2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * Rick Macklem at The University of Guelph.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * @(#)nfs_bio.c 8.9 (Berkeley) 3/30/95
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
38 #include <sys/param.h>
39 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/mount.h>
45 #include <sys/resourcevar.h>
46 #include <sys/signalvar.h>
47 #include <sys/vmmeter.h>
48 #include <sys/vnode.h>
51 #include <vm/vm_extern.h>
52 #include <vm/vm_page.h>
53 #include <vm/vm_object.h>
54 #include <vm/vm_pager.h>
55 #include <vm/vnode_pager.h>
57 #include <rpc/rpcclnt.h>
59 #include <nfs/rpcv2.h>
60 #include <nfs/nfsproto.h>
61 #include <nfsclient/nfs.h>
62 #include <nfsclient/nfsmount.h>
63 #include <nfsclient/nfsnode.h>
65 #include <nfs4client/nfs4.h>
67 static struct buf *nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size,
69 static int nfs_directio_write(struct vnode *vp, struct uio *uiop,
70 struct ucred *cred, int ioflag);
72 extern int nfs_directio_enable;
73 extern int nfs_directio_allow_mmap;
75 * Vnode op for VM getpages.
78 nfs_getpages(struct vop_getpages_args *ap)
80 int i, error, nextoff, size, toff, count, npages;
97 td = curthread; /* XXX */
98 cred = curthread->td_ucred; /* XXX */
99 nmp = VFSTONFS(vp->v_mount);
103 if ((object = vp->v_object) == NULL) {
104 printf("nfs_getpages: called with non-merged cache vnode??\n");
105 return VM_PAGER_ERROR;
108 if (!nfs_directio_allow_mmap && (np->n_flag & NNONCACHE) &&
109 (vp->v_type == VREG)) {
110 printf("nfs_getpages: called on non-cacheable vnode??\n");
111 return VM_PAGER_ERROR;
114 if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
115 (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
116 /* We'll never get here for v4, because we always have fsinfo */
117 (void)nfs_fsinfo(nmp, vp, cred, td);
120 npages = btoc(count);
123 * If the requested page is partially valid, just return it and
124 * allow the pager to zero-out the blanks. Partially valid pages
125 * can only occur at the file EOF.
129 vm_page_t m = pages[ap->a_reqpage];
131 VM_OBJECT_LOCK(object);
132 vm_page_lock_queues();
134 /* handled by vm_fault now */
135 /* vm_page_zero_invalid(m, TRUE); */
136 for (i = 0; i < npages; ++i) {
137 if (i != ap->a_reqpage)
138 vm_page_free(pages[i]);
140 vm_page_unlock_queues();
141 VM_OBJECT_UNLOCK(object);
144 vm_page_unlock_queues();
145 VM_OBJECT_UNLOCK(object);
149 * We use only the kva address for the buffer, but this is extremely
150 * convienient and fast.
152 bp = getpbuf(&nfs_pbuf_freecnt);
154 kva = (vm_offset_t) bp->b_data;
155 pmap_qenter(kva, pages, npages);
157 cnt.v_vnodepgsin += npages;
159 iov.iov_base = (caddr_t) kva;
163 uio.uio_offset = IDX_TO_OFF(pages[0]->pindex);
164 uio.uio_resid = count;
165 uio.uio_segflg = UIO_SYSSPACE;
166 uio.uio_rw = UIO_READ;
169 error = (nmp->nm_rpcops->nr_readrpc)(vp, &uio, cred);
170 pmap_qremove(kva, npages);
172 relpbuf(bp, &nfs_pbuf_freecnt);
174 if (error && (uio.uio_resid == count)) {
175 printf("nfs_getpages: error %d\n", error);
176 VM_OBJECT_LOCK(object);
177 vm_page_lock_queues();
178 for (i = 0; i < npages; ++i) {
179 if (i != ap->a_reqpage)
180 vm_page_free(pages[i]);
182 vm_page_unlock_queues();
183 VM_OBJECT_UNLOCK(object);
184 return VM_PAGER_ERROR;
188 * Calculate the number of bytes read and validate only that number
189 * of bytes. Note that due to pending writes, size may be 0. This
190 * does not mean that the remaining data is invalid!
193 size = count - uio.uio_resid;
194 VM_OBJECT_LOCK(object);
195 vm_page_lock_queues();
196 for (i = 0, toff = 0; i < npages; i++, toff = nextoff) {
198 nextoff = toff + PAGE_SIZE;
201 if (nextoff <= size) {
203 * Read operation filled an entire page
205 m->valid = VM_PAGE_BITS_ALL;
207 } else if (size > toff) {
209 * Read operation filled a partial page.
212 vm_page_set_validclean(m, 0, size - toff);
213 /* handled by vm_fault now */
214 /* vm_page_zero_invalid(m, TRUE); */
217 * Read operation was short. If no error occured
218 * we may have hit a zero-fill section. We simply
219 * leave valid set to 0.
223 if (i != ap->a_reqpage) {
225 * Whether or not to leave the page activated is up in
226 * the air, but we should put the page on a page queue
227 * somewhere (it already is in the object). Result:
228 * It appears that emperical results show that
229 * deactivating pages is best.
233 * Just in case someone was asking for this page we
234 * now tell them that it is ok to use.
237 if (m->flags & PG_WANTED)
240 vm_page_deactivate(m);
247 vm_page_unlock_queues();
248 VM_OBJECT_UNLOCK(object);
253 * Vnode op for VM putpages.
256 nfs_putpages(struct vop_putpages_args *ap)
262 int iomode, must_commit, i, error, npages, count;
268 struct nfsmount *nmp;
276 td = curthread; /* XXX */
277 cred = curthread->td_ucred; /* XXX */
278 nmp = VFSTONFS(vp->v_mount);
281 rtvals = ap->a_rtvals;
282 npages = btoc(count);
283 offset = IDX_TO_OFF(pages[0]->pindex);
285 if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
286 (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
287 (void)nfs_fsinfo(nmp, vp, cred, td);
290 if (!nfs_directio_allow_mmap && (np->n_flag & NNONCACHE) &&
291 (vp->v_type == VREG))
292 printf("nfs_putpages: called on noncache-able vnode??\n");
294 for (i = 0; i < npages; i++)
295 rtvals[i] = VM_PAGER_AGAIN;
298 * When putting pages, do not extend file past EOF.
301 if (offset + count > np->n_size) {
302 count = np->n_size - offset;
308 * We use only the kva address for the buffer, but this is extremely
309 * convienient and fast.
311 bp = getpbuf(&nfs_pbuf_freecnt);
313 kva = (vm_offset_t) bp->b_data;
314 pmap_qenter(kva, pages, npages);
316 cnt.v_vnodepgsout += count;
318 iov.iov_base = (caddr_t) kva;
322 uio.uio_offset = offset;
323 uio.uio_resid = count;
324 uio.uio_segflg = UIO_SYSSPACE;
325 uio.uio_rw = UIO_WRITE;
328 if ((ap->a_sync & VM_PAGER_PUT_SYNC) == 0)
329 iomode = NFSV3WRITE_UNSTABLE;
331 iomode = NFSV3WRITE_FILESYNC;
333 error = (nmp->nm_rpcops->nr_writerpc)(vp, &uio, cred, &iomode, &must_commit);
335 pmap_qremove(kva, npages);
336 relpbuf(bp, &nfs_pbuf_freecnt);
339 int nwritten = round_page(count - uio.uio_resid) / PAGE_SIZE;
340 for (i = 0; i < nwritten; i++) {
341 rtvals[i] = VM_PAGER_OK;
342 vm_page_undirty(pages[i]);
345 nfs_clearcommit(vp->v_mount);
352 * Vnode op for read using bio
355 nfs_bioread(struct vnode *vp, struct uio *uio, int ioflag, struct ucred *cred)
357 struct nfsnode *np = VTONFS(vp);
359 struct buf *bp = 0, *rabp;
362 struct nfsmount *nmp = VFSTONFS(vp->v_mount);
366 int nra, error = 0, n = 0, on = 0;
369 if (uio->uio_rw != UIO_READ)
370 panic("nfs_read mode");
372 if (uio->uio_resid == 0)
374 if (uio->uio_offset < 0) /* XXX VDIR cookies can be negative */
378 if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
379 (nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
380 (void)nfs_fsinfo(nmp, vp, cred, td);
381 if (vp->v_type != VDIR &&
382 (uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
385 if (nfs_directio_enable && (ioflag & IO_DIRECT) && (vp->v_type == VREG))
386 /* No caching/ no readaheads. Just read data into the user buffer */
387 return nfs_readrpc(vp, uio, cred);
389 biosize = vp->v_mount->mnt_stat.f_iosize;
390 seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
392 * For nfs, cache consistency can only be maintained approximately.
393 * Although RFC1094 does not specify the criteria, the following is
394 * believed to be compatible with the reference port.
396 * If the file's modify time on the server has changed since the
397 * last read rpc or you have written to the file,
398 * you may have lost data cache consistency with the
399 * server, so flush all of the file's data out of the cache.
400 * Then force a getattr rpc to ensure that you have up to date
402 * NB: This implies that cache data can be read when up to
403 * NFS_ATTRTIMEO seconds out of date. If you find that you need current
404 * attributes this could be forced by setting n_attrstamp to 0 before
405 * the VOP_GETATTR() call.
407 if (np->n_flag & NMODIFIED) {
408 if (vp->v_type != VREG) {
409 if (vp->v_type != VDIR)
410 panic("nfs: bioread, not dir");
411 (nmp->nm_rpcops->nr_invaldir)(vp);
412 error = nfs_vinvalbuf(vp, V_SAVE, td, 1);
417 error = VOP_GETATTR(vp, &vattr, cred, td);
420 np->n_mtime = vattr.va_mtime;
422 error = VOP_GETATTR(vp, &vattr, cred, td);
425 if ((np->n_flag & NSIZECHANGED)
426 || (NFS_TIMESPEC_COMPARE(&np->n_mtime, &vattr.va_mtime))) {
427 if (vp->v_type == VDIR)
428 (nmp->nm_rpcops->nr_invaldir)(vp);
429 error = nfs_vinvalbuf(vp, V_SAVE, td, 1);
432 np->n_mtime = vattr.va_mtime;
433 np->n_flag &= ~NSIZECHANGED;
437 switch (vp->v_type) {
439 nfsstats.biocache_reads++;
440 lbn = uio->uio_offset / biosize;
441 on = uio->uio_offset & (biosize - 1);
444 * Start the read ahead(s), as required.
445 * The readahead is kicked off only if sequential access
446 * is detected, based on the readahead hint (ra_expect_lbn).
448 if (nmp->nm_readahead > 0 && np->ra_expect_lbn == lbn) {
449 for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
450 (off_t)(lbn + 1 + nra) * biosize < np->n_size; nra++) {
451 rabn = lbn + 1 + nra;
452 if (incore(&vp->v_bufobj, rabn) == NULL) {
453 rabp = nfs_getcacheblk(vp, rabn, biosize, td);
455 error = nfs_sigintr(nmp, NULL, td);
456 return (error ? error : EINTR);
458 if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
459 rabp->b_flags |= B_ASYNC;
460 rabp->b_iocmd = BIO_READ;
461 vfs_busy_pages(rabp, 0);
462 if (nfs_asyncio(nmp, rabp, cred, td)) {
463 rabp->b_flags |= B_INVAL;
464 rabp->b_ioflags |= BIO_ERROR;
465 vfs_unbusy_pages(rabp);
474 np->ra_expect_lbn = lbn + 1;
478 * Obtain the buffer cache block. Figure out the buffer size
479 * when we are at EOF. If we are modifying the size of the
480 * buffer based on an EOF condition we need to hold
481 * nfs_rslock() through obtaining the buffer to prevent
482 * a potential writer-appender from messing with n_size.
483 * Otherwise we may accidently truncate the buffer and
486 * Note that bcount is *not* DEV_BSIZE aligned.
491 if ((off_t)lbn * biosize >= np->n_size) {
493 } else if ((off_t)(lbn + 1) * biosize > np->n_size) {
494 bcount = np->n_size - (off_t)lbn * biosize;
496 if (bcount != biosize) {
497 switch(nfs_rslock(np, td)) {
512 bp = nfs_getcacheblk(vp, lbn, bcount, td);
514 if (bcount != biosize)
515 nfs_rsunlock(np, td);
517 error = nfs_sigintr(nmp, NULL, td);
518 return (error ? error : EINTR);
522 * If B_CACHE is not set, we must issue the read. If this
523 * fails, we return an error.
526 if ((bp->b_flags & B_CACHE) == 0) {
527 bp->b_iocmd = BIO_READ;
528 vfs_busy_pages(bp, 0);
529 error = nfs_doio(vp, bp, cred, td);
537 * on is the offset into the current bp. Figure out how many
538 * bytes we can copy out of the bp. Note that bcount is
539 * NOT DEV_BSIZE aligned.
541 * Then figure out how many bytes we can copy into the uio.
546 n = min((unsigned)(bcount - on), uio->uio_resid);
549 nfsstats.biocache_readlinks++;
550 bp = nfs_getcacheblk(vp, (daddr_t)0, NFS_MAXPATHLEN, td);
552 error = nfs_sigintr(nmp, NULL, td);
553 return (error ? error : EINTR);
555 if ((bp->b_flags & B_CACHE) == 0) {
556 bp->b_iocmd = BIO_READ;
557 vfs_busy_pages(bp, 0);
558 error = nfs_doio(vp, bp, cred, td);
560 bp->b_ioflags |= BIO_ERROR;
565 n = min(uio->uio_resid, NFS_MAXPATHLEN - bp->b_resid);
569 nfsstats.biocache_readdirs++;
570 if (np->n_direofoffset
571 && uio->uio_offset >= np->n_direofoffset) {
574 lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
575 on = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
576 bp = nfs_getcacheblk(vp, lbn, NFS_DIRBLKSIZ, td);
578 error = nfs_sigintr(nmp, NULL, td);
579 return (error ? error : EINTR);
581 if ((bp->b_flags & B_CACHE) == 0) {
582 bp->b_iocmd = BIO_READ;
583 vfs_busy_pages(bp, 0);
584 error = nfs_doio(vp, bp, cred, td);
588 while (error == NFSERR_BAD_COOKIE) {
589 (nmp->nm_rpcops->nr_invaldir)(vp);
590 error = nfs_vinvalbuf(vp, 0, td, 1);
592 * Yuck! The directory has been modified on the
593 * server. The only way to get the block is by
594 * reading from the beginning to get all the
597 * Leave the last bp intact unless there is an error.
598 * Loop back up to the while if the error is another
599 * NFSERR_BAD_COOKIE (double yuch!).
601 for (i = 0; i <= lbn && !error; i++) {
602 if (np->n_direofoffset
603 && (i * NFS_DIRBLKSIZ) >= np->n_direofoffset)
605 bp = nfs_getcacheblk(vp, i, NFS_DIRBLKSIZ, td);
607 error = nfs_sigintr(nmp, NULL, td);
608 return (error ? error : EINTR);
610 if ((bp->b_flags & B_CACHE) == 0) {
611 bp->b_iocmd = BIO_READ;
612 vfs_busy_pages(bp, 0);
613 error = nfs_doio(vp, bp, cred, td);
615 * no error + B_INVAL == directory EOF,
618 if (error == 0 && (bp->b_flags & B_INVAL))
622 * An error will throw away the block and the
623 * for loop will break out. If no error and this
624 * is not the block we want, we throw away the
625 * block and go for the next one via the for loop.
627 if (error || i < lbn)
632 * The above while is repeated if we hit another cookie
633 * error. If we hit an error and it wasn't a cookie error,
641 * If not eof and read aheads are enabled, start one.
642 * (You need the current block first, so that you have the
643 * directory offset cookie of the next block.)
645 if (nmp->nm_readahead > 0 &&
646 (bp->b_flags & B_INVAL) == 0 &&
647 (np->n_direofoffset == 0 ||
648 (lbn + 1) * NFS_DIRBLKSIZ < np->n_direofoffset) &&
649 incore(&vp->v_bufobj, lbn + 1) == NULL) {
650 rabp = nfs_getcacheblk(vp, lbn + 1, NFS_DIRBLKSIZ, td);
652 if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
653 rabp->b_flags |= B_ASYNC;
654 rabp->b_iocmd = BIO_READ;
655 vfs_busy_pages(rabp, 0);
656 if (nfs_asyncio(nmp, rabp, cred, td)) {
657 rabp->b_flags |= B_INVAL;
658 rabp->b_ioflags |= BIO_ERROR;
659 vfs_unbusy_pages(rabp);
668 * Unlike VREG files, whos buffer size ( bp->b_bcount ) is
669 * chopped for the EOF condition, we cannot tell how large
670 * NFS directories are going to be until we hit EOF. So
671 * an NFS directory buffer is *not* chopped to its EOF. Now,
672 * it just so happens that b_resid will effectively chop it
673 * to EOF. *BUT* this information is lost if the buffer goes
674 * away and is reconstituted into a B_CACHE state ( due to
675 * being VMIO ) later. So we keep track of the directory eof
676 * in np->n_direofoffset and chop it off as an extra step
679 n = lmin(uio->uio_resid, NFS_DIRBLKSIZ - bp->b_resid - on);
680 if (np->n_direofoffset && n > np->n_direofoffset - uio->uio_offset)
681 n = np->n_direofoffset - uio->uio_offset;
684 printf(" nfs_bioread: type %x unexpected\n", vp->v_type);
689 error = uiomove(bp->b_data + on, (int)n, uio);
691 switch (vp->v_type) {
700 printf(" nfs_bioread: type %x unexpected\n", vp->v_type);
703 } while (error == 0 && uio->uio_resid > 0 && n > 0);
708 * The NFS write path cannot handle iovecs with len > 1. So we need to
709 * break up iovecs accordingly (restricting them to wsize).
710 * For the SYNC case, we can do this with 1 copy (user buffer -> mbuf).
711 * For the ASYNC case, 2 copies are needed. The first a copy from the
712 * user buffer to a staging buffer and then a second copy from the staging
713 * buffer to mbufs. This can be optimized by copying from the user buffer
714 * directly into mbufs and passing the chain down, but that requires a
715 * fair amount of re-working of the relevant codepaths (and can be done
719 nfs_directio_write(vp, uiop, cred, ioflag)
726 struct nfsmount *nmp = VFSTONFS(vp->v_mount);
727 struct thread *td = uiop->uio_td;
730 if (ioflag & IO_SYNC) {
731 int iomode, must_commit;
735 while (uiop->uio_resid > 0) {
736 size = min(uiop->uio_resid, nmp->nm_wsize);
737 size = min(uiop->uio_iov->iov_len, size);
738 iov.iov_base = uiop->uio_iov->iov_base;
742 uio.uio_offset = uiop->uio_offset;
743 uio.uio_resid = size;
744 uio.uio_segflg = UIO_USERSPACE;
745 uio.uio_rw = UIO_WRITE;
747 iomode = NFSV3WRITE_FILESYNC;
748 error = (nmp->nm_rpcops->nr_writerpc)(vp, &uio, cred,
749 &iomode, &must_commit);
750 KASSERT((must_commit == 0),
751 ("nfs_directio_write: Did not commit write"));
754 uiop->uio_offset += size;
755 uiop->uio_resid -= size;
756 if (uiop->uio_iov->iov_len <= size) {
760 uiop->uio_iov->iov_base =
761 (char *)uiop->uio_iov->iov_base + size;
762 uiop->uio_iov->iov_len -= size;
771 * Break up the write into blocksize chunks and hand these
772 * over to nfsiod's for write back.
773 * Unfortunately, this incurs a copy of the data. Since
774 * the user could modify the buffer before the write is
777 * The obvious optimization here is that one of the 2 copies
778 * in the async write path can be eliminated by copying the
779 * data here directly into mbufs and passing the mbuf chain
780 * down. But that will require a fair amount of re-working
781 * of the code and can be done if there's enough interest
782 * in NFS directio access.
784 while (uiop->uio_resid > 0) {
785 size = min(uiop->uio_resid, nmp->nm_wsize);
786 size = min(uiop->uio_iov->iov_len, size);
787 bp = getpbuf(&nfs_pbuf_freecnt);
788 t_uio = malloc(sizeof(struct uio), M_NFSDIRECTIO, M_WAITOK);
789 t_iov = malloc(sizeof(struct iovec), M_NFSDIRECTIO, M_WAITOK);
790 t_iov->iov_base = malloc(size, M_NFSDIRECTIO, M_WAITOK);
791 t_iov->iov_len = size;
792 t_uio->uio_iov = t_iov;
793 t_uio->uio_iovcnt = 1;
794 t_uio->uio_offset = uiop->uio_offset;
795 t_uio->uio_resid = size;
796 t_uio->uio_segflg = UIO_SYSSPACE;
797 t_uio->uio_rw = UIO_WRITE;
799 bcopy(uiop->uio_iov->iov_base, t_iov->iov_base, size);
800 bp->b_flags |= B_DIRECT;
801 bp->b_iocmd = BIO_WRITE;
802 if (cred != NOCRED) {
806 bp->b_wcred = NOCRED;
807 bp->b_caller1 = (void *)t_uio;
810 error = nfs_asyncio(nmp, bp, NOCRED, td);
812 free(t_iov->iov_base, M_NFSDIRECTIO);
813 free(t_iov, M_NFSDIRECTIO);
814 free(t_uio, M_NFSDIRECTIO);
817 relpbuf(bp, &nfs_pbuf_freecnt);
822 uiop->uio_offset += size;
823 uiop->uio_resid -= size;
824 if (uiop->uio_iov->iov_len <= size) {
828 uiop->uio_iov->iov_base =
829 (char *)uiop->uio_iov->iov_base + size;
830 uiop->uio_iov->iov_len -= size;
838 * Vnode op for write using bio
841 nfs_write(struct vop_write_args *ap)
844 struct uio *uio = ap->a_uio;
845 struct thread *td = uio->uio_td;
846 struct vnode *vp = ap->a_vp;
847 struct nfsnode *np = VTONFS(vp);
848 struct ucred *cred = ap->a_cred;
849 int ioflag = ap->a_ioflag;
852 struct nfsmount *nmp = VFSTONFS(vp->v_mount);
855 int n, on, error = 0;
857 struct proc *p = td?td->td_proc:NULL;
862 if (uio->uio_rw != UIO_WRITE)
863 panic("nfs_write mode");
864 if (uio->uio_segflg == UIO_USERSPACE && uio->uio_td != curthread)
865 panic("nfs_write proc");
867 if (vp->v_type != VREG)
869 if (np->n_flag & NWRITEERR) {
870 np->n_flag &= ~NWRITEERR;
871 return (np->n_error);
873 if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
874 (nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
875 (void)nfs_fsinfo(nmp, vp, cred, td);
878 * Synchronously flush pending buffers if we are in synchronous
879 * mode or if we are appending.
881 if (ioflag & (IO_APPEND | IO_SYNC)) {
882 if (np->n_flag & NMODIFIED) {
884 error = nfs_vinvalbuf(vp, V_SAVE, td, 1);
891 * If IO_APPEND then load uio_offset. We restart here if we cannot
892 * get the append lock.
895 if (ioflag & IO_APPEND) {
897 error = VOP_GETATTR(vp, &vattr, cred, td);
900 uio->uio_offset = np->n_size;
903 if (uio->uio_offset < 0)
905 if ((uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
907 if (uio->uio_resid == 0)
910 if (nfs_directio_enable && (ioflag & IO_DIRECT) && vp->v_type == VREG)
911 return nfs_directio_write(vp, uio, cred, ioflag);
914 * We need to obtain the rslock if we intend to modify np->n_size
915 * in order to guarentee the append point with multiple contending
916 * writers, to guarentee that no other appenders modify n_size
917 * while we are trying to obtain a truncated buffer (i.e. to avoid
918 * accidently truncating data written by another appender due to
919 * the race), and to ensure that the buffer is populated prior to
920 * our extending of the file. We hold rslock through the entire
923 * Note that we do not synchronize the case where someone truncates
924 * the file while we are appending to it because attempting to lock
925 * this case may deadlock other parts of the system unexpectedly.
927 if ((ioflag & IO_APPEND) ||
928 uio->uio_offset + uio->uio_resid > np->n_size) {
929 switch(nfs_rslock(np, td)) {
946 * Maybe this should be above the vnode op call, but so long as
947 * file servers have no limits, i don't think it matters
951 if (uio->uio_offset + uio->uio_resid >
952 lim_cur(p, RLIMIT_FSIZE)) {
956 nfs_rsunlock(np, td);
962 biosize = vp->v_mount->mnt_stat.f_iosize;
965 nfsstats.biocache_writes++;
966 lbn = uio->uio_offset / biosize;
967 on = uio->uio_offset & (biosize-1);
968 n = min((unsigned)(biosize - on), uio->uio_resid);
971 * Handle direct append and file extension cases, calculate
972 * unaligned buffer size.
975 if (uio->uio_offset == np->n_size && n) {
977 * Get the buffer (in its pre-append state to maintain
978 * B_CACHE if it was previously set). Resize the
979 * nfsnode after we have locked the buffer to prevent
980 * readers from reading garbage.
983 bp = nfs_getcacheblk(vp, lbn, bcount, td);
988 np->n_size = uio->uio_offset + n;
989 np->n_flag |= NMODIFIED;
990 vnode_pager_setsize(vp, np->n_size);
992 save = bp->b_flags & B_CACHE;
994 allocbuf(bp, bcount);
999 * Obtain the locked cache block first, and then
1000 * adjust the file's size as appropriate.
1003 if ((off_t)lbn * biosize + bcount < np->n_size) {
1004 if ((off_t)(lbn + 1) * biosize < np->n_size)
1007 bcount = np->n_size - (off_t)lbn * biosize;
1009 bp = nfs_getcacheblk(vp, lbn, bcount, td);
1010 if (uio->uio_offset + n > np->n_size) {
1011 np->n_size = uio->uio_offset + n;
1012 np->n_flag |= NMODIFIED;
1013 vnode_pager_setsize(vp, np->n_size);
1018 error = nfs_sigintr(nmp, NULL, td);
1025 * Issue a READ if B_CACHE is not set. In special-append
1026 * mode, B_CACHE is based on the buffer prior to the write
1027 * op and is typically set, avoiding the read. If a read
1028 * is required in special append mode, the server will
1029 * probably send us a short-read since we extended the file
1030 * on our end, resulting in b_resid == 0 and, thusly,
1031 * B_CACHE getting set.
1033 * We can also avoid issuing the read if the write covers
1034 * the entire buffer. We have to make sure the buffer state
1035 * is reasonable in this case since we will not be initiating
1036 * I/O. See the comments in kern/vfs_bio.c's getblk() for
1039 * B_CACHE may also be set due to the buffer being cached
1043 if (on == 0 && n == bcount) {
1044 bp->b_flags |= B_CACHE;
1045 bp->b_flags &= ~B_INVAL;
1046 bp->b_ioflags &= ~BIO_ERROR;
1049 if ((bp->b_flags & B_CACHE) == 0) {
1050 bp->b_iocmd = BIO_READ;
1051 vfs_busy_pages(bp, 0);
1052 error = nfs_doio(vp, bp, cred, td);
1059 error = nfs_sigintr(nmp, NULL, td);
1064 if (bp->b_wcred == NOCRED)
1065 bp->b_wcred = crhold(cred);
1066 np->n_flag |= NMODIFIED;
1069 * If dirtyend exceeds file size, chop it down. This should
1070 * not normally occur but there is an append race where it
1071 * might occur XXX, so we log it.
1073 * If the chopping creates a reverse-indexed or degenerate
1074 * situation with dirtyoff/end, we 0 both of them.
1077 if (bp->b_dirtyend > bcount) {
1078 printf("NFS append race @%lx:%d\n",
1079 (long)bp->b_blkno * DEV_BSIZE,
1080 bp->b_dirtyend - bcount);
1081 bp->b_dirtyend = bcount;
1084 if (bp->b_dirtyoff >= bp->b_dirtyend)
1085 bp->b_dirtyoff = bp->b_dirtyend = 0;
1088 * If the new write will leave a contiguous dirty
1089 * area, just update the b_dirtyoff and b_dirtyend,
1090 * otherwise force a write rpc of the old dirty area.
1092 * While it is possible to merge discontiguous writes due to
1093 * our having a B_CACHE buffer ( and thus valid read data
1094 * for the hole), we don't because it could lead to
1095 * significant cache coherency problems with multiple clients,
1096 * especially if locking is implemented later on.
1098 * as an optimization we could theoretically maintain
1099 * a linked list of discontinuous areas, but we would still
1100 * have to commit them separately so there isn't much
1101 * advantage to it except perhaps a bit of asynchronization.
1104 if (bp->b_dirtyend > 0 &&
1105 (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) {
1106 if (bwrite(bp) == EINTR) {
1113 error = uiomove((char *)bp->b_data + on, n, uio);
1116 * Since this block is being modified, it must be written
1117 * again and not just committed. Since write clustering does
1118 * not work for the stage 1 data write, only the stage 2
1119 * commit rpc, we have to clear B_CLUSTEROK as well.
1121 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1124 bp->b_ioflags |= BIO_ERROR;
1130 * Only update dirtyoff/dirtyend if not a degenerate
1134 if (bp->b_dirtyend > 0) {
1135 bp->b_dirtyoff = min(on, bp->b_dirtyoff);
1136 bp->b_dirtyend = max((on + n), bp->b_dirtyend);
1138 bp->b_dirtyoff = on;
1139 bp->b_dirtyend = on + n;
1141 vfs_bio_set_validclean(bp, on, n);
1145 * If IO_SYNC do bwrite().
1147 * IO_INVAL appears to be unused. The idea appears to be
1148 * to turn off caching in this case. Very odd. XXX
1150 if ((ioflag & IO_SYNC)) {
1151 if (ioflag & IO_INVAL)
1152 bp->b_flags |= B_NOCACHE;
1156 } else if ((n + on) == biosize) {
1157 bp->b_flags |= B_ASYNC;
1158 (void) (nmp->nm_rpcops->nr_writebp)(bp, 0, 0);
1162 } while (uio->uio_resid > 0 && n > 0);
1165 nfs_rsunlock(np, td);
1171 * Get an nfs cache block.
1173 * Allocate a new one if the block isn't currently in the cache
1174 * and return the block marked busy. If the calling process is
1175 * interrupted by a signal for an interruptible mount point, return
1178 * The caller must carefully deal with the possible B_INVAL state of
1179 * the buffer. nfs_doio() clears B_INVAL (and nfs_asyncio() clears it
1180 * indirectly), so synchronous reads can be issued without worrying about
1181 * the B_INVAL state. We have to be a little more careful when dealing
1182 * with writes (see comments in nfs_write()) when extending a file past
1186 nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size, struct thread *td)
1190 struct nfsmount *nmp;
1195 if (nmp->nm_flag & NFSMNT_INT) {
1198 nfs_set_sigmask(td, &oldset);
1199 bp = getblk(vp, bn, size, PCATCH, 0, 0);
1200 nfs_restore_sigmask(td, &oldset);
1201 while (bp == NULL) {
1202 if (nfs_sigintr(nmp, NULL, td))
1204 bp = getblk(vp, bn, size, 0, 2 * hz, 0);
1207 bp = getblk(vp, bn, size, 0, 0, 0);
1210 if (vp->v_type == VREG) {
1213 biosize = mp->mnt_stat.f_iosize;
1214 bp->b_blkno = bn * (biosize / DEV_BSIZE);
1220 * Flush and invalidate all dirty buffers. If another process is already
1221 * doing the flush, just wait for completion.
1224 nfs_vinvalbuf(struct vnode *vp, int flags, struct thread *td, int intrflg)
1226 struct nfsnode *np = VTONFS(vp);
1227 struct nfsmount *nmp = VFSTONFS(vp->v_mount);
1228 int error = 0, slpflag, slptimeo;
1231 ASSERT_VOP_LOCKED(vp, "nfs_vinvalbuf");
1234 * XXX This check stops us from needlessly doing a vinvalbuf when
1235 * being called through vclean(). It is not clear that this is
1238 if (vp->v_iflag & VI_DOOMED)
1241 if ((nmp->nm_flag & NFSMNT_INT) == 0)
1251 if ((old_lock = VOP_ISLOCKED(vp, td)) != LK_EXCLUSIVE) {
1252 if (old_lock == LK_SHARED) {
1253 /* Upgrade to exclusive lock, this might block */
1254 vn_lock(vp, LK_UPGRADE | LK_RETRY, td);
1256 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
1261 * Now, flush as required.
1263 error = vinvalbuf(vp, flags, td, slpflag, 0);
1265 if (intrflg && (error = nfs_sigintr(nmp, NULL, td)))
1267 error = vinvalbuf(vp, flags, td, 0, slptimeo);
1269 np->n_flag &= ~NMODIFIED;
1271 if (old_lock != LK_EXCLUSIVE) {
1272 if (old_lock == LK_SHARED) {
1273 /* Downgrade from exclusive lock, this might block */
1274 vn_lock(vp, LK_DOWNGRADE, td);
1276 VOP_UNLOCK(vp, 0, td);
1283 * Initiate asynchronous I/O. Return an error if no nfsiods are available.
1284 * This is mainly to avoid queueing async I/O requests when the nfsiods
1285 * are all hung on a dead server.
1287 * Note: nfs_asyncio() does not clear (BIO_ERROR|B_INVAL) but when the bp
1288 * is eventually dequeued by the async daemon, nfs_doio() *will*.
1291 nfs_asyncio(struct nfsmount *nmp, struct buf *bp, struct ucred *cred, struct thread *td)
1300 * Commits are usually short and sweet so lets save some cpu and
1301 * leave the async daemons for more important rpc's (such as reads
1304 if (bp->b_iocmd == BIO_WRITE && (bp->b_flags & B_NEEDCOMMIT) &&
1305 (nmp->nm_bufqiods > nfs_numasync / 2)) {
1310 if (nmp->nm_flag & NFSMNT_INT)
1315 * Find a free iod to process this request.
1317 for (iod = 0; iod < nfs_numasync; iod++)
1318 if (nfs_iodwant[iod]) {
1324 * Try to create one if none are free.
1327 iod = nfs_nfsiodnew();
1334 * Found one, so wake it up and tell it which
1337 NFS_DPF(ASYNCIO, ("nfs_asyncio: waking iod %d for mount %p\n",
1339 nfs_iodwant[iod] = NULL;
1340 nfs_iodmount[iod] = nmp;
1342 wakeup(&nfs_iodwant[iod]);
1346 * If none are free, we may already have an iod working on this mount
1347 * point. If so, it will process our request.
1350 if (nmp->nm_bufqiods > 0) {
1352 ("nfs_asyncio: %d iods are already processing mount %p\n",
1353 nmp->nm_bufqiods, nmp));
1359 * If we have an iod which can process the request, then queue
1364 * Ensure that the queue never grows too large. We still want
1365 * to asynchronize so we block rather then return EIO.
1367 while (nmp->nm_bufqlen >= 2*nfs_numasync) {
1369 ("nfs_asyncio: waiting for mount %p queue to drain\n", nmp));
1370 nmp->nm_bufqwant = TRUE;
1371 error = nfs_tsleep(td, &nmp->nm_bufq, slpflag | PRIBIO,
1372 "nfsaio", slptimeo);
1374 error2 = nfs_sigintr(nmp, NULL, td);
1377 if (slpflag == PCATCH) {
1383 * We might have lost our iod while sleeping,
1384 * so check and loop if nescessary.
1386 if (nmp->nm_bufqiods == 0) {
1388 ("nfs_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
1393 if (bp->b_iocmd == BIO_READ) {
1394 if (bp->b_rcred == NOCRED && cred != NOCRED)
1395 bp->b_rcred = crhold(cred);
1397 if (bp->b_wcred == NOCRED && cred != NOCRED)
1398 bp->b_wcred = crhold(cred);
1401 if (bp->b_flags & B_REMFREE)
1404 TAILQ_INSERT_TAIL(&nmp->nm_bufq, bp, b_freelist);
1410 * All the iods are busy on other mounts, so return EIO to
1411 * force the caller to process the i/o synchronously.
1413 NFS_DPF(ASYNCIO, ("nfs_asyncio: no iods available, i/o is synchronous\n"));
1418 nfs_doio_directwrite(struct buf *bp)
1420 int iomode, must_commit;
1421 struct uio *uiop = (struct uio *)bp->b_caller1;
1422 char *iov_base = uiop->uio_iov->iov_base;
1423 struct nfsmount *nmp = VFSTONFS(bp->b_vp->v_mount);
1425 iomode = NFSV3WRITE_FILESYNC;
1426 uiop->uio_td = NULL; /* NULL since we're in nfsiod */
1427 (nmp->nm_rpcops->nr_writerpc)(bp->b_vp, uiop, bp->b_wcred, &iomode, &must_commit);
1428 KASSERT((must_commit == 0), ("nfs_doio_directwrite: Did not commit write"));
1429 free(iov_base, M_NFSDIRECTIO);
1430 free(uiop->uio_iov, M_NFSDIRECTIO);
1431 free(uiop, M_NFSDIRECTIO);
1434 relpbuf(bp, &nfs_pbuf_freecnt);
1438 * Do an I/O operation to/from a cache block. This may be called
1439 * synchronously or from an nfsiod.
1442 nfs_doio(struct vnode *vp, struct buf *bp, struct ucred *cr, struct thread *td)
1446 struct nfsmount *nmp;
1447 int error = 0, iomode, must_commit = 0;
1450 struct proc *p = td ? td->td_proc : NULL;
1453 nmp = VFSTONFS(vp->v_mount);
1455 uiop->uio_iov = &io;
1456 uiop->uio_iovcnt = 1;
1457 uiop->uio_segflg = UIO_SYSSPACE;
1461 * clear BIO_ERROR and B_INVAL state prior to initiating the I/O. We
1462 * do this here so we do not have to do it in all the code that
1465 bp->b_flags &= ~B_INVAL;
1466 bp->b_ioflags &= ~BIO_ERROR;
1468 KASSERT(!(bp->b_flags & B_DONE), ("nfs_doio: bp %p already marked done", bp));
1470 if (bp->b_iocmd == BIO_READ) {
1471 io.iov_len = uiop->uio_resid = bp->b_bcount;
1472 io.iov_base = bp->b_data;
1473 uiop->uio_rw = UIO_READ;
1475 switch (vp->v_type) {
1477 uiop->uio_offset = ((off_t)bp->b_blkno) * DEV_BSIZE;
1478 nfsstats.read_bios++;
1479 error = (nmp->nm_rpcops->nr_readrpc)(vp, uiop, cr);
1482 if (uiop->uio_resid) {
1484 * If we had a short read with no error, we must have
1485 * hit a file hole. We should zero-fill the remainder.
1486 * This can also occur if the server hits the file EOF.
1488 * Holes used to be able to occur due to pending
1489 * writes, but that is not possible any longer.
1491 int nread = bp->b_bcount - uiop->uio_resid;
1492 int left = uiop->uio_resid;
1495 bzero((char *)bp->b_data + nread, left);
1496 uiop->uio_resid = 0;
1499 /* ASSERT_VOP_LOCKED(vp, "nfs_doio"); */
1500 if (p && (vp->v_vflag & VV_TEXT) &&
1501 (NFS_TIMESPEC_COMPARE(&np->n_mtime, &np->n_vattr.va_mtime))) {
1503 killproc(p, "text file modification");
1508 uiop->uio_offset = (off_t)0;
1509 nfsstats.readlink_bios++;
1510 error = (nmp->nm_rpcops->nr_readlinkrpc)(vp, uiop, cr);
1513 nfsstats.readdir_bios++;
1514 uiop->uio_offset = ((u_quad_t)bp->b_lblkno) * NFS_DIRBLKSIZ;
1515 if ((nmp->nm_flag & NFSMNT_NFSV4) != 0)
1516 error = nfs4_readdirrpc(vp, uiop, cr);
1518 if ((nmp->nm_flag & NFSMNT_RDIRPLUS) != 0) {
1519 error = nfs_readdirplusrpc(vp, uiop, cr);
1520 if (error == NFSERR_NOTSUPP)
1521 nmp->nm_flag &= ~NFSMNT_RDIRPLUS;
1523 if ((nmp->nm_flag & NFSMNT_RDIRPLUS) == 0)
1524 error = nfs_readdirrpc(vp, uiop, cr);
1527 * end-of-directory sets B_INVAL but does not generate an
1530 if (error == 0 && uiop->uio_resid == bp->b_bcount)
1531 bp->b_flags |= B_INVAL;
1534 printf("nfs_doio: type %x unexpected\n", vp->v_type);
1538 bp->b_ioflags |= BIO_ERROR;
1539 bp->b_error = error;
1543 * If we only need to commit, try to commit
1545 if (bp->b_flags & B_NEEDCOMMIT) {
1549 off = ((u_quad_t)bp->b_blkno) * DEV_BSIZE + bp->b_dirtyoff;
1550 retv = (nmp->nm_rpcops->nr_commit)(
1551 vp, off, bp->b_dirtyend-bp->b_dirtyoff,
1554 bp->b_dirtyoff = bp->b_dirtyend = 0;
1555 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1560 if (retv == NFSERR_STALEWRITEVERF) {
1561 nfs_clearcommit(vp->v_mount);
1566 * Setup for actual write
1569 if ((off_t)bp->b_blkno * DEV_BSIZE + bp->b_dirtyend > np->n_size)
1570 bp->b_dirtyend = np->n_size - (off_t)bp->b_blkno * DEV_BSIZE;
1572 if (bp->b_dirtyend > bp->b_dirtyoff) {
1573 io.iov_len = uiop->uio_resid = bp->b_dirtyend
1575 uiop->uio_offset = (off_t)bp->b_blkno * DEV_BSIZE
1577 io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
1578 uiop->uio_rw = UIO_WRITE;
1579 nfsstats.write_bios++;
1581 if ((bp->b_flags & (B_ASYNC | B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == B_ASYNC)
1582 iomode = NFSV3WRITE_UNSTABLE;
1584 iomode = NFSV3WRITE_FILESYNC;
1586 error = (nmp->nm_rpcops->nr_writerpc)(vp, uiop, cr, &iomode, &must_commit);
1589 * When setting B_NEEDCOMMIT also set B_CLUSTEROK to try
1590 * to cluster the buffers needing commit. This will allow
1591 * the system to submit a single commit rpc for the whole
1592 * cluster. We can do this even if the buffer is not 100%
1593 * dirty (relative to the NFS blocksize), so we optimize the
1594 * append-to-file-case.
1596 * (when clearing B_NEEDCOMMIT, B_CLUSTEROK must also be
1597 * cleared because write clustering only works for commit
1598 * rpc's, not for the data portion of the write).
1601 if (!error && iomode == NFSV3WRITE_UNSTABLE) {
1602 bp->b_flags |= B_NEEDCOMMIT;
1603 if (bp->b_dirtyoff == 0
1604 && bp->b_dirtyend == bp->b_bcount)
1605 bp->b_flags |= B_CLUSTEROK;
1607 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1611 * For an interrupted write, the buffer is still valid
1612 * and the write hasn't been pushed to the server yet,
1613 * so we can't set BIO_ERROR and report the interruption
1614 * by setting B_EINTR. For the B_ASYNC case, B_EINTR
1615 * is not relevant, so the rpc attempt is essentially
1616 * a noop. For the case of a V3 write rpc not being
1617 * committed to stable storage, the block is still
1618 * dirty and requires either a commit rpc or another
1619 * write rpc with iomode == NFSV3WRITE_FILESYNC before
1620 * the block is reused. This is indicated by setting
1621 * the B_DELWRI and B_NEEDCOMMIT flags.
1623 * If the buffer is marked B_PAGING, it does not reside on
1624 * the vp's paging queues so we cannot call bdirty(). The
1625 * bp in this case is not an NFS cache block so we should
1628 if (error == EINTR || error == EIO
1629 || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
1633 bp->b_flags &= ~(B_INVAL|B_NOCACHE);
1634 if ((bp->b_flags & B_PAGING) == 0) {
1636 bp->b_flags &= ~B_DONE;
1638 if (error && (bp->b_flags & B_ASYNC) == 0)
1639 bp->b_flags |= B_EINTR;
1643 bp->b_ioflags |= BIO_ERROR;
1644 bp->b_error = np->n_error = error;
1645 np->n_flag |= NWRITEERR;
1647 bp->b_dirtyoff = bp->b_dirtyend = 0;
1655 bp->b_resid = uiop->uio_resid;
1657 nfs_clearcommit(vp->v_mount);
1663 * Used to aid in handling ftruncate() operations on the NFS client side.
1664 * Truncation creates a number of special problems for NFS. We have to
1665 * throw away VM pages and buffer cache buffers that are beyond EOF, and
1666 * we have to properly handle VM pages or (potentially dirty) buffers
1667 * that straddle the truncation point.
1671 nfs_meta_setsize(struct vnode *vp, struct ucred *cred, struct thread *td, u_quad_t nsize)
1673 struct nfsnode *np = VTONFS(vp);
1674 u_quad_t tsize = np->n_size;
1675 int biosize = vp->v_mount->mnt_stat.f_iosize;
1680 if (np->n_size < tsize) {
1686 * vtruncbuf() doesn't get the buffer overlapping the
1687 * truncation point. We may have a B_DELWRI and/or B_CACHE
1688 * buffer that now needs to be truncated.
1690 error = vtruncbuf(vp, cred, td, nsize, biosize);
1691 lbn = nsize / biosize;
1692 bufsize = nsize & (biosize - 1);
1693 bp = nfs_getcacheblk(vp, lbn, bufsize, td);
1696 if (bp->b_dirtyoff > bp->b_bcount)
1697 bp->b_dirtyoff = bp->b_bcount;
1698 if (bp->b_dirtyend > bp->b_bcount)
1699 bp->b_dirtyend = bp->b_bcount;
1700 bp->b_flags |= B_RELBUF; /* don't leave garbage around */
1703 vnode_pager_setsize(vp, nsize);