summaryrefslogtreecommitdiffstats
path: root/sys/fs/specfs/spec_vnops.c
blob: dce82120cb4bb7179d4d1ae0924c9db9c96a271a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
/*
 * Copyright (c) 1989, 1993, 1995
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)spec_vnops.c	8.14 (Berkeley) 5/21/95
 * $FreeBSD$
 */

#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/stat.h>
#include <sys/fcntl.h>
#include <sys/vmmeter.h>
#include <sys/tty.h>

#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>

static int	spec_advlock __P((struct vop_advlock_args *));  
static int	spec_bmap __P((struct vop_bmap_args *));
static int	spec_close __P((struct vop_close_args *));
static int	spec_freeblks __P((struct vop_freeblks_args *));
static int	spec_fsync __P((struct  vop_fsync_args *));
static int	spec_getpages __P((struct vop_getpages_args *));
static int	spec_ioctl __P((struct vop_ioctl_args *));
static int	spec_open __P((struct vop_open_args *));
static int	spec_poll __P((struct vop_poll_args *));
static int	spec_print __P((struct vop_print_args *));
static int	spec_read __P((struct vop_read_args *));  
static int	spec_strategy __P((struct vop_strategy_args *));
static int	spec_write __P((struct vop_write_args *));

vop_t **spec_vnodeop_p;
static struct vnodeopv_entry_desc spec_vnodeop_entries[] = {
	{ &vop_default_desc,		(vop_t *) vop_defaultop },
	{ &vop_access_desc,		(vop_t *) vop_ebadf },
	{ &vop_advlock_desc,		(vop_t *) spec_advlock },
	{ &vop_bmap_desc,		(vop_t *) spec_bmap },
	{ &vop_close_desc,		(vop_t *) spec_close },
	{ &vop_create_desc,		(vop_t *) vop_panic },
	{ &vop_freeblks_desc,		(vop_t *) spec_freeblks },
	{ &vop_fsync_desc,		(vop_t *) spec_fsync },
	{ &vop_getpages_desc,		(vop_t *) spec_getpages },
	{ &vop_getwritemount_desc, 	(vop_t *) vop_stdgetwritemount },
	{ &vop_ioctl_desc,		(vop_t *) spec_ioctl },
	{ &vop_lease_desc,		(vop_t *) vop_null },
	{ &vop_link_desc,		(vop_t *) vop_panic },
	{ &vop_mkdir_desc,		(vop_t *) vop_panic },
	{ &vop_mknod_desc,		(vop_t *) vop_panic },
	{ &vop_open_desc,		(vop_t *) spec_open },
	{ &vop_pathconf_desc,		(vop_t *) vop_stdpathconf },
	{ &vop_poll_desc,		(vop_t *) spec_poll },
	{ &vop_print_desc,		(vop_t *) spec_print },
	{ &vop_read_desc,		(vop_t *) spec_read },
	{ &vop_readdir_desc,		(vop_t *) vop_panic },
	{ &vop_readlink_desc,		(vop_t *) vop_panic },
	{ &vop_reallocblks_desc,	(vop_t *) vop_panic },
	{ &vop_reclaim_desc,		(vop_t *) vop_null },
	{ &vop_remove_desc,		(vop_t *) vop_panic },
	{ &vop_rename_desc,		(vop_t *) vop_panic },
	{ &vop_rmdir_desc,		(vop_t *) vop_panic },
	{ &vop_setattr_desc,		(vop_t *) vop_ebadf },
	{ &vop_strategy_desc,		(vop_t *) spec_strategy },
	{ &vop_symlink_desc,		(vop_t *) vop_panic },
	{ &vop_write_desc,		(vop_t *) spec_write },
	{ NULL, NULL }
};
static struct vnodeopv_desc spec_vnodeop_opv_desc =
	{ &spec_vnodeop_p, spec_vnodeop_entries };

VNODEOP_SET(spec_vnodeop_opv_desc);

int
spec_vnoperate(ap)
	struct vop_generic_args /* {
		struct vnodeop_desc *a_desc;
		<other random data follows, presumably>
	} */ *ap;
{
	return (VOCALL(spec_vnodeop_p, ap->a_desc->vdesc_offset, ap));
}

static void spec_getpages_iodone __P((struct buf *bp));

/*
 * Open a special file.
 */
/* ARGSUSED */
static int
spec_open(ap)
	struct vop_open_args /* {
		struct vnode *a_vp;
		int  a_mode;
		struct ucred *a_cred;
		struct proc *a_p;
	} */ *ap;
{
	struct proc *p = ap->a_p;
	struct vnode *vp = ap->a_vp;
	dev_t dev = vp->v_rdev;
	int error;
	struct cdevsw *dsw;
	const char *cp;

	if (vp->v_type == VBLK) 
		return ENXIO;
	/*
	 * Don't allow open if fs is mounted -nodev.
	 */
	if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_NODEV))
		return (ENXIO);

	dsw = devsw(dev);
	if ( (dsw == NULL) || (dsw->d_open == NULL))
		return ENXIO;

	/* Make this field valid before any I/O in ->d_open */
	if (!dev->si_iosize_max)
		dev->si_iosize_max = DFLTPHYS;

	/*
	 * XXX: Disks get special billing here, but it is mostly wrong.
	 * XXX: diskpartitions can overlap and the real checks should
	 * XXX: take this into account, and consequently they need to
	 * XXX: live in the diskslicing code.  Some checks do.
	 */
	if (vn_isdisk(vp, NULL) && ap->a_cred != FSCRED && 
	    (ap->a_mode & FWRITE)) {
		/*
		 * Never allow opens for write if the device is mounted R/W
		 */
		if (vp->v_rdev->si_mountpoint != NULL &&
		    !(vp->v_rdev->si_mountpoint->mnt_flag & MNT_RDONLY))
				return (EBUSY);

		/*
		 * When running in secure mode, do not allow opens
		 * for writing if the device is mounted
		 */
		if (securelevel >= 1 && vfs_mountedon(vp))
			return (EPERM);

		/*
		 * When running in very secure mode, do not allow
		 * opens for writing of any devices.
		 */
		if (securelevel >= 2)
			return (EPERM);
	}

	/* XXX: Special casing of ttys for deadfs.  Probably redundant */
	if (dsw->d_flags & D_TTY)
		vp->v_flag |= VISTTY;

	VOP_UNLOCK(vp, 0, p);
	error = (*dsw->d_open)(dev, ap->a_mode, S_IFCHR, p);
	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);

	if (error)
		return (error);

	if (dsw->d_flags & D_TTY) {
		if (dev->si_tty) {
			struct tty *tp;
			tp = dev->si_tty;
			if (!tp->t_stop) {
				printf("Warning:%s: no t_stop, using nottystop\n", devtoname(dev));
				tp->t_stop = nottystop;
			}
		}
	}

	if (vn_isdisk(vp, NULL)) {
		if (!dev->si_bsize_phys)
			dev->si_bsize_phys = DEV_BSIZE;
	}
	if ((dsw->d_flags & D_DISK) == 0) {
		cp = devtoname(dev);
		if (*cp == '#' && (dsw->d_flags & D_NAGGED) == 0) {
			printf("WARNING: driver %s should register devices with make_dev() (dev_t = \"%s\")\n",
			    dsw->d_name, cp);
			dsw->d_flags |= D_NAGGED;	
		}
	}
	return (error);
}

/*
 * Vnode op for read
 */
/* ARGSUSED */
static int
spec_read(ap)
	struct vop_read_args /* {
		struct vnode *a_vp;
		struct uio *a_uio;
		int a_ioflag;
		struct ucred *a_cred;
	} */ *ap;
{
	struct vnode *vp;
	struct proc *p;
	struct uio *uio;
	dev_t dev;
	int error, resid;

	vp = ap->a_vp;
	dev = vp->v_rdev;
	uio = ap->a_uio;
	p = uio->uio_procp;
	resid = uio->uio_resid;

	if (resid == 0)
		return (0);

	VOP_UNLOCK(vp, 0, p);
	error = (*devsw(dev)->d_read) (dev, uio, ap->a_ioflag);
	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
	if (uio->uio_resid != resid || (error == 0 && resid != 0))
		getnanotime(&dev->si_atime);
	return (error);
}

/*
 * Vnode op for write
 */
/* ARGSUSED */
static int
spec_write(ap)
	struct vop_write_args /* {
		struct vnode *a_vp;
		struct uio *a_uio;
		int a_ioflag;
		struct ucred *a_cred;
	} */ *ap;
{
	struct vnode *vp;
	struct proc *p;
	struct uio *uio;
	dev_t dev;
	int error, resid;

	vp = ap->a_vp;
	dev = vp->v_rdev;
	uio = ap->a_uio;
	p = uio->uio_procp;
	resid = uio->uio_resid;

	VOP_UNLOCK(vp, 0, p);
	error = (*devsw(dev)->d_write) (dev, uio, ap->a_ioflag);
	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
	if (uio->uio_resid != resid || (error == 0 && resid != 0)) {
		getnanotime(&dev->si_ctime);
		dev->si_mtime = dev->si_ctime;
	}
	return (error);
}

/*
 * Device ioctl operation.
 */
/* ARGSUSED */
static int
spec_ioctl(ap)
	struct vop_ioctl_args /* {
		struct vnode *a_vp;
		int  a_command;
		caddr_t  a_data;
		int  a_fflag;
		struct ucred *a_cred;
		struct proc *a_p;
	} */ *ap;
{
	dev_t dev;

	dev = ap->a_vp->v_rdev;
	return ((*devsw(dev)->d_ioctl)(dev, ap->a_command, 
	    ap->a_data, ap->a_fflag, ap->a_p));
}

/* ARGSUSED */
static int
spec_poll(ap)
	struct vop_poll_args /* {
		struct vnode *a_vp;
		int  a_events;
		struct ucred *a_cred;
		struct proc *a_p;
	} */ *ap;
{
	dev_t dev;

	dev = ap->a_vp->v_rdev;
	return (*devsw(dev)->d_poll)(dev, ap->a_events, ap->a_p);
}
/*
 * Synch buffers associated with a block device
 */
/* ARGSUSED */
static int
spec_fsync(ap)
	struct vop_fsync_args /* {
		struct vnode *a_vp;
		struct ucred *a_cred;
		int  a_waitfor;
		struct proc *a_p;
	} */ *ap;
{
	struct vnode *vp = ap->a_vp;
	struct buf *bp;
	struct buf *nbp;
	int s;
	int maxretry = 10000;	/* large, arbitrarily chosen */

	if (!vn_isdisk(vp, NULL))
		return (0);

loop1:
	/*
	 * MARK/SCAN initialization to avoid infinite loops
	 */
	s = splbio();
        TAILQ_FOREACH(bp, &vp->v_dirtyblkhd, b_vnbufs) {
                bp->b_flags &= ~B_SCANNED;
	}
	splx(s);

	/*
	 * Flush all dirty buffers associated with a block device.
	 */
loop2:
	s = splbio();
	for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
		nbp = TAILQ_NEXT(bp, b_vnbufs);
		if ((bp->b_flags & B_SCANNED) != 0)
			continue;
		bp->b_flags |= B_SCANNED;
		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT))
			continue;
		if ((bp->b_flags & B_DELWRI) == 0)
			panic("spec_fsync: not dirty");
		if ((vp->v_flag & VOBJBUF) && (bp->b_flags & B_CLUSTEROK)) {
			BUF_UNLOCK(bp);
			vfs_bio_awrite(bp);
			splx(s);
		} else {
			bremfree(bp);
			splx(s);
			bawrite(bp);
		}
		goto loop2;
	}

	/*
	 * If synchronous the caller expects us to completely resolve all
	 * dirty buffers in the system.  Wait for in-progress I/O to
	 * complete (which could include background bitmap writes), then
	 * retry if dirty blocks still exist.
	 */
	if (ap->a_waitfor == MNT_WAIT) {
		while (vp->v_numoutput) {
			vp->v_flag |= VBWAIT;
			(void) tsleep((caddr_t)&vp->v_numoutput, PRIBIO + 1, "spfsyn", 0);
		}
		if (!TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
			if (--maxretry != 0) {
				splx(s);
				goto loop1;
			}
			vprint("spec_fsync: giving up on dirty", vp);
		}
	}
	splx(s);
	return (0);
}

/*
 * Just call the device strategy routine
 */
static int
spec_strategy(ap)
	struct vop_strategy_args /* {
		struct vnode *a_vp;
		struct buf *a_bp;
	} */ *ap;
{
	struct buf *bp;
	struct vnode *vp;
	struct mount *mp;
	int error;

	bp = ap->a_bp;
	vp = ap->a_vp;
	if ((bp->b_iocmd == BIO_WRITE)) {
		if ((bp->b_flags & B_VALIDSUSPWRT) == 0 &&
		    bp->b_vp != NULL && bp->b_vp->v_mount != NULL &&
		    (bp->b_vp->v_mount->mnt_kern_flag & MNTK_SUSPENDED) != 0)
			panic("spec_strategy: bad I/O");
		bp->b_flags &= ~B_VALIDSUSPWRT;
		if (LIST_FIRST(&bp->b_dep) != NULL)
			buf_start(bp);
		if ((vp->v_flag & VCOPYONWRITE) &&
		    (error = VOP_COPYONWRITE(vp, bp)) != 0 &&
		    error != EOPNOTSUPP) {
			bp->b_io.bio_error = error;
			bp->b_io.bio_flags |= BIO_ERROR;
			biodone(&bp->b_io);
			return (0);
		}
	}
	/*
	 * Collect statistics on synchronous and asynchronous read
	 * and write counts for disks that have associated filesystems.
	 */
	if (vn_isdisk(vp, NULL) && (mp = vp->v_rdev->si_mountpoint) != NULL) {
		if (bp->b_iocmd == BIO_WRITE) {
			if (bp->b_lock.lk_lockholder == LK_KERNPROC)
				mp->mnt_stat.f_asyncwrites++;
			else
				mp->mnt_stat.f_syncwrites++;
		} else {
			if (bp->b_lock.lk_lockholder == LK_KERNPROC)
				mp->mnt_stat.f_asyncreads++;
			else
				mp->mnt_stat.f_syncreads++;
		}
	}
	KASSERT(devsw(bp->b_dev) != NULL, 
	   ("No devsw on dev %s responsible for buffer %p\n", 
	   devtoname(bp->b_dev), bp));
	KASSERT(devsw(bp->b_dev)->d_strategy != NULL, 
	   ("No strategy on dev %s responsible for buffer %p\n", 
	   devtoname(bp->b_dev), bp));
	DEV_STRATEGY(bp, 0);
	return (0);
}

static int
spec_freeblks(ap)
	struct vop_freeblks_args /* {
		struct vnode *a_vp;
		daddr_t a_addr;
		daddr_t a_length;
	} */ *ap;
{
	struct cdevsw *bsw;
	struct buf *bp;

	/*
	 * XXX: This assumes that strategy does the deed right away.
	 * XXX: this may not be TRTTD.
	 */
	bsw = devsw(ap->a_vp->v_rdev);
	if ((bsw->d_flags & D_CANFREE) == 0)
		return (0);
	bp = geteblk(ap->a_length);
	bp->b_iocmd = BIO_DELETE;
	bp->b_dev = ap->a_vp->v_rdev;
	bp->b_blkno = ap->a_addr;
	bp->b_offset = dbtob(ap->a_addr);
	bp->b_bcount = ap->a_length;
	BUF_KERNPROC(bp);
	DEV_STRATEGY(bp, 0);
	return (0);
}

/*
 * Implement degenerate case where the block requested is the block
 * returned, and assume that the entire device is contiguous in regards
 * to the contiguous block range (runp and runb).
 */
static int
spec_bmap(ap)
	struct vop_bmap_args /* {
		struct vnode *a_vp;
		daddr_t  a_bn;
		struct vnode **a_vpp;
		daddr_t *a_bnp;
		int *a_runp;
		int *a_runb;
	} */ *ap;
{
	struct vnode *vp = ap->a_vp;
	int runp = 0;
	int runb = 0;

	if (ap->a_vpp != NULL)
		*ap->a_vpp = vp;
	if (ap->a_bnp != NULL)
		*ap->a_bnp = ap->a_bn;
	if (vp->v_mount != NULL)
		runp = runb = MAXBSIZE / vp->v_mount->mnt_stat.f_iosize;
	if (ap->a_runp != NULL)
		*ap->a_runp = runp;
	if (ap->a_runb != NULL)
		*ap->a_runb = runb;
	return (0);
}

/*
 * Device close routine
 */
/* ARGSUSED */
static int
spec_close(ap)
	struct vop_close_args /* {
		struct vnode *a_vp;
		int  a_fflag;
		struct ucred *a_cred;
		struct proc *a_p;
	} */ *ap;
{
	struct vnode *vp = ap->a_vp;
	struct proc *p = ap->a_p;
	dev_t dev = vp->v_rdev;

	/*
	 * Hack: a tty device that is a controlling terminal
	 * has a reference from the session structure.
	 * We cannot easily tell that a character device is
	 * a controlling terminal, unless it is the closing
	 * process' controlling terminal.  In that case,
	 * if the reference count is 2 (this last descriptor
	 * plus the session), release the reference from the session.
	 */
	if (vcount(vp) == 2 && p && (vp->v_flag & VXLOCK) == 0 &&
	    vp == p->p_session->s_ttyvp) {
		vrele(vp);
		p->p_session->s_ttyvp = NULL;
	}
	/*
	 * We do not want to really close the device if it
	 * is still in use unless we are trying to close it
	 * forcibly. Since every use (buffer, vnode, swap, cmap)
	 * holds a reference to the vnode, and because we mark
	 * any other vnodes that alias this device, when the
	 * sum of the reference counts on all the aliased
	 * vnodes descends to one, we are on last close.
	 */
	if (vp->v_flag & VXLOCK) {
		/* Forced close */
	} else if (devsw(dev)->d_flags & D_TRACKCLOSE) {
		/* Keep device updated on status */
	} else if (vcount(vp) > 1) {
		return (0);
	}
	return (devsw(dev)->d_close(dev, ap->a_fflag, S_IFCHR, p));
}

/*
 * Print out the contents of a special device vnode.
 */
static int
spec_print(ap)
	struct vop_print_args /* {
		struct vnode *a_vp;
	} */ *ap;
{

	printf("tag VT_NON, dev %s\n", devtoname(ap->a_vp->v_rdev));
	return (0);
}

/*
 * Special device advisory byte-level locks.
 */
/* ARGSUSED */
static int
spec_advlock(ap)
	struct vop_advlock_args /* {
		struct vnode *a_vp;
		caddr_t  a_id;
		int  a_op;
		struct flock *a_fl;
		int  a_flags;
	} */ *ap;
{

	return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL);
}

static void
spec_getpages_iodone(bp)
	struct buf *bp;
{

	bp->b_flags |= B_DONE;
	wakeup(bp);
}

static int
spec_getpages(ap)
	struct vop_getpages_args *ap;
{
	vm_offset_t kva;
	int error;
	int i, pcount, size, s;
	daddr_t blkno;
	struct buf *bp;
	vm_page_t m;
	vm_ooffset_t offset;
	int toff, nextoff, nread;
	struct vnode *vp = ap->a_vp;
	int blksiz;
	int gotreqpage;

	error = 0;
	pcount = round_page(ap->a_count) / PAGE_SIZE;

	/*
	 * Calculate the offset of the transfer and do sanity check.
	 * FreeBSD currently only supports an 8 TB range due to b_blkno
	 * being in DEV_BSIZE ( usually 512 ) byte chunks on call to
	 * VOP_STRATEGY.  XXX
	 */
	offset = IDX_TO_OFF(ap->a_m[0]->pindex) + ap->a_offset;

#define	DADDR_T_BIT	(sizeof(daddr_t)*8)
#define	OFFSET_MAX	((1LL << (DADDR_T_BIT + DEV_BSHIFT)) - 1)

	if (offset < 0 || offset > OFFSET_MAX) {
		/* XXX still no %q in kernel. */
		printf("spec_getpages: preposterous offset 0x%x%08x\n",
		       (u_int)((u_quad_t)offset >> 32),
		       (u_int)(offset & 0xffffffff));
		return (VM_PAGER_ERROR);
	}

	blkno = btodb(offset);

	/*
	 * Round up physical size for real devices.  We cannot round using
	 * v_mount's block size data because v_mount has nothing to do with
	 * the device.  i.e. it's usually '/dev'.  We need the physical block
	 * size for the device itself.
	 *
	 * We can't use v_rdev->si_mountpoint because it only exists when the
	 * block device is mounted.  However, we can use v_rdev.
	 */

	if (vn_isdisk(vp, NULL))
		blksiz = vp->v_rdev->si_bsize_phys;
	else
		blksiz = DEV_BSIZE;

	size = (ap->a_count + blksiz - 1) & ~(blksiz - 1);

	bp = getpbuf(NULL);
	kva = (vm_offset_t)bp->b_data;

	/*
	 * Map the pages to be read into the kva.
	 */
	pmap_qenter(kva, ap->a_m, pcount);

	/* Build a minimal buffer header. */
	bp->b_iocmd = BIO_READ;
	bp->b_iodone = spec_getpages_iodone;

	/* B_PHYS is not set, but it is nice to fill this in. */
	bp->b_rcred = bp->b_wcred = curproc->p_ucred;
	if (bp->b_rcred != NOCRED)
		crhold(bp->b_rcred);
	if (bp->b_wcred != NOCRED)
		crhold(bp->b_wcred);
	bp->b_blkno = blkno;
	bp->b_lblkno = blkno;
	pbgetvp(ap->a_vp, bp);
	bp->b_bcount = size;
	bp->b_bufsize = size;
	bp->b_resid = 0;
	bp->b_runningbufspace = bp->b_bufsize;
	runningbufspace += bp->b_runningbufspace;

	cnt.v_vnodein++;
	cnt.v_vnodepgsin += pcount;

	/* Do the input. */
	BUF_STRATEGY(bp);

	s = splbio();

	/* We definitely need to be at splbio here. */
	while ((bp->b_flags & B_DONE) == 0)
		tsleep(bp, PVM, "spread", 0);

	splx(s);

	if ((bp->b_ioflags & BIO_ERROR) != 0) {
		if (bp->b_error)
			error = bp->b_error;
		else
			error = EIO;
	}

	nread = size - bp->b_resid;

	if (nread < ap->a_count) {
		bzero((caddr_t)kva + nread,
			ap->a_count - nread);
	}
	pmap_qremove(kva, pcount);


	gotreqpage = 0;
	for (i = 0, toff = 0; i < pcount; i++, toff = nextoff) {
		nextoff = toff + PAGE_SIZE;
		m = ap->a_m[i];

		m->flags &= ~PG_ZERO;

		if (nextoff <= nread) {
			m->valid = VM_PAGE_BITS_ALL;
			vm_page_undirty(m);
		} else if (toff < nread) {
			/*
			 * Since this is a VM request, we have to supply the
			 * unaligned offset to allow vm_page_set_validclean()
			 * to zero sub-DEV_BSIZE'd portions of the page.
			 */
			vm_page_set_validclean(m, 0, nread - toff);
		} else {
			m->valid = 0;
			vm_page_undirty(m);
		}

		if (i != ap->a_reqpage) {
			/*
			 * Just in case someone was asking for this page we
			 * now tell them that it is ok to use.
			 */
			if (!error || (m->valid == VM_PAGE_BITS_ALL)) {
				if (m->valid) {
					if (m->flags & PG_WANTED) {
						vm_page_activate(m);
					} else {
						vm_page_deactivate(m);
					}
					vm_page_wakeup(m);
				} else {
					vm_page_free(m);
				}
			} else {
				vm_page_free(m);
			}
		} else if (m->valid) {
			gotreqpage = 1;
			/*
			 * Since this is a VM request, we need to make the
			 * entire page presentable by zeroing invalid sections.
			 */
			if (m->valid != VM_PAGE_BITS_ALL)
			    vm_page_zero_invalid(m, FALSE);
		}
	}
	if (!gotreqpage) {
		m = ap->a_m[ap->a_reqpage];
		printf(
	    "spec_getpages:(%s) I/O read failure: (error=%d) bp %p vp %p\n",
			devtoname(bp->b_dev), error, bp, bp->b_vp);
		printf(
	    "               size: %d, resid: %ld, a_count: %d, valid: 0x%x\n",
		    size, bp->b_resid, ap->a_count, m->valid);
		printf(
	    "               nread: %d, reqpage: %d, pindex: %lu, pcount: %d\n",
		    nread, ap->a_reqpage, (u_long)m->pindex, pcount);
		/*
		 * Free the buffer header back to the swap buffer pool.
		 */
		relpbuf(bp, NULL);
		return VM_PAGER_ERROR;
	}
	/*
	 * Free the buffer header back to the swap buffer pool.
	 */
	relpbuf(bp, NULL);
	return VM_PAGER_OK;
}
OpenPOWER on IntegriCloud