xref: /freebsd/sys/fs/nfsclient/nfs_clbio.c (revision 4ed925457ab06e83238a5db33e89ccc94b99a713)
1 /*-
2  * Copyright (c) 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Rick Macklem at The University of Guelph.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
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.
19  *
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
30  * SUCH DAMAGE.
31  *
32  *	@(#)nfs_bio.c	8.9 (Berkeley) 3/30/95
33  */
34 
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/bio.h>
41 #include <sys/buf.h>
42 #include <sys/kernel.h>
43 #include <sys/mount.h>
44 #include <sys/proc.h>
45 #include <sys/resourcevar.h>
46 #include <sys/signalvar.h>
47 #include <sys/vmmeter.h>
48 #include <sys/vnode.h>
49 
50 #include <vm/vm.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>
56 
57 #include <fs/nfs/nfsport.h>
58 #include <fs/nfsclient/nfsmount.h>
59 #include <fs/nfsclient/nfs.h>
60 #include <fs/nfsclient/nfsnode.h>
61 
62 extern int newnfs_directio_allow_mmap;
63 extern struct nfsstats newnfsstats;
64 extern struct mtx ncl_iod_mutex;
65 extern int ncl_numasync;
66 extern enum nfsiod_state ncl_iodwant[NFS_MAXRAHEAD];
67 extern struct nfsmount *ncl_iodmount[NFS_MAXRAHEAD];
68 extern int newnfs_directio_enable;
69 
70 int ncl_pbuf_freecnt = -1;	/* start out unlimited */
71 
72 static struct buf *nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size,
73     struct thread *td);
74 static int nfs_directio_write(struct vnode *vp, struct uio *uiop,
75     struct ucred *cred, int ioflag);
76 
77 /*
78  * Vnode op for VM getpages.
79  */
80 int
81 ncl_getpages(struct vop_getpages_args *ap)
82 {
83 	int i, error, nextoff, size, toff, count, npages;
84 	struct uio uio;
85 	struct iovec iov;
86 	vm_offset_t kva;
87 	struct buf *bp;
88 	struct vnode *vp;
89 	struct thread *td;
90 	struct ucred *cred;
91 	struct nfsmount *nmp;
92 	vm_object_t object;
93 	vm_page_t *pages;
94 	struct nfsnode *np;
95 
96 	vp = ap->a_vp;
97 	np = VTONFS(vp);
98 	td = curthread;				/* XXX */
99 	cred = curthread->td_ucred;		/* XXX */
100 	nmp = VFSTONFS(vp->v_mount);
101 	pages = ap->a_m;
102 	count = ap->a_count;
103 
104 	if ((object = vp->v_object) == NULL) {
105 		ncl_printf("nfs_getpages: called with non-merged cache vnode??\n");
106 		return (VM_PAGER_ERROR);
107 	}
108 
109 	if (newnfs_directio_enable && !newnfs_directio_allow_mmap) {
110 		mtx_lock(&np->n_mtx);
111 		if ((np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
112 			mtx_unlock(&np->n_mtx);
113 			ncl_printf("nfs_getpages: called on non-cacheable vnode??\n");
114 			return (VM_PAGER_ERROR);
115 		} else
116 			mtx_unlock(&np->n_mtx);
117 	}
118 
119 	mtx_lock(&nmp->nm_mtx);
120 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
121 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
122 		mtx_unlock(&nmp->nm_mtx);
123 		/* We'll never get here for v4, because we always have fsinfo */
124 		(void)ncl_fsinfo(nmp, vp, cred, td);
125 	} else
126 		mtx_unlock(&nmp->nm_mtx);
127 
128 	npages = btoc(count);
129 
130 	/*
131 	 * If the requested page is partially valid, just return it and
132 	 * allow the pager to zero-out the blanks.  Partially valid pages
133 	 * can only occur at the file EOF.
134 	 */
135 	VM_OBJECT_LOCK(object);
136 	if (pages[ap->a_reqpage]->valid != 0) {
137 		vm_page_lock_queues();
138 		for (i = 0; i < npages; ++i) {
139 			if (i != ap->a_reqpage)
140 				vm_page_free(pages[i]);
141 		}
142 		vm_page_unlock_queues();
143 		VM_OBJECT_UNLOCK(object);
144 		return (0);
145 	}
146 	VM_OBJECT_UNLOCK(object);
147 
148 	/*
149 	 * We use only the kva address for the buffer, but this is extremely
150 	 * convienient and fast.
151 	 */
152 	bp = getpbuf(&ncl_pbuf_freecnt);
153 
154 	kva = (vm_offset_t) bp->b_data;
155 	pmap_qenter(kva, pages, npages);
156 	PCPU_INC(cnt.v_vnodein);
157 	PCPU_ADD(cnt.v_vnodepgsin, npages);
158 
159 	iov.iov_base = (caddr_t) kva;
160 	iov.iov_len = count;
161 	uio.uio_iov = &iov;
162 	uio.uio_iovcnt = 1;
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;
167 	uio.uio_td = td;
168 
169 	error = ncl_readrpc(vp, &uio, cred);
170 	pmap_qremove(kva, npages);
171 
172 	relpbuf(bp, &ncl_pbuf_freecnt);
173 
174 	if (error && (uio.uio_resid == count)) {
175 		ncl_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]);
181 		}
182 		vm_page_unlock_queues();
183 		VM_OBJECT_UNLOCK(object);
184 		return (VM_PAGER_ERROR);
185 	}
186 
187 	/*
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!
191 	 */
192 
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) {
197 		vm_page_t m;
198 		nextoff = toff + PAGE_SIZE;
199 		m = pages[i];
200 
201 		if (nextoff <= size) {
202 			/*
203 			 * Read operation filled an entire page
204 			 */
205 			m->valid = VM_PAGE_BITS_ALL;
206 			KASSERT(m->dirty == 0,
207 			    ("nfs_getpages: page %p is dirty", m));
208 		} else if (size > toff) {
209 			/*
210 			 * Read operation filled a partial page.
211 			 */
212 			m->valid = 0;
213 			vm_page_set_valid(m, 0, size - toff);
214 			KASSERT(m->dirty == 0,
215 			    ("nfs_getpages: page %p is dirty", m));
216 		} else {
217 			/*
218 			 * Read operation was short.  If no error occured
219 			 * we may have hit a zero-fill section.   We simply
220 			 * leave valid set to 0.
221 			 */
222 			;
223 		}
224 		if (i != ap->a_reqpage) {
225 			/*
226 			 * Whether or not to leave the page activated is up in
227 			 * the air, but we should put the page on a page queue
228 			 * somewhere (it already is in the object).  Result:
229 			 * It appears that emperical results show that
230 			 * deactivating pages is best.
231 			 */
232 
233 			/*
234 			 * Just in case someone was asking for this page we
235 			 * now tell them that it is ok to use.
236 			 */
237 			if (!error) {
238 				if (m->oflags & VPO_WANTED)
239 					vm_page_activate(m);
240 				else
241 					vm_page_deactivate(m);
242 				vm_page_wakeup(m);
243 			} else {
244 				vm_page_free(m);
245 			}
246 		}
247 	}
248 	vm_page_unlock_queues();
249 	VM_OBJECT_UNLOCK(object);
250 	return (0);
251 }
252 
253 /*
254  * Vnode op for VM putpages.
255  */
256 int
257 ncl_putpages(struct vop_putpages_args *ap)
258 {
259 	struct uio uio;
260 	struct iovec iov;
261 	vm_offset_t kva;
262 	struct buf *bp;
263 	int iomode, must_commit, i, error, npages, count;
264 	off_t offset;
265 	int *rtvals;
266 	struct vnode *vp;
267 	struct thread *td;
268 	struct ucred *cred;
269 	struct nfsmount *nmp;
270 	struct nfsnode *np;
271 	vm_page_t *pages;
272 
273 	vp = ap->a_vp;
274 	np = VTONFS(vp);
275 	td = curthread;				/* XXX */
276 	cred = curthread->td_ucred;		/* XXX */
277 	nmp = VFSTONFS(vp->v_mount);
278 	pages = ap->a_m;
279 	count = ap->a_count;
280 	rtvals = ap->a_rtvals;
281 	npages = btoc(count);
282 	offset = IDX_TO_OFF(pages[0]->pindex);
283 
284 	mtx_lock(&nmp->nm_mtx);
285 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
286 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
287 		mtx_unlock(&nmp->nm_mtx);
288 		(void)ncl_fsinfo(nmp, vp, cred, td);
289 	} else
290 		mtx_unlock(&nmp->nm_mtx);
291 
292 	mtx_lock(&np->n_mtx);
293 	if (newnfs_directio_enable && !newnfs_directio_allow_mmap &&
294 	    (np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
295 		mtx_unlock(&np->n_mtx);
296 		ncl_printf("ncl_putpages: called on noncache-able vnode??\n");
297 		mtx_lock(&np->n_mtx);
298 	}
299 
300 	for (i = 0; i < npages; i++)
301 		rtvals[i] = VM_PAGER_AGAIN;
302 
303 	/*
304 	 * When putting pages, do not extend file past EOF.
305 	 */
306 	if (offset + count > np->n_size) {
307 		count = np->n_size - offset;
308 		if (count < 0)
309 			count = 0;
310 	}
311 	mtx_unlock(&np->n_mtx);
312 
313 	/*
314 	 * We use only the kva address for the buffer, but this is extremely
315 	 * convienient and fast.
316 	 */
317 	bp = getpbuf(&ncl_pbuf_freecnt);
318 
319 	kva = (vm_offset_t) bp->b_data;
320 	pmap_qenter(kva, pages, npages);
321 	PCPU_INC(cnt.v_vnodeout);
322 	PCPU_ADD(cnt.v_vnodepgsout, count);
323 
324 	iov.iov_base = (caddr_t) kva;
325 	iov.iov_len = count;
326 	uio.uio_iov = &iov;
327 	uio.uio_iovcnt = 1;
328 	uio.uio_offset = offset;
329 	uio.uio_resid = count;
330 	uio.uio_segflg = UIO_SYSSPACE;
331 	uio.uio_rw = UIO_WRITE;
332 	uio.uio_td = td;
333 
334 	if ((ap->a_sync & VM_PAGER_PUT_SYNC) == 0)
335 	    iomode = NFSWRITE_UNSTABLE;
336 	else
337 	    iomode = NFSWRITE_FILESYNC;
338 
339 	error = ncl_writerpc(vp, &uio, cred, &iomode, &must_commit);
340 
341 	pmap_qremove(kva, npages);
342 	relpbuf(bp, &ncl_pbuf_freecnt);
343 
344 	if (!error) {
345 		int nwritten = round_page(count - uio.uio_resid) / PAGE_SIZE;
346 		for (i = 0; i < nwritten; i++) {
347 			rtvals[i] = VM_PAGER_OK;
348 			vm_page_undirty(pages[i]);
349 		}
350 		if (must_commit) {
351 			ncl_clearcommit(vp->v_mount);
352 		}
353 	}
354 	return rtvals[0];
355 }
356 
357 /*
358  * For nfs, cache consistency can only be maintained approximately.
359  * Although RFC1094 does not specify the criteria, the following is
360  * believed to be compatible with the reference port.
361  * For nfs:
362  * If the file's modify time on the server has changed since the
363  * last read rpc or you have written to the file,
364  * you may have lost data cache consistency with the
365  * server, so flush all of the file's data out of the cache.
366  * Then force a getattr rpc to ensure that you have up to date
367  * attributes.
368  * NB: This implies that cache data can be read when up to
369  * NFS_ATTRTIMEO seconds out of date. If you find that you need current
370  * attributes this could be forced by setting n_attrstamp to 0 before
371  * the VOP_GETATTR() call.
372  */
373 static inline int
374 nfs_bioread_check_cons(struct vnode *vp, struct thread *td, struct ucred *cred)
375 {
376 	int error = 0;
377 	struct vattr vattr;
378 	struct nfsnode *np = VTONFS(vp);
379 	int old_lock;
380 
381 	/*
382 	 * Grab the exclusive lock before checking whether the cache is
383 	 * consistent.
384 	 * XXX - We can make this cheaper later (by acquiring cheaper locks).
385 	 * But for now, this suffices.
386 	 */
387 	old_lock = ncl_upgrade_vnlock(vp);
388 	if (vp->v_iflag & VI_DOOMED) {
389 		ncl_downgrade_vnlock(vp, old_lock);
390 		return (EBADF);
391 	}
392 
393 	mtx_lock(&np->n_mtx);
394 	if (np->n_flag & NMODIFIED) {
395 		mtx_unlock(&np->n_mtx);
396 		if (vp->v_type != VREG) {
397 			if (vp->v_type != VDIR)
398 				panic("nfs: bioread, not dir");
399 			ncl_invaldir(vp);
400 			error = ncl_vinvalbuf(vp, V_SAVE, td, 1);
401 			if (error)
402 				goto out;
403 		}
404 		np->n_attrstamp = 0;
405 		error = VOP_GETATTR(vp, &vattr, cred);
406 		if (error)
407 			goto out;
408 		mtx_lock(&np->n_mtx);
409 		np->n_mtime = vattr.va_mtime;
410 		mtx_unlock(&np->n_mtx);
411 	} else {
412 		mtx_unlock(&np->n_mtx);
413 		error = VOP_GETATTR(vp, &vattr, cred);
414 		if (error)
415 			return (error);
416 		mtx_lock(&np->n_mtx);
417 		if ((np->n_flag & NSIZECHANGED)
418 		    || (NFS_TIMESPEC_COMPARE(&np->n_mtime, &vattr.va_mtime))) {
419 			mtx_unlock(&np->n_mtx);
420 			if (vp->v_type == VDIR)
421 				ncl_invaldir(vp);
422 			error = ncl_vinvalbuf(vp, V_SAVE, td, 1);
423 			if (error)
424 				goto out;
425 			mtx_lock(&np->n_mtx);
426 			np->n_mtime = vattr.va_mtime;
427 			np->n_flag &= ~NSIZECHANGED;
428 		}
429 		mtx_unlock(&np->n_mtx);
430 	}
431 out:
432 	ncl_downgrade_vnlock(vp, old_lock);
433 	return error;
434 }
435 
436 /*
437  * Vnode op for read using bio
438  */
439 int
440 ncl_bioread(struct vnode *vp, struct uio *uio, int ioflag, struct ucred *cred)
441 {
442 	struct nfsnode *np = VTONFS(vp);
443 	int biosize, i;
444 	struct buf *bp, *rabp;
445 	struct thread *td;
446 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
447 	daddr_t lbn, rabn;
448 	int bcount;
449 	int seqcount;
450 	int nra, error = 0, n = 0, on = 0;
451 
452 #ifdef DIAGNOSTIC
453 	if (uio->uio_rw != UIO_READ)
454 		panic("ncl_read mode");
455 #endif
456 	if (uio->uio_resid == 0)
457 		return (0);
458 	if (uio->uio_offset < 0)	/* XXX VDIR cookies can be negative */
459 		return (EINVAL);
460 	td = uio->uio_td;
461 
462 	mtx_lock(&nmp->nm_mtx);
463 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
464 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
465 		mtx_unlock(&nmp->nm_mtx);
466 		(void)ncl_fsinfo(nmp, vp, cred, td);
467 		mtx_lock(&nmp->nm_mtx);
468 	}
469 	if (nmp->nm_rsize == 0 || nmp->nm_readdirsize == 0)
470 		(void) newnfs_iosize(nmp);
471 	mtx_unlock(&nmp->nm_mtx);
472 
473 	if (vp->v_type != VDIR &&
474 	    (uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
475 		return (EFBIG);
476 
477 	if (newnfs_directio_enable && (ioflag & IO_DIRECT) && (vp->v_type == VREG))
478 		/* No caching/ no readaheads. Just read data into the user buffer */
479 		return ncl_readrpc(vp, uio, cred);
480 
481 	biosize = vp->v_mount->mnt_stat.f_iosize;
482 	seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
483 
484 	error = nfs_bioread_check_cons(vp, td, cred);
485 	if (error)
486 		return error;
487 
488 	do {
489 	    u_quad_t nsize;
490 
491 	    mtx_lock(&np->n_mtx);
492 	    nsize = np->n_size;
493 	    mtx_unlock(&np->n_mtx);
494 
495 	    switch (vp->v_type) {
496 	    case VREG:
497 		NFSINCRGLOBAL(newnfsstats.biocache_reads);
498 		lbn = uio->uio_offset / biosize;
499 		on = uio->uio_offset & (biosize - 1);
500 
501 		/*
502 		 * Start the read ahead(s), as required.
503 		 */
504 		if (nmp->nm_readahead > 0) {
505 		    for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
506 			(off_t)(lbn + 1 + nra) * biosize < nsize; nra++) {
507 			rabn = lbn + 1 + nra;
508 			if (incore(&vp->v_bufobj, rabn) == NULL) {
509 			    rabp = nfs_getcacheblk(vp, rabn, biosize, td);
510 			    if (!rabp) {
511 				error = newnfs_sigintr(nmp, td);
512 				if (error)
513 				    return (error);
514 				else
515 				    break;
516 			    }
517 			    if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
518 				rabp->b_flags |= B_ASYNC;
519 				rabp->b_iocmd = BIO_READ;
520 				vfs_busy_pages(rabp, 0);
521 				if (ncl_asyncio(nmp, rabp, cred, td)) {
522 				    rabp->b_flags |= B_INVAL;
523 				    rabp->b_ioflags |= BIO_ERROR;
524 				    vfs_unbusy_pages(rabp);
525 				    brelse(rabp);
526 				    break;
527 				}
528 			    } else {
529 				brelse(rabp);
530 			    }
531 			}
532 		    }
533 		}
534 
535 		/* Note that bcount is *not* DEV_BSIZE aligned. */
536 		bcount = biosize;
537 		if ((off_t)lbn * biosize >= nsize) {
538 			bcount = 0;
539 		} else if ((off_t)(lbn + 1) * biosize > nsize) {
540 			bcount = nsize - (off_t)lbn * biosize;
541 		}
542 		bp = nfs_getcacheblk(vp, lbn, bcount, td);
543 
544 		if (!bp) {
545 			error = newnfs_sigintr(nmp, td);
546 			return (error ? error : EINTR);
547 		}
548 
549 		/*
550 		 * If B_CACHE is not set, we must issue the read.  If this
551 		 * fails, we return an error.
552 		 */
553 
554 		if ((bp->b_flags & B_CACHE) == 0) {
555 		    bp->b_iocmd = BIO_READ;
556 		    vfs_busy_pages(bp, 0);
557 		    error = ncl_doio(vp, bp, cred, td);
558 		    if (error) {
559 			brelse(bp);
560 			return (error);
561 		    }
562 		}
563 
564 		/*
565 		 * on is the offset into the current bp.  Figure out how many
566 		 * bytes we can copy out of the bp.  Note that bcount is
567 		 * NOT DEV_BSIZE aligned.
568 		 *
569 		 * Then figure out how many bytes we can copy into the uio.
570 		 */
571 
572 		n = 0;
573 		if (on < bcount)
574 			n = min((unsigned)(bcount - on), uio->uio_resid);
575 		break;
576 	    case VLNK:
577 		NFSINCRGLOBAL(newnfsstats.biocache_readlinks);
578 		bp = nfs_getcacheblk(vp, (daddr_t)0, NFS_MAXPATHLEN, td);
579 		if (!bp) {
580 			error = newnfs_sigintr(nmp, td);
581 			return (error ? error : EINTR);
582 		}
583 		if ((bp->b_flags & B_CACHE) == 0) {
584 		    bp->b_iocmd = BIO_READ;
585 		    vfs_busy_pages(bp, 0);
586 		    error = ncl_doio(vp, bp, cred, td);
587 		    if (error) {
588 			bp->b_ioflags |= BIO_ERROR;
589 			brelse(bp);
590 			return (error);
591 		    }
592 		}
593 		n = min(uio->uio_resid, NFS_MAXPATHLEN - bp->b_resid);
594 		on = 0;
595 		break;
596 	    case VDIR:
597 		NFSINCRGLOBAL(newnfsstats.biocache_readdirs);
598 		if (np->n_direofoffset
599 		    && uio->uio_offset >= np->n_direofoffset) {
600 		    return (0);
601 		}
602 		lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
603 		on = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
604 		bp = nfs_getcacheblk(vp, lbn, NFS_DIRBLKSIZ, td);
605 		if (!bp) {
606 		    error = newnfs_sigintr(nmp, td);
607 		    return (error ? error : EINTR);
608 		}
609 		if ((bp->b_flags & B_CACHE) == 0) {
610 		    bp->b_iocmd = BIO_READ;
611 		    vfs_busy_pages(bp, 0);
612 		    error = ncl_doio(vp, bp, cred, td);
613 		    if (error) {
614 			    brelse(bp);
615 		    }
616 		    while (error == NFSERR_BAD_COOKIE) {
617 			ncl_invaldir(vp);
618 			error = ncl_vinvalbuf(vp, 0, td, 1);
619 			/*
620 			 * Yuck! The directory has been modified on the
621 			 * server. The only way to get the block is by
622 			 * reading from the beginning to get all the
623 			 * offset cookies.
624 			 *
625 			 * Leave the last bp intact unless there is an error.
626 			 * Loop back up to the while if the error is another
627 			 * NFSERR_BAD_COOKIE (double yuch!).
628 			 */
629 			for (i = 0; i <= lbn && !error; i++) {
630 			    if (np->n_direofoffset
631 				&& (i * NFS_DIRBLKSIZ) >= np->n_direofoffset)
632 				    return (0);
633 			    bp = nfs_getcacheblk(vp, i, NFS_DIRBLKSIZ, td);
634 			    if (!bp) {
635 				error = newnfs_sigintr(nmp, td);
636 				return (error ? error : EINTR);
637 			    }
638 			    if ((bp->b_flags & B_CACHE) == 0) {
639 				    bp->b_iocmd = BIO_READ;
640 				    vfs_busy_pages(bp, 0);
641 				    error = ncl_doio(vp, bp, cred, td);
642 				    /*
643 				     * no error + B_INVAL == directory EOF,
644 				     * use the block.
645 				     */
646 				    if (error == 0 && (bp->b_flags & B_INVAL))
647 					    break;
648 			    }
649 			    /*
650 			     * An error will throw away the block and the
651 			     * for loop will break out.  If no error and this
652 			     * is not the block we want, we throw away the
653 			     * block and go for the next one via the for loop.
654 			     */
655 			    if (error || i < lbn)
656 				    brelse(bp);
657 			}
658 		    }
659 		    /*
660 		     * The above while is repeated if we hit another cookie
661 		     * error.  If we hit an error and it wasn't a cookie error,
662 		     * we give up.
663 		     */
664 		    if (error)
665 			    return (error);
666 		}
667 
668 		/*
669 		 * If not eof and read aheads are enabled, start one.
670 		 * (You need the current block first, so that you have the
671 		 *  directory offset cookie of the next block.)
672 		 */
673 		if (nmp->nm_readahead > 0 &&
674 		    (bp->b_flags & B_INVAL) == 0 &&
675 		    (np->n_direofoffset == 0 ||
676 		    (lbn + 1) * NFS_DIRBLKSIZ < np->n_direofoffset) &&
677 		    incore(&vp->v_bufobj, lbn + 1) == NULL) {
678 			rabp = nfs_getcacheblk(vp, lbn + 1, NFS_DIRBLKSIZ, td);
679 			if (rabp) {
680 			    if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
681 				rabp->b_flags |= B_ASYNC;
682 				rabp->b_iocmd = BIO_READ;
683 				vfs_busy_pages(rabp, 0);
684 				if (ncl_asyncio(nmp, rabp, cred, td)) {
685 				    rabp->b_flags |= B_INVAL;
686 				    rabp->b_ioflags |= BIO_ERROR;
687 				    vfs_unbusy_pages(rabp);
688 				    brelse(rabp);
689 				}
690 			    } else {
691 				brelse(rabp);
692 			    }
693 			}
694 		}
695 		/*
696 		 * Unlike VREG files, whos buffer size ( bp->b_bcount ) is
697 		 * chopped for the EOF condition, we cannot tell how large
698 		 * NFS directories are going to be until we hit EOF.  So
699 		 * an NFS directory buffer is *not* chopped to its EOF.  Now,
700 		 * it just so happens that b_resid will effectively chop it
701 		 * to EOF.  *BUT* this information is lost if the buffer goes
702 		 * away and is reconstituted into a B_CACHE state ( due to
703 		 * being VMIO ) later.  So we keep track of the directory eof
704 		 * in np->n_direofoffset and chop it off as an extra step
705 		 * right here.
706 		 */
707 		n = lmin(uio->uio_resid, NFS_DIRBLKSIZ - bp->b_resid - on);
708 		if (np->n_direofoffset && n > np->n_direofoffset - uio->uio_offset)
709 			n = np->n_direofoffset - uio->uio_offset;
710 		break;
711 	    default:
712 		ncl_printf(" ncl_bioread: type %x unexpected\n", vp->v_type);
713 		bp = NULL;
714 		break;
715 	    };
716 
717 	    if (n > 0) {
718 		    error = uiomove(bp->b_data + on, (int)n, uio);
719 	    }
720 	    if (vp->v_type == VLNK)
721 		n = 0;
722 	    if (bp != NULL)
723 		brelse(bp);
724 	} while (error == 0 && uio->uio_resid > 0 && n > 0);
725 	return (error);
726 }
727 
728 /*
729  * The NFS write path cannot handle iovecs with len > 1. So we need to
730  * break up iovecs accordingly (restricting them to wsize).
731  * For the SYNC case, we can do this with 1 copy (user buffer -> mbuf).
732  * For the ASYNC case, 2 copies are needed. The first a copy from the
733  * user buffer to a staging buffer and then a second copy from the staging
734  * buffer to mbufs. This can be optimized by copying from the user buffer
735  * directly into mbufs and passing the chain down, but that requires a
736  * fair amount of re-working of the relevant codepaths (and can be done
737  * later).
738  */
739 static int
740 nfs_directio_write(vp, uiop, cred, ioflag)
741 	struct vnode *vp;
742 	struct uio *uiop;
743 	struct ucred *cred;
744 	int ioflag;
745 {
746 	int error;
747 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
748 	struct thread *td = uiop->uio_td;
749 	int size;
750 	int wsize;
751 
752 	mtx_lock(&nmp->nm_mtx);
753 	wsize = nmp->nm_wsize;
754 	mtx_unlock(&nmp->nm_mtx);
755 	if (ioflag & IO_SYNC) {
756 		int iomode, must_commit;
757 		struct uio uio;
758 		struct iovec iov;
759 do_sync:
760 		while (uiop->uio_resid > 0) {
761 			size = min(uiop->uio_resid, wsize);
762 			size = min(uiop->uio_iov->iov_len, size);
763 			iov.iov_base = uiop->uio_iov->iov_base;
764 			iov.iov_len = size;
765 			uio.uio_iov = &iov;
766 			uio.uio_iovcnt = 1;
767 			uio.uio_offset = uiop->uio_offset;
768 			uio.uio_resid = size;
769 			uio.uio_segflg = UIO_USERSPACE;
770 			uio.uio_rw = UIO_WRITE;
771 			uio.uio_td = td;
772 			iomode = NFSWRITE_FILESYNC;
773 			error = ncl_writerpc(vp, &uio, cred, &iomode,
774 			    &must_commit);
775 			KASSERT((must_commit == 0),
776 				("ncl_directio_write: Did not commit write"));
777 			if (error)
778 				return (error);
779 			uiop->uio_offset += size;
780 			uiop->uio_resid -= size;
781 			if (uiop->uio_iov->iov_len <= size) {
782 				uiop->uio_iovcnt--;
783 				uiop->uio_iov++;
784 			} else {
785 				uiop->uio_iov->iov_base =
786 					(char *)uiop->uio_iov->iov_base + size;
787 				uiop->uio_iov->iov_len -= size;
788 			}
789 		}
790 	} else {
791 		struct uio *t_uio;
792 		struct iovec *t_iov;
793 		struct buf *bp;
794 
795 		/*
796 		 * Break up the write into blocksize chunks and hand these
797 		 * over to nfsiod's for write back.
798 		 * Unfortunately, this incurs a copy of the data. Since
799 		 * the user could modify the buffer before the write is
800 		 * initiated.
801 		 *
802 		 * The obvious optimization here is that one of the 2 copies
803 		 * in the async write path can be eliminated by copying the
804 		 * data here directly into mbufs and passing the mbuf chain
805 		 * down. But that will require a fair amount of re-working
806 		 * of the code and can be done if there's enough interest
807 		 * in NFS directio access.
808 		 */
809 		while (uiop->uio_resid > 0) {
810 			size = min(uiop->uio_resid, wsize);
811 			size = min(uiop->uio_iov->iov_len, size);
812 			bp = getpbuf(&ncl_pbuf_freecnt);
813 			t_uio = malloc(sizeof(struct uio), M_NFSDIRECTIO, M_WAITOK);
814 			t_iov = malloc(sizeof(struct iovec), M_NFSDIRECTIO, M_WAITOK);
815 			t_iov->iov_base = malloc(size, M_NFSDIRECTIO, M_WAITOK);
816 			t_iov->iov_len = size;
817 			t_uio->uio_iov = t_iov;
818 			t_uio->uio_iovcnt = 1;
819 			t_uio->uio_offset = uiop->uio_offset;
820 			t_uio->uio_resid = size;
821 			t_uio->uio_segflg = UIO_SYSSPACE;
822 			t_uio->uio_rw = UIO_WRITE;
823 			t_uio->uio_td = td;
824 			bcopy(uiop->uio_iov->iov_base, t_iov->iov_base, size);
825 			bp->b_flags |= B_DIRECT;
826 			bp->b_iocmd = BIO_WRITE;
827 			if (cred != NOCRED) {
828 				crhold(cred);
829 				bp->b_wcred = cred;
830 			} else
831 				bp->b_wcred = NOCRED;
832 			bp->b_caller1 = (void *)t_uio;
833 			bp->b_vp = vp;
834 			error = ncl_asyncio(nmp, bp, NOCRED, td);
835 			if (error) {
836 				free(t_iov->iov_base, M_NFSDIRECTIO);
837 				free(t_iov, M_NFSDIRECTIO);
838 				free(t_uio, M_NFSDIRECTIO);
839 				bp->b_vp = NULL;
840 				relpbuf(bp, &ncl_pbuf_freecnt);
841 				if (error == EINTR)
842 					return (error);
843 				goto do_sync;
844 			}
845 			uiop->uio_offset += size;
846 			uiop->uio_resid -= size;
847 			if (uiop->uio_iov->iov_len <= size) {
848 				uiop->uio_iovcnt--;
849 				uiop->uio_iov++;
850 			} else {
851 				uiop->uio_iov->iov_base =
852 					(char *)uiop->uio_iov->iov_base + size;
853 				uiop->uio_iov->iov_len -= size;
854 			}
855 		}
856 	}
857 	return (0);
858 }
859 
860 /*
861  * Vnode op for write using bio
862  */
863 int
864 ncl_write(struct vop_write_args *ap)
865 {
866 	int biosize;
867 	struct uio *uio = ap->a_uio;
868 	struct thread *td = uio->uio_td;
869 	struct vnode *vp = ap->a_vp;
870 	struct nfsnode *np = VTONFS(vp);
871 	struct ucred *cred = ap->a_cred;
872 	int ioflag = ap->a_ioflag;
873 	struct buf *bp;
874 	struct vattr vattr;
875 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
876 	daddr_t lbn;
877 	int bcount;
878 	int n, on, error = 0;
879 	struct proc *p = td?td->td_proc:NULL;
880 
881 #ifdef DIAGNOSTIC
882 	if (uio->uio_rw != UIO_WRITE)
883 		panic("ncl_write mode");
884 	if (uio->uio_segflg == UIO_USERSPACE && uio->uio_td != curthread)
885 		panic("ncl_write proc");
886 #endif
887 	if (vp->v_type != VREG)
888 		return (EIO);
889 	mtx_lock(&np->n_mtx);
890 	if (np->n_flag & NWRITEERR) {
891 		np->n_flag &= ~NWRITEERR;
892 		mtx_unlock(&np->n_mtx);
893 		return (np->n_error);
894 	} else
895 		mtx_unlock(&np->n_mtx);
896 	mtx_lock(&nmp->nm_mtx);
897 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
898 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
899 		mtx_unlock(&nmp->nm_mtx);
900 		(void)ncl_fsinfo(nmp, vp, cred, td);
901 		mtx_lock(&nmp->nm_mtx);
902 	}
903 	if (nmp->nm_wsize == 0)
904 		(void) newnfs_iosize(nmp);
905 	mtx_unlock(&nmp->nm_mtx);
906 
907 	/*
908 	 * Synchronously flush pending buffers if we are in synchronous
909 	 * mode or if we are appending.
910 	 */
911 	if (ioflag & (IO_APPEND | IO_SYNC)) {
912 		mtx_lock(&np->n_mtx);
913 		if (np->n_flag & NMODIFIED) {
914 			mtx_unlock(&np->n_mtx);
915 #ifdef notyet /* Needs matching nonblock semantics elsewhere, too. */
916 			/*
917 			 * Require non-blocking, synchronous writes to
918 			 * dirty files to inform the program it needs
919 			 * to fsync(2) explicitly.
920 			 */
921 			if (ioflag & IO_NDELAY)
922 				return (EAGAIN);
923 #endif
924 flush_and_restart:
925 			np->n_attrstamp = 0;
926 			error = ncl_vinvalbuf(vp, V_SAVE, td, 1);
927 			if (error)
928 				return (error);
929 		} else
930 			mtx_unlock(&np->n_mtx);
931 	}
932 
933 	/*
934 	 * If IO_APPEND then load uio_offset.  We restart here if we cannot
935 	 * get the append lock.
936 	 */
937 	if (ioflag & IO_APPEND) {
938 		np->n_attrstamp = 0;
939 		error = VOP_GETATTR(vp, &vattr, cred);
940 		if (error)
941 			return (error);
942 		mtx_lock(&np->n_mtx);
943 		uio->uio_offset = np->n_size;
944 		mtx_unlock(&np->n_mtx);
945 	}
946 
947 	if (uio->uio_offset < 0)
948 		return (EINVAL);
949 	if ((uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
950 		return (EFBIG);
951 	if (uio->uio_resid == 0)
952 		return (0);
953 
954 	if (newnfs_directio_enable && (ioflag & IO_DIRECT) && vp->v_type == VREG)
955 		return nfs_directio_write(vp, uio, cred, ioflag);
956 
957 	/*
958 	 * Maybe this should be above the vnode op call, but so long as
959 	 * file servers have no limits, i don't think it matters
960 	 */
961 	if (p != NULL) {
962 		PROC_LOCK(p);
963 		if (uio->uio_offset + uio->uio_resid >
964 		    lim_cur(p, RLIMIT_FSIZE)) {
965 			psignal(p, SIGXFSZ);
966 			PROC_UNLOCK(p);
967 			return (EFBIG);
968 		}
969 		PROC_UNLOCK(p);
970 	}
971 
972 	biosize = vp->v_mount->mnt_stat.f_iosize;
973 	/*
974 	 * Find all of this file's B_NEEDCOMMIT buffers.  If our writes
975 	 * would exceed the local maximum per-file write commit size when
976 	 * combined with those, we must decide whether to flush,
977 	 * go synchronous, or return error.  We don't bother checking
978 	 * IO_UNIT -- we just make all writes atomic anyway, as there's
979 	 * no point optimizing for something that really won't ever happen.
980 	 */
981 	if (!(ioflag & IO_SYNC)) {
982 		int nflag;
983 
984 		mtx_lock(&np->n_mtx);
985 		nflag = np->n_flag;
986 		mtx_unlock(&np->n_mtx);
987 		int needrestart = 0;
988 		if (nmp->nm_wcommitsize < uio->uio_resid) {
989 			/*
990 			 * If this request could not possibly be completed
991 			 * without exceeding the maximum outstanding write
992 			 * commit size, see if we can convert it into a
993 			 * synchronous write operation.
994 			 */
995 			if (ioflag & IO_NDELAY)
996 				return (EAGAIN);
997 			ioflag |= IO_SYNC;
998 			if (nflag & NMODIFIED)
999 				needrestart = 1;
1000 		} else if (nflag & NMODIFIED) {
1001 			int wouldcommit = 0;
1002 			BO_LOCK(&vp->v_bufobj);
1003 			if (vp->v_bufobj.bo_dirty.bv_cnt != 0) {
1004 				TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd,
1005 				    b_bobufs) {
1006 					if (bp->b_flags & B_NEEDCOMMIT)
1007 						wouldcommit += bp->b_bcount;
1008 				}
1009 			}
1010 			BO_UNLOCK(&vp->v_bufobj);
1011 			/*
1012 			 * Since we're not operating synchronously and
1013 			 * bypassing the buffer cache, we are in a commit
1014 			 * and holding all of these buffers whether
1015 			 * transmitted or not.  If not limited, this
1016 			 * will lead to the buffer cache deadlocking,
1017 			 * as no one else can flush our uncommitted buffers.
1018 			 */
1019 			wouldcommit += uio->uio_resid;
1020 			/*
1021 			 * If we would initially exceed the maximum
1022 			 * outstanding write commit size, flush and restart.
1023 			 */
1024 			if (wouldcommit > nmp->nm_wcommitsize)
1025 				needrestart = 1;
1026 		}
1027 		if (needrestart)
1028 			goto flush_and_restart;
1029 	}
1030 
1031 	do {
1032 		NFSINCRGLOBAL(newnfsstats.biocache_writes);
1033 		lbn = uio->uio_offset / biosize;
1034 		on = uio->uio_offset & (biosize-1);
1035 		n = min((unsigned)(biosize - on), uio->uio_resid);
1036 again:
1037 		/*
1038 		 * Handle direct append and file extension cases, calculate
1039 		 * unaligned buffer size.
1040 		 */
1041 		mtx_lock(&np->n_mtx);
1042 		if (uio->uio_offset == np->n_size && n) {
1043 			mtx_unlock(&np->n_mtx);
1044 			/*
1045 			 * Get the buffer (in its pre-append state to maintain
1046 			 * B_CACHE if it was previously set).  Resize the
1047 			 * nfsnode after we have locked the buffer to prevent
1048 			 * readers from reading garbage.
1049 			 */
1050 			bcount = on;
1051 			bp = nfs_getcacheblk(vp, lbn, bcount, td);
1052 
1053 			if (bp != NULL) {
1054 				long save;
1055 
1056 				mtx_lock(&np->n_mtx);
1057 				np->n_size = uio->uio_offset + n;
1058 				np->n_flag |= NMODIFIED;
1059 				vnode_pager_setsize(vp, np->n_size);
1060 				mtx_unlock(&np->n_mtx);
1061 
1062 				save = bp->b_flags & B_CACHE;
1063 				bcount += n;
1064 				allocbuf(bp, bcount);
1065 				bp->b_flags |= save;
1066 			}
1067 		} else {
1068 			/*
1069 			 * Obtain the locked cache block first, and then
1070 			 * adjust the file's size as appropriate.
1071 			 */
1072 			bcount = on + n;
1073 			if ((off_t)lbn * biosize + bcount < np->n_size) {
1074 				if ((off_t)(lbn + 1) * biosize < np->n_size)
1075 					bcount = biosize;
1076 				else
1077 					bcount = np->n_size - (off_t)lbn * biosize;
1078 			}
1079 			mtx_unlock(&np->n_mtx);
1080 			bp = nfs_getcacheblk(vp, lbn, bcount, td);
1081 			mtx_lock(&np->n_mtx);
1082 			if (uio->uio_offset + n > np->n_size) {
1083 				np->n_size = uio->uio_offset + n;
1084 				np->n_flag |= NMODIFIED;
1085 				vnode_pager_setsize(vp, np->n_size);
1086 			}
1087 			mtx_unlock(&np->n_mtx);
1088 		}
1089 
1090 		if (!bp) {
1091 			error = newnfs_sigintr(nmp, td);
1092 			if (!error)
1093 				error = EINTR;
1094 			break;
1095 		}
1096 
1097 		/*
1098 		 * Issue a READ if B_CACHE is not set.  In special-append
1099 		 * mode, B_CACHE is based on the buffer prior to the write
1100 		 * op and is typically set, avoiding the read.  If a read
1101 		 * is required in special append mode, the server will
1102 		 * probably send us a short-read since we extended the file
1103 		 * on our end, resulting in b_resid == 0 and, thusly,
1104 		 * B_CACHE getting set.
1105 		 *
1106 		 * We can also avoid issuing the read if the write covers
1107 		 * the entire buffer.  We have to make sure the buffer state
1108 		 * is reasonable in this case since we will not be initiating
1109 		 * I/O.  See the comments in kern/vfs_bio.c's getblk() for
1110 		 * more information.
1111 		 *
1112 		 * B_CACHE may also be set due to the buffer being cached
1113 		 * normally.
1114 		 */
1115 
1116 		if (on == 0 && n == bcount) {
1117 			bp->b_flags |= B_CACHE;
1118 			bp->b_flags &= ~B_INVAL;
1119 			bp->b_ioflags &= ~BIO_ERROR;
1120 		}
1121 
1122 		if ((bp->b_flags & B_CACHE) == 0) {
1123 			bp->b_iocmd = BIO_READ;
1124 			vfs_busy_pages(bp, 0);
1125 			error = ncl_doio(vp, bp, cred, td);
1126 			if (error) {
1127 				brelse(bp);
1128 				break;
1129 			}
1130 		}
1131 		if (bp->b_wcred == NOCRED)
1132 			bp->b_wcred = crhold(cred);
1133 		mtx_lock(&np->n_mtx);
1134 		np->n_flag |= NMODIFIED;
1135 		mtx_unlock(&np->n_mtx);
1136 
1137 		/*
1138 		 * If dirtyend exceeds file size, chop it down.  This should
1139 		 * not normally occur but there is an append race where it
1140 		 * might occur XXX, so we log it.
1141 		 *
1142 		 * If the chopping creates a reverse-indexed or degenerate
1143 		 * situation with dirtyoff/end, we 0 both of them.
1144 		 */
1145 
1146 		if (bp->b_dirtyend > bcount) {
1147 			ncl_printf("NFS append race @%lx:%d\n",
1148 			    (long)bp->b_blkno * DEV_BSIZE,
1149 			    bp->b_dirtyend - bcount);
1150 			bp->b_dirtyend = bcount;
1151 		}
1152 
1153 		if (bp->b_dirtyoff >= bp->b_dirtyend)
1154 			bp->b_dirtyoff = bp->b_dirtyend = 0;
1155 
1156 		/*
1157 		 * If the new write will leave a contiguous dirty
1158 		 * area, just update the b_dirtyoff and b_dirtyend,
1159 		 * otherwise force a write rpc of the old dirty area.
1160 		 *
1161 		 * While it is possible to merge discontiguous writes due to
1162 		 * our having a B_CACHE buffer ( and thus valid read data
1163 		 * for the hole), we don't because it could lead to
1164 		 * significant cache coherency problems with multiple clients,
1165 		 * especially if locking is implemented later on.
1166 		 *
1167 		 * as an optimization we could theoretically maintain
1168 		 * a linked list of discontinuous areas, but we would still
1169 		 * have to commit them separately so there isn't much
1170 		 * advantage to it except perhaps a bit of asynchronization.
1171 		 */
1172 
1173 		if (bp->b_dirtyend > 0 &&
1174 		    (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) {
1175 			if (bwrite(bp) == EINTR) {
1176 				error = EINTR;
1177 				break;
1178 			}
1179 			goto again;
1180 		}
1181 
1182 		error = uiomove((char *)bp->b_data + on, n, uio);
1183 
1184 		/*
1185 		 * Since this block is being modified, it must be written
1186 		 * again and not just committed.  Since write clustering does
1187 		 * not work for the stage 1 data write, only the stage 2
1188 		 * commit rpc, we have to clear B_CLUSTEROK as well.
1189 		 */
1190 		bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1191 
1192 		if (error) {
1193 			bp->b_ioflags |= BIO_ERROR;
1194 			brelse(bp);
1195 			break;
1196 		}
1197 
1198 		/*
1199 		 * Only update dirtyoff/dirtyend if not a degenerate
1200 		 * condition.
1201 		 */
1202 		if (n) {
1203 			if (bp->b_dirtyend > 0) {
1204 				bp->b_dirtyoff = min(on, bp->b_dirtyoff);
1205 				bp->b_dirtyend = max((on + n), bp->b_dirtyend);
1206 			} else {
1207 				bp->b_dirtyoff = on;
1208 				bp->b_dirtyend = on + n;
1209 			}
1210 			vfs_bio_set_valid(bp, on, n);
1211 		}
1212 
1213 		/*
1214 		 * If IO_SYNC do bwrite().
1215 		 *
1216 		 * IO_INVAL appears to be unused.  The idea appears to be
1217 		 * to turn off caching in this case.  Very odd.  XXX
1218 		 */
1219 		if ((ioflag & IO_SYNC)) {
1220 			if (ioflag & IO_INVAL)
1221 				bp->b_flags |= B_NOCACHE;
1222 			error = bwrite(bp);
1223 			if (error)
1224 				break;
1225 		} else if ((n + on) == biosize) {
1226 			bp->b_flags |= B_ASYNC;
1227 			(void) ncl_writebp(bp, 0, NULL);
1228 		} else {
1229 			bdwrite(bp);
1230 		}
1231 	} while (uio->uio_resid > 0 && n > 0);
1232 
1233 	return (error);
1234 }
1235 
1236 /*
1237  * Get an nfs cache block.
1238  *
1239  * Allocate a new one if the block isn't currently in the cache
1240  * and return the block marked busy. If the calling process is
1241  * interrupted by a signal for an interruptible mount point, return
1242  * NULL.
1243  *
1244  * The caller must carefully deal with the possible B_INVAL state of
1245  * the buffer.  ncl_doio() clears B_INVAL (and ncl_asyncio() clears it
1246  * indirectly), so synchronous reads can be issued without worrying about
1247  * the B_INVAL state.  We have to be a little more careful when dealing
1248  * with writes (see comments in nfs_write()) when extending a file past
1249  * its EOF.
1250  */
1251 static struct buf *
1252 nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size, struct thread *td)
1253 {
1254 	struct buf *bp;
1255 	struct mount *mp;
1256 	struct nfsmount *nmp;
1257 
1258 	mp = vp->v_mount;
1259 	nmp = VFSTONFS(mp);
1260 
1261 	if (nmp->nm_flag & NFSMNT_INT) {
1262  		sigset_t oldset;
1263 
1264  		newnfs_set_sigmask(td, &oldset);
1265 		bp = getblk(vp, bn, size, NFS_PCATCH, 0, 0);
1266  		newnfs_restore_sigmask(td, &oldset);
1267 		while (bp == NULL) {
1268 			if (newnfs_sigintr(nmp, td))
1269 				return (NULL);
1270 			bp = getblk(vp, bn, size, 0, 2 * hz, 0);
1271 		}
1272 	} else {
1273 		bp = getblk(vp, bn, size, 0, 0, 0);
1274 	}
1275 
1276 	if (vp->v_type == VREG) {
1277 		int biosize;
1278 
1279 		biosize = mp->mnt_stat.f_iosize;
1280 		bp->b_blkno = bn * (biosize / DEV_BSIZE);
1281 	}
1282 	return (bp);
1283 }
1284 
1285 /*
1286  * Flush and invalidate all dirty buffers. If another process is already
1287  * doing the flush, just wait for completion.
1288  */
1289 int
1290 ncl_vinvalbuf(struct vnode *vp, int flags, struct thread *td, int intrflg)
1291 {
1292 	struct nfsnode *np = VTONFS(vp);
1293 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
1294 	int error = 0, slpflag, slptimeo;
1295  	int old_lock = 0;
1296 
1297 	ASSERT_VOP_LOCKED(vp, "ncl_vinvalbuf");
1298 
1299 	if ((nmp->nm_flag & NFSMNT_INT) == 0)
1300 		intrflg = 0;
1301 	if ((nmp->nm_mountp->mnt_kern_flag & MNTK_UNMOUNTF))
1302 		intrflg = 1;
1303 	if (intrflg) {
1304 		slpflag = NFS_PCATCH;
1305 		slptimeo = 2 * hz;
1306 	} else {
1307 		slpflag = 0;
1308 		slptimeo = 0;
1309 	}
1310 
1311 	old_lock = ncl_upgrade_vnlock(vp);
1312 	if (vp->v_iflag & VI_DOOMED) {
1313 		/*
1314 		 * Since vgonel() uses the generic vinvalbuf() to flush
1315 		 * dirty buffers and it does not call this function, it
1316 		 * is safe to just return OK when VI_DOOMED is set.
1317 		 */
1318 		ncl_downgrade_vnlock(vp, old_lock);
1319 		return (0);
1320 	}
1321 
1322 	/*
1323 	 * Now, flush as required.
1324 	 */
1325 	if ((flags & V_SAVE) && (vp->v_bufobj.bo_object != NULL)) {
1326 		VM_OBJECT_LOCK(vp->v_bufobj.bo_object);
1327 		vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC);
1328 		VM_OBJECT_UNLOCK(vp->v_bufobj.bo_object);
1329 		/*
1330 		 * If the page clean was interrupted, fail the invalidation.
1331 		 * Not doing so, we run the risk of losing dirty pages in the
1332 		 * vinvalbuf() call below.
1333 		 */
1334 		if (intrflg && (error = newnfs_sigintr(nmp, td)))
1335 			goto out;
1336 	}
1337 
1338 	error = vinvalbuf(vp, flags, slpflag, 0);
1339 	while (error) {
1340 		if (intrflg && (error = newnfs_sigintr(nmp, td)))
1341 			goto out;
1342 		error = vinvalbuf(vp, flags, 0, slptimeo);
1343 	}
1344 	mtx_lock(&np->n_mtx);
1345 	if (np->n_directio_asyncwr == 0)
1346 		np->n_flag &= ~NMODIFIED;
1347 	mtx_unlock(&np->n_mtx);
1348 out:
1349 	ncl_downgrade_vnlock(vp, old_lock);
1350 	return error;
1351 }
1352 
1353 /*
1354  * Initiate asynchronous I/O. Return an error if no nfsiods are available.
1355  * This is mainly to avoid queueing async I/O requests when the nfsiods
1356  * are all hung on a dead server.
1357  *
1358  * Note: ncl_asyncio() does not clear (BIO_ERROR|B_INVAL) but when the bp
1359  * is eventually dequeued by the async daemon, ncl_doio() *will*.
1360  */
1361 int
1362 ncl_asyncio(struct nfsmount *nmp, struct buf *bp, struct ucred *cred, struct thread *td)
1363 {
1364 	int iod;
1365 	int gotiod;
1366 	int slpflag = 0;
1367 	int slptimeo = 0;
1368 	int error, error2;
1369 
1370 	/*
1371 	 * Unless iothreadcnt is set > 0, don't bother with async I/O
1372 	 * threads. For LAN environments, they don't buy any significant
1373 	 * performance improvement that you can't get with large block
1374 	 * sizes.
1375 	 */
1376 	if (nmp->nm_readahead == 0)
1377 		return (EPERM);
1378 
1379 	/*
1380 	 * Commits are usually short and sweet so lets save some cpu and
1381 	 * leave the async daemons for more important rpc's (such as reads
1382 	 * and writes).
1383 	 */
1384 	mtx_lock(&ncl_iod_mutex);
1385 	if (bp->b_iocmd == BIO_WRITE && (bp->b_flags & B_NEEDCOMMIT) &&
1386 	    (nmp->nm_bufqiods > ncl_numasync / 2)) {
1387 		mtx_unlock(&ncl_iod_mutex);
1388 		return(EIO);
1389 	}
1390 again:
1391 	if (nmp->nm_flag & NFSMNT_INT)
1392 		slpflag = NFS_PCATCH;
1393 	gotiod = FALSE;
1394 
1395 	/*
1396 	 * Find a free iod to process this request.
1397 	 */
1398 	for (iod = 0; iod < ncl_numasync; iod++)
1399 		if (ncl_iodwant[iod] == NFSIOD_AVAILABLE) {
1400 			gotiod = TRUE;
1401 			break;
1402 		}
1403 
1404 	/*
1405 	 * Try to create one if none are free.
1406 	 */
1407 	if (!gotiod) {
1408 		iod = ncl_nfsiodnew(1);
1409 		if (iod != -1)
1410 			gotiod = TRUE;
1411 	}
1412 
1413 	if (gotiod) {
1414 		/*
1415 		 * Found one, so wake it up and tell it which
1416 		 * mount to process.
1417 		 */
1418 		NFS_DPF(ASYNCIO, ("ncl_asyncio: waking iod %d for mount %p\n",
1419 		    iod, nmp));
1420 		ncl_iodwant[iod] = NFSIOD_NOT_AVAILABLE;
1421 		ncl_iodmount[iod] = nmp;
1422 		nmp->nm_bufqiods++;
1423 		wakeup(&ncl_iodwant[iod]);
1424 	}
1425 
1426 	/*
1427 	 * If none are free, we may already have an iod working on this mount
1428 	 * point.  If so, it will process our request.
1429 	 */
1430 	if (!gotiod) {
1431 		if (nmp->nm_bufqiods > 0) {
1432 			NFS_DPF(ASYNCIO,
1433 				("ncl_asyncio: %d iods are already processing mount %p\n",
1434 				 nmp->nm_bufqiods, nmp));
1435 			gotiod = TRUE;
1436 		}
1437 	}
1438 
1439 	/*
1440 	 * If we have an iod which can process the request, then queue
1441 	 * the buffer.
1442 	 */
1443 	if (gotiod) {
1444 		/*
1445 		 * Ensure that the queue never grows too large.  We still want
1446 		 * to asynchronize so we block rather then return EIO.
1447 		 */
1448 		while (nmp->nm_bufqlen >= 2*ncl_numasync) {
1449 			NFS_DPF(ASYNCIO,
1450 				("ncl_asyncio: waiting for mount %p queue to drain\n", nmp));
1451 			nmp->nm_bufqwant = TRUE;
1452  			error = newnfs_msleep(td, &nmp->nm_bufq,
1453 			    &ncl_iod_mutex, slpflag | PRIBIO, "nfsaio",
1454   			   slptimeo);
1455 			if (error) {
1456 				error2 = newnfs_sigintr(nmp, td);
1457 				if (error2) {
1458 					mtx_unlock(&ncl_iod_mutex);
1459 					return (error2);
1460 				}
1461 				if (slpflag == NFS_PCATCH) {
1462 					slpflag = 0;
1463 					slptimeo = 2 * hz;
1464 				}
1465 			}
1466 			/*
1467 			 * We might have lost our iod while sleeping,
1468 			 * so check and loop if nescessary.
1469 			 */
1470 			if (nmp->nm_bufqiods == 0) {
1471 				NFS_DPF(ASYNCIO,
1472 					("ncl_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
1473 				goto again;
1474 			}
1475 		}
1476 
1477 		/* We might have lost our nfsiod */
1478 		if (nmp->nm_bufqiods == 0) {
1479 			NFS_DPF(ASYNCIO,
1480 				("ncl_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
1481 			goto again;
1482 		}
1483 
1484 		if (bp->b_iocmd == BIO_READ) {
1485 			if (bp->b_rcred == NOCRED && cred != NOCRED)
1486 				bp->b_rcred = crhold(cred);
1487 		} else {
1488 			if (bp->b_wcred == NOCRED && cred != NOCRED)
1489 				bp->b_wcred = crhold(cred);
1490 		}
1491 
1492 		if (bp->b_flags & B_REMFREE)
1493 			bremfreef(bp);
1494 		BUF_KERNPROC(bp);
1495 		TAILQ_INSERT_TAIL(&nmp->nm_bufq, bp, b_freelist);
1496 		nmp->nm_bufqlen++;
1497 		if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
1498 			mtx_lock(&(VTONFS(bp->b_vp))->n_mtx);
1499 			VTONFS(bp->b_vp)->n_flag |= NMODIFIED;
1500 			VTONFS(bp->b_vp)->n_directio_asyncwr++;
1501 			mtx_unlock(&(VTONFS(bp->b_vp))->n_mtx);
1502 		}
1503 		mtx_unlock(&ncl_iod_mutex);
1504 		return (0);
1505 	}
1506 
1507 	mtx_unlock(&ncl_iod_mutex);
1508 
1509 	/*
1510 	 * All the iods are busy on other mounts, so return EIO to
1511 	 * force the caller to process the i/o synchronously.
1512 	 */
1513 	NFS_DPF(ASYNCIO, ("ncl_asyncio: no iods available, i/o is synchronous\n"));
1514 	return (EIO);
1515 }
1516 
1517 void
1518 ncl_doio_directwrite(struct buf *bp)
1519 {
1520 	int iomode, must_commit;
1521 	struct uio *uiop = (struct uio *)bp->b_caller1;
1522 	char *iov_base = uiop->uio_iov->iov_base;
1523 
1524 	iomode = NFSWRITE_FILESYNC;
1525 	uiop->uio_td = NULL; /* NULL since we're in nfsiod */
1526 	ncl_writerpc(bp->b_vp, uiop, bp->b_wcred, &iomode, &must_commit);
1527 	KASSERT((must_commit == 0), ("ncl_doio_directwrite: Did not commit write"));
1528 	free(iov_base, M_NFSDIRECTIO);
1529 	free(uiop->uio_iov, M_NFSDIRECTIO);
1530 	free(uiop, M_NFSDIRECTIO);
1531 	if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
1532 		struct nfsnode *np = VTONFS(bp->b_vp);
1533 		mtx_lock(&np->n_mtx);
1534 		np->n_directio_asyncwr--;
1535 		if (np->n_directio_asyncwr == 0) {
1536 			np->n_flag &= ~NMODIFIED;
1537 			if ((np->n_flag & NFSYNCWAIT)) {
1538 				np->n_flag &= ~NFSYNCWAIT;
1539 				wakeup((caddr_t)&np->n_directio_asyncwr);
1540 			}
1541 		}
1542 		mtx_unlock(&np->n_mtx);
1543 	}
1544 	bp->b_vp = NULL;
1545 	relpbuf(bp, &ncl_pbuf_freecnt);
1546 }
1547 
1548 /*
1549  * Do an I/O operation to/from a cache block. This may be called
1550  * synchronously or from an nfsiod.
1551  */
1552 int
1553 ncl_doio(struct vnode *vp, struct buf *bp, struct ucred *cr, struct thread *td)
1554 {
1555 	struct uio *uiop;
1556 	struct nfsnode *np;
1557 	struct nfsmount *nmp;
1558 	int error = 0, iomode, must_commit = 0;
1559 	struct uio uio;
1560 	struct iovec io;
1561 	struct proc *p = td ? td->td_proc : NULL;
1562 	uint8_t	iocmd;
1563 
1564 	np = VTONFS(vp);
1565 	nmp = VFSTONFS(vp->v_mount);
1566 	uiop = &uio;
1567 	uiop->uio_iov = &io;
1568 	uiop->uio_iovcnt = 1;
1569 	uiop->uio_segflg = UIO_SYSSPACE;
1570 	uiop->uio_td = td;
1571 
1572 	/*
1573 	 * clear BIO_ERROR and B_INVAL state prior to initiating the I/O.  We
1574 	 * do this here so we do not have to do it in all the code that
1575 	 * calls us.
1576 	 */
1577 	bp->b_flags &= ~B_INVAL;
1578 	bp->b_ioflags &= ~BIO_ERROR;
1579 
1580 	KASSERT(!(bp->b_flags & B_DONE), ("ncl_doio: bp %p already marked done", bp));
1581 	iocmd = bp->b_iocmd;
1582 	if (iocmd == BIO_READ) {
1583 	    io.iov_len = uiop->uio_resid = bp->b_bcount;
1584 	    io.iov_base = bp->b_data;
1585 	    uiop->uio_rw = UIO_READ;
1586 
1587 	    switch (vp->v_type) {
1588 	    case VREG:
1589 		uiop->uio_offset = ((off_t)bp->b_blkno) * DEV_BSIZE;
1590 		NFSINCRGLOBAL(newnfsstats.read_bios);
1591 		error = ncl_readrpc(vp, uiop, cr);
1592 
1593 		if (!error) {
1594 		    if (uiop->uio_resid) {
1595 			/*
1596 			 * If we had a short read with no error, we must have
1597 			 * hit a file hole.  We should zero-fill the remainder.
1598 			 * This can also occur if the server hits the file EOF.
1599 			 *
1600 			 * Holes used to be able to occur due to pending
1601 			 * writes, but that is not possible any longer.
1602 			 */
1603 			int nread = bp->b_bcount - uiop->uio_resid;
1604 			int left  = uiop->uio_resid;
1605 
1606 			if (left > 0)
1607 				bzero((char *)bp->b_data + nread, left);
1608 			uiop->uio_resid = 0;
1609 		    }
1610 		}
1611 		/* ASSERT_VOP_LOCKED(vp, "ncl_doio"); */
1612 		if (p && (vp->v_vflag & VV_TEXT)) {
1613 			mtx_lock(&np->n_mtx);
1614 			if (NFS_TIMESPEC_COMPARE(&np->n_mtime, &np->n_vattr.na_mtime)) {
1615 				mtx_unlock(&np->n_mtx);
1616 				PROC_LOCK(p);
1617 				killproc(p, "text file modification");
1618 				PROC_UNLOCK(p);
1619 			} else
1620 				mtx_unlock(&np->n_mtx);
1621 		}
1622 		break;
1623 	    case VLNK:
1624 		uiop->uio_offset = (off_t)0;
1625 		NFSINCRGLOBAL(newnfsstats.readlink_bios);
1626 		error = ncl_readlinkrpc(vp, uiop, cr);
1627 		break;
1628 	    case VDIR:
1629 		NFSINCRGLOBAL(newnfsstats.readdir_bios);
1630 		uiop->uio_offset = ((u_quad_t)bp->b_lblkno) * NFS_DIRBLKSIZ;
1631 		if ((nmp->nm_flag & NFSMNT_RDIRPLUS) != 0) {
1632 			error = ncl_readdirplusrpc(vp, uiop, cr, td);
1633 			if (error == NFSERR_NOTSUPP)
1634 				nmp->nm_flag &= ~NFSMNT_RDIRPLUS;
1635 		}
1636 		if ((nmp->nm_flag & NFSMNT_RDIRPLUS) == 0)
1637 			error = ncl_readdirrpc(vp, uiop, cr, td);
1638 		/*
1639 		 * end-of-directory sets B_INVAL but does not generate an
1640 		 * error.
1641 		 */
1642 		if (error == 0 && uiop->uio_resid == bp->b_bcount)
1643 			bp->b_flags |= B_INVAL;
1644 		break;
1645 	    default:
1646 		ncl_printf("ncl_doio:  type %x unexpected\n", vp->v_type);
1647 		break;
1648 	    };
1649 	    if (error) {
1650 		bp->b_ioflags |= BIO_ERROR;
1651 		bp->b_error = error;
1652 	    }
1653 	} else {
1654 	    /*
1655 	     * If we only need to commit, try to commit
1656 	     */
1657 	    if (bp->b_flags & B_NEEDCOMMIT) {
1658 		    int retv;
1659 		    off_t off;
1660 
1661 		    off = ((u_quad_t)bp->b_blkno) * DEV_BSIZE + bp->b_dirtyoff;
1662 		    retv = ncl_commit(vp, off, bp->b_dirtyend-bp->b_dirtyoff,
1663 			bp->b_wcred, td);
1664 		    if (retv == 0) {
1665 			    bp->b_dirtyoff = bp->b_dirtyend = 0;
1666 			    bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1667 			    bp->b_resid = 0;
1668 			    bufdone(bp);
1669 			    return (0);
1670 		    }
1671 		    if (retv == NFSERR_STALEWRITEVERF) {
1672 			    ncl_clearcommit(vp->v_mount);
1673 		    }
1674 	    }
1675 
1676 	    /*
1677 	     * Setup for actual write
1678 	     */
1679 	    mtx_lock(&np->n_mtx);
1680 	    if ((off_t)bp->b_blkno * DEV_BSIZE + bp->b_dirtyend > np->n_size)
1681 		bp->b_dirtyend = np->n_size - (off_t)bp->b_blkno * DEV_BSIZE;
1682 	    mtx_unlock(&np->n_mtx);
1683 
1684 	    if (bp->b_dirtyend > bp->b_dirtyoff) {
1685 		io.iov_len = uiop->uio_resid = bp->b_dirtyend
1686 		    - bp->b_dirtyoff;
1687 		uiop->uio_offset = (off_t)bp->b_blkno * DEV_BSIZE
1688 		    + bp->b_dirtyoff;
1689 		io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
1690 		uiop->uio_rw = UIO_WRITE;
1691 		NFSINCRGLOBAL(newnfsstats.write_bios);
1692 
1693 		if ((bp->b_flags & (B_ASYNC | B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == B_ASYNC)
1694 		    iomode = NFSWRITE_UNSTABLE;
1695 		else
1696 		    iomode = NFSWRITE_FILESYNC;
1697 
1698 		error = ncl_writerpc(vp, uiop, cr, &iomode, &must_commit);
1699 
1700 		/*
1701 		 * When setting B_NEEDCOMMIT also set B_CLUSTEROK to try
1702 		 * to cluster the buffers needing commit.  This will allow
1703 		 * the system to submit a single commit rpc for the whole
1704 		 * cluster.  We can do this even if the buffer is not 100%
1705 		 * dirty (relative to the NFS blocksize), so we optimize the
1706 		 * append-to-file-case.
1707 		 *
1708 		 * (when clearing B_NEEDCOMMIT, B_CLUSTEROK must also be
1709 		 * cleared because write clustering only works for commit
1710 		 * rpc's, not for the data portion of the write).
1711 		 */
1712 
1713 		if (!error && iomode == NFSWRITE_UNSTABLE) {
1714 		    bp->b_flags |= B_NEEDCOMMIT;
1715 		    if (bp->b_dirtyoff == 0
1716 			&& bp->b_dirtyend == bp->b_bcount)
1717 			bp->b_flags |= B_CLUSTEROK;
1718 		} else {
1719 		    bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1720 		}
1721 
1722 		/*
1723 		 * For an interrupted write, the buffer is still valid
1724 		 * and the write hasn't been pushed to the server yet,
1725 		 * so we can't set BIO_ERROR and report the interruption
1726 		 * by setting B_EINTR. For the B_ASYNC case, B_EINTR
1727 		 * is not relevant, so the rpc attempt is essentially
1728 		 * a noop.  For the case of a V3 write rpc not being
1729 		 * committed to stable storage, the block is still
1730 		 * dirty and requires either a commit rpc or another
1731 		 * write rpc with iomode == NFSV3WRITE_FILESYNC before
1732 		 * the block is reused. This is indicated by setting
1733 		 * the B_DELWRI and B_NEEDCOMMIT flags.
1734 		 *
1735 		 * If the buffer is marked B_PAGING, it does not reside on
1736 		 * the vp's paging queues so we cannot call bdirty().  The
1737 		 * bp in this case is not an NFS cache block so we should
1738 		 * be safe. XXX
1739 		 *
1740 		 * The logic below breaks up errors into recoverable and
1741 		 * unrecoverable. For the former, we clear B_INVAL|B_NOCACHE
1742 		 * and keep the buffer around for potential write retries.
1743 		 * For the latter (eg ESTALE), we toss the buffer away (B_INVAL)
1744 		 * and save the error in the nfsnode. This is less than ideal
1745 		 * but necessary. Keeping such buffers around could potentially
1746 		 * cause buffer exhaustion eventually (they can never be written
1747 		 * out, so will get constantly be re-dirtied). It also causes
1748 		 * all sorts of vfs panics. For non-recoverable write errors,
1749 		 * also invalidate the attrcache, so we'll be forced to go over
1750 		 * the wire for this object, returning an error to user on next
1751 		 * call (most of the time).
1752 		 */
1753     		if (error == EINTR || error == EIO || error == ETIMEDOUT
1754 		    || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
1755 			int s;
1756 
1757 			s = splbio();
1758 			bp->b_flags &= ~(B_INVAL|B_NOCACHE);
1759 			if ((bp->b_flags & B_PAGING) == 0) {
1760 			    bdirty(bp);
1761 			    bp->b_flags &= ~B_DONE;
1762 			}
1763 			if (error && (bp->b_flags & B_ASYNC) == 0)
1764 			    bp->b_flags |= B_EINTR;
1765 			splx(s);
1766 	    	} else {
1767 		    if (error) {
1768 			bp->b_ioflags |= BIO_ERROR;
1769 			bp->b_flags |= B_INVAL;
1770 			bp->b_error = np->n_error = error;
1771 			mtx_lock(&np->n_mtx);
1772 			np->n_flag |= NWRITEERR;
1773 			np->n_attrstamp = 0;
1774 			mtx_unlock(&np->n_mtx);
1775 		    }
1776 		    bp->b_dirtyoff = bp->b_dirtyend = 0;
1777 		}
1778 	    } else {
1779 		bp->b_resid = 0;
1780 		bufdone(bp);
1781 		return (0);
1782 	    }
1783 	}
1784 	bp->b_resid = uiop->uio_resid;
1785 	if (must_commit)
1786 	    ncl_clearcommit(vp->v_mount);
1787 	bufdone(bp);
1788 	return (error);
1789 }
1790 
1791 /*
1792  * Used to aid in handling ftruncate() operations on the NFS client side.
1793  * Truncation creates a number of special problems for NFS.  We have to
1794  * throw away VM pages and buffer cache buffers that are beyond EOF, and
1795  * we have to properly handle VM pages or (potentially dirty) buffers
1796  * that straddle the truncation point.
1797  */
1798 
1799 int
1800 ncl_meta_setsize(struct vnode *vp, struct ucred *cred, struct thread *td, u_quad_t nsize)
1801 {
1802 	struct nfsnode *np = VTONFS(vp);
1803 	u_quad_t tsize;
1804 	int biosize = vp->v_mount->mnt_stat.f_iosize;
1805 	int error = 0;
1806 
1807 	mtx_lock(&np->n_mtx);
1808 	tsize = np->n_size;
1809 	np->n_size = nsize;
1810 	mtx_unlock(&np->n_mtx);
1811 
1812 	if (nsize < tsize) {
1813 		struct buf *bp;
1814 		daddr_t lbn;
1815 		int bufsize;
1816 
1817 		/*
1818 		 * vtruncbuf() doesn't get the buffer overlapping the
1819 		 * truncation point.  We may have a B_DELWRI and/or B_CACHE
1820 		 * buffer that now needs to be truncated.
1821 		 */
1822 		error = vtruncbuf(vp, cred, td, nsize, biosize);
1823 		lbn = nsize / biosize;
1824 		bufsize = nsize & (biosize - 1);
1825 		bp = nfs_getcacheblk(vp, lbn, bufsize, td);
1826  		if (!bp)
1827  			return EINTR;
1828 		if (bp->b_dirtyoff > bp->b_bcount)
1829 			bp->b_dirtyoff = bp->b_bcount;
1830 		if (bp->b_dirtyend > bp->b_bcount)
1831 			bp->b_dirtyend = bp->b_bcount;
1832 		bp->b_flags |= B_RELBUF;  /* don't leave garbage around */
1833 		brelse(bp);
1834 	} else {
1835 		vnode_pager_setsize(vp, nsize);
1836 	}
1837 	return(error);
1838 }
1839 
1840