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 bool *mp_busy)
217 {
218 int prev_stops, rc;
219
220 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
221 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_quotactl)(mp, cmd, uid, arg,
222 mp_busy);
223 sigallowstop(prev_stops);
224 return (rc);
225 }
226
227 static int
228 vfs_statfs_sigdefer(struct mount *mp, struct statfs *sbp)
229 {
230 int prev_stops, rc;
231
232 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
233 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_statfs)(mp, sbp);
234 sigallowstop(prev_stops);
235 return (rc);
236 }
237
238 static int
239 vfs_sync_sigdefer(struct mount *mp, int waitfor)
240 {
241 int prev_stops, rc;
242
243 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
244 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_sync)(mp, waitfor);
245 sigallowstop(prev_stops);
246 return (rc);
247 }
248
249 static int
250 vfs_vget_sigdefer(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
251 {
252 int prev_stops, rc;
253
254 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
255 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_vget)(mp, ino, flags, vpp);
256 sigallowstop(prev_stops);
257 return (rc);
258 }
259
260 static int
261 vfs_fhtovp_sigdefer(struct mount *mp, struct fid *fidp, int flags,
262 struct vnode **vpp)
263 {
264 int prev_stops, rc;
265
266 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
267 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_fhtovp)(mp, fidp, flags, vpp);
268 sigallowstop(prev_stops);
269 return (rc);
270 }
271
272 static int
273 vfs_checkexp_sigdefer(struct mount *mp, struct sockaddr *nam, uint64_t *exflg,
274 struct ucred **credp, int *numsecflavors, int *secflavors)
275 {
276 int prev_stops, rc;
277
278 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
279 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_checkexp)(mp, nam, exflg, credp,
280 numsecflavors, secflavors);
281 sigallowstop(prev_stops);
282 return (rc);
283 }
284
285 static int
286 vfs_extattrctl_sigdefer(struct mount *mp, int cmd, struct vnode *filename_vp,
287 int attrnamespace, const char *attrname)
288 {
289 int prev_stops, rc;
290
291 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
292 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_extattrctl)(mp, cmd,
293 filename_vp, attrnamespace, attrname);
294 sigallowstop(prev_stops);
295 return (rc);
296 }
297
298 static int
299 vfs_sysctl_sigdefer(struct mount *mp, fsctlop_t op, struct sysctl_req *req)
300 {
301 int prev_stops, rc;
302
303 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
304 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_sysctl)(mp, op, req);
305 sigallowstop(prev_stops);
306 return (rc);
307 }
308
309 static void
310 vfs_susp_clean_sigdefer(struct mount *mp)
311 {
312 int prev_stops;
313
314 if (*mp->mnt_vfc->vfc_vfsops_sd->vfs_susp_clean == NULL)
315 return;
316 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
317 (*mp->mnt_vfc->vfc_vfsops_sd->vfs_susp_clean)(mp);
318 sigallowstop(prev_stops);
319 }
320
321 static void
322 vfs_reclaim_lowervp_sigdefer(struct mount *mp, struct vnode *vp)
323 {
324 int prev_stops;
325
326 if (*mp->mnt_vfc->vfc_vfsops_sd->vfs_reclaim_lowervp == NULL)
327 return;
328 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
329 (*mp->mnt_vfc->vfc_vfsops_sd->vfs_reclaim_lowervp)(mp, vp);
330 sigallowstop(prev_stops);
331 }
332
333 static void
334 vfs_unlink_lowervp_sigdefer(struct mount *mp, struct vnode *vp)
335 {
336 int prev_stops;
337
338 if (*mp->mnt_vfc->vfc_vfsops_sd->vfs_unlink_lowervp == NULL)
339 return;
340 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
341 (*(mp)->mnt_vfc->vfc_vfsops_sd->vfs_unlink_lowervp)(mp, vp);
342 sigallowstop(prev_stops);
343 }
344
345 static void
346 vfs_purge_sigdefer(struct mount *mp)
347 {
348 int prev_stops;
349
350 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
351 (*mp->mnt_vfc->vfc_vfsops_sd->vfs_purge)(mp);
352 sigallowstop(prev_stops);
353 }
354
355 static int
356 vfs_report_lockf_sigdefer(struct mount *mp, struct sbuf *sb)
357 {
358 int prev_stops, rc;
359
360 prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
361 rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_report_lockf)(mp, sb);
362 sigallowstop(prev_stops);
363 return (rc);
364 }
365
366 static struct vfsops vfsops_sigdefer = {
367 .vfs_mount = vfs_mount_sigdefer,
368 .vfs_unmount = vfs_unmount_sigdefer,
369 .vfs_root = vfs_root_sigdefer,
370 .vfs_cachedroot = vfs_cachedroot_sigdefer,
371 .vfs_quotactl = vfs_quotactl_sigdefer,
372 .vfs_statfs = vfs_statfs_sigdefer,
373 .vfs_sync = vfs_sync_sigdefer,
374 .vfs_vget = vfs_vget_sigdefer,
375 .vfs_fhtovp = vfs_fhtovp_sigdefer,
376 .vfs_checkexp = vfs_checkexp_sigdefer,
377 .vfs_extattrctl = vfs_extattrctl_sigdefer,
378 .vfs_sysctl = vfs_sysctl_sigdefer,
379 .vfs_susp_clean = vfs_susp_clean_sigdefer,
380 .vfs_reclaim_lowervp = vfs_reclaim_lowervp_sigdefer,
381 .vfs_unlink_lowervp = vfs_unlink_lowervp_sigdefer,
382 .vfs_purge = vfs_purge_sigdefer,
383 .vfs_report_lockf = vfs_report_lockf_sigdefer,
384 };
385
386 /* Register a new filesystem type in the global table */
387 static int
388 vfs_register(struct vfsconf *vfc)
389 {
390 struct sysctl_oid *oidp;
391 struct vfsops *vfsops;
392 static int once;
393 struct vfsconf *tvfc;
394 uint32_t hashval;
395 int secondpass;
396
397 if (!once) {
398 vattr_null(&va_null);
399 once = 1;
400 }
401
402 if (vfc->vfc_version != VFS_VERSION) {
403 printf("ERROR: filesystem %s, unsupported ABI version %x\n",
404 vfc->vfc_name, vfc->vfc_version);
405 return (EINVAL);
406 }
407 vfsconf_lock();
408 if (vfs_byname_locked(vfc->vfc_name) != NULL) {
409 vfsconf_unlock();
410 return (EEXIST);
411 }
412
413 if (vfs_typenumhash != 0) {
414 /*
415 * Calculate a hash on vfc_name to use for vfc_typenum. Unless
416 * all of 1<->255 are assigned, it is limited to 8bits since
417 * that is what ZFS uses from vfc_typenum and is also the
418 * preferred range for vfs_getnewfsid().
419 */
420 hashval = fnv_32_str(vfc->vfc_name, FNV1_32_INIT);
421 hashval &= 0xff;
422 secondpass = 0;
423 do {
424 /* Look for and fix any collision. */
425 TAILQ_FOREACH(tvfc, &vfsconf, vfc_list) {
426 if (hashval == tvfc->vfc_typenum) {
427 if (hashval == 255 && secondpass == 0) {
428 hashval = 1;
429 secondpass = 1;
430 } else
431 hashval++;
432 break;
433 }
434 }
435 } while (tvfc != NULL);
436 vfc->vfc_typenum = hashval;
437 if (vfc->vfc_typenum >= maxvfsconf)
438 maxvfsconf = vfc->vfc_typenum + 1;
439 } else
440 vfc->vfc_typenum = maxvfsconf++;
441 TAILQ_INSERT_TAIL(&vfsconf, vfc, vfc_list);
442
443 /*
444 * Initialise unused ``struct vfsops'' fields, to use
445 * the vfs_std*() functions. Note, we need the mount
446 * and unmount operations, at the least. The check
447 * for vfsops available is just a debugging aid.
448 */
449 KASSERT(vfc->vfc_vfsops != NULL,
450 ("Filesystem %s has no vfsops", vfc->vfc_name));
451 /*
452 * Check the mount and unmount operations.
453 */
454 vfsops = vfc->vfc_vfsops;
455 KASSERT(vfsops->vfs_mount != NULL,
456 ("Filesystem %s has no mount op", vfc->vfc_name));
457 KASSERT(vfsops->vfs_unmount != NULL,
458 ("Filesystem %s has no unmount op", vfc->vfc_name));
459
460 if (vfsops->vfs_root == NULL)
461 /* return file system's root vnode */
462 vfsops->vfs_root = vfs_stdroot;
463 if (vfsops->vfs_quotactl == NULL)
464 /* quota control */
465 vfsops->vfs_quotactl = vfs_stdquotactl;
466 if (vfsops->vfs_statfs == NULL)
467 /* return file system's status */
468 vfsops->vfs_statfs = vfs_stdstatfs;
469 if (vfsops->vfs_sync == NULL)
470 /*
471 * flush unwritten data (nosync)
472 * file systems can use vfs_stdsync
473 * explicitly by setting it in the
474 * vfsop vector.
475 */
476 vfsops->vfs_sync = vfs_stdnosync;
477 if (vfsops->vfs_vget == NULL)
478 /* convert an inode number to a vnode */
479 vfsops->vfs_vget = vfs_stdvget;
480 if (vfsops->vfs_fhtovp == NULL)
481 /* turn an NFS file handle into a vnode */
482 vfsops->vfs_fhtovp = vfs_stdfhtovp;
483 if (vfsops->vfs_checkexp == NULL)
484 /* check if file system is exported */
485 vfsops->vfs_checkexp = vfs_stdcheckexp;
486 if (vfsops->vfs_init == NULL)
487 /* file system specific initialisation */
488 vfsops->vfs_init = vfs_stdinit;
489 if (vfsops->vfs_uninit == NULL)
490 /* file system specific uninitialisation */
491 vfsops->vfs_uninit = vfs_stduninit;
492 if (vfsops->vfs_extattrctl == NULL)
493 /* extended attribute control */
494 vfsops->vfs_extattrctl = vfs_stdextattrctl;
495 if (vfsops->vfs_sysctl == NULL)
496 vfsops->vfs_sysctl = vfs_stdsysctl;
497 if (vfsops->vfs_report_lockf == NULL)
498 vfsops->vfs_report_lockf = vfs_report_lockf;
499
500 if ((vfc->vfc_flags & VFCF_SBDRY) != 0) {
501 vfc->vfc_vfsops_sd = vfc->vfc_vfsops;
502 vfc->vfc_vfsops = &vfsops_sigdefer;
503 }
504
505 if (vfc->vfc_flags & VFCF_JAIL)
506 prison_add_vfs(vfc);
507
508 /*
509 * Call init function for this VFS...
510 */
511 if ((vfc->vfc_flags & VFCF_SBDRY) != 0)
512 vfc->vfc_vfsops_sd->vfs_init(vfc);
513 else
514 vfc->vfc_vfsops->vfs_init(vfc);
515 vfsconf_unlock();
516
517 /*
518 * If this filesystem has a sysctl node under vfs
519 * (i.e. vfs.xxfs), then change the oid number of that node to
520 * match the filesystem's type number. This allows user code
521 * which uses the type number to read sysctl variables defined
522 * by the filesystem to continue working. Since the oids are
523 * in a sorted list, we need to make sure the order is
524 * preserved by re-registering the oid after modifying its
525 * number.
526 */
527 sysctl_wlock();
528 RB_FOREACH(oidp, sysctl_oid_list, SYSCTL_CHILDREN(&sysctl___vfs)) {
529 if (strcmp(oidp->oid_name, vfc->vfc_name) == 0) {
530 sysctl_unregister_oid(oidp);
531 oidp->oid_number = vfc->vfc_typenum;
532 sysctl_register_oid(oidp);
533 break;
534 }
535 }
536 sysctl_wunlock();
537
538 return (0);
539 }
540
541 /* Remove registration of a filesystem type */
542 static int
543 vfs_unregister(struct vfsconf *vfc)
544 {
545 struct vfsconf *vfsp;
546 int error, maxtypenum;
547
548 vfsconf_lock();
549 vfsp = vfs_byname_locked(vfc->vfc_name);
550 if (vfsp == NULL) {
551 vfsconf_unlock();
552 return (EINVAL);
553 }
554 if (vfsp->vfc_refcount != 0) {
555 vfsconf_unlock();
556 return (EBUSY);
557 }
558 error = 0;
559 if ((vfc->vfc_flags & VFCF_SBDRY) != 0) {
560 if (vfc->vfc_vfsops_sd->vfs_uninit != NULL)
561 error = vfc->vfc_vfsops_sd->vfs_uninit(vfsp);
562 } else {
563 if (vfc->vfc_vfsops->vfs_uninit != NULL)
564 error = vfc->vfc_vfsops->vfs_uninit(vfsp);
565 }
566 if (error != 0) {
567 vfsconf_unlock();
568 return (error);
569 }
570 TAILQ_REMOVE(&vfsconf, vfsp, vfc_list);
571 maxtypenum = VFS_GENERIC;
572 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list)
573 if (maxtypenum < vfsp->vfc_typenum)
574 maxtypenum = vfsp->vfc_typenum;
575 maxvfsconf = maxtypenum + 1;
576 vfsconf_unlock();
577 return (0);
578 }
579
580 /*
581 * Standard kernel module handling code for filesystem modules.
582 * Referenced from VFS_SET().
583 */
584 int
585 vfs_modevent(module_t mod, int type, void *data)
586 {
587 struct vfsconf *vfc;
588 int error = 0;
589
590 vfc = (struct vfsconf *)data;
591
592 switch (type) {
593 case MOD_LOAD:
594 if (vfc)
595 error = vfs_register(vfc);
596 break;
597
598 case MOD_UNLOAD:
599 if (vfc)
600 error = vfs_unregister(vfc);
601 break;
602 default:
603 error = EOPNOTSUPP;
604 break;
605 }
606 return (error);
607 }
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