1 /* $NetBSD: coda_vfsops.c,v 1.90 2022/03/28 12:37:46 riastradh Exp $ */
2
3 /*
4 *
5 * Coda: an Experimental Distributed File System
6 * Release 3.1
7 *
8 * Copyright (c) 1987-1998 Carnegie Mellon University
9 * All Rights Reserved
10 *
11 * Permission to use, copy, modify and distribute this software and its
12 * documentation is hereby granted, provided that both the copyright
13 * notice and this permission notice appear in all copies of the
14 * software, derivative works or modified versions, and any portions
15 * thereof, and that both notices appear in supporting documentation, and
16 * that credit is given to Carnegie Mellon University in all documents
17 * and publicity pertaining to direct or indirect use of this code or its
18 * derivatives.
19 *
20 * CODA IS AN EXPERIMENTAL SOFTWARE SYSTEM AND IS KNOWN TO HAVE BUGS,
21 * SOME OF WHICH MAY HAVE SERIOUS CONSEQUENCES. CARNEGIE MELLON ALLOWS
22 * FREE USE OF THIS SOFTWARE IN ITS "AS IS" CONDITION. CARNEGIE MELLON
23 * DISCLAIMS ANY LIABILITY OF ANY KIND FOR ANY DAMAGES WHATSOEVER
24 * RESULTING DIRECTLY OR INDIRECTLY FROM THE USE OF THIS SOFTWARE OR OF
25 * ANY DERIVATIVE WORK.
26 *
27 * Carnegie Mellon encourages users of this software to return any
28 * improvements or extensions that they make, and to grant Carnegie
29 * Mellon the rights to redistribute these changes without encumbrance.
30 *
31 * @(#) cfs/coda_vfsops.c,v 1.1.1.1 1998/08/29 21:26:45 rvb Exp $
32 */
33
34 /*
35 * Mach Operating System
36 * Copyright (c) 1989 Carnegie-Mellon University
37 * All rights reserved. The CMU software License Agreement specifies
38 * the terms and conditions for use and redistribution.
39 */
40
41 /*
42 * This code was written for the Coda file system at Carnegie Mellon
43 * University. Contributers include David Steere, James Kistler, and
44 * M. Satyanarayanan.
45 */
46
47 #include <sys/cdefs.h>
48 __KERNEL_RCSID(0, "$NetBSD: coda_vfsops.c,v 1.90 2022/03/28 12:37:46 riastradh Exp $");
49
50 #include <sys/param.h>
51 #include <sys/systm.h>
52 #include <sys/sysctl.h>
53 #include <sys/malloc.h>
54 #include <sys/conf.h>
55 #include <sys/namei.h>
56 #include <sys/dirent.h>
57 #include <sys/mount.h>
58 #include <sys/proc.h>
59 #include <sys/select.h>
60 #include <sys/kauth.h>
61 #include <sys/module.h>
62
63 #include <coda/coda.h>
64 #include <coda/cnode.h>
65 #include <coda/coda_vfsops.h>
66 #include <coda/coda_venus.h>
67 #include <coda/coda_subr.h>
68 #include <coda/coda_opstats.h>
69 /* for VN_RDEV */
70 #include <miscfs/specfs/specdev.h>
71 #include <miscfs/genfs/genfs.h>
72
73 MODULE(MODULE_CLASS_VFS, coda, "vcoda");
74
75 #define ENTRY if(coda_vfsop_print_entry) myprintf(("Entered %s\n",__func__))
76
77 extern struct vnode *coda_ctlvp;
78 extern struct coda_mntinfo coda_mnttbl[NVCODA]; /* indexed by minor device number */
79
80 /* structure to keep statistics of internally generated/satisfied calls */
81
82 struct coda_op_stats coda_vfsopstats[CODA_VFSOPS_SIZE];
83
84 #define MARK_ENTRY(op) (coda_vfsopstats[op].entries++)
85 #define MARK_INT_SAT(op) (coda_vfsopstats[op].sat_intrn++)
86 #define MARK_INT_FAIL(op) (coda_vfsopstats[op].unsat_intrn++)
87 #define MRAK_INT_GEN(op) (coda_vfsopstats[op].gen_intrn++)
88
89 extern const struct cdevsw vcoda_cdevsw;
90 extern const struct vnodeopv_desc coda_vnodeop_opv_desc;
91
92 const struct vnodeopv_desc * const coda_vnodeopv_descs[] = {
93 &coda_vnodeop_opv_desc,
94 NULL,
95 };
96
97 struct vfsops coda_vfsops = {
98 .vfs_name = MOUNT_CODA,
99 .vfs_min_mount_data = 256,
100 /* This is the pathname, unlike every other fs */
101 .vfs_mount = coda_mount,
102 .vfs_start = coda_start,
103 .vfs_unmount = coda_unmount,
104 .vfs_root = coda_root,
105 .vfs_quotactl = (void *)eopnotsupp,
106 .vfs_statvfs = coda_nb_statvfs,
107 .vfs_sync = coda_sync,
108 .vfs_vget = coda_vget,
109 .vfs_loadvnode = coda_loadvnode,
110 .vfs_fhtovp = (void *)eopnotsupp,
111 .vfs_vptofh = (void *)eopnotsupp,
112 .vfs_init = coda_init,
113 .vfs_done = coda_done,
114 .vfs_mountroot = (void *)eopnotsupp,
115 .vfs_snapshot = (void *)eopnotsupp,
116 .vfs_extattrctl = vfs_stdextattrctl,
117 .vfs_suspendctl = genfs_suspendctl,
118 .vfs_renamelock_enter = genfs_renamelock_enter,
119 .vfs_renamelock_exit = genfs_renamelock_exit,
120 .vfs_fsync = (void *)eopnotsupp,
121 .vfs_opv_descs = coda_vnodeopv_descs
122 };
123
124 static int
coda_modcmd(modcmd_t cmd,void * arg)125 coda_modcmd(modcmd_t cmd, void *arg)
126 {
127
128 switch (cmd) {
129 case MODULE_CMD_INIT:
130 return vfs_attach(&coda_vfsops);
131 case MODULE_CMD_FINI:
132 return vfs_detach(&coda_vfsops);
133 default:
134 return ENOTTY;
135 }
136 }
137
138 int
coda_vfsopstats_init(void)139 coda_vfsopstats_init(void)
140 {
141 int i;
142
143 for (i=0;i<CODA_VFSOPS_SIZE;i++) {
144 coda_vfsopstats[i].opcode = i;
145 coda_vfsopstats[i].entries = 0;
146 coda_vfsopstats[i].sat_intrn = 0;
147 coda_vfsopstats[i].unsat_intrn = 0;
148 coda_vfsopstats[i].gen_intrn = 0;
149 }
150
151 return 0;
152 }
153
154 /*
155 * cfs mount vfsop
156 * Set up mount info record and attach it to vfs struct.
157 */
158 /*ARGSUSED*/
159 int
coda_mount(struct mount * vfsp,const char * path,void * data,size_t * data_len)160 coda_mount(struct mount *vfsp, /* Allocated and initialized by mount(2) */
161 const char *path, /* path covered: ignored by the fs-layer */
162 void *data, /* Need to define a data type for this in netbsd? */
163 size_t *data_len)
164 {
165 struct lwp *l = curlwp;
166 struct vnode *dvp;
167 struct cnode *cp;
168 dev_t dev;
169 struct coda_mntinfo *mi;
170 struct vnode *rtvp;
171 const struct cdevsw *cdev;
172 CodaFid rootfid = INVAL_FID;
173 CodaFid ctlfid = CTL_FID;
174 int error;
175
176 if (data == NULL)
177 return EINVAL;
178 if (vfsp->mnt_flag & MNT_GETARGS)
179 return EINVAL;
180 ENTRY;
181
182 coda_vfsopstats_init();
183 coda_vnodeopstats_init();
184
185 MARK_ENTRY(CODA_MOUNT_STATS);
186 if (CODA_MOUNTED(vfsp)) {
187 MARK_INT_FAIL(CODA_MOUNT_STATS);
188 return(EBUSY);
189 }
190
191 /* Validate mount device. Similar to getmdev(). */
192
193 /*
194 * XXX: coda passes the mount device as the entire mount args,
195 * All other fs pass a structure contining a pointer.
196 * In order to get sys_mount() to do the copyin() we've set a
197 * fixed default size for the filename buffer.
198 */
199 /* Ensure that namei() doesn't run off the filename buffer */
200 if (*data_len < 1 || *data_len > PATH_MAX ||
201 strnlen(data, *data_len) >= *data_len) {
202 MARK_INT_FAIL(CODA_MOUNT_STATS);
203 return EINVAL;
204 }
205 error = namei_simple_kernel((char *)data, NSM_FOLLOW_NOEMULROOT,
206 &dvp);
207
208 if (error) {
209 MARK_INT_FAIL(CODA_MOUNT_STATS);
210 return (error);
211 }
212 if (dvp->v_type != VCHR) {
213 MARK_INT_FAIL(CODA_MOUNT_STATS);
214 vrele(dvp);
215 return(ENXIO);
216 }
217 dev = dvp->v_rdev;
218 vrele(dvp);
219 cdev = cdevsw_lookup(dev);
220 if (cdev == NULL) {
221 MARK_INT_FAIL(CODA_MOUNT_STATS);
222 return(ENXIO);
223 }
224
225 /*
226 * See if the device table matches our expectations.
227 */
228 if (cdev != &vcoda_cdevsw)
229 {
230 MARK_INT_FAIL(CODA_MOUNT_STATS);
231 return(ENXIO);
232 }
233
234 if (minor(dev) >= NVCODA) {
235 MARK_INT_FAIL(CODA_MOUNT_STATS);
236 return(ENXIO);
237 }
238
239 /*
240 * Initialize the mount record and link it to the vfs struct
241 */
242 mi = &coda_mnttbl[minor(dev)];
243
244 if (!VC_OPEN(&mi->mi_vcomm)) {
245 MARK_INT_FAIL(CODA_MOUNT_STATS);
246 return(ENODEV);
247 }
248
249 /* No initialization (here) of mi_vcomm! */
250 vfsp->mnt_data = mi;
251 vfsp->mnt_stat.f_fsidx.__fsid_val[0] = 0;
252 vfsp->mnt_stat.f_fsidx.__fsid_val[1] = makefstype(MOUNT_CODA);
253 vfsp->mnt_stat.f_fsid = vfsp->mnt_stat.f_fsidx.__fsid_val[0];
254 vfsp->mnt_stat.f_namemax = CODA_MAXNAMLEN;
255 mi->mi_vfsp = vfsp;
256
257 /*
258 * Make a root vnode to placate the Vnode interface, but don't
259 * actually make the CODA_ROOT call to venus until the first call
260 * to coda_root in case a server is down while venus is starting.
261 */
262 cp = make_coda_node(&rootfid, vfsp, VDIR);
263 rtvp = CTOV(cp);
264 rtvp->v_vflag |= VV_ROOT;
265
266 cp = make_coda_node(&ctlfid, vfsp, VCHR);
267
268 coda_ctlvp = CTOV(cp);
269
270 /* Add vfs and rootvp to chain of vfs hanging off mntinfo */
271 mi->mi_vfsp = vfsp;
272 mi->mi_rootvp = rtvp;
273
274 /* set filesystem block size */
275 vfsp->mnt_stat.f_bsize = 8192; /* XXX -JJK */
276 vfsp->mnt_stat.f_frsize = 8192; /* XXX -JJK */
277
278 /* error is currently guaranteed to be zero, but in case some
279 code changes... */
280 CODADEBUG(1,
281 myprintf(("coda_mount returned %d\n",error)););
282 if (error)
283 MARK_INT_FAIL(CODA_MOUNT_STATS);
284 else
285 MARK_INT_SAT(CODA_MOUNT_STATS);
286
287 return set_statvfs_info("/coda", UIO_SYSSPACE, "CODA", UIO_SYSSPACE,
288 vfsp->mnt_op->vfs_name, vfsp, l);
289 }
290
291 int
coda_start(struct mount * vfsp,int flags)292 coda_start(struct mount *vfsp, int flags)
293 {
294 ENTRY;
295 vftomi(vfsp)->mi_started = 1;
296 return (0);
297 }
298
299 int
coda_unmount(struct mount * vfsp,int mntflags)300 coda_unmount(struct mount *vfsp, int mntflags)
301 {
302 struct coda_mntinfo *mi = vftomi(vfsp);
303 int active, error = 0;
304
305 ENTRY;
306 MARK_ENTRY(CODA_UMOUNT_STATS);
307 if (!CODA_MOUNTED(vfsp)) {
308 MARK_INT_FAIL(CODA_UMOUNT_STATS);
309 return(EINVAL);
310 }
311
312 if (mi->mi_vfsp == vfsp) { /* We found the victim */
313 if (!IS_UNMOUNTING(VTOC(mi->mi_rootvp)))
314 return (EBUSY); /* Venus is still running */
315
316 #ifdef DEBUG
317 printf("coda_unmount: ROOT: vp %p, cp %p\n", mi->mi_rootvp, VTOC(mi->mi_rootvp));
318 #endif
319 mi->mi_started = 0;
320
321 vrele(mi->mi_rootvp);
322 vrele(coda_ctlvp);
323
324 active = coda_kill(vfsp, NOT_DOWNCALL);
325 mi->mi_rootvp->v_vflag &= ~VV_ROOT;
326 error = vflush(mi->mi_vfsp, NULLVP, FORCECLOSE);
327 printf("coda_unmount: active = %d, vflush active %d\n", active, error);
328 error = 0;
329
330 /* I'm going to take this out to allow lookups to go through. I'm
331 * not sure it's important anyway. -- DCS 2/2/94
332 */
333 /* vfsp->VFS_DATA = NULL; */
334
335 /* No more vfsp's to hold onto */
336 mi->mi_vfsp = NULL;
337 mi->mi_rootvp = NULL;
338
339 if (error)
340 MARK_INT_FAIL(CODA_UMOUNT_STATS);
341 else
342 MARK_INT_SAT(CODA_UMOUNT_STATS);
343
344 return(error);
345 }
346 return (EINVAL);
347 }
348
349 /*
350 * find root of cfs
351 */
352 int
coda_root(struct mount * vfsp,int lktype,struct vnode ** vpp)353 coda_root(struct mount *vfsp, int lktype, struct vnode **vpp)
354 {
355 struct coda_mntinfo *mi = vftomi(vfsp);
356 int error;
357 struct lwp *l = curlwp; /* XXX - bnoble */
358 CodaFid VFid;
359 static const CodaFid invalfid = INVAL_FID;
360
361 ENTRY;
362 MARK_ENTRY(CODA_ROOT_STATS);
363
364 if (vfsp == mi->mi_vfsp) {
365 if (memcmp(&VTOC(mi->mi_rootvp)->c_fid, &invalfid, sizeof(CodaFid)))
366 { /* Found valid root. */
367 *vpp = mi->mi_rootvp;
368 /* On Mach, this is vref. On NetBSD, VOP_LOCK */
369 vref(*vpp);
370 vn_lock(*vpp, lktype);
371 MARK_INT_SAT(CODA_ROOT_STATS);
372 return(0);
373 }
374 }
375
376 error = venus_root(vftomi(vfsp), l->l_cred, l->l_proc, &VFid);
377
378 if (!error) {
379 struct cnode *cp = VTOC(mi->mi_rootvp);
380
381 /*
382 * Save the new rootfid in the cnode, and rekey the cnode
383 * with the new fid key.
384 */
385 error = vcache_rekey_enter(vfsp, mi->mi_rootvp,
386 &invalfid, sizeof(CodaFid), &VFid, sizeof(CodaFid));
387 if (error)
388 goto exit;
389 cp->c_fid = VFid;
390 vcache_rekey_exit(vfsp, mi->mi_rootvp,
391 &invalfid, sizeof(CodaFid), &cp->c_fid, sizeof(CodaFid));
392
393 *vpp = mi->mi_rootvp;
394 vref(*vpp);
395 vn_lock(*vpp, lktype);
396 MARK_INT_SAT(CODA_ROOT_STATS);
397 goto exit;
398 } else if (error == ENODEV || error == EINTR) {
399 /* Gross hack here! */
400 /*
401 * If Venus fails to respond to the CODA_ROOT call, coda_call returns
402 * ENODEV. Return the uninitialized root vnode to allow vfs
403 * operations such as unmount to continue. Without this hack,
404 * there is no way to do an unmount if Venus dies before a
405 * successful CODA_ROOT call is done. All vnode operations
406 * will fail.
407 */
408 *vpp = mi->mi_rootvp;
409 vref(*vpp);
410 vn_lock(*vpp, lktype);
411 MARK_INT_FAIL(CODA_ROOT_STATS);
412 error = 0;
413 goto exit;
414 } else {
415 CODADEBUG( CODA_ROOT, myprintf(("error %d in CODA_ROOT\n", error)); );
416 MARK_INT_FAIL(CODA_ROOT_STATS);
417
418 goto exit;
419 }
420 exit:
421 return(error);
422 }
423
424 /*
425 * Get file system statistics.
426 */
427 int
coda_nb_statvfs(struct mount * vfsp,struct statvfs * sbp)428 coda_nb_statvfs(struct mount *vfsp, struct statvfs *sbp)
429 {
430 struct lwp *l = curlwp;
431 struct coda_statfs fsstat;
432 int error;
433
434 ENTRY;
435 MARK_ENTRY(CODA_STATFS_STATS);
436 if (!CODA_MOUNTED(vfsp)) {
437 /* MARK_INT_FAIL(CODA_STATFS_STATS); */
438 return(EINVAL);
439 }
440
441 /* XXX - what to do about f_flags, others? --bnoble */
442 /* Below This is what AFS does
443 #define NB_SFS_SIZ 0x895440
444 */
445 /* Note: Normal fs's have a bsize of 0x400 == 1024 */
446
447 error = venus_statfs(vftomi(vfsp), l->l_cred, l, &fsstat);
448
449 if (!error) {
450 sbp->f_bsize = 8192; /* XXX */
451 sbp->f_frsize = 8192; /* XXX */
452 sbp->f_iosize = 8192; /* XXX */
453 sbp->f_blocks = fsstat.f_blocks;
454 sbp->f_bfree = fsstat.f_bfree;
455 sbp->f_bavail = fsstat.f_bavail;
456 sbp->f_bresvd = 0;
457 sbp->f_files = fsstat.f_files;
458 sbp->f_ffree = fsstat.f_ffree;
459 sbp->f_favail = fsstat.f_ffree;
460 sbp->f_fresvd = 0;
461 copy_statvfs_info(sbp, vfsp);
462 }
463
464 MARK_INT_SAT(CODA_STATFS_STATS);
465 return(error);
466 }
467
468 /*
469 * Flush any pending I/O.
470 */
471 int
coda_sync(struct mount * vfsp,int waitfor,kauth_cred_t cred)472 coda_sync(struct mount *vfsp, int waitfor,
473 kauth_cred_t cred)
474 {
475 ENTRY;
476 MARK_ENTRY(CODA_SYNC_STATS);
477 MARK_INT_SAT(CODA_SYNC_STATS);
478 return(0);
479 }
480
481 int
coda_vget(struct mount * vfsp,ino_t ino,int lktype,struct vnode ** vpp)482 coda_vget(struct mount *vfsp, ino_t ino, int lktype,
483 struct vnode **vpp)
484 {
485 ENTRY;
486 return (EOPNOTSUPP);
487 }
488
489 int
coda_loadvnode(struct mount * mp,struct vnode * vp,const void * key,size_t key_len,const void ** new_key)490 coda_loadvnode(struct mount *mp, struct vnode *vp,
491 const void *key, size_t key_len, const void **new_key)
492 {
493 CodaFid fid;
494 struct cnode *cp;
495 extern int (**coda_vnodeop_p)(void *);
496
497 KASSERT(key_len == sizeof(CodaFid));
498 memcpy(&fid, key, key_len);
499
500 cp = kmem_zalloc(sizeof(*cp), KM_SLEEP);
501 mutex_init(&cp->c_lock, MUTEX_DEFAULT, IPL_NONE);
502 cp->c_fid = fid;
503 cp->c_vnode = vp;
504 vp->v_op = coda_vnodeop_p;
505 vp->v_tag = VT_CODA;
506 vp->v_type = VNON;
507 vp->v_data = cp;
508
509 *new_key = &cp->c_fid;
510
511 return 0;
512 }
513
514 /*
515 * fhtovp is now what vget used to be in 4.3-derived systems. For
516 * some silly reason, vget is now keyed by a 32 bit ino_t, rather than
517 * a type-specific fid.
518 */
519 int
coda_fhtovp(struct mount * vfsp,struct fid * fhp,struct mbuf * nam,struct vnode ** vpp,int * exflagsp,kauth_cred_t * creadanonp,int lktype)520 coda_fhtovp(struct mount *vfsp, struct fid *fhp, struct mbuf *nam,
521 struct vnode **vpp, int *exflagsp,
522 kauth_cred_t *creadanonp, int lktype)
523 {
524 struct cfid *cfid = (struct cfid *)fhp;
525 struct cnode *cp = 0;
526 int error;
527 struct lwp *l = curlwp; /* XXX -mach */
528 CodaFid VFid;
529 int vtype;
530
531 ENTRY;
532
533 MARK_ENTRY(CODA_VGET_STATS);
534 /* Check for vget of control object. */
535 if (IS_CTL_FID(&cfid->cfid_fid)) {
536 *vpp = coda_ctlvp;
537 vref(coda_ctlvp);
538 MARK_INT_SAT(CODA_VGET_STATS);
539 return(0);
540 }
541
542 error = venus_fhtovp(vftomi(vfsp), &cfid->cfid_fid, l->l_cred, l->l_proc, &VFid, &vtype);
543
544 if (error) {
545 CODADEBUG(CODA_VGET, myprintf(("vget error %d\n",error));)
546 *vpp = (struct vnode *)0;
547 } else {
548 CODADEBUG(CODA_VGET,
549 myprintf(("vget: %s type %d result %d\n",
550 coda_f2s(&VFid), vtype, error)); )
551
552 cp = make_coda_node(&VFid, vfsp, vtype);
553 *vpp = CTOV(cp);
554 }
555 return(error);
556 }
557
558 int
coda_vptofh(struct vnode * vnp,struct fid * fidp)559 coda_vptofh(struct vnode *vnp, struct fid *fidp)
560 {
561 ENTRY;
562 return (EOPNOTSUPP);
563 }
564
565 void
coda_init(void)566 coda_init(void)
567 {
568 ENTRY;
569 }
570
571 void
coda_done(void)572 coda_done(void)
573 {
574 ENTRY;
575 }
576
577 SYSCTL_SETUP(sysctl_vfs_coda_setup, "sysctl vfs.coda subtree setup")
578 {
579
580 sysctl_createv(clog, 0, NULL, NULL,
581 CTLFLAG_PERMANENT,
582 CTLTYPE_NODE, "coda",
583 SYSCTL_DESCR("code vfs options"),
584 NULL, 0, NULL, 0,
585 CTL_VFS, 18, CTL_EOL);
586 /*
587 * XXX the "18" above could be dynamic, thereby eliminating
588 * one more instance of the "number to vfs" mapping problem,
589 * but "18" is the order as taken from sys/mount.h
590 */
591
592 /*
593 sysctl_createv(clog, 0, NULL, NULL,
594 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
595 CTLTYPE_INT, "clusterread",
596 SYSCTL_DESCR( anyone? ),
597 NULL, 0, &doclusterread, 0,
598 CTL_VFS, 18, FFS_CLUSTERREAD, CTL_EOL);
599 */
600 }
601
602 /*
603 * To allow for greater ease of use, some vnodes may be orphaned when
604 * Venus dies. Certain operations should still be allowed to go
605 * through, but without propagating orphan-ness. So this function will
606 * get a new vnode for the file from the current run of Venus.
607 */
608
609 int
getNewVnode(struct vnode ** vpp)610 getNewVnode(struct vnode **vpp)
611 {
612 struct cfid cfid;
613 struct coda_mntinfo *mi = vftomi((*vpp)->v_mount);
614
615 ENTRY;
616
617 cfid.cfid_len = (short)sizeof(CodaFid);
618 cfid.cfid_fid = VTOC(*vpp)->c_fid; /* Structure assignment. */
619 /* XXX ? */
620
621 /* We're guessing that if set, the 1st element on the list is a
622 * valid vnode to use. If not, return ENODEV as venus is dead.
623 */
624 if (mi->mi_vfsp == NULL)
625 return ENODEV;
626
627 return coda_fhtovp(mi->mi_vfsp, (struct fid*)&cfid, NULL, vpp,
628 NULL, NULL, LK_EXCLUSIVE);
629 }
630
631 /* Get the mount structure corresponding to a given device.
632 * Return NULL if no device is found or the device is not mounted.
633 */
devtomp(dev_t dev)634 struct mount *devtomp(dev_t dev)
635 {
636 struct mount *mp;
637 struct vnode *vp;
638
639 if (spec_node_lookup_by_dev(VBLK, dev, VDEAD_NOWAIT, &vp) == 0) {
640 mp = spec_node_getmountedfs(vp);
641 vrele(vp);
642 } else {
643 mp = NULL;
644 }
645
646 return mp;
647 }
648