
                tvp = NULL;
        }

        error = nfs_renamerpc(fdvp, fvp, fcnp->cn_nameptr, fcnp->cn_namelen,
            tdvp, tvp, tcnp->cn_nameptr, tcnp->cn_namelen, false, tcnp->cn_cred,
            curthread);

        if (error == 0 && NFS_ISV4(tdvp)) {
                /*
                 * For NFSv4, check to see if it is the same name and
                 * replace the name, if it is different.
                 */
                newv4 = malloc(
                    sizeof (struct nfsv4node) +
                    tdnp->n_fhp->nfh_len + tcnp->cn_namelen - 1,
                    M_NFSV4NODE, M_WAITOK);
                NFSLOCKNODE(tdnp);
                NFSLOCKNODE(fnp);
                if (fnp->n_v4 != NULL && fvp->v_type == VREG &&
                    (fnp->n_v4->n4_namelen != tcnp->cn_namelen ||
                      NFSBCMP(tcnp->cn_nameptr, NFS4NODENAME(fnp->n_v4),
                      tcnp->cn_namelen) ||
                      tdnp->n_fhp->nfh_len != fnp->n_v4->n4_fhlen ||
                      NFSBCMP(tdnp->n_fhp->nfh_fh, fnp->n_v4->n4_data,
                        tdnp->n_fhp->nfh_len))) {
                        free(fnp->n_v4, M_NFSV4NODE);
                        fnp->n_v4 = newv4;
                        newv4 = NULL;
                        fnp->n_v4->n4_fhlen = tdnp->n_fhp->nfh_len;
                        fnp->n_v4->n4_namelen = tcnp->cn_namelen;
                        NFSBCOPY(tdnp->n_fhp->nfh_fh, fnp->n_v4->n4_data,
                            tdnp->n_fhp->nfh_len);
                        NFSBCOPY(tcnp->cn_nameptr,
                            NFS4NODENAME(fnp->n_v4), tcnp->cn_namelen);
                }
                NFSUNLOCKNODE(tdnp);
                NFSUNLOCKNODE(fnp);
                if (newv4 != NULL)
                        free(newv4, M_NFSV4NODE);
        }

        if (fvp->v_type == VDIR) {
                if (tvp != NULL && tvp->v_type == VDIR)
                        cache_purge(tdvp);
                cache_purge(fdvp);
        }

out:
        if (tdvp == tvp)
                vrele(tdvp);
        else
                vput(tdvp);
        if (tvp)
                vput(tvp);
        vrele(fdvp);
        vrele(fvp);
        /*
         * Kludge: Map ENOENT => 0 assuming that it is a reply to a retry.
         */
        if (error == ENOENT)
                error = 0;
        return (error);
}

/*
 * nfs file rename rpc called from nfs_remove() above
 */
static int
nfs_renameit(struct vnode *sdvp, struct vnode *svp, struct componentname *scnp,
    struct sillyrename *sp)
{

        return (nfs_renamerpc(sdvp, svp, scnp->cn_nameptr, scnp->cn_namelen,
            sdvp, NULL, sp->s_name, sp->s_namlen, true, scnp->cn_cred,
            curthread));
}

/*
 * Do an nfs rename rpc. Called from nfs_rename() and nfs_renameit().
 */
static int
nfs_renamerpc(struct vnode *fdvp, struct vnode *fvp, char *fnameptr,
    int fnamelen, struct vnode *tdvp, struct vnode *tvp, char *tnameptr,
    int tnamelen, bool silly, struct ucred *cred, struct thread *td)
{
        struct nfsvattr fnfsva, tnfsva, tvpnfsva;
        struct nfsnode *fdnp = VTONFS(fdvp);
        struct nfsnode *tdnp = VTONFS(tdvp);
        struct nfsmount *nmp;
        int error = 0, fattrflag, tattrflag, tvpattrflag;
        nfsremove_status tvp_status;

        nmp = VFSTONFS(fdvp->v_mount);
        error = nfsrpc_rename(fdvp, fvp, fnameptr, fnamelen, tdvp, tvp,
            tnameptr, tnamelen, &tvp_status, &fnfsva, &tnfsva, &fattrflag,
            &tattrflag, &tvpnfsva, &tvpattrflag, cred, td);
        NFSLOCKNODE(fdnp);
        fdnp->n_flag |= NMODIFIED;
        if (fattrflag != 0) {
                NFSUNLOCKNODE(fdnp);
                (void) nfscl_loadattrcache(&fdvp, &fnfsva, NULL, 0, 1);
        } else {
                fdnp->n_attrstamp = 0;
                NFSUNLOCKNODE(fdnp);
                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(fdvp);
        }
        NFSLOCKNODE(tdnp);
        tdnp->n_flag |= NMODIFIED;
        if (tattrflag != 0) {
                NFSUNLOCKNODE(tdnp);
                (void) nfscl_loadattrcache(&tdvp, &tnfsva, NULL, 0, 1);
        } else {
                tdnp->n_attrstamp = 0;
                NFSUNLOCKNODE(tdnp);
                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(tdvp);
        }

        if (tvp != NULL) {
                if (NFSHASNFSV4(nmp) && NFSHASNFSV4N(nmp) &&
                    (nmp->nm_flag & NFSMNT_NOCTO) != 0)
                        nfs_removestatus(tvp, tvp_status, silly, td);
                if (!silly && tvpattrflag != 0)
                        (void)nfscl_loadattrcache(&tvp, &tvpnfsva, NULL, 0, 1);
        }

        if (error && NFS_ISV4(fdvp))
                error = nfscl_maperr(td, error, (uid_t)0, (gid_t)0);
        return (error);
}

/*
 * nfs hard link create call
 */
static int
nfs_link(struct vop_link_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct vnode *tdvp = ap->a_tdvp;
        struct componentname *cnp = ap->a_cnp;
        struct nfsnode *np, *tdnp;
        struct nfsvattr nfsva, dnfsva;
        int error = 0, attrflag, dattrflag;

        /*
         * Push all writes to the server, so that the attribute cache
         * doesn't get "out of sync" with the server.
         * XXX There should be a better way!
         */
#ifdef notnow
        VOP_FSYNC(vp, MNT_WAIT, curthread);
#endif

        error = nfsrpc_link(tdvp, vp, cnp->cn_nameptr, cnp->cn_namelen,
            cnp->cn_cred, curthread, &dnfsva, &nfsva, &attrflag, &dattrflag);
        tdnp = VTONFS(tdvp);
        NFSLOCKNODE(tdnp);
        tdnp->n_flag |= NMODIFIED;
        if (dattrflag != 0) {
                NFSUNLOCKNODE(tdnp);
                (void) nfscl_loadattrcache(&tdvp, &dnfsva, NULL, 0, 1);
        } else {
                tdnp->n_attrstamp = 0;
                NFSUNLOCKNODE(tdnp);
                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(tdvp);
        }
        if (attrflag)
                (void) nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
        else {
                np = VTONFS(vp);
                NFSLOCKNODE(np);
                np->n_attrstamp = 0;
                NFSUNLOCKNODE(np);
                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
        }
        /*
         * If negative lookup caching is enabled, I might as well
         * add an entry for this node. Not necessary for correctness,
         * but if negative caching is enabled, then the system
         * must care about lookup caching hit rate, so...
         */
        if (VFSTONFS(vp->v_mount)->nm_negnametimeo != 0 &&
            (cnp->cn_flags & MAKEENTRY) && attrflag != 0 && error == 0) {
                if (tdvp != vp)
                        cache_enter_time(tdvp, vp, cnp, &nfsva.na_ctime, NULL);
                else
                        printf("nfs_link: bogus NFS server returned "
                            "the directory as the new link\n");
        }
        if (error && NFS_ISV4(vp))
                error = nfscl_maperr(curthread, error, (uid_t)0,
                    (gid_t)0);
        return (error);
}

/*
 * nfs symbolic link create call
 */
static int
nfs_symlink(struct vop_symlink_args *ap)
{
        struct vnode *dvp = ap->a_dvp;
        struct vattr *vap = ap->a_vap;
        struct componentname *cnp = ap->a_cnp;
        struct nfsvattr nfsva, dnfsva;
        struct nfsfh *nfhp;
        struct nfsnode *np = NULL, *dnp;
        struct vnode *newvp = NULL;
        int error = 0, attrflag, dattrflag, ret;

        vap->va_type = VLNK;
        error = nfsrpc_symlink(dvp, cnp->cn_nameptr, cnp->cn_namelen,
            ap->a_target, vap, cnp->cn_cred, curthread, &dnfsva,
            &nfsva, &nfhp, &attrflag, &dattrflag);
        if (nfhp) {
                ret = nfscl_nget(dvp->v_mount, dvp, nfhp, cnp, curthread,
                    &np, LK_EXCLUSIVE);
                if (!ret)
                        newvp = NFSTOV(np);
                else if (!error)
                        error = ret;
        }
        if (newvp != NULL) {
                if (attrflag)
                        (void) nfscl_loadattrcache(&newvp, &nfsva, NULL, 0, 1);
        } else if (!error) {
                /*
                 * If we do not have an error and we could not extract the
                 * newvp from the response due to the request being NFSv2, we
                 * have to do a lookup in order to obtain a newvp to return.
                 */
                error = nfs_lookitup(dvp, cnp->cn_nameptr, cnp->cn_namelen,
                    cnp->cn_cred, curthread, &np);
                if (!error)
                        newvp = NFSTOV(np);
        }
        if (error) {
                if (newvp)
                        vput(newvp);
                if (NFS_ISV4(dvp))
                        error = nfscl_maperr(curthread, error,
                            vap->va_uid, vap->va_gid);
        } else {
                *ap->a_vpp = newvp;
        }

        dnp = VTONFS(dvp);
        NFSLOCKNODE(dnp);
        dnp->n_flag |= NMODIFIED;
        if (dattrflag != 0) {
                NFSUNLOCKNODE(dnp);
                (void) nfscl_loadattrcache(&dvp, &dnfsva, NULL, 0, 1);
        } else {
                dnp->n_attrstamp = 0;
                NFSUNLOCKNODE(dnp);
                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(dvp);
        }
        /*
         * If negative lookup caching is enabled, I might as well
         * add an entry for this node. Not necessary for correctness,
         * but if negative caching is enabled, then the system
         * must care about lookup caching hit rate, so...
         */
        if (VFSTONFS(dvp->v_mount)->nm_negnametimeo != 0 &&
            (cnp->cn_flags & MAKEENTRY) && attrflag != 0 && error == 0) {
                if (dvp != newvp)
                        cache_enter_time(dvp, newvp, cnp, &nfsva.na_ctime,
                            NULL);
                else
                        printf("nfs_symlink: bogus NFS server returned "
                            "the directory as the new file object\n");
        }
        return (error);
}

/*
 * nfs make dir call
 */
static int
nfs_mkdir(struct vop_mkdir_args *ap)
{
        struct vnode *dvp = ap->a_dvp;
        struct vattr *vap = ap->a_vap;
        struct componentname *cnp = ap->a_cnp;
        struct nfsnode *np = NULL, *dnp;
        struct vnode *newvp = NULL;
        struct vattr vattr;
        struct nfsfh *nfhp;
        struct nfsvattr nfsva, dnfsva;
        int error = 0, attrflag, dattrflag, ret;

        if ((error = VOP_GETATTR(dvp, &vattr, cnp->cn_cred)) != 0)
                return (error);
        vap->va_type = VDIR;
        error = nfsrpc_mkdir(dvp, cnp->cn_nameptr, cnp->cn_namelen,
            vap, cnp->cn_cred, curthread, &dnfsva, &nfsva, &nfhp,
            &attrflag, &dattrflag);
        dnp = VTONFS(dvp);
        NFSLOCKNODE(dnp);
        dnp->n_flag |= NMODIFIED;
        if (dattrflag != 0) {
                NFSUNLOCKNODE(dnp);
                (void) nfscl_loadattrcache(&dvp, &dnfsva, NULL, 0, 1);
        } else {
                dnp->n_attrstamp = 0;
                NFSUNLOCKNODE(dnp);
                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(dvp);
        }
        if (nfhp) {
                ret = nfscl_nget(dvp->v_mount, dvp, nfhp, cnp, curthread,
                    &np, LK_EXCLUSIVE);
                if (!ret) {
                        newvp = NFSTOV(np);
                        if (attrflag)
                           (void) nfscl_loadattrcache(&newvp, &nfsva, NULL,
                                0, 1);
                } else if (!error)
                        error = ret;
        }
        if (!error && newvp == NULL) {
                error = nfs_lookitup(dvp, cnp->cn_nameptr, cnp->cn_namelen,
                    cnp->cn_cred, curthread, &np);
                if (!error) {
                        newvp = NFSTOV(np);
                        if (newvp->v_type != VDIR)
                                error = EEXIST;
                }
        }
        if (error) {
                if (newvp)
                        vput(newvp);
                if (NFS_ISV4(dvp))
                        error = nfscl_maperr(curthread, error,
                            vap->va_uid, vap->va_gid);
        } else {
                /*
                 * If negative lookup caching is enabled, I might as well
                 * add an entry for this node. Not necessary for correctness,
                 * but if negative caching is enabled, then the system
                 * must care about lookup caching hit rate, so...
                 */
                if (VFSTONFS(dvp->v_mount)->nm_negnametimeo != 0 &&
                    (cnp->cn_flags & MAKEENTRY) &&
                    attrflag != 0 && dattrflag != 0) {
                        if (dvp != newvp)
                                cache_enter_time(dvp, newvp, cnp,
                                    &nfsva.na_ctime, &dnfsva.na_ctime);
                        else
                                printf("nfs_mkdir: bogus NFS server returned "
                                    "the directory that the directory was "
                                    "created in as the new file object\n");
                }
                *ap->a_vpp = newvp;
        }
        return (error);
}

/*
 * nfs remove directory call
 */
static int
nfs_rmdir(struct vop_rmdir_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct vnode *dvp = ap->a_dvp;
        struct componentname *cnp = ap->a_cnp;
        struct nfsnode *dnp;
        struct nfsvattr dnfsva;
        int error, dattrflag;

        if (dvp == vp)
                return (EINVAL);
        error = nfsrpc_rmdir(dvp, cnp->cn_nameptr, cnp->cn_namelen,
            cnp->cn_cred, curthread, &dnfsva, &dattrflag);
        dnp = VTONFS(dvp);
        NFSLOCKNODE(dnp);
        dnp->n_flag |= NMODIFIED;
        if (dattrflag != 0) {
                NFSUNLOCKNODE(dnp);
                (void) nfscl_loadattrcache(&dvp, &dnfsva, NULL, 0, 1);
        } else {
                dnp->n_attrstamp = 0;
                NFSUNLOCKNODE(dnp);
                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(dvp);
        }

        cache_purge(dvp);
        cache_purge(vp);
        if (error && NFS_ISV4(dvp))
                error = nfscl_maperr(curthread, error, (uid_t)0,
                    (gid_t)0);
        /*
         * Kludge: Map ENOENT => 0 assuming that you have a reply to a retry.
         */
        if (error == ENOENT)
                error = 0;
        return (error);
}

/*
 * nfs readdir call
 */
static int
nfs_readdir(struct vop_readdir_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct nfsnode *np = VTONFS(vp);
        struct uio *uio = ap->a_uio;
        ssize_t tresid, left;
        int error = 0;
        struct vattr vattr;

        if (ap->a_eofflag != NULL)
                *ap->a_eofflag = 0;
        if (vp->v_type != VDIR) 
                return(EPERM);

        /*
         * First, check for hit on the EOF offset cache
         */
        NFSLOCKNODE(np);
        if (np->n_direofoffset > 0 && uio->uio_offset >= np->n_direofoffset &&
            (np->n_flag & NMODIFIED) == 0) {
                NFSUNLOCKNODE(np);
                if (VOP_GETATTR(vp, &vattr, ap->a_cred) == 0) {
                        NFSLOCKNODE(np);
                        if ((NFS_ISV4(vp) && np->n_change == vattr.va_filerev) ||
                            !NFS_TIMESPEC_COMPARE(&np->n_mtime, &vattr.va_mtime)) {
                                NFSUNLOCKNODE(np);
                                NFSINCRGLOBAL(nfsstatsv1.direofcache_hits);
                                if (ap->a_eofflag != NULL)
                                        *ap->a_eofflag = 1;
                                return (0);
                        } else
                                NFSUNLOCKNODE(np);
                }
        } else
                NFSUNLOCKNODE(np);

        /*
         * NFS always guarantees that directory entries don't straddle
         * DIRBLKSIZ boundaries.  As such, we need to limit the size
         * to an exact multiple of DIRBLKSIZ, to avoid copying a partial
         * directory entry.
         */
        left = uio->uio_resid % DIRBLKSIZ;
        if (left == uio->uio_resid)
                return (EINVAL);
        uio->uio_resid -= left;

        /*
         * For readdirplus, if starting to read the directory,
         * purge the name cache, since it will be reloaded by
         * this directory read.
         * This removes potentially stale name cache entries.
         */
        if (uio->uio_offset == 0 &&
            (VFSTONFS(vp->v_mount)->nm_flag & NFSMNT_RDIRPLUS) != 0)
                cache_purge(vp);

        /*
         * Call ncl_bioread() to do the real work.
         */
        tresid = uio->uio_resid;
        error = ncl_bioread(vp, uio, 0, ap->a_cred);

        if (!error && uio->uio_resid == tresid) {
                NFSINCRGLOBAL(nfsstatsv1.direofcache_misses);
                if (ap->a_eofflag != NULL)
                        *ap->a_eofflag = 1;
        }

        /* Add the partial DIRBLKSIZ (left) back in. */
        uio->uio_resid += left;
        return (error);
}

/*
 * Readdir rpc call.
 * Called from below the buffer cache by ncl_doio().
 */
int
ncl_readdirrpc(struct vnode *vp, struct uio *uiop, struct ucred *cred,
    struct thread *td)
{
        struct nfsvattr nfsva;
        nfsuint64 *cookiep, cookie;
        struct nfsnode *dnp = VTONFS(vp);
        struct nfsmount *nmp = VFSTONFS(vp->v_mount);
        int error = 0, eof, attrflag;

        KASSERT(uiop->uio_iovcnt == 1 &&
            (uiop->uio_offset & (DIRBLKSIZ - 1)) == 0 &&
            (uiop->uio_resid & (DIRBLKSIZ - 1)) == 0,
            ("nfs readdirrpc bad uio"));

        /*
         * If there is no cookie, assume directory was stale.
         */
        ncl_dircookie_lock(dnp);
        NFSUNLOCKNODE(dnp);
        cookiep = ncl_getcookie(dnp, uiop->uio_offset, 0);
        if (cookiep) {
                cookie = *cookiep;
                ncl_dircookie_unlock(dnp);
        } else {
                ncl_dircookie_unlock(dnp);              
                return (NFSERR_BAD_COOKIE);
        }

        if (NFSHASNFSV3(nmp) && !NFSHASGOTFSINFO(nmp))
                (void)ncl_fsinfo(nmp, vp, cred, td);

        error = nfsrpc_readdir(vp, uiop, &cookie, cred, td, &nfsva,
            &attrflag, &eof);
        if (attrflag)
                (void) nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);

        if (!error) {
                /*
                 * We are now either at the end of the directory or have filled
                 * the block.
                 */
                if (eof) {
                        NFSLOCKNODE(dnp);
                        dnp->n_direofoffset = uiop->uio_offset;
                        NFSUNLOCKNODE(dnp);
                } else {
                        if (uiop->uio_resid > 0)
                                printf("EEK! readdirrpc resid > 0\n");
                        ncl_dircookie_lock(dnp);
                        NFSUNLOCKNODE(dnp);
                        cookiep = ncl_getcookie(dnp, uiop->uio_offset, 1);
                        *cookiep = cookie;
                        ncl_dircookie_unlock(dnp);
                }
        } else if (NFS_ISV4(vp)) {
                error = nfscl_maperr(td, error, (uid_t)0, (gid_t)0);
        }
        return (error);
}

/*
 * NFS V3 readdir plus RPC. Used in place of ncl_readdirrpc().
 */
int
ncl_readdirplusrpc(struct vnode *vp, struct uio *uiop, struct ucred *cred,
    struct thread *td)
{
        struct nfsvattr nfsva;
        nfsuint64 *cookiep, cookie;
        struct nfsnode *dnp = VTONFS(vp);
        struct nfsmount *nmp = VFSTONFS(vp->v_mount);
        int error = 0, attrflag, eof;

        KASSERT(uiop->uio_iovcnt == 1 &&
            (uiop->uio_offset & (DIRBLKSIZ - 1)) == 0 &&
            (uiop->uio_resid & (DIRBLKSIZ - 1)) == 0,
            ("nfs readdirplusrpc bad uio"));

        /*
         * If there is no cookie, assume directory was stale.
         */
        ncl_dircookie_lock(dnp);
        NFSUNLOCKNODE(dnp);
        cookiep = ncl_getcookie(dnp, uiop->uio_offset, 0);
        if (cookiep) {
                cookie = *cookiep;
                ncl_dircookie_unlock(dnp);
        } else {
                ncl_dircookie_unlock(dnp);
                return (NFSERR_BAD_COOKIE);
        }

        if (NFSHASNFSV3(nmp) && !NFSHASGOTFSINFO(nmp))
                (void)ncl_fsinfo(nmp, vp, cred, td);
        error = nfsrpc_readdirplus(vp, uiop, &cookie, cred, td, &nfsva,
            &attrflag, &eof);
        if (attrflag)
                (void) nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);

        if (!error) {
                /*
                 * We are now either at end of the directory or have filled the
                 * the block.
                 */
                if (eof) {
                        NFSLOCKNODE(dnp);
                        dnp->n_direofoffset = uiop->uio_offset;
                        NFSUNLOCKNODE(dnp);
                } else {
                        if (uiop->uio_resid > 0)
                                printf("EEK! readdirplusrpc resid > 0\n");
                        ncl_dircookie_lock(dnp);
                        NFSUNLOCKNODE(dnp);
                        cookiep = ncl_getcookie(dnp, uiop->uio_offset, 1);
                        *cookiep = cookie;
                        ncl_dircookie_unlock(dnp);
                }
        } else if (NFS_ISV4(vp)) {
                error = nfscl_maperr(td, error, (uid_t)0, (gid_t)0);
        }
        return (error);
}

/*
 * Silly rename. To make the NFS filesystem that is stateless look a little
 * more like the "ufs" a remove of an active vnode is translated to a rename
 * to a funny looking filename that is removed by nfs_inactive on the
 * nfsnode. There is the potential for another process on a different client
 * to create the same funny name between the nfs_lookitup() fails and the
 * nfs_rename() completes, but...
 */
static int
nfs_sillyrename(struct vnode *dvp, struct vnode *vp, struct componentname *cnp)
{
        struct sillyrename *sp;
        struct nfsnode *np;
        int error;
        short pid;
        unsigned int lticks;

        cache_purge(dvp);
        np = VTONFS(vp);
        KASSERT(vp->v_type != VDIR, ("nfs: sillyrename dir"));
        sp = malloc(sizeof (struct sillyrename),
            M_NEWNFSREQ, M_WAITOK);
        sp->s_cred = crhold(cnp->cn_cred);
        sp->s_dvp = dvp;
        vref(dvp);

        /* 
         * Fudge together a funny name.
         * Changing the format of the funny name to accommodate more 
         * sillynames per directory.
         * The name is now changed to .nfs.<ticks>.<pid>.4, where ticks is 
         * CPU ticks since boot.
         */
        pid = curthread->td_proc->p_pid;
        lticks = (unsigned int)ticks;
        for ( ; ; ) {
                sp->s_namlen = sprintf(sp->s_name, 
                                       ".nfs.%08x.%04x4.4", lticks, 
                                       pid);
                if (nfs_lookitup(dvp, sp->s_name, sp->s_namlen, sp->s_cred,
                                 curthread, NULL))
                        break;
                lticks++;
        }
        error = nfs_renameit(dvp, vp, cnp, sp);
        if (error)
                goto bad;
        error = nfs_lookitup(dvp, sp->s_name, sp->s_namlen, sp->s_cred,
                curthread, &np);
        np->n_sillyrename = sp;
        return (0);
bad:
        vrele(sp->s_dvp);
        crfree(sp->s_cred);
        free(sp, M_NEWNFSREQ);
        return (error);
}

/*
 * Look up a file name and optionally either update the file handle or
 * allocate an nfsnode, depending on the value of npp.
 * npp == NULL  --> just do the lookup
 * *npp == NULL --> allocate a new nfsnode and make sure attributes are
 *                      handled too
 * *npp != NULL --> update the file handle in the vnode
 */
static int
nfs_lookitup(struct vnode *dvp, char *name, int len, struct ucred *cred,
    struct thread *td, struct nfsnode **npp)
{
        struct vnode *newvp = NULL, *vp;
        struct nfsnode *np, *dnp = VTONFS(dvp);
        struct nfsfh *nfhp, *onfhp;
        struct nfsvattr nfsva, dnfsva;
        struct componentname cn;
        int error = 0, attrflag, dattrflag;
        u_int hash;
        struct timespec ts;

        nanouptime(&ts);
        error = nfsrpc_lookup(dvp, name, len, cred, td, &dnfsva, &nfsva,
            &nfhp, &attrflag, &dattrflag, 0);
        if (dattrflag)
                (void) nfscl_loadattrcache(&dvp, &dnfsva, NULL, 0, 1);
        if (npp && !error) {
                if (*npp != NULL) {
                    np = *npp;
                    vp = NFSTOV(np);
                    /*
                     * For NFSv4, check to see if it is the same name and
                     * replace the name, if it is different.
                     */
                    if (np->n_v4 != NULL && nfsva.na_type == VREG &&
                        (np->n_v4->n4_namelen != len ||
                         NFSBCMP(name, NFS4NODENAME(np->n_v4), len) ||
                         dnp->n_fhp->nfh_len != np->n_v4->n4_fhlen ||
                         NFSBCMP(dnp->n_fhp->nfh_fh, np->n_v4->n4_data,
                         dnp->n_fhp->nfh_len))) {
                            free(np->n_v4, M_NFSV4NODE);
                            np->n_v4 = malloc(
                                sizeof (struct nfsv4node) +
                                dnp->n_fhp->nfh_len + len - 1,
                                M_NFSV4NODE, M_WAITOK);
                            np->n_v4->n4_fhlen = dnp->n_fhp->nfh_len;
                            np->n_v4->n4_namelen = len;
                            NFSBCOPY(dnp->n_fhp->nfh_fh, np->n_v4->n4_data,
                                dnp->n_fhp->nfh_len);
                            NFSBCOPY(name, NFS4NODENAME(np->n_v4), len);
                    }
                    hash = fnv_32_buf(nfhp->nfh_fh, nfhp->nfh_len,
                        FNV1_32_INIT);
                    onfhp = np->n_fhp;
                    /*
                     * Rehash node for new file handle.
                     */
                    vfs_hash_rehash(vp, hash);
                    np->n_fhp = nfhp;
                    if (onfhp != NULL)
                        free(onfhp, M_NFSFH);
                    newvp = NFSTOV(np);
                } else if (NFS_CMPFH(dnp, nfhp->nfh_fh, nfhp->nfh_len)) {
                    free(nfhp, M_NFSFH);
                    vref(dvp);
                    newvp = dvp;
                } else {
                    cn.cn_nameptr = name;
                    cn.cn_namelen = len;
                    error = nfscl_nget(dvp->v_mount, dvp, nfhp, &cn, td,
                        &np, LK_EXCLUSIVE);
                    if (error)
                        return (error);
                    newvp = NFSTOV(np);
                    /*
                     * If n_localmodtime >= time before RPC, then
                     * a file modification operation, such as
                     * VOP_SETATTR() of size, has occurred while
                     * the Lookup RPC and acquisition of the vnode
                     * happened.  As such, the attributes might
                     * be stale, with possibly an incorrect size.
                     */
                    NFSLOCKNODE(np);
                    if (timespecisset(&np->n_localmodtime) &&
                        timespeccmp(&np->n_localmodtime, &ts, >=)) {
                        NFSCL_DEBUG(4, "nfs_lookitup: localmod "
                            "stale attributes\n");
                        attrflag = 0;
                    }
                    NFSUNLOCKNODE(np);
                }
                if (!attrflag && *npp == NULL) {
                        if (newvp == dvp)
                                vrele(newvp);
                        else
                                vput(newvp);
                        return (ENOENT);
                }
                if (attrflag)
                        (void) nfscl_loadattrcache(&newvp, &nfsva, NULL, 0, 1);
        }
        if (npp && *npp == NULL) {
                if (error) {
                        if (newvp) {
                                if (newvp == dvp)
                                        vrele(newvp);
                                else
                                        vput(newvp);
                        }
                } else
                        *npp = np;
        }
        if (error && NFS_ISV4(dvp))
                error = nfscl_maperr(td, error, (uid_t)0, (gid_t)0);
        return (error);
}

/*
 * Nfs Version 3 and 4 commit rpc
 */
int
ncl_commit(struct vnode *vp, u_quad_t offset, int cnt, struct ucred *cred,
   struct thread *td)
{
        struct nfsvattr nfsva;
        struct nfsmount *nmp = VFSTONFS(vp->v_mount);
        struct nfsnode *np;
        struct uio uio;
        int error, attrflag;

        np = VTONFS(vp);
        error = EIO;
        attrflag = 0;
        if (NFSHASPNFS(nmp) && (np->n_flag & NDSCOMMIT) != 0) {
                uio.uio_offset = offset;
                uio.uio_resid = cnt;
                error = nfscl_doiods(vp, &uio, NULL, NULL,
                    NFSV4OPEN_ACCESSWRITE, 1, cred, td);
                if (error != 0) {
                        NFSLOCKNODE(np);
                        np->n_flag &= ~NDSCOMMIT;
                        NFSUNLOCKNODE(np);
                }
        }
        if (error != 0) {
                mtx_lock(&nmp->nm_mtx);
                if ((nmp->nm_state & NFSSTA_HASWRITEVERF) == 0) {
                        mtx_unlock(&nmp->nm_mtx);
                        return (0);
                }
                mtx_unlock(&nmp->nm_mtx);
                error = nfsrpc_commit(vp, offset, cnt, cred, td, &nfsva,
                    &attrflag);
        }
        if (attrflag != 0)
                (void) nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
        if (error != 0 && NFS_ISV4(vp))
                error = nfscl_maperr(td, error, (uid_t)0, (gid_t)0);
        return (error);
}

/*
 * Strategy routine.
 * For async requests when nfsiod(s) are running, queue the request by
 * calling ncl_asyncio(), otherwise just all ncl_doio() to do the
 * request.
 */
static int
nfs_strategy(struct vop_strategy_args *ap)
{
        struct buf *bp;
        struct vnode *vp;
        struct ucred *cr;

        bp = ap->a_bp;
        vp = ap->a_vp;
        KASSERT(bp->b_vp == vp, ("missing b_getvp"));
        KASSERT(!(bp->b_flags & B_DONE),
            ("nfs_strategy: buffer %p unexpectedly marked B_DONE", bp));

        if (vp->v_type == VREG && bp->b_blkno == bp->b_lblkno)
                bp->b_blkno = bp->b_lblkno * (vp->v_bufobj.bo_bsize /
                    DEV_BSIZE);
        if (bp->b_iocmd == BIO_READ)
                cr = bp->b_rcred;
        else
                cr = bp->b_wcred;

        /*
         * If the op is asynchronous and an i/o daemon is waiting
         * queue the request, wake it up and wait for completion
         * otherwise just do it ourselves.
         */
        if ((bp->b_flags & B_ASYNC) == 0 ||
            ncl_asyncio(VFSTONFS(vp->v_mount), bp, NOCRED, curthread))
                (void) ncl_doio(vp, bp, cr, curthread, 1);
        return (0);
}

/*
 * fsync vnode op. Just call ncl_flush() with commit == 1.
 */
/* ARGSUSED */
static int
nfs_fsync(struct vop_fsync_args *ap)
{

        if (ap->a_vp->v_type != VREG) {
                /*
                 * For NFS, metadata is changed synchronously on the server,
                 * so there is nothing to flush. Also, ncl_flush() clears
                 * the NMODIFIED flag and that shouldn't be done here for
                 * directories.
                 */
                return (0);
        }
        return (ncl_flush(ap->a_vp, ap->a_waitfor, ap->a_td, 1, 0));
}

/*
 * Flush all the blocks associated with a vnode.
 *      Walk through the buffer pool and push any dirty pages
 *      associated with the vnode.
 * If the called_from_renewthread argument is TRUE, it has been called
 * from the NFSv4 renew thread and, as such, cannot block indefinitely
 * waiting for a buffer write to complete.
 */
int
ncl_flush(struct vnode *vp, int waitfor, struct thread *td,
    int commit, int called_from_renewthread)
{
        struct nfsnode *np = VTONFS(vp);
        struct buf *bp;
        int i;
        struct buf *nbp;
        struct nfsmount *nmp = VFSTONFS(vp->v_mount);
        int error = 0, slptimeo = 0, slpflag = 0, retv, bvecpos;
        int passone = 1, trycnt = 0;
        u_quad_t off, endoff, toff;
        struct ucred* wcred = NULL;
        struct buf **bvec = NULL;
        struct bufobj *bo;
#ifndef NFS_COMMITBVECSIZ
#define NFS_COMMITBVECSIZ       20
#endif
        struct buf *bvec_on_stack[NFS_COMMITBVECSIZ];
        u_int bvecsize = 0, bveccount;
        struct timespec ts;

        if (called_from_renewthread != 0)
                slptimeo = hz;
        if (nmp->nm_flag & NFSMNT_INT)
                slpflag = PCATCH;
        if (!commit)
                passone = 0;
        bo = &vp->v_bufobj;
        /*
         * A b_flags == (B_DELWRI | B_NEEDCOMMIT) block has been written to the
         * server, but has not been committed to stable storage on the server
         * yet. On the first pass, the byte range is worked out and the commit
         * rpc is done. On the second pass, bwrite() is called to do the
         * job.
         */
again:
        off = (u_quad_t)-1;
        endoff = 0;
        bvecpos = 0;
        if (NFS_ISV34(vp) && commit) {
                if (bvec != NULL && bvec != bvec_on_stack)
                        free(bvec, M_TEMP);
                /*
                 * Count up how many buffers waiting for a commit.
                 */
                bveccount = 0;
                BO_LOCK(bo);
                TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
                        if (!BUF_ISLOCKED(bp) &&
                            (bp->b_flags & (B_DELWRI | B_NEEDCOMMIT))
                                == (B_DELWRI | B_NEEDCOMMIT))
                                bveccount++;
                }
                /*
                 * Allocate space to remember the list of bufs to commit.  It is
                 * important to use M_NOWAIT here to avoid a race with nfs_write.
                 * If we can't get memory (for whatever reason), we will end up
                 * committing the buffers one-by-one in the loop below.
                 */
                if (bveccount > NFS_COMMITBVECSIZ) {
                        /*
                         * Release the vnode interlock to avoid a lock
                         * order reversal.
                         */
                        BO_UNLOCK(bo);
                        bvec = (struct buf **)
                                malloc(bveccount * sizeof(struct buf *),
                                       M_TEMP, M_NOWAIT);
                        BO_LOCK(bo);
                        if (bvec == NULL) {
                                bvec = bvec_on_stack;
                                bvecsize = NFS_COMMITBVECSIZ;
                        } else
                                bvecsize = bveccount;
                } else {
                        bvec = bvec_on_stack;
                        bvecsize = NFS_COMMITBVECSIZ;
                }
                TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
                        if (bvecpos >= bvecsize)
                                break;
                        if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) {
                                nbp = TAILQ_NEXT(bp, b_bobufs);
                                continue;
                        }
                        if ((bp->b_flags & (B_DELWRI | B_NEEDCOMMIT)) !=
                            (B_DELWRI | B_NEEDCOMMIT)) {
                                BUF_UNLOCK(bp);
                                nbp = TAILQ_NEXT(bp, b_bobufs);
                                continue;
                        }
                        BO_UNLOCK(bo);
                        bremfree(bp);
                        /*
                         * Work out if all buffers are using the same cred
                         * so we can deal with them all with one commit.
                         *
                         * NOTE: we are not clearing B_DONE here, so we have
                         * to do it later on in this routine if we intend to
                         * initiate I/O on the bp.
                         *
                         * Note: to avoid loopback deadlocks, we do not
                         * assign b_runningbufspace.
                         */
                        if (wcred == NULL)
                                wcred = bp->b_wcred;
                        else if (wcred != bp->b_wcred)
                                wcred = NOCRED;
                        vfs_busy_pages(bp, 0);

                        BO_LOCK(bo);
                        /*
                         * bp is protected by being locked, but nbp is not
                         * and vfs_busy_pages() may sleep.  We have to
                         * recalculate nbp.
                         */
                        nbp = TAILQ_NEXT(bp, b_bobufs);

                        /*
                         * A list of these buffers is kept so that the
                         * second loop knows which buffers have actually
                         * been committed. This is necessary, since there
                         * may be a race between the commit rpc and new
                         * uncommitted writes on the file.
                         */
                        bvec[bvecpos++] = bp;
                        toff = ((u_quad_t)bp->b_blkno) * DEV_BSIZE +
                                bp->b_dirtyoff;
                        if (toff < off)
                                off = toff;
                        toff += (u_quad_t)(bp->b_dirtyend - bp->b_dirtyoff);
                        if (toff > endoff)
                                endoff = toff;
                }
                BO_UNLOCK(bo);
        }
        if (bvecpos > 0) {
                /*
                 * Commit data on the server, as required.
                 * If all bufs are using the same wcred, then use that with
                 * one call for all of them, otherwise commit each one
                 * separately.
                 */
                if (wcred != NOCRED)
                        retv = ncl_commit(vp, off, (int)(endoff - off),
                                          wcred, td);
                else {
                        retv = 0;
                        for (i = 0; i < bvecpos; i++) {
                                off_t off, size;
                                bp = bvec[i];
                                off = ((u_quad_t)bp->b_blkno) * DEV_BSIZE +
                                        bp->b_dirtyoff;
                                size = (u_quad_t)(bp->b_dirtyend
                                                  - bp->b_dirtyoff);
                                retv = ncl_commit(vp, off, (int)size,
                                                  bp->b_wcred, td);
                                if (retv) break;
                        }
                }

                if (retv == NFSERR_STALEWRITEVERF)
                        ncl_clearcommit(vp->v_mount);

                /*
                 * Now, either mark the blocks I/O done or mark the
                 * blocks dirty, depending on whether the commit
                 * succeeded.
                 */
                for (i = 0; i < bvecpos; i++) {
                        bp = bvec[i];
                        bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
                        if (!NFSCL_FORCEDISM(vp->v_mount) && retv) {
                                /*
                                 * Error, leave B_DELWRI intact
                                 */
                                vfs_unbusy_pages(bp);
                                brelse(bp);
                        } else {
                                /*
                                 * Success, remove B_DELWRI ( bundirty() ).
                                 *
                                 * b_dirtyoff/b_dirtyend seem to be NFS
                                 * specific.  We should probably move that
                                 * into bundirty(). XXX
                                 */
                                bufobj_wref(bo);
                                bp->b_flags |= B_ASYNC;
                                bundirty(bp);
                                bp->b_flags &= ~B_DONE;
                                bp->b_ioflags &= ~BIO_ERROR;
                                bp->b_dirtyoff = bp->b_dirtyend = 0;
                                bufdone(bp);
                        }
                }
        }

        /*
         * Start/do any write(s) that are required.
         */
loop:
        BO_LOCK(bo);
        TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
                if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) {
                        if (waitfor != MNT_WAIT || passone)
                                continue;

                        error = BUF_TIMELOCK(bp,
                            LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
                            BO_LOCKPTR(bo), "nfsfsync", slpflag, slptimeo);
                        if (error == 0) {
                                BUF_UNLOCK(bp);
                                goto loop;
                        }
                        if (error == ENOLCK) {
                                error = 0;
                                goto loop;
                        }
                        if (called_from_renewthread != 0) {
                                /*
                                 * Return EIO so the flush will be retried
                                 * later.
                                 */
                                error = EIO;
                                goto done;
                        }
                        if (newnfs_sigintr(nmp, td)) {
                                error = EINTR;
                                goto done;
                        }
                        if (slpflag == PCATCH) {
                                slpflag = 0;
                                slptimeo = 2 * hz;
                        }
                        goto loop;
                }
                if ((bp->b_flags & B_DELWRI) == 0)
                        panic("nfs_fsync: not dirty");
                if ((passone || !commit) && (bp->b_flags & B_NEEDCOMMIT)) {
                        BUF_UNLOCK(bp);
                        continue;
                }
                BO_UNLOCK(bo);
                bremfree(bp);
                bp->b_flags |= B_ASYNC;
                bwrite(bp);
                if (newnfs_sigintr(nmp, td)) {
                        error = EINTR;
                        goto done;
                }
                goto loop;
        }
        if (passone) {
                passone = 0;
                BO_UNLOCK(bo);
                goto again;
        }
        if (waitfor == MNT_WAIT) {
                while (bo->bo_numoutput) {
                        error = bufobj_wwait(bo, slpflag, slptimeo);
                        if (error) {
                            BO_UNLOCK(bo);
                            if (called_from_renewthread != 0) {
                                /*
                                 * Return EIO so that the flush will be
                                 * retried later.
                                 */
                                error = EIO;
                                goto done;
                            }
                            error = newnfs_sigintr(nmp, td);
                            if (error)
                                goto done;
                            if (slpflag == PCATCH) {
                                slpflag = 0;
                                slptimeo = 2 * hz;
                            }
                            BO_LOCK(bo);
                        }
                }
                if (bo->bo_dirty.bv_cnt != 0 && commit) {
                        BO_UNLOCK(bo);
                        goto loop;
                }
                /*
                 * Wait for all the async IO requests to drain
                 */
                BO_UNLOCK(bo);
        } else
                BO_UNLOCK(bo);
        if (NFSHASPNFS(nmp)) {
                nfscl_layoutcommit(vp, td);
                /*
                 * Invalidate the attribute cache, since writes to a DS
                 * won't update the size attribute.
                 */
                NFSLOCKNODE(np);
                np->n_attrstamp = 0;
        } else
                NFSLOCKNODE(np);
        if (np->n_flag & NWRITEERR) {
                error = np->n_error;
                np->n_flag &= ~NWRITEERR;
        }
        if (commit && bo->bo_dirty.bv_cnt == 0 &&
            bo->bo_numoutput == 0)
                np->n_flag &= ~NMODIFIED;
        NFSUNLOCKNODE(np);
done:
        if (bvec != NULL && bvec != bvec_on_stack)
                free(bvec, M_TEMP);
        if (error == 0 && commit != 0 && waitfor == MNT_WAIT &&
            (bo->bo_dirty.bv_cnt != 0 || bo->bo_numoutput != 0)) {
                if (trycnt++ < 5) {
                        /* try, try again... */
                        passone = 1;
                        wcred = NULL;
                        bvec = NULL;
                        bvecsize = 0;
                        goto again;
                }
                vn_printf(vp, "ncl_flush failed");
                error = called_from_renewthread != 0 ? EIO : EBUSY;
        }
        if (error == 0) {
                nanouptime(&ts);
                NFSLOCKNODE(np);
                np->n_localmodtime = ts;
                NFSUNLOCKNODE(np);
        }
        return (error);
}

/*
 * NFS advisory byte-level locks.
 */
static int
nfs_advlock(struct vop_advlock_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct ucred *cred;
        struct nfsnode *np = VTONFS(ap->a_vp);
        struct proc *p = (struct proc *)ap->a_id;
        struct thread *td = curthread;  /* XXX */
        struct vattr va;
        int ret, error;
        u_quad_t size;
        struct nfsmount *nmp;

        error = NFSVOPLOCK(vp, LK_EXCLUSIVE);
        if (error != 0)
                return (EBADF);
        nmp = VFSTONFS(vp->v_mount);
        if (!NFS_ISV4(vp) || (nmp->nm_flag & NFSMNT_NOLOCKD) != 0) {
                if ((nmp->nm_flag & NFSMNT_NOLOCKD) != 0) {
                        size = np->n_size;
                        NFSVOPUNLOCK(vp);
                        error = lf_advlock(ap, &(vp->v_lockf), size);
                } else {
                        if (nfs_advlock_p != NULL)
                                error = nfs_advlock_p(ap);
                        else {
                                NFSVOPUNLOCK(vp);
                                error = ENOLCK;
                        }
                }
                if (error == 0 && ap->a_op == F_SETLK) {
                        error = NFSVOPLOCK(vp, LK_SHARED);
                        if (error == 0) {
                                /* Mark that a file lock has been acquired. */
                                NFSLOCKNODE(np);
                                np->n_flag |= NHASBEENLOCKED;
                                NFSUNLOCKNODE(np);
                                NFSVOPUNLOCK(vp);
                        }
                }
                return (error);
        } else if ((ap->a_flags & (F_POSIX | F_FLOCK)) != 0) {
                if (vp->v_type != VREG) {
                        error = EINVAL;
                        goto out;
                }
                if ((ap->a_flags & F_POSIX) != 0)
                        cred = p->p_ucred;
                else
                        cred = td->td_ucred;

                /*
                 * If this is unlocking a write locked region, flush and
                 * commit them before unlocking. This is required by
                 * RFC3530 Sec. 9.3.2.
                 */
                if (ap->a_op == F_UNLCK &&
                    nfscl_checkwritelocked(vp, ap->a_fl, cred, td, ap->a_id,
                    ap->a_flags))
                        (void) ncl_flush(vp, MNT_WAIT, td, 1, 0);

                /*
                 * Mark NFS node as might have acquired a lock.
                 * This is separate from NHASBEENLOCKED, because it must
                 * be done before the nfsrpc_advlock() call, which might
                 * add a nfscllock structure to the client state.
                 * It is used to check for the case where a nfscllock
                 * state structure cannot exist for the file.
                 * Only done for "oneopenown" NFSv4.1/4.2 mounts.
                 */
                if (NFSHASNFSV4N(nmp) && NFSHASONEOPENOWN(nmp)) {
                        NFSLOCKNODE(np);
                        np->n_flag |= NMIGHTBELOCKED;
                        NFSUNLOCKNODE(np);
                }

                /*
                 * Loop around doing the lock op, while a blocking lock
                 * must wait for the lock op to succeed.
                 */
                do {
                        ret = nfsrpc_advlock(vp, np->n_size, ap->a_op,
                            ap->a_fl, 0, cred, td, ap->a_id, ap->a_flags);
                        if (ret == NFSERR_DENIED && (ap->a_flags & F_WAIT) &&
                            ap->a_op == F_SETLK) {
                                NFSVOPUNLOCK(vp);
                                error = nfs_catnap(PZERO | PCATCH, ret,
                                    "ncladvl");
                                if (error)
                                        return (EINTR);
                                NFSVOPLOCK(vp, LK_EXCLUSIVE | LK_RETRY);
                                if (VN_IS_DOOMED(vp)) {
                                        error = EBADF;
                                        goto out;
                                }
                        }
                } while (ret == NFSERR_DENIED && (ap->a_flags & F_WAIT) &&
                     ap->a_op == F_SETLK);
                if (ret == NFSERR_DENIED) {
                        error = EAGAIN;
                        goto out;
                } else if (ret == EINVAL || ret == EBADF || ret == EINTR) {
                        error = ret;
                        goto out;
                } else if (ret != 0) {
                        error = EACCES;
                        goto out;
                }

                /*
                 * Now, if we just got a lock, invalidate data in the buffer
                 * cache, as required, so that the coherency conforms with
                 * RFC3530 Sec. 9.3.2.
                 */
                if (ap->a_op == F_SETLK) {
                        if ((np->n_flag & NMODIFIED) == 0) {
                                np->n_attrstamp = 0;
                                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
                                ret = VOP_GETATTR(vp, &va, cred);
                        }
                        if ((np->n_flag & NMODIFIED) || ret ||
                            np->n_change != va.va_filerev) {
                                (void) ncl_vinvalbuf(vp, V_SAVE, td, 1);
                                np->n_attrstamp = 0;
                                KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
                                ret = VOP_GETATTR(vp, &va, cred);
                                if (!ret) {
                                        np->n_mtime = va.va_mtime;
                                        np->n_change = va.va_filerev;
                                }
                        }
                        /* Mark that a file lock has been acquired. */
                        NFSLOCKNODE(np);
                        np->n_flag |= NHASBEENLOCKED;
                        NFSUNLOCKNODE(np);
                }
        } else
                error = EOPNOTSUPP;
out:
        NFSVOPUNLOCK(vp);
        return (error);
}

/*
 * NFS advisory byte-level locks.
 */
static int
nfs_advlockasync(struct vop_advlockasync_args *ap)
{
        struct vnode *vp = ap->a_vp;
        u_quad_t size;
        int error;

        error = NFSVOPLOCK(vp, LK_SHARED);
        if (error)
                return (error);
        if (NFS_ISV4(vp)) {
                NFSVOPUNLOCK(vp);
                return (EOPNOTSUPP);
        }
        if ((VFSTONFS(vp->v_mount)->nm_flag & NFSMNT_NOLOCKD) != 0) {
                size = VTONFS(vp)->n_size;
                NFSVOPUNLOCK(vp);
                error = lf_advlockasync(ap, &(vp->v_lockf), size);
        } else {
                NFSVOPUNLOCK(vp);
                error = EOPNOTSUPP;
        }
        return (error);
}

/*
 * Print out the contents of an nfsnode.
 */
static int
nfs_print(struct vop_print_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct nfsnode *np = VTONFS(vp);

        printf("\tfileid %jd fsid 0x%jx", (uintmax_t)np->n_vattr.na_fileid,
            (uintmax_t)np->n_vattr.na_fsid);
        if (vp->v_type == VFIFO)
                fifo_printinfo(vp);
        printf("\n");
        return (0);
}

/*
 * nfs special file access vnode op.
 * Essentially just get vattr and then imitate iaccess() since the device is
 * local to the client.
 */
static int
nfsspec_access(struct vop_access_args *ap)
{
        struct vattr *vap;
        struct ucred *cred = ap->a_cred;
        struct vnode *vp = ap->a_vp;
        accmode_t accmode = ap->a_accmode;
        struct vattr vattr;
        int error;

        /*
         * Disallow write attempts on filesystems mounted read-only;
         * unless the file is a socket, fifo, or a block or character
         * device resident on the filesystem.
         */
        if ((accmode & VWRITE) && (vp->v_mount->mnt_flag & MNT_RDONLY)) {
                switch (vp->v_type) {
                case VREG:
                case VDIR:
                case VLNK:
                        return (EROFS);
                default:
                        break;
                }
        }
        vap = &vattr;
        error = VOP_GETATTR(vp, vap, cred);
        if (error)
                goto out;
        error = vaccess(vp->v_type, vap->va_mode, vap->va_uid, vap->va_gid,
            accmode, cred);
out:
        return error;
}

/*
 * Read wrapper for fifos.
 */
static int
nfsfifo_read(struct vop_read_args *ap)
{
        struct nfsnode *np = VTONFS(ap->a_vp);
        int error;

        /*
         * Set access flag.
         */
        NFSLOCKNODE(np);
        np->n_flag |= NACC;
        vfs_timestamp(&np->n_atim);
        NFSUNLOCKNODE(np);
        error = fifo_specops.vop_read(ap);
        return error;   
}

/*
 * Write wrapper for fifos.
 */
static int
nfsfifo_write(struct vop_write_args *ap)
{
        struct nfsnode *np = VTONFS(ap->a_vp);

        /*
         * Set update flag.
         */
        NFSLOCKNODE(np);
        np->n_flag |= NUPD;
        vfs_timestamp(&np->n_mtim);
        NFSUNLOCKNODE(np);
        return(fifo_specops.vop_write(ap));
}

/*
 * Close wrapper for fifos.
 *
 * Update the times on the nfsnode then do fifo close.
 */
static int
nfsfifo_close(struct vop_close_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct nfsnode *np = VTONFS(vp);
        struct vattr vattr;
        struct timespec ts;

        NFSLOCKNODE(np);
        if (np->n_flag & (NACC | NUPD)) {
                vfs_timestamp(&ts);
                if (np->n_flag & NACC)
                        np->n_atim = ts;
                if (np->n_flag & NUPD)
                        np->n_mtim = ts;
                np->n_flag |= NCHG;
                if (vrefcnt(vp) == 1 &&
                    (vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
                        VATTR_NULL(&vattr);
                        if (np->n_flag & NACC)
                                vattr.va_atime = np->n_atim;
                        if (np->n_flag & NUPD)
                                vattr.va_mtime = np->n_mtim;
                        NFSUNLOCKNODE(np);
                        (void)VOP_SETATTR(vp, &vattr, ap->a_cred);
                        goto out;
                }
        }
        NFSUNLOCKNODE(np);
out:
        return (fifo_specops.vop_close(ap));
}

static int
nfs_getacl(struct vop_getacl_args *ap)
{
        int error;

        if (ap->a_type != ACL_TYPE_NFS4 && ap->a_type != ACL_TYPE_ACCESS &&
            ap->a_type != ACL_TYPE_DEFAULT)
                return (EOPNOTSUPP);
        if (ap->a_type == ACL_TYPE_DEFAULT && ap->a_vp->v_type != VDIR)
                return (EINVAL);
        error = nfsrpc_getacl(ap->a_vp, ap->a_type, ap->a_cred, ap->a_td,
            ap->a_aclp);
        if (error == 0 && ap->a_aclp->acl_cnt == 0 &&
            ap->a_type != ACL_TYPE_DEFAULT)
                return (EOPNOTSUPP);
        if (error > NFSERR_STALE) {
                (void) nfscl_maperr(ap->a_td, error, (uid_t)0, (gid_t)0);
                error = EPERM;
        }
        return (error);
}

static int
nfs_setacl(struct vop_setacl_args *ap)
{
        int error;

        if (ap->a_type != ACL_TYPE_NFS4 && ap->a_type != ACL_TYPE_ACCESS &&
            ap->a_type != ACL_TYPE_DEFAULT)
                return (EOPNOTSUPP);
        if (ap->a_aclp == NULL) {
                if (ap->a_type != ACL_TYPE_DEFAULT)
                        return (EINVAL);
                if (ap->a_vp->v_type != VDIR)
                        return (ENOTDIR);
        }
        error = nfsrpc_setacl(ap->a_vp, ap->a_type, ap->a_cred, ap->a_td,
            ap->a_aclp);
        if (error > NFSERR_STALE) {
                (void) nfscl_maperr(ap->a_td, error, (uid_t)0, (gid_t)0);
                error = EPERM;
        }
        return (error);
}

/*
 * VOP_ADVISE for NFS.
 * Just return 0 for any errors, since it is just a hint.
 */
static int
nfs_advise(struct vop_advise_args *ap)
{
        struct thread *td = curthread;
        struct nfsmount *nmp;
        uint64_t len;
        int error;

        /*
         * First do vop_stdadvise() to handle the buffer cache.
         */
        error = vop_stdadvise(ap);
        if (error != 0)
                return (error);
        if (ap->a_start < 0 || ap->a_end < 0)
                return (0);
        if (ap->a_end == OFF_MAX)
                len = 0;
        else if (ap->a_end < ap->a_start)
                return (0);
        else
                len = ap->a_end - ap->a_start + 1;
        nmp = VFSTONFS(ap->a_vp->v_mount);
        mtx_lock(&nmp->nm_mtx);
        if (!NFSHASNFSV4(nmp) || nmp->nm_minorvers < NFSV42_MINORVERSION ||
            (NFSHASPNFS(nmp) && (nmp->nm_privflag & NFSMNTP_IOADVISETHRUMDS) ==
            0) || (nmp->nm_privflag & NFSMNTP_NOADVISE) != 0) {
                mtx_unlock(&nmp->nm_mtx);
                return (0);
        }
        mtx_unlock(&nmp->nm_mtx);
        error = nfsrpc_advise(ap->a_vp, ap->a_start, len, ap->a_advice,
            td->td_ucred, td);
        if (error == NFSERR_NOTSUPP) {
                mtx_lock(&nmp->nm_mtx);
                nmp->nm_privflag |= NFSMNTP_NOADVISE;
                mtx_unlock(&nmp->nm_mtx);
        }
        return (0);
}

/*
 * nfs allocate call
 */
static int
nfs_allocate(struct vop_allocate_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct thread *td = curthread;
        struct nfsvattr nfsva;
        struct nfsmount *nmp;
        struct nfsnode *np;
        off_t alen;
        int attrflag, error, ret;
        struct timespec ts;
        struct uio io;

        attrflag = 0;
        nmp = VFSTONFS(vp->v_mount);
        np = VTONFS(vp);
        mtx_lock(&nmp->nm_mtx);
        if (NFSHASNFSV4(nmp) && nmp->nm_minorvers >= NFSV42_MINORVERSION &&
            (nmp->nm_privflag & NFSMNTP_NOALLOCATE) == 0) {
                mtx_unlock(&nmp->nm_mtx);
                alen = *ap->a_len;
                if ((uint64_t)alen > nfs_maxalloclen)
                        alen = nfs_maxalloclen;

                /* Check the file size limit. */
                io.uio_offset = *ap->a_offset;
                io.uio_resid = alen;
                error = vn_rlimit_fsize(vp, &io, td);

                /*
                 * Flush first to ensure that the allocate adds to the
                 * file's allocation on the server.
                 */
                if (error == 0) {
                        vnode_pager_clean_sync(vp);
                        error = ncl_flush(vp, MNT_WAIT, td, 1, 0);
                }
                if (error == 0)
                        error = nfsrpc_allocate(vp, *ap->a_offset, alen,
                            &nfsva, &attrflag, ap->a_cred, td);
                if (error == 0) {
                        *ap->a_offset += alen;
                        *ap->a_len -= alen;
                        nanouptime(&ts);
                        NFSLOCKNODE(np);
                        np->n_localmodtime = ts;
                        NFSUNLOCKNODE(np);
                } else if (error == NFSERR_NOTSUPP) {
                        mtx_lock(&nmp->nm_mtx);
                        nmp->nm_privflag |= NFSMNTP_NOALLOCATE;
                        mtx_unlock(&nmp->nm_mtx);
                        error = EOPNOTSUPP;
                }
        } else {
                /*
                 * Pre-v4.2 NFS server that doesn't support it, or a newer
                 * NFS server that has indicated that it doesn't support it.
                 */
                mtx_unlock(&nmp->nm_mtx);
                error = EOPNOTSUPP;
        }
        if (attrflag != 0) {
                ret = nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
                if (error == 0 && ret != 0)
                        error = ret;
        }
        if (error != 0)
                error = nfscl_maperr(td, error, (uid_t)0, (gid_t)0);
        return (error);
}

/*
 * nfs deallocate call
 */
static int
nfs_deallocate(struct vop_deallocate_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct thread *td = curthread;
        struct nfsvattr nfsva;
        struct nfsmount *nmp;
        struct nfsnode *np;
        off_t tlen, mlen;
        int attrflag, error, ret;
        bool clipped;
        struct timespec ts;

        error = 0;
        attrflag = 0;
        nmp = VFSTONFS(vp->v_mount);
        np = VTONFS(vp);
        mtx_lock(&nmp->nm_mtx);
        if (NFSHASNFSV4(nmp) && nmp->nm_minorvers >= NFSV42_MINORVERSION &&
            (nmp->nm_privflag & NFSMNTP_NODEALLOCATE) == 0) {
                mtx_unlock(&nmp->nm_mtx);
                tlen = omin(OFF_MAX - *ap->a_offset, *ap->a_len);
                NFSCL_DEBUG(4, "dealloc: off=%jd len=%jd maxfilesize=%ju\n",
                    (intmax_t)*ap->a_offset, (intmax_t)tlen,
                    (uintmax_t)nmp->nm_maxfilesize);
                if ((uint64_t)*ap->a_offset >= nmp->nm_maxfilesize) {
                        /* Avoid EFBIG error return from the NFSv4.2 server. */
                        *ap->a_len = 0;
                        return (0);
                }
                clipped = false;
                if ((uint64_t)*ap->a_offset + tlen > nmp->nm_maxfilesize)
                        tlen = nmp->nm_maxfilesize - *ap->a_offset;
                if ((uint64_t)*ap->a_offset < np->n_size) {
                        /* Limit the len to nfs_maxalloclen before EOF. */
                        mlen = omin((off_t)np->n_size - *ap->a_offset, tlen);
                        if ((uint64_t)mlen > nfs_maxalloclen) {
                                NFSCL_DEBUG(4, "dealloc: tlen maxalloclen\n");
                                tlen = nfs_maxalloclen;
                                clipped = true;
                        }
                }
                if (error == 0)
                        error = ncl_vinvalbuf(vp, V_SAVE, td, 1);
                if (error == 0) {
                        vnode_pager_purge_range(vp, *ap->a_offset,
                            *ap->a_offset + tlen);
                        error = nfsrpc_deallocate(vp, *ap->a_offset, tlen,
                            &nfsva, &attrflag, ap->a_cred, td);
                        NFSCL_DEBUG(4, "dealloc: rpc=%d\n", error);
                }
                if (error == 0) {
                        NFSCL_DEBUG(4, "dealloc: attrflag=%d na_size=%ju\n",
                            attrflag, (uintmax_t)nfsva.na_size);
                        nanouptime(&ts);
                        NFSLOCKNODE(np);
                        np->n_localmodtime = ts;
                        NFSUNLOCKNODE(np);
                        if (attrflag != 0) {
                                if ((uint64_t)*ap->a_offset < nfsva.na_size)
                                        *ap->a_offset += omin((off_t)
                                            nfsva.na_size - *ap->a_offset,
                                            tlen);
                        }
                        if (clipped && tlen < *ap->a_len)
                                *ap->a_len -= tlen;
                        else
                                *ap->a_len = 0;
                } else if (error == NFSERR_NOTSUPP) {
                        mtx_lock(&nmp->nm_mtx);
                        nmp->nm_privflag |= NFSMNTP_NODEALLOCATE;
                        mtx_unlock(&nmp->nm_mtx);
                }
        } else {
                mtx_unlock(&nmp->nm_mtx);
                error = EIO;
        }
        /*
         * If the NFS server cannot perform the Deallocate operation, just call
         * vop_stddeallocate() to perform it.
         */
        if (error != 0 && error != NFSERR_FBIG && error != NFSERR_INVAL) {
                error = vop_stddeallocate(ap);
                NFSCL_DEBUG(4, "dealloc: stddeallocate=%d\n", error);
        }
        if (attrflag != 0) {
                ret = nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
                if (error == 0 && ret != 0)
                        error = ret;
        }
        if (error != 0)
                error = nfscl_maperr(td, error, (uid_t)0, (gid_t)0);
        return (error);
}

/*
 * nfs copy_file_range call
 */
static int
nfs_copy_file_range(struct vop_copy_file_range_args *ap)
{
        struct vnode *invp = ap->a_invp;
        struct vnode *outvp = ap->a_outvp;
        struct mount *mp;
        vm_object_t invp_obj;
        struct nfsvattr innfsva, outnfsva;
        struct vattr va, *vap;
        struct uio io;
        struct nfsmount *nmp;
        struct nfsnode *np;
        size_t len, len2;
        ssize_t r;
        int error, inattrflag, outattrflag, ret, ret2, invp_lock;
        off_t inoff, outoff;
        bool consecutive, must_commit, onevp, toeof, tryclone, tryoutcred;
        bool mustclone;

        /*
         * NFSv4.2 Copy is not permitted for infile == outfile.
         * The NFSv4.2 Clone operation does work on non-overlapping
         * byte ranges in the same file, but only if offsets
         * (and len if not to EOF) are aligned properly.
         * TODO: copy_file_range() between multiple NFS mountpoints
         * --> This is not possible now, since each mount appears to
         *     the NFSv4.n server as a separate client.
         */
        if ((invp == outvp && (ap->a_flags & COPY_FILE_RANGE_CLONE) == 0) ||
            (invp != outvp && invp->v_mount != outvp->v_mount)) {
generic_copy:
                return (ENOSYS);
        }
        if (invp == outvp) {
                onevp = true;
                invp_lock = LK_EXCLUSIVE;
        } else {
                onevp = false;
                invp_lock = LK_SHARED;
        }
        mustclone = false;
        if (onevp || (ap->a_flags & COPY_FILE_RANGE_CLONE) != 0)
                mustclone = true;
relock:
        inoff = *ap->a_inoffp;
        outoff = *ap->a_outoffp;

        /* Lock vnode(s), avoiding risk of deadlock. */
        do {
                mp = NULL;
                error = vn_start_write(outvp, &mp, V_WAIT);
                if (error == 0) {
                        error = vn_lock(outvp, LK_EXCLUSIVE);
                        if (error == 0) {
                                if (onevp)
                                        break;
                                error = vn_lock(invp, invp_lock | LK_NOWAIT);
                                if (error == 0)
                                        break;
                                VOP_UNLOCK(outvp);
                                if (mp != NULL)
                                        vn_finished_write(mp);
                                mp = NULL;
                                error = vn_lock(invp, invp_lock);
                                if (error == 0)
                                        VOP_UNLOCK(invp);
                        }
                }
                if (mp != NULL)
                        vn_finished_write(mp);
        } while (error == 0);
        if (error != 0)
                return (error);

        /*
         * More reasons to avoid nfs copy/clone: not NFSv4.2, explicitly
         * disabled or requires cloning and unable to clone.
         * Only clone if the clone_blksize attribute is supported
         * and the clone_blksize is greater than 0.
         * Alignment of offsets and length will be checked later.
         */
        nmp = VFSTONFS(invp->v_mount);
        np = VTONFS(invp);
        mtx_lock(&nmp->nm_mtx);
        if ((nmp->nm_privflag & NFSMNTP_NOCOPY) != 0)
                mustclone = true;
        if (!NFSHASNFSV4(nmp) || nmp->nm_minorvers < NFSV42_MINORVERSION ||
            (mustclone && (!NFSISSET_ATTRBIT(&np->n_vattr.na_suppattr,
             NFSATTRBIT_CLONEBLKSIZE) || nmp->nm_cloneblksize == 0))) {
                mtx_unlock(&nmp->nm_mtx);
                VOP_UNLOCK(invp);
                if (!onevp)
                        VOP_UNLOCK(outvp);      /* For onevp, same as invp. */
                if (mp != NULL)
                        vn_finished_write(mp);
                goto generic_copy;
        }
        mtx_unlock(&nmp->nm_mtx);

        /*
         * Do the vn_rlimit_fsize() check.  Should this be above the VOP layer?
         */
        io.uio_offset = *ap->a_outoffp;
        io.uio_resid = *ap->a_lenp;
        error = vn_rlimit_fsizex(outvp, &io, 0, &r, ap->a_fsizetd);
        *ap->a_lenp = io.uio_resid;
        /*
         * No need to call vn_rlimit_fsizex_res before return, since the uio is
         * local.
         */

        /*
         * Flush the input file so that the data is up to date before
         * the copy.  Flush writes for the output file so that they
         * do not overwrite the data copied to the output file by the Copy.
         * Set the commit argument for both flushes so that the data is on
         * stable storage before the Copy RPC.  This is done in case the
         * server reboots during the Copy and needs to be redone.
         */
        if (error == 0) {
                invp_obj = invp->v_object;
                if (invp_obj != NULL && vm_object_mightbedirty(invp_obj)) {
                        if (invp_lock != LK_EXCLUSIVE) {
                                KASSERT(!onevp, ("nfs_copy_file_range: "
                                    "invp_lock LK_SHARED for onevp"));
                                invp_lock = LK_EXCLUSIVE;
                                VOP_UNLOCK(invp);
                                VOP_UNLOCK(outvp);
                                if (mp != NULL)
                                        vn_finished_write(mp);
                                goto relock;
                        }
                        vnode_pager_clean_sync(invp);
                }
                error = ncl_flush(invp, MNT_WAIT, curthread, 1, 0);
        }
        if (error == 0)
                error = ncl_vinvalbuf(outvp, V_SAVE, curthread, 0);

        /* Do the actual NFSv4.2 RPC. */
        ret = ret2 = 0;
        len = *ap->a_lenp;
        mtx_lock(&nmp->nm_mtx);
        if ((nmp->nm_privflag & NFSMNTP_NOCONSECUTIVE) == 0)
                consecutive = true;
        else
                consecutive = false;
        mtx_unlock(&nmp->nm_mtx);
        tryoutcred = true;
        must_commit = false;
        toeof = false;

        if (error == 0) {
                vap = &VTONFS(invp)->n_vattr.na_vattr;
                error = VOP_GETATTR(invp, vap, ap->a_incred);
                if (error == 0) {
                        /*
                         * Clip "len" at va_size so that RFC compliant servers
                         * will not reply NFSERR_INVAL.
                         * Setting "len == 0" for the RPC would be preferred,
                         * but some Linux servers do not support that.
                         * If the len is being set to 0, do a Setattr RPC to
                         * set the server's atime.  This behaviour was the
                         * preferred one for the FreeBSD "collective".
                         */
                        if (inoff >= vap->va_size) {
                                *ap->a_lenp = len = 0;
                                if ((nmp->nm_mountp->mnt_flag & MNT_NOATIME) ==
                                    0) {
                                        VATTR_NULL(&va);
                                        va.va_atime.tv_sec = 0;
                                        va.va_atime.tv_nsec = 0;
                                        va.va_vaflags = VA_UTIMES_NULL;
                                        inattrflag = 0;
                                        error = nfsrpc_setattr(invp, &va, NULL,
                                            0, ap->a_incred, curthread,
                                            &innfsva, &inattrflag);
                                        if (inattrflag != 0)
                                                ret = nfscl_loadattrcache(&invp,
                                                    &innfsva, NULL, 0, 1);
                                        if (error == 0 && ret != 0)
                                                error = ret;
                                }
                        } else if (inoff + len >= vap->va_size) {
                                toeof = true;
                                *ap->a_lenp = len = vap->va_size - inoff;
                        }
                } else
                        error = 0;
        }

        /*
         * For cloning, the offsets must be clone blksize aligned and
         * the len must be blksize aligned unless it goes to EOF on
         * the input file.
         */
        tryclone = false;
        if (len > 0) {
                if (error == 0 && NFSISSET_ATTRBIT(&np->n_vattr.na_suppattr,
                    NFSATTRBIT_CLONEBLKSIZE) && nmp->nm_cloneblksize != 0 &&
                    (inoff % nmp->nm_cloneblksize) == 0 &&
                    (outoff % nmp->nm_cloneblksize) == 0 &&
                    (toeof || (len % nmp->nm_cloneblksize) == 0))
                        tryclone = true;
                else if (mustclone)
                        error = ENOSYS;
        }

        /*
         * len will be set to 0 upon a successful Copy RPC.
         * As such, this only loops when the Copy/Clone RPC needs to be retried.
         */
        while (len > 0 && error == 0) {
                inattrflag = outattrflag = 0;
                len2 = len;
                if (tryclone) {
                        if (tryoutcred)
                                error = nfsrpc_clone(invp, ap->a_inoffp, outvp,
                                    ap->a_outoffp, &len2, toeof, &inattrflag,
                                    &innfsva, &outattrflag, &outnfsva,
                                    ap->a_outcred);
                        else
                                error = nfsrpc_clone(invp, ap->a_inoffp, outvp,
                                    ap->a_outoffp, &len2, toeof, &inattrflag,
                                    &innfsva, &outattrflag, &outnfsva,
                                    ap->a_incred);
                } else {
                        if (tryoutcred)
                                error = nfsrpc_copy_file_range(invp,
                                    ap->a_inoffp, outvp, ap->a_outoffp, &len2,
                                    ap->a_flags, &inattrflag, &innfsva,
                                    &outattrflag, &outnfsva,
                                    ap->a_outcred, consecutive, &must_commit);
                        else
                                error = nfsrpc_copy_file_range(invp,
                                    ap->a_inoffp, outvp, ap->a_outoffp, &len2,
                                    ap->a_flags, &inattrflag, &innfsva,
                                    &outattrflag, &outnfsva,
                                    ap->a_incred, consecutive, &must_commit);
                }
                if (inattrflag != 0)
                        ret = nfscl_loadattrcache(&invp, &innfsva, NULL, 0, 1);
                if (outattrflag != 0)
                        ret2 = nfscl_loadattrcache(&outvp, &outnfsva, NULL,
                            1, 1);
                if (error == 0) {
                        if (consecutive == false) {
                                if (len2 == len) {
                                        mtx_lock(&nmp->nm_mtx);
                                        nmp->nm_privflag |=
                                            NFSMNTP_NOCONSECUTIVE;
                                        mtx_unlock(&nmp->nm_mtx);
                                } else
                                        error = NFSERR_OFFLOADNOREQS;
                        }
                        *ap->a_lenp = len2;
                        len = 0;
                        if (len2 > 0 && must_commit && error == 0)
                                error = ncl_commit(outvp, outoff, *ap->a_lenp,
                                    ap->a_outcred, curthread);
                        if (error == 0 && ret != 0)
                                error = ret;
                        if (error == 0 && ret2 != 0)
                                error = ret2;
                } else if (error == NFSERR_OFFLOADNOREQS && consecutive) {
                        /*
                         * Try consecutive == false, which is ok only if all
                         * bytes are copied.
                         * If only some bytes were copied when consecutive
                         * is false, there is no way to know which bytes
                         * still need to be written.
                         */
                        consecutive = false;
                        error = 0;
                } else if (error == NFSERR_ACCES && tryoutcred) {
                        /* Try again with incred. */
                        tryoutcred = false;
                        error = 0;
                } else if (tryclone && error != 0) {
                        if (mustclone) {
                                error = ENOSYS;
                        } else {
                                tryclone = false;
                                error = 0;
                        }
                }
                if (error == NFSERR_STALEWRITEVERF) {
                        /*
                         * Server rebooted, so do it all again.
                         */
                        *ap->a_inoffp = inoff;
                        *ap->a_outoffp = outoff;
                        len = *ap->a_lenp;
                        must_commit = false;
                        error = 0;
                }
        }
        VOP_UNLOCK(invp);
        if (!onevp)
                VOP_UNLOCK(outvp);      /* For onevp, same as invp. */
        if (mp != NULL)
                vn_finished_write(mp);
        if (error == NFSERR_NOTSUPP || error == NFSERR_OFFLOADNOREQS ||
            error == NFSERR_ACCES || error == ENOSYS) {
                /*
                 * Unlike the NFSv4.2 Copy, vn_generic_copy_file_range() can
                 * use a_incred for the read and a_outcred for the write, so
                 * try this for NFSERR_ACCES failures for the Copy.
                 * For NFSERR_NOTSUPP and NFSERR_OFFLOADNOREQS, the Copy can
                 * never succeed, so disable it.
                 */
                if (error != NFSERR_ACCES && error != ENOSYS) {
                        /* Can never do Copy on this mount. */
                        mtx_lock(&nmp->nm_mtx);
                        nmp->nm_privflag |= NFSMNTP_NOCOPY;
                        mtx_unlock(&nmp->nm_mtx);
                }
                *ap->a_inoffp = inoff;
                *ap->a_outoffp = outoff;
                error = vn_generic_copy_file_range(ap->a_invp, ap->a_inoffp,
                    ap->a_outvp, ap->a_outoffp, ap->a_lenp, ap->a_flags,
                    ap->a_incred, ap->a_outcred, ap->a_fsizetd);
        } else if (error != 0)
                *ap->a_lenp = 0;

        if (error != 0)
                error = nfscl_maperr(curthread, error, (uid_t)0, (gid_t)0);
        return (error);
}

/*
 * nfs ioctl call
 */
static int
nfs_ioctl(struct vop_ioctl_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct nfsvattr nfsva;
        struct nfsmount *nmp;
        int attrflag, content, error, ret;
        bool eof = false;                       /* shut up compiler. */

        /* Do the actual NFSv4.2 RPC. */
        switch (ap->a_command) {
        case FIOSEEKDATA:
                content = NFSV4CONTENT_DATA;
                break;
        case FIOSEEKHOLE:
                content = NFSV4CONTENT_HOLE;
                break;
        default:
                return (ENOTTY);
        }

        error = vn_lock(vp, LK_EXCLUSIVE);
        if (error != 0)
                return (EBADF);

        if (vp->v_type != VREG) {
                VOP_UNLOCK(vp);
                return (ENOTTY);
        }
        nmp = VFSTONFS(vp->v_mount);
        if (!NFSHASNFSV4(nmp) || nmp->nm_minorvers < NFSV42_MINORVERSION) {
                VOP_UNLOCK(vp);
                error = vop_stdioctl(ap);
                return (error);
        }

        attrflag = 0;
        if (*((off_t *)ap->a_data) >= VTONFS(vp)->n_size)
                error = ENXIO;
        else {
                /*
                 * Flush all writes, so that the server is up to date.
                 * Although a Commit is not required, the commit argument
                 * is set so that, for a pNFS File/Flexible File Layout
                 * server, the LayoutCommit will be done to ensure the file
                 * size is up to date on the Metadata Server.
                 */

                vnode_pager_clean_sync(vp);
                error = ncl_flush(vp, MNT_WAIT, ap->a_td, 1, 0);
                if (error == 0)
                        error = nfsrpc_seek(vp, (off_t *)ap->a_data, &eof,
                            content, ap->a_cred, &nfsva, &attrflag);
                /* If at eof for FIOSEEKDATA, return ENXIO. */
                if (eof && error == 0 && content == NFSV4CONTENT_DATA)
                        error = ENXIO;
        }
        if (attrflag != 0) {
                ret = nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
                if (error == 0 && ret != 0)
                        error = ret;
        }
        NFSVOPUNLOCK(vp);

        if (error != 0)
                error = ENXIO;
        return (error);
}

/*
 * nfs getextattr call
 */
static int
nfs_getextattr(struct vop_getextattr_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct nfsmount *nmp;
        struct ucred *cred;
        struct thread *td = ap->a_td;
        struct nfsvattr nfsva;
        ssize_t len;
        int attrflag, error, ret;

        nmp = VFSTONFS(vp->v_mount);
        mtx_lock(&nmp->nm_mtx);
        if (!NFSHASNFSV4(nmp) || nmp->nm_minorvers < NFSV42_MINORVERSION ||
            (nmp->nm_privflag & NFSMNTP_NOXATTR) != 0 ||
            ap->a_attrnamespace != EXTATTR_NAMESPACE_USER) {
                mtx_unlock(&nmp->nm_mtx);
                return (EOPNOTSUPP);
        }
        mtx_unlock(&nmp->nm_mtx);

        cred = ap->a_cred;
        if (cred == NULL)
                cred = td->td_ucred;
        /* Do the actual NFSv4.2 Optional Extended Attribute (RFC-8276) RPC. */
        attrflag = 0;
        error = nfsrpc_getextattr(vp, ap->a_name, ap->a_uio, &len, &nfsva,
            &attrflag, cred, td);
        if (attrflag != 0) {
                ret = nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
                if (error == 0 && ret != 0)
                        error = ret;
        }
        if (error == 0 && ap->a_size != NULL)
                *ap->a_size = len;

        switch (error) {
        case NFSERR_NOTSUPP:
        case NFSERR_OPILLEGAL:
                mtx_lock(&nmp->nm_mtx);
                nmp->nm_privflag |= NFSMNTP_NOXATTR;
                mtx_unlock(&nmp->nm_mtx);
                error = EOPNOTSUPP;
                break;
        case NFSERR_NOXATTR:
        case NFSERR_XATTR2BIG:
                error = ENOATTR;
                break;
        default:
                error = nfscl_maperr(td, error, 0, 0);
                break;
        }
        return (error);
}

/*
 * nfs setextattr call
 */
static int
nfs_setextattr(struct vop_setextattr_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct nfsmount *nmp;
        struct ucred *cred;
        struct thread *td = ap->a_td;
        struct nfsvattr nfsva;
        int attrflag, error, ret;

        nmp = VFSTONFS(vp->v_mount);
        mtx_lock(&nmp->nm_mtx);
        if (!NFSHASNFSV4(nmp) || nmp->nm_minorvers < NFSV42_MINORVERSION ||
            (nmp->nm_privflag & NFSMNTP_NOXATTR) != 0 ||
            ap->a_attrnamespace != EXTATTR_NAMESPACE_USER) {
                mtx_unlock(&nmp->nm_mtx);
                return (EOPNOTSUPP);
        }
        mtx_unlock(&nmp->nm_mtx);

        if (ap->a_uio->uio_resid < 0)
                return (EINVAL);
        cred = ap->a_cred;
        if (cred == NULL)
                cred = td->td_ucred;
        /* Do the actual NFSv4.2 Optional Extended Attribute (RFC-8276) RPC. */
        attrflag = 0;
        error = nfsrpc_setextattr(vp, ap->a_name, ap->a_uio, &nfsva,
            &attrflag, cred, td);
        if (attrflag != 0) {
                ret = nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
                if (error == 0 && ret != 0)
                        error = ret;
        }

        switch (error) {
        case NFSERR_NOTSUPP:
        case NFSERR_OPILLEGAL:
                mtx_lock(&nmp->nm_mtx);
                nmp->nm_privflag |= NFSMNTP_NOXATTR;
                mtx_unlock(&nmp->nm_mtx);
                error = EOPNOTSUPP;
                break;
        case NFSERR_NOXATTR:
        case NFSERR_XATTR2BIG:
                error = ENOATTR;
                break;
        default:
                error = nfscl_maperr(td, error, 0, 0);
                break;
        }
        return (error);
}

/*
 * nfs listextattr call
 */
static int
nfs_listextattr(struct vop_listextattr_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct nfsmount *nmp;
        struct ucred *cred;
        struct thread *td = ap->a_td;
        struct nfsvattr nfsva;
        size_t len, len2;
        uint64_t cookie;
        int attrflag, error, ret;
        bool eof;

        nmp = VFSTONFS(vp->v_mount);
        mtx_lock(&nmp->nm_mtx);
        if (!NFSHASNFSV4(nmp) || nmp->nm_minorvers < NFSV42_MINORVERSION ||
            (nmp->nm_privflag & NFSMNTP_NOXATTR) != 0 ||
            ap->a_attrnamespace != EXTATTR_NAMESPACE_USER) {
                mtx_unlock(&nmp->nm_mtx);
                return (EOPNOTSUPP);
        }
        mtx_unlock(&nmp->nm_mtx);

        cred = ap->a_cred;
        if (cred == NULL)
                cred = td->td_ucred;

        /* Loop around doing List Extended Attribute RPCs. */
        eof = false;
        cookie = 0;
        len2 = 0;
        error = 0;
        while (!eof && error == 0) {
                len = nmp->nm_rsize;
                attrflag = 0;
                error = nfsrpc_listextattr(vp, &cookie, ap->a_uio, &len, &eof,
                    &nfsva, &attrflag, cred, td);
                if (attrflag != 0) {
                        ret = nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
                        if (error == 0 && ret != 0)
                                error = ret;
                }
                if (error == 0) {
                        len2 += len;
                        if (len2 > SSIZE_MAX)
                                error = ENOATTR;
                }
        }
        if (error == 0 && ap->a_size != NULL)
                *ap->a_size = len2;

        switch (error) {
        case NFSERR_NOTSUPP:
        case NFSERR_OPILLEGAL:
                mtx_lock(&nmp->nm_mtx);
                nmp->nm_privflag |= NFSMNTP_NOXATTR;
                mtx_unlock(&nmp->nm_mtx);
                error = EOPNOTSUPP;
                break;
        case NFSERR_NOXATTR:
        case NFSERR_XATTR2BIG:
                error = ENOATTR;
                break;
        default:
                error = nfscl_maperr(td, error, 0, 0);
                break;
        }
        return (error);
}

/*
 * nfs setextattr call
 */
static int
nfs_deleteextattr(struct vop_deleteextattr_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct nfsmount *nmp;
        struct nfsvattr nfsva;
        int attrflag, error, ret;

        nmp = VFSTONFS(vp->v_mount);
        mtx_lock(&nmp->nm_mtx);
        if (!NFSHASNFSV4(nmp) || nmp->nm_minorvers < NFSV42_MINORVERSION ||
            (nmp->nm_privflag & NFSMNTP_NOXATTR) != 0 ||
            ap->a_attrnamespace != EXTATTR_NAMESPACE_USER) {
                mtx_unlock(&nmp->nm_mtx);
                return (EOPNOTSUPP);
        }
        mtx_unlock(&nmp->nm_mtx);

        /* Do the actual NFSv4.2 Optional Extended Attribute (RFC-8276) RPC. */
        attrflag = 0;
        error = nfsrpc_rmextattr(vp, ap->a_name, &nfsva, &attrflag, ap->a_cred,
            ap->a_td);
        if (attrflag != 0) {
                ret = nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
                if (error == 0 && ret != 0)
                        error = ret;
        }

        switch (error) {
        case NFSERR_NOTSUPP:
        case NFSERR_OPILLEGAL:
                mtx_lock(&nmp->nm_mtx);
                nmp->nm_privflag |= NFSMNTP_NOXATTR;
                mtx_unlock(&nmp->nm_mtx);
                error = EOPNOTSUPP;
                break;
        case NFSERR_NOXATTR:
        case NFSERR_XATTR2BIG:
                error = ENOATTR;
                break;
        default:
                error = nfscl_maperr(ap->a_td, error, 0, 0);
                break;
        }
        return (error);
}

/*
 * Return POSIX pathconf information applicable to nfs filesystems.
 */
static int
nfs_pathconf(struct vop_pathconf_args *ap)
{
        struct nfsv3_pathconf pc;
        struct nfsvattr nfsva;
        struct vnode *vp = ap->a_vp;
        struct nfsmount *nmp;
        struct thread *td = curthread;
        off_t off;
        uint32_t clone_blksize;
        bool eof, has_namedattr, named_enabled;
        int attrflag, error;
        struct nfsnode *np;
        uint32_t trueform;

        nmp = VFSTONFS(vp->v_mount);
        np = VTONFS(vp);
        named_enabled = false;
        has_namedattr = false;
        clone_blksize = 0;
        if ((NFS_ISV34(vp) && (ap->a_name == _PC_LINK_MAX ||
            ap->a_name == _PC_NAME_MAX || ap->a_name == _PC_CHOWN_RESTRICTED ||
            ap->a_name == _PC_NO_TRUNC ||
            ap->a_name == _PC_CASE_INSENSITIVE)) ||
            (NFS_ISV4(vp) && (ap->a_name == _PC_ACL_NFS4 ||
             ap->a_name == _PC_HAS_NAMEDATTR ||
             ap->a_name == _PC_CLONE_BLKSIZE ||
             ap->a_name == _PC_ACL_EXTENDED))) {
                /*
                 * Since only the above 5 a_names are returned by the NFSv3
                 * Pathconf RPC, there is no point in doing it for others.
                 * For NFSv4, the Pathconf RPC (actually a Getattr Op.) can
                 * be used for _PC_ACL_NFS4, _PC_HAS_NAMEDATTR,
                 * and _PC_ACL_EXTENDED as well.
                 */
                trueform = UINT32_MAX;
                error = nfsrpc_pathconf(vp, &pc, &has_namedattr, &clone_blksize,
                    td->td_ucred, td, &nfsva, &attrflag, &trueform);
                if (attrflag != 0)
                        (void) nfscl_loadattrcache(&vp, &nfsva, NULL, 0, 1);
                if (error != 0)
                        return (error);
        } else if (NFS_ISV4(vp) && ap->a_name == _PC_NAMEDATTR_ENABLED &&
            (np->n_flag & NNAMEDNOTSUPP) == 0) {
                struct nfsfh *nfhp;

                error = nfsrpc_openattr(nmp, vp, np->n_fhp->nfh_fh,
                    np->n_fhp->nfh_len, false, td->td_ucred, td, &nfsva, &nfhp,
                    &attrflag);
                named_enabled = true;
                if (error == 0) {
                        free(nfhp, M_NFSFH);
                } else if (error == NFSERR_NOTSUPP) {
                        named_enabled = false;
                        NFSLOCKNODE(np);
                        np->n_flag |= NNAMEDNOTSUPP;
                        NFSUNLOCKNODE(np);
                }
                error = 0;
        } else {
                /*
                 * For NFSv2 (or NFSv3 when not one of the above 4 a_names),
                 * just fake them.
                 */
                pc.pc_linkmax = NFS_LINK_MAX;
                pc.pc_namemax = NFS_MAXNAMLEN;
                pc.pc_notrunc = 1;
                pc.pc_chownrestricted = 1;
                pc.pc_caseinsensitive = 0;
                pc.pc_casepreserving = 1;
                error = 0;
        }
        switch (ap->a_name) {
        case _PC_LINK_MAX:
#ifdef _LP64
                *ap->a_retval = pc.pc_linkmax;
#else
                *ap->a_retval = MIN(LONG_MAX, pc.pc_linkmax);
#endif
                break;
        case _PC_NAME_MAX:
                *ap->a_retval = pc.pc_namemax;
                break;
        case _PC_PIPE_BUF:
                if (ap->a_vp->v_type == VDIR || ap->a_vp->v_type == VFIFO)
                        *ap->a_retval = PIPE_BUF;
                else
                        error = EINVAL;
                break;
        case _PC_CHOWN_RESTRICTED:
                *ap->a_retval = pc.pc_chownrestricted;
                break;
        case _PC_NO_TRUNC:
                *ap->a_retval = pc.pc_notrunc;
                break;
        case _PC_ACL_NFS4:
                if (NFS_ISV4(vp) && nfsrv_useacl != 0 && attrflag != 0 &&
                    NFSISSET_ATTRBIT(&nfsva.na_suppattr, NFSATTRBIT_ACL) &&
                    (trueform == NFSV4_ACL_MODEL_NFS4 ||
                     trueform == UINT32_MAX))
                        *ap->a_retval = 1;
                else
                        *ap->a_retval = 0;
                break;
        case _PC_ACL_EXTENDED:
                if (NFS_ISV4(vp) && nfsrv_useacl != 0 && attrflag != 0 &&
                    NFSISSET_ATTRBIT(&nfsva.na_suppattr,
                    NFSATTRBIT_POSIXACCESSACL) &&
                    NFSISSET_ATTRBIT(&nfsva.na_suppattr,
                    NFSATTRBIT_POSIXDEFAULTACL) &&
                    trueform == NFSV4_ACL_MODEL_POSIX_DRAFT)
                        *ap->a_retval = 1;
                else
                        *ap->a_retval = 0;
                break;
        case _PC_ACL_PATH_MAX:
                if (NFS_ISV4(vp))
                        *ap->a_retval = ACL_MAX_ENTRIES;
                else
                        *ap->a_retval = 3;
                break;
        case _PC_PRIO_IO:
                *ap->a_retval = 0;
                break;
        case _PC_SYNC_IO:
                *ap->a_retval = 0;
                break;
        case _PC_ALLOC_SIZE_MIN:
                *ap->a_retval = vp->v_mount->mnt_stat.f_bsize;
                break;
        case _PC_FILESIZEBITS:
                if (NFS_ISV34(vp))
                        *ap->a_retval = 64;
                else
                        *ap->a_retval = 32;
                break;
        case _PC_REC_INCR_XFER_SIZE:
                *ap->a_retval = vp->v_mount->mnt_stat.f_iosize;
                break;
        case _PC_REC_MAX_XFER_SIZE:
                *ap->a_retval = -1; /* means ``unlimited'' */
                break;
        case _PC_REC_MIN_XFER_SIZE:
                *ap->a_retval = vp->v_mount->mnt_stat.f_iosize;
                break;
        case _PC_REC_XFER_ALIGN:
                *ap->a_retval = PAGE_SIZE;
                break;
        case _PC_SYMLINK_MAX:
                *ap->a_retval = NFS_MAXPATHLEN;
                break;
        case _PC_MIN_HOLE_SIZE:
                /* Only some NFSv4.2 servers support Seek for Holes. */
                *ap->a_retval = 0;
                if (NFS_ISV4(vp) && nmp->nm_minorvers == NFSV42_MINORVERSION) {
                        /*
                         * NFSv4.2 doesn't have an attribute for hole size,
                         * so all we can do is see if the Seek operation is
                         * supported and then use f_iosize as a "best guess".
                         */
                        mtx_lock(&nmp->nm_mtx);
                        if ((nmp->nm_privflag & NFSMNTP_SEEKTESTED) == 0) {
                                mtx_unlock(&nmp->nm_mtx);
                                off = 0;
                                attrflag = 0;
                                error = nfsrpc_seek(vp, &off, &eof,
                                    NFSV4CONTENT_HOLE, td->td_ucred, &nfsva,
                                    &attrflag);
                                if (attrflag != 0)
                                        (void) nfscl_loadattrcache(&vp, &nfsva,
                                            NULL, 0, 1);
                                mtx_lock(&nmp->nm_mtx);
                                if (error == NFSERR_NOTSUPP)
                                        nmp->nm_privflag |= NFSMNTP_SEEKTESTED;
                                else
                                        nmp->nm_privflag |= NFSMNTP_SEEKTESTED |
                                            NFSMNTP_SEEK;
                                error = 0;
                        }
                        if ((nmp->nm_privflag & NFSMNTP_SEEK) != 0)
                                *ap->a_retval = vp->v_mount->mnt_stat.f_iosize;
                        mtx_unlock(&nmp->nm_mtx);
                }
                break;
        case _PC_NAMEDATTR_ENABLED:
                if (named_enabled)
                        *ap->a_retval = 1;
                else
                        *ap->a_retval = 0;
                break;
        case _PC_HAS_NAMEDATTR:
                if (has_namedattr)
                        *ap->a_retval = 1;
                else
                        *ap->a_retval = 0;
                break;
        case _PC_HAS_HIDDENSYSTEM:
                if (NFS_ISV4(vp) && NFSISSET_ATTRBIT(&np->n_vattr.na_suppattr,
                    NFSATTRBIT_ARCHIVE) &&
                    NFSISSET_ATTRBIT(&np->n_vattr.na_suppattr,
                    NFSATTRBIT_HIDDEN) &&
                    NFSISSET_ATTRBIT(&np->n_vattr.na_suppattr,
                    NFSATTRBIT_SYSTEM))
                        *ap->a_retval = 1;
                else
                        *ap->a_retval = 0;
                break;
        case _PC_CLONE_BLKSIZE:
                *ap->a_retval = clone_blksize;
                break;
        case _PC_CASE_INSENSITIVE:
                *ap->a_retval = pc.pc_caseinsensitive;
                break;

        default:
                error = vop_stdpathconf(ap);
                break;
        }
        return (error);
}