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dksubr.c revision 1.15
      1 /* $NetBSD: dksubr.c,v 1.15 2005/06/28 20:23:02 drochner Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 1996, 1997, 1998, 1999, 2002 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Jason R. Thorpe and Roland C. Dowdeswell.
      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. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 __KERNEL_RCSID(0, "$NetBSD: dksubr.c,v 1.15 2005/06/28 20:23:02 drochner Exp $");
     41 
     42 #include <sys/param.h>
     43 #include <sys/systm.h>
     44 #include <sys/stat.h>
     45 #include <sys/proc.h>
     46 #include <sys/ioctl.h>
     47 #include <sys/device.h>
     48 #include <sys/disk.h>
     49 #include <sys/disklabel.h>
     50 #include <sys/buf.h>
     51 #include <sys/bufq.h>
     52 #include <sys/vnode.h>
     53 #include <sys/fcntl.h>
     54 #include <sys/namei.h>
     55 
     56 #include <dev/dkvar.h>
     57 
     58 int	dkdebug = 0;
     59 
     60 #ifdef DEBUG
     61 #define DKDB_FOLLOW	0x1
     62 #define DKDB_INIT	0x2
     63 #define DKDB_VNODE	0x4
     64 
     65 #define IFDEBUG(x,y)		if (dkdebug & (x)) y
     66 #define DPRINTF(x,y)		IFDEBUG(x, printf y)
     67 #define DPRINTF_FOLLOW(y)	DPRINTF(DKDB_FOLLOW, y)
     68 #else
     69 #define IFDEBUG(x,y)
     70 #define DPRINTF(x,y)
     71 #define DPRINTF_FOLLOW(y)
     72 #endif
     73 
     74 #define DKLABELDEV(dev)	\
     75 	(MAKEDISKDEV(major((dev)), DISKUNIT((dev)), RAW_PART))
     76 
     77 static void	dk_makedisklabel(struct dk_intf *, struct dk_softc *);
     78 
     79 void
     80 dk_sc_init(struct dk_softc *dksc, void *osc, char *xname)
     81 {
     82 
     83 	memset(dksc, 0x0, sizeof(*dksc));
     84 	dksc->sc_osc = osc;
     85 	strncpy(dksc->sc_xname, xname, DK_XNAME_SIZE);
     86 	dksc->sc_dkdev.dk_name = dksc->sc_xname;
     87 	lockinit(&dksc->sc_lock, PRIBIO, "dklk", 0, 0);
     88 }
     89 
     90 /* ARGSUSED */
     91 int
     92 dk_open(struct dk_intf *di, struct dk_softc *dksc, dev_t dev,
     93 	   int flags, int fmt, struct proc *p)
     94 {
     95 	struct	disklabel *lp = dksc->sc_dkdev.dk_label;
     96 	int	part = DISKPART(dev);
     97 	int	pmask = 1 << part;
     98 	int	ret = 0;
     99 
    100 	DPRINTF_FOLLOW(("dk_open(%s, %p, 0x%x, 0x%x)\n",
    101 	    di->di_dkname, dksc, dev, flags));
    102 
    103 	if ((ret = lockmgr(&dksc->sc_lock, LK_EXCLUSIVE, NULL)) != 0)
    104 		return ret;
    105 
    106 	part = DISKPART(dev);
    107 	pmask = 1 << part;
    108 
    109 	/*
    110 	 * If we're init'ed and there are no other open partitions then
    111 	 * update the in-core disklabel.
    112 	 */
    113 	if ((dksc->sc_flags & DKF_INITED) && dksc->sc_dkdev.dk_openmask == 0)
    114 		dk_getdisklabel(di, dksc, dev);
    115 
    116 	/* Fail if we can't find the partition. */
    117 	if ((part != RAW_PART) &&
    118 	    (((dksc->sc_flags & DKF_INITED) == 0) ||
    119 	    ((part >= lp->d_npartitions) ||
    120 	    (lp->d_partitions[part].p_fstype == FS_UNUSED)))) {
    121 		ret = ENXIO;
    122 		goto done;
    123 	}
    124 
    125 	/* Mark our unit as open. */
    126 	switch (fmt) {
    127 	case S_IFCHR:
    128 		dksc->sc_dkdev.dk_copenmask |= pmask;
    129 		break;
    130 	case S_IFBLK:
    131 		dksc->sc_dkdev.dk_bopenmask |= pmask;
    132 		break;
    133 	}
    134 
    135 	dksc->sc_dkdev.dk_openmask =
    136 	    dksc->sc_dkdev.dk_copenmask | dksc->sc_dkdev.dk_bopenmask;
    137 
    138 done:
    139 	lockmgr(&dksc->sc_lock, LK_RELEASE, NULL);
    140 	return ret;
    141 }
    142 
    143 /* ARGSUSED */
    144 int
    145 dk_close(struct dk_intf *di, struct dk_softc *dksc, dev_t dev,
    146 	    int flags, int fmt, struct proc *p)
    147 {
    148 	int	part = DISKPART(dev);
    149 	int	pmask = 1 << part;
    150 	int	ret;
    151 
    152 	DPRINTF_FOLLOW(("dk_close(%s, %p, 0x%x, 0x%x)\n",
    153 	    di->di_dkname, dksc, dev, flags));
    154 
    155 	if ((ret = lockmgr(&dksc->sc_lock, LK_EXCLUSIVE, NULL)) != 0)
    156 		return ret;
    157 
    158 	switch (fmt) {
    159 	case S_IFCHR:
    160 		dksc->sc_dkdev.dk_copenmask &= ~pmask;
    161 		break;
    162 	case S_IFBLK:
    163 		dksc->sc_dkdev.dk_bopenmask &= ~pmask;
    164 		break;
    165 	}
    166 	dksc->sc_dkdev.dk_openmask =
    167 	    dksc->sc_dkdev.dk_copenmask | dksc->sc_dkdev.dk_bopenmask;
    168 
    169 	lockmgr(&dksc->sc_lock, LK_RELEASE, NULL);
    170 	return 0;
    171 }
    172 
    173 void
    174 dk_strategy(struct dk_intf *di, struct dk_softc *dksc, struct buf *bp)
    175 {
    176 	int	s;
    177 	int	wlabel;
    178 
    179 	DPRINTF_FOLLOW(("dk_strategy(%s, %p, %p)\n",
    180 	    di->di_dkname, dksc, bp));
    181 
    182 	if (!(dksc->sc_flags & DKF_INITED)) {
    183 		DPRINTF_FOLLOW(("dk_stragy: not inited\n"));
    184 		bp->b_error  = ENXIO;
    185 		bp->b_flags |= B_ERROR;
    186 		biodone(bp);
    187 		return;
    188 	}
    189 
    190 	/* XXX look for some more errors, c.f. ld.c */
    191 
    192 	bp->b_resid = bp->b_bcount;
    193 
    194 	/* If there is nothing to do, then we are done */
    195 	if (bp->b_bcount == 0) {
    196 		biodone(bp);
    197 		return;
    198 	}
    199 
    200 	wlabel = dksc->sc_flags & (DKF_WLABEL|DKF_LABELLING);
    201 	if (DISKPART(bp->b_dev) != RAW_PART &&
    202 	    bounds_check_with_label(&dksc->sc_dkdev, bp, wlabel) <= 0) {
    203 		biodone(bp);
    204 		return;
    205 	}
    206 
    207 	/*
    208 	 * Start the unit by calling the start routine
    209 	 * provided by the individual driver.
    210 	 */
    211 	s = splbio();
    212 	BUFQ_PUT(&dksc->sc_bufq, bp);
    213 	dk_start(di, dksc);
    214 	splx(s);
    215 	return;
    216 }
    217 
    218 void
    219 dk_start(struct dk_intf *di, struct dk_softc *dksc)
    220 {
    221 	struct	buf *bp;
    222 
    223 	DPRINTF_FOLLOW(("dk_start(%s, %p)\n", di->di_dkname, dksc));
    224 
    225 	/* Process the work queue */
    226 	while ((bp = BUFQ_GET(&dksc->sc_bufq)) != NULL) {
    227 		if (di->di_diskstart(dksc, bp) != 0) {
    228 			BUFQ_PUT(&dksc->sc_bufq, bp);
    229 			break;
    230 		}
    231 	}
    232 }
    233 
    234 void
    235 dk_iodone(struct dk_intf *di, struct dk_softc *dksc)
    236 {
    237 
    238 	DPRINTF_FOLLOW(("dk_iodone(%s, %p)\n", di->di_dkname, dksc));
    239 
    240 	/* We kick the queue in case we are able to get more work done */
    241 	dk_start(di, dksc);
    242 }
    243 
    244 int
    245 dk_size(struct dk_intf *di, struct dk_softc *dksc, dev_t dev)
    246 {
    247 	struct	disklabel *lp;
    248 	int	is_open;
    249 	int	part;
    250 	int	size;
    251 
    252 	if ((dksc->sc_flags & DKF_INITED) == 0)
    253 		return -1;
    254 
    255 	part = DISKPART(dev);
    256 	is_open = dksc->sc_dkdev.dk_openmask & (1 << part);
    257 
    258 	if (!is_open && di->di_open(dev, 0, S_IFBLK, curproc))
    259 		return -1;
    260 
    261 	lp = dksc->sc_dkdev.dk_label;
    262 	if (lp->d_partitions[part].p_fstype != FS_SWAP)
    263 		size = -1;
    264 	else
    265 		size = lp->d_partitions[part].p_size *
    266 		    (lp->d_secsize / DEV_BSIZE);
    267 
    268 	if (!is_open && di->di_close(dev, 0, S_IFBLK, curproc))
    269 		return 1;
    270 
    271 	return size;
    272 }
    273 
    274 int
    275 dk_ioctl(struct dk_intf *di, struct dk_softc *dksc, dev_t dev,
    276 	    u_long cmd, caddr_t data, int flag, struct proc *p)
    277 {
    278 	struct	disklabel *lp;
    279 #ifdef __HAVE_OLD_DISKLABEL
    280 	struct	disklabel newlabel;
    281 #endif
    282 	int	error = 0;
    283 
    284 	DPRINTF_FOLLOW(("dk_ioctl(%s, %p, 0x%x, 0x%lx)\n",
    285 	    di->di_dkname, dksc, dev, cmd));
    286 
    287 	/* ensure that the pseudo disk is open for writes for these commands */
    288 	switch (cmd) {
    289 	case DIOCSDINFO:
    290 	case DIOCWDINFO:
    291 #ifdef __HAVE_OLD_DISKLABEL
    292 	case ODIOCSDINFO:
    293 	case ODIOCWDINFO:
    294 #endif
    295 	case DIOCWLABEL:
    296 		if ((flag & FWRITE) == 0)
    297 			return EBADF;
    298 	}
    299 
    300 	/* ensure that the pseudo-disk is initialized for these */
    301 	switch (cmd) {
    302 	case DIOCGDINFO:
    303 	case DIOCSDINFO:
    304 	case DIOCWDINFO:
    305 	case DIOCGPART:
    306 	case DIOCWLABEL:
    307 	case DIOCGDEFLABEL:
    308 #ifdef __HAVE_OLD_DISKLABEL
    309 	case ODIOCGDINFO:
    310 	case ODIOCSDINFO:
    311 	case ODIOCWDINFO:
    312 	case ODIOCGDEFLABEL:
    313 #endif
    314 		if ((dksc->sc_flags & DKF_INITED) == 0)
    315 			return ENXIO;
    316 	}
    317 
    318 	switch (cmd) {
    319 	case DIOCGDINFO:
    320 		*(struct disklabel *)data = *(dksc->sc_dkdev.dk_label);
    321 		break;
    322 
    323 #ifdef __HAVE_OLD_DISKLABEL
    324 	case ODIOCGDINFO:
    325 		newlabel = *(dksc->sc_dkdev.dk_label);
    326 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
    327 			return ENOTTY;
    328 		memcpy(data, &newlabel, sizeof (struct olddisklabel));
    329 		break;
    330 #endif
    331 
    332 	case DIOCGPART:
    333 		((struct partinfo *)data)->disklab = dksc->sc_dkdev.dk_label;
    334 		((struct partinfo *)data)->part =
    335 		    &dksc->sc_dkdev.dk_label->d_partitions[DISKPART(dev)];
    336 		break;
    337 
    338 	case DIOCWDINFO:
    339 	case DIOCSDINFO:
    340 #ifdef __HAVE_OLD_DISKLABEL
    341 	case ODIOCWDINFO:
    342 	case ODIOCSDINFO:
    343 #endif
    344 #ifdef __HAVE_OLD_DISKLABEL
    345 		if (cmd == ODIOCSDINFO || cmd == ODIOCWDINFO) {
    346 			memset(&newlabel, 0, sizeof newlabel);
    347 			memcpy(&newlabel, data, sizeof (struct olddisklabel));
    348 			lp = &newlabel;
    349 		} else
    350 #endif
    351 		lp = (struct disklabel *)data;
    352 
    353 		dksc->sc_flags |= DKF_LABELLING;
    354 
    355 		error = setdisklabel(dksc->sc_dkdev.dk_label,
    356 		    lp, 0, dksc->sc_dkdev.dk_cpulabel);
    357 		if (error == 0) {
    358 			if (cmd == DIOCWDINFO
    359 #ifdef __HAVE_OLD_DISKLABEL
    360 			    || cmd == ODIOCWDINFO
    361 #endif
    362 			   )
    363 				error = writedisklabel(DKLABELDEV(dev),
    364 				    di->di_strategy, dksc->sc_dkdev.dk_label,
    365 				    dksc->sc_dkdev.dk_cpulabel);
    366 		}
    367 
    368 		dksc->sc_flags &= ~DKF_LABELLING;
    369 		break;
    370 
    371 	case DIOCWLABEL:
    372 		if (*(int *)data != 0)
    373 			dksc->sc_flags |= DKF_WLABEL;
    374 		else
    375 			dksc->sc_flags &= ~DKF_WLABEL;
    376 		break;
    377 
    378 	case DIOCGDEFLABEL:
    379 		dk_getdefaultlabel(di, dksc, (struct disklabel *)data);
    380 		break;
    381 
    382 #ifdef __HAVE_OLD_DISKLABEL
    383 	case ODIOCGDEFLABEL:
    384 		dk_getdefaultlabel(di, dksc, &newlabel);
    385 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
    386 			return ENOTTY;
    387 		memcpy(data, &newlabel, sizeof (struct olddisklabel));
    388 		break;
    389 #endif
    390 
    391 	default:
    392 		error = ENOTTY;
    393 	}
    394 
    395 	return error;
    396 }
    397 
    398 /*
    399  * dk_dump dumps all of physical memory into the partition specified.
    400  * This requires substantially more framework than {s,w}ddump, and hence
    401  * is probably much more fragile.
    402  *
    403  * XXX: we currently do not implement this.
    404  */
    405 
    406 #define DKF_READYFORDUMP	(DKF_INITED|DKF_TAKEDUMP)
    407 #define DKFF_READYFORDUMP(x)	(((x) & DKF_READYFORDUMP) == DKF_READYFORDUMP)
    408 static volatile int	dk_dumping = 0;
    409 
    410 /* ARGSUSED */
    411 int
    412 dk_dump(struct dk_intf *di, struct dk_softc *dksc, dev_t dev,
    413 	   daddr_t blkno, caddr_t va, size_t size)
    414 {
    415 
    416 	/*
    417 	 * ensure that we consider this device to be safe for dumping,
    418 	 * and that the device is configured.
    419 	 */
    420 	if (!DKFF_READYFORDUMP(dksc->sc_flags))
    421 		return ENXIO;
    422 
    423 	/* ensure that we are not already dumping */
    424 	if (dk_dumping)
    425 		return EFAULT;
    426 	dk_dumping = 1;
    427 
    428 	/* XXX: unimplemented */
    429 
    430 	dk_dumping = 0;
    431 
    432 	/* XXX: actually for now, we are going to leave this alone */
    433 	return ENXIO;
    434 }
    435 
    436 /* ARGSUSED */
    437 void
    438 dk_getdefaultlabel(struct dk_intf *di, struct dk_softc *dksc,
    439 		      struct disklabel *lp)
    440 {
    441 	struct dk_geom *pdg = &dksc->sc_geom;
    442 
    443 	memset(lp, 0, sizeof(*lp));
    444 
    445 	lp->d_secperunit = dksc->sc_size;
    446 	lp->d_secsize = pdg->pdg_secsize;
    447 	lp->d_nsectors = pdg->pdg_nsectors;
    448 	lp->d_ntracks = pdg->pdg_ntracks;
    449 	lp->d_ncylinders = pdg->pdg_ncylinders;
    450 	lp->d_secpercyl = lp->d_ntracks * lp->d_nsectors;
    451 
    452 	strncpy(lp->d_typename, di->di_dkname, sizeof(lp->d_typename));
    453 	lp->d_type = di->di_dtype;
    454 	strncpy(lp->d_packname, "fictitious", sizeof(lp->d_packname));
    455 	lp->d_rpm = 3600;
    456 	lp->d_interleave = 1;
    457 	lp->d_flags = 0;
    458 
    459 	lp->d_partitions[RAW_PART].p_offset = 0;
    460 	lp->d_partitions[RAW_PART].p_size = dksc->sc_size;
    461 	lp->d_partitions[RAW_PART].p_fstype = FS_UNUSED;
    462 	lp->d_npartitions = RAW_PART + 1;
    463 
    464 	lp->d_magic = DISKMAGIC;
    465 	lp->d_magic2 = DISKMAGIC;
    466 	lp->d_checksum = dkcksum(dksc->sc_dkdev.dk_label);
    467 }
    468 
    469 /* ARGSUSED */
    470 void
    471 dk_getdisklabel(struct dk_intf *di, struct dk_softc *dksc, dev_t dev)
    472 {
    473 	struct	 disklabel *lp = dksc->sc_dkdev.dk_label;
    474 	struct	 cpu_disklabel *clp = dksc->sc_dkdev.dk_cpulabel;
    475 	struct	 partition *pp;
    476 	int	 i;
    477 	const char	*errstring;
    478 
    479 	memset(clp, 0x0, sizeof(*clp));
    480 	dk_getdefaultlabel(di, dksc, lp);
    481 	errstring = readdisklabel(DKLABELDEV(dev), di->di_strategy,
    482 	    dksc->sc_dkdev.dk_label, dksc->sc_dkdev.dk_cpulabel);
    483 	if (errstring) {
    484 		dk_makedisklabel(di, dksc);
    485 		if (dksc->sc_flags & DKF_WARNLABEL)
    486 			printf("%s: %s\n", dksc->sc_xname, errstring);
    487 		return;
    488 	}
    489 
    490 	if ((dksc->sc_flags & DKF_LABELSANITY) == 0)
    491 		return;
    492 
    493 	/* Sanity check */
    494 	if (lp->d_secperunit != dksc->sc_size)
    495 		printf("WARNING: %s: total sector size in disklabel (%d) "
    496 		    "!= the size of %s (%lu)\n", dksc->sc_xname,
    497 		    lp->d_secperunit, di->di_dkname, (u_long)dksc->sc_size);
    498 
    499 	for (i=0; i < lp->d_npartitions; i++) {
    500 		pp = &lp->d_partitions[i];
    501 		if (pp->p_offset + pp->p_size > dksc->sc_size)
    502 			printf("WARNING: %s: end of partition `%c' exceeds "
    503 			    "the size of %s (%lu)\n", dksc->sc_xname,
    504 			    'a' + i, di->di_dkname, (u_long)dksc->sc_size);
    505 	}
    506 }
    507 
    508 /* ARGSUSED */
    509 static void
    510 dk_makedisklabel(struct dk_intf *di, struct dk_softc *dksc)
    511 {
    512 	struct	disklabel *lp = dksc->sc_dkdev.dk_label;
    513 
    514 	lp->d_partitions[RAW_PART].p_fstype = FS_BSDFFS;
    515 	strncpy(lp->d_packname, "default label", sizeof(lp->d_packname));
    516 	lp->d_checksum = dkcksum(lp);
    517 }
    518 
    519 /* This function is taken from ccd.c:1.76  --rcd */
    520 
    521 /*
    522  * XXX this function looks too generic for dksubr.c, shouldn't we
    523  *     put it somewhere better?
    524  */
    525 
    526 /*
    527  * Lookup the provided name in the filesystem.  If the file exists,
    528  * is a valid block device, and isn't being used by anyone else,
    529  * set *vpp to the file's vnode.
    530  */
    531 int
    532 dk_lookup(path, p, vpp)
    533 	const char *path;
    534 	struct proc *p;
    535 	struct vnode **vpp;	/* result */
    536 {
    537 	struct nameidata nd;
    538 	struct vnode *vp;
    539 	struct vattr va;
    540 	int error;
    541 
    542 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, path, p);
    543 	if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) {
    544 		DPRINTF((DKDB_FOLLOW|DKDB_INIT),
    545 		    ("dk_lookup: vn_open error = %d\n", error));
    546 		return (error);
    547 	}
    548 	vp = nd.ni_vp;
    549 
    550 	if (vp->v_usecount > 1) {
    551 		VOP_UNLOCK(vp, 0);
    552 		(void)vn_close(vp, FREAD|FWRITE, p->p_ucred, p);
    553 		return (EBUSY);
    554 	}
    555 
    556 	if ((error = VOP_GETATTR(vp, &va, p->p_ucred, p)) != 0) {
    557 		DPRINTF((DKDB_FOLLOW|DKDB_INIT),
    558 		    ("dk_lookup: getattr error = %d\n", error));
    559 		VOP_UNLOCK(vp, 0);
    560 		(void)vn_close(vp, FREAD|FWRITE, p->p_ucred, p);
    561 		return (error);
    562 	}
    563 
    564 	/* XXX: eventually we should handle VREG, too. */
    565 	if (va.va_type != VBLK) {
    566 		VOP_UNLOCK(vp, 0);
    567 		(void)vn_close(vp, FREAD|FWRITE, p->p_ucred, p);
    568 		return (ENOTBLK);
    569 	}
    570 
    571 	IFDEBUG(DKDB_VNODE, vprint("dk_lookup: vnode info", vp));
    572 
    573 	VOP_UNLOCK(vp, 0);
    574 	*vpp = vp;
    575 	return (0);
    576 }
    577