kernel - disklabel64 - Increase partition start alignment to 1 megabyte.
[dragonfly.git] / sys / vm / vnode_pager.c
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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
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.
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.
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.
40 * from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91
41 * $FreeBSD: src/sys/vm/vnode_pager.c,v 1.116.2.7 2002/12/31 09:34:51 dillon Exp $
42 * $DragonFly: src/sys/vm/vnode_pager.c,v 1.43 2008/06/19 23:27:39 dillon Exp $
46 * Page to/from files (vnodes).
50 * TODO:
51 * Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will
52 * greatly re-simplify the vnode_pager.
55 #include <sys/param.h>
56 #include <sys/systm.h>
57 #include <sys/kernel.h>
58 #include <sys/proc.h>
59 #include <sys/vnode.h>
60 #include <sys/mount.h>
61 #include <sys/buf.h>
62 #include <sys/vmmeter.h>
63 #include <sys/conf.h>
64 #include <sys/sfbuf.h>
66 #include <vm/vm.h>
67 #include <vm/vm_object.h>
68 #include <vm/vm_page.h>
69 #include <vm/vm_pager.h>
70 #include <vm/vm_map.h>
71 #include <vm/vnode_pager.h>
72 #include <vm/swap_pager.h>
73 #include <vm/vm_extern.h>
75 #include <sys/thread2.h>
76 #include <vm/vm_page2.h>
78 static void vnode_pager_dealloc (vm_object_t);
79 static int vnode_pager_getpage (vm_object_t, vm_page_t *, int);
80 static void vnode_pager_putpages (vm_object_t, vm_page_t *, int, boolean_t, int *);
81 static boolean_t vnode_pager_haspage (vm_object_t, vm_pindex_t);
83 struct pagerops vnodepagerops = {
84 vnode_pager_dealloc,
85 vnode_pager_getpage,
86 vnode_pager_putpages,
87 vnode_pager_haspage
90 static struct krate vbadrate = { 1 };
91 static struct krate vresrate = { 1 };
93 int vnode_pbuf_freecnt = -1; /* start out unlimited */
96 * Allocate a VM object for a vnode, typically a regular file vnode.
98 * Some additional information is required to generate a properly sized
99 * object which covers the entire buffer cache buffer straddling the file
100 * EOF. Userland does not see the extra pages as the VM fault code tests
101 * against v_filesize.
103 vm_object_t
104 vnode_pager_alloc(void *handle, off_t length, vm_prot_t prot, off_t offset,
105 int blksize, int boff)
107 vm_object_t object;
108 struct vnode *vp;
109 off_t loffset;
110 vm_pindex_t lsize;
113 * Pageout to vnode, no can do yet.
115 if (handle == NULL)
116 return (NULL);
119 * XXX hack - This initialization should be put somewhere else.
121 if (vnode_pbuf_freecnt < 0) {
122 vnode_pbuf_freecnt = nswbuf / 2 + 1;
125 vp = (struct vnode *) handle;
128 * Prevent race condition when allocating the object. This
129 * can happen with NFS vnodes since the nfsnode isn't locked.
131 while (vp->v_flag & VOLOCK) {
132 vsetflags(vp, VOWANT);
133 tsleep(vp, 0, "vnpobj", 0);
135 vsetflags(vp, VOLOCK);
138 * If the object is being terminated, wait for it to
139 * go away.
141 while (((object = vp->v_object) != NULL) &&
142 (object->flags & OBJ_DEAD)) {
143 vm_object_dead_sleep(object, "vadead");
146 if (vp->v_sysref.refcnt <= 0)
147 panic("vnode_pager_alloc: no vnode reference");
150 * Round up to the *next* block, then destroy the buffers in question.
151 * Since we are only removing some of the buffers we must rely on the
152 * scan count to determine whether a loop is necessary.
154 * Destroy any pages beyond the last buffer.
156 if (boff < 0)
157 boff = (int)(length % blksize);
158 if (boff)
159 loffset = length + (blksize - boff);
160 else
161 loffset = length;
162 lsize = OFF_TO_IDX(round_page64(loffset));
164 if (object == NULL) {
166 * And an object of the appropriate size
168 object = vm_object_allocate(OBJT_VNODE, lsize);
169 object->flags = 0;
170 object->handle = handle;
171 vp->v_object = object;
172 vp->v_filesize = length;
173 if (vp->v_mount && (vp->v_mount->mnt_kern_flag & MNTK_NOMSYNC))
174 object->flags |= OBJ_NOMSYNC;
175 } else {
176 object->ref_count++;
177 if (object->size != lsize) {
178 kprintf("vnode_pager_alloc: Warning, objsize "
179 "mismatch %jd/%jd vp=%p obj=%p\n",
180 (intmax_t)object->size,
181 (intmax_t)lsize,
182 vp, object);
184 if (vp->v_filesize != length) {
185 kprintf("vnode_pager_alloc: Warning, filesize "
186 "mismatch %jd/%jd vp=%p obj=%p\n",
187 (intmax_t)vp->v_filesize,
188 (intmax_t)length,
189 vp, object);
192 vref(vp);
194 vclrflags(vp, VOLOCK);
195 if (vp->v_flag & VOWANT) {
196 vclrflags(vp, VOWANT);
197 wakeup(vp);
199 return (object);
203 * Add a ref to a vnode's existing VM object, return the object or
204 * NULL if the vnode did not have one. This does not create the
205 * object (we can't since we don't know what the proper blocksize/boff
206 * is to match the VFS's use of the buffer cache).
208 vm_object_t
209 vnode_pager_reference(struct vnode *vp)
211 vm_object_t object;
214 * Prevent race condition when allocating the object. This
215 * can happen with NFS vnodes since the nfsnode isn't locked.
217 while (vp->v_flag & VOLOCK) {
218 vsetflags(vp, VOWANT);
219 tsleep(vp, 0, "vnpobj", 0);
221 vsetflags(vp, VOLOCK);
224 * Prevent race conditions against deallocation of the VM
225 * object.
227 while (((object = vp->v_object) != NULL) &&
228 (object->flags & OBJ_DEAD)) {
229 vm_object_dead_sleep(object, "vadead");
233 * The object is expected to exist, the caller will handle
234 * NULL returns if it does not.
236 if (object) {
237 object->ref_count++;
238 vref(vp);
241 vclrflags(vp, VOLOCK);
242 if (vp->v_flag & VOWANT) {
243 vclrflags(vp, VOWANT);
244 wakeup(vp);
246 return (object);
249 static void
250 vnode_pager_dealloc(vm_object_t object)
252 struct vnode *vp = object->handle;
254 if (vp == NULL)
255 panic("vnode_pager_dealloc: pager already dealloced");
257 vm_object_pip_wait(object, "vnpdea");
259 object->handle = NULL;
260 object->type = OBJT_DEAD;
261 vp->v_object = NULL;
262 vp->v_filesize = NOOFFSET;
263 vclrflags(vp, VTEXT | VOBJBUF);
264 swap_pager_freespace_all(object);
268 * Return whether the vnode pager has the requested page. Return the
269 * number of disk-contiguous pages before and after the requested page,
270 * not including the requested page.
272 static boolean_t
273 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex)
275 struct vnode *vp = object->handle;
276 off_t loffset;
277 off_t doffset;
278 int voff;
279 int bsize;
280 int error;
283 * If no vp or vp is doomed or marked transparent to VM, we do not
284 * have the page.
286 if ((vp == NULL) || (vp->v_flag & VRECLAIMED))
287 return FALSE;
290 * If filesystem no longer mounted or offset beyond end of file we do
291 * not have the page.
293 loffset = IDX_TO_OFF(pindex);
295 if (vp->v_mount == NULL || loffset >= vp->v_filesize)
296 return FALSE;
298 bsize = vp->v_mount->mnt_stat.f_iosize;
299 voff = loffset % bsize;
302 * XXX
304 * BMAP returns byte counts before and after, where after
305 * is inclusive of the base page. haspage must return page
306 * counts before and after where after does not include the
307 * base page.
309 * BMAP is allowed to return a *after of 0 for backwards
310 * compatibility. The base page is still considered valid if
311 * no error is returned.
313 error = VOP_BMAP(vp, loffset - voff, &doffset, NULL, NULL, 0);
314 if (error)
315 return TRUE;
316 if (doffset == NOOFFSET)
317 return FALSE;
318 return TRUE;
322 * Lets the VM system know about a change in size for a file.
323 * We adjust our own internal size and flush any cached pages in
324 * the associated object that are affected by the size change.
326 * NOTE: This routine may be invoked as a result of a pager put
327 * operation (possibly at object termination time), so we must be careful.
329 * NOTE: vp->v_filesize is initialized to NOOFFSET (-1), be sure that
330 * we do not blow up on the case. nsize will always be >= 0, however.
332 void
333 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize)
335 vm_pindex_t nobjsize;
336 vm_pindex_t oobjsize;
337 vm_object_t object = vp->v_object;
339 if (object == NULL)
340 return;
343 * Hasn't changed size
345 if (nsize == vp->v_filesize)
346 return;
349 * Has changed size. Adjust the VM object's size and v_filesize
350 * before we start scanning pages to prevent new pages from being
351 * allocated during the scan.
353 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
354 oobjsize = object->size;
355 object->size = nobjsize;
358 * File has shrunk. Toss any cached pages beyond the new EOF.
360 if (nsize < vp->v_filesize) {
361 vp->v_filesize = nsize;
362 if (nobjsize < oobjsize) {
363 vm_object_page_remove(object, nobjsize, oobjsize,
364 FALSE);
367 * This gets rid of garbage at the end of a page that is now
368 * only partially backed by the vnode. Since we are setting
369 * the entire page valid & clean after we are done we have
370 * to be sure that the portion of the page within the file
371 * bounds is already valid. If it isn't then making it
372 * valid would create a corrupt block.
374 if (nsize & PAGE_MASK) {
375 vm_offset_t kva;
376 vm_page_t m;
378 do {
379 m = vm_page_lookup(object, OFF_TO_IDX(nsize));
380 } while (m && vm_page_sleep_busy(m, TRUE, "vsetsz"));
382 if (m && m->valid) {
383 int base = (int)nsize & PAGE_MASK;
384 int size = PAGE_SIZE - base;
385 struct sf_buf *sf;
388 * Clear out partial-page garbage in case
389 * the page has been mapped.
391 * This is byte aligned.
393 vm_page_busy(m);
394 sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
395 kva = sf_buf_kva(sf);
396 bzero((caddr_t)kva + base, size);
397 sf_buf_free(sf);
400 * XXX work around SMP data integrity race
401 * by unmapping the page from user processes.
402 * The garbage we just cleared may be mapped
403 * to a user process running on another cpu
404 * and this code is not running through normal
405 * I/O channels which handle SMP issues for
406 * us, so unmap page to synchronize all cpus.
408 * XXX should vm_pager_unmap_page() have
409 * dealt with this?
411 vm_page_protect(m, VM_PROT_NONE);
414 * Clear out partial-page dirty bits. This
415 * has the side effect of setting the valid
416 * bits, but that is ok. There are a bunch
417 * of places in the VM system where we expected
418 * m->dirty == VM_PAGE_BITS_ALL. The file EOF
419 * case is one of them. If the page is still
420 * partially dirty, make it fully dirty.
422 * NOTE: We do not clear out the valid
423 * bits. This would prevent bogus_page
424 * replacement from working properly.
426 * NOTE: We do not want to clear the dirty
427 * bit for a partial DEV_BSIZE'd truncation!
428 * This is DEV_BSIZE aligned!
430 vm_page_clear_dirty_beg_nonincl(m, base, size);
431 if (m->dirty != 0)
432 m->dirty = VM_PAGE_BITS_ALL;
433 vm_page_wakeup(m);
436 } else {
437 vp->v_filesize = nsize;
442 * Release a page busied for a getpages operation. The page may have become
443 * wired (typically due to being used by the buffer cache) or otherwise been
444 * soft-busied and cannot be freed in that case. A held page can still be
445 * freed.
447 void
448 vnode_pager_freepage(vm_page_t m)
450 if (m->busy || m->wire_count) {
451 vm_page_activate(m);
452 vm_page_wakeup(m);
453 } else {
454 vm_page_free(m);
459 * EOPNOTSUPP is no longer legal. For local media VFS's that do not
460 * implement their own VOP_GETPAGES, their VOP_GETPAGES should call to
461 * vnode_pager_generic_getpages() to implement the previous behaviour.
463 * All other FS's should use the bypass to get to the local media
464 * backing vp's VOP_GETPAGES.
466 static int
467 vnode_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess)
469 int rtval;
470 struct vnode *vp;
472 vp = object->handle;
473 rtval = VOP_GETPAGES(vp, mpp, PAGE_SIZE, 0, 0, seqaccess);
474 if (rtval == EOPNOTSUPP)
475 panic("vnode_pager: vfs's must implement vop_getpages\n");
476 return rtval;
480 * This is now called from local media FS's to operate against their
481 * own vnodes if they fail to implement VOP_GETPAGES.
483 * With all the caching local media devices do these days there is really
484 * very little point to attempting to restrict the I/O size to contiguous
485 * blocks on-disk, especially if our caller thinks we need all the specified
486 * pages. Just construct and issue a READ.
489 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *mpp, int bytecount,
490 int reqpage, int seqaccess)
492 struct iovec aiov;
493 struct uio auio;
494 off_t foff;
495 int error;
496 int count;
497 int i;
498 int ioflags;
501 * Do not do anything if the vnode is bad.
503 if (vp->v_mount == NULL)
504 return VM_PAGER_BAD;
507 * Calculate the number of pages. Since we are paging in whole
508 * pages, adjust bytecount to be an integral multiple of the page
509 * size. It will be clipped to the file EOF later on.
511 bytecount = round_page(bytecount);
512 count = bytecount / PAGE_SIZE;
515 * We could check m[reqpage]->valid here and shortcut the operation,
516 * but doing so breaks read-ahead. Instead assume that the VM
517 * system has already done at least the check, don't worry about
518 * any races, and issue the VOP_READ to allow read-ahead to function.
520 * This keeps the pipeline full for I/O bound sequentially scanned
521 * mmap()'s
523 /* don't shortcut */
526 * Discard pages past the file EOF. If the requested page is past
527 * the file EOF we just leave its valid bits set to 0, the caller
528 * expects to maintain ownership of the requested page. If the
529 * entire range is past file EOF discard everything and generate
530 * a pagein error.
532 foff = IDX_TO_OFF(mpp[0]->pindex);
533 if (foff >= vp->v_filesize) {
534 for (i = 0; i < count; i++) {
535 if (i != reqpage)
536 vnode_pager_freepage(mpp[i]);
538 return VM_PAGER_ERROR;
541 if (foff + bytecount > vp->v_filesize) {
542 bytecount = vp->v_filesize - foff;
543 i = round_page(bytecount) / PAGE_SIZE;
544 while (count > i) {
545 --count;
546 if (count != reqpage)
547 vnode_pager_freepage(mpp[count]);
552 * The size of the transfer is bytecount. bytecount will be an
553 * integral multiple of the page size unless it has been clipped
554 * to the file EOF. The transfer cannot exceed the file EOF.
556 * When dealing with real devices we must round-up to the device
557 * sector size.
559 if (vp->v_type == VBLK || vp->v_type == VCHR) {
560 int secmask = vp->v_rdev->si_bsize_phys - 1;
561 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1));
562 bytecount = (bytecount + secmask) & ~secmask;
566 * Severe hack to avoid deadlocks with the buffer cache
568 for (i = 0; i < count; ++i) {
569 vm_page_t mt = mpp[i];
571 vm_page_io_start(mt);
572 vm_page_wakeup(mt);
576 * Issue the I/O with some read-ahead if bytecount > PAGE_SIZE
578 ioflags = IO_VMIO;
579 if (seqaccess)
580 ioflags |= IO_SEQMAX << IO_SEQSHIFT;
582 aiov.iov_base = NULL;
583 aiov.iov_len = bytecount;
584 auio.uio_iov = &aiov;
585 auio.uio_iovcnt = 1;
586 auio.uio_offset = foff;
587 auio.uio_segflg = UIO_NOCOPY;
588 auio.uio_rw = UIO_READ;
589 auio.uio_resid = bytecount;
590 auio.uio_td = NULL;
591 mycpu->gd_cnt.v_vnodein++;
592 mycpu->gd_cnt.v_vnodepgsin += count;
594 error = VOP_READ(vp, &auio, ioflags, proc0.p_ucred);
597 * Severe hack to avoid deadlocks with the buffer cache
599 for (i = 0; i < count; ++i) {
600 vm_page_t mt = mpp[i];
602 while (vm_page_sleep_busy(mt, FALSE, "getpgs"))
604 vm_page_busy(mt);
605 vm_page_io_finish(mt);
609 * Calculate the actual number of bytes read and clean up the
610 * page list.
612 bytecount -= auio.uio_resid;
614 for (i = 0; i < count; ++i) {
615 vm_page_t mt = mpp[i];
617 if (i != reqpage) {
618 if (error == 0 && mt->valid) {
619 if (mt->flags & PG_WANTED)
620 vm_page_activate(mt);
621 else
622 vm_page_deactivate(mt);
623 vm_page_wakeup(mt);
624 } else {
625 vnode_pager_freepage(mt);
627 } else if (mt->valid == 0) {
628 if (error == 0) {
629 kprintf("page failed but no I/O error page %p object %p pindex %d\n", mt, mt->object, (int) mt->pindex);
630 /* whoops, something happened */
631 error = EINVAL;
633 } else if (mt->valid != VM_PAGE_BITS_ALL) {
635 * Zero-extend the requested page if necessary (if
636 * the filesystem is using a small block size).
638 vm_page_zero_invalid(mt, TRUE);
641 if (error) {
642 kprintf("vnode_pager_getpage: I/O read error\n");
644 return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
648 * EOPNOTSUPP is no longer legal. For local media VFS's that do not
649 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
650 * vnode_pager_generic_putpages() to implement the previous behaviour.
652 * Caller has already cleared the pmap modified bits, if any.
654 * All other FS's should use the bypass to get to the local media
655 * backing vp's VOP_PUTPAGES.
657 static void
658 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count,
659 boolean_t sync, int *rtvals)
661 int rtval;
662 struct vnode *vp;
663 int bytes = count * PAGE_SIZE;
666 * Force synchronous operation if we are extremely low on memory
667 * to prevent a low-memory deadlock. VOP operations often need to
668 * allocate more memory to initiate the I/O ( i.e. do a BMAP
669 * operation ). The swapper handles the case by limiting the amount
670 * of asynchronous I/O, but that sort of solution doesn't scale well
671 * for the vnode pager without a lot of work.
673 * Also, the backing vnode's iodone routine may not wake the pageout
674 * daemon up. This should be probably be addressed XXX.
677 if ((vmstats.v_free_count + vmstats.v_cache_count) < vmstats.v_pageout_free_min)
678 sync |= OBJPC_SYNC;
681 * Call device-specific putpages function
683 vp = object->handle;
684 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0);
685 if (rtval == EOPNOTSUPP) {
686 kprintf("vnode_pager: *** WARNING *** stale FS putpages\n");
687 rtval = vnode_pager_generic_putpages( vp, m, bytes, sync, rtvals);
693 * This is now called from local media FS's to operate against their
694 * own vnodes if they fail to implement VOP_PUTPAGES.
696 * This is typically called indirectly via the pageout daemon and
697 * clustering has already typically occured, so in general we ask the
698 * underlying filesystem to write the data out asynchronously rather
699 * then delayed.
702 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *m, int bytecount,
703 int flags, int *rtvals)
705 int i;
706 vm_object_t object;
707 int maxsize, ncount, count;
708 vm_ooffset_t poffset;
709 struct uio auio;
710 struct iovec aiov;
711 int error;
712 int ioflags;
714 object = vp->v_object;
715 count = bytecount / PAGE_SIZE;
717 for (i = 0; i < count; i++)
718 rtvals[i] = VM_PAGER_AGAIN;
720 if ((int) m[0]->pindex < 0) {
721 kprintf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n",
722 (long)m[0]->pindex, m[0]->dirty);
723 rtvals[0] = VM_PAGER_BAD;
724 return VM_PAGER_BAD;
727 maxsize = count * PAGE_SIZE;
728 ncount = count;
730 poffset = IDX_TO_OFF(m[0]->pindex);
733 * If the page-aligned write is larger then the actual file we
734 * have to invalidate pages occuring beyond the file EOF.
736 * If the file EOF resides in the middle of a page we still clear
737 * all of that page's dirty bits later on. If we didn't it would
738 * endlessly re-write.
740 * We do not under any circumstances truncate the valid bits, as
741 * this will screw up bogus page replacement.
743 * The caller has already read-protected the pages. The VFS must
744 * use the buffer cache to wrap the pages. The pages might not
745 * be immediately flushed by the buffer cache but once under its
746 * control the pages themselves can wind up being marked clean
747 * and their covering buffer cache buffer can be marked dirty.
749 if (poffset + maxsize > vp->v_filesize) {
750 if (poffset < vp->v_filesize) {
751 maxsize = vp->v_filesize - poffset;
752 ncount = btoc(maxsize);
753 } else {
754 maxsize = 0;
755 ncount = 0;
757 if (ncount < count) {
758 for (i = ncount; i < count; i++) {
759 rtvals[i] = VM_PAGER_BAD;
765 * pageouts are already clustered, use IO_ASYNC to force a bawrite()
766 * rather then a bdwrite() to prevent paging I/O from saturating
767 * the buffer cache. Dummy-up the sequential heuristic to cause
768 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set,
769 * the system decides how to cluster.
771 ioflags = IO_VMIO;
772 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL))
773 ioflags |= IO_SYNC;
774 else if ((flags & VM_PAGER_CLUSTER_OK) == 0)
775 ioflags |= IO_ASYNC;
776 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0;
777 ioflags |= IO_SEQMAX << IO_SEQSHIFT;
779 aiov.iov_base = (caddr_t) 0;
780 aiov.iov_len = maxsize;
781 auio.uio_iov = &aiov;
782 auio.uio_iovcnt = 1;
783 auio.uio_offset = poffset;
784 auio.uio_segflg = UIO_NOCOPY;
785 auio.uio_rw = UIO_WRITE;
786 auio.uio_resid = maxsize;
787 auio.uio_td = NULL;
788 error = VOP_WRITE(vp, &auio, ioflags, proc0.p_ucred);
789 mycpu->gd_cnt.v_vnodeout++;
790 mycpu->gd_cnt.v_vnodepgsout += ncount;
792 if (error) {
793 krateprintf(&vbadrate,
794 "vnode_pager_putpages: I/O error %d\n", error);
796 if (auio.uio_resid) {
797 krateprintf(&vresrate,
798 "vnode_pager_putpages: residual I/O %zd at %lu\n",
799 auio.uio_resid, (u_long)m[0]->pindex);
801 if (error == 0) {
802 for (i = 0; i < ncount; i++) {
803 rtvals[i] = VM_PAGER_OK;
804 vm_page_undirty(m[i]);
807 return rtvals[0];
810 struct vnode *
811 vnode_pager_lock(vm_object_t object)
813 struct thread *td = curthread; /* XXX */
814 int error;
816 for (; object != NULL; object = object->backing_object) {
817 if (object->type != OBJT_VNODE)
818 continue;
819 if (object->flags & OBJ_DEAD)
820 return NULL;
822 for (;;) {
823 struct vnode *vp = object->handle;
824 error = vget(vp, LK_SHARED | LK_RETRY | LK_CANRECURSE);
825 if (error == 0) {
826 if (object->handle != vp) {
827 vput(vp);
828 continue;
830 return (vp);
832 if ((object->flags & OBJ_DEAD) ||
833 (object->type != OBJT_VNODE)) {
834 return NULL;
836 kprintf("vnode_pager_lock: vp %p error %d lockstatus %d, retrying\n", vp, error, lockstatus(&vp->v_lock, td));
837 tsleep(object->handle, 0, "vnpgrl", hz);
840 return NULL;