vfs_default.c revision 164248 
1/*-
2 * Copyright (c) 1989, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed
6 * to Berkeley by John Heidemann of the UCLA Ficus project.
7 *
8 * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
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 * 4. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD: head/sys/kern/vfs_default.c 164248 2006-11-13 05:51:22Z kmacy $");
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/bio.h>
41#include <sys/buf.h>
42#include <sys/conf.h>
43#include <sys/event.h>
44#include <sys/kernel.h>
45#include <sys/limits.h>
46#include <sys/lock.h>
47#include <sys/malloc.h>
48#include <sys/mount.h>
49#include <sys/mutex.h>
50#include <sys/unistd.h>
51#include <sys/vnode.h>
52#include <sys/poll.h>
53
54#include <vm/vm.h>
55#include <vm/vm_object.h>
56#include <vm/vm_extern.h>
57#include <vm/pmap.h>
58#include <vm/vm_map.h>
59#include <vm/vm_page.h>
60#include <vm/vm_pager.h>
61#include <vm/vnode_pager.h>
62
63static int	vop_nolookup(struct vop_lookup_args *);
64static int	vop_nostrategy(struct vop_strategy_args *);
65
66/*
67 * This vnode table stores what we want to do if the filesystem doesn't
68 * implement a particular VOP.
69 *
70 * If there is no specific entry here, we will return EOPNOTSUPP.
71 *
72 */
73
74struct vop_vector default_vnodeops = {
75	.vop_default =		NULL,
76	.vop_bypass =		VOP_EOPNOTSUPP,
77
78	.vop_advlock =		VOP_EINVAL,
79	.vop_bmap =		vop_stdbmap,
80	.vop_close =		VOP_NULL,
81	.vop_fsync =		VOP_NULL,
82	.vop_getpages =		vop_stdgetpages,
83	.vop_getwritemount = 	vop_stdgetwritemount,
84	.vop_inactive =		VOP_NULL,
85	.vop_ioctl =		VOP_ENOTTY,
86	.vop_kqfilter =		vop_stdkqfilter,
87	.vop_islocked =		vop_stdislocked,
88	.vop_lease =		VOP_NULL,
89	._vop_lock =		vop_stdlock,
90	.vop_lookup =		vop_nolookup,
91	.vop_open =		VOP_NULL,
92	.vop_pathconf =		VOP_EINVAL,
93	.vop_poll =		vop_nopoll,
94	.vop_putpages =		vop_stdputpages,
95	.vop_readlink =		VOP_EINVAL,
96	.vop_revoke =		VOP_PANIC,
97	.vop_strategy =		vop_nostrategy,
98	.vop_unlock =		vop_stdunlock,
99};
100
101/*
102 * Series of placeholder functions for various error returns for
103 * VOPs.
104 */
105
106int
107vop_eopnotsupp(struct vop_generic_args *ap)
108{
109	/*
110	printf("vop_notsupp[%s]\n", ap->a_desc->vdesc_name);
111	*/
112
113	return (EOPNOTSUPP);
114}
115
116int
117vop_ebadf(struct vop_generic_args *ap)
118{
119
120	return (EBADF);
121}
122
123int
124vop_enotty(struct vop_generic_args *ap)
125{
126
127	return (ENOTTY);
128}
129
130int
131vop_einval(struct vop_generic_args *ap)
132{
133
134	return (EINVAL);
135}
136
137int
138vop_null(struct vop_generic_args *ap)
139{
140
141	return (0);
142}
143
144/*
145 * Helper function to panic on some bad VOPs in some filesystems.
146 */
147int
148vop_panic(struct vop_generic_args *ap)
149{
150
151	panic("filesystem goof: vop_panic[%s]", ap->a_desc->vdesc_name);
152}
153
154/*
155 * vop_std<something> and vop_no<something> are default functions for use by
156 * filesystems that need the "default reasonable" implementation for a
157 * particular operation.
158 *
159 * The documentation for the operations they implement exists (if it exists)
160 * in the VOP_<SOMETHING>(9) manpage (all uppercase).
161 */
162
163/*
164 * Default vop for filesystems that do not support name lookup
165 */
166static int
167vop_nolookup(ap)
168	struct vop_lookup_args /* {
169		struct vnode *a_dvp;
170		struct vnode **a_vpp;
171		struct componentname *a_cnp;
172	} */ *ap;
173{
174
175	*ap->a_vpp = NULL;
176	return (ENOTDIR);
177}
178
179/*
180 *	vop_nostrategy:
181 *
182 *	Strategy routine for VFS devices that have none.
183 *
184 *	BIO_ERROR and B_INVAL must be cleared prior to calling any strategy
185 *	routine.  Typically this is done for a BIO_READ strategy call.
186 *	Typically B_INVAL is assumed to already be clear prior to a write
187 *	and should not be cleared manually unless you just made the buffer
188 *	invalid.  BIO_ERROR should be cleared either way.
189 */
190
191static int
192vop_nostrategy (struct vop_strategy_args *ap)
193{
194	printf("No strategy for buffer at %p\n", ap->a_bp);
195	vprint("vnode", ap->a_vp);
196	ap->a_bp->b_ioflags |= BIO_ERROR;
197	ap->a_bp->b_error = EOPNOTSUPP;
198	bufdone(ap->a_bp);
199	return (EOPNOTSUPP);
200}
201
202/*
203 * vop_stdpathconf:
204 *
205 * Standard implementation of POSIX pathconf, to get information about limits
206 * for a filesystem.
207 * Override per filesystem for the case where the filesystem has smaller
208 * limits.
209 */
210int
211vop_stdpathconf(ap)
212	struct vop_pathconf_args /* {
213	struct vnode *a_vp;
214	int a_name;
215	int *a_retval;
216	} */ *ap;
217{
218
219	switch (ap->a_name) {
220		case _PC_NAME_MAX:
221			*ap->a_retval = NAME_MAX;
222			return (0);
223		case _PC_PATH_MAX:
224			*ap->a_retval = PATH_MAX;
225			return (0);
226		case _PC_LINK_MAX:
227			*ap->a_retval = LINK_MAX;
228			return (0);
229		case _PC_MAX_CANON:
230			*ap->a_retval = MAX_CANON;
231			return (0);
232		case _PC_MAX_INPUT:
233			*ap->a_retval = MAX_INPUT;
234			return (0);
235		case _PC_PIPE_BUF:
236			*ap->a_retval = PIPE_BUF;
237			return (0);
238		case _PC_CHOWN_RESTRICTED:
239			*ap->a_retval = 1;
240			return (0);
241		case _PC_VDISABLE:
242			*ap->a_retval = _POSIX_VDISABLE;
243			return (0);
244		default:
245			return (EINVAL);
246	}
247	/* NOTREACHED */
248}
249
250/*
251 * Standard lock, unlock and islocked functions.
252 */
253int
254vop_stdlock(ap)
255	struct _vop_lock_args /* {
256		struct vnode *a_vp;
257		int a_flags;
258		struct thread *a_td;
259		char *file;
260		int line;
261	} */ *ap;
262{
263	struct vnode *vp = ap->a_vp;
264
265	return (_lockmgr(vp->v_vnlock, ap->a_flags, VI_MTX(vp), ap->a_td, ap->a_file, ap->a_line));
266}
267
268/* See above. */
269int
270vop_stdunlock(ap)
271	struct vop_unlock_args /* {
272		struct vnode *a_vp;
273		int a_flags;
274		struct thread *a_td;
275	} */ *ap;
276{
277	struct vnode *vp = ap->a_vp;
278
279	return (lockmgr(vp->v_vnlock, ap->a_flags | LK_RELEASE, VI_MTX(vp),
280	    ap->a_td));
281}
282
283/* See above. */
284int
285vop_stdislocked(ap)
286	struct vop_islocked_args /* {
287		struct vnode *a_vp;
288		struct thread *a_td;
289	} */ *ap;
290{
291
292	return (lockstatus(ap->a_vp->v_vnlock, ap->a_td));
293}
294
295/*
296 * Return true for select/poll.
297 */
298int
299vop_nopoll(ap)
300	struct vop_poll_args /* {
301		struct vnode *a_vp;
302		int  a_events;
303		struct ucred *a_cred;
304		struct thread *a_td;
305	} */ *ap;
306{
307	/*
308	 * Return true for read/write.  If the user asked for something
309	 * special, return POLLNVAL, so that clients have a way of
310	 * determining reliably whether or not the extended
311	 * functionality is present without hard-coding knowledge
312	 * of specific filesystem implementations.
313	 * Stay in sync with kern_conf.c::no_poll().
314	 */
315	if (ap->a_events & ~POLLSTANDARD)
316		return (POLLNVAL);
317
318	return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
319}
320
321/*
322 * Implement poll for local filesystems that support it.
323 */
324int
325vop_stdpoll(ap)
326	struct vop_poll_args /* {
327		struct vnode *a_vp;
328		int  a_events;
329		struct ucred *a_cred;
330		struct thread *a_td;
331	} */ *ap;
332{
333	if (ap->a_events & ~POLLSTANDARD)
334		return (vn_pollrecord(ap->a_vp, ap->a_td, ap->a_events));
335	return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
336}
337
338/*
339 * Return our mount point, as we will take charge of the writes.
340 */
341int
342vop_stdgetwritemount(ap)
343	struct vop_getwritemount_args /* {
344		struct vnode *a_vp;
345		struct mount **a_mpp;
346	} */ *ap;
347{
348	struct mount *mp;
349
350	/*
351	 * XXX Since this is called unlocked we may be recycled while
352	 * attempting to ref the mount.  If this is the case or mountpoint
353	 * will be set to NULL.  We only have to prevent this call from
354	 * returning with a ref to an incorrect mountpoint.  It is not
355	 * harmful to return with a ref to our previous mountpoint.
356	 */
357	mp = ap->a_vp->v_mount;
358	if (mp != NULL) {
359		vfs_ref(mp);
360		if (mp != ap->a_vp->v_mount) {
361			vfs_rel(mp);
362			mp = NULL;
363		}
364	}
365	*(ap->a_mpp) = mp;
366	return (0);
367}
368
369/* XXX Needs good comment and VOP_BMAP(9) manpage */
370int
371vop_stdbmap(ap)
372	struct vop_bmap_args /* {
373		struct vnode *a_vp;
374		daddr_t  a_bn;
375		struct bufobj **a_bop;
376		daddr_t *a_bnp;
377		int *a_runp;
378		int *a_runb;
379	} */ *ap;
380{
381
382	if (ap->a_bop != NULL)
383		*ap->a_bop = &ap->a_vp->v_bufobj;
384	if (ap->a_bnp != NULL)
385		*ap->a_bnp = ap->a_bn * btodb(ap->a_vp->v_mount->mnt_stat.f_iosize);
386	if (ap->a_runp != NULL)
387		*ap->a_runp = 0;
388	if (ap->a_runb != NULL)
389		*ap->a_runb = 0;
390	return (0);
391}
392
393int
394vop_stdfsync(ap)
395	struct vop_fsync_args /* {
396		struct vnode *a_vp;
397		struct ucred *a_cred;
398		int a_waitfor;
399		struct thread *a_td;
400	} */ *ap;
401{
402	struct vnode *vp = ap->a_vp;
403	struct buf *bp;
404	struct bufobj *bo;
405	struct buf *nbp;
406	int error = 0;
407	int maxretry = 1000;     /* large, arbitrarily chosen */
408
409	VI_LOCK(vp);
410loop1:
411	/*
412	 * MARK/SCAN initialization to avoid infinite loops.
413	 */
414        TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd, b_bobufs) {
415                bp->b_vflags &= ~BV_SCANNED;
416		bp->b_error = 0;
417	}
418
419	/*
420	 * Flush all dirty buffers associated with a vnode.
421	 */
422loop2:
423	TAILQ_FOREACH_SAFE(bp, &vp->v_bufobj.bo_dirty.bv_hd, b_bobufs, nbp) {
424		if ((bp->b_vflags & BV_SCANNED) != 0)
425			continue;
426		bp->b_vflags |= BV_SCANNED;
427		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL))
428			continue;
429		VI_UNLOCK(vp);
430		KASSERT(bp->b_bufobj == &vp->v_bufobj,
431		    ("bp %p wrong b_bufobj %p should be %p",
432		    bp, bp->b_bufobj, &vp->v_bufobj));
433		if ((bp->b_flags & B_DELWRI) == 0)
434			panic("fsync: not dirty");
435		if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) {
436			vfs_bio_awrite(bp);
437		} else {
438			bremfree(bp);
439			bawrite(bp);
440		}
441		VI_LOCK(vp);
442		goto loop2;
443	}
444
445	/*
446	 * If synchronous the caller expects us to completely resolve all
447	 * dirty buffers in the system.  Wait for in-progress I/O to
448	 * complete (which could include background bitmap writes), then
449	 * retry if dirty blocks still exist.
450	 */
451	if (ap->a_waitfor == MNT_WAIT) {
452		bo = &vp->v_bufobj;
453		bufobj_wwait(bo, 0, 0);
454		if (bo->bo_dirty.bv_cnt > 0) {
455			/*
456			 * If we are unable to write any of these buffers
457			 * then we fail now rather than trying endlessly
458			 * to write them out.
459			 */
460			TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs)
461				if ((error = bp->b_error) == 0)
462					continue;
463			if (error == 0 && --maxretry >= 0)
464				goto loop1;
465			error = EAGAIN;
466		}
467	}
468	VI_UNLOCK(vp);
469	if (error == EAGAIN)
470		vprint("fsync: giving up on dirty", vp);
471
472	return (error);
473}
474
475/* XXX Needs good comment and more info in the manpage (VOP_GETPAGES(9)). */
476int
477vop_stdgetpages(ap)
478	struct vop_getpages_args /* {
479		struct vnode *a_vp;
480		vm_page_t *a_m;
481		int a_count;
482		int a_reqpage;
483		vm_ooffset_t a_offset;
484	} */ *ap;
485{
486
487	return vnode_pager_generic_getpages(ap->a_vp, ap->a_m,
488	    ap->a_count, ap->a_reqpage);
489}
490
491int
492vop_stdkqfilter(struct vop_kqfilter_args *ap)
493{
494	return vfs_kqfilter(ap);
495}
496
497/* XXX Needs good comment and more info in the manpage (VOP_PUTPAGES(9)). */
498int
499vop_stdputpages(ap)
500	struct vop_putpages_args /* {
501		struct vnode *a_vp;
502		vm_page_t *a_m;
503		int a_count;
504		int a_sync;
505		int *a_rtvals;
506		vm_ooffset_t a_offset;
507	} */ *ap;
508{
509
510	return vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
511	     ap->a_sync, ap->a_rtvals);
512}
513
514/*
515 * vfs default ops
516 * used to fill the vfs function table to get reasonable default return values.
517 */
518int
519vfs_stdroot (mp, flags, vpp, td)
520	struct mount *mp;
521	int flags;
522	struct vnode **vpp;
523	struct thread *td;
524{
525
526	return (EOPNOTSUPP);
527}
528
529int
530vfs_stdstatfs (mp, sbp, td)
531	struct mount *mp;
532	struct statfs *sbp;
533	struct thread *td;
534{
535
536	return (EOPNOTSUPP);
537}
538
539int
540vfs_stdvptofh (vp, fhp)
541	struct vnode *vp;
542	struct fid *fhp;
543{
544
545	return (EOPNOTSUPP);
546}
547
548int
549vfs_stdquotactl (mp, cmds, uid, arg, td)
550	struct mount *mp;
551	int cmds;
552	uid_t uid;
553	void *arg;
554	struct thread *td;
555{
556
557	return (EOPNOTSUPP);
558}
559
560int
561vfs_stdsync(mp, waitfor, td)
562	struct mount *mp;
563	int waitfor;
564	struct thread *td;
565{
566	struct vnode *vp, *mvp;
567	int error, lockreq, allerror = 0;
568
569	lockreq = LK_EXCLUSIVE | LK_INTERLOCK;
570	if (waitfor != MNT_WAIT)
571		lockreq |= LK_NOWAIT;
572	/*
573	 * Force stale buffer cache information to be flushed.
574	 */
575	MNT_ILOCK(mp);
576loop:
577	MNT_VNODE_FOREACH(vp, mp, mvp) {
578
579		VI_LOCK(vp);
580		if (vp->v_bufobj.bo_dirty.bv_cnt == 0) {
581			VI_UNLOCK(vp);
582			continue;
583		}
584		MNT_IUNLOCK(mp);
585
586		if ((error = vget(vp, lockreq, td)) != 0) {
587			MNT_ILOCK(mp);
588			if (error == ENOENT) {
589				MNT_VNODE_FOREACH_ABORT_ILOCKED(mp, mvp);
590				goto loop;
591			}
592			continue;
593		}
594		error = VOP_FSYNC(vp, waitfor, td);
595		if (error)
596			allerror = error;
597
598		/* Do not turn this into vput.  td is not always curthread. */
599		VOP_UNLOCK(vp, 0, td);
600		vrele(vp);
601		MNT_ILOCK(mp);
602	}
603	MNT_IUNLOCK(mp);
604	return (allerror);
605}
606
607int
608vfs_stdnosync (mp, waitfor, td)
609	struct mount *mp;
610	int waitfor;
611	struct thread *td;
612{
613
614	return (0);
615}
616
617int
618vfs_stdvget (mp, ino, flags, vpp)
619	struct mount *mp;
620	ino_t ino;
621	int flags;
622	struct vnode **vpp;
623{
624
625	return (EOPNOTSUPP);
626}
627
628int
629vfs_stdfhtovp (mp, fhp, vpp)
630	struct mount *mp;
631	struct fid *fhp;
632	struct vnode **vpp;
633{
634
635	return (EOPNOTSUPP);
636}
637
638int
639vfs_stdinit (vfsp)
640	struct vfsconf *vfsp;
641{
642
643	return (0);
644}
645
646int
647vfs_stduninit (vfsp)
648	struct vfsconf *vfsp;
649{
650
651	return(0);
652}
653
654int
655vfs_stdextattrctl(mp, cmd, filename_vp, attrnamespace, attrname, td)
656	struct mount *mp;
657	int cmd;
658	struct vnode *filename_vp;
659	int attrnamespace;
660	const char *attrname;
661	struct thread *td;
662{
663
664	if (filename_vp != NULL)
665		VOP_UNLOCK(filename_vp, 0, td);
666	return (EOPNOTSUPP);
667}
668
669int
670vfs_stdsysctl(mp, op, req)
671	struct mount *mp;
672	fsctlop_t op;
673	struct sysctl_req *req;
674{
675
676	return (EOPNOTSUPP);
677}
678
679/* end of vfs default ops */
680