/*      $OpenBSD: nfs_vfsops.c,v 1.133 2025/06/12 20:37:59 deraadt Exp $        */
/*      $NetBSD: nfs_vfsops.c,v 1.46.4.1 1996/05/25 22:40:35 fvdl Exp $ */

/*
 * Copyright (c) 1989, 1993, 1995
 *      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.
 *
 *      @(#)nfs_vfsops.c        8.12 (Berkeley) 5/20/95
 */

#include <sys/param.h>
#include <sys/conf.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/lock.h>
#include <sys/kernel.h>
#include <sys/mount.h>
#include <sys/swap.h>
#include <sys/mbuf.h>
#include <sys/dirent.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/queue.h>

#include <netinet/in.h>

#include <nfs/nfsproto.h>
#include <nfs/nfsnode.h>
#include <nfs/nfs.h>
#include <nfs/nfsmount.h>
#include <nfs/xdr_subs.h>
#include <nfs/nfsdiskless.h>
#include <nfs/nfs_var.h>
#include <nfs/nfsm_subs.h>

extern struct nfsstats nfsstats;
extern int nfs_ticks;

int     nfs_sysctl(int *, u_int, void *, size_t *, void *, size_t,
            struct proc *);
int     nfs_checkexp(struct mount *, struct mbuf *, int *, struct ucred **);
struct  mount *nfs_mount_diskless(struct nfs_dlmount *, char *, int,
            struct vnode **, struct proc *p);
int     mountnfs(struct nfs_args *, struct mount *, struct mbuf *,
            const char *, char *, struct vnode **, struct proc *p);
int     nfs_quotactl(struct mount *, int, uid_t, caddr_t, struct proc *);
int     nfs_root(struct mount *, struct vnode **);
int     nfs_start(struct mount *, int, struct proc *);
int     nfs_statfs(struct mount *, struct statfs *, struct proc *);
int     nfs_sync(struct mount *, int, int, struct ucred *, struct proc *);
int     nfs_unmount(struct mount *, int, struct proc *);
void    nfs_reaper(void *);
int     nfs_vget(struct mount *, ino_t, struct vnode **);
int     nfs_vptofh(struct vnode *, struct fid *);
int     nfs_mountroot(void);
void    nfs_decode_args(struct nfsmount *, struct nfs_args *,
            struct nfs_args *);
int     nfs_fhtovp(struct mount *, struct fid *, struct vnode **);

/*
 * nfs vfs operations.
 */
const struct vfsops nfs_vfsops = {
        .vfs_mount      = nfs_mount,
        .vfs_start      = nfs_start,
        .vfs_unmount    = nfs_unmount,
        .vfs_root       = nfs_root,
        .vfs_quotactl   = nfs_quotactl,
        .vfs_statfs     = nfs_statfs,
        .vfs_sync       = nfs_sync,
        .vfs_vget       = nfs_vget,
        .vfs_fhtovp     = nfs_fhtovp,
        .vfs_vptofh     = nfs_vptofh,
        .vfs_init       = nfs_vfs_init,
#ifndef SMALL_KERNEL
        .vfs_sysctl     = nfs_sysctl,
#endif /* SMALL_KERNEL */
        .vfs_checkexp   = nfs_checkexp,
};

/*
 * nfs statfs call
 */
int
nfs_statfs(struct mount *mp, struct statfs *sbp, struct proc *p)
{
        struct vnode *vp;
        struct nfs_statfs *sfp = NULL;
        struct nfsm_info        info;
        struct nfsmount *nmp = VFSTONFS(mp);
        int error = 0, retattr;
        struct ucred *cred;
        u_quad_t tquad;

        info.nmi_v3 = (nmp->nm_flag & NFSMNT_NFSV3);
        info.nmi_errorp = &error;

        error = nfs_root(mp, &vp);
        if (error)
                return (error);
        cred = crget();
        cred->cr_ngroups = 0;
        if (info.nmi_v3 && (nmp->nm_flag & NFSMNT_GOTFSINFO) == 0)
                (void)nfs_fsinfo(nmp, vp, cred, p);
        nfsstats.rpccnt[NFSPROC_FSSTAT]++;
        info.nmi_mb = info.nmi_mreq = nfsm_reqhead(NFSX_FH(info.nmi_v3));
        nfsm_fhtom(&info, vp, info.nmi_v3);

        info.nmi_procp = p;
        info.nmi_cred = cred;
        error = nfs_request(vp, NFSPROC_FSSTAT, &info);
        if (info.nmi_v3) {
                if (nfsm_postop_attr(&info, &vp, &retattr) != 0)
                        goto nfsmout;
        }
        if (error) {
                m_freem(info.nmi_mrep);
                goto nfsmout;
        }

        sfp = (struct nfs_statfs *)
            nfsm_dissect(&info, NFSX_STATFS(info.nmi_v3));
        if (sfp == NULL)
                goto nfsmout;
        sbp->f_iosize = min(nmp->nm_rsize, nmp->nm_wsize);
        if (info.nmi_v3) {
                sbp->f_bsize = NFS_FABLKSIZE;
                tquad = fxdr_hyper(&sfp->sf_tbytes);
                sbp->f_blocks = tquad / (u_quad_t)NFS_FABLKSIZE;
                tquad = fxdr_hyper(&sfp->sf_fbytes);
                sbp->f_bfree = tquad / (u_quad_t)NFS_FABLKSIZE;
                tquad = fxdr_hyper(&sfp->sf_abytes);
                sbp->f_bavail = (quad_t)tquad / (quad_t)NFS_FABLKSIZE;

                tquad = fxdr_hyper(&sfp->sf_tfiles);
                sbp->f_files = tquad;
                tquad = fxdr_hyper(&sfp->sf_ffiles);
                sbp->f_ffree = tquad;
                sbp->f_favail = tquad;
        } else {
                sbp->f_bsize = fxdr_unsigned(int32_t, sfp->sf_bsize);
                sbp->f_blocks = fxdr_unsigned(int32_t, sfp->sf_blocks);
                sbp->f_bfree = fxdr_unsigned(int32_t, sfp->sf_bfree);
                sbp->f_bavail = fxdr_unsigned(int32_t, sfp->sf_bavail);
                sbp->f_files = 0;
                sbp->f_ffree = 0;
                sbp->f_favail = 0;
        }
        copy_statfs_info(sbp, mp);
        m_freem(info.nmi_mrep);
nfsmout: 
        vput(vp);
        crfree(cred);
        return (error);
}

/*
 * nfs version 3 fsinfo rpc call
 */
int
nfs_fsinfo(struct nfsmount *nmp, struct vnode *vp, struct ucred *cred,
    struct proc *p)
{
        struct nfsv3_fsinfo *fsp;
        struct nfsm_info        info;
        u_int32_t pref, max;
        int error = 0, retattr;

        nfsstats.rpccnt[NFSPROC_FSINFO]++;
        info.nmi_mb = info.nmi_mreq = nfsm_reqhead(NFSX_FH(1));
        nfsm_fhtom(&info, vp, 1);

        info.nmi_procp = p;
        info.nmi_cred = cred;
        info.nmi_errorp = &error;
        error = nfs_request(vp, NFSPROC_FSINFO, &info);

        if (nfsm_postop_attr(&info, &vp, &retattr) != 0)
                goto nfsmout;
        if (error) {
                m_freem(info.nmi_mrep);
                goto nfsmout;
        }

        fsp = (struct nfsv3_fsinfo *)nfsm_dissect(&info, NFSX_V3FSINFO);
        if (fsp == NULL)
                goto nfsmout;
        pref = fxdr_unsigned(u_int32_t, fsp->fs_wtpref);
        if (pref < nmp->nm_wsize)
                nmp->nm_wsize = (pref + NFS_FABLKSIZE - 1) &
                        ~(NFS_FABLKSIZE - 1);
        max = fxdr_unsigned(u_int32_t, fsp->fs_wtmax);
        if (max < nmp->nm_wsize) {
                nmp->nm_wsize = max & ~(NFS_FABLKSIZE - 1);
                if (nmp->nm_wsize == 0)
                        nmp->nm_wsize = max;
        }
        pref = fxdr_unsigned(u_int32_t, fsp->fs_rtpref);
        if (pref < nmp->nm_rsize)
                nmp->nm_rsize = (pref + NFS_FABLKSIZE - 1) &
                        ~(NFS_FABLKSIZE - 1);
        max = fxdr_unsigned(u_int32_t, fsp->fs_rtmax);
        if (max < nmp->nm_rsize) {
                nmp->nm_rsize = max & ~(NFS_FABLKSIZE - 1);
                if (nmp->nm_rsize == 0)
                        nmp->nm_rsize = max;
        }
        pref = fxdr_unsigned(u_int32_t, fsp->fs_dtpref);
        if (pref < nmp->nm_readdirsize)
                nmp->nm_readdirsize = (pref + NFS_DIRBLKSIZ - 1) &
                        ~(NFS_DIRBLKSIZ - 1);
        if (max < nmp->nm_readdirsize) {
                nmp->nm_readdirsize = max & ~(NFS_DIRBLKSIZ - 1);
                if (nmp->nm_readdirsize == 0)
                        nmp->nm_readdirsize = max;
        }
        nmp->nm_flag |= NFSMNT_GOTFSINFO;

        m_freem(info.nmi_mrep);
nfsmout: 
        return (error);
}

struct nfs_diskless nfs_diskless;

/*
 * Mount a remote root fs via. NFS.  It goes like this:
 * - Call nfs_boot_init() to fill in the nfs_diskless struct
 *   (using RARP, bootparam RPC, mountd RPC)
 * - hand craft the swap nfs vnode hanging off a fake mount point
 *      if swdevt[0] == NODEV
 * - build the rootfs mount point and call mountnfs() to do the rest.
 */
int
nfs_mountroot(void)
{
        struct vattr attr;
        struct mount *mp;
        struct vnode *vp;
        struct proc *procp;
        long n;
        int error;

        procp = curproc; /* XXX */

        /*
         * Call nfs_boot_init() to fill in the nfs_diskless struct.
         * Side effect:  Finds and configures a network interface.
         */
        nfs_boot_init(&nfs_diskless, procp);

        /*
         * Create the root mount point.
         */
        if (nfs_boot_getfh(&nfs_diskless.nd_boot, "root", &nfs_diskless.nd_root, -1))
                panic("nfs_mountroot: root");
        mp = nfs_mount_diskless(&nfs_diskless.nd_root, "/", 0, &vp, procp);
        printf("root on %s\n", nfs_diskless.nd_root.ndm_host);

        /*
         * Link it into the mount list.
         */
        TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
        rootvp = vp;
        vfs_unbusy(mp);

        /* Get root attributes (for the time). */
        error = VOP_GETATTR(rootvp, &attr, procp->p_ucred, procp);
        if (error) panic("nfs_mountroot: getattr for root");
        n = attr.va_atime.tv_sec;
#ifdef  DEBUG
        printf("root time: 0x%lx\n", n);
#endif
        inittodr(n);

#ifdef notyet
        /* Set up swap credentials. */
        proc0.p_ucred->cr_uid = ntohl(nfs_diskless.swap_ucred.cr_uid);
        proc0.p_ucred->cr_gid = ntohl(nfs_diskless.swap_ucred.cr_gid);
        if ((proc0.p_ucred->cr_ngroups = ntohs(nfs_diskless.swap_ucred.cr_ngroups)) >
                NGROUPS_MAX)
                proc0.p_ucred->cr_ngroups = NGROUPS_MAX;
        for (i = 0; i < proc0.p_ucred->cr_ngroups; i++)
            proc0.p_ucred->cr_groups[i] = ntohl(nfs_diskless.swap_ucred.cr_groups[i]);
#endif

        /*
         * "Mount" the swap device.
         *
         * On a "dataless" configuration (swap on disk) we will have:
         *      (swdevt[0] != NODEV) identifying the swap device.
         */
        if (swdevt[0] != NODEV) {
                if (bdevvp(swapdev, &swapdev_vp))
                        panic("nfs_mountroot: can't setup swap vp");
                printf("swap on device 0x%x\n", swdevt[0]);
                return (0);
        }

        /*
         * If swapping to an nfs node:  (swdevt[0] == NODEV)
         * Create a fake mount point just for the swap vnode so that the
         * swap file can be on a different server from the rootfs.
         *
         * Wait 5 retries, finally no swap is cool. -mickey
         */
        error = nfs_boot_getfh(&nfs_diskless.nd_boot, "swap", &nfs_diskless.nd_swap, 5);
        if (!error) {
                mp = nfs_mount_diskless(&nfs_diskless.nd_swap, "/swap", 0, &vp,
                    procp);
                vfs_unbusy(mp);

                /*
                 * Since the swap file is not the root dir of a file system,
                 * hack it to a regular file.
                 */
                vp->v_type = VREG;
                vp->v_flag = 0;

                /*
                 * Next line is a hack to make swapmount() work on NFS
                 * swap files.
                 */
                swdevt[0] = NETDEV;
                /* end hack */
                nfs_diskless.sw_vp = vp;

                /*
                 * Find out how large the swap file is.
                 */
                error = VOP_GETATTR(vp, &attr, procp->p_ucred, procp);
                if (error)
                        printf("nfs_mountroot: getattr for swap\n");
                n = (long) (attr.va_size >> DEV_BSHIFT);

                printf("swap on %s\n", nfs_diskless.nd_swap.ndm_host);
#ifdef  DEBUG
                printf("swap size: 0x%lx (blocks)\n", n);
#endif
                return (0);
        }

        printf("WARNING: no swap\n");
        swdevt[0] = NODEV;
        return (0);
}

/*
 * Internal version of mount system call for diskless setup.
 */
struct mount *
nfs_mount_diskless(struct nfs_dlmount *ndmntp, char *mntname, int mntflag,
    struct vnode **vpp, struct proc *p)
{
        struct mount *mp;
        struct mbuf *m;
        int error;

        if (vfs_rootmountalloc("nfs", mntname, &mp))
                panic("nfs_mount_diskless: vfs_rootmountalloc failed");
        mp->mnt_flag |= mntflag;

        /* Get mbuf for server sockaddr. */
        m = m_get(M_WAIT, MT_SONAME);
        bcopy(ndmntp->ndm_args.addr, mtod(m, caddr_t),
            (m->m_len = ndmntp->ndm_args.addr->sa_len));

        error = mountnfs(&ndmntp->ndm_args, mp, m, mntname,
            ndmntp->ndm_args.hostname, vpp, p);
        if (error)
                panic("nfs_mountroot: mount %s failed: %d", mntname, error);

        return (mp);
}

void
nfs_decode_args(struct nfsmount *nmp, struct nfs_args *argp,
    struct nfs_args *nargp)
{
        int adjsock = 0;
        int maxio;

#if 0
        /* Re-bind if rsrvd port requested and wasn't on one */
        adjsock = !(nmp->nm_flag & NFSMNT_RESVPORT)
                  && (argp->flags & NFSMNT_RESVPORT);
#endif
        /* Also re-bind if we're switching to/from a connected UDP socket */
        adjsock |= ((nmp->nm_flag & NFSMNT_NOCONN) !=
            (argp->flags & NFSMNT_NOCONN));

        nmp->nm_flag =
            (argp->flags & ~NFSMNT_INTERNAL) | (nmp->nm_flag & NFSMNT_INTERNAL);

        if ((argp->flags & NFSMNT_TIMEO) && argp->timeo > 0) {
                nmp->nm_timeo = (argp->timeo * NFS_HZ + 5) / 10;
                if (nmp->nm_timeo < NFS_MINTIMEO)
                        nmp->nm_timeo = NFS_MINTIMEO;
                else if (nmp->nm_timeo > NFS_MAXTIMEO)
                        nmp->nm_timeo = NFS_MAXTIMEO;
        }

        if ((argp->flags & NFSMNT_RETRANS) && argp->retrans > 1)
                nmp->nm_retry = MIN(argp->retrans, NFS_MAXREXMIT);
        if (!(nmp->nm_flag & NFSMNT_SOFT))
                nmp->nm_retry = NFS_MAXREXMIT + 1; /* past clip limit */

        if (argp->flags & NFSMNT_NFSV3) {
                if (argp->sotype == SOCK_DGRAM)
                        maxio = NFS_MAXDGRAMDATA;
                else
                        maxio = NFS_MAXDATA;
        } else
                maxio = NFS_V2MAXDATA;

        if ((argp->flags & NFSMNT_WSIZE) && argp->wsize > 0) {
                int osize = nmp->nm_wsize;
                nmp->nm_wsize = argp->wsize;
                /* Round down to multiple of blocksize */
                nmp->nm_wsize &= ~(NFS_FABLKSIZE - 1);
                if (nmp->nm_wsize <= 0)
                        nmp->nm_wsize = NFS_FABLKSIZE;
                adjsock |= (nmp->nm_wsize != osize);
        }
        if (nmp->nm_wsize > maxio)
                nmp->nm_wsize = maxio;
        if (nmp->nm_wsize > MAXBSIZE)
                nmp->nm_wsize = MAXBSIZE;

        if ((argp->flags & NFSMNT_RSIZE) && argp->rsize > 0) {
                int osize = nmp->nm_rsize;
                nmp->nm_rsize = argp->rsize;
                /* Round down to multiple of blocksize */
                nmp->nm_rsize &= ~(NFS_FABLKSIZE - 1);
                if (nmp->nm_rsize <= 0)
                        nmp->nm_rsize = NFS_FABLKSIZE;
                adjsock |= (nmp->nm_rsize != osize);
        }
        if (nmp->nm_rsize > maxio)
                nmp->nm_rsize = maxio;
        if (nmp->nm_rsize > MAXBSIZE)
                nmp->nm_rsize = MAXBSIZE;

        if ((argp->flags & NFSMNT_READDIRSIZE) && argp->readdirsize > 0) {
                nmp->nm_readdirsize = argp->readdirsize;
                /* Round down to multiple of blocksize */
                nmp->nm_readdirsize &= ~(NFS_DIRBLKSIZ - 1);
                if (nmp->nm_readdirsize < NFS_DIRBLKSIZ)
                        nmp->nm_readdirsize = NFS_DIRBLKSIZ;
        } else if (argp->flags & NFSMNT_RSIZE)
                nmp->nm_readdirsize = nmp->nm_rsize;

        if (nmp->nm_readdirsize > maxio)
                nmp->nm_readdirsize = maxio;

        if ((argp->flags & NFSMNT_MAXGRPS) && argp->maxgrouplist >= 0 &&
                argp->maxgrouplist <= NFS_MAXGRPS)
                nmp->nm_numgrps = argp->maxgrouplist;
        if ((argp->flags & NFSMNT_READAHEAD) && argp->readahead >= 0 &&
                argp->readahead <= NFS_MAXRAHEAD)
                nmp->nm_readahead = argp->readahead;
        if (argp->flags & NFSMNT_ACREGMIN && argp->acregmin >= 0) {
                if (argp->acregmin > 0xffff)
                        nmp->nm_acregmin = 0xffff;
                else
                        nmp->nm_acregmin = argp->acregmin;
        }
        if (argp->flags & NFSMNT_ACREGMAX && argp->acregmax >= 0) {
                if (argp->acregmax > 0xffff)
                        nmp->nm_acregmax = 0xffff;
                else
                        nmp->nm_acregmax = argp->acregmax;
        }
        if (nmp->nm_acregmin > nmp->nm_acregmax)
          nmp->nm_acregmin = nmp->nm_acregmax;

        if (argp->flags & NFSMNT_ACDIRMIN && argp->acdirmin >= 0) {
                if (argp->acdirmin > 0xffff)
                        nmp->nm_acdirmin = 0xffff;
                else
                        nmp->nm_acdirmin = argp->acdirmin;
        }
        if (argp->flags & NFSMNT_ACDIRMAX && argp->acdirmax >= 0) {
                if (argp->acdirmax > 0xffff)
                        nmp->nm_acdirmax = 0xffff;
                else
                        nmp->nm_acdirmax = argp->acdirmax;
        }
        if (nmp->nm_acdirmin > nmp->nm_acdirmax)
          nmp->nm_acdirmin = nmp->nm_acdirmax;

        if (nmp->nm_so && adjsock) {
                nfs_disconnect(nmp);
                if (nmp->nm_sotype == SOCK_DGRAM)
                        while (nfs_connect(nmp, NULL)) {
                                printf("nfs_args: retrying connect\n");
                                tsleep_nsec(&nowake, PSOCK, "nfscon",
                                    SEC_TO_NSEC(1));
                        }
        }

        /* Update nargp based on nmp */
        nargp->wsize = nmp->nm_wsize;
        nargp->rsize = nmp->nm_rsize;
        nargp->readdirsize = nmp->nm_readdirsize;
        nargp->timeo = nmp->nm_timeo;
        nargp->retrans = nmp->nm_retry;
        nargp->maxgrouplist = nmp->nm_numgrps;
        nargp->readahead = nmp->nm_readahead;
        nargp->acregmin = nmp->nm_acregmin;
        nargp->acregmax = nmp->nm_acregmax;
        nargp->acdirmin = nmp->nm_acdirmin;
        nargp->acdirmax = nmp->nm_acdirmax;
}

/*
 * VFS Operations.
 *
 * mount system call
 * It seems a bit dumb to copyinstr() the host here and then
 * bcopy() it in mountnfs(), but I wanted to detect errors before
 * doing the sockargs() call because sockargs() allocates an mbuf and
 * an error after that means that I have to release the mbuf.
 */
int
nfs_mount(struct mount *mp, const char *path, void *data,
    struct nameidata *ndp, struct proc *p)
{
        int error;
        struct nfs_args *args = data;
        struct mbuf *nam;
        struct vnode *vp;
        char hst[MNAMELEN];
        size_t len;
        u_char nfh[NFSX_V3FHMAX];

        if (args &&
            (args->flags & (NFSMNT_NFSV3|NFSMNT_RDIRPLUS)) == NFSMNT_RDIRPLUS)
                return (EINVAL);

        if (nfs_niothreads < 0) {
                nfs_niothreads = 4;
                nfs_getset_niothreads(1);
        }

        if (mp->mnt_flag & MNT_UPDATE) {
                struct nfsmount *nmp = VFSTONFS(mp);

                if (nmp == NULL)
                        return (EIO);
                /*
                 * When doing an update, we can't change from or to
                 * v3.
                 */
                if (args) {
                        args->flags = (args->flags & ~(NFSMNT_NFSV3)) |
                            (nmp->nm_flag & (NFSMNT_NFSV3));
                        nfs_decode_args(nmp, args, &mp->mnt_stat.mount_info.nfs_args);
                }
                return (0);
        }
        if (args->fhsize < 0 || args->fhsize > NFSX_V3FHMAX)
                return (EINVAL);
        error = copyin(args->fh, nfh, args->fhsize);
        if (error)
                return (error);
        error = copyinstr(args->hostname, hst, MNAMELEN-1, &len);
        if (error)
                return (error);
        memset(&hst[len], 0, MNAMELEN - len);
        /* sockargs() call must be after above copyin() calls */
        error = sockargs(&nam, args->addr, args->addrlen, MT_SONAME);
        if (error)
                return (error);
        args->fh = nfh;
        error = mountnfs(args, mp, nam, path, hst, &vp, p);
        return (error);
}

/*
 * Common code for mount and mountroot
 */
int
mountnfs(struct nfs_args *argp, struct mount *mp, struct mbuf *nam,
    const char *pth, char *hst, struct vnode **vpp, struct proc *p)
{
        struct nfsmount *nmp;
        struct nfsnode *np;
        struct vnode *vp;
        struct vattr attr;
        int error;

        if (mp->mnt_flag & MNT_UPDATE) {
                nmp = VFSTONFS(mp);
                /* update paths, file handles, etc, here        XXX */
                m_freem(nam);
                return (0);
        } else {
                nmp = malloc(sizeof(*nmp), M_NFSMNT,
                    M_WAITOK|M_ZERO);
                mp->mnt_data = nmp;
        }

        vfs_getnewfsid(mp);
        nmp->nm_mountp = mp;
        nmp->nm_timeo = NFS_TIMEO;
        nmp->nm_retry = NFS_RETRANS;
        nmp->nm_wsize = NFS_WSIZE;
        nmp->nm_rsize = NFS_RSIZE;
        nmp->nm_readdirsize = NFS_READDIRSIZE;
        nmp->nm_numgrps = NFS_MAXGRPS;
        nmp->nm_readahead = NFS_DEFRAHEAD;
        nmp->nm_acregmin = NFS_MINATTRTIMO;
        nmp->nm_acregmax = NFS_MAXATTRTIMO;
        nmp->nm_acdirmin = NFS_MINATTRTIMO;
        nmp->nm_acdirmax = NFS_MAXATTRTIMO;
        mp->mnt_stat.f_namemax = MAXNAMLEN;
        memset(mp->mnt_stat.f_mntonname, 0, MNAMELEN);
        strlcpy(mp->mnt_stat.f_mntonname, pth, MNAMELEN);
        memset(mp->mnt_stat.f_mntfromname, 0, MNAMELEN);
        strlcpy(mp->mnt_stat.f_mntfromname, hst, MNAMELEN);
        memset(mp->mnt_stat.f_mntfromspec, 0, MNAMELEN);
        strlcpy(mp->mnt_stat.f_mntfromspec, hst, MNAMELEN);
        bcopy(argp, &mp->mnt_stat.mount_info.nfs_args, sizeof(*argp));
        nmp->nm_nam = nam;
        nfs_decode_args(nmp, argp, &mp->mnt_stat.mount_info.nfs_args);

        nfs_ninit(nmp);
        TAILQ_INIT(&nmp->nm_reqsq);
        timeout_set_proc(&nmp->nm_rtimeout, nfs_timer, nmp);

        /* Set up the sockets and per-host congestion */
        nmp->nm_sotype = argp->sotype;
        nmp->nm_soproto = argp->proto;

        /*
         * For Connection based sockets (TCP,...) defer the connect until
         * the first request, in case the server is not responding.
         */
        if (nmp->nm_sotype == SOCK_DGRAM &&
            (error = nfs_connect(nmp, NULL)))
                goto bad;

        /*
         * This is silly, but it has to be set so that vinifod() works.
         * We do not want to do an nfs_statfs() here since we can get
         * stuck on a dead server and we are holding a lock on the mount
         * point.
         */
        mp->mnt_stat.f_iosize = NFS_MAXDGRAMDATA;
        error = nfs_nget(mp, (nfsfh_t *)argp->fh, argp->fhsize, &np);
        if (error)
                goto bad;
        vp = NFSTOV(np);
        error = VOP_GETATTR(vp, &attr, p->p_ucred, p);
        if (error) {
                vput(vp);
                goto bad;
        }

        /*
         * A reference count is needed on the nfsnode representing the
         * remote root.  If this object is not persistent, then backward
         * traversals of the mount point (i.e. "..") will not work if
         * the nfsnode gets flushed out of the cache. Ufs does not have
         * this problem, because one can identify root inodes by their
         * number == ROOTINO (2).  So, just unlock, but no rele.
         */
        nmp->nm_vnode = vp;
        if (vp->v_type == VNON)
                vp->v_type = VDIR;
        vp->v_flag = VROOT;
        VOP_UNLOCK(vp);
        *vpp = vp;

        return (0);
bad:
        nfs_disconnect(nmp);
        free(nmp, M_NFSMNT, sizeof(*nmp));
        m_freem(nam);
        return (error);
}

/* unmount system call */
int
nfs_unmount(struct mount *mp, int mntflags, struct proc *p)
{
        struct nfsmount *nmp;
        struct vnode *vp;
        int error, flags = 0;

        nmp = VFSTONFS(mp);
        error = nfs_root(mp, &vp);
        if (error)
                return (error);

        if ((mntflags & MNT_FORCE) == 0 && vp->v_usecount > 2) {
                vput(vp);
                return (EBUSY);
        }

        if (mntflags & MNT_FORCE)
                flags |= FORCECLOSE;

        error = vflush(mp, vp, flags);
        if (error) {
                vput(vp);
                return (error);
        }

        /*
         * There are two references count to get rid of here: one
         * from mountnfs() and one from nfs_root() above.
         */
        vrele(vp);
        vput(vp);
        vgone(vp);
        nfs_disconnect(nmp);
        m_freem(nmp->nm_nam);
        timeout_del(&nmp->nm_rtimeout);
        timeout_set_proc(&nmp->nm_rtimeout, nfs_reaper, nmp);
        timeout_add(&nmp->nm_rtimeout, 0);
        mp->mnt_data = NULL;
        return (0);
}

/*
 * Delay nfs mount point free until pending or sleeping timeouts have finished.
 */
void
nfs_reaper(void *arg)
{
        struct nfsmount *nmp = arg;

        free(nmp, M_NFSMNT, sizeof(*nmp));
}

/*
 * Return root of a filesystem
 */
int
nfs_root(struct mount *mp, struct vnode **vpp)
{
        struct vnode *vp;
        struct nfsmount *nmp;
        int error;

        nmp = VFSTONFS(mp);
        vp = nmp->nm_vnode;
        vref(vp);
        error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        if (error) {
                vrele(vp);
                return (error);
        }
        *vpp = vp;
        return (0);
}

/*
 * Flush out the buffer cache
 */
int
nfs_sync(struct mount *mp, int waitfor, int stall, struct ucred *cred, struct proc *p)
{
        struct vnode *vp;
        int allerror = 0;
        int empty, error, s;

        /*
         * Don't traverse the vnode list if we want to skip all of them.
         */
        if (waitfor == MNT_LAZY)
                return (allerror);

        /*
         * Force stale buffer cache information to be flushed.
         */
loop:
        TAILQ_FOREACH(vp, &mp->mnt_vnodelist, v_mntvnodes) {
                /*
                 * If the vnode that we are about to sync is no longer
                 * associated with this mount point, start over.
                 */
                if (vp->v_mount != mp)
                        goto loop;
                if (VOP_ISLOCKED(vp))
                        continue;
                s = splbio();
                empty = LIST_EMPTY(&vp->v_dirtyblkhd);
                splx(s);
                if (empty)
                        continue;
                if (vget(vp, LK_EXCLUSIVE))
                        goto loop;
                error = VOP_FSYNC(vp, cred, waitfor, p);
                if (error)
                        allerror = error;
                vput(vp);
        }

        return (allerror);
}

/*
 * NFS flat namespace lookup.
 * Currently unsupported.
 */
int
nfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp)
{

        return (EOPNOTSUPP);
}

#ifndef SMALL_KERNEL
/*
 * Do that sysctl thang...
 */
int
nfs_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
    size_t newlen, struct proc *p)
{
        int rv;

        /*
         * All names at this level are terminal.
         */
        if(namelen > 1)
                return ENOTDIR; /* overloaded */

        switch(name[0]) {
        case NFS_NFSSTATS:
                if(!oldp) {
                        *oldlenp = sizeof nfsstats;
                        return 0;
                }

                if(*oldlenp < sizeof nfsstats) {
                        *oldlenp = sizeof nfsstats;
                        return ENOMEM;
                }

                rv = copyout(&nfsstats, oldp, sizeof nfsstats);
                if(rv) return rv;

                if(newp && newlen != sizeof nfsstats)
                        return EINVAL;

                if(newp) {
                        return copyin(newp, &nfsstats, sizeof nfsstats);
                }
                return 0;

        case NFS_NIOTHREADS:
                nfs_getset_niothreads(0);

                rv = sysctl_int(oldp, oldlenp, newp, newlen, &nfs_niothreads);
                if (newp)
                        nfs_getset_niothreads(1);

                return rv;

        default:
                return EOPNOTSUPP;
        }
}
#endif /* SMALL_KERNEL */

/*
 * At this point, this should never happen
 */
int
nfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
{
        return (EINVAL);
}

/*
 * Vnode pointer to File handle, should never happen either
 */
int
nfs_vptofh(struct vnode *vp, struct fid *fhp)
{
        return (EINVAL);
}

/*
 * Vfs start routine, a no-op.
 */
int
nfs_start(struct mount *mp, int flags, struct proc *p)
{
        return (0);
}

/*
 * Do operations associated with quotas, not supported
 */
int
nfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg, struct proc *p)
{
        return (EOPNOTSUPP);
}

/*
 * check export permission, not supported
 */
/* ARGUSED */
int
nfs_checkexp(struct mount *mp, struct mbuf *nam, int *exflagsp,
    struct ucred **credanonp)
{
        return (EOPNOTSUPP);
}