kernel - SWAP CACHE part 15/many - Correct bug in vm.swapcache.maxfilesize
[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_alloc,
85 vnode_pager_dealloc,
86 vnode_pager_getpage,
87 vnode_pager_putpages,
88 vnode_pager_haspage
91 static struct krate vbadrate = { 1 };
92 static struct krate vresrate = { 1 };
94 int vnode_pbuf_freecnt = -1; /* start out unlimited */
97 * Allocate (or lookup) pager for a vnode.
98 * Handle is a vnode pointer.
100 vm_object_t
101 vnode_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t offset)
103 vm_object_t object;
104 struct vnode *vp;
107 * Pageout to vnode, no can do yet.
109 if (handle == NULL)
110 return (NULL);
113 * XXX hack - This initialization should be put somewhere else.
115 if (vnode_pbuf_freecnt < 0) {
116 vnode_pbuf_freecnt = nswbuf / 2 + 1;
119 vp = (struct vnode *) handle;
122 * Prevent race condition when allocating the object. This
123 * can happen with NFS vnodes since the nfsnode isn't locked.
125 while (vp->v_flag & VOLOCK) {
126 vsetflags(vp, VOWANT);
127 tsleep(vp, 0, "vnpobj", 0);
129 vsetflags(vp, VOLOCK);
132 * If the object is being terminated, wait for it to
133 * go away.
135 while (((object = vp->v_object) != NULL) &&
136 (object->flags & OBJ_DEAD)) {
137 vm_object_dead_sleep(object, "vadead");
140 if (vp->v_sysref.refcnt <= 0)
141 panic("vnode_pager_alloc: no vnode reference");
143 if (object == NULL) {
145 * And an object of the appropriate size
147 object = vm_object_allocate(OBJT_VNODE,
148 OFF_TO_IDX(round_page64(size)));
149 object->flags = 0;
150 object->handle = handle;
151 vp->v_object = object;
152 vp->v_filesize = size;
153 } else {
154 object->ref_count++;
155 if (vp->v_filesize != size) {
156 kprintf("vnode_pager_alloc: Warning, filesize "
157 "mismatch %lld/%lld\n",
158 (long long)vp->v_filesize,
159 (long long)size);
162 vref(vp);
164 vclrflags(vp, VOLOCK);
165 if (vp->v_flag & VOWANT) {
166 vclrflags(vp, VOWANT);
167 wakeup(vp);
169 return (object);
172 static void
173 vnode_pager_dealloc(vm_object_t object)
175 struct vnode *vp = object->handle;
177 if (vp == NULL)
178 panic("vnode_pager_dealloc: pager already dealloced");
180 vm_object_pip_wait(object, "vnpdea");
182 object->handle = NULL;
183 object->type = OBJT_DEAD;
184 vp->v_object = NULL;
185 vp->v_filesize = NOOFFSET;
186 vclrflags(vp, VTEXT | VOBJBUF);
187 swap_pager_freespace_all(object);
191 * Return whether the vnode pager has the requested page. Return the
192 * number of disk-contiguous pages before and after the requested page,
193 * not including the requested page.
195 static boolean_t
196 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex)
198 struct vnode *vp = object->handle;
199 off_t loffset;
200 off_t doffset;
201 int voff;
202 int bsize;
203 int error;
206 * If no vp or vp is doomed or marked transparent to VM, we do not
207 * have the page.
209 if ((vp == NULL) || (vp->v_flag & VRECLAIMED))
210 return FALSE;
213 * If filesystem no longer mounted or offset beyond end of file we do
214 * not have the page.
216 loffset = IDX_TO_OFF(pindex);
218 if (vp->v_mount == NULL || loffset >= vp->v_filesize)
219 return FALSE;
221 bsize = vp->v_mount->mnt_stat.f_iosize;
222 voff = loffset % bsize;
225 * XXX
227 * BMAP returns byte counts before and after, where after
228 * is inclusive of the base page. haspage must return page
229 * counts before and after where after does not include the
230 * base page.
232 * BMAP is allowed to return a *after of 0 for backwards
233 * compatibility. The base page is still considered valid if
234 * no error is returned.
236 error = VOP_BMAP(vp, loffset - voff, &doffset, NULL, NULL, 0);
237 if (error)
238 return TRUE;
239 if (doffset == NOOFFSET)
240 return FALSE;
241 return TRUE;
245 * Lets the VM system know about a change in size for a file.
246 * We adjust our own internal size and flush any cached pages in
247 * the associated object that are affected by the size change.
249 * NOTE: This routine may be invoked as a result of a pager put
250 * operation (possibly at object termination time), so we must be careful.
252 * NOTE: vp->v_filesize is initialized to NOOFFSET (-1), be sure that
253 * we do not blow up on the case. nsize will always be >= 0, however.
255 void
256 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize)
258 vm_pindex_t nobjsize;
259 vm_pindex_t oobjsize;
260 vm_object_t object = vp->v_object;
262 if (object == NULL)
263 return;
266 * Hasn't changed size
268 if (nsize == vp->v_filesize)
269 return;
272 * Has changed size. Adjust the VM object's size and v_filesize
273 * before we start scanning pages to prevent new pages from being
274 * allocated during the scan.
276 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
277 oobjsize = object->size;
278 object->size = nobjsize;
281 * File has shrunk. Toss any cached pages beyond the new EOF.
283 if (nsize < vp->v_filesize) {
284 vp->v_filesize = nsize;
285 if (nobjsize < oobjsize) {
286 vm_object_page_remove(object, nobjsize, oobjsize,
287 FALSE);
290 * This gets rid of garbage at the end of a page that is now
291 * only partially backed by the vnode. Since we are setting
292 * the entire page valid & clean after we are done we have
293 * to be sure that the portion of the page within the file
294 * bounds is already valid. If it isn't then making it
295 * valid would create a corrupt block.
297 if (nsize & PAGE_MASK) {
298 vm_offset_t kva;
299 vm_page_t m;
301 do {
302 m = vm_page_lookup(object, OFF_TO_IDX(nsize));
303 } while (m && vm_page_sleep_busy(m, TRUE, "vsetsz"));
305 if (m && m->valid) {
306 int base = (int)nsize & PAGE_MASK;
307 int size = PAGE_SIZE - base;
308 struct sf_buf *sf;
311 * Clear out partial-page garbage in case
312 * the page has been mapped.
314 * This is byte aligned.
316 vm_page_busy(m);
317 sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
318 kva = sf_buf_kva(sf);
319 bzero((caddr_t)kva + base, size);
320 sf_buf_free(sf);
323 * XXX work around SMP data integrity race
324 * by unmapping the page from user processes.
325 * The garbage we just cleared may be mapped
326 * to a user process running on another cpu
327 * and this code is not running through normal
328 * I/O channels which handle SMP issues for
329 * us, so unmap page to synchronize all cpus.
331 * XXX should vm_pager_unmap_page() have
332 * dealt with this?
334 vm_page_protect(m, VM_PROT_NONE);
337 * Clear out partial-page dirty bits. This
338 * has the side effect of setting the valid
339 * bits, but that is ok. There are a bunch
340 * of places in the VM system where we expected
341 * m->dirty == VM_PAGE_BITS_ALL. The file EOF
342 * case is one of them. If the page is still
343 * partially dirty, make it fully dirty.
345 * NOTE: We do not clear out the valid
346 * bits. This would prevent bogus_page
347 * replacement from working properly.
349 * NOTE: We do not want to clear the dirty
350 * bit for a partial DEV_BSIZE'd truncation!
351 * This is DEV_BSIZE aligned!
353 vm_page_clear_dirty_beg_nonincl(m, base, size);
354 if (m->dirty != 0)
355 m->dirty = VM_PAGE_BITS_ALL;
356 vm_page_wakeup(m);
359 } else {
360 vp->v_filesize = nsize;
365 * Release a page busied for a getpages operation. The page may have become
366 * wired (typically due to being used by the buffer cache) or otherwise been
367 * soft-busied and cannot be freed in that case. A held page can still be
368 * freed.
370 void
371 vnode_pager_freepage(vm_page_t m)
373 if (m->busy || m->wire_count) {
374 vm_page_activate(m);
375 vm_page_wakeup(m);
376 } else {
377 vm_page_free(m);
382 * EOPNOTSUPP is no longer legal. For local media VFS's that do not
383 * implement their own VOP_GETPAGES, their VOP_GETPAGES should call to
384 * vnode_pager_generic_getpages() to implement the previous behaviour.
386 * All other FS's should use the bypass to get to the local media
387 * backing vp's VOP_GETPAGES.
389 static int
390 vnode_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess)
392 int rtval;
393 struct vnode *vp;
395 vp = object->handle;
396 rtval = VOP_GETPAGES(vp, mpp, PAGE_SIZE, 0, 0, seqaccess);
397 if (rtval == EOPNOTSUPP)
398 panic("vnode_pager: vfs's must implement vop_getpages\n");
399 return rtval;
403 * This is now called from local media FS's to operate against their
404 * own vnodes if they fail to implement VOP_GETPAGES.
406 * With all the caching local media devices do these days there is really
407 * very little point to attempting to restrict the I/O size to contiguous
408 * blocks on-disk, especially if our caller thinks we need all the specified
409 * pages. Just construct and issue a READ.
412 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *mpp, int bytecount,
413 int reqpage, int seqaccess)
415 struct iovec aiov;
416 struct uio auio;
417 off_t foff;
418 int error;
419 int count;
420 int i;
421 int ioflags;
424 * Do not do anything if the vnode is bad.
426 if (vp->v_mount == NULL)
427 return VM_PAGER_BAD;
430 * Calculate the number of pages. Since we are paging in whole
431 * pages, adjust bytecount to be an integral multiple of the page
432 * size. It will be clipped to the file EOF later on.
434 bytecount = round_page(bytecount);
435 count = bytecount / PAGE_SIZE;
438 * We could check m[reqpage]->valid here and shortcut the operation,
439 * but doing so breaks read-ahead. Instead assume that the VM
440 * system has already done at least the check, don't worry about
441 * any races, and issue the VOP_READ to allow read-ahead to function.
443 * This keeps the pipeline full for I/O bound sequentially scanned
444 * mmap()'s
446 /* don't shortcut */
449 * Discard pages past the file EOF. If the requested page is past
450 * the file EOF we just leave its valid bits set to 0, the caller
451 * expects to maintain ownership of the requested page. If the
452 * entire range is past file EOF discard everything and generate
453 * a pagein error.
455 foff = IDX_TO_OFF(mpp[0]->pindex);
456 if (foff >= vp->v_filesize) {
457 for (i = 0; i < count; i++) {
458 if (i != reqpage)
459 vnode_pager_freepage(mpp[i]);
461 return VM_PAGER_ERROR;
464 if (foff + bytecount > vp->v_filesize) {
465 bytecount = vp->v_filesize - foff;
466 i = round_page(bytecount) / PAGE_SIZE;
467 while (count > i) {
468 --count;
469 if (count != reqpage)
470 vnode_pager_freepage(mpp[count]);
475 * The size of the transfer is bytecount. bytecount will be an
476 * integral multiple of the page size unless it has been clipped
477 * to the file EOF. The transfer cannot exceed the file EOF.
479 * When dealing with real devices we must round-up to the device
480 * sector size.
482 if (vp->v_type == VBLK || vp->v_type == VCHR) {
483 int secmask = vp->v_rdev->si_bsize_phys - 1;
484 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1));
485 bytecount = (bytecount + secmask) & ~secmask;
489 * Severe hack to avoid deadlocks with the buffer cache
491 for (i = 0; i < count; ++i) {
492 vm_page_t mt = mpp[i];
494 vm_page_io_start(mt);
495 vm_page_wakeup(mt);
499 * Issue the I/O with some read-ahead if bytecount > PAGE_SIZE
501 ioflags = IO_VMIO;
502 if (seqaccess)
503 ioflags |= IO_SEQMAX << IO_SEQSHIFT;
505 aiov.iov_base = NULL;
506 aiov.iov_len = bytecount;
507 auio.uio_iov = &aiov;
508 auio.uio_iovcnt = 1;
509 auio.uio_offset = foff;
510 auio.uio_segflg = UIO_NOCOPY;
511 auio.uio_rw = UIO_READ;
512 auio.uio_resid = bytecount;
513 auio.uio_td = NULL;
514 mycpu->gd_cnt.v_vnodein++;
515 mycpu->gd_cnt.v_vnodepgsin += count;
517 error = VOP_READ(vp, &auio, ioflags, proc0.p_ucred);
520 * Severe hack to avoid deadlocks with the buffer cache
522 for (i = 0; i < count; ++i) {
523 vm_page_t mt = mpp[i];
525 while (vm_page_sleep_busy(mt, FALSE, "getpgs"))
527 vm_page_busy(mt);
528 vm_page_io_finish(mt);
532 * Calculate the actual number of bytes read and clean up the
533 * page list.
535 bytecount -= auio.uio_resid;
537 for (i = 0; i < count; ++i) {
538 vm_page_t mt = mpp[i];
540 if (i != reqpage) {
541 if (error == 0 && mt->valid) {
542 if (mt->flags & PG_WANTED)
543 vm_page_activate(mt);
544 else
545 vm_page_deactivate(mt);
546 vm_page_wakeup(mt);
547 } else {
548 vnode_pager_freepage(mt);
550 } else if (mt->valid == 0) {
551 if (error == 0) {
552 kprintf("page failed but no I/O error page %p object %p pindex %d\n", mt, mt->object, (int) mt->pindex);
553 /* whoops, something happened */
554 error = EINVAL;
556 } else if (mt->valid != VM_PAGE_BITS_ALL) {
558 * Zero-extend the requested page if necessary (if
559 * the filesystem is using a small block size).
561 vm_page_zero_invalid(mt, TRUE);
564 if (error) {
565 kprintf("vnode_pager_getpage: I/O read error\n");
567 return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
571 * EOPNOTSUPP is no longer legal. For local media VFS's that do not
572 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
573 * vnode_pager_generic_putpages() to implement the previous behaviour.
575 * Caller has already cleared the pmap modified bits, if any.
577 * All other FS's should use the bypass to get to the local media
578 * backing vp's VOP_PUTPAGES.
580 static void
581 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count,
582 boolean_t sync, int *rtvals)
584 int rtval;
585 struct vnode *vp;
586 int bytes = count * PAGE_SIZE;
589 * Force synchronous operation if we are extremely low on memory
590 * to prevent a low-memory deadlock. VOP operations often need to
591 * allocate more memory to initiate the I/O ( i.e. do a BMAP
592 * operation ). The swapper handles the case by limiting the amount
593 * of asynchronous I/O, but that sort of solution doesn't scale well
594 * for the vnode pager without a lot of work.
596 * Also, the backing vnode's iodone routine may not wake the pageout
597 * daemon up. This should be probably be addressed XXX.
600 if ((vmstats.v_free_count + vmstats.v_cache_count) < vmstats.v_pageout_free_min)
601 sync |= OBJPC_SYNC;
604 * Call device-specific putpages function
606 vp = object->handle;
607 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0);
608 if (rtval == EOPNOTSUPP) {
609 kprintf("vnode_pager: *** WARNING *** stale FS putpages\n");
610 rtval = vnode_pager_generic_putpages( vp, m, bytes, sync, rtvals);
616 * This is now called from local media FS's to operate against their
617 * own vnodes if they fail to implement VOP_PUTPAGES.
619 * This is typically called indirectly via the pageout daemon and
620 * clustering has already typically occured, so in general we ask the
621 * underlying filesystem to write the data out asynchronously rather
622 * then delayed.
625 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *m, int bytecount,
626 int flags, int *rtvals)
628 int i;
629 vm_object_t object;
630 int maxsize, ncount, count;
631 vm_ooffset_t poffset;
632 struct uio auio;
633 struct iovec aiov;
634 int error;
635 int ioflags;
637 object = vp->v_object;
638 count = bytecount / PAGE_SIZE;
640 for (i = 0; i < count; i++)
641 rtvals[i] = VM_PAGER_AGAIN;
643 if ((int) m[0]->pindex < 0) {
644 kprintf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n",
645 (long)m[0]->pindex, m[0]->dirty);
646 rtvals[0] = VM_PAGER_BAD;
647 return VM_PAGER_BAD;
650 maxsize = count * PAGE_SIZE;
651 ncount = count;
653 poffset = IDX_TO_OFF(m[0]->pindex);
656 * If the page-aligned write is larger then the actual file we
657 * have to invalidate pages occuring beyond the file EOF.
659 * If the file EOF resides in the middle of a page we still clear
660 * all of that page's dirty bits later on. If we didn't it would
661 * endlessly re-write.
663 * We do not under any circumstances truncate the valid bits, as
664 * this will screw up bogus page replacement.
666 * The caller has already read-protected the pages. The VFS must
667 * use the buffer cache to wrap the pages. The pages might not
668 * be immediately flushed by the buffer cache but once under its
669 * control the pages themselves can wind up being marked clean
670 * and their covering buffer cache buffer can be marked dirty.
672 if (poffset + maxsize > vp->v_filesize) {
673 if (poffset < vp->v_filesize) {
674 maxsize = vp->v_filesize - poffset;
675 ncount = btoc(maxsize);
676 } else {
677 maxsize = 0;
678 ncount = 0;
680 if (ncount < count) {
681 for (i = ncount; i < count; i++) {
682 rtvals[i] = VM_PAGER_BAD;
688 * pageouts are already clustered, use IO_ASYNC to force a bawrite()
689 * rather then a bdwrite() to prevent paging I/O from saturating
690 * the buffer cache. Dummy-up the sequential heuristic to cause
691 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set,
692 * the system decides how to cluster.
694 ioflags = IO_VMIO;
695 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL))
696 ioflags |= IO_SYNC;
697 else if ((flags & VM_PAGER_CLUSTER_OK) == 0)
698 ioflags |= IO_ASYNC;
699 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0;
700 ioflags |= IO_SEQMAX << IO_SEQSHIFT;
702 aiov.iov_base = (caddr_t) 0;
703 aiov.iov_len = maxsize;
704 auio.uio_iov = &aiov;
705 auio.uio_iovcnt = 1;
706 auio.uio_offset = poffset;
707 auio.uio_segflg = UIO_NOCOPY;
708 auio.uio_rw = UIO_WRITE;
709 auio.uio_resid = maxsize;
710 auio.uio_td = NULL;
711 error = VOP_WRITE(vp, &auio, ioflags, proc0.p_ucred);
712 mycpu->gd_cnt.v_vnodeout++;
713 mycpu->gd_cnt.v_vnodepgsout += ncount;
715 if (error) {
716 krateprintf(&vbadrate,
717 "vnode_pager_putpages: I/O error %d\n", error);
719 if (auio.uio_resid) {
720 krateprintf(&vresrate,
721 "vnode_pager_putpages: residual I/O %zd at %lu\n",
722 auio.uio_resid, (u_long)m[0]->pindex);
724 if (error == 0) {
725 for (i = 0; i < ncount; i++) {
726 rtvals[i] = VM_PAGER_OK;
727 vm_page_undirty(m[i]);
730 return rtvals[0];
733 struct vnode *
734 vnode_pager_lock(vm_object_t object)
736 struct thread *td = curthread; /* XXX */
737 int error;
739 for (; object != NULL; object = object->backing_object) {
740 if (object->type != OBJT_VNODE)
741 continue;
742 if (object->flags & OBJ_DEAD)
743 return NULL;
745 for (;;) {
746 struct vnode *vp = object->handle;
747 error = vget(vp, LK_SHARED | LK_RETRY | LK_CANRECURSE);
748 if (error == 0) {
749 if (object->handle != vp) {
750 vput(vp);
751 continue;
753 return (vp);
755 if ((object->flags & OBJ_DEAD) ||
756 (object->type != OBJT_VNODE)) {
757 return NULL;
759 kprintf("vnode_pager_lock: vp %p error %d lockstatus %d, retrying\n", vp, error, lockstatus(&vp->v_lock, td));
760 tsleep(object->handle, 0, "vnpgrl", hz);
763 return NULL;