FreeBSD/Linux Kernel Cross Reference
sys/vm/vnode_pager.c
1 /*-
2 * Copyright (c) 1990 University of Utah.
3 * Copyright (c) 1991 The Regents of the University of California.
4 * All rights reserved.
5 * Copyright (c) 1993, 1994 John S. Dyson
6 * Copyright (c) 1995, David Greenman
7 *
8 * This code is derived from software contributed to Berkeley by
9 * the Systems Programming Group of the University of Utah Computer
10 * Science Department.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by the University of
23 * California, Berkeley and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 * may be used to endorse or promote products derived from this software
26 * without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 *
40 * from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91
41 */
42
43 /*
44 * Page to/from files (vnodes).
45 */
46
47 /*
48 * TODO:
49 * Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will
50 * greatly re-simplify the vnode_pager.
51 */
52
53 #include <sys/cdefs.h>
54 __FBSDID("$FreeBSD: releng/10.2/sys/vm/vnode_pager.c 284100 2015-06-06 20:37:40Z jhb $");
55
56 #include <sys/param.h>
57 #include <sys/systm.h>
58 #include <sys/proc.h>
59 #include <sys/vnode.h>
60 #include <sys/mount.h>
61 #include <sys/bio.h>
62 #include <sys/buf.h>
63 #include <sys/vmmeter.h>
64 #include <sys/limits.h>
65 #include <sys/conf.h>
66 #include <sys/rwlock.h>
67 #include <sys/sf_buf.h>
68
69 #include <machine/atomic.h>
70
71 #include <vm/vm.h>
72 #include <vm/vm_param.h>
73 #include <vm/vm_object.h>
74 #include <vm/vm_page.h>
75 #include <vm/vm_pager.h>
76 #include <vm/vm_map.h>
77 #include <vm/vnode_pager.h>
78 #include <vm/vm_extern.h>
79
80 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address,
81 daddr_t *rtaddress, int *run);
82 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m);
83 static int vnode_pager_input_old(vm_object_t object, vm_page_t m);
84 static void vnode_pager_dealloc(vm_object_t);
85 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int);
86 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, int, int *);
87 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
88 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
89 vm_ooffset_t, struct ucred *cred);
90
91 struct pagerops vnodepagerops = {
92 .pgo_alloc = vnode_pager_alloc,
93 .pgo_dealloc = vnode_pager_dealloc,
94 .pgo_getpages = vnode_pager_getpages,
95 .pgo_putpages = vnode_pager_putpages,
96 .pgo_haspage = vnode_pager_haspage,
97 };
98
99 int vnode_pbuf_freecnt;
100
101 /* Create the VM system backing object for this vnode */
102 int
103 vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td)
104 {
105 vm_object_t object;
106 vm_ooffset_t size = isize;
107 struct vattr va;
108
109 if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
110 return (0);
111
112 while ((object = vp->v_object) != NULL) {
113 VM_OBJECT_WLOCK(object);
114 if (!(object->flags & OBJ_DEAD)) {
115 VM_OBJECT_WUNLOCK(object);
116 return (0);
117 }
118 VOP_UNLOCK(vp, 0);
119 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
120 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vodead", 0);
121 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
122 }
123
124 if (size == 0) {
125 if (vn_isdisk(vp, NULL)) {
126 size = IDX_TO_OFF(INT_MAX);
127 } else {
128 if (VOP_GETATTR(vp, &va, td->td_ucred))
129 return (0);
130 size = va.va_size;
131 }
132 }
133
134 object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred);
135 /*
136 * Dereference the reference we just created. This assumes
137 * that the object is associated with the vp.
138 */
139 VM_OBJECT_WLOCK(object);
140 object->ref_count--;
141 VM_OBJECT_WUNLOCK(object);
142 vrele(vp);
143
144 KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object"));
145
146 return (0);
147 }
148
149 void
150 vnode_destroy_vobject(struct vnode *vp)
151 {
152 struct vm_object *obj;
153
154 obj = vp->v_object;
155 if (obj == NULL)
156 return;
157 ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject");
158 VM_OBJECT_WLOCK(obj);
159 if (obj->ref_count == 0) {
160 /*
161 * don't double-terminate the object
162 */
163 if ((obj->flags & OBJ_DEAD) == 0)
164 vm_object_terminate(obj);
165 else
166 VM_OBJECT_WUNLOCK(obj);
167 } else {
168 /*
169 * Woe to the process that tries to page now :-).
170 */
171 vm_pager_deallocate(obj);
172 VM_OBJECT_WUNLOCK(obj);
173 }
174 vp->v_object = NULL;
175 }
176
177
178 /*
179 * Allocate (or lookup) pager for a vnode.
180 * Handle is a vnode pointer.
181 *
182 * MPSAFE
183 */
184 vm_object_t
185 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
186 vm_ooffset_t offset, struct ucred *cred)
187 {
188 vm_object_t object;
189 struct vnode *vp;
190
191 /*
192 * Pageout to vnode, no can do yet.
193 */
194 if (handle == NULL)
195 return (NULL);
196
197 vp = (struct vnode *) handle;
198
199 /*
200 * If the object is being terminated, wait for it to
201 * go away.
202 */
203 retry:
204 while ((object = vp->v_object) != NULL) {
205 VM_OBJECT_WLOCK(object);
206 if ((object->flags & OBJ_DEAD) == 0)
207 break;
208 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
209 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vadead", 0);
210 }
211
212 KASSERT(vp->v_usecount != 0, ("vnode_pager_alloc: no vnode reference"));
213
214 if (object == NULL) {
215 /*
216 * Add an object of the appropriate size
217 */
218 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size)));
219
220 object->un_pager.vnp.vnp_size = size;
221 object->un_pager.vnp.writemappings = 0;
222
223 object->handle = handle;
224 VI_LOCK(vp);
225 if (vp->v_object != NULL) {
226 /*
227 * Object has been created while we were sleeping
228 */
229 VI_UNLOCK(vp);
230 VM_OBJECT_WLOCK(object);
231 KASSERT(object->ref_count == 1,
232 ("leaked ref %p %d", object, object->ref_count));
233 object->type = OBJT_DEAD;
234 object->ref_count = 0;
235 VM_OBJECT_WUNLOCK(object);
236 vm_object_destroy(object);
237 goto retry;
238 }
239 vp->v_object = object;
240 VI_UNLOCK(vp);
241 } else {
242 object->ref_count++;
243 VM_OBJECT_WUNLOCK(object);
244 }
245 vref(vp);
246 return (object);
247 }
248
249 /*
250 * The object must be locked.
251 */
252 static void
253 vnode_pager_dealloc(object)
254 vm_object_t object;
255 {
256 struct vnode *vp;
257 int refs;
258
259 vp = object->handle;
260 if (vp == NULL)
261 panic("vnode_pager_dealloc: pager already dealloced");
262
263 VM_OBJECT_ASSERT_WLOCKED(object);
264 vm_object_pip_wait(object, "vnpdea");
265 refs = object->ref_count;
266
267 object->handle = NULL;
268 object->type = OBJT_DEAD;
269 if (object->flags & OBJ_DISCONNECTWNT) {
270 vm_object_clear_flag(object, OBJ_DISCONNECTWNT);
271 wakeup(object);
272 }
273 ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc");
274 if (object->un_pager.vnp.writemappings > 0) {
275 object->un_pager.vnp.writemappings = 0;
276 VOP_ADD_WRITECOUNT(vp, -1);
277 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
278 __func__, vp, vp->v_writecount);
279 }
280 vp->v_object = NULL;
281 VOP_UNSET_TEXT(vp);
282 VM_OBJECT_WUNLOCK(object);
283 while (refs-- > 0)
284 vunref(vp);
285 VM_OBJECT_WLOCK(object);
286 }
287
288 static boolean_t
289 vnode_pager_haspage(object, pindex, before, after)
290 vm_object_t object;
291 vm_pindex_t pindex;
292 int *before;
293 int *after;
294 {
295 struct vnode *vp = object->handle;
296 daddr_t bn;
297 int err;
298 daddr_t reqblock;
299 int poff;
300 int bsize;
301 int pagesperblock, blocksperpage;
302
303 VM_OBJECT_ASSERT_WLOCKED(object);
304 /*
305 * If no vp or vp is doomed or marked transparent to VM, we do not
306 * have the page.
307 */
308 if (vp == NULL || vp->v_iflag & VI_DOOMED)
309 return FALSE;
310 /*
311 * If the offset is beyond end of file we do
312 * not have the page.
313 */
314 if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size)
315 return FALSE;
316
317 bsize = vp->v_mount->mnt_stat.f_iosize;
318 pagesperblock = bsize / PAGE_SIZE;
319 blocksperpage = 0;
320 if (pagesperblock > 0) {
321 reqblock = pindex / pagesperblock;
322 } else {
323 blocksperpage = (PAGE_SIZE / bsize);
324 reqblock = pindex * blocksperpage;
325 }
326 VM_OBJECT_WUNLOCK(object);
327 err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
328 VM_OBJECT_WLOCK(object);
329 if (err)
330 return TRUE;
331 if (bn == -1)
332 return FALSE;
333 if (pagesperblock > 0) {
334 poff = pindex - (reqblock * pagesperblock);
335 if (before) {
336 *before *= pagesperblock;
337 *before += poff;
338 }
339 if (after) {
340 int numafter;
341 *after *= pagesperblock;
342 numafter = pagesperblock - (poff + 1);
343 if (IDX_TO_OFF(pindex + numafter) >
344 object->un_pager.vnp.vnp_size) {
345 numafter =
346 OFF_TO_IDX(object->un_pager.vnp.vnp_size) -
347 pindex;
348 }
349 *after += numafter;
350 }
351 } else {
352 if (before) {
353 *before /= blocksperpage;
354 }
355
356 if (after) {
357 *after /= blocksperpage;
358 }
359 }
360 return TRUE;
361 }
362
363 /*
364 * Lets the VM system know about a change in size for a file.
365 * We adjust our own internal size and flush any cached pages in
366 * the associated object that are affected by the size change.
367 *
368 * Note: this routine may be invoked as a result of a pager put
369 * operation (possibly at object termination time), so we must be careful.
370 */
371 void
372 vnode_pager_setsize(vp, nsize)
373 struct vnode *vp;
374 vm_ooffset_t nsize;
375 {
376 vm_object_t object;
377 vm_page_t m;
378 vm_pindex_t nobjsize;
379
380 if ((object = vp->v_object) == NULL)
381 return;
382 /* ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */
383 VM_OBJECT_WLOCK(object);
384 if (object->type == OBJT_DEAD) {
385 VM_OBJECT_WUNLOCK(object);
386 return;
387 }
388 KASSERT(object->type == OBJT_VNODE,
389 ("not vnode-backed object %p", object));
390 if (nsize == object->un_pager.vnp.vnp_size) {
391 /*
392 * Hasn't changed size
393 */
394 VM_OBJECT_WUNLOCK(object);
395 return;
396 }
397 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
398 if (nsize < object->un_pager.vnp.vnp_size) {
399 /*
400 * File has shrunk. Toss any cached pages beyond the new EOF.
401 */
402 if (nobjsize < object->size)
403 vm_object_page_remove(object, nobjsize, object->size,
404 0);
405 /*
406 * this gets rid of garbage at the end of a page that is now
407 * only partially backed by the vnode.
408 *
409 * XXX for some reason (I don't know yet), if we take a
410 * completely invalid page and mark it partially valid
411 * it can screw up NFS reads, so we don't allow the case.
412 */
413 if ((nsize & PAGE_MASK) &&
414 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL &&
415 m->valid != 0) {
416 int base = (int)nsize & PAGE_MASK;
417 int size = PAGE_SIZE - base;
418
419 /*
420 * Clear out partial-page garbage in case
421 * the page has been mapped.
422 */
423 pmap_zero_page_area(m, base, size);
424
425 /*
426 * Update the valid bits to reflect the blocks that
427 * have been zeroed. Some of these valid bits may
428 * have already been set.
429 */
430 vm_page_set_valid_range(m, base, size);
431
432 /*
433 * Round "base" to the next block boundary so that the
434 * dirty bit for a partially zeroed block is not
435 * cleared.
436 */
437 base = roundup2(base, DEV_BSIZE);
438
439 /*
440 * Clear out partial-page dirty bits.
441 *
442 * note that we do not clear out the valid
443 * bits. This would prevent bogus_page
444 * replacement from working properly.
445 */
446 vm_page_clear_dirty(m, base, PAGE_SIZE - base);
447 } else if ((nsize & PAGE_MASK) &&
448 vm_page_is_cached(object, OFF_TO_IDX(nsize))) {
449 vm_page_cache_free(object, OFF_TO_IDX(nsize),
450 nobjsize);
451 }
452 }
453 object->un_pager.vnp.vnp_size = nsize;
454 object->size = nobjsize;
455 VM_OBJECT_WUNLOCK(object);
456 }
457
458 /*
459 * calculate the linear (byte) disk address of specified virtual
460 * file address
461 */
462 static int
463 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress,
464 int *run)
465 {
466 int bsize;
467 int err;
468 daddr_t vblock;
469 daddr_t voffset;
470
471 if (address < 0)
472 return -1;
473
474 if (vp->v_iflag & VI_DOOMED)
475 return -1;
476
477 bsize = vp->v_mount->mnt_stat.f_iosize;
478 vblock = address / bsize;
479 voffset = address % bsize;
480
481 err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL);
482 if (err == 0) {
483 if (*rtaddress != -1)
484 *rtaddress += voffset / DEV_BSIZE;
485 if (run) {
486 *run += 1;
487 *run *= bsize/PAGE_SIZE;
488 *run -= voffset/PAGE_SIZE;
489 }
490 }
491
492 return (err);
493 }
494
495 /*
496 * small block filesystem vnode pager input
497 */
498 static int
499 vnode_pager_input_smlfs(object, m)
500 vm_object_t object;
501 vm_page_t m;
502 {
503 struct vnode *vp;
504 struct bufobj *bo;
505 struct buf *bp;
506 struct sf_buf *sf;
507 daddr_t fileaddr;
508 vm_offset_t bsize;
509 vm_page_bits_t bits;
510 int error, i;
511
512 error = 0;
513 vp = object->handle;
514 if (vp->v_iflag & VI_DOOMED)
515 return VM_PAGER_BAD;
516
517 bsize = vp->v_mount->mnt_stat.f_iosize;
518
519 VOP_BMAP(vp, 0, &bo, 0, NULL, NULL);
520
521 sf = sf_buf_alloc(m, 0);
522
523 for (i = 0; i < PAGE_SIZE / bsize; i++) {
524 vm_ooffset_t address;
525
526 bits = vm_page_bits(i * bsize, bsize);
527 if (m->valid & bits)
528 continue;
529
530 address = IDX_TO_OFF(m->pindex) + i * bsize;
531 if (address >= object->un_pager.vnp.vnp_size) {
532 fileaddr = -1;
533 } else {
534 error = vnode_pager_addr(vp, address, &fileaddr, NULL);
535 if (error)
536 break;
537 }
538 if (fileaddr != -1) {
539 bp = getpbuf(&vnode_pbuf_freecnt);
540
541 /* build a minimal buffer header */
542 bp->b_iocmd = BIO_READ;
543 bp->b_iodone = bdone;
544 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
545 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
546 bp->b_rcred = crhold(curthread->td_ucred);
547 bp->b_wcred = crhold(curthread->td_ucred);
548 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize;
549 bp->b_blkno = fileaddr;
550 pbgetbo(bo, bp);
551 bp->b_vp = vp;
552 bp->b_bcount = bsize;
553 bp->b_bufsize = bsize;
554 bp->b_runningbufspace = bp->b_bufsize;
555 atomic_add_long(&runningbufspace, bp->b_runningbufspace);
556
557 /* do the input */
558 bp->b_iooffset = dbtob(bp->b_blkno);
559 bstrategy(bp);
560
561 bwait(bp, PVM, "vnsrd");
562
563 if ((bp->b_ioflags & BIO_ERROR) != 0)
564 error = EIO;
565
566 /*
567 * free the buffer header back to the swap buffer pool
568 */
569 bp->b_vp = NULL;
570 pbrelbo(bp);
571 relpbuf(bp, &vnode_pbuf_freecnt);
572 if (error)
573 break;
574 } else
575 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
576 KASSERT((m->dirty & bits) == 0,
577 ("vnode_pager_input_smlfs: page %p is dirty", m));
578 VM_OBJECT_WLOCK(object);
579 m->valid |= bits;
580 VM_OBJECT_WUNLOCK(object);
581 }
582 sf_buf_free(sf);
583 if (error) {
584 return VM_PAGER_ERROR;
585 }
586 return VM_PAGER_OK;
587 }
588
589 /*
590 * old style vnode pager input routine
591 */
592 static int
593 vnode_pager_input_old(object, m)
594 vm_object_t object;
595 vm_page_t m;
596 {
597 struct uio auio;
598 struct iovec aiov;
599 int error;
600 int size;
601 struct sf_buf *sf;
602 struct vnode *vp;
603
604 VM_OBJECT_ASSERT_WLOCKED(object);
605 error = 0;
606
607 /*
608 * Return failure if beyond current EOF
609 */
610 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) {
611 return VM_PAGER_BAD;
612 } else {
613 size = PAGE_SIZE;
614 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size)
615 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex);
616 vp = object->handle;
617 VM_OBJECT_WUNLOCK(object);
618
619 /*
620 * Allocate a kernel virtual address and initialize so that
621 * we can use VOP_READ/WRITE routines.
622 */
623 sf = sf_buf_alloc(m, 0);
624
625 aiov.iov_base = (caddr_t)sf_buf_kva(sf);
626 aiov.iov_len = size;
627 auio.uio_iov = &aiov;
628 auio.uio_iovcnt = 1;
629 auio.uio_offset = IDX_TO_OFF(m->pindex);
630 auio.uio_segflg = UIO_SYSSPACE;
631 auio.uio_rw = UIO_READ;
632 auio.uio_resid = size;
633 auio.uio_td = curthread;
634
635 error = VOP_READ(vp, &auio, 0, curthread->td_ucred);
636 if (!error) {
637 int count = size - auio.uio_resid;
638
639 if (count == 0)
640 error = EINVAL;
641 else if (count != PAGE_SIZE)
642 bzero((caddr_t)sf_buf_kva(sf) + count,
643 PAGE_SIZE - count);
644 }
645 sf_buf_free(sf);
646
647 VM_OBJECT_WLOCK(object);
648 }
649 KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m));
650 if (!error)
651 m->valid = VM_PAGE_BITS_ALL;
652 return error ? VM_PAGER_ERROR : VM_PAGER_OK;
653 }
654
655 /*
656 * generic vnode pager input routine
657 */
658
659 /*
660 * Local media VFS's that do not implement their own VOP_GETPAGES
661 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages()
662 * to implement the previous behaviour.
663 *
664 * All other FS's should use the bypass to get to the local media
665 * backing vp's VOP_GETPAGES.
666 */
667 static int
668 vnode_pager_getpages(object, m, count, reqpage)
669 vm_object_t object;
670 vm_page_t *m;
671 int count;
672 int reqpage;
673 {
674 int rtval;
675 struct vnode *vp;
676 int bytes = count * PAGE_SIZE;
677
678 vp = object->handle;
679 VM_OBJECT_WUNLOCK(object);
680 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0);
681 KASSERT(rtval != EOPNOTSUPP,
682 ("vnode_pager: FS getpages not implemented\n"));
683 VM_OBJECT_WLOCK(object);
684 return rtval;
685 }
686
687 /*
688 * This is now called from local media FS's to operate against their
689 * own vnodes if they fail to implement VOP_GETPAGES.
690 */
691 int
692 vnode_pager_generic_getpages(vp, m, bytecount, reqpage)
693 struct vnode *vp;
694 vm_page_t *m;
695 int bytecount;
696 int reqpage;
697 {
698 vm_object_t object;
699 vm_offset_t kva;
700 off_t foff, tfoff, nextoff;
701 int i, j, size, bsize, first;
702 daddr_t firstaddr, reqblock;
703 struct bufobj *bo;
704 int runpg;
705 int runend;
706 struct buf *bp;
707 struct mount *mp;
708 int count;
709 int error;
710
711 object = vp->v_object;
712 count = bytecount / PAGE_SIZE;
713
714 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
715 ("vnode_pager_generic_getpages does not support devices"));
716 if (vp->v_iflag & VI_DOOMED)
717 return VM_PAGER_BAD;
718
719 bsize = vp->v_mount->mnt_stat.f_iosize;
720
721 /* get the UNDERLYING device for the file with VOP_BMAP() */
722
723 /*
724 * originally, we did not check for an error return value -- assuming
725 * an fs always has a bmap entry point -- that assumption is wrong!!!
726 */
727 foff = IDX_TO_OFF(m[reqpage]->pindex);
728
729 /*
730 * if we can't bmap, use old VOP code
731 */
732 error = VOP_BMAP(vp, foff / bsize, &bo, &reqblock, NULL, NULL);
733 if (error == EOPNOTSUPP) {
734 VM_OBJECT_WLOCK(object);
735
736 for (i = 0; i < count; i++)
737 if (i != reqpage) {
738 vm_page_lock(m[i]);
739 vm_page_free(m[i]);
740 vm_page_unlock(m[i]);
741 }
742 PCPU_INC(cnt.v_vnodein);
743 PCPU_INC(cnt.v_vnodepgsin);
744 error = vnode_pager_input_old(object, m[reqpage]);
745 VM_OBJECT_WUNLOCK(object);
746 return (error);
747 } else if (error != 0) {
748 VM_OBJECT_WLOCK(object);
749 for (i = 0; i < count; i++)
750 if (i != reqpage) {
751 vm_page_lock(m[i]);
752 vm_page_free(m[i]);
753 vm_page_unlock(m[i]);
754 }
755 VM_OBJECT_WUNLOCK(object);
756 return (VM_PAGER_ERROR);
757
758 /*
759 * if the blocksize is smaller than a page size, then use
760 * special small filesystem code. NFS sometimes has a small
761 * blocksize, but it can handle large reads itself.
762 */
763 } else if ((PAGE_SIZE / bsize) > 1 &&
764 (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) {
765 VM_OBJECT_WLOCK(object);
766 for (i = 0; i < count; i++)
767 if (i != reqpage) {
768 vm_page_lock(m[i]);
769 vm_page_free(m[i]);
770 vm_page_unlock(m[i]);
771 }
772 VM_OBJECT_WUNLOCK(object);
773 PCPU_INC(cnt.v_vnodein);
774 PCPU_INC(cnt.v_vnodepgsin);
775 return vnode_pager_input_smlfs(object, m[reqpage]);
776 }
777
778 /*
779 * If we have a completely valid page available to us, we can
780 * clean up and return. Otherwise we have to re-read the
781 * media.
782 */
783 VM_OBJECT_WLOCK(object);
784 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) {
785 for (i = 0; i < count; i++)
786 if (i != reqpage) {
787 vm_page_lock(m[i]);
788 vm_page_free(m[i]);
789 vm_page_unlock(m[i]);
790 }
791 VM_OBJECT_WUNLOCK(object);
792 return VM_PAGER_OK;
793 } else if (reqblock == -1) {
794 pmap_zero_page(m[reqpage]);
795 KASSERT(m[reqpage]->dirty == 0,
796 ("vnode_pager_generic_getpages: page %p is dirty", m));
797 m[reqpage]->valid = VM_PAGE_BITS_ALL;
798 for (i = 0; i < count; i++)
799 if (i != reqpage) {
800 vm_page_lock(m[i]);
801 vm_page_free(m[i]);
802 vm_page_unlock(m[i]);
803 }
804 VM_OBJECT_WUNLOCK(object);
805 return (VM_PAGER_OK);
806 }
807 m[reqpage]->valid = 0;
808 VM_OBJECT_WUNLOCK(object);
809
810 /*
811 * here on direct device I/O
812 */
813 firstaddr = -1;
814
815 /*
816 * calculate the run that includes the required page
817 */
818 for (first = 0, i = 0; i < count; i = runend) {
819 if (vnode_pager_addr(vp, IDX_TO_OFF(m[i]->pindex), &firstaddr,
820 &runpg) != 0) {
821 VM_OBJECT_WLOCK(object);
822 for (; i < count; i++)
823 if (i != reqpage) {
824 vm_page_lock(m[i]);
825 vm_page_free(m[i]);
826 vm_page_unlock(m[i]);
827 }
828 VM_OBJECT_WUNLOCK(object);
829 return (VM_PAGER_ERROR);
830 }
831 if (firstaddr == -1) {
832 VM_OBJECT_WLOCK(object);
833 if (i == reqpage && foff < object->un_pager.vnp.vnp_size) {
834 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx",
835 (intmax_t)firstaddr, (uintmax_t)(foff >> 32),
836 (uintmax_t)foff,
837 (uintmax_t)
838 (object->un_pager.vnp.vnp_size >> 32),
839 (uintmax_t)object->un_pager.vnp.vnp_size);
840 }
841 vm_page_lock(m[i]);
842 vm_page_free(m[i]);
843 vm_page_unlock(m[i]);
844 VM_OBJECT_WUNLOCK(object);
845 runend = i + 1;
846 first = runend;
847 continue;
848 }
849 runend = i + runpg;
850 if (runend <= reqpage) {
851 VM_OBJECT_WLOCK(object);
852 for (j = i; j < runend; j++) {
853 vm_page_lock(m[j]);
854 vm_page_free(m[j]);
855 vm_page_unlock(m[j]);
856 }
857 VM_OBJECT_WUNLOCK(object);
858 } else {
859 if (runpg < (count - first)) {
860 VM_OBJECT_WLOCK(object);
861 for (i = first + runpg; i < count; i++) {
862 vm_page_lock(m[i]);
863 vm_page_free(m[i]);
864 vm_page_unlock(m[i]);
865 }
866 VM_OBJECT_WUNLOCK(object);
867 count = first + runpg;
868 }
869 break;
870 }
871 first = runend;
872 }
873
874 /*
875 * the first and last page have been calculated now, move input pages
876 * to be zero based...
877 */
878 if (first != 0) {
879 m += first;
880 count -= first;
881 reqpage -= first;
882 }
883
884 /*
885 * calculate the file virtual address for the transfer
886 */
887 foff = IDX_TO_OFF(m[0]->pindex);
888
889 /*
890 * calculate the size of the transfer
891 */
892 size = count * PAGE_SIZE;
893 KASSERT(count > 0, ("zero count"));
894 if ((foff + size) > object->un_pager.vnp.vnp_size)
895 size = object->un_pager.vnp.vnp_size - foff;
896 KASSERT(size > 0, ("zero size"));
897
898 /*
899 * round up physical size for real devices.
900 */
901 if (1) {
902 int secmask = bo->bo_bsize - 1;
903 KASSERT(secmask < PAGE_SIZE && secmask > 0,
904 ("vnode_pager_generic_getpages: sector size %d too large",
905 secmask + 1));
906 size = (size + secmask) & ~secmask;
907 }
908
909 bp = getpbuf(&vnode_pbuf_freecnt);
910 kva = (vm_offset_t)bp->b_data;
911
912 /*
913 * and map the pages to be read into the kva, if the filesystem
914 * requires mapped buffers.
915 */
916 mp = vp->v_mount;
917 if (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 &&
918 unmapped_buf_allowed) {
919 bp->b_data = unmapped_buf;
920 bp->b_kvabase = unmapped_buf;
921 bp->b_offset = 0;
922 bp->b_flags |= B_UNMAPPED;
923 bp->b_npages = count;
924 for (i = 0; i < count; i++)
925 bp->b_pages[i] = m[i];
926 } else
927 pmap_qenter(kva, m, count);
928
929 /* build a minimal buffer header */
930 bp->b_iocmd = BIO_READ;
931 bp->b_iodone = bdone;
932 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
933 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
934 bp->b_rcred = crhold(curthread->td_ucred);
935 bp->b_wcred = crhold(curthread->td_ucred);
936 bp->b_blkno = firstaddr;
937 pbgetbo(bo, bp);
938 bp->b_vp = vp;
939 bp->b_bcount = size;
940 bp->b_bufsize = size;
941 bp->b_runningbufspace = bp->b_bufsize;
942 atomic_add_long(&runningbufspace, bp->b_runningbufspace);
943
944 PCPU_INC(cnt.v_vnodein);
945 PCPU_ADD(cnt.v_vnodepgsin, count);
946
947 /* do the input */
948 bp->b_iooffset = dbtob(bp->b_blkno);
949 bstrategy(bp);
950
951 bwait(bp, PVM, "vnread");
952
953 if ((bp->b_ioflags & BIO_ERROR) != 0)
954 error = EIO;
955
956 if (error == 0 && size != count * PAGE_SIZE) {
957 if ((bp->b_flags & B_UNMAPPED) != 0) {
958 bp->b_flags &= ~B_UNMAPPED;
959 pmap_qenter(kva, m, count);
960 }
961 bzero((caddr_t)kva + size, PAGE_SIZE * count - size);
962 }
963 if ((bp->b_flags & B_UNMAPPED) == 0)
964 pmap_qremove(kva, count);
965 if (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0) {
966 bp->b_data = (caddr_t)kva;
967 bp->b_kvabase = (caddr_t)kva;
968 bp->b_flags &= ~B_UNMAPPED;
969 for (i = 0; i < count; i++)
970 bp->b_pages[i] = NULL;
971 }
972
973 /*
974 * free the buffer header back to the swap buffer pool
975 */
976 bp->b_vp = NULL;
977 pbrelbo(bp);
978 relpbuf(bp, &vnode_pbuf_freecnt);
979
980 VM_OBJECT_WLOCK(object);
981 for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) {
982 vm_page_t mt;
983
984 nextoff = tfoff + PAGE_SIZE;
985 mt = m[i];
986
987 if (nextoff <= object->un_pager.vnp.vnp_size) {
988 /*
989 * Read filled up entire page.
990 */
991 mt->valid = VM_PAGE_BITS_ALL;
992 KASSERT(mt->dirty == 0,
993 ("vnode_pager_generic_getpages: page %p is dirty",
994 mt));
995 KASSERT(!pmap_page_is_mapped(mt),
996 ("vnode_pager_generic_getpages: page %p is mapped",
997 mt));
998 } else {
999 /*
1000 * Read did not fill up entire page.
1001 *
1002 * Currently we do not set the entire page valid,
1003 * we just try to clear the piece that we couldn't
1004 * read.
1005 */
1006 vm_page_set_valid_range(mt, 0,
1007 object->un_pager.vnp.vnp_size - tfoff);
1008 KASSERT((mt->dirty & vm_page_bits(0,
1009 object->un_pager.vnp.vnp_size - tfoff)) == 0,
1010 ("vnode_pager_generic_getpages: page %p is dirty",
1011 mt));
1012 }
1013
1014 if (i != reqpage)
1015 vm_page_readahead_finish(mt);
1016 }
1017 VM_OBJECT_WUNLOCK(object);
1018 if (error) {
1019 printf("vnode_pager_getpages: I/O read error\n");
1020 }
1021 return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
1022 }
1023
1024 /*
1025 * EOPNOTSUPP is no longer legal. For local media VFS's that do not
1026 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
1027 * vnode_pager_generic_putpages() to implement the previous behaviour.
1028 *
1029 * All other FS's should use the bypass to get to the local media
1030 * backing vp's VOP_PUTPAGES.
1031 */
1032 static void
1033 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count,
1034 int flags, int *rtvals)
1035 {
1036 int rtval;
1037 struct vnode *vp;
1038 int bytes = count * PAGE_SIZE;
1039
1040 /*
1041 * Force synchronous operation if we are extremely low on memory
1042 * to prevent a low-memory deadlock. VOP operations often need to
1043 * allocate more memory to initiate the I/O ( i.e. do a BMAP
1044 * operation ). The swapper handles the case by limiting the amount
1045 * of asynchronous I/O, but that sort of solution doesn't scale well
1046 * for the vnode pager without a lot of work.
1047 *
1048 * Also, the backing vnode's iodone routine may not wake the pageout
1049 * daemon up. This should be probably be addressed XXX.
1050 */
1051
1052 if (cnt.v_free_count + cnt.v_cache_count < cnt.v_pageout_free_min)
1053 flags |= VM_PAGER_PUT_SYNC;
1054
1055 /*
1056 * Call device-specific putpages function
1057 */
1058 vp = object->handle;
1059 VM_OBJECT_WUNLOCK(object);
1060 rtval = VOP_PUTPAGES(vp, m, bytes, flags, rtvals, 0);
1061 KASSERT(rtval != EOPNOTSUPP,
1062 ("vnode_pager: stale FS putpages\n"));
1063 VM_OBJECT_WLOCK(object);
1064 }
1065
1066
1067 /*
1068 * This is now called from local media FS's to operate against their
1069 * own vnodes if they fail to implement VOP_PUTPAGES.
1070 *
1071 * This is typically called indirectly via the pageout daemon and
1072 * clustering has already typically occured, so in general we ask the
1073 * underlying filesystem to write the data out asynchronously rather
1074 * then delayed.
1075 */
1076 int
1077 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount,
1078 int flags, int *rtvals)
1079 {
1080 int i;
1081 vm_object_t object;
1082 vm_page_t m;
1083 int count;
1084
1085 int maxsize, ncount;
1086 vm_ooffset_t poffset;
1087 struct uio auio;
1088 struct iovec aiov;
1089 int error;
1090 int ioflags;
1091 int ppscheck = 0;
1092 static struct timeval lastfail;
1093 static int curfail;
1094
1095 object = vp->v_object;
1096 count = bytecount / PAGE_SIZE;
1097
1098 for (i = 0; i < count; i++)
1099 rtvals[i] = VM_PAGER_ERROR;
1100
1101 if ((int64_t)ma[0]->pindex < 0) {
1102 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n",
1103 (long)ma[0]->pindex, (u_long)ma[0]->dirty);
1104 rtvals[0] = VM_PAGER_BAD;
1105 return VM_PAGER_BAD;
1106 }
1107
1108 maxsize = count * PAGE_SIZE;
1109 ncount = count;
1110
1111 poffset = IDX_TO_OFF(ma[0]->pindex);
1112
1113 /*
1114 * If the page-aligned write is larger then the actual file we
1115 * have to invalidate pages occuring beyond the file EOF. However,
1116 * there is an edge case where a file may not be page-aligned where
1117 * the last page is partially invalid. In this case the filesystem
1118 * may not properly clear the dirty bits for the entire page (which
1119 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d).
1120 * With the page locked we are free to fix-up the dirty bits here.
1121 *
1122 * We do not under any circumstances truncate the valid bits, as
1123 * this will screw up bogus page replacement.
1124 */
1125 VM_OBJECT_WLOCK(object);
1126 if (maxsize + poffset > object->un_pager.vnp.vnp_size) {
1127 if (object->un_pager.vnp.vnp_size > poffset) {
1128 int pgoff;
1129
1130 maxsize = object->un_pager.vnp.vnp_size - poffset;
1131 ncount = btoc(maxsize);
1132 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) {
1133 /*
1134 * If the object is locked and the following
1135 * conditions hold, then the page's dirty
1136 * field cannot be concurrently changed by a
1137 * pmap operation.
1138 */
1139 m = ma[ncount - 1];
1140 vm_page_assert_sbusied(m);
1141 KASSERT(!pmap_page_is_write_mapped(m),
1142 ("vnode_pager_generic_putpages: page %p is not read-only", m));
1143 vm_page_clear_dirty(m, pgoff, PAGE_SIZE -
1144 pgoff);
1145 }
1146 } else {
1147 maxsize = 0;
1148 ncount = 0;
1149 }
1150 if (ncount < count) {
1151 for (i = ncount; i < count; i++) {
1152 rtvals[i] = VM_PAGER_BAD;
1153 }
1154 }
1155 }
1156 VM_OBJECT_WUNLOCK(object);
1157
1158 /*
1159 * pageouts are already clustered, use IO_ASYNC to force a bawrite()
1160 * rather then a bdwrite() to prevent paging I/O from saturating
1161 * the buffer cache. Dummy-up the sequential heuristic to cause
1162 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set,
1163 * the system decides how to cluster.
1164 */
1165 ioflags = IO_VMIO;
1166 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL))
1167 ioflags |= IO_SYNC;
1168 else if ((flags & VM_PAGER_CLUSTER_OK) == 0)
1169 ioflags |= IO_ASYNC;
1170 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0;
1171 ioflags |= IO_SEQMAX << IO_SEQSHIFT;
1172
1173 aiov.iov_base = (caddr_t) 0;
1174 aiov.iov_len = maxsize;
1175 auio.uio_iov = &aiov;
1176 auio.uio_iovcnt = 1;
1177 auio.uio_offset = poffset;
1178 auio.uio_segflg = UIO_NOCOPY;
1179 auio.uio_rw = UIO_WRITE;
1180 auio.uio_resid = maxsize;
1181 auio.uio_td = (struct thread *) 0;
1182 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred);
1183 PCPU_INC(cnt.v_vnodeout);
1184 PCPU_ADD(cnt.v_vnodepgsout, ncount);
1185
1186 if (error) {
1187 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1)))
1188 printf("vnode_pager_putpages: I/O error %d\n", error);
1189 }
1190 if (auio.uio_resid) {
1191 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1))
1192 printf("vnode_pager_putpages: residual I/O %zd at %lu\n",
1193 auio.uio_resid, (u_long)ma[0]->pindex);
1194 }
1195 for (i = 0; i < ncount; i++) {
1196 rtvals[i] = VM_PAGER_OK;
1197 }
1198 return rtvals[0];
1199 }
1200
1201 void
1202 vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written)
1203 {
1204 vm_object_t obj;
1205 int i, pos;
1206
1207 if (written == 0)
1208 return;
1209 obj = ma[0]->object;
1210 VM_OBJECT_WLOCK(obj);
1211 for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) {
1212 if (pos < trunc_page(written)) {
1213 rtvals[i] = VM_PAGER_OK;
1214 vm_page_undirty(ma[i]);
1215 } else {
1216 /* Partially written page. */
1217 rtvals[i] = VM_PAGER_AGAIN;
1218 vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK);
1219 }
1220 }
1221 VM_OBJECT_WUNLOCK(obj);
1222 }
1223
1224 void
1225 vnode_pager_update_writecount(vm_object_t object, vm_offset_t start,
1226 vm_offset_t end)
1227 {
1228 struct vnode *vp;
1229 vm_ooffset_t old_wm;
1230
1231 VM_OBJECT_WLOCK(object);
1232 if (object->type != OBJT_VNODE) {
1233 VM_OBJECT_WUNLOCK(object);
1234 return;
1235 }
1236 old_wm = object->un_pager.vnp.writemappings;
1237 object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start;
1238 vp = object->handle;
1239 if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) {
1240 ASSERT_VOP_ELOCKED(vp, "v_writecount inc");
1241 VOP_ADD_WRITECOUNT(vp, 1);
1242 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d",
1243 __func__, vp, vp->v_writecount);
1244 } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) {
1245 ASSERT_VOP_ELOCKED(vp, "v_writecount dec");
1246 VOP_ADD_WRITECOUNT(vp, -1);
1247 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
1248 __func__, vp, vp->v_writecount);
1249 }
1250 VM_OBJECT_WUNLOCK(object);
1251 }
1252
1253 void
1254 vnode_pager_release_writecount(vm_object_t object, vm_offset_t start,
1255 vm_offset_t end)
1256 {
1257 struct vnode *vp;
1258 struct mount *mp;
1259 vm_offset_t inc;
1260
1261 VM_OBJECT_WLOCK(object);
1262
1263 /*
1264 * First, recheck the object type to account for the race when
1265 * the vnode is reclaimed.
1266 */
1267 if (object->type != OBJT_VNODE) {
1268 VM_OBJECT_WUNLOCK(object);
1269 return;
1270 }
1271
1272 /*
1273 * Optimize for the case when writemappings is not going to
1274 * zero.
1275 */
1276 inc = end - start;
1277 if (object->un_pager.vnp.writemappings != inc) {
1278 object->un_pager.vnp.writemappings -= inc;
1279 VM_OBJECT_WUNLOCK(object);
1280 return;
1281 }
1282
1283 vp = object->handle;
1284 vhold(vp);
1285 VM_OBJECT_WUNLOCK(object);
1286 mp = NULL;
1287 vn_start_write(vp, &mp, V_WAIT);
1288 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1289
1290 /*
1291 * Decrement the object's writemappings, by swapping the start
1292 * and end arguments for vnode_pager_update_writecount(). If
1293 * there was not a race with vnode reclaimation, then the
1294 * vnode's v_writecount is decremented.
1295 */
1296 vnode_pager_update_writecount(object, end, start);
1297 VOP_UNLOCK(vp, 0);
1298 vdrop(vp);
1299 if (mp != NULL)
1300 vn_finished_write(mp);
1301 }
Cache object: 90027c70f16e35cfcc8cbc3295d4736d
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