Initial import from FreeBSD RELENG_4:
[dragonfly.git] / sys / vfs / specfs / spec_vnops.c
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1/*
2 * Copyright (c) 1989, 1993, 1995
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)spec_vnops.c 8.14 (Berkeley) 5/21/95
34 * $FreeBSD: src/sys/miscfs/specfs/spec_vnops.c,v 1.131.2.4 2001/02/26 04:23:20 jlemon Exp $
35 */
36
37#include <sys/param.h>
38#include <sys/proc.h>
39#include <sys/systm.h>
40#include <sys/kernel.h>
41#include <sys/conf.h>
42#include <sys/buf.h>
43#include <sys/mount.h>
44#include <sys/vnode.h>
45#include <sys/stat.h>
46#include <sys/fcntl.h>
47#include <sys/vmmeter.h>
48#include <sys/tty.h>
49
50#include <vm/vm.h>
51#include <vm/vm_object.h>
52#include <vm/vm_page.h>
53#include <vm/vm_pager.h>
54
55static int spec_advlock __P((struct vop_advlock_args *));
56static int spec_bmap __P((struct vop_bmap_args *));
57static int spec_close __P((struct vop_close_args *));
58static int spec_freeblks __P((struct vop_freeblks_args *));
59static int spec_fsync __P((struct vop_fsync_args *));
60static int spec_getpages __P((struct vop_getpages_args *));
61static int spec_inactive __P((struct vop_inactive_args *));
62static int spec_ioctl __P((struct vop_ioctl_args *));
63static int spec_open __P((struct vop_open_args *));
64static int spec_poll __P((struct vop_poll_args *));
65static int spec_kqfilter __P((struct vop_kqfilter_args *));
66static int spec_print __P((struct vop_print_args *));
67static int spec_read __P((struct vop_read_args *));
68static int spec_strategy __P((struct vop_strategy_args *));
69static int spec_write __P((struct vop_write_args *));
70
71vop_t **spec_vnodeop_p;
72static struct vnodeopv_entry_desc spec_vnodeop_entries[] = {
73 { &vop_default_desc, (vop_t *) vop_defaultop },
74 { &vop_access_desc, (vop_t *) vop_ebadf },
75 { &vop_advlock_desc, (vop_t *) spec_advlock },
76 { &vop_bmap_desc, (vop_t *) spec_bmap },
77 { &vop_close_desc, (vop_t *) spec_close },
78 { &vop_create_desc, (vop_t *) vop_panic },
79 { &vop_freeblks_desc, (vop_t *) spec_freeblks },
80 { &vop_fsync_desc, (vop_t *) spec_fsync },
81 { &vop_getpages_desc, (vop_t *) spec_getpages },
82 { &vop_inactive_desc, (vop_t *) spec_inactive },
83 { &vop_ioctl_desc, (vop_t *) spec_ioctl },
84 { &vop_lease_desc, (vop_t *) vop_null },
85 { &vop_link_desc, (vop_t *) vop_panic },
86 { &vop_mkdir_desc, (vop_t *) vop_panic },
87 { &vop_mknod_desc, (vop_t *) vop_panic },
88 { &vop_open_desc, (vop_t *) spec_open },
89 { &vop_pathconf_desc, (vop_t *) vop_stdpathconf },
90 { &vop_poll_desc, (vop_t *) spec_poll },
91 { &vop_kqfilter_desc, (vop_t *) spec_kqfilter },
92 { &vop_print_desc, (vop_t *) spec_print },
93 { &vop_read_desc, (vop_t *) spec_read },
94 { &vop_readdir_desc, (vop_t *) vop_panic },
95 { &vop_readlink_desc, (vop_t *) vop_panic },
96 { &vop_reallocblks_desc, (vop_t *) vop_panic },
97 { &vop_reclaim_desc, (vop_t *) vop_null },
98 { &vop_remove_desc, (vop_t *) vop_panic },
99 { &vop_rename_desc, (vop_t *) vop_panic },
100 { &vop_rmdir_desc, (vop_t *) vop_panic },
101 { &vop_setattr_desc, (vop_t *) vop_ebadf },
102 { &vop_strategy_desc, (vop_t *) spec_strategy },
103 { &vop_symlink_desc, (vop_t *) vop_panic },
104 { &vop_write_desc, (vop_t *) spec_write },
105 { NULL, NULL }
106};
107static struct vnodeopv_desc spec_vnodeop_opv_desc =
108 { &spec_vnodeop_p, spec_vnodeop_entries };
109
110VNODEOP_SET(spec_vnodeop_opv_desc);
111
112int
113spec_vnoperate(ap)
114 struct vop_generic_args /* {
115 struct vnodeop_desc *a_desc;
116 <other random data follows, presumably>
117 } */ *ap;
118{
119 return (VOCALL(spec_vnodeop_p, ap->a_desc->vdesc_offset, ap));
120}
121
122static void spec_getpages_iodone __P((struct buf *bp));
123
124/*
125 * Open a special file.
126 */
127/* ARGSUSED */
128static int
129spec_open(ap)
130 struct vop_open_args /* {
131 struct vnode *a_vp;
132 int a_mode;
133 struct ucred *a_cred;
134 struct proc *a_p;
135 } */ *ap;
136{
137 struct proc *p = ap->a_p;
138 struct vnode *vp = ap->a_vp;
139 dev_t dev = vp->v_rdev;
140 int error;
141 struct cdevsw *dsw;
142 const char *cp;
143
144 /*
145 * Don't allow open if fs is mounted -nodev.
146 */
147 if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_NODEV))
148 return (ENXIO);
149
150 dsw = devsw(dev);
151 if ( (dsw == NULL) || (dsw->d_open == NULL))
152 return ENXIO;
153
154 /* Make this field valid before any I/O in ->d_open */
155 if (!dev->si_iosize_max)
156 dev->si_iosize_max = DFLTPHYS;
157
158 /*
159 * XXX: Disks get special billing here, but it is mostly wrong.
160 * XXX: diskpartitions can overlap and the real checks should
161 * XXX: take this into account, and consequently they need to
162 * XXX: live in the diskslicing code. Some checks do.
163 */
164 if (vn_isdisk(vp, NULL) && ap->a_cred != FSCRED &&
165 (ap->a_mode & FWRITE)) {
166 /*
167 * Never allow opens for write if the device is mounted R/W
168 */
169 if (vp->v_specmountpoint != NULL &&
170 !(vp->v_specmountpoint->mnt_flag & MNT_RDONLY))
171 return (EBUSY);
172
173 /*
174 * When running in secure mode, do not allow opens
175 * for writing if the device is mounted
176 */
177 if (securelevel >= 1 && vp->v_specmountpoint != NULL)
178 return (EPERM);
179
180 /*
181 * When running in very secure mode, do not allow
182 * opens for writing of any devices.
183 */
184 if (securelevel >= 2)
185 return (EPERM);
186 }
187
188 /* XXX: Special casing of ttys for deadfs. Probably redundant */
189 if (dsw->d_flags & D_TTY)
190 vp->v_flag |= VISTTY;
191
192 VOP_UNLOCK(vp, 0, p);
193 error = (*dsw->d_open)(dev, ap->a_mode, S_IFCHR, p);
194 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
195
196 if (error)
197 return (error);
198
199 if (dsw->d_flags & D_TTY) {
200 if (dev->si_tty) {
201 struct tty *tp;
202 tp = dev->si_tty;
203 if (!tp->t_stop) {
204 printf("Warning:%s: no t_stop, using nottystop\n", devtoname(dev));
205 tp->t_stop = nottystop;
206 }
207 }
208 }
209
210 if (vn_isdisk(vp, NULL)) {
211 if (!dev->si_bsize_phys)
212 dev->si_bsize_phys = DEV_BSIZE;
213 }
214 if ((dsw->d_flags & D_DISK) == 0) {
215 cp = devtoname(dev);
216 if (*cp == '#' && (dsw->d_flags & D_NAGGED) == 0) {
217 printf("WARNING: driver %s should register devices with make_dev() (dev_t = \"%s\")\n",
218 dsw->d_name, cp);
219 dsw->d_flags |= D_NAGGED;
220 }
221 }
222 return (error);
223}
224
225/*
226 * Vnode op for read
227 */
228/* ARGSUSED */
229static int
230spec_read(ap)
231 struct vop_read_args /* {
232 struct vnode *a_vp;
233 struct uio *a_uio;
234 int a_ioflag;
235 struct ucred *a_cred;
236 } */ *ap;
237{
238 struct vnode *vp;
239 struct proc *p;
240 struct uio *uio;
241 dev_t dev;
242 int error;
243
244 vp = ap->a_vp;
245 dev = vp->v_rdev;
246 uio = ap->a_uio;
247 p = uio->uio_procp;
248
249 if (uio->uio_resid == 0)
250 return (0);
251
252 VOP_UNLOCK(vp, 0, p);
253 error = (*devsw(dev)->d_read) (dev, uio, ap->a_ioflag);
254 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
255 return (error);
256}
257
258/*
259 * Vnode op for write
260 */
261/* ARGSUSED */
262static int
263spec_write(ap)
264 struct vop_write_args /* {
265 struct vnode *a_vp;
266 struct uio *a_uio;
267 int a_ioflag;
268 struct ucred *a_cred;
269 } */ *ap;
270{
271 struct vnode *vp;
272 struct proc *p;
273 struct uio *uio;
274 dev_t dev;
275 int error;
276
277 vp = ap->a_vp;
278 dev = vp->v_rdev;
279 uio = ap->a_uio;
280 p = uio->uio_procp;
281
282 VOP_UNLOCK(vp, 0, p);
283 error = (*devsw(dev)->d_write) (dev, uio, ap->a_ioflag);
284 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
285 return (error);
286}
287
288/*
289 * Device ioctl operation.
290 */
291/* ARGSUSED */
292static int
293spec_ioctl(ap)
294 struct vop_ioctl_args /* {
295 struct vnode *a_vp;
296 int a_command;
297 caddr_t a_data;
298 int a_fflag;
299 struct ucred *a_cred;
300 struct proc *a_p;
301 } */ *ap;
302{
303 dev_t dev;
304
305 dev = ap->a_vp->v_rdev;
306 return ((*devsw(dev)->d_ioctl)(dev, ap->a_command,
307 ap->a_data, ap->a_fflag, ap->a_p));
308}
309
310/* ARGSUSED */
311static int
312spec_poll(ap)
313 struct vop_poll_args /* {
314 struct vnode *a_vp;
315 int a_events;
316 struct ucred *a_cred;
317 struct proc *a_p;
318 } */ *ap;
319{
320 dev_t dev;
321
322 dev = ap->a_vp->v_rdev;
323 return (*devsw(dev)->d_poll)(dev, ap->a_events, ap->a_p);
324}
325
326/* ARGSUSED */
327static int
328spec_kqfilter(ap)
329 struct vop_kqfilter_args /* {
330 struct vnode *a_vp;
331 struct knote *a_kn;
332 } */ *ap;
333{
334 dev_t dev;
335
336 dev = ap->a_vp->v_rdev;
337 if (devsw(dev)->d_flags & D_KQFILTER)
338 return (*devsw(dev)->d_kqfilter)(dev, ap->a_kn);
339 return (1);
340}
341
342/*
343 * Synch buffers associated with a block device
344 */
345/* ARGSUSED */
346static int
347spec_fsync(ap)
348 struct vop_fsync_args /* {
349 struct vnode *a_vp;
350 struct ucred *a_cred;
351 int a_waitfor;
352 struct proc *a_p;
353 } */ *ap;
354{
355 struct vnode *vp = ap->a_vp;
356 struct buf *bp;
357 struct buf *nbp;
358 int s;
359 int maxretry = 10000; /* large, arbitrarily chosen */
360
361 if (!vn_isdisk(vp, NULL))
362 return (0);
363
364loop1:
365 /*
366 * MARK/SCAN initialization to avoid infinite loops
367 */
368 s = splbio();
369 for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp;
370 bp = TAILQ_NEXT(bp, b_vnbufs)) {
371 bp->b_flags &= ~B_SCANNED;
372 }
373 splx(s);
374
375 /*
376 * Flush all dirty buffers associated with a block device.
377 */
378loop2:
379 s = splbio();
380 for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
381 nbp = TAILQ_NEXT(bp, b_vnbufs);
382 if ((bp->b_flags & B_SCANNED) != 0)
383 continue;
384 bp->b_flags |= B_SCANNED;
385 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT))
386 continue;
387 if ((bp->b_flags & B_DELWRI) == 0)
388 panic("spec_fsync: not dirty");
389 if ((vp->v_flag & VOBJBUF) && (bp->b_flags & B_CLUSTEROK)) {
390 BUF_UNLOCK(bp);
391 vfs_bio_awrite(bp);
392 splx(s);
393 } else {
394 bremfree(bp);
395 splx(s);
396 bawrite(bp);
397 }
398 goto loop2;
399 }
400
401 /*
402 * If synchronous the caller expects us to completely resolve all
403 * dirty buffers in the system. Wait for in-progress I/O to
404 * complete (which could include background bitmap writes), then
405 * retry if dirty blocks still exist.
406 */
407 if (ap->a_waitfor == MNT_WAIT) {
408 while (vp->v_numoutput) {
409 vp->v_flag |= VBWAIT;
410 (void) tsleep((caddr_t)&vp->v_numoutput, PRIBIO + 1, "spfsyn", 0);
411 }
412 if (!TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
413 if (--maxretry != 0) {
414 splx(s);
415 goto loop1;
416 }
417 vprint("spec_fsync: giving up on dirty", vp);
418 }
419 }
420 splx(s);
421 return (0);
422}
423
424static int
425spec_inactive(ap)
426 struct vop_inactive_args /* {
427 struct vnode *a_vp;
428 struct proc *a_p;
429 } */ *ap;
430{
431
432 VOP_UNLOCK(ap->a_vp, 0, ap->a_p);
433 return (0);
434}
435
436/*
437 * Just call the device strategy routine
438 */
439static int
440spec_strategy(ap)
441 struct vop_strategy_args /* {
442 struct vnode *a_vp;
443 struct buf *a_bp;
444 } */ *ap;
445{
446 struct buf *bp;
447 struct vnode *vp;
448 struct mount *mp;
449
450 bp = ap->a_bp;
451 if (((bp->b_flags & B_READ) == 0) &&
452 (LIST_FIRST(&bp->b_dep)) != NULL && bioops.io_start)
453 (*bioops.io_start)(bp);
454
455 /*
456 * Collect statistics on synchronous and asynchronous read
457 * and write counts for disks that have associated filesystems.
458 */
459 vp = ap->a_vp;
460 if (vn_isdisk(vp, NULL) && (mp = vp->v_specmountpoint) != NULL) {
461 if ((bp->b_flags & B_READ) == 0) {
462 if (bp->b_lock.lk_lockholder == LK_KERNPROC)
463 mp->mnt_stat.f_asyncwrites++;
464 else
465 mp->mnt_stat.f_syncwrites++;
466 } else {
467 if (bp->b_lock.lk_lockholder == LK_KERNPROC)
468 mp->mnt_stat.f_asyncreads++;
469 else
470 mp->mnt_stat.f_syncreads++;
471 }
472 }
473 KASSERT(devsw(bp->b_dev) != NULL,
474 ("No devsw on dev %s responsible for buffer %p\n",
475 devtoname(bp->b_dev), bp));
476 KASSERT(devsw(bp->b_dev)->d_strategy != NULL,
477 ("No strategy on dev %s responsible for buffer %p\n",
478 devtoname(bp->b_dev), bp));
479 BUF_STRATEGY(bp, 0);
480 return (0);
481}
482
483static int
484spec_freeblks(ap)
485 struct vop_freeblks_args /* {
486 struct vnode *a_vp;
487 daddr_t a_addr;
488 daddr_t a_length;
489 } */ *ap;
490{
491 struct cdevsw *bsw;
492 struct buf *bp;
493
494 /*
495 * XXX: This assumes that strategy does the deed right away.
496 * XXX: this may not be TRTTD.
497 */
498 bsw = devsw(ap->a_vp->v_rdev);
499 if ((bsw->d_flags & D_CANFREE) == 0)
500 return (0);
501 bp = geteblk(ap->a_length);
502 bp->b_flags |= B_FREEBUF;
503 bp->b_dev = ap->a_vp->v_rdev;
504 bp->b_blkno = ap->a_addr;
505 bp->b_offset = dbtob(ap->a_addr);
506 bp->b_bcount = ap->a_length;
507 BUF_STRATEGY(bp, 0);
508 return (0);
509}
510
511/*
512 * Implement degenerate case where the block requested is the block
513 * returned, and assume that the entire device is contiguous in regards
514 * to the contiguous block range (runp and runb).
515 */
516static int
517spec_bmap(ap)
518 struct vop_bmap_args /* {
519 struct vnode *a_vp;
520 daddr_t a_bn;
521 struct vnode **a_vpp;
522 daddr_t *a_bnp;
523 int *a_runp;
524 int *a_runb;
525 } */ *ap;
526{
527 struct vnode *vp = ap->a_vp;
528 int runp = 0;
529 int runb = 0;
530
531 if (ap->a_vpp != NULL)
532 *ap->a_vpp = vp;
533 if (ap->a_bnp != NULL)
534 *ap->a_bnp = ap->a_bn;
535 if (vp->v_mount != NULL)
536 runp = runb = MAXBSIZE / vp->v_mount->mnt_stat.f_iosize;
537 if (ap->a_runp != NULL)
538 *ap->a_runp = runp;
539 if (ap->a_runb != NULL)
540 *ap->a_runb = runb;
541 return (0);
542}
543
544/*
545 * Device close routine
546 */
547/* ARGSUSED */
548static int
549spec_close(ap)
550 struct vop_close_args /* {
551 struct vnode *a_vp;
552 int a_fflag;
553 struct ucred *a_cred;
554 struct proc *a_p;
555 } */ *ap;
556{
557 struct vnode *vp = ap->a_vp;
558 struct proc *p = ap->a_p;
559 dev_t dev = vp->v_rdev;
560
561 /*
562 * Hack: a tty device that is a controlling terminal
563 * has a reference from the session structure.
564 * We cannot easily tell that a character device is
565 * a controlling terminal, unless it is the closing
566 * process' controlling terminal. In that case,
567 * if the reference count is 2 (this last descriptor
568 * plus the session), release the reference from the session.
569 */
570 if (vcount(vp) == 2 && p && (vp->v_flag & VXLOCK) == 0 &&
571 vp == p->p_session->s_ttyvp) {
572 vrele(vp);
573 p->p_session->s_ttyvp = NULL;
574 }
575 /*
576 * We do not want to really close the device if it
577 * is still in use unless we are trying to close it
578 * forcibly. Since every use (buffer, vnode, swap, cmap)
579 * holds a reference to the vnode, and because we mark
580 * any other vnodes that alias this device, when the
581 * sum of the reference counts on all the aliased
582 * vnodes descends to one, we are on last close.
583 */
584 if (vp->v_flag & VXLOCK) {
585 /* Forced close */
586 } else if (devsw(dev)->d_flags & D_TRACKCLOSE) {
587 /* Keep device updated on status */
588 } else if (vcount(vp) > 1) {
589 return (0);
590 }
591 return (devsw(dev)->d_close(dev, ap->a_fflag, S_IFCHR, p));
592}
593
594/*
595 * Print out the contents of a special device vnode.
596 */
597static int
598spec_print(ap)
599 struct vop_print_args /* {
600 struct vnode *a_vp;
601 } */ *ap;
602{
603
604 printf("tag VT_NON, dev %s\n", devtoname(ap->a_vp->v_rdev));
605 return (0);
606}
607
608/*
609 * Special device advisory byte-level locks.
610 */
611/* ARGSUSED */
612static int
613spec_advlock(ap)
614 struct vop_advlock_args /* {
615 struct vnode *a_vp;
616 caddr_t a_id;
617 int a_op;
618 struct flock *a_fl;
619 int a_flags;
620 } */ *ap;
621{
622
623 return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL);
624}
625
626static void
627spec_getpages_iodone(bp)
628 struct buf *bp;
629{
630
631 bp->b_flags |= B_DONE;
632 wakeup(bp);
633}
634
635static int
636spec_getpages(ap)
637 struct vop_getpages_args *ap;
638{
639 vm_offset_t kva;
640 int error;
641 int i, pcount, size, s;
642 daddr_t blkno;
643 struct buf *bp;
644 vm_page_t m;
645 vm_ooffset_t offset;
646 int toff, nextoff, nread;
647 struct vnode *vp = ap->a_vp;
648 int blksiz;
649 int gotreqpage;
650
651 error = 0;
652 pcount = round_page(ap->a_count) / PAGE_SIZE;
653
654 /*
655 * Calculate the offset of the transfer and do sanity check.
656 * FreeBSD currently only supports an 8 TB range due to b_blkno
657 * being in DEV_BSIZE ( usually 512 ) byte chunks on call to
658 * VOP_STRATEGY. XXX
659 */
660 offset = IDX_TO_OFF(ap->a_m[0]->pindex) + ap->a_offset;
661
662#define DADDR_T_BIT (sizeof(daddr_t)*8)
663#define OFFSET_MAX ((1LL << (DADDR_T_BIT + DEV_BSHIFT)) - 1)
664
665 if (offset < 0 || offset > OFFSET_MAX) {
666 /* XXX still no %q in kernel. */
667 printf("spec_getpages: preposterous offset 0x%x%08x\n",
668 (u_int)((u_quad_t)offset >> 32),
669 (u_int)(offset & 0xffffffff));
670 return (VM_PAGER_ERROR);
671 }
672
673 blkno = btodb(offset);
674
675 /*
676 * Round up physical size for real devices. We cannot round using
677 * v_mount's block size data because v_mount has nothing to do with
678 * the device. i.e. it's usually '/dev'. We need the physical block
679 * size for the device itself.
680 *
681 * We can't use v_specmountpoint because it only exists when the
682 * block device is mounted. However, we can use v_rdev.
683 */
684
685 if (vn_isdisk(vp, NULL))
686 blksiz = vp->v_rdev->si_bsize_phys;
687 else
688 blksiz = DEV_BSIZE;
689
690 size = (ap->a_count + blksiz - 1) & ~(blksiz - 1);
691
692 bp = getpbuf(NULL);
693 kva = (vm_offset_t)bp->b_data;
694
695 /*
696 * Map the pages to be read into the kva.
697 */
698 pmap_qenter(kva, ap->a_m, pcount);
699
700 /* Build a minimal buffer header. */
701 bp->b_flags = B_READ | B_CALL;
702 bp->b_iodone = spec_getpages_iodone;
703
704 /* B_PHYS is not set, but it is nice to fill this in. */
705 bp->b_rcred = bp->b_wcred = curproc->p_ucred;
706 if (bp->b_rcred != NOCRED)
707 crhold(bp->b_rcred);
708 if (bp->b_wcred != NOCRED)
709 crhold(bp->b_wcred);
710 bp->b_blkno = blkno;
711 bp->b_lblkno = blkno;
712 pbgetvp(ap->a_vp, bp);
713 bp->b_bcount = size;
714 bp->b_bufsize = size;
715 bp->b_resid = 0;
716 bp->b_runningbufspace = bp->b_bufsize;
717 runningbufspace += bp->b_runningbufspace;
718
719 cnt.v_vnodein++;
720 cnt.v_vnodepgsin += pcount;
721
722 /* Do the input. */
723 VOP_STRATEGY(bp->b_vp, bp);
724
725 s = splbio();
726
727 /* We definitely need to be at splbio here. */
728 while ((bp->b_flags & B_DONE) == 0)
729 tsleep(bp, PVM, "spread", 0);
730
731 splx(s);
732
733 if ((bp->b_flags & B_ERROR) != 0) {
734 if (bp->b_error)
735 error = bp->b_error;
736 else
737 error = EIO;
738 }
739
740 nread = size - bp->b_resid;
741
742 if (nread < ap->a_count) {
743 bzero((caddr_t)kva + nread,
744 ap->a_count - nread);
745 }
746 pmap_qremove(kva, pcount);
747
748
749 gotreqpage = 0;
750 for (i = 0, toff = 0; i < pcount; i++, toff = nextoff) {
751 nextoff = toff + PAGE_SIZE;
752 m = ap->a_m[i];
753
754 m->flags &= ~PG_ZERO;
755
756 if (nextoff <= nread) {
757 m->valid = VM_PAGE_BITS_ALL;
758 vm_page_undirty(m);
759 } else if (toff < nread) {
760 /*
761 * Since this is a VM request, we have to supply the
762 * unaligned offset to allow vm_page_set_validclean()
763 * to zero sub-DEV_BSIZE'd portions of the page.
764 */
765 vm_page_set_validclean(m, 0, nread - toff);
766 } else {
767 m->valid = 0;
768 vm_page_undirty(m);
769 }
770
771 if (i != ap->a_reqpage) {
772 /*
773 * Just in case someone was asking for this page we
774 * now tell them that it is ok to use.
775 */
776 if (!error || (m->valid == VM_PAGE_BITS_ALL)) {
777 if (m->valid) {
778 if (m->flags & PG_WANTED) {
779 vm_page_activate(m);
780 } else {
781 vm_page_deactivate(m);
782 }
783 vm_page_wakeup(m);
784 } else {
785 vm_page_free(m);
786 }
787 } else {
788 vm_page_free(m);
789 }
790 } else if (m->valid) {
791 gotreqpage = 1;
792 /*
793 * Since this is a VM request, we need to make the
794 * entire page presentable by zeroing invalid sections.
795 */
796 if (m->valid != VM_PAGE_BITS_ALL)
797 vm_page_zero_invalid(m, FALSE);
798 }
799 }
800 if (!gotreqpage) {
801 m = ap->a_m[ap->a_reqpage];
802 printf(
803 "spec_getpages:(%s) I/O read failure: (error=%d) bp %p vp %p\n",
804 devtoname(bp->b_dev), error, bp, bp->b_vp);
805 printf(
806 " size: %d, resid: %ld, a_count: %d, valid: 0x%x\n",
807 size, bp->b_resid, ap->a_count, m->valid);
808 printf(
809 " nread: %d, reqpage: %d, pindex: %lu, pcount: %d\n",
810 nread, ap->a_reqpage, (u_long)m->pindex, pcount);
811 /*
812 * Free the buffer header back to the swap buffer pool.
813 */
814 relpbuf(bp, NULL);
815 return VM_PAGER_ERROR;
816 }
817 /*
818 * Free the buffer header back to the swap buffer pool.
819 */
820 relpbuf(bp, NULL);
821 return VM_PAGER_OK;
822}