1 /*	$NetBSD: filecore_vfsops.c,v 1.78 2015/03/28 19:24:05 maxv Exp $	*/
2 
3 /*-
4  * Copyright (c) 1994 The Regents of the University of California.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	filecore_vfsops.c	1.1	1998/6/26
32  */
33 
34 /*-
35  * Copyright (c) 1998 Andrew McMurry
36  *
37  * Redistribution and use in source and binary forms, with or without
38  * modification, are permitted provided that the following conditions
39  * are met:
40  * 1. Redistributions of source code must retain the above copyright
41  *    notice, this list of conditions and the following disclaimer.
42  * 2. Redistributions in binary form must reproduce the above copyright
43  *    notice, this list of conditions and the following disclaimer in the
44  *    documentation and/or other materials provided with the distribution.
45  * 3. All advertising materials mentioning features or use of this software
46  *    must display the following acknowledgement:
47  *	This product includes software developed by the University of
48  *	California, Berkeley and its contributors.
49  * 4. Neither the name of the University nor the names of its contributors
50  *    may be used to endorse or promote products derived from this software
51  *    without specific prior written permission.
52  *
53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
63  * SUCH DAMAGE.
64  *
65  *	filecore_vfsops.c	1.1	1998/6/26
66  */
67 
68 #include <sys/cdefs.h>
69 __KERNEL_RCSID(0, "$NetBSD: filecore_vfsops.c,v 1.78 2015/03/28 19:24:05 maxv Exp $");
70 
71 #if defined(_KERNEL_OPT)
72 #include "opt_compat_netbsd.h"
73 #endif
74 
75 #include <sys/param.h>
76 #include <sys/systm.h>
77 #include <sys/namei.h>
78 #include <sys/proc.h>
79 #include <sys/vnode.h>
80 #include <miscfs/genfs/genfs.h>
81 #include <miscfs/specfs/specdev.h>
82 #include <sys/mount.h>
83 #include <sys/buf.h>
84 #include <sys/file.h>
85 #include <sys/device.h>
86 #include <sys/errno.h>
87 #include <sys/pool.h>
88 #include <sys/conf.h>
89 #include <sys/sysctl.h>
90 #include <sys/kauth.h>
91 #include <sys/module.h>
92 
93 #include <fs/filecorefs/filecore.h>
94 #include <fs/filecorefs/filecore_extern.h>
95 #include <fs/filecorefs/filecore_node.h>
96 #include <fs/filecorefs/filecore_mount.h>
97 
98 MODULE(MODULE_CLASS_VFS, filecore, NULL);
99 
100 static struct sysctllog *filecore_sysctl_log;
101 
102 extern const struct vnodeopv_desc filecore_vnodeop_opv_desc;
103 
104 const struct vnodeopv_desc * const filecore_vnodeopv_descs[] = {
105 	&filecore_vnodeop_opv_desc,
106 	NULL,
107 };
108 
109 struct vfsops filecore_vfsops = {
110 	.vfs_name = MOUNT_FILECORE,
111 	.vfs_min_mount_data = sizeof (struct filecore_args),
112 	.vfs_mount = filecore_mount,
113 	.vfs_start = filecore_start,
114 	.vfs_unmount = filecore_unmount,
115 	.vfs_root = filecore_root,
116 	.vfs_quotactl = (void *)eopnotsupp,
117 	.vfs_statvfs = filecore_statvfs,
118 	.vfs_sync = filecore_sync,
119 	.vfs_vget = filecore_vget,
120 	.vfs_loadvnode = filecore_loadvnode,
121 	.vfs_fhtovp = filecore_fhtovp,
122 	.vfs_vptofh = filecore_vptofh,
123 	.vfs_init = filecore_init,
124 	.vfs_reinit = filecore_reinit,
125 	.vfs_done = filecore_done,
126 	.vfs_snapshot = (void *)eopnotsupp,
127 	.vfs_extattrctl = vfs_stdextattrctl,
128 	.vfs_suspendctl = (void *)eopnotsupp,
129 	.vfs_renamelock_enter = genfs_renamelock_enter,
130 	.vfs_renamelock_exit = genfs_renamelock_exit,
131 	.vfs_fsync = (void *)eopnotsupp,
132 	.vfs_opv_descs = filecore_vnodeopv_descs
133 };
134 
135 static int
filecore_modcmd(modcmd_t cmd,void * arg)136 filecore_modcmd(modcmd_t cmd, void *arg)
137 {
138 	int error;
139 
140 	switch (cmd) {
141 	case MODULE_CMD_INIT:
142 		error = vfs_attach(&filecore_vfsops);
143 		if (error != 0)
144 			break;
145 		sysctl_createv(&filecore_sysctl_log, 0, NULL, NULL,
146 			       CTLFLAG_PERMANENT,
147 			       CTLTYPE_NODE, "filecore",
148 			       SYSCTL_DESCR("Acorn FILECORE file system"),
149 			       NULL, 0, NULL, 0,
150 			       CTL_VFS, 19, CTL_EOL);
151 		/*
152 		 * XXX the "19" above could be dynamic, thereby eliminating
153 		 * one more instance of the "number to vfs" mapping problem,
154 		 * but "19" is the order as taken from sys/mount.h
155 		 */
156 		break;
157 	case MODULE_CMD_FINI:
158 		error = vfs_detach(&filecore_vfsops);
159 		if (error != 0)
160 			break;
161 		sysctl_teardown(&filecore_sysctl_log);
162 		break;
163 	default:
164 		error = ENOTTY;
165 		break;
166 	}
167 
168 	return (error);
169 }
170 
171 /*
172  * Called by vfs_mountroot when iso is going to be mounted as root.
173  *
174  * Name is updated by mount(8) after booting.
175  */
176 
177 static int filecore_mountfs(struct vnode *devvp, struct mount *mp,
178 		struct lwp *l, struct filecore_args *argp);
179 
180 #if 0
181 int
182 filecore_mountroot(void)
183 {
184 	struct mount *mp;
185 	extern struct vnode *rootvp;
186 	struct proc *p = curproc;	/* XXX */
187 	int error;
188 	struct filecore_args args;
189 
190 	if (device_class(root_device) != DV_DISK)
191 		return (ENODEV);
192 
193 	/*
194 	 * Get vnodes for swapdev and rootdev.
195 	 */
196 	if (bdevvp(rootdev, &rootvp))
197 		panic("filecore_mountroot: can't setup rootvp");
198 
199 	if ((error = vfs_rootmountalloc(MOUNT_FILECORE, "root_device", &mp)) != 0)
200 		return (error);
201 
202 	args.flags = FILECOREMNT_ROOT;
203 	if ((error = filecore_mountfs(rootvp, mp, p, &args)) != 0) {
204 		vfs_unbusy(mp, false, NULL);
205 		vfs_destroy(mp);
206 		return (error);
207 	}
208 	mountlist_append(mp);
209 	(void)filecore_statvfs(mp, &mp->mnt_stat, p);
210 	vfs_unbusy(mp, false, NULL);
211 	return (0);
212 }
213 #endif
214 
215 /*
216  * VFS Operations.
217  *
218  * mount system call
219  */
220 int
filecore_mount(struct mount * mp,const char * path,void * data,size_t * data_len)221 filecore_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
222 {
223 	struct lwp *l = curlwp;
224 	struct vnode *devvp;
225 	struct filecore_args *args = data;
226 	int error;
227 	struct filecore_mnt *fcmp = NULL;
228 
229 	if (args == NULL)
230 		return EINVAL;
231 	if (*data_len < sizeof *args)
232 		return EINVAL;
233 
234 	if (mp->mnt_flag & MNT_GETARGS) {
235 		fcmp = VFSTOFILECORE(mp);
236 		if (fcmp == NULL)
237 			return EIO;
238 		args->flags = fcmp->fc_mntflags;
239 		args->uid = fcmp->fc_uid;
240 		args->gid = fcmp->fc_gid;
241 		args->fspec = NULL;
242 		*data_len = sizeof *args;
243 		return 0;
244 	}
245 
246 	if ((mp->mnt_flag & MNT_RDONLY) == 0)
247 		return (EROFS);
248 
249 	if ((mp->mnt_flag & MNT_UPDATE) && args->fspec == NULL)
250 		return EINVAL;
251 
252 	/*
253 	 * Not an update, or updating the name: look up the name
254 	 * and verify that it refers to a sensible block device.
255 	 */
256 	error = namei_simple_user(args->fspec,
257 				NSM_FOLLOW_NOEMULROOT, &devvp);
258 	if (error != 0)
259 		return (error);
260 
261 	if (devvp->v_type != VBLK) {
262 		vrele(devvp);
263 		return ENOTBLK;
264 	}
265 	if (bdevsw_lookup(devvp->v_rdev) == NULL) {
266 		vrele(devvp);
267 		return ENXIO;
268 	}
269 	/*
270 	 * If mount by non-root, then verify that user has necessary
271 	 * permissions on the device.
272 	 */
273 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
274 	error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_MOUNT,
275 	    KAUTH_REQ_SYSTEM_MOUNT_DEVICE, mp, devvp, KAUTH_ARG(VREAD));
276 	VOP_UNLOCK(devvp);
277 	if (error) {
278 		vrele(devvp);
279 		return (error);
280 	}
281 	if ((mp->mnt_flag & MNT_UPDATE) == 0)
282 		error = filecore_mountfs(devvp, mp, l, args);
283 	else {
284 		fcmp = VFSTOFILECORE(mp);
285 		if (devvp != fcmp->fc_devvp)
286 			error = EINVAL;	/* needs translation */
287 		else
288 			vrele(devvp);
289 	}
290 	if (error) {
291 		vrele(devvp);
292 		return error;
293 	}
294 	fcmp = VFSTOFILECORE(mp);
295 	return set_statvfs_info(path, UIO_USERSPACE, args->fspec, UIO_USERSPACE,
296 	    mp->mnt_op->vfs_name, mp, l);
297 }
298 
299 /*
300  * Common code for mount and mountroot
301  */
302 static int
filecore_mountfs(struct vnode * devvp,struct mount * mp,struct lwp * l,struct filecore_args * argp)303 filecore_mountfs(struct vnode *devvp, struct mount *mp, struct lwp *l, struct filecore_args *argp)
304 {
305 	struct filecore_mnt *fcmp = (struct filecore_mnt *)0;
306 	struct buf *bp = NULL;
307 	dev_t dev = devvp->v_rdev;
308 	int error = EINVAL;
309 	int ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
310 	struct filecore_disc_record *fcdr;
311 	unsigned map;
312 	unsigned log2secsize;
313 
314 	if (!ronly)
315 		return EROFS;
316 
317 	if ((error = vinvalbuf(devvp, V_SAVE, l->l_cred, l, 0, 0)) != 0)
318 		return (error);
319 
320 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
321 	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, FSCRED);
322 	VOP_UNLOCK(devvp);
323 	if (error)
324 		return error;
325 
326 	/* Read the filecore boot block to check FS validity and to find the map */
327 	error = bread(devvp, FILECORE_BOOTBLOCK_BLKN,
328 			   FILECORE_BOOTBLOCK_SIZE, 0, &bp);
329 #ifdef FILECORE_DEBUG_BR
330 		printf("bread(%p, %x, %d, CRED, %p)=%d\n", devvp,
331 		       FILECORE_BOOTBLOCK_BLKN, FILECORE_BOOTBLOCK_SIZE,
332 		       bp, error);
333 #endif
334 	if (error != 0)
335 		goto out;
336 
337 	KASSERT(bp != NULL);
338 	if (filecore_bbchecksum(bp->b_data) != 0) {
339 		error = EINVAL;
340 		goto out;
341 	}
342 	fcdr = (struct filecore_disc_record *)((char *)(bp->b_data) +
343 	    FILECORE_BB_DISCREC);
344 	map = ((((8 << fcdr->log2secsize) - fcdr->zone_spare)
345 	    * (fcdr->nzones / 2) - 8 * FILECORE_DISCREC_SIZE)
346 	    << fcdr->log2bpmb) >> fcdr->log2secsize;
347 	log2secsize = fcdr->log2secsize;
348 #ifdef FILECORE_DEBUG_BR
349 	printf("brelse(%p) vf1\n", bp);
350 #endif
351 	brelse(bp, BC_AGE);
352 	bp = NULL;
353 
354 	/* Read the bootblock in the map */
355 	error = bread(devvp, map, 1 << log2secsize, 0, &bp);
356 #ifdef FILECORE_DEBUG_BR
357 		printf("bread(%p, %x, %d, CRED, %p)=%d\n", devvp,
358 		       map, 1 << log2secsize, bp, error);
359 #endif
360 	if (error != 0)
361 		goto out;
362        	fcdr = (struct filecore_disc_record *)((char *)(bp->b_data) + 4);
363 	fcmp = kmem_zalloc(sizeof(*fcmp), KM_SLEEP);
364 	if (fcdr->log2bpmb > fcdr->log2secsize)
365 		fcmp->log2bsize = fcdr->log2bpmb;
366 	else	fcmp->log2bsize = fcdr->log2secsize;
367 	fcmp->blksize = 1 << fcmp->log2bsize;
368 	memcpy(&fcmp->drec, fcdr, sizeof(*fcdr));
369 	fcmp->map = map;
370 	fcmp->idspz = ((8 << fcdr->log2secsize) - fcdr->zone_spare)
371 	    / (fcdr->idlen + 1);
372 	fcmp->mask = (1 << fcdr->idlen) - 1;
373 	if (fcdr->big_flag & 1) {
374 		fcmp->nblks = ((((u_int64_t)fcdr->disc_size_2) << 32)
375 		    + fcdr->disc_size) / fcmp->blksize;
376 	} else {
377 		fcmp->nblks=fcdr->disc_size / fcmp->blksize;
378 	}
379 
380 #ifdef FILECORE_DEBUG_BR
381 	printf("brelse(%p) vf2\n", bp);
382 #endif
383 	brelse(bp, BC_AGE);
384 	bp = NULL;
385 
386 	mp->mnt_data = fcmp;
387 	mp->mnt_stat.f_fsidx.__fsid_val[0] = (long)dev;
388 	mp->mnt_stat.f_fsidx.__fsid_val[1] = makefstype(MOUNT_FILECORE);
389 	mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0];
390 	mp->mnt_stat.f_namemax = 10;
391 	mp->mnt_flag |= MNT_LOCAL;
392 	mp->mnt_dev_bshift = fcdr->log2secsize;
393 	mp->mnt_fs_bshift = fcmp->log2bsize;
394 
395 	fcmp->fc_mountp = mp;
396 	fcmp->fc_dev = dev;
397 	fcmp->fc_devvp = devvp;
398 	fcmp->fc_mntflags = argp->flags;
399 	if (argp->flags & FILECOREMNT_USEUID) {
400 		fcmp->fc_uid = kauth_cred_getuid(l->l_cred);
401 		fcmp->fc_gid = kauth_cred_getgid(l->l_cred);
402 	} else {
403 		fcmp->fc_uid = argp->uid;
404 		fcmp->fc_gid = argp->gid;
405 	}
406 
407 	return 0;
408 out:
409 	if (bp) {
410 #ifdef FILECORE_DEBUG_BR
411 		printf("brelse(%p) vf3\n", bp);
412 #endif
413 		brelse(bp, 0);
414 	}
415 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
416 	(void)VOP_CLOSE(devvp, ronly ? FREAD : FREAD|FWRITE, NOCRED);
417 	VOP_UNLOCK(devvp);
418 	return error;
419 }
420 
421 /*
422  * Make a filesystem operational.
423  * Nothing to do at the moment.
424  */
425 /* ARGSUSED */
426 int
filecore_start(struct mount * mp,int flags)427 filecore_start(struct mount *mp, int flags)
428 {
429 	return 0;
430 }
431 
432 /*
433  * unmount system call
434  */
435 int
filecore_unmount(struct mount * mp,int mntflags)436 filecore_unmount(struct mount *mp, int mntflags)
437 {
438 	struct filecore_mnt *fcmp;
439 	int error, flags = 0;
440 
441 	if (mntflags & MNT_FORCE)
442 		flags |= FORCECLOSE;
443 	if ((error = vflush(mp, NULLVP, flags)) != 0)
444 		return (error);
445 
446 	fcmp = VFSTOFILECORE(mp);
447 
448 	if (fcmp->fc_devvp->v_type != VBAD)
449 		spec_node_setmountedfs(fcmp->fc_devvp, NULL);
450 	vn_lock(fcmp->fc_devvp, LK_EXCLUSIVE | LK_RETRY);
451 	error = VOP_CLOSE(fcmp->fc_devvp, FREAD, NOCRED);
452 	vput(fcmp->fc_devvp);
453 	kmem_free(fcmp, sizeof(*fcmp));
454 	mp->mnt_data = NULL;
455 	mp->mnt_flag &= ~MNT_LOCAL;
456 	return (error);
457 }
458 
459 /*
460  * Return root of a filesystem
461  */
462 int
filecore_root(struct mount * mp,struct vnode ** vpp)463 filecore_root(struct mount *mp, struct vnode **vpp)
464 {
465 	struct vnode *nvp;
466         int error;
467 
468         if ((error = VFS_VGET(mp, FILECORE_ROOTINO, &nvp)) != 0)
469                 return (error);
470         *vpp = nvp;
471         return (0);
472 }
473 
474 /*
475  * Get file system statistics.
476  */
477 int
filecore_statvfs(struct mount * mp,struct statvfs * sbp)478 filecore_statvfs(struct mount *mp, struct statvfs *sbp)
479 {
480 	struct filecore_mnt *fcmp = VFSTOFILECORE(mp);
481 
482 	sbp->f_bsize = fcmp->blksize;
483 	sbp->f_frsize = sbp->f_bsize; /* XXX */
484 	sbp->f_iosize = sbp->f_bsize;	/* XXX */
485 	sbp->f_blocks = fcmp->nblks;
486 	sbp->f_bfree = 0; /* total free blocks */
487 	sbp->f_bavail = 0; /* blocks free for non superuser */
488 	sbp->f_bresvd = 0; /* reserved blocks */
489 	sbp->f_files =  0; /* total files */
490 	sbp->f_ffree = 0; /* free file nodes for non superuser */
491 	sbp->f_favail = 0; /* free file nodes */
492 	sbp->f_fresvd = 0; /* reserved file nodes */
493 	copy_statvfs_info(sbp, mp);
494 	return 0;
495 }
496 
497 /* ARGSUSED */
498 int
filecore_sync(struct mount * mp,int waitfor,kauth_cred_t cred)499 filecore_sync(struct mount *mp, int waitfor, kauth_cred_t cred)
500 {
501 	return (0);
502 }
503 
504 /*
505  * File handle to vnode
506  *
507  * Have to be really careful about stale file handles:
508  * - check that the inode number is in range
509  * - call iget() to get the locked inode
510  * - check for an unallocated inode (i_mode == 0)
511  * - check that the generation number matches
512  */
513 
514 struct ifid {
515 	ushort		ifid_len;
516 	ushort		ifid_pad;
517 	u_int32_t	ifid_ino;
518 };
519 
520 /* ARGSUSED */
521 int
filecore_fhtovp(struct mount * mp,struct fid * fhp,struct vnode ** vpp)522 filecore_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
523 {
524 	struct ifid ifh;
525 	struct vnode *nvp;
526 	struct filecore_node *ip;
527 	int error;
528 
529 	if (fhp->fid_len != sizeof(struct ifid))
530 		return EINVAL;
531 
532 	memcpy(&ifh, fhp, sizeof(ifh));
533 	if ((error = VFS_VGET(mp, ifh.ifid_ino, &nvp)) != 0) {
534 		*vpp = NULLVP;
535 		return (error);
536 	}
537         ip = VTOI(nvp);
538         if (filecore_staleinode(ip)) {
539                 vput(nvp);
540                 *vpp = NULLVP;
541                 return (ESTALE);
542         }
543 	*vpp = nvp;
544 	return (0);
545 }
546 
547 /* This looks complicated. Look at other vgets as well as the iso9660 one.
548  *
549  * The filecore inode number is made up of 1 byte directory entry index and
550  * 3 bytes of the internal disc address of the directory. On a read-only
551  * filesystem this is unique. For a read-write version we may not be able to
552  * do vget, see msdosfs.
553  */
554 
555 int
filecore_vget(struct mount * mp,ino_t ino,struct vnode ** vpp)556 filecore_vget(struct mount *mp, ino_t ino, struct vnode **vpp)
557 {
558 	int error;
559 
560 	error = vcache_get(mp, &ino, sizeof(ino), vpp);
561 	if (error)
562 		return error;
563 	error = vn_lock(*vpp, LK_EXCLUSIVE);
564 	if (error) {
565 		vrele(*vpp);
566 		*vpp = NULL;
567 		return error;
568 	}
569 	return 0;
570 }
571 
572 /*
573  * Vnode pointer to File handle
574  */
575 /* ARGSUSED */
576 int
filecore_vptofh(struct vnode * vp,struct fid * fhp,size_t * fh_size)577 filecore_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size)
578 {
579 	struct filecore_node *ip = VTOI(vp);
580 	struct ifid ifh;
581 
582 	if (*fh_size < sizeof(struct ifid)) {
583 		*fh_size = sizeof(struct ifid);
584 		return E2BIG;
585 	}
586 	memset(&ifh, 0, sizeof(ifh));
587 	ifh.ifid_len = sizeof(struct ifid);
588 	ifh.ifid_ino = ip->i_number;
589 	memcpy(fhp, &ifh, sizeof(ifh));
590        	return 0;
591 }
592