FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_init.c
1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed
8 * to Berkeley by John Heidemann of the UCLA Ficus project.
9 *
10 * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)vfs_init.c 8.3 (Berkeley) 1/4/94
37 */
38
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/fnv_hash.h>
45 #include <sys/jail.h>
46 #include <sys/kernel.h>
47 #include <sys/linker.h>
48 #include <sys/mount.h>
49 #include <sys/proc.h>
50 #include <sys/sx.h>
51 #include <sys/syscallsubr.h>
52 #include <sys/sysctl.h>
53 #include <sys/vnode.h>
54 #include <sys/malloc.h>
55
56 static int vfs_register(struct vfsconf *);
57 static int vfs_unregister(struct vfsconf *);
58
59 MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes");
60
61 /*
62 * The highest defined VFS number.
63 */
64 int maxvfsconf = VFS_GENERIC + 1;
65
66 /*
67 * Single-linked list of configured VFSes.
68 * New entries are added/deleted by vfs_register()/vfs_unregister()
69 */
70 struct vfsconfhead vfsconf = TAILQ_HEAD_INITIALIZER(vfsconf);
71 struct sx vfsconf_sx;
72 SX_SYSINIT(vfsconf, &vfsconf_sx, "vfsconf");
73
74 /*
75 * Loader.conf variable vfs.typenumhash enables setting vfc_typenum using a hash
76 * calculation on vfc_name, so that it doesn't change when file systems are
77 * loaded in a different order. This will avoid the NFS server file handles from
78 * changing for file systems that use vfc_typenum in their fsid.
79 */
80 static int vfs_typenumhash = 1;
81 SYSCTL_INT(_vfs, OID_AUTO, typenumhash, CTLFLAG_RDTUN, &vfs_typenumhash, 0,
82 "Set vfc_typenum using a hash calculation on vfc_name, so that it does not"
83 "change when file systems are loaded in a different order.");
84
85 /*
86 * A Zen vnode attribute structure.
87 *
88 * Initialized when the first filesystem registers by vfs_register().
89 */
90 struct vattr va_null;
91
92 /*
93 * vfs_init.c
94 *
95 * Allocate and fill in operations vectors.
96 *
97 * An undocumented feature of this approach to defining operations is that
98 * there can be multiple entries in vfs_opv_descs for the same operations
99 * vector. This allows third parties to extend the set of operations
100 * supported by another layer in a binary compatibile way. For example,
101 * assume that NFS needed to be modified to support Ficus. NFS has an entry
102 * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by
103 * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions)
104 * listing those new operations Ficus adds to NFS, all without modifying the
105 * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but
106 * that is a(whole)nother story.) This is a feature.
107 */
108
109 /*
110 * Routines having to do with the management of the vnode table.
111 */
112
113 static struct vfsconf *
114 vfs_byname_locked(const char *name)
115 {
116 struct vfsconf *vfsp;
117
118 sx_assert(&vfsconf_sx, SA_LOCKED);
119 if (!strcmp(name, "ffs"))
120 name = "ufs";
121 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
122 if (!strcmp(name, vfsp->vfc_name))
123 return (vfsp);
124 }
125 return (NULL);
126 }
127
128 struct vfsconf *
129 vfs_byname(const char *name)
130 {
131 struct vfsconf *vfsp;
132
133 vfsconf_slock();
134 vfsp = vfs_byname_locked(name);
135 vfsconf_sunlock();
136 return (vfsp);
137 }
138
139 struct vfsconf *
140 vfs_byname_kld(const char *fstype, struct thread *td, int *error)
141 {
142 struct vfsconf *vfsp;
143 int fileid, loaded;
144
145 vfsp = vfs_byname(fstype);
146 if (vfsp != NULL)
147 return (vfsp);
148
149 /* Try to load the respective module. */
150 *error = kern_kldload(td, fstype, &fileid);
151 loaded = (*error == 0);
152 if (*error == EEXIST)
153 *error = 0;
154 if (*error)
155 return (NULL);
156
157 /* Look up again to see if the VFS was loaded. */
158 vfsp = vfs_byname(fstype);
159 if (vfsp == NULL) {
160 if (loaded)
161 (void)kern_kldunload(td, fileid, LINKER_UNLOAD_FORCE);
162 *error = ENODEV;
163 return (NULL);
164 }
165 return (vfsp);
166 }
167
168 static int
169 vfs_mount_sigdefer(struct mount *mp)
170 {
171 int prev_stops, rc;
172
173 TSRAW(curthread, TS_ENTER, "VFS_MOUNT", mp->mnt_vfc->vfc_name);
174 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
175 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_mount)(mp);
176 sigallowstop(prev_stops);
177 TSRAW(curthread, TS_EXIT, "VFS_MOUNT", mp->mnt_vfc->vfc_name);
178 return (rc);
179 }
180
181 static int
182 vfs_unmount_sigdefer(struct mount *mp, int mntflags)
183 {
184 int prev_stops, rc;
185
186 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
187 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_unmount)(mp, mntflags);
188 sigallowstop(prev_stops);
189 return (rc);
190 }
191
192 static int
193 vfs_root_sigdefer(struct mount *mp, int flags, struct vnode **vpp)
194 {
195 int prev_stops, rc;
196
197 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
198 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_root)(mp, flags, vpp);
199 sigallowstop(prev_stops);
200 return (rc);
201 }
202
203 static int
204 vfs_cachedroot_sigdefer(struct mount *mp, int flags, struct vnode **vpp)
205 {
206 int prev_stops, rc;
207
208 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
209 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_cachedroot)(mp, flags, vpp);
210 sigallowstop(prev_stops);
211 return (rc);
212 }
213
214 static int
215 vfs_quotactl_sigdefer(struct mount *mp, int cmd, uid_t uid, void *arg)
216 {
217 int prev_stops, rc;
218
219 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
220 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_quotactl)(mp, cmd, uid, arg);
221 sigallowstop(prev_stops);
222 return (rc);
223 }
224
225 static int
226 vfs_statfs_sigdefer(struct mount *mp, struct statfs *sbp)
227 {
228 int prev_stops, rc;
229
230 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
231 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_statfs)(mp, sbp);
232 sigallowstop(prev_stops);
233 return (rc);
234 }
235
236 static int
237 vfs_sync_sigdefer(struct mount *mp, int waitfor)
238 {
239 int prev_stops, rc;
240
241 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
242 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_sync)(mp, waitfor);
243 sigallowstop(prev_stops);
244 return (rc);
245 }
246
247 static int
248 vfs_vget_sigdefer(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
249 {
250 int prev_stops, rc;
251
252 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
253 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_vget)(mp, ino, flags, vpp);
254 sigallowstop(prev_stops);
255 return (rc);
256 }
257
258 static int
259 vfs_fhtovp_sigdefer(struct mount *mp, struct fid *fidp, int flags,
260 struct vnode **vpp)
261 {
262 int prev_stops, rc;
263
264 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
265 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_fhtovp)(mp, fidp, flags, vpp);
266 sigallowstop(prev_stops);
267 return (rc);
268 }
269
270 static int
271 vfs_checkexp_sigdefer(struct mount *mp, struct sockaddr *nam, uint64_t *exflg,
272 struct ucred **credp, int *numsecflavors, int *secflavors)
273 {
274 int prev_stops, rc;
275
276 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
277 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_checkexp)(mp, nam, exflg, credp,
278 numsecflavors, secflavors);
279 sigallowstop(prev_stops);
280 return (rc);
281 }
282
283 static int
284 vfs_extattrctl_sigdefer(struct mount *mp, int cmd, struct vnode *filename_vp,
285 int attrnamespace, const char *attrname)
286 {
287 int prev_stops, rc;
288
289 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
290 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_extattrctl)(mp, cmd,
291 filename_vp, attrnamespace, attrname);
292 sigallowstop(prev_stops);
293 return (rc);
294 }
295
296 static int
297 vfs_sysctl_sigdefer(struct mount *mp, fsctlop_t op, struct sysctl_req *req)
298 {
299 int prev_stops, rc;
300
301 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
302 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_sysctl)(mp, op, req);
303 sigallowstop(prev_stops);
304 return (rc);
305 }
306
307 static void
308 vfs_susp_clean_sigdefer(struct mount *mp)
309 {
310 int prev_stops;
311
312 if (*mp->mnt_vfc->vfc_vfsops_sd->vfs_susp_clean == NULL)
313 return;
314 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
315 (*mp->mnt_vfc->vfc_vfsops_sd->vfs_susp_clean)(mp);
316 sigallowstop(prev_stops);
317 }
318
319 static void
320 vfs_reclaim_lowervp_sigdefer(struct mount *mp, struct vnode *vp)
321 {
322 int prev_stops;
323
324 if (*mp->mnt_vfc->vfc_vfsops_sd->vfs_reclaim_lowervp == NULL)
325 return;
326 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
327 (*mp->mnt_vfc->vfc_vfsops_sd->vfs_reclaim_lowervp)(mp, vp);
328 sigallowstop(prev_stops);
329 }
330
331 static void
332 vfs_unlink_lowervp_sigdefer(struct mount *mp, struct vnode *vp)
333 {
334 int prev_stops;
335
336 if (*mp->mnt_vfc->vfc_vfsops_sd->vfs_unlink_lowervp == NULL)
337 return;
338 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
339 (*(mp)->mnt_vfc->vfc_vfsops_sd->vfs_unlink_lowervp)(mp, vp);
340 sigallowstop(prev_stops);
341 }
342
343 static void
344 vfs_purge_sigdefer(struct mount *mp)
345 {
346 int prev_stops;
347
348 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
349 (*mp->mnt_vfc->vfc_vfsops_sd->vfs_purge)(mp);
350 sigallowstop(prev_stops);
351 }
352
353 static struct vfsops vfsops_sigdefer = {
354 .vfs_mount = vfs_mount_sigdefer,
355 .vfs_unmount = vfs_unmount_sigdefer,
356 .vfs_root = vfs_root_sigdefer,
357 .vfs_cachedroot = vfs_cachedroot_sigdefer,
358 .vfs_quotactl = vfs_quotactl_sigdefer,
359 .vfs_statfs = vfs_statfs_sigdefer,
360 .vfs_sync = vfs_sync_sigdefer,
361 .vfs_vget = vfs_vget_sigdefer,
362 .vfs_fhtovp = vfs_fhtovp_sigdefer,
363 .vfs_checkexp = vfs_checkexp_sigdefer,
364 .vfs_extattrctl = vfs_extattrctl_sigdefer,
365 .vfs_sysctl = vfs_sysctl_sigdefer,
366 .vfs_susp_clean = vfs_susp_clean_sigdefer,
367 .vfs_reclaim_lowervp = vfs_reclaim_lowervp_sigdefer,
368 .vfs_unlink_lowervp = vfs_unlink_lowervp_sigdefer,
369 .vfs_purge = vfs_purge_sigdefer,
370
371 };
372
373 /* Register a new filesystem type in the global table */
374 static int
375 vfs_register(struct vfsconf *vfc)
376 {
377 struct sysctl_oid *oidp;
378 struct vfsops *vfsops;
379 static int once;
380 struct vfsconf *tvfc;
381 uint32_t hashval;
382 int secondpass;
383
384 if (!once) {
385 vattr_null(&va_null);
386 once = 1;
387 }
388
389 if (vfc->vfc_version != VFS_VERSION) {
390 printf("ERROR: filesystem %s, unsupported ABI version %x\n",
391 vfc->vfc_name, vfc->vfc_version);
392 return (EINVAL);
393 }
394 vfsconf_lock();
395 if (vfs_byname_locked(vfc->vfc_name) != NULL) {
396 vfsconf_unlock();
397 return (EEXIST);
398 }
399
400 if (vfs_typenumhash != 0) {
401 /*
402 * Calculate a hash on vfc_name to use for vfc_typenum. Unless
403 * all of 1<->255 are assigned, it is limited to 8bits since
404 * that is what ZFS uses from vfc_typenum and is also the
405 * preferred range for vfs_getnewfsid().
406 */
407 hashval = fnv_32_str(vfc->vfc_name, FNV1_32_INIT);
408 hashval &= 0xff;
409 secondpass = 0;
410 do {
411 /* Look for and fix any collision. */
412 TAILQ_FOREACH(tvfc, &vfsconf, vfc_list) {
413 if (hashval == tvfc->vfc_typenum) {
414 if (hashval == 255 && secondpass == 0) {
415 hashval = 1;
416 secondpass = 1;
417 } else
418 hashval++;
419 break;
420 }
421 }
422 } while (tvfc != NULL);
423 vfc->vfc_typenum = hashval;
424 if (vfc->vfc_typenum >= maxvfsconf)
425 maxvfsconf = vfc->vfc_typenum + 1;
426 } else
427 vfc->vfc_typenum = maxvfsconf++;
428 TAILQ_INSERT_TAIL(&vfsconf, vfc, vfc_list);
429
430 /*
431 * Initialise unused ``struct vfsops'' fields, to use
432 * the vfs_std*() functions. Note, we need the mount
433 * and unmount operations, at the least. The check
434 * for vfsops available is just a debugging aid.
435 */
436 KASSERT(vfc->vfc_vfsops != NULL,
437 ("Filesystem %s has no vfsops", vfc->vfc_name));
438 /*
439 * Check the mount and unmount operations.
440 */
441 vfsops = vfc->vfc_vfsops;
442 KASSERT(vfsops->vfs_mount != NULL,
443 ("Filesystem %s has no mount op", vfc->vfc_name));
444 KASSERT(vfsops->vfs_unmount != NULL,
445 ("Filesystem %s has no unmount op", vfc->vfc_name));
446
447 if (vfsops->vfs_root == NULL)
448 /* return file system's root vnode */
449 vfsops->vfs_root = vfs_stdroot;
450 if (vfsops->vfs_quotactl == NULL)
451 /* quota control */
452 vfsops->vfs_quotactl = vfs_stdquotactl;
453 if (vfsops->vfs_statfs == NULL)
454 /* return file system's status */
455 vfsops->vfs_statfs = vfs_stdstatfs;
456 if (vfsops->vfs_sync == NULL)
457 /*
458 * flush unwritten data (nosync)
459 * file systems can use vfs_stdsync
460 * explicitly by setting it in the
461 * vfsop vector.
462 */
463 vfsops->vfs_sync = vfs_stdnosync;
464 if (vfsops->vfs_vget == NULL)
465 /* convert an inode number to a vnode */
466 vfsops->vfs_vget = vfs_stdvget;
467 if (vfsops->vfs_fhtovp == NULL)
468 /* turn an NFS file handle into a vnode */
469 vfsops->vfs_fhtovp = vfs_stdfhtovp;
470 if (vfsops->vfs_checkexp == NULL)
471 /* check if file system is exported */
472 vfsops->vfs_checkexp = vfs_stdcheckexp;
473 if (vfsops->vfs_init == NULL)
474 /* file system specific initialisation */
475 vfsops->vfs_init = vfs_stdinit;
476 if (vfsops->vfs_uninit == NULL)
477 /* file system specific uninitialisation */
478 vfsops->vfs_uninit = vfs_stduninit;
479 if (vfsops->vfs_extattrctl == NULL)
480 /* extended attribute control */
481 vfsops->vfs_extattrctl = vfs_stdextattrctl;
482 if (vfsops->vfs_sysctl == NULL)
483 vfsops->vfs_sysctl = vfs_stdsysctl;
484
485 if ((vfc->vfc_flags & VFCF_SBDRY) != 0) {
486 vfc->vfc_vfsops_sd = vfc->vfc_vfsops;
487 vfc->vfc_vfsops = &vfsops_sigdefer;
488 }
489
490 if (vfc->vfc_flags & VFCF_JAIL)
491 prison_add_vfs(vfc);
492
493 /*
494 * Call init function for this VFS...
495 */
496 if ((vfc->vfc_flags & VFCF_SBDRY) != 0)
497 vfc->vfc_vfsops_sd->vfs_init(vfc);
498 else
499 vfc->vfc_vfsops->vfs_init(vfc);
500 vfsconf_unlock();
501
502 /*
503 * If this filesystem has a sysctl node under vfs
504 * (i.e. vfs.xxfs), then change the oid number of that node to
505 * match the filesystem's type number. This allows user code
506 * which uses the type number to read sysctl variables defined
507 * by the filesystem to continue working. Since the oids are
508 * in a sorted list, we need to make sure the order is
509 * preserved by re-registering the oid after modifying its
510 * number.
511 */
512 sysctl_wlock();
513 SLIST_FOREACH(oidp, SYSCTL_CHILDREN(&sysctl___vfs), oid_link) {
514 if (strcmp(oidp->oid_name, vfc->vfc_name) == 0) {
515 sysctl_unregister_oid(oidp);
516 oidp->oid_number = vfc->vfc_typenum;
517 sysctl_register_oid(oidp);
518 break;
519 }
520 }
521 sysctl_wunlock();
522
523 return (0);
524 }
525
526 /* Remove registration of a filesystem type */
527 static int
528 vfs_unregister(struct vfsconf *vfc)
529 {
530 struct vfsconf *vfsp;
531 int error, maxtypenum;
532
533 vfsconf_lock();
534 vfsp = vfs_byname_locked(vfc->vfc_name);
535 if (vfsp == NULL) {
536 vfsconf_unlock();
537 return (EINVAL);
538 }
539 if (vfsp->vfc_refcount != 0) {
540 vfsconf_unlock();
541 return (EBUSY);
542 }
543 error = 0;
544 if ((vfc->vfc_flags & VFCF_SBDRY) != 0) {
545 if (vfc->vfc_vfsops_sd->vfs_uninit != NULL)
546 error = vfc->vfc_vfsops_sd->vfs_uninit(vfsp);
547 } else {
548 if (vfc->vfc_vfsops->vfs_uninit != NULL) {
549 error = vfc->vfc_vfsops->vfs_uninit(vfsp);
550 }
551 if (error != 0) {
552 vfsconf_unlock();
553 return (error);
554 }
555 }
556 TAILQ_REMOVE(&vfsconf, vfsp, vfc_list);
557 maxtypenum = VFS_GENERIC;
558 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list)
559 if (maxtypenum < vfsp->vfc_typenum)
560 maxtypenum = vfsp->vfc_typenum;
561 maxvfsconf = maxtypenum + 1;
562 vfsconf_unlock();
563 return (0);
564 }
565
566 /*
567 * Standard kernel module handling code for filesystem modules.
568 * Referenced from VFS_SET().
569 */
570 int
571 vfs_modevent(module_t mod, int type, void *data)
572 {
573 struct vfsconf *vfc;
574 int error = 0;
575
576 vfc = (struct vfsconf *)data;
577
578 switch (type) {
579 case MOD_LOAD:
580 if (vfc)
581 error = vfs_register(vfc);
582 break;
583
584 case MOD_UNLOAD:
585 if (vfc)
586 error = vfs_unregister(vfc);
587 break;
588 default:
589 error = EOPNOTSUPP;
590 break;
591 }
592 return (error);
593 }
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