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/9.2/sys/vm/vnode_pager.c 251897 2013-06-18 05:21:40Z scottl $");
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/sf_buf.h>
67
68 #include <machine/atomic.h>
69
70 #include <vm/vm.h>
71 #include <vm/vm_param.h>
72 #include <vm/vm_object.h>
73 #include <vm/vm_page.h>
74 #include <vm/vm_pager.h>
75 #include <vm/vm_map.h>
76 #include <vm/vnode_pager.h>
77 #include <vm/vm_extern.h>
78
79 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address,
80 daddr_t *rtaddress, int *run);
81 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m);
82 static int vnode_pager_input_old(vm_object_t object, vm_page_t m);
83 static void vnode_pager_dealloc(vm_object_t);
84 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int);
85 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *);
86 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
87 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
88 vm_ooffset_t, struct ucred *cred);
89
90 struct pagerops vnodepagerops = {
91 .pgo_alloc = vnode_pager_alloc,
92 .pgo_dealloc = vnode_pager_dealloc,
93 .pgo_getpages = vnode_pager_getpages,
94 .pgo_putpages = vnode_pager_putpages,
95 .pgo_haspage = vnode_pager_haspage,
96 };
97
98 int vnode_pbuf_freecnt;
99
100 /* Create the VM system backing object for this vnode */
101 int
102 vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td)
103 {
104 vm_object_t object;
105 vm_ooffset_t size = isize;
106 struct vattr va;
107
108 if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
109 return (0);
110
111 while ((object = vp->v_object) != NULL) {
112 VM_OBJECT_LOCK(object);
113 if (!(object->flags & OBJ_DEAD)) {
114 VM_OBJECT_UNLOCK(object);
115 return (0);
116 }
117 VOP_UNLOCK(vp, 0);
118 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
119 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vodead", 0);
120 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
121 }
122
123 if (size == 0) {
124 if (vn_isdisk(vp, NULL)) {
125 size = IDX_TO_OFF(INT_MAX);
126 } else {
127 if (VOP_GETATTR(vp, &va, td->td_ucred))
128 return (0);
129 size = va.va_size;
130 }
131 }
132
133 object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred);
134 /*
135 * Dereference the reference we just created. This assumes
136 * that the object is associated with the vp.
137 */
138 VM_OBJECT_LOCK(object);
139 object->ref_count--;
140 VM_OBJECT_UNLOCK(object);
141 vrele(vp);
142
143 KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object"));
144
145 return (0);
146 }
147
148 void
149 vnode_destroy_vobject(struct vnode *vp)
150 {
151 struct vm_object *obj;
152
153 obj = vp->v_object;
154 if (obj == NULL)
155 return;
156 ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject");
157 VM_OBJECT_LOCK(obj);
158 if (obj->ref_count == 0) {
159 /*
160 * vclean() may be called twice. The first time
161 * removes the primary reference to the object,
162 * the second time goes one further and is a
163 * special-case to terminate the object.
164 *
165 * don't double-terminate the object
166 */
167 if ((obj->flags & OBJ_DEAD) == 0)
168 vm_object_terminate(obj);
169 else
170 VM_OBJECT_UNLOCK(obj);
171 } else {
172 /*
173 * Woe to the process that tries to page now :-).
174 */
175 vm_pager_deallocate(obj);
176 VM_OBJECT_UNLOCK(obj);
177 }
178 vp->v_object = NULL;
179 }
180
181
182 /*
183 * Allocate (or lookup) pager for a vnode.
184 * Handle is a vnode pointer.
185 *
186 * MPSAFE
187 */
188 vm_object_t
189 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
190 vm_ooffset_t offset, struct ucred *cred)
191 {
192 vm_object_t object;
193 struct vnode *vp;
194
195 /*
196 * Pageout to vnode, no can do yet.
197 */
198 if (handle == NULL)
199 return (NULL);
200
201 vp = (struct vnode *) handle;
202
203 /*
204 * If the object is being terminated, wait for it to
205 * go away.
206 */
207 retry:
208 while ((object = vp->v_object) != NULL) {
209 VM_OBJECT_LOCK(object);
210 if ((object->flags & OBJ_DEAD) == 0)
211 break;
212 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
213 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vadead", 0);
214 }
215
216 KASSERT(vp->v_usecount != 0, ("vnode_pager_alloc: no vnode reference"));
217
218 if (object == NULL) {
219 /*
220 * Add an object of the appropriate size
221 */
222 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size)));
223
224 object->un_pager.vnp.vnp_size = size;
225 object->un_pager.vnp.writemappings = 0;
226
227 object->handle = handle;
228 VI_LOCK(vp);
229 if (vp->v_object != NULL) {
230 /*
231 * Object has been created while we were sleeping
232 */
233 VI_UNLOCK(vp);
234 vm_object_destroy(object);
235 goto retry;
236 }
237 vp->v_object = object;
238 VI_UNLOCK(vp);
239 } else {
240 object->ref_count++;
241 VM_OBJECT_UNLOCK(object);
242 }
243 vref(vp);
244 return (object);
245 }
246
247 /*
248 * The object must be locked.
249 */
250 static void
251 vnode_pager_dealloc(object)
252 vm_object_t object;
253 {
254 struct vnode *vp;
255 int refs;
256
257 vp = object->handle;
258 if (vp == NULL)
259 panic("vnode_pager_dealloc: pager already dealloced");
260
261 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
262 vm_object_pip_wait(object, "vnpdea");
263 refs = object->ref_count;
264
265 object->handle = NULL;
266 object->type = OBJT_DEAD;
267 if (object->flags & OBJ_DISCONNECTWNT) {
268 vm_object_clear_flag(object, OBJ_DISCONNECTWNT);
269 wakeup(object);
270 }
271 ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc");
272 if (object->un_pager.vnp.writemappings > 0) {
273 object->un_pager.vnp.writemappings = 0;
274 VOP_ADD_WRITECOUNT(vp, -1);
275 }
276 vp->v_object = NULL;
277 VOP_UNSET_TEXT(vp);
278 VM_OBJECT_UNLOCK(object);
279 while (refs-- > 0)
280 vunref(vp);
281 VM_OBJECT_LOCK(object);
282 }
283
284 static boolean_t
285 vnode_pager_haspage(object, pindex, before, after)
286 vm_object_t object;
287 vm_pindex_t pindex;
288 int *before;
289 int *after;
290 {
291 struct vnode *vp = object->handle;
292 daddr_t bn;
293 int err;
294 daddr_t reqblock;
295 int poff;
296 int bsize;
297 int pagesperblock, blocksperpage;
298 int vfslocked;
299
300 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
301 /*
302 * If no vp or vp is doomed or marked transparent to VM, we do not
303 * have the page.
304 */
305 if (vp == NULL || vp->v_iflag & VI_DOOMED)
306 return FALSE;
307 /*
308 * If the offset is beyond end of file we do
309 * not have the page.
310 */
311 if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size)
312 return FALSE;
313
314 bsize = vp->v_mount->mnt_stat.f_iosize;
315 pagesperblock = bsize / PAGE_SIZE;
316 blocksperpage = 0;
317 if (pagesperblock > 0) {
318 reqblock = pindex / pagesperblock;
319 } else {
320 blocksperpage = (PAGE_SIZE / bsize);
321 reqblock = pindex * blocksperpage;
322 }
323 VM_OBJECT_UNLOCK(object);
324 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
325 err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
326 VFS_UNLOCK_GIANT(vfslocked);
327 VM_OBJECT_LOCK(object);
328 if (err)
329 return TRUE;
330 if (bn == -1)
331 return FALSE;
332 if (pagesperblock > 0) {
333 poff = pindex - (reqblock * pagesperblock);
334 if (before) {
335 *before *= pagesperblock;
336 *before += poff;
337 }
338 if (after) {
339 int numafter;
340 *after *= pagesperblock;
341 numafter = pagesperblock - (poff + 1);
342 if (IDX_TO_OFF(pindex + numafter) >
343 object->un_pager.vnp.vnp_size) {
344 numafter =
345 OFF_TO_IDX(object->un_pager.vnp.vnp_size) -
346 pindex;
347 }
348 *after += numafter;
349 }
350 } else {
351 if (before) {
352 *before /= blocksperpage;
353 }
354
355 if (after) {
356 *after /= blocksperpage;
357 }
358 }
359 return TRUE;
360 }
361
362 /*
363 * Lets the VM system know about a change in size for a file.
364 * We adjust our own internal size and flush any cached pages in
365 * the associated object that are affected by the size change.
366 *
367 * Note: this routine may be invoked as a result of a pager put
368 * operation (possibly at object termination time), so we must be careful.
369 */
370 void
371 vnode_pager_setsize(vp, nsize)
372 struct vnode *vp;
373 vm_ooffset_t nsize;
374 {
375 vm_object_t object;
376 vm_page_t m;
377 vm_pindex_t nobjsize;
378
379 if ((object = vp->v_object) == NULL)
380 return;
381 /* ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */
382 VM_OBJECT_LOCK(object);
383 if (object->type == OBJT_DEAD) {
384 VM_OBJECT_UNLOCK(object);
385 return;
386 }
387 KASSERT(object->type == OBJT_VNODE,
388 ("not vnode-backed object %p", object));
389 if (nsize == object->un_pager.vnp.vnp_size) {
390 /*
391 * Hasn't changed size
392 */
393 VM_OBJECT_UNLOCK(object);
394 return;
395 }
396 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
397 if (nsize < object->un_pager.vnp.vnp_size) {
398 /*
399 * File has shrunk. Toss any cached pages beyond the new EOF.
400 */
401 if (nobjsize < object->size)
402 vm_object_page_remove(object, nobjsize, object->size,
403 0);
404 /*
405 * this gets rid of garbage at the end of a page that is now
406 * only partially backed by the vnode.
407 *
408 * XXX for some reason (I don't know yet), if we take a
409 * completely invalid page and mark it partially valid
410 * it can screw up NFS reads, so we don't allow the case.
411 */
412 if ((nsize & PAGE_MASK) &&
413 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL &&
414 m->valid != 0) {
415 int base = (int)nsize & PAGE_MASK;
416 int size = PAGE_SIZE - base;
417
418 /*
419 * Clear out partial-page garbage in case
420 * the page has been mapped.
421 */
422 pmap_zero_page_area(m, base, size);
423
424 /*
425 * Update the valid bits to reflect the blocks that
426 * have been zeroed. Some of these valid bits may
427 * have already been set.
428 */
429 vm_page_set_valid(m, base, size);
430
431 /*
432 * Round "base" to the next block boundary so that the
433 * dirty bit for a partially zeroed block is not
434 * cleared.
435 */
436 base = roundup2(base, DEV_BSIZE);
437
438 /*
439 * Clear out partial-page dirty bits.
440 *
441 * note that we do not clear out the valid
442 * bits. This would prevent bogus_page
443 * replacement from working properly.
444 */
445 vm_page_clear_dirty(m, base, PAGE_SIZE - base);
446 } else if ((nsize & PAGE_MASK) &&
447 __predict_false(object->cache != NULL)) {
448 vm_page_cache_free(object, OFF_TO_IDX(nsize),
449 nobjsize);
450 }
451 }
452 object->un_pager.vnp.vnp_size = nsize;
453 object->size = nobjsize;
454 VM_OBJECT_UNLOCK(object);
455 }
456
457 /*
458 * calculate the linear (byte) disk address of specified virtual
459 * file address
460 */
461 static int
462 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress,
463 int *run)
464 {
465 int bsize;
466 int err;
467 daddr_t vblock;
468 daddr_t voffset;
469
470 if (address < 0)
471 return -1;
472
473 if (vp->v_iflag & VI_DOOMED)
474 return -1;
475
476 bsize = vp->v_mount->mnt_stat.f_iosize;
477 vblock = address / bsize;
478 voffset = address % bsize;
479
480 err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL);
481 if (err == 0) {
482 if (*rtaddress != -1)
483 *rtaddress += voffset / DEV_BSIZE;
484 if (run) {
485 *run += 1;
486 *run *= bsize/PAGE_SIZE;
487 *run -= voffset/PAGE_SIZE;
488 }
489 }
490
491 return (err);
492 }
493
494 /*
495 * small block filesystem vnode pager input
496 */
497 static int
498 vnode_pager_input_smlfs(object, m)
499 vm_object_t object;
500 vm_page_t m;
501 {
502 struct vnode *vp;
503 struct bufobj *bo;
504 struct buf *bp;
505 struct sf_buf *sf;
506 daddr_t fileaddr;
507 vm_offset_t bsize;
508 vm_page_bits_t bits;
509 int error, i;
510
511 error = 0;
512 vp = object->handle;
513 if (vp->v_iflag & VI_DOOMED)
514 return VM_PAGER_BAD;
515
516 bsize = vp->v_mount->mnt_stat.f_iosize;
517
518 VOP_BMAP(vp, 0, &bo, 0, NULL, NULL);
519
520 sf = sf_buf_alloc(m, 0);
521
522 for (i = 0; i < PAGE_SIZE / bsize; i++) {
523 vm_ooffset_t address;
524
525 bits = vm_page_bits(i * bsize, bsize);
526 if (m->valid & bits)
527 continue;
528
529 address = IDX_TO_OFF(m->pindex) + i * bsize;
530 if (address >= object->un_pager.vnp.vnp_size) {
531 fileaddr = -1;
532 } else {
533 error = vnode_pager_addr(vp, address, &fileaddr, NULL);
534 if (error)
535 break;
536 }
537 if (fileaddr != -1) {
538 bp = getpbuf(&vnode_pbuf_freecnt);
539
540 /* build a minimal buffer header */
541 bp->b_iocmd = BIO_READ;
542 bp->b_iodone = bdone;
543 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
544 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
545 bp->b_rcred = crhold(curthread->td_ucred);
546 bp->b_wcred = crhold(curthread->td_ucred);
547 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize;
548 bp->b_blkno = fileaddr;
549 pbgetbo(bo, bp);
550 bp->b_vp = vp;
551 bp->b_bcount = bsize;
552 bp->b_bufsize = bsize;
553 bp->b_runningbufspace = bp->b_bufsize;
554 atomic_add_long(&runningbufspace, bp->b_runningbufspace);
555
556 /* do the input */
557 bp->b_iooffset = dbtob(bp->b_blkno);
558 bstrategy(bp);
559
560 bwait(bp, PVM, "vnsrd");
561
562 if ((bp->b_ioflags & BIO_ERROR) != 0)
563 error = EIO;
564
565 /*
566 * free the buffer header back to the swap buffer pool
567 */
568 bp->b_vp = NULL;
569 pbrelbo(bp);
570 relpbuf(bp, &vnode_pbuf_freecnt);
571 if (error)
572 break;
573 } else
574 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
575 KASSERT((m->dirty & bits) == 0,
576 ("vnode_pager_input_smlfs: page %p is dirty", m));
577 VM_OBJECT_LOCK(object);
578 m->valid |= bits;
579 VM_OBJECT_UNLOCK(object);
580 }
581 sf_buf_free(sf);
582 if (error) {
583 return VM_PAGER_ERROR;
584 }
585 return VM_PAGER_OK;
586 }
587
588 /*
589 * old style vnode pager input routine
590 */
591 static int
592 vnode_pager_input_old(object, m)
593 vm_object_t object;
594 vm_page_t m;
595 {
596 struct uio auio;
597 struct iovec aiov;
598 int error;
599 int size;
600 struct sf_buf *sf;
601 struct vnode *vp;
602
603 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
604 error = 0;
605
606 /*
607 * Return failure if beyond current EOF
608 */
609 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) {
610 return VM_PAGER_BAD;
611 } else {
612 size = PAGE_SIZE;
613 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size)
614 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex);
615 vp = object->handle;
616 VM_OBJECT_UNLOCK(object);
617
618 /*
619 * Allocate a kernel virtual address and initialize so that
620 * we can use VOP_READ/WRITE routines.
621 */
622 sf = sf_buf_alloc(m, 0);
623
624 aiov.iov_base = (caddr_t)sf_buf_kva(sf);
625 aiov.iov_len = size;
626 auio.uio_iov = &aiov;
627 auio.uio_iovcnt = 1;
628 auio.uio_offset = IDX_TO_OFF(m->pindex);
629 auio.uio_segflg = UIO_SYSSPACE;
630 auio.uio_rw = UIO_READ;
631 auio.uio_resid = size;
632 auio.uio_td = curthread;
633
634 error = VOP_READ(vp, &auio, 0, curthread->td_ucred);
635 if (!error) {
636 int count = size - auio.uio_resid;
637
638 if (count == 0)
639 error = EINVAL;
640 else if (count != PAGE_SIZE)
641 bzero((caddr_t)sf_buf_kva(sf) + count,
642 PAGE_SIZE - count);
643 }
644 sf_buf_free(sf);
645
646 VM_OBJECT_LOCK(object);
647 }
648 KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m));
649 if (!error)
650 m->valid = VM_PAGE_BITS_ALL;
651 return error ? VM_PAGER_ERROR : VM_PAGER_OK;
652 }
653
654 /*
655 * generic vnode pager input routine
656 */
657
658 /*
659 * Local media VFS's that do not implement their own VOP_GETPAGES
660 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages()
661 * to implement the previous behaviour.
662 *
663 * All other FS's should use the bypass to get to the local media
664 * backing vp's VOP_GETPAGES.
665 */
666 static int
667 vnode_pager_getpages(object, m, count, reqpage)
668 vm_object_t object;
669 vm_page_t *m;
670 int count;
671 int reqpage;
672 {
673 int rtval;
674 struct vnode *vp;
675 int bytes = count * PAGE_SIZE;
676 int vfslocked;
677
678 vp = object->handle;
679 VM_OBJECT_UNLOCK(object);
680 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
681 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0);
682 KASSERT(rtval != EOPNOTSUPP,
683 ("vnode_pager: FS getpages not implemented\n"));
684 VFS_UNLOCK_GIANT(vfslocked);
685 VM_OBJECT_LOCK(object);
686 return rtval;
687 }
688
689 /*
690 * This is now called from local media FS's to operate against their
691 * own vnodes if they fail to implement VOP_GETPAGES.
692 */
693 int
694 vnode_pager_generic_getpages(vp, m, bytecount, reqpage)
695 struct vnode *vp;
696 vm_page_t *m;
697 int bytecount;
698 int reqpage;
699 {
700 vm_object_t object;
701 vm_offset_t kva;
702 off_t foff, tfoff, nextoff;
703 int i, j, size, bsize, first;
704 daddr_t firstaddr, reqblock;
705 struct bufobj *bo;
706 int runpg;
707 int runend;
708 struct buf *bp;
709 struct mount *mp;
710 int count;
711 int error;
712
713 object = vp->v_object;
714 count = bytecount / PAGE_SIZE;
715
716 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
717 ("vnode_pager_generic_getpages does not support devices"));
718 if (vp->v_iflag & VI_DOOMED)
719 return VM_PAGER_BAD;
720
721 bsize = vp->v_mount->mnt_stat.f_iosize;
722
723 /* get the UNDERLYING device for the file with VOP_BMAP() */
724
725 /*
726 * originally, we did not check for an error return value -- assuming
727 * an fs always has a bmap entry point -- that assumption is wrong!!!
728 */
729 foff = IDX_TO_OFF(m[reqpage]->pindex);
730
731 /*
732 * if we can't bmap, use old VOP code
733 */
734 error = VOP_BMAP(vp, foff / bsize, &bo, &reqblock, NULL, NULL);
735 if (error == EOPNOTSUPP) {
736 VM_OBJECT_LOCK(object);
737
738 for (i = 0; i < count; i++)
739 if (i != reqpage) {
740 vm_page_lock(m[i]);
741 vm_page_free(m[i]);
742 vm_page_unlock(m[i]);
743 }
744 PCPU_INC(cnt.v_vnodein);
745 PCPU_INC(cnt.v_vnodepgsin);
746 error = vnode_pager_input_old(object, m[reqpage]);
747 VM_OBJECT_UNLOCK(object);
748 return (error);
749 } else if (error != 0) {
750 VM_OBJECT_LOCK(object);
751 for (i = 0; i < count; i++)
752 if (i != reqpage) {
753 vm_page_lock(m[i]);
754 vm_page_free(m[i]);
755 vm_page_unlock(m[i]);
756 }
757 VM_OBJECT_UNLOCK(object);
758 return (VM_PAGER_ERROR);
759
760 /*
761 * if the blocksize is smaller than a page size, then use
762 * special small filesystem code. NFS sometimes has a small
763 * blocksize, but it can handle large reads itself.
764 */
765 } else if ((PAGE_SIZE / bsize) > 1 &&
766 (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) {
767 VM_OBJECT_LOCK(object);
768 for (i = 0; i < count; i++)
769 if (i != reqpage) {
770 vm_page_lock(m[i]);
771 vm_page_free(m[i]);
772 vm_page_unlock(m[i]);
773 }
774 VM_OBJECT_UNLOCK(object);
775 PCPU_INC(cnt.v_vnodein);
776 PCPU_INC(cnt.v_vnodepgsin);
777 return vnode_pager_input_smlfs(object, m[reqpage]);
778 }
779
780 /*
781 * If we have a completely valid page available to us, we can
782 * clean up and return. Otherwise we have to re-read the
783 * media.
784 */
785 VM_OBJECT_LOCK(object);
786 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) {
787 for (i = 0; i < count; i++)
788 if (i != reqpage) {
789 vm_page_lock(m[i]);
790 vm_page_free(m[i]);
791 vm_page_unlock(m[i]);
792 }
793 VM_OBJECT_UNLOCK(object);
794 return VM_PAGER_OK;
795 } else if (reqblock == -1) {
796 pmap_zero_page(m[reqpage]);
797 KASSERT(m[reqpage]->dirty == 0,
798 ("vnode_pager_generic_getpages: page %p is dirty", m));
799 m[reqpage]->valid = VM_PAGE_BITS_ALL;
800 for (i = 0; i < count; i++)
801 if (i != reqpage) {
802 vm_page_lock(m[i]);
803 vm_page_free(m[i]);
804 vm_page_unlock(m[i]);
805 }
806 VM_OBJECT_UNLOCK(object);
807 return (VM_PAGER_OK);
808 }
809 m[reqpage]->valid = 0;
810 VM_OBJECT_UNLOCK(object);
811
812 /*
813 * here on direct device I/O
814 */
815 firstaddr = -1;
816
817 /*
818 * calculate the run that includes the required page
819 */
820 for (first = 0, i = 0; i < count; i = runend) {
821 if (vnode_pager_addr(vp, IDX_TO_OFF(m[i]->pindex), &firstaddr,
822 &runpg) != 0) {
823 VM_OBJECT_LOCK(object);
824 for (; i < count; i++)
825 if (i != reqpage) {
826 vm_page_lock(m[i]);
827 vm_page_free(m[i]);
828 vm_page_unlock(m[i]);
829 }
830 VM_OBJECT_UNLOCK(object);
831 return (VM_PAGER_ERROR);
832 }
833 if (firstaddr == -1) {
834 VM_OBJECT_LOCK(object);
835 if (i == reqpage && foff < object->un_pager.vnp.vnp_size) {
836 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx",
837 (intmax_t)firstaddr, (uintmax_t)(foff >> 32),
838 (uintmax_t)foff,
839 (uintmax_t)
840 (object->un_pager.vnp.vnp_size >> 32),
841 (uintmax_t)object->un_pager.vnp.vnp_size);
842 }
843 vm_page_lock(m[i]);
844 vm_page_free(m[i]);
845 vm_page_unlock(m[i]);
846 VM_OBJECT_UNLOCK(object);
847 runend = i + 1;
848 first = runend;
849 continue;
850 }
851 runend = i + runpg;
852 if (runend <= reqpage) {
853 VM_OBJECT_LOCK(object);
854 for (j = i; j < runend; j++) {
855 vm_page_lock(m[j]);
856 vm_page_free(m[j]);
857 vm_page_unlock(m[j]);
858 }
859 VM_OBJECT_UNLOCK(object);
860 } else {
861 if (runpg < (count - first)) {
862 VM_OBJECT_LOCK(object);
863 for (i = first + runpg; i < count; i++) {
864 vm_page_lock(m[i]);
865 vm_page_free(m[i]);
866 vm_page_unlock(m[i]);
867 }
868 VM_OBJECT_UNLOCK(object);
869 count = first + runpg;
870 }
871 break;
872 }
873 first = runend;
874 }
875
876 /*
877 * the first and last page have been calculated now, move input pages
878 * to be zero based...
879 */
880 if (first != 0) {
881 m += first;
882 count -= first;
883 reqpage -= first;
884 }
885
886 /*
887 * calculate the file virtual address for the transfer
888 */
889 foff = IDX_TO_OFF(m[0]->pindex);
890
891 /*
892 * calculate the size of the transfer
893 */
894 size = count * PAGE_SIZE;
895 KASSERT(count > 0, ("zero count"));
896 if ((foff + size) > object->un_pager.vnp.vnp_size)
897 size = object->un_pager.vnp.vnp_size - foff;
898 KASSERT(size > 0, ("zero size"));
899
900 /*
901 * round up physical size for real devices.
902 */
903 if (1) {
904 int secmask = bo->bo_bsize - 1;
905 KASSERT(secmask < PAGE_SIZE && secmask > 0,
906 ("vnode_pager_generic_getpages: sector size %d too large",
907 secmask + 1));
908 size = (size + secmask) & ~secmask;
909 }
910
911 bp = getpbuf(&vnode_pbuf_freecnt);
912 kva = (vm_offset_t)bp->b_data;
913
914 /*
915 * and map the pages to be read into the kva, if the filesystem
916 * requires mapped buffers.
917 */
918 mp = vp->v_mount;
919 if (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 &&
920 unmapped_buf_allowed) {
921 bp->b_data = unmapped_buf;
922 bp->b_kvabase = unmapped_buf;
923 bp->b_offset = 0;
924 bp->b_flags |= B_UNMAPPED;
925 bp->b_npages = count;
926 for (i = 0; i < count; i++)
927 bp->b_pages[i] = m[i];
928 } else
929 pmap_qenter(kva, m, count);
930
931 /* build a minimal buffer header */
932 bp->b_iocmd = BIO_READ;
933 bp->b_iodone = bdone;
934 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
935 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
936 bp->b_rcred = crhold(curthread->td_ucred);
937 bp->b_wcred = crhold(curthread->td_ucred);
938 bp->b_blkno = firstaddr;
939 pbgetbo(bo, bp);
940 bp->b_vp = vp;
941 bp->b_bcount = size;
942 bp->b_bufsize = size;
943 bp->b_runningbufspace = bp->b_bufsize;
944 atomic_add_long(&runningbufspace, bp->b_runningbufspace);
945
946 PCPU_INC(cnt.v_vnodein);
947 PCPU_ADD(cnt.v_vnodepgsin, count);
948
949 /* do the input */
950 bp->b_iooffset = dbtob(bp->b_blkno);
951 bstrategy(bp);
952
953 bwait(bp, PVM, "vnread");
954
955 if ((bp->b_ioflags & BIO_ERROR) != 0)
956 error = EIO;
957
958 if (error == 0 && size != count * PAGE_SIZE) {
959 if ((bp->b_flags & B_UNMAPPED) != 0) {
960 bp->b_flags &= ~B_UNMAPPED;
961 pmap_qenter(kva, m, count);
962 }
963 bzero((caddr_t)kva + size, PAGE_SIZE * count - size);
964 }
965 if ((bp->b_flags & B_UNMAPPED) == 0)
966 pmap_qremove(kva, count);
967 if (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0) {
968 bp->b_data = (caddr_t)kva;
969 bp->b_kvabase = (caddr_t)kva;
970 bp->b_flags &= ~B_UNMAPPED;
971 for (i = 0; i < count; i++)
972 bp->b_pages[i] = NULL;
973 }
974
975 /*
976 * free the buffer header back to the swap buffer pool
977 */
978 bp->b_vp = NULL;
979 pbrelbo(bp);
980 relpbuf(bp, &vnode_pbuf_freecnt);
981
982 VM_OBJECT_LOCK(object);
983 for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) {
984 vm_page_t mt;
985
986 nextoff = tfoff + PAGE_SIZE;
987 mt = m[i];
988
989 if (nextoff <= object->un_pager.vnp.vnp_size) {
990 /*
991 * Read filled up entire page.
992 */
993 mt->valid = VM_PAGE_BITS_ALL;
994 KASSERT(mt->dirty == 0,
995 ("vnode_pager_generic_getpages: page %p is dirty",
996 mt));
997 KASSERT(!pmap_page_is_mapped(mt),
998 ("vnode_pager_generic_getpages: page %p is mapped",
999 mt));
1000 } else {
1001 /*
1002 * Read did not fill up entire page.
1003 *
1004 * Currently we do not set the entire page valid,
1005 * we just try to clear the piece that we couldn't
1006 * read.
1007 */
1008 vm_page_set_valid(mt, 0,
1009 object->un_pager.vnp.vnp_size - tfoff);
1010 KASSERT((mt->dirty & vm_page_bits(0,
1011 object->un_pager.vnp.vnp_size - tfoff)) == 0,
1012 ("vnode_pager_generic_getpages: page %p is dirty",
1013 mt));
1014 }
1015
1016 if (i != reqpage)
1017 vm_page_readahead_finish(mt);
1018 }
1019 VM_OBJECT_UNLOCK(object);
1020 if (error) {
1021 printf("vnode_pager_getpages: I/O read error\n");
1022 }
1023 return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
1024 }
1025
1026 /*
1027 * EOPNOTSUPP is no longer legal. For local media VFS's that do not
1028 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
1029 * vnode_pager_generic_putpages() to implement the previous behaviour.
1030 *
1031 * All other FS's should use the bypass to get to the local media
1032 * backing vp's VOP_PUTPAGES.
1033 */
1034 static void
1035 vnode_pager_putpages(object, m, count, sync, rtvals)
1036 vm_object_t object;
1037 vm_page_t *m;
1038 int count;
1039 boolean_t sync;
1040 int *rtvals;
1041 {
1042 int rtval;
1043 struct vnode *vp;
1044 int bytes = count * PAGE_SIZE;
1045
1046 /*
1047 * Force synchronous operation if we are extremely low on memory
1048 * to prevent a low-memory deadlock. VOP operations often need to
1049 * allocate more memory to initiate the I/O ( i.e. do a BMAP
1050 * operation ). The swapper handles the case by limiting the amount
1051 * of asynchronous I/O, but that sort of solution doesn't scale well
1052 * for the vnode pager without a lot of work.
1053 *
1054 * Also, the backing vnode's iodone routine may not wake the pageout
1055 * daemon up. This should be probably be addressed XXX.
1056 */
1057
1058 if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min)
1059 sync |= OBJPC_SYNC;
1060
1061 /*
1062 * Call device-specific putpages function
1063 */
1064 vp = object->handle;
1065 VM_OBJECT_UNLOCK(object);
1066 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0);
1067 KASSERT(rtval != EOPNOTSUPP,
1068 ("vnode_pager: stale FS putpages\n"));
1069 VM_OBJECT_LOCK(object);
1070 }
1071
1072
1073 /*
1074 * This is now called from local media FS's to operate against their
1075 * own vnodes if they fail to implement VOP_PUTPAGES.
1076 *
1077 * This is typically called indirectly via the pageout daemon and
1078 * clustering has already typically occured, so in general we ask the
1079 * underlying filesystem to write the data out asynchronously rather
1080 * then delayed.
1081 */
1082 int
1083 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount,
1084 int flags, int *rtvals)
1085 {
1086 int i;
1087 vm_object_t object;
1088 vm_page_t m;
1089 int count;
1090
1091 int maxsize, ncount;
1092 vm_ooffset_t poffset;
1093 struct uio auio;
1094 struct iovec aiov;
1095 int error;
1096 int ioflags;
1097 int ppscheck = 0;
1098 static struct timeval lastfail;
1099 static int curfail;
1100
1101 object = vp->v_object;
1102 count = bytecount / PAGE_SIZE;
1103
1104 for (i = 0; i < count; i++)
1105 rtvals[i] = VM_PAGER_ERROR;
1106
1107 if ((int64_t)ma[0]->pindex < 0) {
1108 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n",
1109 (long)ma[0]->pindex, (u_long)ma[0]->dirty);
1110 rtvals[0] = VM_PAGER_BAD;
1111 return VM_PAGER_BAD;
1112 }
1113
1114 maxsize = count * PAGE_SIZE;
1115 ncount = count;
1116
1117 poffset = IDX_TO_OFF(ma[0]->pindex);
1118
1119 /*
1120 * If the page-aligned write is larger then the actual file we
1121 * have to invalidate pages occuring beyond the file EOF. However,
1122 * there is an edge case where a file may not be page-aligned where
1123 * the last page is partially invalid. In this case the filesystem
1124 * may not properly clear the dirty bits for the entire page (which
1125 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d).
1126 * With the page locked we are free to fix-up the dirty bits here.
1127 *
1128 * We do not under any circumstances truncate the valid bits, as
1129 * this will screw up bogus page replacement.
1130 */
1131 VM_OBJECT_LOCK(object);
1132 if (maxsize + poffset > object->un_pager.vnp.vnp_size) {
1133 if (object->un_pager.vnp.vnp_size > poffset) {
1134 int pgoff;
1135
1136 maxsize = object->un_pager.vnp.vnp_size - poffset;
1137 ncount = btoc(maxsize);
1138 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) {
1139 /*
1140 * If the object is locked and the following
1141 * conditions hold, then the page's dirty
1142 * field cannot be concurrently changed by a
1143 * pmap operation.
1144 */
1145 m = ma[ncount - 1];
1146 KASSERT(m->busy > 0,
1147 ("vnode_pager_generic_putpages: page %p is not busy", m));
1148 KASSERT(!pmap_page_is_write_mapped(m),
1149 ("vnode_pager_generic_putpages: page %p is not read-only", m));
1150 vm_page_clear_dirty(m, pgoff, PAGE_SIZE -
1151 pgoff);
1152 }
1153 } else {
1154 maxsize = 0;
1155 ncount = 0;
1156 }
1157 if (ncount < count) {
1158 for (i = ncount; i < count; i++) {
1159 rtvals[i] = VM_PAGER_BAD;
1160 }
1161 }
1162 }
1163 VM_OBJECT_UNLOCK(object);
1164
1165 /*
1166 * pageouts are already clustered, use IO_ASYNC t o force a bawrite()
1167 * rather then a bdwrite() to prevent paging I/O from saturating
1168 * the buffer cache. Dummy-up the sequential heuristic to cause
1169 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set,
1170 * the system decides how to cluster.
1171 */
1172 ioflags = IO_VMIO;
1173 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL))
1174 ioflags |= IO_SYNC;
1175 else if ((flags & VM_PAGER_CLUSTER_OK) == 0)
1176 ioflags |= IO_ASYNC;
1177 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0;
1178 ioflags |= IO_SEQMAX << IO_SEQSHIFT;
1179
1180 aiov.iov_base = (caddr_t) 0;
1181 aiov.iov_len = maxsize;
1182 auio.uio_iov = &aiov;
1183 auio.uio_iovcnt = 1;
1184 auio.uio_offset = poffset;
1185 auio.uio_segflg = UIO_NOCOPY;
1186 auio.uio_rw = UIO_WRITE;
1187 auio.uio_resid = maxsize;
1188 auio.uio_td = (struct thread *) 0;
1189 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred);
1190 PCPU_INC(cnt.v_vnodeout);
1191 PCPU_ADD(cnt.v_vnodepgsout, ncount);
1192
1193 if (error) {
1194 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1)))
1195 printf("vnode_pager_putpages: I/O error %d\n", error);
1196 }
1197 if (auio.uio_resid) {
1198 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1))
1199 printf("vnode_pager_putpages: residual I/O %zd at %lu\n",
1200 auio.uio_resid, (u_long)ma[0]->pindex);
1201 }
1202 for (i = 0; i < ncount; i++) {
1203 rtvals[i] = VM_PAGER_OK;
1204 }
1205 return rtvals[0];
1206 }
1207
1208 void
1209 vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written)
1210 {
1211 vm_object_t obj;
1212 int i, pos;
1213
1214 if (written == 0)
1215 return;
1216 obj = ma[0]->object;
1217 VM_OBJECT_LOCK(obj);
1218 for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) {
1219 if (pos < trunc_page(written)) {
1220 rtvals[i] = VM_PAGER_OK;
1221 vm_page_undirty(ma[i]);
1222 } else {
1223 /* Partially written page. */
1224 rtvals[i] = VM_PAGER_AGAIN;
1225 vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK);
1226 }
1227 }
1228 VM_OBJECT_UNLOCK(obj);
1229 }
1230
1231 void
1232 vnode_pager_update_writecount(vm_object_t object, vm_offset_t start,
1233 vm_offset_t end)
1234 {
1235 struct vnode *vp;
1236 vm_ooffset_t old_wm;
1237
1238 VM_OBJECT_LOCK(object);
1239 if (object->type != OBJT_VNODE) {
1240 VM_OBJECT_UNLOCK(object);
1241 return;
1242 }
1243 old_wm = object->un_pager.vnp.writemappings;
1244 object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start;
1245 vp = object->handle;
1246 if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) {
1247 ASSERT_VOP_ELOCKED(vp, "v_writecount inc");
1248 VOP_ADD_WRITECOUNT(vp, 1);
1249 } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) {
1250 ASSERT_VOP_ELOCKED(vp, "v_writecount dec");
1251 VOP_ADD_WRITECOUNT(vp, -1);
1252 }
1253 VM_OBJECT_UNLOCK(object);
1254 }
1255
1256 void
1257 vnode_pager_release_writecount(vm_object_t object, vm_offset_t start,
1258 vm_offset_t end)
1259 {
1260 struct vnode *vp;
1261 struct mount *mp;
1262 vm_offset_t inc;
1263 int vfslocked;
1264
1265 VM_OBJECT_LOCK(object);
1266
1267 /*
1268 * First, recheck the object type to account for the race when
1269 * the vnode is reclaimed.
1270 */
1271 if (object->type != OBJT_VNODE) {
1272 VM_OBJECT_UNLOCK(object);
1273 return;
1274 }
1275
1276 /*
1277 * Optimize for the case when writemappings is not going to
1278 * zero.
1279 */
1280 inc = end - start;
1281 if (object->un_pager.vnp.writemappings != inc) {
1282 object->un_pager.vnp.writemappings -= inc;
1283 VM_OBJECT_UNLOCK(object);
1284 return;
1285 }
1286
1287 vp = object->handle;
1288 vhold(vp);
1289 VM_OBJECT_UNLOCK(object);
1290 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
1291 mp = NULL;
1292 vn_start_write(vp, &mp, V_WAIT);
1293 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1294
1295 /*
1296 * Decrement the object's writemappings, by swapping the start
1297 * and end arguments for vnode_pager_update_writecount(). If
1298 * there was not a race with vnode reclaimation, then the
1299 * vnode's v_writecount is decremented.
1300 */
1301 vnode_pager_update_writecount(object, end, start);
1302 VOP_UNLOCK(vp, 0);
1303 vdrop(vp);
1304 if (mp != NULL)
1305 vn_finished_write(mp);
1306 VFS_UNLOCK_GIANT(vfslocked);
1307 }
Cache object: b3f55d9db610cf084536611df92a7e00
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