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      1 /*	$NetBSD: nfs_vfsops.c,v 1.246 2024/05/13 00:11:22 msaitoh Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1989, 1993, 1995
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Rick Macklem at The University of Guelph.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  *
     34  *	@(#)nfs_vfsops.c	8.12 (Berkeley) 5/20/95
     35  */
     36 
     37 #include <sys/cdefs.h>
     38 __KERNEL_RCSID(0, "$NetBSD: nfs_vfsops.c,v 1.246 2024/05/13 00:11:22 msaitoh Exp $");
     39 
     40 #if defined(_KERNEL_OPT)
     41 #include "opt_nfs.h"
     42 #endif
     43 
     44 #include <sys/param.h>
     45 #include <sys/ioctl.h>
     46 #include <sys/signal.h>
     47 #include <sys/proc.h>
     48 #include <sys/namei.h>
     49 #include <sys/device.h>
     50 #include <sys/vnode.h>
     51 #include <sys/kernel.h>
     52 #include <sys/mount.h>
     53 #include <sys/buf.h>
     54 #include <sys/mbuf.h>
     55 #include <sys/dirent.h>
     56 #include <sys/socket.h>
     57 #include <sys/socketvar.h>
     58 #include <sys/sysctl.h>
     59 #include <sys/systm.h>
     60 #include <sys/timetc.h>
     61 #include <sys/kauth.h>
     62 #include <sys/module.h>
     63 
     64 #include <net/if.h>
     65 #include <net/route.h>
     66 #include <netinet/in.h>
     67 
     68 #include <nfs/rpcv2.h>
     69 #include <nfs/nfsproto.h>
     70 #include <nfs/nfsnode.h>
     71 #include <nfs/nfs.h>
     72 #include <nfs/nfsmount.h>
     73 #include <nfs/xdr_subs.h>
     74 #include <nfs/nfsm_subs.h>
     75 #include <nfs/nfsdiskless.h>
     76 #include <nfs/nfs_var.h>
     77 
     78 MODULE(MODULE_CLASS_VFS, nfs, NULL);
     79 
     80 extern struct nfsstats nfsstats;
     81 extern int nfs_ticks;
     82 
     83 /*
     84  * keep a count of the nfs mounts to generate fictitious drive names
     85  * for the per drive stats.
     86  */
     87 unsigned int nfs_mount_count = 0;
     88 
     89 int nfs_commitsize;
     90 
     91 /*
     92  * nfs vfs operations.
     93  */
     94 
     95 extern const struct vnodeopv_desc nfsv2_vnodeop_opv_desc;
     96 extern const struct vnodeopv_desc spec_nfsv2nodeop_opv_desc;
     97 extern const struct vnodeopv_desc fifo_nfsv2nodeop_opv_desc;
     98 
     99 const struct vnodeopv_desc * const nfs_vnodeopv_descs[] = {
    100 	&nfsv2_vnodeop_opv_desc,
    101 	&spec_nfsv2nodeop_opv_desc,
    102 	&fifo_nfsv2nodeop_opv_desc,
    103 	NULL,
    104 };
    105 
    106 struct vfsops nfs_vfsops = {
    107 	.vfs_name = MOUNT_NFS,
    108 	.vfs_min_mount_data = sizeof (struct nfs_args),
    109 	.vfs_mount = nfs_mount,
    110 	.vfs_start = nfs_start,
    111 	.vfs_unmount = nfs_unmount,
    112 	.vfs_root = nfs_root,
    113 	.vfs_quotactl = (void *)eopnotsupp,
    114 	.vfs_statvfs = nfs_statvfs,
    115 	.vfs_sync = nfs_sync,
    116 	.vfs_loadvnode = nfs_loadvnode,
    117 	.vfs_vget = nfs_vget,
    118 	.vfs_fhtovp = nfs_fhtovp,
    119 	.vfs_vptofh = nfs_vptofh,
    120 	.vfs_init = nfs_vfs_init,
    121 	.vfs_done = nfs_vfs_done,
    122 	.vfs_mountroot = nfs_mountroot,
    123 	.vfs_snapshot = (void *)eopnotsupp,
    124 	.vfs_extattrctl = vfs_stdextattrctl,
    125 	.vfs_suspendctl = genfs_suspendctl,
    126 	.vfs_renamelock_enter = genfs_renamelock_enter,
    127 	.vfs_renamelock_exit = genfs_renamelock_exit,
    128 	.vfs_fsync = (void *)eopnotsupp,
    129 	.vfs_opv_descs = nfs_vnodeopv_descs
    130 };
    131 
    132 extern u_int32_t nfs_procids[NFS_NPROCS];
    133 extern u_int32_t nfs_prog, nfs_vers;
    134 
    135 static int nfs_mount_diskless(struct nfs_dlmount *, const char *,
    136     struct mount **, struct vnode **, struct lwp *);
    137 
    138 static int
    139 nfs_modcmd(modcmd_t cmd, void *arg)
    140 {
    141 	int error;
    142 
    143 	switch (cmd) {
    144 	case MODULE_CMD_INIT:
    145 		error = vfs_attach(&nfs_vfsops);
    146 		return error;
    147 	case MODULE_CMD_FINI:
    148 		error = vfs_detach(&nfs_vfsops);
    149 		return error;
    150 	default:
    151 		return ENOTTY;
    152 	}
    153 }
    154 
    155 /*
    156  * nfs statvfs call
    157  */
    158 int
    159 nfs_statvfs(struct mount *mp, struct statvfs *sbp)
    160 {
    161 	struct lwp *l = curlwp;
    162 	struct vnode *vp;
    163 	struct nfs_statfs *sfp;
    164 	char *cp;
    165 	u_int32_t *tl;
    166 	int32_t t1, t2;
    167 	char *bpos, *dpos, *cp2;
    168 	struct nfsmount *nmp = VFSTONFS(mp);
    169 	int error = 0, retattr;
    170 #ifdef NFS_V2_ONLY
    171 	const int v3 = 0;
    172 #else
    173 	int v3 = (nmp->nm_flag & NFSMNT_NFSV3);
    174 #endif
    175 	struct mbuf *mreq, *mrep = NULL, *md, *mb;
    176 	kauth_cred_t cred;
    177 	u_quad_t tquad;
    178 	struct nfsnode *np;
    179 
    180 #ifndef nolint
    181 	sfp = (struct nfs_statfs *)0;
    182 #endif
    183 	vp = nmp->nm_vnode;
    184 	np = VTONFS(vp);
    185 	cred = kauth_cred_alloc();
    186 #ifndef NFS_V2_ONLY
    187 	if (v3 && (nmp->nm_iflag & NFSMNT_GOTFSINFO) == 0)
    188 		(void)nfs_fsinfo(nmp, vp, cred, l);
    189 #endif
    190 	nfsstats.rpccnt[NFSPROC_FSSTAT]++;
    191 	nfsm_reqhead(np, NFSPROC_FSSTAT, NFSX_FH(v3));
    192 	nfsm_fhtom(np, v3);
    193 	nfsm_request(np, NFSPROC_FSSTAT, l, cred);
    194 	if (v3)
    195 		nfsm_postop_attr(vp, retattr, 0);
    196 	if (error) {
    197 		if (mrep != NULL) {
    198 			if (mrep->m_next != NULL)
    199 				printf("nfs_vfsops: nfs_statvfs would lose buffers\n");
    200 			m_freem(mrep);
    201 		}
    202 		goto nfsmout;
    203 	}
    204 	nfsm_dissect(sfp, struct nfs_statfs *, NFSX_STATFS(v3));
    205 	sbp->f_flag = nmp->nm_flag;
    206 	sbp->f_iosize = uimin(nmp->nm_rsize, nmp->nm_wsize);
    207 	if (v3) {
    208 		sbp->f_frsize = sbp->f_bsize = NFS_FABLKSIZE;
    209 		tquad = fxdr_hyper(&sfp->sf_tbytes);
    210 		sbp->f_blocks = ((quad_t)tquad / (quad_t)NFS_FABLKSIZE);
    211 		tquad = fxdr_hyper(&sfp->sf_fbytes);
    212 		sbp->f_bfree = ((quad_t)tquad / (quad_t)NFS_FABLKSIZE);
    213 		tquad = fxdr_hyper(&sfp->sf_abytes);
    214 		tquad = ((quad_t)tquad / (quad_t)NFS_FABLKSIZE);
    215 		sbp->f_bresvd = sbp->f_bfree - tquad;
    216 		sbp->f_bavail = tquad;
    217 		/* Handle older NFS servers returning negative values */
    218 		if ((quad_t)sbp->f_bavail < 0)
    219 			sbp->f_bavail = 0;
    220 		tquad = fxdr_hyper(&sfp->sf_tfiles);
    221 		sbp->f_files = tquad;
    222 		tquad = fxdr_hyper(&sfp->sf_ffiles);
    223 		sbp->f_ffree = tquad;
    224 		sbp->f_favail = tquad;
    225 		sbp->f_fresvd = 0;
    226 	} else {
    227 		sbp->f_bsize = NFS_FABLKSIZE;
    228 		sbp->f_frsize = fxdr_unsigned(int32_t, sfp->sf_bsize);
    229 		sbp->f_blocks = fxdr_unsigned(int32_t, sfp->sf_blocks);
    230 		sbp->f_bfree = fxdr_unsigned(int32_t, sfp->sf_bfree);
    231 		sbp->f_bavail = fxdr_unsigned(int32_t, sfp->sf_bavail);
    232 		sbp->f_fresvd = 0;
    233 		sbp->f_files = 0;
    234 		sbp->f_ffree = 0;
    235 		sbp->f_favail = 0;
    236 		sbp->f_fresvd = 0;
    237 	}
    238 	copy_statvfs_info(sbp, mp);
    239 	nfsm_reqdone;
    240 	kauth_cred_free(cred);
    241 	return (error);
    242 }
    243 
    244 #ifndef NFS_V2_ONLY
    245 /*
    246  * nfs version 3 fsinfo rpc call
    247  */
    248 int
    249 nfs_fsinfo(struct nfsmount *nmp, struct vnode *vp, kauth_cred_t cred, struct lwp *l)
    250 {
    251 	struct nfsv3_fsinfo *fsp;
    252 	char *cp;
    253 	int32_t t1, t2;
    254 	u_int32_t *tl, pref, xmax;
    255 	char *bpos, *dpos, *cp2;
    256 	int error = 0, retattr;
    257 	struct mbuf *mreq, *mrep, *md, *mb;
    258 	u_int64_t maxfsize;
    259 	struct nfsnode *np = VTONFS(vp);
    260 
    261 	nfsstats.rpccnt[NFSPROC_FSINFO]++;
    262 	nfsm_reqhead(np, NFSPROC_FSINFO, NFSX_FH(1));
    263 	nfsm_fhtom(np, 1);
    264 	nfsm_request(np, NFSPROC_FSINFO, l, cred);
    265 	nfsm_postop_attr(vp, retattr, 0);
    266 	if (!error) {
    267 		nfsm_dissect(fsp, struct nfsv3_fsinfo *, NFSX_V3FSINFO);
    268 		pref = fxdr_unsigned(u_int32_t, fsp->fs_wtpref);
    269 		if ((nmp->nm_flag & NFSMNT_WSIZE) == 0 &&
    270 		    pref < nmp->nm_wsize && pref >= NFS_FABLKSIZE)
    271 			nmp->nm_wsize = (pref + NFS_FABLKSIZE - 1) &
    272 				~(NFS_FABLKSIZE - 1);
    273 		xmax = fxdr_unsigned(u_int32_t, fsp->fs_wtmax);
    274 		if (xmax < nmp->nm_wsize && xmax > 0) {
    275 			nmp->nm_wsize = xmax & ~(NFS_FABLKSIZE - 1);
    276 			if (nmp->nm_wsize == 0)
    277 				nmp->nm_wsize = xmax;
    278 		}
    279 		pref = fxdr_unsigned(u_int32_t, fsp->fs_rtpref);
    280 		if ((nmp->nm_flag & NFSMNT_RSIZE) == 0 &&
    281 		    pref < nmp->nm_rsize && pref >= NFS_FABLKSIZE)
    282 			nmp->nm_rsize = (pref + NFS_FABLKSIZE - 1) &
    283 				~(NFS_FABLKSIZE - 1);
    284 		xmax = fxdr_unsigned(u_int32_t, fsp->fs_rtmax);
    285 		if (xmax < nmp->nm_rsize && xmax > 0) {
    286 			nmp->nm_rsize = xmax & ~(NFS_FABLKSIZE - 1);
    287 			if (nmp->nm_rsize == 0)
    288 				nmp->nm_rsize = xmax;
    289 		}
    290 		pref = fxdr_unsigned(u_int32_t, fsp->fs_dtpref);
    291 		if (pref < nmp->nm_readdirsize && pref >= NFS_DIRFRAGSIZ)
    292 			nmp->nm_readdirsize = (pref + NFS_DIRFRAGSIZ - 1) &
    293 				~(NFS_DIRFRAGSIZ - 1);
    294 		if (xmax < nmp->nm_readdirsize && xmax > 0) {
    295 			nmp->nm_readdirsize = xmax & ~(NFS_DIRFRAGSIZ - 1);
    296 			if (nmp->nm_readdirsize == 0)
    297 				nmp->nm_readdirsize = xmax;
    298 		}
    299 		nmp->nm_maxfilesize = 0xffffffffffffffffull;
    300 		maxfsize = fxdr_hyper(&fsp->fs_maxfilesize);
    301 		if (maxfsize > 0 && maxfsize < nmp->nm_maxfilesize)
    302 			nmp->nm_maxfilesize = maxfsize;
    303 		nmp->nm_mountp->mnt_fs_bshift =
    304 		    ffs(MIN(nmp->nm_rsize, nmp->nm_wsize)) - 1;
    305 		nmp->nm_iflag |= NFSMNT_GOTFSINFO;
    306 	}
    307 	nfsm_reqdone;
    308 	return (error);
    309 }
    310 #endif
    311 
    312 /*
    313  * Mount a remote root fs via. NFS.  It goes like this:
    314  * - Call nfs_boot_init() to fill in the nfs_diskless struct
    315  * - build the rootfs mount point and call mountnfs() to do the rest.
    316  */
    317 int
    318 nfs_mountroot(void)
    319 {
    320 	struct timespec ts;
    321 	struct nfs_diskless *nd;
    322 	struct vattr attr;
    323 	struct mount *mp;
    324 	struct vnode *vp;
    325 	struct lwp *l;
    326 	time_t n;
    327 	int error;
    328 
    329 	l = curlwp; /* XXX */
    330 
    331 	if (device_class(root_device) != DV_IFNET)
    332 		return (ENODEV);
    333 
    334 	/*
    335 	 * XXX time must be non-zero when we init the interface or else
    336 	 * the arp code will wedge.  [Fixed now in if_ether.c]
    337 	 * However, the NFS attribute cache gives false "hits" when the
    338 	 * current time < nfs_attrtimeo(nmp, np) so keep this in for now.
    339 	 */
    340 	if (time_second < NFS_MAXATTRTIMO) {
    341 		ts.tv_sec = NFS_MAXATTRTIMO;
    342 		ts.tv_nsec = 0;
    343 		tc_setclock(&ts);
    344 	}
    345 
    346 	/*
    347 	 * Call nfs_boot_init() to fill in the nfs_diskless struct.
    348 	 * Side effect:  Finds and configures a network interface.
    349 	 */
    350 	nd = kmem_zalloc(sizeof(*nd), KM_SLEEP);
    351 	error = nfs_boot_init(nd, l);
    352 	if (error) {
    353 		kmem_free(nd, sizeof(*nd));
    354 		return (error);
    355 	}
    356 
    357 	/*
    358 	 * Create the root mount point.
    359 	 */
    360 	error = nfs_mount_diskless(&nd->nd_root, "/", &mp, &vp, l);
    361 	if (error)
    362 		goto out;
    363 	printf("root on %s\n", nd->nd_root.ndm_host);
    364 
    365 	/*
    366 	 * Link it into the mount list.
    367 	 */
    368 	mountlist_append(mp);
    369 	rootvp = vp;
    370 	mp->mnt_vnodecovered = NULLVP;
    371 	vfs_unbusy(mp);
    372 
    373 	/* Get root attributes (for the time). */
    374 	vn_lock(vp, LK_SHARED | LK_RETRY);
    375 	error = VOP_GETATTR(vp, &attr, l->l_cred);
    376 	VOP_UNLOCK(vp);
    377 	if (error)
    378 		panic("nfs_mountroot: getattr for root");
    379 	n = attr.va_atime.tv_sec;
    380 #ifdef	DEBUG
    381 	printf("root time: 0x%jx\n", (intmax_t)n);
    382 #endif
    383 	setrootfstime(n);
    384 
    385 out:
    386 	if (error)
    387 		nfs_boot_cleanup(nd, l);
    388 	kmem_free(nd, sizeof(*nd));
    389 	return (error);
    390 }
    391 
    392 /*
    393  * Internal version of mount system call for diskless setup.
    394  * Separate function because we used to call it twice.
    395  * (once for root and once for swap)
    396  */
    397 static int
    398 nfs_mount_diskless(struct nfs_dlmount *ndmntp, const char *mntname, struct mount **mpp, struct vnode **vpp, struct lwp *l)
    399 	/* mntname:	 mount point name */
    400 {
    401 	struct mount *mp;
    402 	struct mbuf *m;
    403 	int error;
    404 
    405 	vfs_rootmountalloc(MOUNT_NFS, mntname, &mp);
    406 
    407 	mp->mnt_op = &nfs_vfsops;
    408 
    409 	/*
    410 	 * Historical practice expects NFS root file systems to
    411 	 * be initially mounted r/w.
    412 	 */
    413 	mp->mnt_flag &= ~MNT_RDONLY;
    414 
    415 	/* Get mbuf for server sockaddr. */
    416 	m = m_get(M_WAIT, MT_SONAME);
    417 	if (m == NULL)
    418 		panic("nfs_mountroot: mget soname for %s", mntname);
    419 	MCLAIM(m, &nfs_mowner);
    420 	memcpy(mtod(m, void *), (void *)ndmntp->ndm_args.addr,
    421 	      (m->m_len = ndmntp->ndm_args.addr->sa_len));
    422 
    423 	error = mountnfs(&ndmntp->ndm_args, mp, m, mntname,
    424 			 ndmntp->ndm_args.hostname, vpp, l);
    425 	if (error) {
    426 		vfs_unbusy(mp);
    427 		vfs_rele(mp);
    428 		printf("nfs_mountroot: mount %s failed: %d\n",
    429 		       mntname, error);
    430 	} else
    431 		*mpp = mp;
    432 
    433 	return (error);
    434 }
    435 
    436 void
    437 nfs_decode_args(struct nfsmount *nmp, struct nfs_args *argp, struct lwp *l)
    438 {
    439 	int s;
    440 	int adjsock;
    441 	int maxio;
    442 
    443 	s = splsoftnet();
    444 
    445 	/*
    446 	 * Silently clear NFSMNT_NOCONN if it's a TCP mount, it makes
    447 	 * no sense in that context.
    448 	 */
    449 	if (argp->sotype == SOCK_STREAM)
    450 		argp->flags &= ~NFSMNT_NOCONN;
    451 
    452 	/*
    453 	 * Cookie translation is not needed for v2, silently ignore it.
    454 	 */
    455 	if ((argp->flags & (NFSMNT_XLATECOOKIE|NFSMNT_NFSV3)) ==
    456 	    NFSMNT_XLATECOOKIE)
    457 		argp->flags &= ~NFSMNT_XLATECOOKIE;
    458 
    459 	/* Re-bind if rsrvd port requested and wasn't on one */
    460 	adjsock = !(nmp->nm_flag & NFSMNT_RESVPORT)
    461 		  && (argp->flags & NFSMNT_RESVPORT);
    462 	/* Also re-bind if we're switching to/from a connected UDP socket */
    463 	adjsock |= ((nmp->nm_flag & NFSMNT_NOCONN) !=
    464 		    (argp->flags & NFSMNT_NOCONN));
    465 
    466 	/* Update flags. */
    467 	nmp->nm_flag = argp->flags;
    468 	splx(s);
    469 
    470 	if ((argp->flags & NFSMNT_TIMEO) && argp->timeo > 0) {
    471 		nmp->nm_timeo = (argp->timeo * NFS_HZ + 5) / 10;
    472 		if (nmp->nm_timeo < NFS_MINTIMEO)
    473 			nmp->nm_timeo = NFS_MINTIMEO;
    474 		else if (nmp->nm_timeo > NFS_MAXTIMEO)
    475 			nmp->nm_timeo = NFS_MAXTIMEO;
    476 	}
    477 
    478 	if ((argp->flags & NFSMNT_RETRANS) && argp->retrans > 1) {
    479 		nmp->nm_retry = argp->retrans;
    480 		if (nmp->nm_retry > NFS_MAXREXMIT)
    481 			nmp->nm_retry = NFS_MAXREXMIT;
    482 	}
    483 
    484 #ifndef NFS_V2_ONLY
    485 	if (argp->flags & NFSMNT_NFSV3) {
    486 		if (argp->sotype == SOCK_DGRAM)
    487 			maxio = NFS_MAXDGRAMDATA;
    488 		else
    489 			maxio = NFS_MAXDATA;
    490 	} else
    491 #endif
    492 		maxio = NFS_V2MAXDATA;
    493 
    494 	if ((argp->flags & NFSMNT_WSIZE) && argp->wsize > 0) {
    495 		int osize = nmp->nm_wsize;
    496 		nmp->nm_wsize = argp->wsize;
    497 		/* Round down to multiple of blocksize */
    498 		nmp->nm_wsize &= ~(NFS_FABLKSIZE - 1);
    499 		if (nmp->nm_wsize <= 0)
    500 			nmp->nm_wsize = NFS_FABLKSIZE;
    501 		adjsock |= (nmp->nm_wsize != osize);
    502 	}
    503 	if (nmp->nm_wsize > maxio)
    504 		nmp->nm_wsize = maxio;
    505 	if (nmp->nm_wsize > MAXBSIZE)
    506 		nmp->nm_wsize = MAXBSIZE;
    507 
    508 	if ((argp->flags & NFSMNT_RSIZE) && argp->rsize > 0) {
    509 		int osize = nmp->nm_rsize;
    510 		nmp->nm_rsize = argp->rsize;
    511 		/* Round down to multiple of blocksize */
    512 		nmp->nm_rsize &= ~(NFS_FABLKSIZE - 1);
    513 		if (nmp->nm_rsize <= 0)
    514 			nmp->nm_rsize = NFS_FABLKSIZE;
    515 		adjsock |= (nmp->nm_rsize != osize);
    516 	}
    517 	if (nmp->nm_rsize > maxio)
    518 		nmp->nm_rsize = maxio;
    519 	if (nmp->nm_rsize > MAXBSIZE)
    520 		nmp->nm_rsize = MAXBSIZE;
    521 
    522 	if ((argp->flags & NFSMNT_READDIRSIZE) && argp->readdirsize > 0) {
    523 		nmp->nm_readdirsize = argp->readdirsize;
    524 		/* Round down to multiple of minimum blocksize */
    525 		nmp->nm_readdirsize &= ~(NFS_DIRFRAGSIZ - 1);
    526 		if (nmp->nm_readdirsize < NFS_DIRFRAGSIZ)
    527 			nmp->nm_readdirsize = NFS_DIRFRAGSIZ;
    528 		/* Bigger than buffer size makes no sense */
    529 		if (nmp->nm_readdirsize > NFS_DIRBLKSIZ)
    530 			nmp->nm_readdirsize = NFS_DIRBLKSIZ;
    531 	} else if (argp->flags & NFSMNT_RSIZE)
    532 		nmp->nm_readdirsize = nmp->nm_rsize;
    533 
    534 	if (nmp->nm_readdirsize > maxio)
    535 		nmp->nm_readdirsize = maxio;
    536 
    537 	if ((argp->flags & NFSMNT_MAXGRPS) && argp->maxgrouplist >= 0 &&
    538 		argp->maxgrouplist <= NFS_MAXGRPS)
    539 		nmp->nm_numgrps = argp->maxgrouplist;
    540 	if ((argp->flags & NFSMNT_READAHEAD) && argp->readahead >= 0 &&
    541 		argp->readahead <= NFS_MAXRAHEAD)
    542 		nmp->nm_readahead = argp->readahead;
    543 	if ((argp->flags & NFSMNT_DEADTHRESH) && argp->deadthresh >= 1 &&
    544 		argp->deadthresh <= NFS_NEVERDEAD)
    545 		nmp->nm_deadthresh = argp->deadthresh;
    546 
    547 	adjsock |= ((nmp->nm_sotype != argp->sotype) ||
    548 		    (nmp->nm_soproto != argp->proto));
    549 	nmp->nm_sotype = argp->sotype;
    550 	nmp->nm_soproto = argp->proto;
    551 
    552 	if (nmp->nm_so && adjsock) {
    553 		nfs_safedisconnect(nmp);
    554 		if (nmp->nm_sotype == SOCK_DGRAM)
    555 			while (nfs_connect(nmp, (struct nfsreq *)0, l)) {
    556 				printf("nfs_args: retrying connect\n");
    557 				kpause("nfscn3", false, hz, NULL);
    558 			}
    559 	}
    560 }
    561 
    562 /*
    563  * VFS Operations.
    564  *
    565  * mount system call
    566  * It seems a bit dumb to copyinstr() the host and path here and then
    567  * memcpy() them in mountnfs(), but I wanted to detect errors before
    568  * doing the sockargs() call because sockargs() allocates an mbuf and
    569  * an error after that means that I have to release the mbuf.
    570  */
    571 /* ARGSUSED */
    572 int
    573 nfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
    574 {
    575 	struct lwp *l = curlwp;
    576 	int error;
    577 	struct nfs_args *args = data;
    578 	struct mbuf *nam;
    579 	struct nfsmount *nmp = VFSTONFS(mp);
    580 	struct sockaddr *sa;
    581 	struct vnode *vp;
    582 	char *pth, *hst;
    583 	size_t len;
    584 	u_char *nfh;
    585 
    586 	if (args == NULL)
    587 		return EINVAL;
    588 	if (*data_len < sizeof *args)
    589 		return EINVAL;
    590 
    591 	if (mp->mnt_flag & MNT_GETARGS) {
    592 
    593 		if (nmp == NULL)
    594 			return (EIO);
    595 		if (args->addr != NULL) {
    596 			sa = mtod(nmp->nm_nam, struct sockaddr *);
    597 			error = copyout(sa, args->addr, sa->sa_len);
    598 			if (error)
    599 				return (error);
    600 			args->addrlen = sa->sa_len;
    601 		} else
    602 			args->addrlen = 0;
    603 
    604 		args->version = NFS_ARGSVERSION;
    605 		args->sotype = nmp->nm_sotype;
    606 		args->proto = nmp->nm_soproto;
    607 		args->fh = NULL;
    608 		args->fhsize = 0;
    609 		args->flags = nmp->nm_flag;
    610 		args->wsize = nmp->nm_wsize;
    611 		args->rsize = nmp->nm_rsize;
    612 		args->readdirsize = nmp->nm_readdirsize;
    613 		args->timeo = nmp->nm_timeo;
    614 		args->retrans = nmp->nm_retry;
    615 		args->maxgrouplist = nmp->nm_numgrps;
    616 		args->readahead = nmp->nm_readahead;
    617 		args->leaseterm = 0; /* dummy */
    618 		args->deadthresh = nmp->nm_deadthresh;
    619 		args->hostname = NULL;
    620 		*data_len = sizeof *args;
    621 		return 0;
    622 	}
    623 
    624 	if (args->version != NFS_ARGSVERSION)
    625 		return (EPROGMISMATCH);
    626 	if (args->flags & (NFSMNT_NQNFS|NFSMNT_KERB))
    627 		return (EPROGUNAVAIL);
    628 #ifdef NFS_V2_ONLY
    629 	if (args->flags & NFSMNT_NFSV3)
    630 		return (EPROGMISMATCH);
    631 #endif
    632 	if (mp->mnt_flag & MNT_UPDATE) {
    633 		if (nmp == NULL)
    634 			return (EIO);
    635 		/*
    636 		 * When doing an update, we can't change from or to
    637 		 * v3, or change cookie translation
    638 		 */
    639 		args->flags = (args->flags & ~(NFSMNT_NFSV3|NFSMNT_XLATECOOKIE)) |
    640 		    (nmp->nm_flag & (NFSMNT_NFSV3|NFSMNT_XLATECOOKIE));
    641 		nfs_decode_args(nmp, args, l);
    642 		return (0);
    643 	}
    644 	if (args->fhsize < 0 || args->fhsize > NFSX_V3FHMAX)
    645 		return (EINVAL);
    646 	nfh = malloc(NFSX_V3FHMAX, M_TEMP, M_WAITOK);
    647 	error = copyin(args->fh, nfh, args->fhsize);
    648 	if (error)
    649 		goto free_nfh;
    650 	pth = malloc(MNAMELEN, M_TEMP, M_WAITOK);
    651 	error = copyinstr(path, pth, MNAMELEN - 1, &len);
    652 	if (error)
    653 		goto free_pth;
    654 	memset(&pth[len], 0, MNAMELEN - len);
    655 	hst = malloc(MNAMELEN, M_TEMP, M_WAITOK);
    656 	error = copyinstr(args->hostname, hst, MNAMELEN - 1, &len);
    657 	if (error)
    658 		goto free_hst;
    659 	memset(&hst[len], 0, MNAMELEN - len);
    660 	/* sockargs() call must be after above copyin() calls */
    661 	error = sockargs(&nam, args->addr, args->addrlen, UIO_USERSPACE,
    662 	    MT_SONAME);
    663 	if (error)
    664 		goto free_hst;
    665 	MCLAIM(nam, &nfs_mowner);
    666 	args->fh = nfh;
    667 	error = mountnfs(args, mp, nam, pth, hst, &vp, l);
    668 
    669 free_hst:
    670 	free(hst, M_TEMP);
    671 free_pth:
    672 	free(pth, M_TEMP);
    673 free_nfh:
    674 	free(nfh, M_TEMP);
    675 
    676 	return (error);
    677 }
    678 
    679 /*
    680  * Common code for mount and mountroot
    681  */
    682 int
    683 mountnfs(struct nfs_args *argp, struct mount *mp, struct mbuf *nam, const char *pth, const char *hst, struct vnode **vpp, struct lwp *l)
    684 {
    685 	struct nfsmount *nmp;
    686 	struct nfsnode *np;
    687 	struct vnode *vp;
    688 	int error;
    689 	struct vattr *attrs;
    690 	kauth_cred_t cr;
    691 	char iosname[IOSTATNAMELEN];
    692 
    693 	/*
    694 	 * If the number of nfs iothreads to use has never
    695 	 * been set, create a reasonable number of them.
    696 	 */
    697 
    698 	if (nfs_niothreads < 0) {
    699 		nfs_set_niothreads(NFS_DEFAULT_NIOTHREADS);
    700 	}
    701 
    702 	if (mp->mnt_flag & MNT_UPDATE) {
    703 		nmp = VFSTONFS(mp);
    704 		/* update paths, file handles, etc, here	XXX */
    705 		m_freem(nam);
    706 		return 0;
    707 	}
    708 	nmp = kmem_zalloc(sizeof(*nmp), KM_SLEEP);
    709 	TAILQ_INIT(&nmp->nm_uidlruhead);
    710 	TAILQ_INIT(&nmp->nm_bufq);
    711 	rw_init(&nmp->nm_writeverflock);
    712 	mutex_init(&nmp->nm_lock, MUTEX_DEFAULT, IPL_NONE);
    713 	cv_init(&nmp->nm_rcvcv, "nfsrcv");
    714 	cv_init(&nmp->nm_sndcv, "nfssnd");
    715 	cv_init(&nmp->nm_aiocv, "nfsaio");
    716 	cv_init(&nmp->nm_disconcv, "nfsdis");
    717 
    718 	mp->mnt_data = nmp;
    719 	mp->mnt_stat.f_namemax = NFS_MAXNAMLEN;
    720 	vfs_getnewfsid(mp);
    721 	nmp->nm_mountp = mp;
    722 
    723 #ifndef NFS_V2_ONLY
    724 	if ((argp->flags & NFSMNT_NFSV3) == 0)
    725 #endif
    726 	{
    727 		if (argp->fhsize != NFSX_V2FH) {
    728 			return EINVAL;
    729 		}
    730 	}
    731 
    732 	/*
    733 	 * V2 can only handle 32 bit filesizes. For v3, nfs_fsinfo
    734 	 * will overwrite this.
    735 	 */
    736 	nmp->nm_maxfilesize = 0xffffffffLL;
    737 
    738 	nmp->nm_timeo = NFS_TIMEO;
    739 	nmp->nm_retry = NFS_RETRANS;
    740 	nmp->nm_wsize = NFS_WSIZE;
    741 	nmp->nm_rsize = NFS_RSIZE;
    742 	nmp->nm_readdirsize = NFS_READDIRSIZE;
    743 	nmp->nm_numgrps = NFS_MAXGRPS;
    744 	nmp->nm_readahead = NFS_DEFRAHEAD;
    745 	nmp->nm_deadthresh = NFS_DEFDEADTHRESH;
    746 	error = set_statvfs_info(pth, UIO_SYSSPACE, hst, UIO_SYSSPACE,
    747 	    mp->mnt_op->vfs_name, mp, l);
    748 	if (error)
    749 		goto bad;
    750 	nmp->nm_nam = nam;
    751 
    752 	/* Set up the sockets and per-host congestion */
    753 	nmp->nm_sotype = argp->sotype;
    754 	nmp->nm_soproto = argp->proto;
    755 
    756 	nfs_decode_args(nmp, argp, l);
    757 
    758 	mp->mnt_fs_bshift = ffs(MIN(nmp->nm_rsize, nmp->nm_wsize)) - 1;
    759 	mp->mnt_dev_bshift = DEV_BSHIFT;
    760 
    761 	/*
    762 	 * For Connection based sockets (TCP,...) defer the connect until
    763 	 * the first request, in case the server is not responding.
    764 	 */
    765 	if (nmp->nm_sotype == SOCK_DGRAM &&
    766 		(error = nfs_connect(nmp, (struct nfsreq *)0, l)))
    767 		goto bad;
    768 
    769 	/*
    770 	 * This is silly, but it has to be set so that vinifod() works.
    771 	 * We do not want to do an nfs_statvfs() here since we can get
    772 	 * stuck on a dead server and we are holding a lock on the mount
    773 	 * point.
    774 	 */
    775 	mp->mnt_stat.f_iosize = NFS_MAXDGRAMDATA;
    776 	error = nfs_nget(mp, (nfsfh_t *)argp->fh, argp->fhsize, &np);
    777 	if (error)
    778 		goto bad;
    779 	vp = NFSTOV(np);
    780 	attrs = malloc(sizeof(struct vattr), M_TEMP, M_WAITOK);
    781 	VOP_GETATTR(vp, attrs, l->l_cred);
    782 	if ((nmp->nm_flag & NFSMNT_NFSV3) && (vp->v_type == VDIR)) {
    783 		cr = kauth_cred_alloc();
    784 		kauth_cred_setuid(cr, attrs->va_uid);
    785 		kauth_cred_seteuid(cr, attrs->va_uid);
    786 		kauth_cred_setsvuid(cr, attrs->va_uid);
    787 		kauth_cred_setgid(cr, attrs->va_gid);
    788 		kauth_cred_setegid(cr, attrs->va_gid);
    789 		kauth_cred_setsvgid(cr, attrs->va_gid);
    790 		nfs_cookieheuristic(vp, &nmp->nm_iflag, l, cr);
    791 		kauth_cred_free(cr);
    792 	}
    793 	free(attrs, M_TEMP);
    794 
    795 	/*
    796 	 * A reference count is needed on the nfsnode representing the
    797 	 * remote root.  If this object is not persistent, then backward
    798 	 * traversals of the mount point (i.e. "..") will not work if
    799 	 * the nfsnode gets flushed out of the cache. Ufs does not have
    800 	 * this problem, because one can identify root inodes by their
    801 	 * number == UFS_ROOTINO (2). So, just unlock, but no rele.
    802 	 */
    803 
    804 	nmp->nm_vnode = vp;
    805 	if (vp->v_type == VNON)
    806 		vp->v_type = VDIR;
    807 	vp->v_vflag |= VV_ROOT;
    808 	VOP_UNLOCK(vp);
    809 	*vpp = vp;
    810 
    811 	snprintf(iosname, sizeof(iosname), "nfs%u", nfs_mount_count++);
    812 	nmp->nm_stats = iostat_alloc(IOSTAT_NFS, nmp, iosname);
    813 
    814 	return (0);
    815 bad:
    816 	nfs_disconnect(nmp);
    817 	rw_destroy(&nmp->nm_writeverflock);
    818 	mutex_destroy(&nmp->nm_lock);
    819 	cv_destroy(&nmp->nm_rcvcv);
    820 	cv_destroy(&nmp->nm_sndcv);
    821 	cv_destroy(&nmp->nm_aiocv);
    822 	cv_destroy(&nmp->nm_disconcv);
    823 	kmem_free(nmp, sizeof(*nmp));
    824 	m_freem(nam);
    825 	return (error);
    826 }
    827 
    828 /*
    829  * unmount system call
    830  */
    831 int
    832 nfs_unmount(struct mount *mp, int mntflags)
    833 {
    834 	struct nfsmount *nmp = VFSTONFS(mp);
    835 	struct vnode *vp;
    836 	int error, flags = 0;
    837 
    838 	if (mntflags & MNT_FORCE) {
    839 		mutex_enter(&nmp->nm_lock);
    840 		flags |= FORCECLOSE;
    841 		nmp->nm_iflag |= NFSMNT_DISMNTFORCE;
    842 		mutex_exit(&nmp->nm_lock);
    843 
    844 	}
    845 
    846 	/*
    847 	 * Goes something like this..
    848 	 * - Check for activity on the root vnode (other than ourselves).
    849 	 * - Call vflush() to clear out vnodes for this file system,
    850 	 *   except for the root vnode.
    851 	 * - Decrement reference on the vnode representing remote root.
    852 	 * - Close the socket
    853 	 * - Free up the data structures
    854 	 */
    855 	/*
    856 	 * We need to decrement the ref. count on the nfsnode representing
    857 	 * the remote root.  See comment in mountnfs().
    858 	 */
    859 	vp = nmp->nm_vnode;
    860 	error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
    861 	if (error != 0)
    862 		goto err;
    863 
    864 	if ((mntflags & MNT_FORCE) == 0 && vrefcnt(vp) > 1) {
    865 		VOP_UNLOCK(vp);
    866 		error = EBUSY;
    867 		goto err;
    868 	}
    869 
    870 	error = vflush(mp, vp, flags);
    871 	if (error) {
    872 		VOP_UNLOCK(vp);
    873 		goto err;
    874 	}
    875 
    876 	/*
    877 	 * We are now committed to the unmount; mark the mount structure
    878 	 * as doomed so that any sleepers kicked awake by nfs_disconnect
    879 	 * will go away cleanly.
    880 	 */
    881 	nmp->nm_iflag |= NFSMNT_DISMNT;
    882 
    883 	/*
    884 	 * No new async I/O will be added, but await for pending
    885 	 * ones to drain.
    886 	 */
    887 	while (nfs_iodbusy(nmp))
    888 		kpause("nfsumnt", false, hz, NULL);
    889 
    890 	/*
    891 	 * Clean up the stats... note that we carefully avoid decrementing
    892 	 * nfs_mount_count here for good reason - we may not be unmounting
    893 	 * the last thing mounted.
    894 	 */
    895 	iostat_free(nmp->nm_stats);
    896 
    897 	/*
    898 	 * There is one reference count to get rid of here
    899 	 * (see comment in mountnfs()).
    900 	 */
    901 	VOP_UNLOCK(vp);
    902 	vgone(vp);
    903 	nfs_disconnect(nmp);
    904 	m_freem(nmp->nm_nam);
    905 
    906 	rw_destroy(&nmp->nm_writeverflock);
    907 	mutex_destroy(&nmp->nm_lock);
    908 	cv_destroy(&nmp->nm_rcvcv);
    909 	cv_destroy(&nmp->nm_sndcv);
    910 	cv_destroy(&nmp->nm_aiocv);
    911 	cv_destroy(&nmp->nm_disconcv);
    912 	kmem_free(nmp, sizeof(*nmp));
    913 	return (0);
    914 
    915 err:
    916 	if (mntflags & MNT_FORCE) {
    917 		mutex_enter(&nmp->nm_lock);
    918 		nmp->nm_iflag &= ~NFSMNT_DISMNTFORCE;
    919 		mutex_exit(&nmp->nm_lock);
    920 	}
    921 
    922 	return error;
    923 }
    924 
    925 /*
    926  * Return root of a filesystem
    927  */
    928 int
    929 nfs_root(struct mount *mp, int lktype, struct vnode **vpp)
    930 {
    931 	struct vnode *vp;
    932 	struct nfsmount *nmp;
    933 	int error;
    934 
    935 	nmp = VFSTONFS(mp);
    936 	vp = nmp->nm_vnode;
    937 	vref(vp);
    938 	error = vn_lock(vp, lktype | LK_RETRY);
    939 	if (error != 0) {
    940 		vrele(vp);
    941 		return error;
    942 	}
    943 	*vpp = vp;
    944 	return (0);
    945 }
    946 
    947 extern int syncprt;
    948 
    949 static bool
    950 nfs_sync_selector(void *cl, struct vnode *vp)
    951 {
    952 
    953 	KASSERT(mutex_owned(vp->v_interlock));
    954 
    955 	return !LIST_EMPTY(&vp->v_dirtyblkhd) ||
    956 	    (vp->v_iflag & VI_ONWORKLST) != 0;
    957 }
    958 
    959 /*
    960  * Flush out the buffer cache
    961  */
    962 /* ARGSUSED */
    963 int
    964 nfs_sync(struct mount *mp, int waitfor, kauth_cred_t cred)
    965 {
    966 	struct vnode *vp;
    967 	struct vnode_iterator *marker;
    968 	int error, allerror = 0;
    969 
    970 	/*
    971 	 * Force stale buffer cache information to be flushed.
    972 	 */
    973 	vfs_vnode_iterator_init(mp, &marker);
    974 	while ((vp = vfs_vnode_iterator_next(marker, nfs_sync_selector,
    975 	    NULL)))
    976 	{
    977 		error = vn_lock(vp, LK_EXCLUSIVE);
    978 		if (error) {
    979 			vrele(vp);
    980 			continue;
    981 		}
    982 		error = VOP_FSYNC(vp, cred,
    983 		    waitfor == MNT_WAIT ? FSYNC_WAIT : 0, 0, 0);
    984 		if (error)
    985 			allerror = error;
    986 		vput(vp);
    987 	}
    988 	vfs_vnode_iterator_destroy(marker);
    989 	return allerror;
    990 }
    991 
    992 /*
    993  * NFS flat namespace lookup.
    994  * Currently unsupported.
    995  */
    996 /* ARGSUSED */
    997 int
    998 nfs_vget(struct mount *mp, ino_t ino, int lktype, struct vnode **vpp)
    999 {
   1000 
   1001 	return (EOPNOTSUPP);
   1002 }
   1003 
   1004 /*
   1005  * Do that sysctl thang...
   1006  */
   1007 static int
   1008 sysctl_vfs_nfs_iothreads(SYSCTLFN_ARGS)
   1009 {
   1010 	struct sysctlnode node;
   1011 	int val;
   1012 	int error;
   1013 
   1014 	val = nfs_niothreads;
   1015 	node = *rnode;
   1016 	node.sysctl_data = &val;
   1017         error = sysctl_lookup(SYSCTLFN_CALL(&node));
   1018 	if (error || newp == NULL)
   1019 		return error;
   1020 
   1021 	return nfs_set_niothreads(val);
   1022 }
   1023 
   1024 SYSCTL_SETUP(nfs_sysctl_init, "nfs sysctl")
   1025 {
   1026 
   1027 	sysctl_createv(clog, 0, NULL, NULL,
   1028 		       CTLFLAG_PERMANENT,
   1029 		       CTLTYPE_NODE, "nfs",
   1030 		       SYSCTL_DESCR("NFS vfs options"),
   1031 		       NULL, 0, NULL, 0,
   1032 		       CTL_VFS, 2, CTL_EOL);
   1033 	/*
   1034 	 * XXX the "2" above could be dynamic, thereby eliminating one
   1035 	 * more instance of the "number to vfs" mapping problem, but
   1036 	 * "2" is the order as taken from sys/mount.h
   1037 	 */
   1038 
   1039 	sysctl_createv(clog, 0, NULL, NULL,
   1040 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1041 		       CTLTYPE_STRUCT, "nfsstats",
   1042 		       SYSCTL_DESCR("NFS operation statistics"),
   1043 		       NULL, 0, &nfsstats, sizeof(nfsstats),
   1044 		       CTL_VFS, 2, NFS_NFSSTATS, CTL_EOL);
   1045 	sysctl_createv(clog, 0, NULL, NULL,
   1046 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1047 		       CTLTYPE_INT, "iothreads",
   1048 		       SYSCTL_DESCR("Number of NFS client processes desired"),
   1049 		       sysctl_vfs_nfs_iothreads, 0, NULL, 0,
   1050 		       CTL_VFS, 2, NFS_IOTHREADS, CTL_EOL);
   1051 }
   1052 
   1053 /* ARGSUSED */
   1054 int
   1055 nfs_fhtovp(struct mount *mp, struct fid *fid, int lktype, struct vnode **vpp)
   1056 {
   1057 	size_t fidsize;
   1058 	size_t fhsize;
   1059 	struct nfsnode *np;
   1060 	int error;
   1061 	struct vattr va;
   1062 
   1063 	fidsize = fid->fid_len;
   1064 	if (fidsize < sizeof(*fid)) {
   1065 		return EINVAL;
   1066 	}
   1067 	fhsize = fidsize - sizeof(*fid);
   1068 	if ((fhsize % NFSX_UNSIGNED) != 0) {
   1069 		return EINVAL;
   1070 	}
   1071 	if ((VFSTONFS(mp)->nm_flag & NFSMNT_NFSV3) != 0) {
   1072 		if (fhsize > NFSX_V3FHMAX || fhsize == 0) {
   1073 			return EINVAL;
   1074 		}
   1075 	} else {
   1076 		if (fhsize != NFSX_V2FH) {
   1077 			return EINVAL;
   1078 		}
   1079 	}
   1080 	/* XXX lktype ignored */
   1081 	error = nfs_nget(mp, (void *)fid->fid_data, fhsize, &np);
   1082 	if (error) {
   1083 		return error;
   1084 	}
   1085 	*vpp = NFSTOV(np);
   1086 	error = VOP_GETATTR(*vpp, &va, kauth_cred_get());
   1087 	if (error != 0) {
   1088 		vput(*vpp);
   1089 		*vpp = NULLVP;
   1090 	}
   1091 	return error;
   1092 }
   1093 
   1094 /* ARGSUSED */
   1095 int
   1096 nfs_vptofh(struct vnode *vp, struct fid *buf, size_t *bufsize)
   1097 {
   1098 	struct nfsnode *np;
   1099 	struct fid *fid;
   1100 	size_t fidsize;
   1101 	int error = 0;
   1102 
   1103 	np = VTONFS(vp);
   1104 	fidsize = sizeof(*fid) + np->n_fhsize;
   1105 	if (*bufsize < fidsize) {
   1106 		error = E2BIG;
   1107 	}
   1108 	*bufsize = fidsize;
   1109 	if (error == 0) {
   1110 		struct fid fid_store;
   1111 
   1112 		fid = &fid_store;
   1113 		memset(fid, 0, sizeof(*fid));
   1114 		fid->fid_len = fidsize;
   1115 		memcpy(buf, fid, sizeof(*fid));
   1116 		memcpy(buf->fid_data, np->n_fhp, np->n_fhsize);
   1117 	}
   1118 	return error;
   1119 }
   1120 
   1121 /*
   1122  * Vfs start routine, a no-op.
   1123  */
   1124 /* ARGSUSED */
   1125 int
   1126 nfs_start(struct mount *mp, int flags)
   1127 {
   1128 
   1129 	return (0);
   1130 }
   1131 
   1132 /*
   1133  * Called once at VFS init to initialize client-specific data structures.
   1134  */
   1135 void
   1136 nfs_vfs_init(void)
   1137 {
   1138 	unsigned scale;
   1139 
   1140 	/* Initialize NFS server / client shared data. */
   1141 	nfs_init();
   1142 	nfs_node_init();
   1143 
   1144 	/* Initialize the kqueue structures */
   1145 	nfs_kqinit();
   1146 	/* Initialize the iod structures */
   1147 	nfs_iodinit();
   1148 
   1149 	scale = PAGE_SHIFT - 4;
   1150 	nfs_commitsize = uimin(uvmexp.npages, INT_MAX >> scale) << scale;
   1151 }
   1152 
   1153 void
   1154 nfs_vfs_done(void)
   1155 {
   1156 
   1157 	nfs_node_done();
   1158 	nfs_kqfini();
   1159 	nfs_iodfini();
   1160 	nfs_fini();
   1161 }
   1162