1 /*
2 * (MPSAFE)
3 *
4 * Copyright (c) 1990 University of Utah.
5 * Copyright (c) 1991 The Regents of the University of California.
6 * All rights reserved.
7 * Copyright (c) 1993, 1994 John S. Dyson
8 * Copyright (c) 1995, David Greenman
9 *
10 * This code is derived from software contributed to Berkeley by
11 * the Systems Programming Group of the University of Utah Computer
12 * Science Department.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 * 3. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91
39 * $FreeBSD: src/sys/vm/vnode_pager.c,v 1.116.2.7 2002/12/31 09:34:51 dillon Exp $
40 */
41
42 /*
43 * Page to/from files (vnodes).
44 */
45
46 /*
47 * TODO:
48 * Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will
49 * greatly re-simplify the vnode_pager.
50 */
51
52 #include <sys/param.h>
53 #include <sys/systm.h>
54 #include <sys/uio.h>
55 #include <sys/kernel.h>
56 #include <sys/proc.h>
57 #include <sys/vnode.h>
58 #include <sys/mount.h>
59 #include <sys/buf.h>
60 #include <sys/vmmeter.h>
61 #include <sys/conf.h>
62
63 #include <cpu/lwbuf.h>
64
65 #include <vm/vm.h>
66 #include <vm/vm_object.h>
67 #include <vm/vm_page.h>
68 #include <vm/vm_pager.h>
69 #include <vm/vm_map.h>
70 #include <vm/vnode_pager.h>
71 #include <vm/swap_pager.h>
72 #include <vm/vm_extern.h>
73
74 #include <vm/vm_page2.h>
75
76 static pgo_dealloc_t vnode_pager_dealloc;
77 static pgo_getpage_t vnode_pager_getpage;
78 static pgo_putpages_t vnode_pager_putpages;
79 static pgo_haspage_t vnode_pager_haspage;
80
81 struct pagerops vnodepagerops = {
82 .pgo_dealloc = vnode_pager_dealloc,
83 .pgo_getpage = vnode_pager_getpage,
84 .pgo_putpages = vnode_pager_putpages,
85 .pgo_haspage = vnode_pager_haspage
86 };
87
88 static struct krate vbadrate = { 1 };
89 static struct krate vresrate = { 1 };
90
91 long vnode_pbuf_freecnt = -1; /* start out unlimited */
92
93 /*
94 * Allocate a VM object for a vnode, typically a regular file vnode.
95 *
96 * Some additional information is required to generate a properly sized
97 * object which covers the entire buffer cache buffer straddling the file
98 * EOF. Userland does not see the extra pages as the VM fault code tests
99 * against v_filesize.
100 */
101 vm_object_t
vnode_pager_alloc(void * handle,off_t length,vm_prot_t prot,off_t offset,int blksize,int boff)102 vnode_pager_alloc(void *handle, off_t length, vm_prot_t prot, off_t offset,
103 int blksize, int boff)
104 {
105 vm_object_t object;
106 struct vnode *vp;
107 off_t loffset;
108 vm_pindex_t lsize;
109
110 /*
111 * Pageout to vnode, no can do yet.
112 */
113 if (handle == NULL)
114 return (NULL);
115
116 /*
117 * XXX hack - This initialization should be put somewhere else.
118 */
119 if (vnode_pbuf_freecnt < 0) {
120 vnode_pbuf_freecnt = nswbuf_kva / 2 + 1;
121 }
122
123 /*
124 * Serialize potential vnode/object teardowns and interlocks
125 */
126 vp = (struct vnode *)handle;
127 lwkt_gettoken(&vp->v_token);
128
129 /*
130 * If the object is being terminated, wait for it to
131 * go away.
132 */
133 object = vp->v_object;
134 if (object) {
135 vm_object_hold(object);
136 KKASSERT((object->flags & OBJ_DEAD) == 0);
137 }
138
139 if (VREFCNT(vp) <= 0)
140 panic("vnode_pager_alloc: no vnode reference");
141
142 /*
143 * Round up to the *next* block, then destroy the buffers in question.
144 * Since we are only removing some of the buffers we must rely on the
145 * scan count to determine whether a loop is necessary.
146 *
147 * Destroy any pages beyond the last buffer.
148 */
149 if (boff < 0)
150 boff = (int)(length % blksize);
151 if (boff)
152 loffset = length + (blksize - boff);
153 else
154 loffset = length;
155 lsize = OFF_TO_IDX(round_page64(loffset));
156
157 if (object == NULL) {
158 /*
159 * And an object of the appropriate size
160 */
161 object = vm_object_allocate_hold(OBJT_VNODE, lsize);
162 object->handle = handle;
163 vp->v_object = object;
164 vp->v_filesize = length;
165 if (vp->v_mount && (vp->v_mount->mnt_kern_flag & MNTK_NOMSYNC))
166 vm_object_set_flag(object, OBJ_NOMSYNC);
167 vref(vp);
168 } else {
169 vm_object_reference_quick(object); /* also vref's */
170 if (object->size != lsize) {
171 kprintf("vnode_pager_alloc: Warning, objsize "
172 "mismatch %jd/%jd vp=%p obj=%p\n",
173 (intmax_t)object->size,
174 (intmax_t)lsize,
175 vp, object);
176 }
177 if (vp->v_filesize != length) {
178 kprintf("vnode_pager_alloc: Warning, filesize "
179 "mismatch %jd/%jd vp=%p obj=%p\n",
180 (intmax_t)vp->v_filesize,
181 (intmax_t)length,
182 vp, object);
183 }
184 }
185 vm_object_drop(object);
186 lwkt_reltoken(&vp->v_token);
187
188 return (object);
189 }
190
191 /*
192 * Add a ref to a vnode's existing VM object, return the object or
193 * NULL if the vnode did not have one. This does not create the
194 * object (we can't since we don't know what the proper blocksize/boff
195 * is to match the VFS's use of the buffer cache).
196 *
197 * The vnode must be referenced and is typically open. The object should
198 * be stable in this situation.
199 *
200 * Returns the object with an additional reference but not locked.
201 */
202 vm_object_t
vnode_pager_reference(struct vnode * vp)203 vnode_pager_reference(struct vnode *vp)
204 {
205 vm_object_t object;
206
207 if ((object = vp->v_object) != NULL)
208 vm_object_reference_quick(object); /* also vref's vnode */
209 return (object);
210 }
211
212 static void
vnode_pager_dealloc(vm_object_t object)213 vnode_pager_dealloc(vm_object_t object)
214 {
215 struct vnode *vp = object->handle;
216
217 if (vp == NULL)
218 panic("vnode_pager_dealloc: pager already dealloced");
219
220 vm_object_pip_wait(object, "vnpdea");
221
222 object->handle = NULL;
223 object->type = OBJT_DEAD;
224 vp->v_object = NULL;
225 vp->v_filesize = NOOFFSET;
226 vclrflags(vp, VTEXT | VOBJBUF);
227 swap_pager_freespace_all(object);
228 }
229
230 /*
231 * Return whether the vnode pager has the requested page.
232 */
233 static boolean_t
vnode_pager_haspage(vm_object_t object,vm_pindex_t pindex)234 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex)
235 {
236 struct vnode *vp = object->handle;
237 off_t loffset;
238 off_t doffset;
239 int voff;
240 int bsize;
241 int error;
242
243 /*
244 * If no vp or vp is doomed or marked transparent to VM, we do not
245 * have the page.
246 */
247 if ((vp == NULL) || (vp->v_flag & VRECLAIMED))
248 return FALSE;
249
250 /*
251 * If filesystem no longer mounted or offset beyond end of file we do
252 * not have the page.
253 */
254 loffset = IDX_TO_OFF(pindex);
255
256 if (vp->v_mount == NULL || loffset >= vp->v_filesize)
257 return FALSE;
258
259 bsize = vp->v_mount->mnt_stat.f_iosize;
260 voff = loffset % bsize;
261
262 /*
263 * XXX (obsolete - before and after pointers are now NULL)
264 *
265 * BMAP returns byte counts before and after, where after
266 * is inclusive of the base page. haspage must return page
267 * counts before and after where after does not include the
268 * base page.
269 *
270 * BMAP is allowed to return a *after of 0 for backwards
271 * compatibility. The base page is still considered valid if
272 * no error is returned.
273 */
274 error = VOP_BMAP(vp, loffset - voff, &doffset, NULL, NULL, 0);
275 if (error)
276 return TRUE;
277 if (doffset == NOOFFSET)
278 return FALSE;
279 return TRUE;
280 }
281
282 /*
283 * Lets the VM system know about a change in size for a file.
284 * We adjust our own internal size and flush any cached pages in
285 * the associated object that are affected by the size change.
286 *
287 * NOTE: This routine may be invoked as a result of a pager put
288 * operation (possibly at object termination time), so we must be careful.
289 *
290 * NOTE: vp->v_filesize is initialized to NOOFFSET (-1), be sure that
291 * we do not blow up on the case. nsize will always be >= 0, however.
292 */
293 void
vnode_pager_setsize(struct vnode * vp,vm_ooffset_t nsize)294 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize)
295 {
296 vm_pindex_t nobjsize;
297 vm_pindex_t oobjsize;
298 vm_object_t object;
299
300 object = vp->v_object;
301 if (object == NULL)
302 return;
303 vm_object_hold(object);
304 KKASSERT(vp->v_object == object);
305
306 /*
307 * Hasn't changed size
308 */
309 if (nsize == vp->v_filesize) {
310 vm_object_drop(object);
311 return;
312 }
313
314 /*
315 * Has changed size. Adjust the VM object's size and v_filesize
316 * before we start scanning pages to prevent new pages from being
317 * allocated during the scan.
318 */
319 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
320 oobjsize = object->size;
321 object->size = nobjsize;
322
323 /*
324 * File has shrunk. Toss any cached pages beyond the new EOF.
325 */
326 if (nsize < vp->v_filesize) {
327 vp->v_filesize = nsize;
328 if (nobjsize < oobjsize) {
329 vm_object_page_remove(object, nobjsize, oobjsize,
330 FALSE);
331 }
332 /*
333 * This gets rid of garbage at the end of a page that is now
334 * only partially backed by the vnode. Since we are setting
335 * the entire page valid & clean after we are done we have
336 * to be sure that the portion of the page within the file
337 * bounds is already valid. If it isn't then making it
338 * valid would create a corrupt block.
339 */
340 if (nsize & PAGE_MASK) {
341 vm_offset_t kva;
342 vm_page_t m;
343
344 m = vm_page_lookup_busy_wait(object, OFF_TO_IDX(nsize),
345 TRUE, "vsetsz");
346
347 if (m && m->valid) {
348 int base = (int)nsize & PAGE_MASK;
349 int size = PAGE_SIZE - base;
350 struct lwbuf *lwb;
351 struct lwbuf lwb_cache;
352
353 /*
354 * Clear out partial-page garbage in case
355 * the page has been mapped.
356 *
357 * This is byte aligned.
358 */
359 lwb = lwbuf_alloc(m, &lwb_cache);
360 kva = lwbuf_kva(lwb);
361 bzero((caddr_t)kva + base, size);
362 lwbuf_free(lwb);
363
364 /*
365 * XXX work around SMP data integrity race
366 * by unmapping the page from user processes.
367 * The garbage we just cleared may be mapped
368 * to a user process running on another cpu
369 * and this code is not running through normal
370 * I/O channels which handle SMP issues for
371 * us, so unmap page to synchronize all cpus.
372 *
373 * XXX should vm_pager_unmap_page() have
374 * dealt with this?
375 */
376 vm_page_protect(m, VM_PROT_NONE);
377
378 /*
379 * Clear out partial-page dirty bits. This
380 * has the side effect of setting the valid
381 * bits, but that is ok. There are a bunch
382 * of places in the VM system where we expected
383 * m->dirty == VM_PAGE_BITS_ALL. The file EOF
384 * case is one of them. If the page is still
385 * partially dirty, make it fully dirty.
386 *
387 * NOTE: We do not clear out the valid
388 * bits. This would prevent bogus_page
389 * replacement from working properly.
390 *
391 * NOTE: We do not want to clear the dirty
392 * bit for a partial DEV_BSIZE'd truncation!
393 * This is DEV_BSIZE aligned!
394 */
395 vm_page_clear_dirty_beg_nonincl(m, base, size);
396 if (m->dirty != 0)
397 m->dirty = VM_PAGE_BITS_ALL;
398 vm_page_wakeup(m);
399 } else if (m) {
400 vm_page_wakeup(m);
401 }
402 }
403 } else {
404 vp->v_filesize = nsize;
405 }
406 vm_object_drop(object);
407 }
408
409 /*
410 * Release a page busied for a getpages operation. The page may have become
411 * wired (typically due to being used by the buffer cache) or otherwise been
412 * soft-busied and cannot be freed in that case. A held page can still be
413 * freed.
414 */
415 void
vnode_pager_freepage(vm_page_t m)416 vnode_pager_freepage(vm_page_t m)
417 {
418 if ((m->busy_count & PBUSY_MASK) ||
419 m->wire_count ||
420 (m->flags & PG_NEED_COMMIT)) {
421 vm_page_activate(m);
422 vm_page_wakeup(m);
423 } else {
424 vm_page_free(m);
425 }
426 }
427
428 /*
429 * EOPNOTSUPP is no longer legal. For local media VFS's that do not
430 * implement their own VOP_GETPAGES, their VOP_GETPAGES should call to
431 * vnode_pager_generic_getpages() to implement the previous behaviour.
432 *
433 * All other FS's should use the bypass to get to the local media
434 * backing vp's VOP_GETPAGES.
435 */
436 static int
vnode_pager_getpage(vm_object_t object,vm_pindex_t pindex,vm_page_t * mpp,int seqaccess)437 vnode_pager_getpage(vm_object_t object, vm_pindex_t pindex,
438 vm_page_t *mpp, int seqaccess)
439 {
440 int rtval;
441 struct vnode *vp;
442
443 vp = object->handle;
444 rtval = VOP_GETPAGES(vp, mpp, PAGE_SIZE, 0, 0, seqaccess);
445 if (rtval == EOPNOTSUPP)
446 panic("vnode_pager: vfs's must implement vop_getpages");
447 return rtval;
448 }
449
450 /*
451 * This is now called from local media FS's to operate against their
452 * own vnodes if they fail to implement VOP_GETPAGES.
453 *
454 * With all the caching local media devices do these days there is really
455 * very little point to attempting to restrict the I/O size to contiguous
456 * blocks on-disk, especially if our caller thinks we need all the specified
457 * pages. Just construct and issue a READ.
458 */
459 int
vnode_pager_generic_getpages(struct vnode * vp,vm_page_t * mpp,int bytecount,int reqpage,int seqaccess)460 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *mpp, int bytecount,
461 int reqpage, int seqaccess)
462 {
463 struct iovec aiov;
464 struct uio auio;
465 off_t foff;
466 int error;
467 int count;
468 int i;
469 int ioflags;
470 int obytecount;
471
472 /*
473 * Do not do anything if the vnode is bad.
474 */
475 if (vp->v_mount == NULL)
476 return VM_PAGER_BAD;
477
478 /*
479 * Calculate the number of pages. Since we are paging in whole
480 * pages, adjust bytecount to be an integral multiple of the page
481 * size. It will be clipped to the file EOF later on.
482 */
483 bytecount = round_page(bytecount);
484 count = bytecount / PAGE_SIZE;
485
486 /*
487 * We could check m[reqpage]->valid here and shortcut the operation,
488 * but doing so breaks read-ahead. Instead assume that the VM
489 * system has already done at least the check, don't worry about
490 * any races, and issue the VOP_READ to allow read-ahead to function.
491 *
492 * This keeps the pipeline full for I/O bound sequentially scanned
493 * mmap()'s
494 */
495 /* don't shortcut */
496
497 /*
498 * Discard pages past the file EOF. If the requested page is past
499 * the file EOF we just leave its valid bits set to 0, the caller
500 * expects to maintain ownership of the requested page. If the
501 * entire range is past file EOF discard everything and generate
502 * a pagein error.
503 */
504 foff = IDX_TO_OFF(mpp[0]->pindex);
505 if (foff >= vp->v_filesize) {
506 for (i = 0; i < count; i++) {
507 if (i != reqpage)
508 vnode_pager_freepage(mpp[i]);
509 }
510 return VM_PAGER_ERROR;
511 }
512
513 if (foff + bytecount > vp->v_filesize) {
514 bytecount = vp->v_filesize - foff;
515 i = round_page(bytecount) / PAGE_SIZE;
516 while (count > i) {
517 --count;
518 if (count != reqpage)
519 vnode_pager_freepage(mpp[count]);
520 }
521 }
522
523 /*
524 * The size of the transfer is bytecount. bytecount will be an
525 * integral multiple of the page size unless it has been clipped
526 * to the file EOF. The transfer cannot exceed the file EOF.
527 *
528 * When dealing with real devices we must round-up to the device
529 * sector size.
530 */
531 if (vp->v_type == VBLK || vp->v_type == VCHR) {
532 int secmask = vp->v_rdev->si_bsize_phys - 1;
533 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large", secmask + 1));
534 bytecount = (bytecount + secmask) & ~secmask;
535 }
536 obytecount = bytecount;
537
538 /*
539 * Severe hack to avoid deadlocks with the buffer cache
540 */
541 for (i = 0; i < count; ++i) {
542 vm_page_t mt = mpp[i];
543
544 vm_page_io_start(mt);
545 vm_page_wakeup(mt);
546 }
547
548 /*
549 * Issue the I/O with some read-ahead if bytecount > PAGE_SIZE
550 */
551 ioflags = IO_VMIO;
552 if (seqaccess)
553 ioflags |= IO_SEQMAX << IO_SEQSHIFT;
554
555 aiov.iov_base = NULL;
556 aiov.iov_len = bytecount;
557 auio.uio_iov = &aiov;
558 auio.uio_iovcnt = 1;
559 auio.uio_offset = foff;
560 auio.uio_segflg = UIO_NOCOPY;
561 auio.uio_rw = UIO_READ;
562 auio.uio_resid = bytecount;
563 auio.uio_td = NULL;
564 mycpu->gd_cnt.v_vnodein++;
565 mycpu->gd_cnt.v_vnodepgsin += count;
566
567 error = VOP_READ(vp, &auio, ioflags, proc0.p_ucred);
568
569 /*
570 * Severe hack to avoid deadlocks with the buffer cache
571 */
572 for (i = 0; i < count; ++i) {
573 vm_page_busy_wait(mpp[i], FALSE, "getpgs");
574 vm_page_io_finish(mpp[i]);
575 }
576
577 /*
578 * Calculate the actual number of bytes read and clean up the
579 * page list.
580 */
581 bytecount -= auio.uio_resid;
582
583 for (i = 0; i < count; ++i) {
584 vm_page_t mt = mpp[i];
585
586 if (i != reqpage) {
587 if (error == 0 && mt->valid) {
588 if (mt->flags & PG_REFERENCED)
589 vm_page_activate(mt);
590 else
591 vm_page_deactivate(mt);
592 vm_page_wakeup(mt);
593 } else {
594 vnode_pager_freepage(mt);
595 }
596 } else if (mt->valid == 0) {
597 if (error == 0) {
598 kprintf("page failed but no I/O error page "
599 "%p object %p pindex %d\n",
600 mt, mt->object, (int) mt->pindex);
601 kprintf("i=%d foff=%016lx bytecount=%d/%d "
602 "uioresid=%zd\n",
603 i, foff, obytecount, bytecount,
604 auio.uio_resid);
605 /* whoops, something happened */
606 error = EINVAL;
607 }
608 } else if (mt->valid != VM_PAGE_BITS_ALL) {
609 /*
610 * Zero-extend the requested page if necessary (if
611 * the filesystem is using a small block size).
612 */
613 vm_page_zero_invalid(mt, TRUE);
614 }
615 }
616 if (error) {
617 kprintf("vnode_pager_getpage: I/O read error\n");
618 }
619 return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
620 }
621
622 /*
623 * EOPNOTSUPP is no longer legal. For local media VFS's that do not
624 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
625 * vnode_pager_generic_putpages() to implement the previous behaviour.
626 *
627 * Caller has already cleared the pmap modified bits, if any.
628 *
629 * All other FS's should use the bypass to get to the local media
630 * backing vp's VOP_PUTPAGES.
631 */
632 static void
vnode_pager_putpages(vm_object_t object,vm_page_t * m,int count,int flags,int * rtvals)633 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count,
634 int flags, int *rtvals)
635 {
636 int rtval;
637 struct vnode *vp;
638 int bytes = count * PAGE_SIZE;
639
640 /*
641 * Force synchronous operation if we are extremely low on memory
642 * to prevent a low-memory deadlock. VOP operations often need to
643 * allocate more memory to initiate the I/O ( i.e. do a BMAP
644 * operation ). The swapper handles the case by limiting the amount
645 * of asynchronous I/O, but that sort of solution doesn't scale well
646 * for the vnode pager without a lot of work.
647 *
648 * Also, the backing vnode's iodone routine may not wake the pageout
649 * daemon up. This should be probably be addressed XXX.
650 */
651
652 if ((vmstats.v_free_count + vmstats.v_cache_count) <
653 vmstats.v_pageout_free_min) {
654 flags |= OBJPC_SYNC;
655 }
656
657 /*
658 * Call device-specific putpages function
659 */
660 vp = object->handle;
661 rtval = VOP_PUTPAGES(vp, m, bytes, flags, rtvals, 0);
662 if (rtval == EOPNOTSUPP) {
663 kprintf("vnode_pager: *** WARNING *** stale FS putpages\n");
664 rtval = vnode_pager_generic_putpages( vp, m, bytes, flags, rtvals);
665 }
666 }
667
668
669 /*
670 * This is now called from local media FS's to operate against their
671 * own vnodes if they fail to implement VOP_PUTPAGES.
672 *
673 * This is typically called indirectly via the pageout daemon and
674 * clustering has already typically occured, so in general we ask the
675 * underlying filesystem to write the data out asynchronously rather
676 * then delayed.
677 */
678 int
vnode_pager_generic_putpages(struct vnode * vp,vm_page_t * m,int bytecount,int flags,int * rtvals)679 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *m, int bytecount,
680 int flags, int *rtvals)
681 {
682 int i;
683 int maxsize, ncount, count;
684 vm_ooffset_t poffset;
685 struct uio auio;
686 struct iovec aiov;
687 int error;
688 int ioflags;
689
690 count = bytecount / PAGE_SIZE;
691
692 for (i = 0; i < count; i++)
693 rtvals[i] = VM_PAGER_AGAIN;
694
695 if ((int) m[0]->pindex < 0) {
696 kprintf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n",
697 (long)m[0]->pindex, m[0]->dirty);
698 rtvals[0] = VM_PAGER_BAD;
699 return VM_PAGER_BAD;
700 }
701
702 maxsize = count * PAGE_SIZE;
703 ncount = count;
704
705 poffset = IDX_TO_OFF(m[0]->pindex);
706
707 /*
708 * If the page-aligned write is larger then the actual file we
709 * have to invalidate pages occuring beyond the file EOF.
710 *
711 * If the file EOF resides in the middle of a page we still clear
712 * all of that page's dirty bits later on. If we didn't it would
713 * endlessly re-write.
714 *
715 * We do not under any circumstances truncate the valid bits, as
716 * this will screw up bogus page replacement.
717 *
718 * The caller has already read-protected the pages. The VFS must
719 * use the buffer cache to wrap the pages. The pages might not
720 * be immediately flushed by the buffer cache but once under its
721 * control the pages themselves can wind up being marked clean
722 * and their covering buffer cache buffer can be marked dirty.
723 */
724 if (poffset + maxsize > vp->v_filesize) {
725 if (poffset < vp->v_filesize) {
726 maxsize = vp->v_filesize - poffset;
727 ncount = btoc(maxsize);
728 } else {
729 maxsize = 0;
730 ncount = 0;
731 }
732 if (ncount < count) {
733 for (i = ncount; i < count; i++) {
734 rtvals[i] = VM_PAGER_BAD;
735 }
736 }
737 }
738
739 /*
740 * pageouts are already clustered, use IO_ASYNC to force a bawrite()
741 * rather then a bdwrite() to prevent paging I/O from saturating
742 * the buffer cache. Dummy-up the sequential heuristic to cause
743 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set,
744 * the system decides how to cluster.
745 */
746 ioflags = IO_VMIO;
747 if (flags & (OBJPC_SYNC | OBJPC_INVAL))
748 ioflags |= IO_SYNC;
749 else if ((flags & OBJPC_CLUSTER_OK) == 0)
750 ioflags |= IO_ASYNC;
751 ioflags |= (flags & OBJPC_INVAL) ? IO_INVAL: 0;
752 ioflags |= IO_SEQMAX << IO_SEQSHIFT;
753
754 aiov.iov_base = (caddr_t) 0;
755 aiov.iov_len = maxsize;
756 auio.uio_iov = &aiov;
757 auio.uio_iovcnt = 1;
758 auio.uio_offset = poffset;
759 auio.uio_segflg = UIO_NOCOPY;
760 auio.uio_rw = UIO_WRITE;
761 auio.uio_resid = maxsize;
762 auio.uio_td = NULL;
763 error = VOP_WRITE(vp, &auio, ioflags, proc0.p_ucred);
764 mycpu->gd_cnt.v_vnodeout++;
765 mycpu->gd_cnt.v_vnodepgsout += ncount;
766
767 if (error) {
768 krateprintf(&vbadrate,
769 "vnode_pager_putpages: I/O error %d\n", error);
770 }
771 if (auio.uio_resid) {
772 krateprintf(&vresrate,
773 "vnode_pager_putpages: residual I/O %zd at %lu\n",
774 auio.uio_resid, (u_long)m[0]->pindex);
775 }
776 if (error == 0) {
777 for (i = 0; i < ncount; i++) {
778 rtvals[i] = VM_PAGER_OK;
779 vm_page_undirty(m[i]);
780 }
781 }
782 return rtvals[0];
783 }
784
785 /*
786 * Run the chain and if the bottom-most object is a vnode-type lock the
787 * underlying vnode. A locked vnode or NULL is returned.
788 *
789 * Caller must hold the first object.
790 */
791 struct vnode *
vnode_pager_lock(vm_map_backing_t ba)792 vnode_pager_lock(vm_map_backing_t ba)
793 {
794 vm_map_backing_t lba;
795 struct vnode *vp = NULL;
796 vm_object_t lobject;
797 int error;
798
799 if (ba == NULL)
800 return NULL;
801 lba = ba;
802 while (lba->backing_ba)
803 lba = lba->backing_ba;
804 if ((lobject = lba->object) == NULL)
805 return NULL;
806 if (lba != ba)
807 vm_object_hold_shared(lobject);
808
809 while (lobject->type == OBJT_VNODE &&
810 (lobject->flags & OBJ_DEAD) == 0) {
811 /*
812 * Extract the vp
813 */
814 vp = lobject->handle;
815 error = vget(vp, LK_SHARED | LK_RETRY | LK_CANRECURSE);
816 if (error == 0) {
817 if (lobject->handle == vp)
818 break;
819 vput(vp);
820 } else {
821 kprintf("vnode_pager_lock: vp %p error %d "
822 "lockstatus %d, retrying\n",
823 vp, error,
824 lockstatus(&vp->v_lock, curthread));
825 tsleep(lobject->handle, 0, "vnpgrl", hz);
826 }
827 vp = NULL;
828 }
829 if (lba != ba)
830 vm_object_drop(lobject);
831 return (vp);
832 }
833