vfs_default.c revision 189450 
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 189450 2009-03-06 15:35:37Z kib $");
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/lockf.h>
48#include <sys/malloc.h>
49#include <sys/mount.h>
50#include <sys/mutex.h>
51#include <sys/unistd.h>
52#include <sys/vnode.h>
53#include <sys/poll.h>
54
55#include <vm/vm.h>
56#include <vm/vm_object.h>
57#include <vm/vm_extern.h>
58#include <vm/pmap.h>
59#include <vm/vm_map.h>
60#include <vm/vm_page.h>
61#include <vm/vm_pager.h>
62#include <vm/vnode_pager.h>
63
64static int	vop_nolookup(struct vop_lookup_args *);
65static int	vop_nostrategy(struct vop_strategy_args *);
66
67/*
68 * This vnode table stores what we want to do if the filesystem doesn't
69 * implement a particular VOP.
70 *
71 * If there is no specific entry here, we will return EOPNOTSUPP.
72 *
73 */
74
75struct vop_vector default_vnodeops = {
76	.vop_default =		NULL,
77	.vop_bypass =		VOP_EOPNOTSUPP,
78
79	.vop_advlock =		vop_stdadvlock,
80	.vop_advlockasync =	vop_stdadvlockasync,
81	.vop_bmap =		vop_stdbmap,
82	.vop_close =		VOP_NULL,
83	.vop_fsync =		VOP_NULL,
84	.vop_getpages =		vop_stdgetpages,
85	.vop_getwritemount = 	vop_stdgetwritemount,
86	.vop_inactive =		VOP_NULL,
87	.vop_ioctl =		VOP_ENOTTY,
88	.vop_kqfilter =		vop_stdkqfilter,
89	.vop_islocked =		vop_stdislocked,
90	.vop_lease =		VOP_NULL,
91	.vop_lock1 =		vop_stdlock,
92	.vop_lookup =		vop_nolookup,
93	.vop_open =		VOP_NULL,
94	.vop_pathconf =		VOP_EINVAL,
95	.vop_poll =		vop_nopoll,
96	.vop_putpages =		vop_stdputpages,
97	.vop_readlink =		VOP_EINVAL,
98	.vop_revoke =		VOP_PANIC,
99	.vop_strategy =		vop_nostrategy,
100	.vop_unlock =		vop_stdunlock,
101	.vop_vptocnp =		VOP_ENOENT,
102	.vop_vptofh =		vop_stdvptofh,
103};
104
105/*
106 * Series of placeholder functions for various error returns for
107 * VOPs.
108 */
109
110int
111vop_eopnotsupp(struct vop_generic_args *ap)
112{
113	/*
114	printf("vop_notsupp[%s]\n", ap->a_desc->vdesc_name);
115	*/
116
117	return (EOPNOTSUPP);
118}
119
120int
121vop_ebadf(struct vop_generic_args *ap)
122{
123
124	return (EBADF);
125}
126
127int
128vop_enotty(struct vop_generic_args *ap)
129{
130
131	return (ENOTTY);
132}
133
134int
135vop_einval(struct vop_generic_args *ap)
136{
137
138	return (EINVAL);
139}
140
141int
142vop_enoent(struct vop_generic_args *ap)
143{
144
145	return (ENOENT);
146}
147
148int
149vop_null(struct vop_generic_args *ap)
150{
151
152	return (0);
153}
154
155/*
156 * Helper function to panic on some bad VOPs in some filesystems.
157 */
158int
159vop_panic(struct vop_generic_args *ap)
160{
161
162	panic("filesystem goof: vop_panic[%s]", ap->a_desc->vdesc_name);
163}
164
165/*
166 * vop_std<something> and vop_no<something> are default functions for use by
167 * filesystems that need the "default reasonable" implementation for a
168 * particular operation.
169 *
170 * The documentation for the operations they implement exists (if it exists)
171 * in the VOP_<SOMETHING>(9) manpage (all uppercase).
172 */
173
174/*
175 * Default vop for filesystems that do not support name lookup
176 */
177static int
178vop_nolookup(ap)
179	struct vop_lookup_args /* {
180		struct vnode *a_dvp;
181		struct vnode **a_vpp;
182		struct componentname *a_cnp;
183	} */ *ap;
184{
185
186	*ap->a_vpp = NULL;
187	return (ENOTDIR);
188}
189
190/*
191 *	vop_nostrategy:
192 *
193 *	Strategy routine for VFS devices that have none.
194 *
195 *	BIO_ERROR and B_INVAL must be cleared prior to calling any strategy
196 *	routine.  Typically this is done for a BIO_READ strategy call.
197 *	Typically B_INVAL is assumed to already be clear prior to a write
198 *	and should not be cleared manually unless you just made the buffer
199 *	invalid.  BIO_ERROR should be cleared either way.
200 */
201
202static int
203vop_nostrategy (struct vop_strategy_args *ap)
204{
205	printf("No strategy for buffer at %p\n", ap->a_bp);
206	vprint("vnode", ap->a_vp);
207	ap->a_bp->b_ioflags |= BIO_ERROR;
208	ap->a_bp->b_error = EOPNOTSUPP;
209	bufdone(ap->a_bp);
210	return (EOPNOTSUPP);
211}
212
213/*
214 * Advisory record locking support
215 */
216int
217vop_stdadvlock(struct vop_advlock_args *ap)
218{
219	struct vnode *vp;
220	struct ucred *cred;
221	struct vattr vattr;
222	int error;
223
224	vp = ap->a_vp;
225	cred = curthread->td_ucred;
226	vn_lock(vp, LK_SHARED | LK_RETRY);
227	error = VOP_GETATTR(vp, &vattr, cred);
228	VOP_UNLOCK(vp, 0);
229	if (error)
230		return (error);
231
232	return (lf_advlock(ap, &(vp->v_lockf), vattr.va_size));
233}
234
235int
236vop_stdadvlockasync(struct vop_advlockasync_args *ap)
237{
238	struct vnode *vp;
239	struct ucred *cred;
240	struct vattr vattr;
241	int error;
242
243	vp = ap->a_vp;
244	cred = curthread->td_ucred;
245	vn_lock(vp, LK_SHARED | LK_RETRY);
246	error = VOP_GETATTR(vp, &vattr, cred);
247	VOP_UNLOCK(vp, 0);
248	if (error)
249		return (error);
250
251	return (lf_advlockasync(ap, &(vp->v_lockf), vattr.va_size));
252}
253
254/*
255 * vop_stdpathconf:
256 *
257 * Standard implementation of POSIX pathconf, to get information about limits
258 * for a filesystem.
259 * Override per filesystem for the case where the filesystem has smaller
260 * limits.
261 */
262int
263vop_stdpathconf(ap)
264	struct vop_pathconf_args /* {
265	struct vnode *a_vp;
266	int a_name;
267	int *a_retval;
268	} */ *ap;
269{
270
271	switch (ap->a_name) {
272		case _PC_NAME_MAX:
273			*ap->a_retval = NAME_MAX;
274			return (0);
275		case _PC_PATH_MAX:
276			*ap->a_retval = PATH_MAX;
277			return (0);
278		case _PC_LINK_MAX:
279			*ap->a_retval = LINK_MAX;
280			return (0);
281		case _PC_MAX_CANON:
282			*ap->a_retval = MAX_CANON;
283			return (0);
284		case _PC_MAX_INPUT:
285			*ap->a_retval = MAX_INPUT;
286			return (0);
287		case _PC_PIPE_BUF:
288			*ap->a_retval = PIPE_BUF;
289			return (0);
290		case _PC_CHOWN_RESTRICTED:
291			*ap->a_retval = 1;
292			return (0);
293		case _PC_VDISABLE:
294			*ap->a_retval = _POSIX_VDISABLE;
295			return (0);
296		default:
297			return (EINVAL);
298	}
299	/* NOTREACHED */
300}
301
302/*
303 * Standard lock, unlock and islocked functions.
304 */
305int
306vop_stdlock(ap)
307	struct vop_lock1_args /* {
308		struct vnode *a_vp;
309		int a_flags;
310		char *file;
311		int line;
312	} */ *ap;
313{
314	struct vnode *vp = ap->a_vp;
315
316	return (_lockmgr_args(vp->v_vnlock, ap->a_flags, VI_MTX(vp),
317	    LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT, ap->a_file,
318	    ap->a_line));
319}
320
321/* See above. */
322int
323vop_stdunlock(ap)
324	struct vop_unlock_args /* {
325		struct vnode *a_vp;
326		int a_flags;
327	} */ *ap;
328{
329	struct vnode *vp = ap->a_vp;
330
331	return (lockmgr(vp->v_vnlock, ap->a_flags | LK_RELEASE, VI_MTX(vp)));
332}
333
334/* See above. */
335int
336vop_stdislocked(ap)
337	struct vop_islocked_args /* {
338		struct vnode *a_vp;
339	} */ *ap;
340{
341
342	return (lockstatus(ap->a_vp->v_vnlock));
343}
344
345/*
346 * Return true for select/poll.
347 */
348int
349vop_nopoll(ap)
350	struct vop_poll_args /* {
351		struct vnode *a_vp;
352		int  a_events;
353		struct ucred *a_cred;
354		struct thread *a_td;
355	} */ *ap;
356{
357
358	return (poll_no_poll(ap->a_events));
359}
360
361/*
362 * Implement poll for local filesystems that support it.
363 */
364int
365vop_stdpoll(ap)
366	struct vop_poll_args /* {
367		struct vnode *a_vp;
368		int  a_events;
369		struct ucred *a_cred;
370		struct thread *a_td;
371	} */ *ap;
372{
373	if (ap->a_events & ~POLLSTANDARD)
374		return (vn_pollrecord(ap->a_vp, ap->a_td, ap->a_events));
375	return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
376}
377
378/*
379 * Return our mount point, as we will take charge of the writes.
380 */
381int
382vop_stdgetwritemount(ap)
383	struct vop_getwritemount_args /* {
384		struct vnode *a_vp;
385		struct mount **a_mpp;
386	} */ *ap;
387{
388	struct mount *mp;
389
390	/*
391	 * XXX Since this is called unlocked we may be recycled while
392	 * attempting to ref the mount.  If this is the case or mountpoint
393	 * will be set to NULL.  We only have to prevent this call from
394	 * returning with a ref to an incorrect mountpoint.  It is not
395	 * harmful to return with a ref to our previous mountpoint.
396	 */
397	mp = ap->a_vp->v_mount;
398	if (mp != NULL) {
399		vfs_ref(mp);
400		if (mp != ap->a_vp->v_mount) {
401			vfs_rel(mp);
402			mp = NULL;
403		}
404	}
405	*(ap->a_mpp) = mp;
406	return (0);
407}
408
409/* XXX Needs good comment and VOP_BMAP(9) manpage */
410int
411vop_stdbmap(ap)
412	struct vop_bmap_args /* {
413		struct vnode *a_vp;
414		daddr_t  a_bn;
415		struct bufobj **a_bop;
416		daddr_t *a_bnp;
417		int *a_runp;
418		int *a_runb;
419	} */ *ap;
420{
421
422	if (ap->a_bop != NULL)
423		*ap->a_bop = &ap->a_vp->v_bufobj;
424	if (ap->a_bnp != NULL)
425		*ap->a_bnp = ap->a_bn * btodb(ap->a_vp->v_mount->mnt_stat.f_iosize);
426	if (ap->a_runp != NULL)
427		*ap->a_runp = 0;
428	if (ap->a_runb != NULL)
429		*ap->a_runb = 0;
430	return (0);
431}
432
433int
434vop_stdfsync(ap)
435	struct vop_fsync_args /* {
436		struct vnode *a_vp;
437		struct ucred *a_cred;
438		int a_waitfor;
439		struct thread *a_td;
440	} */ *ap;
441{
442	struct vnode *vp = ap->a_vp;
443	struct buf *bp;
444	struct bufobj *bo;
445	struct buf *nbp;
446	int error = 0;
447	int maxretry = 1000;     /* large, arbitrarily chosen */
448
449	bo = &vp->v_bufobj;
450	BO_LOCK(bo);
451loop1:
452	/*
453	 * MARK/SCAN initialization to avoid infinite loops.
454	 */
455        TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) {
456                bp->b_vflags &= ~BV_SCANNED;
457		bp->b_error = 0;
458	}
459
460	/*
461	 * Flush all dirty buffers associated with a vnode.
462	 */
463loop2:
464	TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
465		if ((bp->b_vflags & BV_SCANNED) != 0)
466			continue;
467		bp->b_vflags |= BV_SCANNED;
468		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL))
469			continue;
470		BO_UNLOCK(bo);
471		KASSERT(bp->b_bufobj == bo,
472		    ("bp %p wrong b_bufobj %p should be %p",
473		    bp, bp->b_bufobj, bo));
474		if ((bp->b_flags & B_DELWRI) == 0)
475			panic("fsync: not dirty");
476		if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) {
477			vfs_bio_awrite(bp);
478		} else {
479			bremfree(bp);
480			bawrite(bp);
481		}
482		BO_LOCK(bo);
483		goto loop2;
484	}
485
486	/*
487	 * If synchronous the caller expects us to completely resolve all
488	 * dirty buffers in the system.  Wait for in-progress I/O to
489	 * complete (which could include background bitmap writes), then
490	 * retry if dirty blocks still exist.
491	 */
492	if (ap->a_waitfor == MNT_WAIT) {
493		bufobj_wwait(bo, 0, 0);
494		if (bo->bo_dirty.bv_cnt > 0) {
495			/*
496			 * If we are unable to write any of these buffers
497			 * then we fail now rather than trying endlessly
498			 * to write them out.
499			 */
500			TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs)
501				if ((error = bp->b_error) == 0)
502					continue;
503			if (error == 0 && --maxretry >= 0)
504				goto loop1;
505			error = EAGAIN;
506		}
507	}
508	BO_UNLOCK(bo);
509	if (error == EAGAIN)
510		vprint("fsync: giving up on dirty", vp);
511
512	return (error);
513}
514
515/* XXX Needs good comment and more info in the manpage (VOP_GETPAGES(9)). */
516int
517vop_stdgetpages(ap)
518	struct vop_getpages_args /* {
519		struct vnode *a_vp;
520		vm_page_t *a_m;
521		int a_count;
522		int a_reqpage;
523		vm_ooffset_t a_offset;
524	} */ *ap;
525{
526
527	return vnode_pager_generic_getpages(ap->a_vp, ap->a_m,
528	    ap->a_count, ap->a_reqpage);
529}
530
531int
532vop_stdkqfilter(struct vop_kqfilter_args *ap)
533{
534	return vfs_kqfilter(ap);
535}
536
537/* XXX Needs good comment and more info in the manpage (VOP_PUTPAGES(9)). */
538int
539vop_stdputpages(ap)
540	struct vop_putpages_args /* {
541		struct vnode *a_vp;
542		vm_page_t *a_m;
543		int a_count;
544		int a_sync;
545		int *a_rtvals;
546		vm_ooffset_t a_offset;
547	} */ *ap;
548{
549
550	return vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
551	     ap->a_sync, ap->a_rtvals);
552}
553
554int
555vop_stdvptofh(struct vop_vptofh_args *ap)
556{
557	return (EOPNOTSUPP);
558}
559
560/*
561 * vfs default ops
562 * used to fill the vfs function table to get reasonable default return values.
563 */
564int
565vfs_stdroot (mp, flags, vpp, td)
566	struct mount *mp;
567	int flags;
568	struct vnode **vpp;
569	struct thread *td;
570{
571
572	return (EOPNOTSUPP);
573}
574
575int
576vfs_stdstatfs (mp, sbp, td)
577	struct mount *mp;
578	struct statfs *sbp;
579	struct thread *td;
580{
581
582	return (EOPNOTSUPP);
583}
584
585int
586vfs_stdquotactl (mp, cmds, uid, arg, td)
587	struct mount *mp;
588	int cmds;
589	uid_t uid;
590	void *arg;
591	struct thread *td;
592{
593
594	return (EOPNOTSUPP);
595}
596
597int
598vfs_stdsync(mp, waitfor, td)
599	struct mount *mp;
600	int waitfor;
601	struct thread *td;
602{
603	struct vnode *vp, *mvp;
604	int error, lockreq, allerror = 0;
605
606	lockreq = LK_EXCLUSIVE | LK_INTERLOCK;
607	if (waitfor != MNT_WAIT)
608		lockreq |= LK_NOWAIT;
609	/*
610	 * Force stale buffer cache information to be flushed.
611	 */
612	MNT_ILOCK(mp);
613loop:
614	MNT_VNODE_FOREACH(vp, mp, mvp) {
615		/* bv_cnt is an acceptable race here. */
616		if (vp->v_bufobj.bo_dirty.bv_cnt == 0)
617			continue;
618		VI_LOCK(vp);
619		MNT_IUNLOCK(mp);
620		if ((error = vget(vp, lockreq, td)) != 0) {
621			MNT_ILOCK(mp);
622			if (error == ENOENT) {
623				MNT_VNODE_FOREACH_ABORT_ILOCKED(mp, mvp);
624				goto loop;
625			}
626			continue;
627		}
628		error = VOP_FSYNC(vp, waitfor, td);
629		if (error)
630			allerror = error;
631
632		/* Do not turn this into vput.  td is not always curthread. */
633		VOP_UNLOCK(vp, 0);
634		vrele(vp);
635		MNT_ILOCK(mp);
636	}
637	MNT_IUNLOCK(mp);
638	return (allerror);
639}
640
641int
642vfs_stdnosync (mp, waitfor, td)
643	struct mount *mp;
644	int waitfor;
645	struct thread *td;
646{
647
648	return (0);
649}
650
651int
652vfs_stdvget (mp, ino, flags, vpp)
653	struct mount *mp;
654	ino_t ino;
655	int flags;
656	struct vnode **vpp;
657{
658
659	return (EOPNOTSUPP);
660}
661
662int
663vfs_stdfhtovp (mp, fhp, vpp)
664	struct mount *mp;
665	struct fid *fhp;
666	struct vnode **vpp;
667{
668
669	return (EOPNOTSUPP);
670}
671
672int
673vfs_stdinit (vfsp)
674	struct vfsconf *vfsp;
675{
676
677	return (0);
678}
679
680int
681vfs_stduninit (vfsp)
682	struct vfsconf *vfsp;
683{
684
685	return(0);
686}
687
688int
689vfs_stdextattrctl(mp, cmd, filename_vp, attrnamespace, attrname, td)
690	struct mount *mp;
691	int cmd;
692	struct vnode *filename_vp;
693	int attrnamespace;
694	const char *attrname;
695	struct thread *td;
696{
697
698	if (filename_vp != NULL)
699		VOP_UNLOCK(filename_vp, 0);
700	return (EOPNOTSUPP);
701}
702
703int
704vfs_stdsysctl(mp, op, req)
705	struct mount *mp;
706	fsctlop_t op;
707	struct sysctl_req *req;
708{
709
710	return (EOPNOTSUPP);
711}
712
713/* end of vfs default ops */
714