NFS performance fixes.

[dragonfly.git] / sys / vfs / nfs / nfs_vfsops.c

/*
 * 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. 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_vfsops.c        8.12 (Berkeley) 5/20/95
 * $FreeBSD: src/sys/nfs/nfs_vfsops.c,v 1.91.2.7 2003/01/27 20:04:08 dillon Exp $
 * $DragonFly: src/sys/vfs/nfs/nfs_vfsops.c,v 1.52 2008/07/14 17:45:49 dillon Exp $
 */

#include "opt_bootp.h"
#include "opt_nfsroot.h"

#include <sys/param.h>
#include <sys/sockio.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/systm.h>

#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_zone.h>

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

#include <sys/thread2.h>

#include "rpcv2.h"
#include "nfsproto.h"
#include "nfs.h"
#include "nfsmount.h"
#include "nfsnode.h"
#include "xdr_subs.h"
#include "nfsm_subs.h"
#include "nfsdiskless.h"
#include "nfsmountrpc.h"

extern int      nfs_mountroot(struct mount *mp);
extern void     bootpc_init(void);

extern int      nfs_ticks;
extern struct vop_ops nfsv2_vnode_vops;
extern struct vop_ops nfsv2_fifo_vops;
extern struct vop_ops nfsv2_spec_vops;

MALLOC_DEFINE(M_NFSREQ, "NFS req", "NFS request header");
MALLOC_DEFINE(M_NFSBIGFH, "NFSV3 bigfh", "NFS version 3 file handle");
MALLOC_DEFINE(M_NFSD, "NFS daemon", "Nfs server daemon structure");
MALLOC_DEFINE(M_NFSDIROFF, "NFSV3 diroff", "NFS directory offset data");
MALLOC_DEFINE(M_NFSRVDESC, "NFSV3 srvdesc", "NFS server socket descriptor");
MALLOC_DEFINE(M_NFSUID, "NFS uid", "Nfs uid mapping structure");
MALLOC_DEFINE(M_NFSHASH, "NFS hash", "NFS hash tables");

vm_zone_t nfsmount_zone;

struct nfsstats nfsstats;
SYSCTL_NODE(_vfs, OID_AUTO, nfs, CTLFLAG_RW, 0, "NFS filesystem");
SYSCTL_STRUCT(_vfs_nfs, NFS_NFSSTATS, nfsstats, CTLFLAG_RD,
        &nfsstats, nfsstats, "");
static int nfs_ip_paranoia = 1;
SYSCTL_INT(_vfs_nfs, OID_AUTO, nfs_ip_paranoia, CTLFLAG_RW,
        &nfs_ip_paranoia, 0, "");
#ifdef NFS_DEBUG
int nfs_debug;
SYSCTL_INT(_vfs_nfs, OID_AUTO, debug, CTLFLAG_RW, &nfs_debug, 0, "");
#endif

/*
 * Tunable to determine the Read/Write unit size.  Maximum value
 * is NFS_MAXDATA.  We also default to NFS_MAXDATA.
 */
static int nfs_io_size = NFS_MAXDATA;
SYSCTL_INT(_vfs_nfs, OID_AUTO, nfs_io_size, CTLFLAG_RW,
        &nfs_io_size, 0, "NFS optimal I/O unit size");

static void     nfs_decode_args (struct nfsmount *nmp,
                        struct nfs_args *argp);
static int      mountnfs (struct nfs_args *,struct mount *,
                        struct sockaddr *,char *,char *,struct vnode **);
static int      nfs_mount ( struct mount *mp, char *path, caddr_t data,
                        struct ucred *cred);
static int      nfs_unmount ( struct mount *mp, int mntflags);
static int      nfs_root ( struct mount *mp, struct vnode **vpp);
static int      nfs_statfs ( struct mount *mp, struct statfs *sbp,
                        struct ucred *cred);
static int      nfs_sync ( struct mount *mp, int waitfor);

/*
 * nfs vfs operations.
 */
static struct vfsops nfs_vfsops = {
        .vfs_mount =            nfs_mount,
        .vfs_unmount =          nfs_unmount,
        .vfs_root =             nfs_root,
        .vfs_statfs =           nfs_statfs,
        .vfs_sync =             nfs_sync,
        .vfs_init =             nfs_init,
        .vfs_uninit =           nfs_uninit
};
VFS_SET(nfs_vfsops, nfs, VFCF_NETWORK);

/*
 * This structure must be filled in by a primary bootstrap or bootstrap
 * server for a diskless/dataless machine. It is initialized below just
 * to ensure that it is allocated to initialized data (.data not .bss).
 */
struct nfs_diskless nfs_diskless = { { { 0 } } };
struct nfsv3_diskless nfsv3_diskless = { { { 0 } } };
int nfs_diskless_valid = 0;

SYSCTL_INT(_vfs_nfs, OID_AUTO, diskless_valid, CTLFLAG_RD, 
        &nfs_diskless_valid, 0, "");

SYSCTL_STRING(_vfs_nfs, OID_AUTO, diskless_rootpath, CTLFLAG_RD,
        nfsv3_diskless.root_hostnam, 0, "");

SYSCTL_OPAQUE(_vfs_nfs, OID_AUTO, diskless_rootaddr, CTLFLAG_RD,
        &nfsv3_diskless.root_saddr, sizeof nfsv3_diskless.root_saddr,
        "%Ssockaddr_in", "");

SYSCTL_STRING(_vfs_nfs, OID_AUTO, diskless_swappath, CTLFLAG_RD,
        nfsv3_diskless.swap_hostnam, 0, "");

SYSCTL_OPAQUE(_vfs_nfs, OID_AUTO, diskless_swapaddr, CTLFLAG_RD,
        &nfsv3_diskless.swap_saddr, sizeof nfsv3_diskless.swap_saddr, 
        "%Ssockaddr_in","");


void nfsargs_ntoh (struct nfs_args *);
static int nfs_mountdiskless (char *, char *, int,
                                  struct sockaddr_in *, struct nfs_args *,
                                  struct thread *, struct vnode **,
                                  struct mount **);
static void nfs_convert_diskless (void);
static void nfs_convert_oargs (struct nfs_args *args,
                                   struct onfs_args *oargs);

/*
 * Calculate the buffer I/O block size to use.  The maximum V2 block size
 * is typically 8K, the maximum datagram size is typically 16K, and the
 * maximum V3 block size is typically 32K.  The buffer cache tends to work
 * best with 16K blocks but we allow 32K for TCP connections.
 *
 * We force the block size to be at least a page for buffer cache efficiency.
 */
static int
nfs_iosize(int v3, int sotype)
{
        int iosize;
        int iomax;

        if (v3) {
                if (sotype == SOCK_STREAM)
                        iomax = NFS_MAXDATA;
                else
                        iomax = NFS_MAXDGRAMDATA;
        } else {
                iomax = NFS_V2MAXDATA;
        }
        if ((iosize = nfs_io_size) > iomax)
                iosize = iomax;
        if (iosize < PAGE_SIZE)
                iosize = PAGE_SIZE;

        /*
         * This is an aweful hack but until the buffer cache is rewritten
         * we need it.  The problem is that when you combine write() with
         * mmap() the vm_page->valid bits can become weird looking
         * (e.g. 0xfc).  This occurs because NFS uses piecemeal buffers
         * at the file EOF.  To solve the problem the BIO system needs to
         * be guarenteed that the NFS iosize for regular files will be a
         * multiple of PAGE_SIZE so it can invalidate the whole page
         * rather then just the piece of it owned by the buffer when
         * NFS does vinvalbuf() calls.
         */
        if (iosize & PAGE_MASK)
                iosize = (iosize & ~PAGE_MASK) + PAGE_SIZE;
        return iosize;
}

static void
nfs_convert_oargs(struct nfs_args *args, struct onfs_args *oargs)
{
        args->version = NFS_ARGSVERSION;
        args->addr = oargs->addr;
        args->addrlen = oargs->addrlen;
        args->sotype = oargs->sotype;
        args->proto = oargs->proto;
        args->fh = oargs->fh;
        args->fhsize = oargs->fhsize;
        args->flags = oargs->flags;
        args->wsize = oargs->wsize;
        args->rsize = oargs->rsize;
        args->readdirsize = oargs->readdirsize;
        args->timeo = oargs->timeo;
        args->retrans = oargs->retrans;
        args->maxgrouplist = oargs->maxgrouplist;
        args->readahead = oargs->readahead;
        args->deadthresh = oargs->deadthresh;
        args->hostname = oargs->hostname;
}

static void
nfs_convert_diskless(void)
{
        int i;

        bcopy(&nfs_diskless.myif, &nfsv3_diskless.myif,
                sizeof(struct ifaliasreq));
        bcopy(&nfs_diskless.mygateway, &nfsv3_diskless.mygateway,
                sizeof(struct sockaddr_in));
        nfs_convert_oargs(&nfsv3_diskless.swap_args,&nfs_diskless.swap_args);

        bcopy(nfs_diskless.swap_fh,nfsv3_diskless.swap_fh,NFSX_V2FH);
        nfsv3_diskless.swap_fhsize = NFSX_V2FH;
        for (i = NFSX_V2FH - 1; i >= 0; --i) {
                if (nfs_diskless.swap_fh[i])
                        break;
        }
        if (i < 0)
                nfsv3_diskless.swap_fhsize = 0;

        bcopy(&nfs_diskless.swap_saddr,&nfsv3_diskless.swap_saddr,
                sizeof(struct sockaddr_in));
        bcopy(nfs_diskless.swap_hostnam,nfsv3_diskless.swap_hostnam, MNAMELEN);
        nfsv3_diskless.swap_nblks = nfs_diskless.swap_nblks;
        bcopy(&nfs_diskless.swap_ucred, &nfsv3_diskless.swap_ucred,
                sizeof(struct ucred));
        nfs_convert_oargs(&nfsv3_diskless.root_args,&nfs_diskless.root_args);

        bcopy(nfs_diskless.root_fh,nfsv3_diskless.root_fh,NFSX_V2FH);
        nfsv3_diskless.root_fhsize = NFSX_V2FH;
        for (i = NFSX_V2FH - 1; i >= 0; --i) {
                if (nfs_diskless.root_fh[i])
                        break;
        }
        if (i < 0)
                nfsv3_diskless.root_fhsize = 0;

        bcopy(&nfs_diskless.root_saddr,&nfsv3_diskless.root_saddr,
                sizeof(struct sockaddr_in));
        bcopy(nfs_diskless.root_hostnam,nfsv3_diskless.root_hostnam, MNAMELEN);
        nfsv3_diskless.root_time = nfs_diskless.root_time;
        bcopy(nfs_diskless.my_hostnam,nfsv3_diskless.my_hostnam,
                MAXHOSTNAMELEN);
        nfs_diskless_valid = 3;
}

/*
 * nfs statfs call
 */
int
nfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
{
        struct vnode *vp;
        struct nfs_statfs *sfp;
        caddr_t cp;
        u_int32_t *tl;
        int32_t t1, t2;
        caddr_t bpos, dpos, cp2;
        struct nfsmount *nmp = VFSTONFS(mp);
        thread_t td = curthread;
        int error = 0, v3 = (nmp->nm_flag & NFSMNT_NFSV3), retattr;
        struct mbuf *mreq, *mrep, *md, *mb, *mb2;
        struct nfsnode *np;
        u_quad_t tquad;

#ifndef nolint
        sfp = (struct nfs_statfs *)0;
#endif
        error = nfs_nget(mp, (nfsfh_t *)nmp->nm_fh, nmp->nm_fhsize, &np);
        if (error)
                return (error);
        vp = NFSTOV(np);
        /* ignore the passed cred */
        cred = crget();
        cred->cr_ngroups = 1;
        if (v3 && (nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
                (void)nfs_fsinfo(nmp, vp, td);
        nfsstats.rpccnt[NFSPROC_FSSTAT]++;
        nfsm_reqhead(vp, NFSPROC_FSSTAT, NFSX_FH(v3));
        nfsm_fhtom(vp, v3);
        nfsm_request(vp, NFSPROC_FSSTAT, td, cred);
        if (v3)
                nfsm_postop_attr(vp, retattr, NFS_LATTR_NOSHRINK);
        if (error) {
                if (mrep != NULL)
                        m_freem(mrep);
                goto nfsmout;
        }
        nfsm_dissect(sfp, struct nfs_statfs *, NFSX_STATFS(v3));
        sbp->f_flags = nmp->nm_flag;
        sbp->f_iosize = nfs_iosize(v3, nmp->nm_sotype);

        if (v3) {
                sbp->f_bsize = NFS_FABLKSIZE;
                tquad = fxdr_hyper(&sfp->sf_tbytes);
                sbp->f_blocks = (long)(tquad / ((u_quad_t)NFS_FABLKSIZE));
                tquad = fxdr_hyper(&sfp->sf_fbytes);
                sbp->f_bfree = (long)(tquad / ((u_quad_t)NFS_FABLKSIZE));
                tquad = fxdr_hyper(&sfp->sf_abytes);
                sbp->f_bavail = (long)(tquad / ((u_quad_t)NFS_FABLKSIZE));
                sbp->f_files = (fxdr_unsigned(int32_t,
                    sfp->sf_tfiles.nfsuquad[1]) & 0x7fffffff);
                sbp->f_ffree = (fxdr_unsigned(int32_t,
                    sfp->sf_ffiles.nfsuquad[1]) & 0x7fffffff);
        } 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;
        }
        if (sbp != &mp->mnt_stat) {
                sbp->f_type = mp->mnt_vfc->vfc_typenum;
                bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
        }
        m_freem(mrep);
nfsmout:
        vput(vp);
        crfree(cred);
        return (error);
}

/*
 * nfs version 3 fsinfo rpc call
 */
int
nfs_fsinfo(struct nfsmount *nmp, struct vnode *vp, struct thread *td)
{
        struct nfsv3_fsinfo *fsp;
        caddr_t cp;
        int32_t t1, t2;
        u_int32_t *tl, pref, max;
        caddr_t bpos, dpos, cp2;
        int error = 0, retattr;
        struct mbuf *mreq, *mrep, *md, *mb, *mb2;
        u_int64_t maxfsize;

        nfsstats.rpccnt[NFSPROC_FSINFO]++;
        nfsm_reqhead(vp, NFSPROC_FSINFO, NFSX_FH(1));
        nfsm_fhtom(vp, 1);
        nfsm_request(vp, NFSPROC_FSINFO, td, nfs_vpcred(vp, ND_READ));
        nfsm_postop_attr(vp, retattr, NFS_LATTR_NOSHRINK);
        if (!error) {
                nfsm_dissect(fsp, struct nfsv3_fsinfo *, NFSX_V3FSINFO);
                pref = fxdr_unsigned(u_int32_t, fsp->fs_wtpref);
                if (pref < nmp->nm_wsize && pref >= NFS_FABLKSIZE)
                        nmp->nm_wsize = (pref + NFS_FABLKSIZE - 1) &
                                ~(NFS_FABLKSIZE - 1);
                max = fxdr_unsigned(u_int32_t, fsp->fs_wtmax);
                if (max < nmp->nm_wsize && max > 0) {
                        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 && pref >= NFS_FABLKSIZE)
                        nmp->nm_rsize = (pref + NFS_FABLKSIZE - 1) &
                                ~(NFS_FABLKSIZE - 1);
                max = fxdr_unsigned(u_int32_t, fsp->fs_rtmax);
                if (max < nmp->nm_rsize && max > 0) {
                        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 && pref >= NFS_DIRBLKSIZ)
                        nmp->nm_readdirsize = (pref + NFS_DIRBLKSIZ - 1) &
                                ~(NFS_DIRBLKSIZ - 1);
                if (max < nmp->nm_readdirsize && max > 0) {
                        nmp->nm_readdirsize = max & ~(NFS_DIRBLKSIZ - 1);
                        if (nmp->nm_readdirsize == 0)
                                nmp->nm_readdirsize = max;
                }
                maxfsize = fxdr_hyper(&fsp->fs_maxfilesize);
                if (maxfsize > 0 && maxfsize < nmp->nm_maxfilesize)
                        nmp->nm_maxfilesize = maxfsize;
                nmp->nm_state |= NFSSTA_GOTFSINFO;
        }
        m_freem(mrep);
nfsmout:
        return (error);
}

/*
 * Mount a remote root fs via. nfs. This depends on the info in the
 * nfs_diskless structure that has been filled in properly by some primary
 * bootstrap.
 * It goes something like this:
 * - do enough of "ifconfig" by calling ifioctl() so that the system
 *   can talk to the server
 * - If nfs_diskless.mygateway is filled in, use that address as
 *   a default gateway.
 * - build the rootfs mount point and call mountnfs() to do the rest.
 */
int
nfs_mountroot(struct mount *mp)
{
        struct mount  *swap_mp;
        struct nfsv3_diskless *nd = &nfsv3_diskless;
        struct socket *so;
        struct vnode *vp;
        struct thread *td = curthread;          /* XXX */
        int error, i;
        u_long l;
        char buf[128];

#if defined(BOOTP_NFSROOT) && defined(BOOTP)
        bootpc_init();          /* use bootp to get nfs_diskless filled in */
#endif

        /*
         * XXX time must be non-zero when we init the interface or else
         * the arp code will wedge...
         */
        while (mycpu->gd_time_seconds == 0)
                tsleep(mycpu, 0, "arpkludge", 10);

        /*
         * The boot code may have passed us a diskless structure.
         */
        if (nfs_diskless_valid == 1) 
                nfs_convert_diskless();

#define SINP(sockaddr)  ((struct sockaddr_in *)(sockaddr))
        kprintf("nfs_mountroot: interface %s ip %s",
                nd->myif.ifra_name, 
                inet_ntoa(SINP(&nd->myif.ifra_addr)->sin_addr));
        kprintf(" bcast %s", 
                inet_ntoa(SINP(&nd->myif.ifra_broadaddr)->sin_addr));
        kprintf(" mask %s\n", 
                inet_ntoa(SINP(&nd->myif.ifra_mask)->sin_addr));
#undef SINP

        /*
         * XXX splnet, so networks will receive...
         */
        crit_enter();

        /*
         * BOOTP does not necessarily have to be compiled into the kernel
         * for an NFS root to work.  If we inherited the network 
         * configuration for PXEBOOT then pxe_setup_nfsdiskless() has figured
         * out our interface for us and all we need to do is ifconfig the
         * interface.  We only do this if the interface has not already been
         * ifconfig'd by e.g. BOOTP.
         */
        error = socreate(nd->myif.ifra_addr.sa_family, &so, SOCK_DGRAM, 0, td);
        if (error) {
                panic("nfs_mountroot: socreate(%04x): %d",
                        nd->myif.ifra_addr.sa_family, error);
        }

        error = ifioctl(so, SIOCAIFADDR, (caddr_t)&nd->myif, proc0.p_ucred);
        if (error)
                panic("nfs_mountroot: SIOCAIFADDR: %d", error);

        soclose(so, FNONBLOCK);

        /*
         * If the gateway field is filled in, set it as the default route.
         */
        if (nd->mygateway.sin_len != 0) {
                struct sockaddr_in mask, sin;

                bzero((caddr_t)&mask, sizeof(mask));
                sin = mask;
                sin.sin_family = AF_INET;
                sin.sin_len = sizeof(sin);
                kprintf("nfs_mountroot: gateway %s\n",
                        inet_ntoa(nd->mygateway.sin_addr));
                error = rtrequest_global(RTM_ADD, (struct sockaddr *)&sin,
                                        (struct sockaddr *)&nd->mygateway,
                                        (struct sockaddr *)&mask,
                                        RTF_UP | RTF_GATEWAY);
                if (error)
                        kprintf("nfs_mountroot: unable to set gateway, error %d, continuing anyway\n", error);
        }

        /*
         * Create the rootfs mount point.
         */
        nd->root_args.fh = nd->root_fh;
        nd->root_args.fhsize = nd->root_fhsize;
        l = ntohl(nd->root_saddr.sin_addr.s_addr);
        ksnprintf(buf, sizeof(buf), "%ld.%ld.%ld.%ld:%s",
                (l >> 24) & 0xff, (l >> 16) & 0xff,
                (l >>  8) & 0xff, (l >>  0) & 0xff,nd->root_hostnam);
        kprintf("NFS ROOT: %s\n",buf);
        if ((error = nfs_mountdiskless(buf, "/", MNT_RDONLY,
            &nd->root_saddr, &nd->root_args, td, &vp, &mp)) != 0) {
                if (swap_mp) {
                        mp->mnt_vfc->vfc_refcount--;
                        kfree(swap_mp, M_MOUNT);
                }
                crit_exit();
                return (error);
        }

        swap_mp = NULL;
        if (nd->swap_nblks) {

                /* Convert to DEV_BSIZE instead of Kilobyte */
                nd->swap_nblks *= 2;

                /*
                 * Create a fake mount point just for the swap vnode so that the
                 * swap file can be on a different server from the rootfs.
                 */
                nd->swap_args.fh = nd->swap_fh;
                nd->swap_args.fhsize = nd->swap_fhsize;
                l = ntohl(nd->swap_saddr.sin_addr.s_addr);
                ksnprintf(buf, sizeof(buf), "%ld.%ld.%ld.%ld:%s",
                        (l >> 24) & 0xff, (l >> 16) & 0xff,
                        (l >>  8) & 0xff, (l >>  0) & 0xff,nd->swap_hostnam);
                kprintf("NFS SWAP: %s\n",buf);
                if ((error = nfs_mountdiskless(buf, "/swap", 0,
                    &nd->swap_saddr, &nd->swap_args, td, &vp, &swap_mp)) != 0) {
                        crit_exit();
                        return (error);
                }
                vfs_unbusy(swap_mp);

                VTONFS(vp)->n_size = VTONFS(vp)->n_vattr.va_size = 
                                nd->swap_nblks * DEV_BSIZE ;
                
                /*
                 * Since the swap file is not the root dir of a file system,
                 * hack it to a regular file.
                 */
                vp->v_flag = 0;
                vref(vp);
                nfs_setvtype(vp, VREG);
                swaponvp(td, vp, nd->swap_nblks);
        }

        mp->mnt_flag |= MNT_ROOTFS;
        vfs_unbusy(mp);

        /*
         * This is not really an nfs issue, but it is much easier to
         * set hostname here and then let the "/etc/rc.xxx" files
         * mount the right /var based upon its preset value.
         */
        bcopy(nd->my_hostnam, hostname, MAXHOSTNAMELEN);
        hostname[MAXHOSTNAMELEN - 1] = '\0';
        for (i = 0; i < MAXHOSTNAMELEN; i++)
                if (hostname[i] == '\0')
                        break;
        inittodr(ntohl(nd->root_time));
        crit_exit();
        return (0);
}

/*
 * Internal version of mount system call for diskless setup.
 */
static int
nfs_mountdiskless(char *path, char *which, int mountflag,
        struct sockaddr_in *sin, struct nfs_args *args, struct thread *td,
        struct vnode **vpp, struct mount **mpp)
{
        struct mount *mp;
        struct sockaddr *nam;
        int didalloc = 0;
        int error;

        mp = *mpp;

        if (mp == NULL) {
                if ((error = vfs_rootmountalloc("nfs", path, &mp)) != 0) {
                        kprintf("nfs_mountroot: NFS not configured");
                        return (error);
                }
                didalloc = 1;
        }
        mp->mnt_kern_flag = 0;
        mp->mnt_flag = mountflag;
        nam = dup_sockaddr((struct sockaddr *)sin);

#if defined(BOOTP) || defined(NFS_ROOT)
        if (args->fhsize == 0) {
                kprintf("NFS_ROOT: No FH passed from loader, attempting mount rpc...");
                args->fhsize = 0;
                error = md_mount(sin, which, args->fh, &args->fhsize, args, td);
                if (error) {
                        kprintf("failed.\n");
                        goto haderror;
                }
                kprintf("success!\n");
        }
#endif

        if ((error = mountnfs(args, mp, nam, which, path, vpp)) != 0) {
#if defined(BOOTP) || defined(NFS_ROOT)
haderror:
#endif
                kprintf("nfs_mountroot: mount %s on %s: %d", path, which, error);
                mp->mnt_vfc->vfc_refcount--;
                vfs_unbusy(mp);
                if (didalloc)
                        kfree(mp, M_MOUNT);
                FREE(nam, M_SONAME);
                return (error);
        }
        *mpp = mp;
        return (0);
}

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

        crit_enter();
        /*
         * Silently clear NFSMNT_NOCONN if it's a TCP mount, it makes
         * no sense in that context.
         */
        if (argp->sotype == SOCK_STREAM)
                nmp->nm_flag &= ~NFSMNT_NOCONN;

        /* Also clear RDIRPLUS if not NFSv3, it crashes some servers */
        if ((argp->flags & NFSMNT_NFSV3) == 0)
                nmp->nm_flag &= ~NFSMNT_RDIRPLUS;

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

        /* Update flags atomically.  Don't change the lock bits. */
        nmp->nm_flag = argp->flags | nmp->nm_flag;
        crit_exit();

        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 = argp->retrans;
                if (nmp->nm_retry > NFS_MAXREXMIT)
                        nmp->nm_retry = NFS_MAXREXMIT;
        }

        maxio = nfs_iosize(argp->flags & NFSMNT_NFSV3, argp->sotype);

        if ((argp->flags & NFSMNT_WSIZE) && argp->wsize > 0) {
                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;
        }
        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) {
                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;
        }
        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;
        }
        if (nmp->nm_readdirsize > maxio)
                nmp->nm_readdirsize = maxio;
        if (nmp->nm_readdirsize > nmp->nm_rsize)
                nmp->nm_readdirsize = nmp->nm_rsize;

        if ((argp->flags & NFSMNT_ACREGMIN) && argp->acregmin >= 0)
                nmp->nm_acregmin = argp->acregmin;
        else
                nmp->nm_acregmin = NFS_MINATTRTIMO;
        if ((argp->flags & NFSMNT_ACREGMAX) && argp->acregmax >= 0)
                nmp->nm_acregmax = argp->acregmax;
        else
                nmp->nm_acregmax = NFS_MAXATTRTIMO;
        if ((argp->flags & NFSMNT_ACDIRMIN) && argp->acdirmin >= 0)
                nmp->nm_acdirmin = argp->acdirmin;
        else
                nmp->nm_acdirmin = NFS_MINDIRATTRTIMO;
        if ((argp->flags & NFSMNT_ACDIRMAX) && argp->acdirmax >= 0)
                nmp->nm_acdirmax = argp->acdirmax;
        else
                nmp->nm_acdirmax = NFS_MAXDIRATTRTIMO;
        if (nmp->nm_acdirmin > nmp->nm_acdirmax)
                nmp->nm_acdirmin = nmp->nm_acdirmax;
        if (nmp->nm_acregmin > nmp->nm_acregmax)
                nmp->nm_acregmin = nmp->nm_acregmax;

        if ((argp->flags & NFSMNT_MAXGRPS) && argp->maxgrouplist >= 0) {
                if (argp->maxgrouplist <= NFS_MAXGRPS)
                        nmp->nm_numgrps = argp->maxgrouplist;
                else
                        nmp->nm_numgrps = NFS_MAXGRPS;
        }
        if ((argp->flags & NFSMNT_READAHEAD) && argp->readahead >= 0) {
                if (argp->readahead <= NFS_MAXRAHEAD)
                        nmp->nm_readahead = argp->readahead;
                else
                        nmp->nm_readahead = NFS_MAXRAHEAD;
        }
        if ((argp->flags & NFSMNT_DEADTHRESH) && argp->deadthresh >= 1) {
                if (argp->deadthresh <= NFS_NEVERDEAD)
                        nmp->nm_deadthresh = argp->deadthresh;
                else
                        nmp->nm_deadthresh = NFS_NEVERDEAD;
        }

        adjsock |= ((nmp->nm_sotype != argp->sotype) ||
                    (nmp->nm_soproto != argp->proto));
        nmp->nm_sotype = argp->sotype;
        nmp->nm_soproto = argp->proto;

        if (nmp->nm_so && adjsock) {
                nfs_safedisconnect(nmp);
                if (nmp->nm_sotype == SOCK_DGRAM)
                        while (nfs_connect(nmp, (struct nfsreq *)0)) {
                                kprintf("nfs_args: retrying connect\n");
                                (void) tsleep((caddr_t)&lbolt, 0, "nfscon", 0);
                        }
        }
}

/*
 * VFS Operations.
 *
 * mount system call
 * It seems a bit dumb to copyinstr() the host and path here and then
 * bcopy() them 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.
 */
/* ARGSUSED */
static int
nfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
{
        int error;
        struct nfs_args args;
        struct sockaddr *nam;
        struct vnode *vp;
        char pth[MNAMELEN], hst[MNAMELEN];
        size_t len;
        u_char nfh[NFSX_V3FHMAX];

        if (path == NULL) {
                nfs_mountroot(mp);
                return (0);
        }
        error = copyin(data, (caddr_t)&args, sizeof (struct nfs_args));
        if (error)
                return (error);
        if (args.version != NFS_ARGSVERSION) {
#ifdef COMPAT_PRELITE2
                /*
                 * If the argument version is unknown, then assume the
                 * caller is a pre-lite2 4.4BSD client and convert its
                 * arguments.
                 */
                struct onfs_args oargs;
                error = copyin(data, (caddr_t)&oargs, sizeof (struct onfs_args));
                if (error)
                        return (error);
                nfs_convert_oargs(&args,&oargs);
#else /* !COMPAT_PRELITE2 */
                return (EPROGMISMATCH);
#endif /* COMPAT_PRELITE2 */
        }
        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, or change cookie translation
                 */
                args.flags = (args.flags &
                    ~(NFSMNT_NFSV3/*|NFSMNT_XLATECOOKIE*/)) |
                    (nmp->nm_flag &
                        (NFSMNT_NFSV3/*|NFSMNT_XLATECOOKIE*/));
                nfs_decode_args(nmp, &args);
                return (0);
        }

        /*
         * Make the nfs_ip_paranoia sysctl serve as the default connection
         * or no-connection mode for those protocols that support 
         * no-connection mode (the flag will be cleared later for protocols
         * that do not support no-connection mode).  This will allow a client
         * to receive replies from a different IP then the request was
         * sent to.  Note: default value for nfs_ip_paranoia is 1 (paranoid),
         * not 0.
         */
        if (nfs_ip_paranoia == 0)
                args.flags |= NFSMNT_NOCONN;
        if (args.fhsize < 0 || args.fhsize > NFSX_V3FHMAX)
                return (EINVAL);
        error = copyin((caddr_t)args.fh, (caddr_t)nfh, args.fhsize);
        if (error)
                return (error);
        error = copyinstr(path, pth, MNAMELEN-1, &len);
        if (error)
                return (error);
        bzero(&pth[len], MNAMELEN - len);
        error = copyinstr(args.hostname, hst, MNAMELEN-1, &len);
        if (error)
                return (error);
        bzero(&hst[len], MNAMELEN - len);
        /* sockargs() call must be after above copyin() calls */
        error = getsockaddr(&nam, (caddr_t)args.addr, args.addrlen);
        if (error)
                return (error);
        args.fh = nfh;
        error = mountnfs(&args, mp, nam, pth, hst, &vp);
        return (error);
}

/*
 * Common code for mount and mountroot
 */
static int
mountnfs(struct nfs_args *argp, struct mount *mp, struct sockaddr *nam,
        char *pth, char *hst, struct vnode **vpp)
{
        struct nfsmount *nmp;
        struct nfsnode *np;
        int error;

        if (mp->mnt_flag & MNT_UPDATE) {
                nmp = VFSTONFS(mp);
                /* update paths, file handles, etc, here        XXX */
                FREE(nam, M_SONAME);
                return (0);
        } else {
                nmp = zalloc(nfsmount_zone);
                bzero((caddr_t)nmp, sizeof (struct nfsmount));
                TAILQ_INIT(&nmp->nm_uidlruhead);
                TAILQ_INIT(&nmp->nm_bioq);
                mp->mnt_data = (qaddr_t)nmp;
        }
        vfs_getnewfsid(mp);
        nmp->nm_mountp = mp;

        /*
         * V2 can only handle 32 bit filesizes.  A 4GB-1 limit may be too
         * high, depending on whether we end up with negative offsets in
         * the client or server somewhere.  2GB-1 may be safer.
         *
         * For V3, nfs_fsinfo will adjust this as necessary.  Assume maximum
         * that we can handle until we find out otherwise.
         * XXX Our "safe" limit on the client is what we can store in our
         * buffer cache using signed(!) block numbers.
         */
        if ((argp->flags & NFSMNT_NFSV3) == 0)
                nmp->nm_maxfilesize = 0xffffffffLL;
        else
                nmp->nm_maxfilesize = (u_int64_t)0x80000000 * DEV_BSIZE - 1;

        nmp->nm_timeo = NFS_TIMEO;
        nmp->nm_retry = NFS_RETRANS;
        nmp->nm_wsize = nfs_iosize(argp->flags & NFSMNT_NFSV3, argp->sotype);
        nmp->nm_rsize = nmp->nm_wsize;
        nmp->nm_readdirsize = NFS_READDIRSIZE;
        nmp->nm_numgrps = NFS_MAXGRPS;
        nmp->nm_readahead = NFS_DEFRAHEAD;
        nmp->nm_deadthresh = NFS_DEADTHRESH;
        nmp->nm_fhsize = argp->fhsize;
        bcopy((caddr_t)argp->fh, (caddr_t)nmp->nm_fh, argp->fhsize);
        bcopy(hst, mp->mnt_stat.f_mntfromname, MNAMELEN);
        nmp->nm_nam = nam;
        /* Set up the sockets and per-host congestion */
        nmp->nm_sotype = argp->sotype;
        nmp->nm_soproto = argp->proto;
        nmp->nm_cred = crhold(proc0.p_ucred);

        nfs_decode_args(nmp, argp);

        /*
         * 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, (struct nfsreq *)0)))
                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_iosize(nmp->nm_flag & NFSMNT_NFSV3, nmp->nm_sotype);

        /*
         * Install vop_ops for our vnops
         */
        vfs_add_vnodeops(mp, &nfsv2_vnode_vops, &mp->mnt_vn_norm_ops);
        vfs_add_vnodeops(mp, &nfsv2_spec_vops, &mp->mnt_vn_spec_ops);
        vfs_add_vnodeops(mp, &nfsv2_fifo_vops, &mp->mnt_vn_fifo_ops);

        /*
         * 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).
         */
        error = nfs_nget(mp, (nfsfh_t *)nmp->nm_fh, nmp->nm_fhsize, &np);
        if (error)
                goto bad;
        *vpp = NFSTOV(np);

        /*
         * Retrieval of mountpoint attributes is delayed until nfs_rot
         * or nfs_statfs are first called.  This will happen either when
         * we first traverse the mount point or if somebody does a df(1).
         *
         * NFSSTA_GOTFSINFO is used to flag if we have successfully
         * retrieved mountpoint attributes.  In the case of NFSv3 we
         * also flag static fsinfo.
         */
        if (*vpp != NULL)
                (*vpp)->v_type = VNON;

        /*
         * Lose the lock but keep the ref.
         */
        vn_unlock(*vpp);

        return (0);
bad:
        nfs_disconnect(nmp);
        nfs_free_mount(nmp);
        FREE(nam, M_SONAME);
        return (error);
}

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

        if (mntflags & MNT_FORCE)
                flags |= FORCECLOSE;
        nmp = VFSTONFS(mp);
        /*
         * Goes something like this..
         * - Call vflush() to clear out vnodes for this file system
         * - Close the socket
         * - Free up the data structures
         */
        /* In the forced case, cancel any outstanding requests. */
        if (flags & FORCECLOSE) {
                error = nfs_nmcancelreqs(nmp);
                if (error)
                        return (error);
        }
        /*
         * Must handshake with nfs_clientd() if it is active. XXX
         */
        nmp->nm_state |= NFSSTA_DISMINPROG;

        /* We hold 1 extra ref on the root vnode; see comment in mountnfs(). */
        error = vflush(mp, 1, flags);
        if (error) {
                nmp->nm_state &= ~NFSSTA_DISMINPROG;
                return (error);
        }

        /*
         * We are now committed to the unmount.
         * For NQNFS, let the server daemon free the nfsmount structure.
         */
        if (nmp->nm_flag & NFSMNT_KERB)
                nmp->nm_state |= NFSSTA_DISMNT;

        nfs_disconnect(nmp);
        FREE(nmp->nm_nam, M_SONAME);

        if ((nmp->nm_flag & NFSMNT_KERB) == 0)
                nfs_free_mount(nmp);
        return (0);
}

void
nfs_free_mount(struct nfsmount *nmp)
{
        if (nmp->nm_cred)  {
                crfree(nmp->nm_cred);
                nmp->nm_cred = NULL;
        }
        zfree(nfsmount_zone, nmp);
}

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

        nmp = VFSTONFS(mp);
        error = nfs_nget(mp, (nfsfh_t *)nmp->nm_fh, nmp->nm_fhsize, &np);
        if (error)
                return (error);
        vp = NFSTOV(np);

        /*
         * Get transfer parameters and root vnode attributes
         */
        if ((nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
            if (nmp->nm_flag & NFSMNT_NFSV3) {
                error = nfs_fsinfo(nmp, vp, curthread);
                mp->mnt_stat.f_iosize = nfs_iosize(1, nmp->nm_sotype);
            } else {
                if ((error = VOP_GETATTR(vp, &attrs)) == 0)
                        nmp->nm_state |= NFSSTA_GOTFSINFO;
                
            }
        } else {
            /*
             * The root vnode is usually cached by the namecache so do not
             * try to avoid going over the wire even if we have previous
             * information cached.  A stale NFS mount can loop
             * forever resolving the root vnode if we return no-error when
             * there is in fact an error.
             */
            np->n_attrstamp = 0;
            error = VOP_GETATTR(vp, &attrs);
        }
        if (vp->v_type == VNON)
            nfs_setvtype(vp, VDIR);
        vp->v_flag = VROOT;
        if (error)
                vput(vp);
        else
                *vpp = vp;
        return (error);
}

extern int syncprt;

struct scaninfo {
        int rescan;
        int waitfor;
        int allerror;
};

static int nfs_sync_scan1(struct mount *mp, struct vnode *vp, void *data);
static int nfs_sync_scan2(struct mount *mp, struct vnode *vp, void *data);

/*
 * Flush out the buffer cache
 */
/* ARGSUSED */
static int
nfs_sync(struct mount *mp, int waitfor)
{
        struct scaninfo scaninfo;
        int error;

        scaninfo.rescan = 1;
        scaninfo.waitfor = waitfor;
        scaninfo.allerror = 0;

        /*
         * Force stale buffer cache information to be flushed.
         */
        error = 0;
        while (error == 0 && scaninfo.rescan) {
                scaninfo.rescan = 0;
                error = vmntvnodescan(mp, VMSC_GETVP, nfs_sync_scan1,
                                        nfs_sync_scan2, &scaninfo);
        }
        return(error);
}

static int
nfs_sync_scan1(struct mount *mp, struct vnode *vp, void *data)
{
    struct scaninfo *info = data;

    if (vn_islocked(vp) || RB_EMPTY(&vp->v_rbdirty_tree))
        return(-1);
    if (info->waitfor == MNT_LAZY)
        return(-1);
    return(0);
}

static int
nfs_sync_scan2(struct mount *mp, struct vnode *vp, void *data)
{
    struct scaninfo *info = data;
    int error;

    error = VOP_FSYNC(vp, info->waitfor);
    if (error)
        info->allerror = error;
    return(0);
}