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 int
354 vfs_report_lockf_sigdefer(struct mount *mp, struct sbuf *sb)
355 {
356 int prev_stops, rc;
357
358 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
359 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_report_lockf)(mp, sb);
360 sigallowstop(prev_stops);
361 return (rc);
362 }
363
364 static struct vfsops vfsops_sigdefer = {
365 .vfs_mount = vfs_mount_sigdefer,
366 .vfs_unmount = vfs_unmount_sigdefer,
367 .vfs_root = vfs_root_sigdefer,
368 .vfs_cachedroot = vfs_cachedroot_sigdefer,
369 .vfs_quotactl = vfs_quotactl_sigdefer,
370 .vfs_statfs = vfs_statfs_sigdefer,
371 .vfs_sync = vfs_sync_sigdefer,
372 .vfs_vget = vfs_vget_sigdefer,
373 .vfs_fhtovp = vfs_fhtovp_sigdefer,
374 .vfs_checkexp = vfs_checkexp_sigdefer,
375 .vfs_extattrctl = vfs_extattrctl_sigdefer,
376 .vfs_sysctl = vfs_sysctl_sigdefer,
377 .vfs_susp_clean = vfs_susp_clean_sigdefer,
378 .vfs_reclaim_lowervp = vfs_reclaim_lowervp_sigdefer,
379 .vfs_unlink_lowervp = vfs_unlink_lowervp_sigdefer,
380 .vfs_purge = vfs_purge_sigdefer,
381 .vfs_report_lockf = vfs_report_lockf_sigdefer,
382 };
383
384 /* Register a new filesystem type in the global table */
385 static int
386 vfs_register(struct vfsconf *vfc)
387 {
388 struct sysctl_oid *oidp;
389 struct vfsops *vfsops;
390 static int once;
391 struct vfsconf *tvfc;
392 uint32_t hashval;
393 int secondpass;
394
395 if (!once) {
396 vattr_null(&va_null);
397 once = 1;
398 }
399
400 if (vfc->vfc_version != VFS_VERSION) {
401 printf("ERROR: filesystem %s, unsupported ABI version %x\n",
402 vfc->vfc_name, vfc->vfc_version);
403 return (EINVAL);
404 }
405 vfsconf_lock();
406 if (vfs_byname_locked(vfc->vfc_name) != NULL) {
407 vfsconf_unlock();
408 return (EEXIST);
409 }
410
411 if (vfs_typenumhash != 0) {
412 /*
413 * Calculate a hash on vfc_name to use for vfc_typenum. Unless
414 * all of 1<->255 are assigned, it is limited to 8bits since
415 * that is what ZFS uses from vfc_typenum and is also the
416 * preferred range for vfs_getnewfsid().
417 */
418 hashval = fnv_32_str(vfc->vfc_name, FNV1_32_INIT);
419 hashval &= 0xff;
420 secondpass = 0;
421 do {
422 /* Look for and fix any collision. */
423 TAILQ_FOREACH(tvfc, &vfsconf, vfc_list) {
424 if (hashval == tvfc->vfc_typenum) {
425 if (hashval == 255 && secondpass == 0) {
426 hashval = 1;
427 secondpass = 1;
428 } else
429 hashval++;
430 break;
431 }
432 }
433 } while (tvfc != NULL);
434 vfc->vfc_typenum = hashval;
435 if (vfc->vfc_typenum >= maxvfsconf)
436 maxvfsconf = vfc->vfc_typenum + 1;
437 } else
438 vfc->vfc_typenum = maxvfsconf++;
439 TAILQ_INSERT_TAIL(&vfsconf, vfc, vfc_list);
440
441 /*
442 * Initialise unused ``struct vfsops'' fields, to use
443 * the vfs_std*() functions. Note, we need the mount
444 * and unmount operations, at the least. The check
445 * for vfsops available is just a debugging aid.
446 */
447 KASSERT(vfc->vfc_vfsops != NULL,
448 ("Filesystem %s has no vfsops", vfc->vfc_name));
449 /*
450 * Check the mount and unmount operations.
451 */
452 vfsops = vfc->vfc_vfsops;
453 KASSERT(vfsops->vfs_mount != NULL,
454 ("Filesystem %s has no mount op", vfc->vfc_name));
455 KASSERT(vfsops->vfs_unmount != NULL,
456 ("Filesystem %s has no unmount op", vfc->vfc_name));
457
458 if (vfsops->vfs_root == NULL)
459 /* return file system's root vnode */
460 vfsops->vfs_root = vfs_stdroot;
461 if (vfsops->vfs_quotactl == NULL)
462 /* quota control */
463 vfsops->vfs_quotactl = vfs_stdquotactl;
464 if (vfsops->vfs_statfs == NULL)
465 /* return file system's status */
466 vfsops->vfs_statfs = vfs_stdstatfs;
467 if (vfsops->vfs_sync == NULL)
468 /*
469 * flush unwritten data (nosync)
470 * file systems can use vfs_stdsync
471 * explicitly by setting it in the
472 * vfsop vector.
473 */
474 vfsops->vfs_sync = vfs_stdnosync;
475 if (vfsops->vfs_vget == NULL)
476 /* convert an inode number to a vnode */
477 vfsops->vfs_vget = vfs_stdvget;
478 if (vfsops->vfs_fhtovp == NULL)
479 /* turn an NFS file handle into a vnode */
480 vfsops->vfs_fhtovp = vfs_stdfhtovp;
481 if (vfsops->vfs_checkexp == NULL)
482 /* check if file system is exported */
483 vfsops->vfs_checkexp = vfs_stdcheckexp;
484 if (vfsops->vfs_init == NULL)
485 /* file system specific initialisation */
486 vfsops->vfs_init = vfs_stdinit;
487 if (vfsops->vfs_uninit == NULL)
488 /* file system specific uninitialisation */
489 vfsops->vfs_uninit = vfs_stduninit;
490 if (vfsops->vfs_extattrctl == NULL)
491 /* extended attribute control */
492 vfsops->vfs_extattrctl = vfs_stdextattrctl;
493 if (vfsops->vfs_sysctl == NULL)
494 vfsops->vfs_sysctl = vfs_stdsysctl;
495 if (vfsops->vfs_report_lockf == NULL)
496 vfsops->vfs_report_lockf = vfs_report_lockf;
497
498 if ((vfc->vfc_flags & VFCF_SBDRY) != 0) {
499 vfc->vfc_vfsops_sd = vfc->vfc_vfsops;
500 vfc->vfc_vfsops = &vfsops_sigdefer;
501 }
502
503 if (vfc->vfc_flags & VFCF_JAIL)
504 prison_add_vfs(vfc);
505
506 /*
507 * Call init function for this VFS...
508 */
509 if ((vfc->vfc_flags & VFCF_SBDRY) != 0)
510 vfc->vfc_vfsops_sd->vfs_init(vfc);
511 else
512 vfc->vfc_vfsops->vfs_init(vfc);
513 vfsconf_unlock();
514
515 /*
516 * If this filesystem has a sysctl node under vfs
517 * (i.e. vfs.xxfs), then change the oid number of that node to
518 * match the filesystem's type number. This allows user code
519 * which uses the type number to read sysctl variables defined
520 * by the filesystem to continue working. Since the oids are
521 * in a sorted list, we need to make sure the order is
522 * preserved by re-registering the oid after modifying its
523 * number.
524 */
525 sysctl_wlock();
526 SLIST_FOREACH(oidp, SYSCTL_CHILDREN(&sysctl___vfs), oid_link) {
527 if (strcmp(oidp->oid_name, vfc->vfc_name) == 0) {
528 sysctl_unregister_oid(oidp);
529 oidp->oid_number = vfc->vfc_typenum;
530 sysctl_register_oid(oidp);
531 break;
532 }
533 }
534 sysctl_wunlock();
535
536 return (0);
537 }
538
539 /* Remove registration of a filesystem type */
540 static int
541 vfs_unregister(struct vfsconf *vfc)
542 {
543 struct vfsconf *vfsp;
544 int error, maxtypenum;
545
546 vfsconf_lock();
547 vfsp = vfs_byname_locked(vfc->vfc_name);
548 if (vfsp == NULL) {
549 vfsconf_unlock();
550 return (EINVAL);
551 }
552 if (vfsp->vfc_refcount != 0) {
553 vfsconf_unlock();
554 return (EBUSY);
555 }
556 error = 0;
557 if ((vfc->vfc_flags & VFCF_SBDRY) != 0) {
558 if (vfc->vfc_vfsops_sd->vfs_uninit != NULL)
559 error = vfc->vfc_vfsops_sd->vfs_uninit(vfsp);
560 } else {
561 if (vfc->vfc_vfsops->vfs_uninit != NULL)
562 error = vfc->vfc_vfsops->vfs_uninit(vfsp);
563 }
564 if (error != 0) {
565 vfsconf_unlock();
566 return (error);
567 }
568 TAILQ_REMOVE(&vfsconf, vfsp, vfc_list);
569 maxtypenum = VFS_GENERIC;
570 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list)
571 if (maxtypenum < vfsp->vfc_typenum)
572 maxtypenum = vfsp->vfc_typenum;
573 maxvfsconf = maxtypenum + 1;
574 vfsconf_unlock();
575 return (0);
576 }
577
578 /*
579 * Standard kernel module handling code for filesystem modules.
580 * Referenced from VFS_SET().
581 */
582 int
583 vfs_modevent(module_t mod, int type, void *data)
584 {
585 struct vfsconf *vfc;
586 int error = 0;
587
588 vfc = (struct vfsconf *)data;
589
590 switch (type) {
591 case MOD_LOAD:
592 if (vfc)
593 error = vfs_register(vfc);
594 break;
595
596 case MOD_UNLOAD:
597 if (vfc)
598 error = vfs_unregister(vfc);
599 break;
600 default:
601 error = EOPNOTSUPP;
602 break;
603 }
604 return (error);
605 }
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