xnu-2050.48.11.tar.gz

[apple/xnu.git] / bsd / nfs / nfs_node.c

/*
 * Copyright (c) 2000-2013 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)nfs_node.c  8.6 (Berkeley) 5/22/95
 * FreeBSD-Id: nfs_node.c,v 1.22 1997/10/28 14:06:20 bde Exp $
 */


#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/kauth.h>
#include <sys/mount_internal.h>
#include <sys/vnode_internal.h>
#include <sys/vnode.h>
#include <sys/ubc.h>
#include <sys/malloc.h>
#include <sys/fcntl.h>
#include <sys/time.h>

#include <nfs/rpcv2.h>
#include <nfs/nfsproto.h>
#include <nfs/nfs.h>
#include <nfs/nfsnode.h>
#include <nfs/nfs_gss.h>
#include <nfs/nfsmount.h>

#define NFSNOHASH(fhsum) \
        (&nfsnodehashtbl[(fhsum) & nfsnodehash])
static LIST_HEAD(nfsnodehashhead, nfsnode) *nfsnodehashtbl;
static u_long nfsnodehash;

static lck_grp_t *nfs_node_hash_lck_grp;
static lck_grp_t *nfs_node_lck_grp;
static lck_grp_t *nfs_data_lck_grp;
lck_mtx_t *nfs_node_hash_mutex;

/*
 * Initialize hash links for nfsnodes
 * and build nfsnode free list.
 */
void
nfs_nhinit(void)
{
        nfs_node_hash_lck_grp = lck_grp_alloc_init("nfs_node_hash", LCK_GRP_ATTR_NULL);
        nfs_node_hash_mutex = lck_mtx_alloc_init(nfs_node_hash_lck_grp, LCK_ATTR_NULL);
        nfs_node_lck_grp = lck_grp_alloc_init("nfs_node", LCK_GRP_ATTR_NULL);
        nfs_data_lck_grp = lck_grp_alloc_init("nfs_data", LCK_GRP_ATTR_NULL);
}

void
nfs_nhinit_finish(void)
{
        lck_mtx_lock(nfs_node_hash_mutex);
        if (!nfsnodehashtbl)
                nfsnodehashtbl = hashinit(desiredvnodes, M_NFSNODE, &nfsnodehash);
        lck_mtx_unlock(nfs_node_hash_mutex);
}

/*
 * Compute an entry in the NFS hash table structure
 */
u_long
nfs_hash(u_char *fhp, int fhsize)
{
        u_long fhsum;
        int i;

        fhsum = 0;
        for (i = 0; i < fhsize; i++)
                fhsum += *fhp++;
        return (fhsum);
}

        
int nfs_case_insensitive(mount_t);

int
nfs_case_insensitive(mount_t mp)
{
        struct nfsmount *nmp = VFSTONFS(mp);
        int answer = 0;
        int skip = 0;
        
        if (nmp == NULL) {
                return (0);
        }
        
        if (nmp->nm_vers == NFS_VER2) {
                /* V2 has no way to know */
                return (0);
        }

        lck_mtx_lock(&nmp->nm_lock);
        if (nmp->nm_vers == NFS_VER3) {
                if (!(nmp->nm_state & NFSSTA_GOTPATHCONF)) {
                        /* We're holding the node lock so we just return 
                         * with answer as case sensitive. Is very rare
                         * for file systems not to be homogenous w.r.t. pathconf
                         */
                        skip = 1;
                } 
        } else if (!(nmp->nm_fsattr.nfsa_flags & NFS_FSFLAG_HOMOGENEOUS)) {
                /* no pathconf info cached */
                skip = 1;
        }

        if (!skip && NFS_BITMAP_ISSET(nmp->nm_fsattr.nfsa_bitmap, NFS_FATTR_CASE_INSENSITIVE))
                answer = 1;

        lck_mtx_unlock(&nmp->nm_lock);

        return (answer);
}

        
/*
 * Look up a vnode/nfsnode by file handle.
 * Callers must check for mount points!!
 * In all cases, a pointer to a
 * nfsnode structure is returned.
 */
int
nfs_nget(
        mount_t mp,
        nfsnode_t dnp,
        struct componentname *cnp,
        u_char *fhp,
        int fhsize,
        struct nfs_vattr *nvap,
        u_int64_t *xidp,
        uint32_t auth,
        int flags,
        nfsnode_t *npp)
{
        nfsnode_t np;
        struct nfsnodehashhead *nhpp;
        vnode_t vp;
        int error, nfsvers;
        mount_t mp2;
        struct vnode_fsparam vfsp;
        uint32_t vid;

        FSDBG_TOP(263, mp, dnp, flags, npp);

        /* Check for unmount in progress */
        if (!mp || (mp->mnt_kern_flag & MNTK_FRCUNMOUNT)) {
                *npp = NULL;
                error = ENXIO;
                FSDBG_BOT(263, mp, dnp, 0xd1e, error);
                return (error);
        }
        nfsvers = VFSTONFS(mp)->nm_vers;

        nhpp = NFSNOHASH(nfs_hash(fhp, fhsize));
loop:
        lck_mtx_lock(nfs_node_hash_mutex);
        for (np = nhpp->lh_first; np != 0; np = np->n_hash.le_next) {
                mp2 = (np->n_hflag & NHINIT) ? np->n_mount : NFSTOMP(np);
                if (mp != mp2 || np->n_fhsize != fhsize ||
                    bcmp(fhp, np->n_fhp, fhsize))
                        continue;
                if (nvap && (nvap->nva_flags & NFS_FFLAG_TRIGGER_REFERRAL) &&
                    cnp && (cnp->cn_namelen > (fhsize - (int)sizeof(dnp)))) {
                        /* The name was too long to fit in the file handle.  Check it against the node's name. */
                        int namecmp = 0;
                        const char *vname = vnode_getname(NFSTOV(np));
                        if (vname) {
                                if (cnp->cn_namelen != (int)strlen(vname))
                                        namecmp = 1;
                                else
                                        namecmp = strncmp(vname, cnp->cn_nameptr, cnp->cn_namelen);
                                vnode_putname(vname);
                        }
                        if (namecmp)  /* full name didn't match */
                                continue;
                }
                FSDBG(263, dnp, np, np->n_flag, 0xcace0000);
                /* if the node is locked, sleep on it */
                if ((np->n_hflag & NHLOCKED) && !(flags & NG_NOCREATE)) {
                        np->n_hflag |= NHLOCKWANT;
                        FSDBG(263, dnp, np, np->n_flag, 0xcace2222);
                        msleep(np, nfs_node_hash_mutex, PDROP | PINOD, "nfs_nget", NULL);
                        FSDBG(263, dnp, np, np->n_flag, 0xcace3333);
                        goto loop;
                }
                vp = NFSTOV(np);
                vid = vnode_vid(vp);
                lck_mtx_unlock(nfs_node_hash_mutex);
                if ((error = vnode_getwithvid(vp, vid))) {
                        /*
                         * If vnode is being reclaimed or has already
                         * changed identity, no need to wait.
                         */
                        FSDBG_BOT(263, dnp, *npp, 0xcace0d1e, error);
                        return (error);
                }
                if ((error = nfs_node_lock(np))) {
                        /* this only fails if the node is now unhashed */
                        /* so let's see if we can find/create it again */
                        FSDBG(263, dnp, *npp, 0xcaced1e2, error);
                        vnode_put(vp);
                        if (flags & NG_NOCREATE) {
                                *npp = 0;
                                FSDBG_BOT(263, dnp, *npp, 0xcaced1e0, ENOENT);
                                return (ENOENT);
                        }
                        goto loop;
                }
                /* update attributes */
                if (nvap)
                        error = nfs_loadattrcache(np, nvap, xidp, 0);
                if (error) {
                        nfs_node_unlock(np);
                        vnode_put(vp);
                } else {
                        if (dnp && cnp && (flags & NG_MAKEENTRY))
                                cache_enter(NFSTOV(dnp), vp, cnp);
                        /*
                         * Update the vnode if the name/and or the parent has
                         * changed. We need to do this so that if getattrlist is
                         * called asking for ATTR_CMN_NAME, that the "most"
                         * correct name is being returned if we're not making an
                         * entry. In addition for monitored vnodes we need to
                         * kick the vnode out of the name cache. We do this so
                         * that if there are hard links in the same directory
                         * the link will not be found and a lookup will get us
                         * here to return the name of the current link. In
                         * addition by removing the name from the name cache the
                         * old name will not be found after a rename done on
                         * another client or the server.  The principle reason
                         * to do this is because Finder is asking for
                         * notifications on a directory.  The directory changes,
                         * Finder gets notified, reads the directory (which we
                         * have purged) and for each entry returned calls
                         * getattrlist with the name returned from
                         * readdir. gettattrlist has to call namei/lookup to
                         * resolve the name, because its not in the cache we end
                         * up here. We need to update the name so Finder will
                         * get the name it called us with.
                         *
                         * We had an imperfect solution with respect to case
                         * sensitivity.  There is a test that is run in
                         * FileBuster that does renames from some name to
                         * another name differing only in case. It then reads
                         * the directory looking for the new name, after it
                         * finds that new name, it ask gettattrlist to verify
                         * that the name is the new name.  Usually that works,
                         * but renames generate fsevents and fseventsd will do a
                         * lookup on the name via lstat. Since that test renames
                         * old name to new name back and forth there is a race
                         * that an fsevent will be behind and will access the
                         * file by the old name, on a case insensitive file
                         * system that will work. Problem is if we do a case
                         * sensitive compare, we're going to change the name,
                         * which the test's getattrlist verification step is
                         * going to fail. So we will check the case sensitivity
                         * of the file system and do the appropriate compare. In
                         * a rare instance for non homogeneous file systems
                         * w.r.t. pathconf we will use case sensitive compares.
                         * That could break if the file system is actually case
                         * insensitive.
                         *
                         * Note that V2 does not know the case, so we just
                         * assume case sensitivity. 
                         *
                         * This is clearly not perfect due to races, but this is
                         * as good as its going to get. You can defeat the
                         * handling of hard links simply by doing:
                         *
                         *      while :; do ls -l > /dev/null; done
                         *
                         * in a terminal window. Even a single ls -l can cause a
                         * race.
                         *
                         * <rant>What we really need is for the caller, that
                         * knows the name being used is valid since it got it
                         * from a readdir to use that name and not ask for the
                         * ATTR_CMN_NAME</rant>
                         */
                        if (dnp && cnp && (vp != NFSTOV(dnp))) {
                                int update_flags = vnode_ismonitored((NFSTOV(dnp))) ? VNODE_UPDATE_CACHE : 0;
                                int (*cmp)(const char *s1, const char *s2, size_t n);

                                cmp = nfs_case_insensitive(mp) ? strncasecmp : strncmp;

                                if (vp->v_name && cnp->cn_namelen && (*cmp)(cnp->cn_nameptr, vp->v_name, cnp->cn_namelen))
                                        update_flags |= VNODE_UPDATE_NAME;
                                if ((vp->v_name == NULL && cnp->cn_namelen != 0) || (vp->v_name != NULL && cnp->cn_namelen == 0))
                                        update_flags |= VNODE_UPDATE_NAME;
                                if (vnode_parent(vp) != NFSTOV(dnp))
                                        update_flags |= VNODE_UPDATE_PARENT;
                                if (update_flags)
                                        vnode_update_identity(vp, NFSTOV(dnp), cnp->cn_nameptr, cnp->cn_namelen, 0, update_flags);
                        }

                        *npp = np;
                }
                FSDBG_BOT(263, dnp, *npp, 0xcace0000, error);
                return(error);
        }

        FSDBG(263, mp, dnp, npp, 0xaaaaaaaa);

        if (flags & NG_NOCREATE) {
                lck_mtx_unlock(nfs_node_hash_mutex);
                *npp = 0;
                FSDBG_BOT(263, dnp, *npp, 0x80000001, ENOENT);
                return (ENOENT);
        }

        /*
         * allocate and initialize nfsnode and stick it in the hash
         * before calling getnewvnode().  Anyone finding it in the
         * hash before initialization is complete will wait for it.
         */
        MALLOC_ZONE(np, nfsnode_t, sizeof *np, M_NFSNODE, M_WAITOK);
        if (!np) {
                lck_mtx_unlock(nfs_node_hash_mutex);
                *npp = 0;
                FSDBG_BOT(263, dnp, *npp, 0x80000001, ENOMEM);
                return (ENOMEM);
        }
        bzero(np, sizeof *np);
        np->n_hflag |= (NHINIT | NHLOCKED);
        np->n_mount = mp;
        np->n_auth = auth;
        TAILQ_INIT(&np->n_opens);
        TAILQ_INIT(&np->n_lock_owners);
        TAILQ_INIT(&np->n_locks);
        np->n_dlink.tqe_next = NFSNOLIST;
        np->n_dreturn.tqe_next = NFSNOLIST;
        np->n_monlink.le_next = NFSNOLIST;

        /* ugh... need to keep track of ".zfs" directories to workaround server bugs */
        if ((nvap->nva_type == VDIR) && cnp && (cnp->cn_namelen == 4) &&
            (cnp->cn_nameptr[0] == '.') && (cnp->cn_nameptr[1] == 'z') &&
            (cnp->cn_nameptr[2] == 'f') && (cnp->cn_nameptr[3] == 's'))
                np->n_flag |= NISDOTZFS;
        if (dnp && (dnp->n_flag & NISDOTZFS))
                np->n_flag |= NISDOTZFSCHILD;

        if (dnp && cnp && ((cnp->cn_namelen != 2) ||
            (cnp->cn_nameptr[0] != '.') || (cnp->cn_nameptr[1] != '.'))) {
                vnode_t dvp = NFSTOV(dnp);
                if (!vnode_get(dvp)) {
                        if (!vnode_ref(dvp))
                                np->n_parent = dvp;
                        vnode_put(dvp);
                }
        }

        /* setup node's file handle */
        if (fhsize > NFS_SMALLFH) {
                MALLOC_ZONE(np->n_fhp, u_char *,
                                fhsize, M_NFSBIGFH, M_WAITOK);
                if (!np->n_fhp) {
                        lck_mtx_unlock(nfs_node_hash_mutex);
                        FREE_ZONE(np, sizeof *np, M_NFSNODE);
                        *npp = 0;
                        FSDBG_BOT(263, dnp, *npp, 0x80000002, ENOMEM);
                        return (ENOMEM);
                }
        } else {
                np->n_fhp = &np->n_fh[0];
        }
        bcopy(fhp, np->n_fhp, fhsize);
        np->n_fhsize = fhsize;

        /* Insert the nfsnode in the hash queue for its new file handle */
        LIST_INSERT_HEAD(nhpp, np, n_hash);
        np->n_hflag |= NHHASHED;
        FSDBG(266, 0, np, np->n_flag, np->n_hflag);

        /* lock the new nfsnode */
        lck_mtx_init(&np->n_lock, nfs_node_lck_grp, LCK_ATTR_NULL);
        lck_rw_init(&np->n_datalock, nfs_data_lck_grp, LCK_ATTR_NULL);
        lck_mtx_init(&np->n_openlock, nfs_open_grp, LCK_ATTR_NULL);
        lck_mtx_lock(&np->n_lock);

        /* release lock on hash table */
        lck_mtx_unlock(nfs_node_hash_mutex);

        /* do initial loading of attributes */
        NACLINVALIDATE(np);
        NACCESSINVALIDATE(np);
        error = nfs_loadattrcache(np, nvap, xidp, 1);
        if (error) {
                FSDBG(266, 0, np, np->n_flag, 0xb1eb1e);
                nfs_node_unlock(np);
                lck_mtx_lock(nfs_node_hash_mutex);
                LIST_REMOVE(np, n_hash);
                np->n_hflag &= ~(NHHASHED|NHINIT|NHLOCKED);
                if (np->n_hflag & NHLOCKWANT) {
                        np->n_hflag &= ~NHLOCKWANT;
                        wakeup(np);
                }
                lck_mtx_unlock(nfs_node_hash_mutex);
                if (np->n_parent) {
                        if (!vnode_get(np->n_parent)) {
                                vnode_rele(np->n_parent);
                                vnode_put(np->n_parent);
                        }
                        np->n_parent = NULL;
                }
                lck_mtx_destroy(&np->n_lock, nfs_node_lck_grp);
                lck_rw_destroy(&np->n_datalock, nfs_data_lck_grp);
                lck_mtx_destroy(&np->n_openlock, nfs_open_grp);
                if (np->n_fhsize > NFS_SMALLFH)
                        FREE_ZONE(np->n_fhp, np->n_fhsize, M_NFSBIGFH);
                FREE_ZONE(np, sizeof *np, M_NFSNODE);
                *npp = 0;
                FSDBG_BOT(263, dnp, *npp, 0x80000003, error);
                return (error);
        }
        NFS_CHANGED_UPDATE(nfsvers, np, nvap);
        if (nvap->nva_type == VDIR)
                NFS_CHANGED_UPDATE_NC(nfsvers, np, nvap);

        /* now, attempt to get a new vnode */
        vfsp.vnfs_mp = mp;
        vfsp.vnfs_vtype = nvap->nva_type;
        vfsp.vnfs_str = "nfs";
        vfsp.vnfs_dvp = dnp ? NFSTOV(dnp) : NULL;
        vfsp.vnfs_fsnode = np;
        if (nfsvers == NFS_VER4) {
#if FIFO
                if (nvap->nva_type == VFIFO)
                        vfsp.vnfs_vops = fifo_nfsv4nodeop_p;
                else
#endif /* FIFO */
                if (nvap->nva_type == VBLK || nvap->nva_type == VCHR)
                        vfsp.vnfs_vops = spec_nfsv4nodeop_p;
                else
                        vfsp.vnfs_vops = nfsv4_vnodeop_p;
        } else {
#if FIFO
                if (nvap->nva_type == VFIFO)
                        vfsp.vnfs_vops = fifo_nfsv2nodeop_p;
                else
#endif /* FIFO */
                if (nvap->nva_type == VBLK || nvap->nva_type == VCHR)
                        vfsp.vnfs_vops = spec_nfsv2nodeop_p;
                else
                        vfsp.vnfs_vops = nfsv2_vnodeop_p;
        }
        vfsp.vnfs_markroot = (flags & NG_MARKROOT) ? 1 : 0;
        vfsp.vnfs_marksystem = 0;
        vfsp.vnfs_rdev = 0;
        vfsp.vnfs_filesize = nvap->nva_size;
        vfsp.vnfs_cnp = cnp;
        vfsp.vnfs_flags = VNFS_ADDFSREF;
        if (!dnp || !cnp || !(flags & NG_MAKEENTRY))
                vfsp.vnfs_flags |= VNFS_NOCACHE;

#if CONFIG_TRIGGERS
        if ((nfsvers >= NFS_VER4) && (nvap->nva_type == VDIR) && (np->n_vattr.nva_flags & NFS_FFLAG_TRIGGER)) {
                struct vnode_trigger_param vtp;
                bzero(&vtp, sizeof(vtp));
                bcopy(&vfsp, &vtp.vnt_params, sizeof(vfsp));
                vtp.vnt_resolve_func = nfs_mirror_mount_trigger_resolve;
                vtp.vnt_unresolve_func = nfs_mirror_mount_trigger_unresolve;
                vtp.vnt_rearm_func = nfs_mirror_mount_trigger_rearm;
                vtp.vnt_flags = VNT_AUTO_REARM;
                error = vnode_create(VNCREATE_TRIGGER, VNCREATE_TRIGGER_SIZE, &vtp, &np->n_vnode);
        } else
#endif
        {
                error = vnode_create(VNCREATE_FLAVOR, VCREATESIZE, &vfsp, &np->n_vnode);
        }
        if (error) {
                FSDBG(266, 0, np, np->n_flag, 0xb1eb1e);
                nfs_node_unlock(np);
                lck_mtx_lock(nfs_node_hash_mutex);
                LIST_REMOVE(np, n_hash);
                np->n_hflag &= ~(NHHASHED|NHINIT|NHLOCKED);
                if (np->n_hflag & NHLOCKWANT) {
                        np->n_hflag &= ~NHLOCKWANT;
                        wakeup(np);
                }
                lck_mtx_unlock(nfs_node_hash_mutex);
                if (np->n_parent) {
                        if (!vnode_get(np->n_parent)) {
                                vnode_rele(np->n_parent);
                                vnode_put(np->n_parent);
                        }
                        np->n_parent = NULL;
                }
                lck_mtx_destroy(&np->n_lock, nfs_node_lck_grp);
                lck_rw_destroy(&np->n_datalock, nfs_data_lck_grp);
                lck_mtx_destroy(&np->n_openlock, nfs_open_grp);
                if (np->n_fhsize > NFS_SMALLFH)
                        FREE_ZONE(np->n_fhp, np->n_fhsize, M_NFSBIGFH);
                FREE_ZONE(np, sizeof *np, M_NFSNODE);
                *npp = 0;
                FSDBG_BOT(263, dnp, *npp, 0x80000004, error);
                return (error);
        }
        vp = np->n_vnode;
        vnode_settag(vp, VT_NFS);
        /* node is now initialized */

        /* check if anyone's waiting on this node */
        lck_mtx_lock(nfs_node_hash_mutex);
        np->n_hflag &= ~(NHINIT|NHLOCKED);
        if (np->n_hflag & NHLOCKWANT) {
                np->n_hflag &= ~NHLOCKWANT;
                wakeup(np);
        }
        lck_mtx_unlock(nfs_node_hash_mutex);

        *npp = np;

        FSDBG_BOT(263, dnp, vp, *npp, error);
        return (error);
}


int
nfs_vnop_inactive(ap)
        struct vnop_inactive_args /* {
                struct vnodeop_desc *a_desc;
                vnode_t a_vp;
                vfs_context_t a_context;
        } */ *ap;
{
        vnode_t vp = ap->a_vp;
        vfs_context_t ctx = ap->a_context;
        nfsnode_t np = VTONFS(ap->a_vp);
        struct nfs_sillyrename *nsp;
        struct nfs_vattr nvattr;
        int unhash, attrerr, busyerror, error, inuse, busied, force;
        struct nfs_open_file *nofp;
        struct componentname cn;
        struct nfsmount *nmp = NFSTONMP(np);
        mount_t mp = vnode_mount(vp);

restart:
        force = (!mp || (mp->mnt_kern_flag & MNTK_FRCUNMOUNT));
        error = 0;
        inuse = (nfs_mount_state_in_use_start(nmp, NULL) == 0);

        /* There shouldn't be any open or lock state at this point */
        lck_mtx_lock(&np->n_openlock);
        if (np->n_openrefcnt && !force)
                NP(np, "nfs_vnop_inactive: still open: %d", np->n_openrefcnt);
        TAILQ_FOREACH(nofp, &np->n_opens, nof_link) {
                lck_mtx_lock(&nofp->nof_lock);
                if (nofp->nof_flags & NFS_OPEN_FILE_BUSY) {
                        if (!force)
                                NP(np, "nfs_vnop_inactive: open file busy");
                        busied = 0;
                } else {
                        nofp->nof_flags |= NFS_OPEN_FILE_BUSY;
                        busied = 1;
                }
                lck_mtx_unlock(&nofp->nof_lock);
                if ((np->n_flag & NREVOKE) || (nofp->nof_flags & NFS_OPEN_FILE_LOST)) {
                        if (busied)
                                nfs_open_file_clear_busy(nofp);
                        continue;
                }
                /*
                 * If we just created the file, we already had it open in
                 * anticipation of getting a subsequent open call.  If the
                 * node has gone inactive without being open, we need to
                 * clean up (close) the open done in the create.
                 */
                if ((nofp->nof_flags & NFS_OPEN_FILE_CREATE) && nofp->nof_creator && !force) {
                        if (nofp->nof_flags & NFS_OPEN_FILE_REOPEN) {
                                lck_mtx_unlock(&np->n_openlock);
                                if (busied)
                                        nfs_open_file_clear_busy(nofp);
                                if (inuse)
                                        nfs_mount_state_in_use_end(nmp, 0);
                                if (!nfs4_reopen(nofp, NULL))
                                        goto restart;
                        }
                        nofp->nof_flags &= ~NFS_OPEN_FILE_CREATE;
                        lck_mtx_unlock(&np->n_openlock);
                        error = nfs_close(np, nofp, NFS_OPEN_SHARE_ACCESS_BOTH, NFS_OPEN_SHARE_DENY_NONE, ctx);
                        if (error) {
                                NP(np, "nfs_vnop_inactive: create close error: %d", error);
                                nofp->nof_flags |= NFS_OPEN_FILE_CREATE;
                        }
                        if (busied)
                                nfs_open_file_clear_busy(nofp);
                        if (inuse)
                                nfs_mount_state_in_use_end(nmp, error);
                        goto restart;
                }
                if (nofp->nof_flags & NFS_OPEN_FILE_NEEDCLOSE) {
                        /*
                         * If the file is marked as needing reopen, but this was the only
                         * open on the file, just drop the open.
                         */
                        nofp->nof_flags &= ~NFS_OPEN_FILE_NEEDCLOSE;
                        if ((nofp->nof_flags & NFS_OPEN_FILE_REOPEN) && (nofp->nof_opencnt == 1)) {
                                nofp->nof_flags &= ~NFS_OPEN_FILE_REOPEN;
                                nofp->nof_r--;
                                nofp->nof_opencnt--;
                                nofp->nof_access = 0;
                        } else if (!force) {
                                lck_mtx_unlock(&np->n_openlock);
                                if (nofp->nof_flags & NFS_OPEN_FILE_REOPEN) {
                                        if (busied)
                                                nfs_open_file_clear_busy(nofp);
                                        if (inuse)
                                                nfs_mount_state_in_use_end(nmp, 0);
                                        if (!nfs4_reopen(nofp, NULL))
                                                goto restart;
                                }
                                error = nfs_close(np, nofp, NFS_OPEN_SHARE_ACCESS_READ, NFS_OPEN_SHARE_DENY_NONE, ctx);
                                if (error) {
                                        NP(np, "nfs_vnop_inactive: need close error: %d", error);
                                        nofp->nof_flags |= NFS_OPEN_FILE_NEEDCLOSE;
                                }
                                if (busied)
                                        nfs_open_file_clear_busy(nofp);
                                if (inuse)
                                        nfs_mount_state_in_use_end(nmp, error);
                                goto restart;
                        }
                }
                if (nofp->nof_opencnt && !force)
                        NP(np, "nfs_vnop_inactive: file still open: %d", nofp->nof_opencnt);
                if (!force && (nofp->nof_access || nofp->nof_deny ||
                    nofp->nof_mmap_access || nofp->nof_mmap_deny ||
                    nofp->nof_r || nofp->nof_w || nofp->nof_rw ||
                    nofp->nof_r_dw || nofp->nof_w_dw || nofp->nof_rw_dw ||
                    nofp->nof_r_drw || nofp->nof_w_drw || nofp->nof_rw_drw ||
                    nofp->nof_d_r || nofp->nof_d_w || nofp->nof_d_rw ||
                    nofp->nof_d_r_dw || nofp->nof_d_w_dw || nofp->nof_d_rw_dw ||
                    nofp->nof_d_r_drw || nofp->nof_d_w_drw || nofp->nof_d_rw_drw)) {
                        NP(np, "nfs_vnop_inactive: non-zero access: %d %d %d %d # %u.%u %u.%u %u.%u dw %u.%u %u.%u %u.%u drw %u.%u %u.%u %u.%u",
                                nofp->nof_access, nofp->nof_deny,
                                nofp->nof_mmap_access, nofp->nof_mmap_deny,
                                nofp->nof_r, nofp->nof_d_r,
                                nofp->nof_w, nofp->nof_d_w,
                                nofp->nof_rw, nofp->nof_d_rw,
                                nofp->nof_r_dw, nofp->nof_d_r_dw,
                                nofp->nof_w_dw, nofp->nof_d_w_dw,
                                nofp->nof_rw_dw, nofp->nof_d_rw_dw,
                                nofp->nof_r_drw, nofp->nof_d_r_drw,
                                nofp->nof_w_drw, nofp->nof_d_w_drw,
                                nofp->nof_rw_drw, nofp->nof_d_rw_drw);
                }
                if (busied)
                        nfs_open_file_clear_busy(nofp);
        }
        lck_mtx_unlock(&np->n_openlock);

        if (inuse && nfs_mount_state_in_use_end(nmp, error))
                goto restart;

        nfs_node_lock_force(np);

        if (vnode_vtype(vp) != VDIR) {
                nsp = np->n_sillyrename; 
                np->n_sillyrename = NULL;
        } else {
                nsp = NULL;
        }

        FSDBG_TOP(264, vp, np, np->n_flag, nsp);

        if (!nsp) {
                /* no silly file to clean up... */
                /* clear all flags other than these */
                np->n_flag &= (NMODIFIED);
                nfs_node_unlock(np);
                FSDBG_BOT(264, vp, np, np->n_flag, 0);
                return (0);
        }
        nfs_node_unlock(np);

        /* Remove the silly file that was rename'd earlier */

        /* flush all the buffers */
        nfs_vinvalbuf2(vp, V_SAVE, vfs_context_thread(ctx), nsp->nsr_cred, 1);

        /* try to get the latest attributes */
        attrerr = nfs_getattr(np, &nvattr, ctx, NGA_UNCACHED);

        /* Check if we should remove it from the node hash. */
        /* Leave it if inuse or it has multiple hard links. */
        if (vnode_isinuse(vp, 0) || (!attrerr && (nvattr.nva_nlink > 1))) {
                unhash = 0;
        } else {
                unhash = 1;
                ubc_setsize(vp, 0);
        }

        /* mark this node and the directory busy while we do the remove */
        busyerror = nfs_node_set_busy2(nsp->nsr_dnp, np, vfs_context_thread(ctx));

        /* lock the node while we remove the silly file */
        lck_mtx_lock(nfs_node_hash_mutex);
        while (np->n_hflag & NHLOCKED) {
                np->n_hflag |= NHLOCKWANT;
                msleep(np, nfs_node_hash_mutex, PINOD, "nfs_inactive", NULL);
        }
        np->n_hflag |= NHLOCKED;
        lck_mtx_unlock(nfs_node_hash_mutex);

        /* purge the name cache to deter others from finding it */
        bzero(&cn, sizeof(cn));
        cn.cn_nameptr = nsp->nsr_name;
        cn.cn_namelen = nsp->nsr_namlen;
        nfs_name_cache_purge(nsp->nsr_dnp, np, &cn, ctx);

        FSDBG(264, np, np->n_size, np->n_vattr.nva_size, 0xf00d00f1);

        /* now remove the silly file */
        nfs_removeit(nsp);

        /* clear all flags other than these */
        nfs_node_lock_force(np);
        np->n_flag &= (NMODIFIED);
        nfs_node_unlock(np);

        if (!busyerror)
                nfs_node_clear_busy2(nsp->nsr_dnp, np);

        if (unhash && vnode_isinuse(vp, 0)) {
                /* vnode now inuse after silly remove? */
                unhash = 0;
                ubc_setsize(vp, np->n_size);
        }

        lck_mtx_lock(nfs_node_hash_mutex);
        if (unhash) {
                /*
                 * remove nfsnode from hash now so we can't accidentally find it
                 * again if another object gets created with the same filehandle
                 * before this vnode gets reclaimed
                 */
                if (np->n_hflag & NHHASHED) {
                        LIST_REMOVE(np, n_hash);
                        np->n_hflag &= ~NHHASHED;
                        FSDBG(266, 0, np, np->n_flag, 0xb1eb1e);
                }
                vnode_recycle(vp);
        }
        /* unlock the node */
        np->n_hflag &= ~NHLOCKED;
        if (np->n_hflag & NHLOCKWANT) {
                np->n_hflag &= ~NHLOCKWANT;
                wakeup(np);
        }
        lck_mtx_unlock(nfs_node_hash_mutex);

        /* cleanup sillyrename info */
        if (nsp->nsr_cred != NOCRED)
                kauth_cred_unref(&nsp->nsr_cred);
        vnode_rele(NFSTOV(nsp->nsr_dnp));
        FREE_ZONE(nsp, sizeof(*nsp), M_NFSREQ);

        FSDBG_BOT(264, vp, np, np->n_flag, 0);
        return (0);
}

/*
 * Reclaim an nfsnode so that it can be used for other purposes.
 */
int
nfs_vnop_reclaim(ap)
        struct vnop_reclaim_args /* {
                struct vnodeop_desc *a_desc;
                vnode_t a_vp;
                vfs_context_t a_context;
        } */ *ap;
{
        vnode_t vp = ap->a_vp;
        nfsnode_t np = VTONFS(vp);
        vfs_context_t ctx = ap->a_context;
        struct nfs_open_file *nofp, *nextnofp;
        struct nfs_file_lock *nflp, *nextnflp;
        struct nfs_lock_owner *nlop, *nextnlop;
        struct nfsmount *nmp = np->n_mount ? VFSTONFS(np->n_mount) : NFSTONMP(np);
        mount_t mp = vnode_mount(vp);
        int force;

        FSDBG_TOP(265, vp, np, np->n_flag, 0);
        force = (!mp || (mp->mnt_kern_flag & MNTK_FRCUNMOUNT));

        /* There shouldn't be any open or lock state at this point */
        lck_mtx_lock(&np->n_openlock);

        if (nmp && (nmp->nm_vers >= NFS_VER4)) {
                /* need to drop a delegation */
                if (np->n_dreturn.tqe_next != NFSNOLIST) {
                        /* remove this node from the delegation return list */
                        lck_mtx_lock(&nmp->nm_lock);
                        if (np->n_dreturn.tqe_next != NFSNOLIST) {
                                TAILQ_REMOVE(&nmp->nm_dreturnq, np, n_dreturn);
                                np->n_dreturn.tqe_next = NFSNOLIST;
                        }
                        lck_mtx_unlock(&nmp->nm_lock);
                }
                if (np->n_dlink.tqe_next != NFSNOLIST) {
                        /* remove this node from the delegation list */
                        lck_mtx_lock(&nmp->nm_lock);
                        if (np->n_dlink.tqe_next != NFSNOLIST) {
                                TAILQ_REMOVE(&nmp->nm_delegations, np, n_dlink);
                                np->n_dlink.tqe_next = NFSNOLIST;
                        }
                        lck_mtx_unlock(&nmp->nm_lock);
                }
                if ((np->n_openflags & N_DELEG_MASK) && !force) {
                        /* try to return the delegation */
                        np->n_openflags &= ~N_DELEG_MASK;
                        nfs4_delegreturn_rpc(nmp, np->n_fhp, np->n_fhsize, &np->n_dstateid,
                                R_RECOVER, vfs_context_thread(ctx), vfs_context_ucred(ctx));
                }
                if (np->n_attrdirfh) {
                        FREE(np->n_attrdirfh, M_TEMP);
                        np->n_attrdirfh = NULL;
                }
        }

        /* clean up file locks */
        TAILQ_FOREACH_SAFE(nflp, &np->n_locks, nfl_link, nextnflp) {
                if (!(nflp->nfl_flags & NFS_FILE_LOCK_DEAD) && !force) {
                        NP(np, "nfs_vnop_reclaim: lock 0x%llx 0x%llx 0x%x (bc %d)",
                                nflp->nfl_start, nflp->nfl_end, nflp->nfl_flags, nflp->nfl_blockcnt);
                }
                if (!(nflp->nfl_flags & (NFS_FILE_LOCK_BLOCKED|NFS_FILE_LOCK_DEAD))) {
                        /* try sending an unlock RPC if it wasn't delegated */
                        if (!(nflp->nfl_flags & NFS_FILE_LOCK_DELEGATED) && !force)
                                nmp->nm_funcs->nf_unlock_rpc(np, nflp->nfl_owner, F_WRLCK, nflp->nfl_start, nflp->nfl_end, R_RECOVER,
                                        NULL, nflp->nfl_owner->nlo_open_owner->noo_cred);
                        lck_mtx_lock(&nflp->nfl_owner->nlo_lock);
                        TAILQ_REMOVE(&nflp->nfl_owner->nlo_locks, nflp, nfl_lolink);
                        lck_mtx_unlock(&nflp->nfl_owner->nlo_lock);
                }
                TAILQ_REMOVE(&np->n_locks, nflp, nfl_link);
                nfs_file_lock_destroy(nflp);
        }
        /* clean up lock owners */
        TAILQ_FOREACH_SAFE(nlop, &np->n_lock_owners, nlo_link, nextnlop) {
                if (!TAILQ_EMPTY(&nlop->nlo_locks) && !force)
                        NP(np, "nfs_vnop_reclaim: lock owner with locks");
                TAILQ_REMOVE(&np->n_lock_owners, nlop, nlo_link);
                nfs_lock_owner_destroy(nlop);
        }
        /* clean up open state */
        if (np->n_openrefcnt && !force)
                NP(np, "nfs_vnop_reclaim: still open: %d", np->n_openrefcnt);
        TAILQ_FOREACH_SAFE(nofp, &np->n_opens, nof_link, nextnofp) {
                if (nofp->nof_flags & NFS_OPEN_FILE_BUSY)
                        NP(np, "nfs_vnop_reclaim: open file busy");
                if (!(np->n_flag & NREVOKE) && !(nofp->nof_flags & NFS_OPEN_FILE_LOST)) {
                        if (nofp->nof_opencnt && !force)
                                NP(np, "nfs_vnop_reclaim: file still open: %d", nofp->nof_opencnt);
                        if (!force && (nofp->nof_access || nofp->nof_deny ||
                            nofp->nof_mmap_access || nofp->nof_mmap_deny ||
                            nofp->nof_r || nofp->nof_w || nofp->nof_rw ||
                            nofp->nof_r_dw || nofp->nof_w_dw || nofp->nof_rw_dw ||
                            nofp->nof_r_drw || nofp->nof_w_drw || nofp->nof_rw_drw ||
                            nofp->nof_d_r || nofp->nof_d_w || nofp->nof_d_rw ||
                            nofp->nof_d_r_dw || nofp->nof_d_w_dw || nofp->nof_d_rw_dw ||
                            nofp->nof_d_r_drw || nofp->nof_d_w_drw || nofp->nof_d_rw_drw)) {
                                NP(np, "nfs_vnop_reclaim: non-zero access: %d %d %d %d # %u.%u %u.%u %u.%u dw %u.%u %u.%u %u.%u drw %u.%u %u.%u %u.%u",
                                        nofp->nof_access, nofp->nof_deny,
                                        nofp->nof_mmap_access, nofp->nof_mmap_deny,
                                        nofp->nof_r, nofp->nof_d_r,
                                        nofp->nof_w, nofp->nof_d_w,
                                        nofp->nof_rw, nofp->nof_d_rw,
                                        nofp->nof_r_dw, nofp->nof_d_r_dw,
                                        nofp->nof_w_dw, nofp->nof_d_w_dw,
                                        nofp->nof_rw_dw, nofp->nof_d_rw_dw,
                                        nofp->nof_r_drw, nofp->nof_d_r_drw,
                                        nofp->nof_w_drw, nofp->nof_d_w_drw,
                                        nofp->nof_rw_drw, nofp->nof_d_rw_drw);
                                /* try sending a close RPC if it wasn't delegated */
                                if (nofp->nof_r || nofp->nof_w || nofp->nof_rw ||
                                    nofp->nof_r_dw || nofp->nof_w_dw || nofp->nof_rw_dw ||
                                    nofp->nof_r_drw || nofp->nof_w_drw || nofp->nof_rw_drw)
                                        nfs4_close_rpc(np, nofp, NULL, nofp->nof_owner->noo_cred, R_RECOVER);
                        }
                }
                TAILQ_REMOVE(&np->n_opens, nofp, nof_link);
                nfs_open_file_destroy(nofp);
        }
        lck_mtx_unlock(&np->n_openlock);

        if (np->n_monlink.le_next != NFSNOLIST) {
                /* Wait for any in-progress getattr to complete, */
                /* then remove this node from the monitored node list. */
                lck_mtx_lock(&nmp->nm_lock);
                while (np->n_mflag & NMMONSCANINPROG) {
                        struct timespec ts = { 1, 0 };
                        np->n_mflag |= NMMONSCANWANT;
                        msleep(&np->n_mflag, &nmp->nm_lock, PZERO-1, "nfswaitmonscan", &ts);
                }
                if (np->n_monlink.le_next != NFSNOLIST) {
                        LIST_REMOVE(np, n_monlink);
                        np->n_monlink.le_next = NFSNOLIST;
                }
                lck_mtx_unlock(&nmp->nm_lock);
        }

        lck_mtx_lock(nfs_buf_mutex);
        if (!force && (!LIST_EMPTY(&np->n_dirtyblkhd) || !LIST_EMPTY(&np->n_cleanblkhd)))
                NP(np, "nfs_reclaim: dropping %s buffers", (!LIST_EMPTY(&np->n_dirtyblkhd) ? "dirty" : "clean"));
        lck_mtx_unlock(nfs_buf_mutex);
        nfs_vinvalbuf(vp, V_IGNORE_WRITEERR, ap->a_context, 0);

        lck_mtx_lock(nfs_node_hash_mutex);

        if ((vnode_vtype(vp) != VDIR) && np->n_sillyrename) {
                if (!force)
                        NP(np, "nfs_reclaim: leaving unlinked file %s", np->n_sillyrename->nsr_name);
                if (np->n_sillyrename->nsr_cred != NOCRED)
                        kauth_cred_unref(&np->n_sillyrename->nsr_cred);
                vnode_rele(NFSTOV(np->n_sillyrename->nsr_dnp));
                FREE_ZONE(np->n_sillyrename, sizeof(*np->n_sillyrename), M_NFSREQ);
        }

        vnode_removefsref(vp);

        if (np->n_hflag & NHHASHED) {
                LIST_REMOVE(np, n_hash);
                np->n_hflag &= ~NHHASHED;
                FSDBG(266, 0, np, np->n_flag, 0xb1eb1e);
        }
        lck_mtx_unlock(nfs_node_hash_mutex);

        /*
         * Free up any directory cookie structures and large file handle
         * structures that might be associated with this nfs node.
         */
        nfs_node_lock_force(np);
        if ((vnode_vtype(vp) == VDIR) && np->n_cookiecache)
                FREE_ZONE(np->n_cookiecache, sizeof(struct nfsdmap), M_NFSDIROFF);
        if (np->n_fhsize > NFS_SMALLFH)
                FREE_ZONE(np->n_fhp, np->n_fhsize, M_NFSBIGFH);
        if (np->n_vattr.nva_acl)
                kauth_acl_free(np->n_vattr.nva_acl);
        nfs_node_unlock(np);
        vnode_clearfsnode(vp);

        if (np->n_parent) {
                if (!vnode_get(np->n_parent)) {
                        vnode_rele(np->n_parent);
                        vnode_put(np->n_parent);
                }
                np->n_parent = NULL;
        }

        lck_mtx_destroy(&np->n_lock, nfs_node_lck_grp);
        lck_rw_destroy(&np->n_datalock, nfs_data_lck_grp);
        lck_mtx_destroy(&np->n_openlock, nfs_open_grp);

        FSDBG_BOT(265, vp, np, np->n_flag, 0xd1ed1e);
        FREE_ZONE(np, sizeof(struct nfsnode), M_NFSNODE);
        return (0);
}

/*
 * Acquire an NFS node lock
 */

int
nfs_node_lock_internal(nfsnode_t np, int force)
{
        FSDBG_TOP(268, np, force, 0, 0);
        lck_mtx_lock(&np->n_lock);
        if (!force && !(np->n_hflag && NHHASHED)) {
                FSDBG_BOT(268, np, 0xdead, 0, 0);
                lck_mtx_unlock(&np->n_lock);
                return (ENOENT);
        }
        FSDBG_BOT(268, np, force, 0, 0);
        return (0);
}

int
nfs_node_lock(nfsnode_t np)
{
        return nfs_node_lock_internal(np, 0);
}

void
nfs_node_lock_force(nfsnode_t np)
{
        nfs_node_lock_internal(np, 1);
}

/*
 * Release an NFS node lock
 */
void
nfs_node_unlock(nfsnode_t np)
{
        FSDBG(269, np, current_thread(), 0, 0);
        lck_mtx_unlock(&np->n_lock);
}

/*
 * Acquire 2 NFS node locks
 *   - locks taken in reverse address order
 *   - both or neither of the locks are taken
 *   - only one lock taken per node (dup nodes are skipped)
 */
int
nfs_node_lock2(nfsnode_t np1, nfsnode_t np2)
{
        nfsnode_t first, second;
        int error;

        first = (np1 > np2) ? np1 : np2;
        second = (np1 > np2) ? np2 : np1;
        if ((error = nfs_node_lock(first)))
                return (error);
        if (np1 == np2)
                return (error);
        if ((error = nfs_node_lock(second)))
                nfs_node_unlock(first);
        return (error);
}

void
nfs_node_unlock2(nfsnode_t np1, nfsnode_t np2)
{
        nfs_node_unlock(np1);
        if (np1 != np2)
                nfs_node_unlock(np2);
}

/*
 * Manage NFS node busy state.
 * (Similar to NFS node locks above)
 */
int
nfs_node_set_busy(nfsnode_t np, thread_t thd)
{
        struct timespec ts = { 2, 0 };
        int error;

        if ((error = nfs_node_lock(np)))
                return (error);
        while (ISSET(np->n_flag, NBUSY)) {
                SET(np->n_flag, NBUSYWANT);
                msleep(np, &np->n_lock, PZERO-1, "nfsbusywant", &ts);
                if ((error = nfs_sigintr(NFSTONMP(np), NULL, thd, 0)))
                        break;
        }
        if (!error)
                SET(np->n_flag, NBUSY);
        nfs_node_unlock(np);
        return (error);
}

void
nfs_node_clear_busy(nfsnode_t np)
{
        int wanted;

        nfs_node_lock_force(np);
        wanted = ISSET(np->n_flag, NBUSYWANT);
        CLR(np->n_flag, NBUSY|NBUSYWANT);
        nfs_node_unlock(np);
        if (wanted)
                wakeup(np);
}

int
nfs_node_set_busy2(nfsnode_t np1, nfsnode_t np2, thread_t thd)
{
        nfsnode_t first, second;
        int error;

        first = (np1 > np2) ? np1 : np2;
        second = (np1 > np2) ? np2 : np1;
        if ((error = nfs_node_set_busy(first, thd)))
                return (error);
        if (np1 == np2)
                return (error);
        if ((error = nfs_node_set_busy(second, thd)))
                nfs_node_clear_busy(first);
        return (error);
}

void
nfs_node_clear_busy2(nfsnode_t np1, nfsnode_t np2)
{
        nfs_node_clear_busy(np1);
        if (np1 != np2)
                nfs_node_clear_busy(np2);
}

/* helper function to sort four nodes in reverse address order (no dupes) */
static void
nfs_node_sort4(nfsnode_t np1, nfsnode_t np2, nfsnode_t np3, nfsnode_t np4, nfsnode_t *list, int *lcntp)
{
        nfsnode_t na[2], nb[2];
        int a, b, i, lcnt;

        /* sort pairs then merge */
        na[0] = (np1 > np2) ? np1 : np2;
        na[1] = (np1 > np2) ? np2 : np1;
        nb[0] = (np3 > np4) ? np3 : np4;
        nb[1] = (np3 > np4) ? np4 : np3;
        for (a = b = i = lcnt = 0; i < 4; i++) {
                if (a >= 2)
                        list[lcnt] = nb[b++];
                else if ((b >= 2) || (na[a] >= nb[b]))
                        list[lcnt] = na[a++];
                else
                        list[lcnt] = nb[b++];
                if ((lcnt <= 0) || (list[lcnt] != list[lcnt-1]))
                        lcnt++; /* omit dups */
        }
        if (list[lcnt-1] == NULL)
                lcnt--;
        *lcntp = lcnt;
}

int
nfs_node_set_busy4(nfsnode_t np1, nfsnode_t np2, nfsnode_t np3, nfsnode_t np4, thread_t thd)
{
        nfsnode_t list[4];
        int i, lcnt, error;

        nfs_node_sort4(np1, np2, np3, np4, list, &lcnt);

        /* Now we can lock using list[0 - lcnt-1] */
        for (i = 0; i < lcnt; ++i)
                if ((error = nfs_node_set_busy(list[i], thd))) {
                        /* Drop any locks we acquired. */
                        while (--i >= 0)
                                nfs_node_clear_busy(list[i]);
                        return (error);
                }
        return (0);
}

void
nfs_node_clear_busy4(nfsnode_t np1, nfsnode_t np2, nfsnode_t np3, nfsnode_t np4)
{
        nfsnode_t list[4];
        int lcnt;

        nfs_node_sort4(np1, np2, np3, np4, list, &lcnt);
        while (--lcnt >= 0)
                nfs_node_clear_busy(list[lcnt]);
}

/*
 * Acquire an NFS node data lock
 */
void
nfs_data_lock(nfsnode_t np, int locktype)
{
        nfs_data_lock_internal(np, locktype, 1);
}
void
nfs_data_lock_noupdate(nfsnode_t np, int locktype)
{
        nfs_data_lock_internal(np, locktype, 0);
}
void
nfs_data_lock_internal(nfsnode_t np, int locktype, int updatesize)
{
        FSDBG_TOP(270, np, locktype, np->n_datalockowner, 0);
        if (locktype == NFS_DATA_LOCK_SHARED) {
                if (updatesize && ISSET(np->n_flag, NUPDATESIZE))
                        nfs_data_update_size(np, 0);
                lck_rw_lock_shared(&np->n_datalock);
        } else {
                lck_rw_lock_exclusive(&np->n_datalock);
                np->n_datalockowner = current_thread();
                if (updatesize && ISSET(np->n_flag, NUPDATESIZE))
                        nfs_data_update_size(np, 1);
        }
        FSDBG_BOT(270, np, locktype, np->n_datalockowner, 0);
}

/*
 * Release an NFS node data lock
 */
void
nfs_data_unlock(nfsnode_t np)
{
        nfs_data_unlock_internal(np, 1);
}
void
nfs_data_unlock_noupdate(nfsnode_t np)
{
        nfs_data_unlock_internal(np, 0);
}
void
nfs_data_unlock_internal(nfsnode_t np, int updatesize)
{
        int mine = (np->n_datalockowner == current_thread());
        FSDBG_TOP(271, np, np->n_datalockowner, current_thread(), 0);
        if (updatesize && mine && ISSET(np->n_flag, NUPDATESIZE))
                nfs_data_update_size(np, 1);
        np->n_datalockowner = NULL;
        lck_rw_done(&np->n_datalock);
        if (updatesize && !mine && ISSET(np->n_flag, NUPDATESIZE))
                nfs_data_update_size(np, 0);
        FSDBG_BOT(271, np, np->n_datalockowner, current_thread(), 0);
}


/*
 * update an NFS node's size
 */
void
nfs_data_update_size(nfsnode_t np, int datalocked)
{
        int error;

        FSDBG_TOP(272, np, np->n_flag, np->n_size, np->n_newsize);
        if (!datalocked) {
                nfs_data_lock(np, NFS_DATA_LOCK_EXCLUSIVE);
                /* grabbing data lock will automatically update size */
                nfs_data_unlock(np);
                FSDBG_BOT(272, np, np->n_flag, np->n_size, np->n_newsize);
                return;
        }
        error = nfs_node_lock(np);
        if (error || !ISSET(np->n_flag, NUPDATESIZE)) {
                if (!error)
                        nfs_node_unlock(np);
                FSDBG_BOT(272, np, np->n_flag, np->n_size, np->n_newsize);
                return;
        }
        CLR(np->n_flag, NUPDATESIZE);
        np->n_size = np->n_newsize;
        /* make sure we invalidate buffers the next chance we get */
        SET(np->n_flag, NNEEDINVALIDATE);
        nfs_node_unlock(np);
        ubc_setsize(NFSTOV(np), (off_t)np->n_size); /* XXX error? */
        FSDBG_BOT(272, np, np->n_flag, np->n_size, np->n_newsize);
}

#define DODEBUG 1
int
nfs_mount_is_dirty(mount_t mp)
{
        u_long i;
        nfsnode_t np;
#ifdef DODEBUG  
        struct timeval now, then, diff;
        u_long ncnt = 0;
        microuptime(&now);
#endif
        lck_mtx_lock(nfs_node_hash_mutex);
        for (i = 0; i <= nfsnodehash; i++) {
                LIST_FOREACH(np, &nfsnodehashtbl[i], n_hash) {
#ifdef DODEBUG
                        ncnt++;
#endif                  
                        if (np->n_mount == mp && !LIST_EMPTY(&np->n_dirtyblkhd))
                                goto out;
                }
        }
out:
        lck_mtx_unlock(nfs_node_hash_mutex);
#ifdef DODEBUG
        microuptime(&then);
        timersub(&then, &now, &diff);
        
        printf("nfs_mount_is_dirty took %lld mics for %ld slots and %ld nodes return %d\n",
               (uint64_t)diff.tv_sec * 1000000LL + diff.tv_usec, i, ncnt, (i <= nfsnodehash));
#endif

        return (i <=  nfsnodehash);
}