xref: /freebsd/sys/fs/nfsclient/nfs_clbio.c (revision b7c60aadbbd5c846a250c05791fe7406d6d78bf4)
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 "opt_kdtrace.h"
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/bio.h>
43 #include <sys/buf.h>
44 #include <sys/kernel.h>
45 #include <sys/mount.h>
46 #include <sys/vmmeter.h>
47 #include <sys/vnode.h>
48 
49 #include <vm/vm.h>
50 #include <vm/vm_extern.h>
51 #include <vm/vm_page.h>
52 #include <vm/vm_object.h>
53 #include <vm/vm_pager.h>
54 #include <vm/vnode_pager.h>
55 
56 #include <fs/nfs/nfsport.h>
57 #include <fs/nfsclient/nfsmount.h>
58 #include <fs/nfsclient/nfs.h>
59 #include <fs/nfsclient/nfsnode.h>
60 #include <fs/nfsclient/nfs_kdtrace.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_MAXASYNCDAEMON];
67 extern struct nfsmount *ncl_iodmount[NFS_MAXASYNCDAEMON];
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 		for (i = 0; i < npages; ++i) {
138 			if (i != ap->a_reqpage) {
139 				vm_page_lock(pages[i]);
140 				vm_page_free(pages[i]);
141 				vm_page_unlock(pages[i]);
142 			}
143 		}
144 		VM_OBJECT_UNLOCK(object);
145 		return (0);
146 	}
147 	VM_OBJECT_UNLOCK(object);
148 
149 	/*
150 	 * We use only the kva address for the buffer, but this is extremely
151 	 * convienient and fast.
152 	 */
153 	bp = getpbuf(&ncl_pbuf_freecnt);
154 
155 	kva = (vm_offset_t) bp->b_data;
156 	pmap_qenter(kva, pages, npages);
157 	PCPU_INC(cnt.v_vnodein);
158 	PCPU_ADD(cnt.v_vnodepgsin, npages);
159 
160 	iov.iov_base = (caddr_t) kva;
161 	iov.iov_len = count;
162 	uio.uio_iov = &iov;
163 	uio.uio_iovcnt = 1;
164 	uio.uio_offset = IDX_TO_OFF(pages[0]->pindex);
165 	uio.uio_resid = count;
166 	uio.uio_segflg = UIO_SYSSPACE;
167 	uio.uio_rw = UIO_READ;
168 	uio.uio_td = td;
169 
170 	error = ncl_readrpc(vp, &uio, cred);
171 	pmap_qremove(kva, npages);
172 
173 	relpbuf(bp, &ncl_pbuf_freecnt);
174 
175 	if (error && (uio.uio_resid == count)) {
176 		ncl_printf("nfs_getpages: error %d\n", error);
177 		VM_OBJECT_LOCK(object);
178 		for (i = 0; i < npages; ++i) {
179 			if (i != ap->a_reqpage) {
180 				vm_page_lock(pages[i]);
181 				vm_page_free(pages[i]);
182 				vm_page_unlock(pages[i]);
183 			}
184 		}
185 		VM_OBJECT_UNLOCK(object);
186 		return (VM_PAGER_ERROR);
187 	}
188 
189 	/*
190 	 * Calculate the number of bytes read and validate only that number
191 	 * of bytes.  Note that due to pending writes, size may be 0.  This
192 	 * does not mean that the remaining data is invalid!
193 	 */
194 
195 	size = count - uio.uio_resid;
196 	VM_OBJECT_LOCK(object);
197 	for (i = 0, toff = 0; i < npages; i++, toff = nextoff) {
198 		vm_page_t m;
199 		nextoff = toff + PAGE_SIZE;
200 		m = pages[i];
201 
202 		if (nextoff <= size) {
203 			/*
204 			 * Read operation filled an entire page
205 			 */
206 			m->valid = VM_PAGE_BITS_ALL;
207 			KASSERT(m->dirty == 0,
208 			    ("nfs_getpages: page %p is dirty", m));
209 		} else if (size > toff) {
210 			/*
211 			 * Read operation filled a partial page.
212 			 */
213 			m->valid = 0;
214 			vm_page_set_valid_range(m, 0, size - toff);
215 			KASSERT(m->dirty == 0,
216 			    ("nfs_getpages: page %p is dirty", m));
217 		} else {
218 			/*
219 			 * Read operation was short.  If no error occured
220 			 * we may have hit a zero-fill section.   We simply
221 			 * leave valid set to 0.
222 			 */
223 			;
224 		}
225 		if (i != ap->a_reqpage) {
226 			/*
227 			 * Whether or not to leave the page activated is up in
228 			 * the air, but we should put the page on a page queue
229 			 * somewhere (it already is in the object).  Result:
230 			 * It appears that emperical results show that
231 			 * deactivating pages is best.
232 			 */
233 
234 			/*
235 			 * Just in case someone was asking for this page we
236 			 * now tell them that it is ok to use.
237 			 */
238 			if (!error) {
239 				if (m->oflags & VPO_WANTED) {
240 					vm_page_lock(m);
241 					vm_page_activate(m);
242 					vm_page_unlock(m);
243 				} else {
244 					vm_page_lock(m);
245 					vm_page_deactivate(m);
246 					vm_page_unlock(m);
247 				}
248 				vm_page_wakeup(m);
249 			} else {
250 				vm_page_lock(m);
251 				vm_page_free(m);
252 				vm_page_unlock(m);
253 			}
254 		}
255 	}
256 	VM_OBJECT_UNLOCK(object);
257 	return (0);
258 }
259 
260 /*
261  * Vnode op for VM putpages.
262  */
263 int
264 ncl_putpages(struct vop_putpages_args *ap)
265 {
266 	struct uio uio;
267 	struct iovec iov;
268 	vm_offset_t kva;
269 	struct buf *bp;
270 	int iomode, must_commit, i, error, npages, count;
271 	off_t offset;
272 	int *rtvals;
273 	struct vnode *vp;
274 	struct thread *td;
275 	struct ucred *cred;
276 	struct nfsmount *nmp;
277 	struct nfsnode *np;
278 	vm_page_t *pages;
279 
280 	vp = ap->a_vp;
281 	np = VTONFS(vp);
282 	td = curthread;				/* XXX */
283 	cred = curthread->td_ucred;		/* XXX */
284 	nmp = VFSTONFS(vp->v_mount);
285 	pages = ap->a_m;
286 	count = ap->a_count;
287 	rtvals = ap->a_rtvals;
288 	npages = btoc(count);
289 	offset = IDX_TO_OFF(pages[0]->pindex);
290 
291 	mtx_lock(&nmp->nm_mtx);
292 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
293 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
294 		mtx_unlock(&nmp->nm_mtx);
295 		(void)ncl_fsinfo(nmp, vp, cred, td);
296 	} else
297 		mtx_unlock(&nmp->nm_mtx);
298 
299 	mtx_lock(&np->n_mtx);
300 	if (newnfs_directio_enable && !newnfs_directio_allow_mmap &&
301 	    (np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
302 		mtx_unlock(&np->n_mtx);
303 		ncl_printf("ncl_putpages: called on noncache-able vnode??\n");
304 		mtx_lock(&np->n_mtx);
305 	}
306 
307 	for (i = 0; i < npages; i++)
308 		rtvals[i] = VM_PAGER_ERROR;
309 
310 	/*
311 	 * When putting pages, do not extend file past EOF.
312 	 */
313 	if (offset + count > np->n_size) {
314 		count = np->n_size - offset;
315 		if (count < 0)
316 			count = 0;
317 	}
318 	mtx_unlock(&np->n_mtx);
319 
320 	/*
321 	 * We use only the kva address for the buffer, but this is extremely
322 	 * convienient and fast.
323 	 */
324 	bp = getpbuf(&ncl_pbuf_freecnt);
325 
326 	kva = (vm_offset_t) bp->b_data;
327 	pmap_qenter(kva, pages, npages);
328 	PCPU_INC(cnt.v_vnodeout);
329 	PCPU_ADD(cnt.v_vnodepgsout, count);
330 
331 	iov.iov_base = (caddr_t) kva;
332 	iov.iov_len = count;
333 	uio.uio_iov = &iov;
334 	uio.uio_iovcnt = 1;
335 	uio.uio_offset = offset;
336 	uio.uio_resid = count;
337 	uio.uio_segflg = UIO_SYSSPACE;
338 	uio.uio_rw = UIO_WRITE;
339 	uio.uio_td = td;
340 
341 	if ((ap->a_sync & VM_PAGER_PUT_SYNC) == 0)
342 	    iomode = NFSWRITE_UNSTABLE;
343 	else
344 	    iomode = NFSWRITE_FILESYNC;
345 
346 	error = ncl_writerpc(vp, &uio, cred, &iomode, &must_commit, 0);
347 
348 	pmap_qremove(kva, npages);
349 	relpbuf(bp, &ncl_pbuf_freecnt);
350 
351 	vnode_pager_undirty_pages(pages, rtvals, count - uio.uio_resid);
352 	if (must_commit)
353 		ncl_clearcommit(vp->v_mount);
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 		KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
406 		error = VOP_GETATTR(vp, &vattr, cred);
407 		if (error)
408 			goto out;
409 		mtx_lock(&np->n_mtx);
410 		np->n_mtime = vattr.va_mtime;
411 		mtx_unlock(&np->n_mtx);
412 	} else {
413 		mtx_unlock(&np->n_mtx);
414 		error = VOP_GETATTR(vp, &vattr, cred);
415 		if (error)
416 			return (error);
417 		mtx_lock(&np->n_mtx);
418 		if ((np->n_flag & NSIZECHANGED)
419 		    || (NFS_TIMESPEC_COMPARE(&np->n_mtime, &vattr.va_mtime))) {
420 			mtx_unlock(&np->n_mtx);
421 			if (vp->v_type == VDIR)
422 				ncl_invaldir(vp);
423 			error = ncl_vinvalbuf(vp, V_SAVE, td, 1);
424 			if (error)
425 				goto out;
426 			mtx_lock(&np->n_mtx);
427 			np->n_mtime = vattr.va_mtime;
428 			np->n_flag &= ~NSIZECHANGED;
429 		}
430 		mtx_unlock(&np->n_mtx);
431 	}
432 out:
433 	ncl_downgrade_vnlock(vp, old_lock);
434 	return error;
435 }
436 
437 /*
438  * Vnode op for read using bio
439  */
440 int
441 ncl_bioread(struct vnode *vp, struct uio *uio, int ioflag, struct ucred *cred)
442 {
443 	struct nfsnode *np = VTONFS(vp);
444 	int biosize, i;
445 	struct buf *bp, *rabp;
446 	struct thread *td;
447 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
448 	daddr_t lbn, rabn;
449 	int bcount;
450 	int seqcount;
451 	int nra, error = 0, n = 0, on = 0;
452 	off_t tmp_off;
453 
454 	KASSERT(uio->uio_rw == UIO_READ, ("ncl_read mode"));
455 	if (uio->uio_resid == 0)
456 		return (0);
457 	if (uio->uio_offset < 0)	/* XXX VDIR cookies can be negative */
458 		return (EINVAL);
459 	td = uio->uio_td;
460 
461 	mtx_lock(&nmp->nm_mtx);
462 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
463 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
464 		mtx_unlock(&nmp->nm_mtx);
465 		(void)ncl_fsinfo(nmp, vp, cred, td);
466 		mtx_lock(&nmp->nm_mtx);
467 	}
468 	if (nmp->nm_rsize == 0 || nmp->nm_readdirsize == 0)
469 		(void) newnfs_iosize(nmp);
470 
471 	tmp_off = uio->uio_offset + uio->uio_resid;
472 	if (vp->v_type != VDIR &&
473 	    (tmp_off > nmp->nm_maxfilesize || tmp_off < uio->uio_offset)) {
474 		mtx_unlock(&nmp->nm_mtx);
475 		return (EFBIG);
476 	}
477 	mtx_unlock(&nmp->nm_mtx);
478 
479 	if (newnfs_directio_enable && (ioflag & IO_DIRECT) && (vp->v_type == VREG))
480 		/* No caching/ no readaheads. Just read data into the user buffer */
481 		return ncl_readrpc(vp, uio, cred);
482 
483 	biosize = vp->v_bufobj.bo_bsize;
484 	seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
485 
486 	error = nfs_bioread_check_cons(vp, td, cred);
487 	if (error)
488 		return error;
489 
490 	do {
491 	    u_quad_t nsize;
492 
493 	    mtx_lock(&np->n_mtx);
494 	    nsize = np->n_size;
495 	    mtx_unlock(&np->n_mtx);
496 
497 	    switch (vp->v_type) {
498 	    case VREG:
499 		NFSINCRGLOBAL(newnfsstats.biocache_reads);
500 		lbn = uio->uio_offset / biosize;
501 		on = uio->uio_offset & (biosize - 1);
502 
503 		/*
504 		 * Start the read ahead(s), as required.
505 		 */
506 		if (nmp->nm_readahead > 0) {
507 		    for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
508 			(off_t)(lbn + 1 + nra) * biosize < nsize; nra++) {
509 			rabn = lbn + 1 + nra;
510 			if (incore(&vp->v_bufobj, rabn) == NULL) {
511 			    rabp = nfs_getcacheblk(vp, rabn, biosize, td);
512 			    if (!rabp) {
513 				error = newnfs_sigintr(nmp, td);
514 				return (error ? error : EINTR);
515 			    }
516 			    if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
517 				rabp->b_flags |= B_ASYNC;
518 				rabp->b_iocmd = BIO_READ;
519 				vfs_busy_pages(rabp, 0);
520 				if (ncl_asyncio(nmp, rabp, cred, td)) {
521 				    rabp->b_flags |= B_INVAL;
522 				    rabp->b_ioflags |= BIO_ERROR;
523 				    vfs_unbusy_pages(rabp);
524 				    brelse(rabp);
525 				    break;
526 				}
527 			    } else {
528 				brelse(rabp);
529 			    }
530 			}
531 		    }
532 		}
533 
534 		/* Note that bcount is *not* DEV_BSIZE aligned. */
535 		bcount = biosize;
536 		if ((off_t)lbn * biosize >= nsize) {
537 			bcount = 0;
538 		} else if ((off_t)(lbn + 1) * biosize > nsize) {
539 			bcount = nsize - (off_t)lbn * biosize;
540 		}
541 		bp = nfs_getcacheblk(vp, lbn, bcount, td);
542 
543 		if (!bp) {
544 			error = newnfs_sigintr(nmp, td);
545 			return (error ? error : EINTR);
546 		}
547 
548 		/*
549 		 * If B_CACHE is not set, we must issue the read.  If this
550 		 * fails, we return an error.
551 		 */
552 
553 		if ((bp->b_flags & B_CACHE) == 0) {
554 		    bp->b_iocmd = BIO_READ;
555 		    vfs_busy_pages(bp, 0);
556 		    error = ncl_doio(vp, bp, cred, td, 0);
557 		    if (error) {
558 			brelse(bp);
559 			return (error);
560 		    }
561 		}
562 
563 		/*
564 		 * on is the offset into the current bp.  Figure out how many
565 		 * bytes we can copy out of the bp.  Note that bcount is
566 		 * NOT DEV_BSIZE aligned.
567 		 *
568 		 * Then figure out how many bytes we can copy into the uio.
569 		 */
570 
571 		n = 0;
572 		if (on < bcount)
573 			n = min((unsigned)(bcount - on), uio->uio_resid);
574 		break;
575 	    case VLNK:
576 		NFSINCRGLOBAL(newnfsstats.biocache_readlinks);
577 		bp = nfs_getcacheblk(vp, (daddr_t)0, NFS_MAXPATHLEN, td);
578 		if (!bp) {
579 			error = newnfs_sigintr(nmp, td);
580 			return (error ? error : EINTR);
581 		}
582 		if ((bp->b_flags & B_CACHE) == 0) {
583 		    bp->b_iocmd = BIO_READ;
584 		    vfs_busy_pages(bp, 0);
585 		    error = ncl_doio(vp, bp, cred, td, 0);
586 		    if (error) {
587 			bp->b_ioflags |= BIO_ERROR;
588 			brelse(bp);
589 			return (error);
590 		    }
591 		}
592 		n = min(uio->uio_resid, NFS_MAXPATHLEN - bp->b_resid);
593 		on = 0;
594 		break;
595 	    case VDIR:
596 		NFSINCRGLOBAL(newnfsstats.biocache_readdirs);
597 		if (np->n_direofoffset
598 		    && uio->uio_offset >= np->n_direofoffset) {
599 		    return (0);
600 		}
601 		lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
602 		on = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
603 		bp = nfs_getcacheblk(vp, lbn, NFS_DIRBLKSIZ, td);
604 		if (!bp) {
605 		    error = newnfs_sigintr(nmp, td);
606 		    return (error ? error : EINTR);
607 		}
608 		if ((bp->b_flags & B_CACHE) == 0) {
609 		    bp->b_iocmd = BIO_READ;
610 		    vfs_busy_pages(bp, 0);
611 		    error = ncl_doio(vp, bp, cred, td, 0);
612 		    if (error) {
613 			    brelse(bp);
614 		    }
615 		    while (error == NFSERR_BAD_COOKIE) {
616 			ncl_invaldir(vp);
617 			error = ncl_vinvalbuf(vp, 0, td, 1);
618 			/*
619 			 * Yuck! The directory has been modified on the
620 			 * server. The only way to get the block is by
621 			 * reading from the beginning to get all the
622 			 * offset cookies.
623 			 *
624 			 * Leave the last bp intact unless there is an error.
625 			 * Loop back up to the while if the error is another
626 			 * NFSERR_BAD_COOKIE (double yuch!).
627 			 */
628 			for (i = 0; i <= lbn && !error; i++) {
629 			    if (np->n_direofoffset
630 				&& (i * NFS_DIRBLKSIZ) >= np->n_direofoffset)
631 				    return (0);
632 			    bp = nfs_getcacheblk(vp, i, NFS_DIRBLKSIZ, td);
633 			    if (!bp) {
634 				error = newnfs_sigintr(nmp, td);
635 				return (error ? error : EINTR);
636 			    }
637 			    if ((bp->b_flags & B_CACHE) == 0) {
638 				    bp->b_iocmd = BIO_READ;
639 				    vfs_busy_pages(bp, 0);
640 				    error = ncl_doio(vp, bp, cred, td, 0);
641 				    /*
642 				     * no error + B_INVAL == directory EOF,
643 				     * use the block.
644 				     */
645 				    if (error == 0 && (bp->b_flags & B_INVAL))
646 					    break;
647 			    }
648 			    /*
649 			     * An error will throw away the block and the
650 			     * for loop will break out.  If no error and this
651 			     * is not the block we want, we throw away the
652 			     * block and go for the next one via the for loop.
653 			     */
654 			    if (error || i < lbn)
655 				    brelse(bp);
656 			}
657 		    }
658 		    /*
659 		     * The above while is repeated if we hit another cookie
660 		     * error.  If we hit an error and it wasn't a cookie error,
661 		     * we give up.
662 		     */
663 		    if (error)
664 			    return (error);
665 		}
666 
667 		/*
668 		 * If not eof and read aheads are enabled, start one.
669 		 * (You need the current block first, so that you have the
670 		 *  directory offset cookie of the next block.)
671 		 */
672 		if (nmp->nm_readahead > 0 &&
673 		    (bp->b_flags & B_INVAL) == 0 &&
674 		    (np->n_direofoffset == 0 ||
675 		    (lbn + 1) * NFS_DIRBLKSIZ < np->n_direofoffset) &&
676 		    incore(&vp->v_bufobj, lbn + 1) == NULL) {
677 			rabp = nfs_getcacheblk(vp, lbn + 1, NFS_DIRBLKSIZ, td);
678 			if (rabp) {
679 			    if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
680 				rabp->b_flags |= B_ASYNC;
681 				rabp->b_iocmd = BIO_READ;
682 				vfs_busy_pages(rabp, 0);
683 				if (ncl_asyncio(nmp, rabp, cred, td)) {
684 				    rabp->b_flags |= B_INVAL;
685 				    rabp->b_ioflags |= BIO_ERROR;
686 				    vfs_unbusy_pages(rabp);
687 				    brelse(rabp);
688 				}
689 			    } else {
690 				brelse(rabp);
691 			    }
692 			}
693 		}
694 		/*
695 		 * Unlike VREG files, whos buffer size ( bp->b_bcount ) is
696 		 * chopped for the EOF condition, we cannot tell how large
697 		 * NFS directories are going to be until we hit EOF.  So
698 		 * an NFS directory buffer is *not* chopped to its EOF.  Now,
699 		 * it just so happens that b_resid will effectively chop it
700 		 * to EOF.  *BUT* this information is lost if the buffer goes
701 		 * away and is reconstituted into a B_CACHE state ( due to
702 		 * being VMIO ) later.  So we keep track of the directory eof
703 		 * in np->n_direofoffset and chop it off as an extra step
704 		 * right here.
705 		 */
706 		n = lmin(uio->uio_resid, NFS_DIRBLKSIZ - bp->b_resid - on);
707 		if (np->n_direofoffset && n > np->n_direofoffset - uio->uio_offset)
708 			n = np->n_direofoffset - uio->uio_offset;
709 		break;
710 	    default:
711 		ncl_printf(" ncl_bioread: type %x unexpected\n", vp->v_type);
712 		bp = NULL;
713 		break;
714 	    };
715 
716 	    if (n > 0) {
717 		    error = uiomove(bp->b_data + on, (int)n, uio);
718 	    }
719 	    if (vp->v_type == VLNK)
720 		n = 0;
721 	    if (bp != NULL)
722 		brelse(bp);
723 	} while (error == 0 && uio->uio_resid > 0 && n > 0);
724 	return (error);
725 }
726 
727 /*
728  * The NFS write path cannot handle iovecs with len > 1. So we need to
729  * break up iovecs accordingly (restricting them to wsize).
730  * For the SYNC case, we can do this with 1 copy (user buffer -> mbuf).
731  * For the ASYNC case, 2 copies are needed. The first a copy from the
732  * user buffer to a staging buffer and then a second copy from the staging
733  * buffer to mbufs. This can be optimized by copying from the user buffer
734  * directly into mbufs and passing the chain down, but that requires a
735  * fair amount of re-working of the relevant codepaths (and can be done
736  * later).
737  */
738 static int
739 nfs_directio_write(vp, uiop, cred, ioflag)
740 	struct vnode *vp;
741 	struct uio *uiop;
742 	struct ucred *cred;
743 	int ioflag;
744 {
745 	int error;
746 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
747 	struct thread *td = uiop->uio_td;
748 	int size;
749 	int wsize;
750 
751 	mtx_lock(&nmp->nm_mtx);
752 	wsize = nmp->nm_wsize;
753 	mtx_unlock(&nmp->nm_mtx);
754 	if (ioflag & IO_SYNC) {
755 		int iomode, must_commit;
756 		struct uio uio;
757 		struct iovec iov;
758 do_sync:
759 		while (uiop->uio_resid > 0) {
760 			size = min(uiop->uio_resid, wsize);
761 			size = min(uiop->uio_iov->iov_len, size);
762 			iov.iov_base = uiop->uio_iov->iov_base;
763 			iov.iov_len = size;
764 			uio.uio_iov = &iov;
765 			uio.uio_iovcnt = 1;
766 			uio.uio_offset = uiop->uio_offset;
767 			uio.uio_resid = size;
768 			uio.uio_segflg = UIO_USERSPACE;
769 			uio.uio_rw = UIO_WRITE;
770 			uio.uio_td = td;
771 			iomode = NFSWRITE_FILESYNC;
772 			error = ncl_writerpc(vp, &uio, cred, &iomode,
773 			    &must_commit, 0);
774 			KASSERT((must_commit == 0),
775 				("ncl_directio_write: Did not commit write"));
776 			if (error)
777 				return (error);
778 			uiop->uio_offset += size;
779 			uiop->uio_resid -= size;
780 			if (uiop->uio_iov->iov_len <= size) {
781 				uiop->uio_iovcnt--;
782 				uiop->uio_iov++;
783 			} else {
784 				uiop->uio_iov->iov_base =
785 					(char *)uiop->uio_iov->iov_base + size;
786 				uiop->uio_iov->iov_len -= size;
787 			}
788 		}
789 	} else {
790 		struct uio *t_uio;
791 		struct iovec *t_iov;
792 		struct buf *bp;
793 
794 		/*
795 		 * Break up the write into blocksize chunks and hand these
796 		 * over to nfsiod's for write back.
797 		 * Unfortunately, this incurs a copy of the data. Since
798 		 * the user could modify the buffer before the write is
799 		 * initiated.
800 		 *
801 		 * The obvious optimization here is that one of the 2 copies
802 		 * in the async write path can be eliminated by copying the
803 		 * data here directly into mbufs and passing the mbuf chain
804 		 * down. But that will require a fair amount of re-working
805 		 * of the code and can be done if there's enough interest
806 		 * in NFS directio access.
807 		 */
808 		while (uiop->uio_resid > 0) {
809 			size = min(uiop->uio_resid, wsize);
810 			size = min(uiop->uio_iov->iov_len, size);
811 			bp = getpbuf(&ncl_pbuf_freecnt);
812 			t_uio = malloc(sizeof(struct uio), M_NFSDIRECTIO, M_WAITOK);
813 			t_iov = malloc(sizeof(struct iovec), M_NFSDIRECTIO, M_WAITOK);
814 			t_iov->iov_base = malloc(size, M_NFSDIRECTIO, M_WAITOK);
815 			t_iov->iov_len = size;
816 			t_uio->uio_iov = t_iov;
817 			t_uio->uio_iovcnt = 1;
818 			t_uio->uio_offset = uiop->uio_offset;
819 			t_uio->uio_resid = size;
820 			t_uio->uio_segflg = UIO_SYSSPACE;
821 			t_uio->uio_rw = UIO_WRITE;
822 			t_uio->uio_td = td;
823 			bcopy(uiop->uio_iov->iov_base, t_iov->iov_base, size);
824 			bp->b_flags |= B_DIRECT;
825 			bp->b_iocmd = BIO_WRITE;
826 			if (cred != NOCRED) {
827 				crhold(cred);
828 				bp->b_wcred = cred;
829 			} else
830 				bp->b_wcred = NOCRED;
831 			bp->b_caller1 = (void *)t_uio;
832 			bp->b_vp = vp;
833 			error = ncl_asyncio(nmp, bp, NOCRED, td);
834 			if (error) {
835 				free(t_iov->iov_base, M_NFSDIRECTIO);
836 				free(t_iov, M_NFSDIRECTIO);
837 				free(t_uio, M_NFSDIRECTIO);
838 				bp->b_vp = NULL;
839 				relpbuf(bp, &ncl_pbuf_freecnt);
840 				if (error == EINTR)
841 					return (error);
842 				goto do_sync;
843 			}
844 			uiop->uio_offset += size;
845 			uiop->uio_resid -= size;
846 			if (uiop->uio_iov->iov_len <= size) {
847 				uiop->uio_iovcnt--;
848 				uiop->uio_iov++;
849 			} else {
850 				uiop->uio_iov->iov_base =
851 					(char *)uiop->uio_iov->iov_base + size;
852 				uiop->uio_iov->iov_len -= size;
853 			}
854 		}
855 	}
856 	return (0);
857 }
858 
859 /*
860  * Vnode op for write using bio
861  */
862 int
863 ncl_write(struct vop_write_args *ap)
864 {
865 	int biosize;
866 	struct uio *uio = ap->a_uio;
867 	struct thread *td = uio->uio_td;
868 	struct vnode *vp = ap->a_vp;
869 	struct nfsnode *np = VTONFS(vp);
870 	struct ucred *cred = ap->a_cred;
871 	int ioflag = ap->a_ioflag;
872 	struct buf *bp;
873 	struct vattr vattr;
874 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
875 	daddr_t lbn;
876 	int bcount;
877 	int n, on, error = 0;
878 	off_t tmp_off;
879 
880 	KASSERT(uio->uio_rw == UIO_WRITE, ("ncl_write mode"));
881 	KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
882 	    ("ncl_write proc"));
883 	if (vp->v_type != VREG)
884 		return (EIO);
885 	mtx_lock(&np->n_mtx);
886 	if (np->n_flag & NWRITEERR) {
887 		np->n_flag &= ~NWRITEERR;
888 		mtx_unlock(&np->n_mtx);
889 		return (np->n_error);
890 	} else
891 		mtx_unlock(&np->n_mtx);
892 	mtx_lock(&nmp->nm_mtx);
893 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
894 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
895 		mtx_unlock(&nmp->nm_mtx);
896 		(void)ncl_fsinfo(nmp, vp, cred, td);
897 		mtx_lock(&nmp->nm_mtx);
898 	}
899 	if (nmp->nm_wsize == 0)
900 		(void) newnfs_iosize(nmp);
901 	mtx_unlock(&nmp->nm_mtx);
902 
903 	/*
904 	 * Synchronously flush pending buffers if we are in synchronous
905 	 * mode or if we are appending.
906 	 */
907 	if (ioflag & (IO_APPEND | IO_SYNC)) {
908 		mtx_lock(&np->n_mtx);
909 		if (np->n_flag & NMODIFIED) {
910 			mtx_unlock(&np->n_mtx);
911 #ifdef notyet /* Needs matching nonblock semantics elsewhere, too. */
912 			/*
913 			 * Require non-blocking, synchronous writes to
914 			 * dirty files to inform the program it needs
915 			 * to fsync(2) explicitly.
916 			 */
917 			if (ioflag & IO_NDELAY)
918 				return (EAGAIN);
919 #endif
920 flush_and_restart:
921 			np->n_attrstamp = 0;
922 			KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
923 			error = ncl_vinvalbuf(vp, V_SAVE, td, 1);
924 			if (error)
925 				return (error);
926 		} else
927 			mtx_unlock(&np->n_mtx);
928 	}
929 
930 	/*
931 	 * If IO_APPEND then load uio_offset.  We restart here if we cannot
932 	 * get the append lock.
933 	 */
934 	if (ioflag & IO_APPEND) {
935 		np->n_attrstamp = 0;
936 		KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
937 		error = VOP_GETATTR(vp, &vattr, cred);
938 		if (error)
939 			return (error);
940 		mtx_lock(&np->n_mtx);
941 		uio->uio_offset = np->n_size;
942 		mtx_unlock(&np->n_mtx);
943 	}
944 
945 	if (uio->uio_offset < 0)
946 		return (EINVAL);
947 	tmp_off = uio->uio_offset + uio->uio_resid;
948 	if (tmp_off > nmp->nm_maxfilesize || tmp_off < uio->uio_offset)
949 		return (EFBIG);
950 	if (uio->uio_resid == 0)
951 		return (0);
952 
953 	if (newnfs_directio_enable && (ioflag & IO_DIRECT) && vp->v_type == VREG)
954 		return nfs_directio_write(vp, uio, cred, ioflag);
955 
956 	/*
957 	 * Maybe this should be above the vnode op call, but so long as
958 	 * file servers have no limits, i don't think it matters
959 	 */
960 	if (vn_rlimit_fsize(vp, uio, td))
961 		return (EFBIG);
962 
963 	biosize = vp->v_bufobj.bo_bsize;
964 	/*
965 	 * Find all of this file's B_NEEDCOMMIT buffers.  If our writes
966 	 * would exceed the local maximum per-file write commit size when
967 	 * combined with those, we must decide whether to flush,
968 	 * go synchronous, or return error.  We don't bother checking
969 	 * IO_UNIT -- we just make all writes atomic anyway, as there's
970 	 * no point optimizing for something that really won't ever happen.
971 	 */
972 	if (!(ioflag & IO_SYNC)) {
973 		int nflag;
974 
975 		mtx_lock(&np->n_mtx);
976 		nflag = np->n_flag;
977 		mtx_unlock(&np->n_mtx);
978 		int needrestart = 0;
979 		if (nmp->nm_wcommitsize < uio->uio_resid) {
980 			/*
981 			 * If this request could not possibly be completed
982 			 * without exceeding the maximum outstanding write
983 			 * commit size, see if we can convert it into a
984 			 * synchronous write operation.
985 			 */
986 			if (ioflag & IO_NDELAY)
987 				return (EAGAIN);
988 			ioflag |= IO_SYNC;
989 			if (nflag & NMODIFIED)
990 				needrestart = 1;
991 		} else if (nflag & NMODIFIED) {
992 			int wouldcommit = 0;
993 			BO_LOCK(&vp->v_bufobj);
994 			if (vp->v_bufobj.bo_dirty.bv_cnt != 0) {
995 				TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd,
996 				    b_bobufs) {
997 					if (bp->b_flags & B_NEEDCOMMIT)
998 						wouldcommit += bp->b_bcount;
999 				}
1000 			}
1001 			BO_UNLOCK(&vp->v_bufobj);
1002 			/*
1003 			 * Since we're not operating synchronously and
1004 			 * bypassing the buffer cache, we are in a commit
1005 			 * and holding all of these buffers whether
1006 			 * transmitted or not.  If not limited, this
1007 			 * will lead to the buffer cache deadlocking,
1008 			 * as no one else can flush our uncommitted buffers.
1009 			 */
1010 			wouldcommit += uio->uio_resid;
1011 			/*
1012 			 * If we would initially exceed the maximum
1013 			 * outstanding write commit size, flush and restart.
1014 			 */
1015 			if (wouldcommit > nmp->nm_wcommitsize)
1016 				needrestart = 1;
1017 		}
1018 		if (needrestart)
1019 			goto flush_and_restart;
1020 	}
1021 
1022 	do {
1023 		NFSINCRGLOBAL(newnfsstats.biocache_writes);
1024 		lbn = uio->uio_offset / biosize;
1025 		on = uio->uio_offset & (biosize-1);
1026 		n = min((unsigned)(biosize - on), uio->uio_resid);
1027 again:
1028 		/*
1029 		 * Handle direct append and file extension cases, calculate
1030 		 * unaligned buffer size.
1031 		 */
1032 		mtx_lock(&np->n_mtx);
1033 		if (uio->uio_offset == np->n_size && n) {
1034 			mtx_unlock(&np->n_mtx);
1035 			/*
1036 			 * Get the buffer (in its pre-append state to maintain
1037 			 * B_CACHE if it was previously set).  Resize the
1038 			 * nfsnode after we have locked the buffer to prevent
1039 			 * readers from reading garbage.
1040 			 */
1041 			bcount = on;
1042 			bp = nfs_getcacheblk(vp, lbn, bcount, td);
1043 
1044 			if (bp != NULL) {
1045 				long save;
1046 
1047 				mtx_lock(&np->n_mtx);
1048 				np->n_size = uio->uio_offset + n;
1049 				np->n_flag |= NMODIFIED;
1050 				vnode_pager_setsize(vp, np->n_size);
1051 				mtx_unlock(&np->n_mtx);
1052 
1053 				save = bp->b_flags & B_CACHE;
1054 				bcount += n;
1055 				allocbuf(bp, bcount);
1056 				bp->b_flags |= save;
1057 			}
1058 		} else {
1059 			/*
1060 			 * Obtain the locked cache block first, and then
1061 			 * adjust the file's size as appropriate.
1062 			 */
1063 			bcount = on + n;
1064 			if ((off_t)lbn * biosize + bcount < np->n_size) {
1065 				if ((off_t)(lbn + 1) * biosize < np->n_size)
1066 					bcount = biosize;
1067 				else
1068 					bcount = np->n_size - (off_t)lbn * biosize;
1069 			}
1070 			mtx_unlock(&np->n_mtx);
1071 			bp = nfs_getcacheblk(vp, lbn, bcount, td);
1072 			mtx_lock(&np->n_mtx);
1073 			if (uio->uio_offset + n > np->n_size) {
1074 				np->n_size = uio->uio_offset + n;
1075 				np->n_flag |= NMODIFIED;
1076 				vnode_pager_setsize(vp, np->n_size);
1077 			}
1078 			mtx_unlock(&np->n_mtx);
1079 		}
1080 
1081 		if (!bp) {
1082 			error = newnfs_sigintr(nmp, td);
1083 			if (!error)
1084 				error = EINTR;
1085 			break;
1086 		}
1087 
1088 		/*
1089 		 * Issue a READ if B_CACHE is not set.  In special-append
1090 		 * mode, B_CACHE is based on the buffer prior to the write
1091 		 * op and is typically set, avoiding the read.  If a read
1092 		 * is required in special append mode, the server will
1093 		 * probably send us a short-read since we extended the file
1094 		 * on our end, resulting in b_resid == 0 and, thusly,
1095 		 * B_CACHE getting set.
1096 		 *
1097 		 * We can also avoid issuing the read if the write covers
1098 		 * the entire buffer.  We have to make sure the buffer state
1099 		 * is reasonable in this case since we will not be initiating
1100 		 * I/O.  See the comments in kern/vfs_bio.c's getblk() for
1101 		 * more information.
1102 		 *
1103 		 * B_CACHE may also be set due to the buffer being cached
1104 		 * normally.
1105 		 */
1106 
1107 		if (on == 0 && n == bcount) {
1108 			bp->b_flags |= B_CACHE;
1109 			bp->b_flags &= ~B_INVAL;
1110 			bp->b_ioflags &= ~BIO_ERROR;
1111 		}
1112 
1113 		if ((bp->b_flags & B_CACHE) == 0) {
1114 			bp->b_iocmd = BIO_READ;
1115 			vfs_busy_pages(bp, 0);
1116 			error = ncl_doio(vp, bp, cred, td, 0);
1117 			if (error) {
1118 				brelse(bp);
1119 				break;
1120 			}
1121 		}
1122 		if (bp->b_wcred == NOCRED)
1123 			bp->b_wcred = crhold(cred);
1124 		mtx_lock(&np->n_mtx);
1125 		np->n_flag |= NMODIFIED;
1126 		mtx_unlock(&np->n_mtx);
1127 
1128 		/*
1129 		 * If dirtyend exceeds file size, chop it down.  This should
1130 		 * not normally occur but there is an append race where it
1131 		 * might occur XXX, so we log it.
1132 		 *
1133 		 * If the chopping creates a reverse-indexed or degenerate
1134 		 * situation with dirtyoff/end, we 0 both of them.
1135 		 */
1136 
1137 		if (bp->b_dirtyend > bcount) {
1138 			ncl_printf("NFS append race @%lx:%d\n",
1139 			    (long)bp->b_blkno * DEV_BSIZE,
1140 			    bp->b_dirtyend - bcount);
1141 			bp->b_dirtyend = bcount;
1142 		}
1143 
1144 		if (bp->b_dirtyoff >= bp->b_dirtyend)
1145 			bp->b_dirtyoff = bp->b_dirtyend = 0;
1146 
1147 		/*
1148 		 * If the new write will leave a contiguous dirty
1149 		 * area, just update the b_dirtyoff and b_dirtyend,
1150 		 * otherwise force a write rpc of the old dirty area.
1151 		 *
1152 		 * While it is possible to merge discontiguous writes due to
1153 		 * our having a B_CACHE buffer ( and thus valid read data
1154 		 * for the hole), we don't because it could lead to
1155 		 * significant cache coherency problems with multiple clients,
1156 		 * especially if locking is implemented later on.
1157 		 *
1158 		 * as an optimization we could theoretically maintain
1159 		 * a linked list of discontinuous areas, but we would still
1160 		 * have to commit them separately so there isn't much
1161 		 * advantage to it except perhaps a bit of asynchronization.
1162 		 */
1163 
1164 		if (bp->b_dirtyend > 0 &&
1165 		    (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) {
1166 			if (bwrite(bp) == EINTR) {
1167 				error = EINTR;
1168 				break;
1169 			}
1170 			goto again;
1171 		}
1172 
1173 		error = uiomove((char *)bp->b_data + on, n, uio);
1174 
1175 		/*
1176 		 * Since this block is being modified, it must be written
1177 		 * again and not just committed.  Since write clustering does
1178 		 * not work for the stage 1 data write, only the stage 2
1179 		 * commit rpc, we have to clear B_CLUSTEROK as well.
1180 		 */
1181 		bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1182 
1183 		if (error) {
1184 			bp->b_ioflags |= BIO_ERROR;
1185 			brelse(bp);
1186 			break;
1187 		}
1188 
1189 		/*
1190 		 * Only update dirtyoff/dirtyend if not a degenerate
1191 		 * condition.
1192 		 */
1193 		if (n) {
1194 			if (bp->b_dirtyend > 0) {
1195 				bp->b_dirtyoff = min(on, bp->b_dirtyoff);
1196 				bp->b_dirtyend = max((on + n), bp->b_dirtyend);
1197 			} else {
1198 				bp->b_dirtyoff = on;
1199 				bp->b_dirtyend = on + n;
1200 			}
1201 			vfs_bio_set_valid(bp, on, n);
1202 		}
1203 
1204 		/*
1205 		 * If IO_SYNC do bwrite().
1206 		 *
1207 		 * IO_INVAL appears to be unused.  The idea appears to be
1208 		 * to turn off caching in this case.  Very odd.  XXX
1209 		 */
1210 		if ((ioflag & IO_SYNC)) {
1211 			if (ioflag & IO_INVAL)
1212 				bp->b_flags |= B_NOCACHE;
1213 			error = bwrite(bp);
1214 			if (error)
1215 				break;
1216 		} else if ((n + on) == biosize) {
1217 			bp->b_flags |= B_ASYNC;
1218 			(void) ncl_writebp(bp, 0, NULL);
1219 		} else {
1220 			bdwrite(bp);
1221 		}
1222 	} while (uio->uio_resid > 0 && n > 0);
1223 
1224 	return (error);
1225 }
1226 
1227 /*
1228  * Get an nfs cache block.
1229  *
1230  * Allocate a new one if the block isn't currently in the cache
1231  * and return the block marked busy. If the calling process is
1232  * interrupted by a signal for an interruptible mount point, return
1233  * NULL.
1234  *
1235  * The caller must carefully deal with the possible B_INVAL state of
1236  * the buffer.  ncl_doio() clears B_INVAL (and ncl_asyncio() clears it
1237  * indirectly), so synchronous reads can be issued without worrying about
1238  * the B_INVAL state.  We have to be a little more careful when dealing
1239  * with writes (see comments in nfs_write()) when extending a file past
1240  * its EOF.
1241  */
1242 static struct buf *
1243 nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size, struct thread *td)
1244 {
1245 	struct buf *bp;
1246 	struct mount *mp;
1247 	struct nfsmount *nmp;
1248 
1249 	mp = vp->v_mount;
1250 	nmp = VFSTONFS(mp);
1251 
1252 	if (nmp->nm_flag & NFSMNT_INT) {
1253  		sigset_t oldset;
1254 
1255  		newnfs_set_sigmask(td, &oldset);
1256 		bp = getblk(vp, bn, size, NFS_PCATCH, 0, 0);
1257  		newnfs_restore_sigmask(td, &oldset);
1258 		while (bp == NULL) {
1259 			if (newnfs_sigintr(nmp, td))
1260 				return (NULL);
1261 			bp = getblk(vp, bn, size, 0, 2 * hz, 0);
1262 		}
1263 	} else {
1264 		bp = getblk(vp, bn, size, 0, 0, 0);
1265 	}
1266 
1267 	if (vp->v_type == VREG)
1268 		bp->b_blkno = bn * (vp->v_bufobj.bo_bsize / DEV_BSIZE);
1269 	return (bp);
1270 }
1271 
1272 /*
1273  * Flush and invalidate all dirty buffers. If another process is already
1274  * doing the flush, just wait for completion.
1275  */
1276 int
1277 ncl_vinvalbuf(struct vnode *vp, int flags, struct thread *td, int intrflg)
1278 {
1279 	struct nfsnode *np = VTONFS(vp);
1280 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
1281 	int error = 0, slpflag, slptimeo;
1282  	int old_lock = 0;
1283 
1284 	ASSERT_VOP_LOCKED(vp, "ncl_vinvalbuf");
1285 
1286 	if ((nmp->nm_flag & NFSMNT_INT) == 0)
1287 		intrflg = 0;
1288 	if ((nmp->nm_mountp->mnt_kern_flag & MNTK_UNMOUNTF))
1289 		intrflg = 1;
1290 	if (intrflg) {
1291 		slpflag = NFS_PCATCH;
1292 		slptimeo = 2 * hz;
1293 	} else {
1294 		slpflag = 0;
1295 		slptimeo = 0;
1296 	}
1297 
1298 	old_lock = ncl_upgrade_vnlock(vp);
1299 	if (vp->v_iflag & VI_DOOMED) {
1300 		/*
1301 		 * Since vgonel() uses the generic vinvalbuf() to flush
1302 		 * dirty buffers and it does not call this function, it
1303 		 * is safe to just return OK when VI_DOOMED is set.
1304 		 */
1305 		ncl_downgrade_vnlock(vp, old_lock);
1306 		return (0);
1307 	}
1308 
1309 	/*
1310 	 * Now, flush as required.
1311 	 */
1312 	if ((flags & V_SAVE) && (vp->v_bufobj.bo_object != NULL)) {
1313 		VM_OBJECT_LOCK(vp->v_bufobj.bo_object);
1314 		vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC);
1315 		VM_OBJECT_UNLOCK(vp->v_bufobj.bo_object);
1316 		/*
1317 		 * If the page clean was interrupted, fail the invalidation.
1318 		 * Not doing so, we run the risk of losing dirty pages in the
1319 		 * vinvalbuf() call below.
1320 		 */
1321 		if (intrflg && (error = newnfs_sigintr(nmp, td)))
1322 			goto out;
1323 	}
1324 
1325 	error = vinvalbuf(vp, flags, slpflag, 0);
1326 	while (error) {
1327 		if (intrflg && (error = newnfs_sigintr(nmp, td)))
1328 			goto out;
1329 		error = vinvalbuf(vp, flags, 0, slptimeo);
1330 	}
1331 	mtx_lock(&np->n_mtx);
1332 	if (np->n_directio_asyncwr == 0)
1333 		np->n_flag &= ~NMODIFIED;
1334 	mtx_unlock(&np->n_mtx);
1335 out:
1336 	ncl_downgrade_vnlock(vp, old_lock);
1337 	return error;
1338 }
1339 
1340 /*
1341  * Initiate asynchronous I/O. Return an error if no nfsiods are available.
1342  * This is mainly to avoid queueing async I/O requests when the nfsiods
1343  * are all hung on a dead server.
1344  *
1345  * Note: ncl_asyncio() does not clear (BIO_ERROR|B_INVAL) but when the bp
1346  * is eventually dequeued by the async daemon, ncl_doio() *will*.
1347  */
1348 int
1349 ncl_asyncio(struct nfsmount *nmp, struct buf *bp, struct ucred *cred, struct thread *td)
1350 {
1351 	int iod;
1352 	int gotiod;
1353 	int slpflag = 0;
1354 	int slptimeo = 0;
1355 	int error, error2;
1356 
1357 	/*
1358 	 * Commits are usually short and sweet so lets save some cpu and
1359 	 * leave the async daemons for more important rpc's (such as reads
1360 	 * and writes).
1361 	 */
1362 	mtx_lock(&ncl_iod_mutex);
1363 	if (bp->b_iocmd == BIO_WRITE && (bp->b_flags & B_NEEDCOMMIT) &&
1364 	    (nmp->nm_bufqiods > ncl_numasync / 2)) {
1365 		mtx_unlock(&ncl_iod_mutex);
1366 		return(EIO);
1367 	}
1368 again:
1369 	if (nmp->nm_flag & NFSMNT_INT)
1370 		slpflag = NFS_PCATCH;
1371 	gotiod = FALSE;
1372 
1373 	/*
1374 	 * Find a free iod to process this request.
1375 	 */
1376 	for (iod = 0; iod < ncl_numasync; iod++)
1377 		if (ncl_iodwant[iod] == NFSIOD_AVAILABLE) {
1378 			gotiod = TRUE;
1379 			break;
1380 		}
1381 
1382 	/*
1383 	 * Try to create one if none are free.
1384 	 */
1385 	if (!gotiod)
1386 		ncl_nfsiodnew();
1387 	else {
1388 		/*
1389 		 * Found one, so wake it up and tell it which
1390 		 * mount to process.
1391 		 */
1392 		NFS_DPF(ASYNCIO, ("ncl_asyncio: waking iod %d for mount %p\n",
1393 		    iod, nmp));
1394 		ncl_iodwant[iod] = NFSIOD_NOT_AVAILABLE;
1395 		ncl_iodmount[iod] = nmp;
1396 		nmp->nm_bufqiods++;
1397 		wakeup(&ncl_iodwant[iod]);
1398 	}
1399 
1400 	/*
1401 	 * If none are free, we may already have an iod working on this mount
1402 	 * point.  If so, it will process our request.
1403 	 */
1404 	if (!gotiod) {
1405 		if (nmp->nm_bufqiods > 0) {
1406 			NFS_DPF(ASYNCIO,
1407 				("ncl_asyncio: %d iods are already processing mount %p\n",
1408 				 nmp->nm_bufqiods, nmp));
1409 			gotiod = TRUE;
1410 		}
1411 	}
1412 
1413 	/*
1414 	 * If we have an iod which can process the request, then queue
1415 	 * the buffer.
1416 	 */
1417 	if (gotiod) {
1418 		/*
1419 		 * Ensure that the queue never grows too large.  We still want
1420 		 * to asynchronize so we block rather then return EIO.
1421 		 */
1422 		while (nmp->nm_bufqlen >= 2*ncl_numasync) {
1423 			NFS_DPF(ASYNCIO,
1424 				("ncl_asyncio: waiting for mount %p queue to drain\n", nmp));
1425 			nmp->nm_bufqwant = TRUE;
1426  			error = newnfs_msleep(td, &nmp->nm_bufq,
1427 			    &ncl_iod_mutex, slpflag | PRIBIO, "nfsaio",
1428   			   slptimeo);
1429 			if (error) {
1430 				error2 = newnfs_sigintr(nmp, td);
1431 				if (error2) {
1432 					mtx_unlock(&ncl_iod_mutex);
1433 					return (error2);
1434 				}
1435 				if (slpflag == NFS_PCATCH) {
1436 					slpflag = 0;
1437 					slptimeo = 2 * hz;
1438 				}
1439 			}
1440 			/*
1441 			 * We might have lost our iod while sleeping,
1442 			 * so check and loop if nescessary.
1443 			 */
1444 			goto again;
1445 		}
1446 
1447 		/* We might have lost our nfsiod */
1448 		if (nmp->nm_bufqiods == 0) {
1449 			NFS_DPF(ASYNCIO,
1450 				("ncl_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
1451 			goto again;
1452 		}
1453 
1454 		if (bp->b_iocmd == BIO_READ) {
1455 			if (bp->b_rcred == NOCRED && cred != NOCRED)
1456 				bp->b_rcred = crhold(cred);
1457 		} else {
1458 			if (bp->b_wcred == NOCRED && cred != NOCRED)
1459 				bp->b_wcred = crhold(cred);
1460 		}
1461 
1462 		if (bp->b_flags & B_REMFREE)
1463 			bremfreef(bp);
1464 		BUF_KERNPROC(bp);
1465 		TAILQ_INSERT_TAIL(&nmp->nm_bufq, bp, b_freelist);
1466 		nmp->nm_bufqlen++;
1467 		if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
1468 			mtx_lock(&(VTONFS(bp->b_vp))->n_mtx);
1469 			VTONFS(bp->b_vp)->n_flag |= NMODIFIED;
1470 			VTONFS(bp->b_vp)->n_directio_asyncwr++;
1471 			mtx_unlock(&(VTONFS(bp->b_vp))->n_mtx);
1472 		}
1473 		mtx_unlock(&ncl_iod_mutex);
1474 		return (0);
1475 	}
1476 
1477 	mtx_unlock(&ncl_iod_mutex);
1478 
1479 	/*
1480 	 * All the iods are busy on other mounts, so return EIO to
1481 	 * force the caller to process the i/o synchronously.
1482 	 */
1483 	NFS_DPF(ASYNCIO, ("ncl_asyncio: no iods available, i/o is synchronous\n"));
1484 	return (EIO);
1485 }
1486 
1487 void
1488 ncl_doio_directwrite(struct buf *bp)
1489 {
1490 	int iomode, must_commit;
1491 	struct uio *uiop = (struct uio *)bp->b_caller1;
1492 	char *iov_base = uiop->uio_iov->iov_base;
1493 
1494 	iomode = NFSWRITE_FILESYNC;
1495 	uiop->uio_td = NULL; /* NULL since we're in nfsiod */
1496 	ncl_writerpc(bp->b_vp, uiop, bp->b_wcred, &iomode, &must_commit, 0);
1497 	KASSERT((must_commit == 0), ("ncl_doio_directwrite: Did not commit write"));
1498 	free(iov_base, M_NFSDIRECTIO);
1499 	free(uiop->uio_iov, M_NFSDIRECTIO);
1500 	free(uiop, M_NFSDIRECTIO);
1501 	if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
1502 		struct nfsnode *np = VTONFS(bp->b_vp);
1503 		mtx_lock(&np->n_mtx);
1504 		np->n_directio_asyncwr--;
1505 		if (np->n_directio_asyncwr == 0) {
1506 			np->n_flag &= ~NMODIFIED;
1507 			if ((np->n_flag & NFSYNCWAIT)) {
1508 				np->n_flag &= ~NFSYNCWAIT;
1509 				wakeup((caddr_t)&np->n_directio_asyncwr);
1510 			}
1511 		}
1512 		mtx_unlock(&np->n_mtx);
1513 	}
1514 	bp->b_vp = NULL;
1515 	relpbuf(bp, &ncl_pbuf_freecnt);
1516 }
1517 
1518 /*
1519  * Do an I/O operation to/from a cache block. This may be called
1520  * synchronously or from an nfsiod.
1521  */
1522 int
1523 ncl_doio(struct vnode *vp, struct buf *bp, struct ucred *cr, struct thread *td,
1524     int called_from_strategy)
1525 {
1526 	struct uio *uiop;
1527 	struct nfsnode *np;
1528 	struct nfsmount *nmp;
1529 	int error = 0, iomode, must_commit = 0;
1530 	struct uio uio;
1531 	struct iovec io;
1532 	struct proc *p = td ? td->td_proc : NULL;
1533 	uint8_t	iocmd;
1534 
1535 	np = VTONFS(vp);
1536 	nmp = VFSTONFS(vp->v_mount);
1537 	uiop = &uio;
1538 	uiop->uio_iov = &io;
1539 	uiop->uio_iovcnt = 1;
1540 	uiop->uio_segflg = UIO_SYSSPACE;
1541 	uiop->uio_td = td;
1542 
1543 	/*
1544 	 * clear BIO_ERROR and B_INVAL state prior to initiating the I/O.  We
1545 	 * do this here so we do not have to do it in all the code that
1546 	 * calls us.
1547 	 */
1548 	bp->b_flags &= ~B_INVAL;
1549 	bp->b_ioflags &= ~BIO_ERROR;
1550 
1551 	KASSERT(!(bp->b_flags & B_DONE), ("ncl_doio: bp %p already marked done", bp));
1552 	iocmd = bp->b_iocmd;
1553 	if (iocmd == BIO_READ) {
1554 	    io.iov_len = uiop->uio_resid = bp->b_bcount;
1555 	    io.iov_base = bp->b_data;
1556 	    uiop->uio_rw = UIO_READ;
1557 
1558 	    switch (vp->v_type) {
1559 	    case VREG:
1560 		uiop->uio_offset = ((off_t)bp->b_blkno) * DEV_BSIZE;
1561 		NFSINCRGLOBAL(newnfsstats.read_bios);
1562 		error = ncl_readrpc(vp, uiop, cr);
1563 
1564 		if (!error) {
1565 		    if (uiop->uio_resid) {
1566 			/*
1567 			 * If we had a short read with no error, we must have
1568 			 * hit a file hole.  We should zero-fill the remainder.
1569 			 * This can also occur if the server hits the file EOF.
1570 			 *
1571 			 * Holes used to be able to occur due to pending
1572 			 * writes, but that is not possible any longer.
1573 			 */
1574 			int nread = bp->b_bcount - uiop->uio_resid;
1575 			int left  = uiop->uio_resid;
1576 
1577 			if (left > 0)
1578 				bzero((char *)bp->b_data + nread, left);
1579 			uiop->uio_resid = 0;
1580 		    }
1581 		}
1582 		/* ASSERT_VOP_LOCKED(vp, "ncl_doio"); */
1583 		if (p && (vp->v_vflag & VV_TEXT)) {
1584 			mtx_lock(&np->n_mtx);
1585 			if (NFS_TIMESPEC_COMPARE(&np->n_mtime, &np->n_vattr.na_mtime)) {
1586 				mtx_unlock(&np->n_mtx);
1587 				PROC_LOCK(p);
1588 				killproc(p, "text file modification");
1589 				PROC_UNLOCK(p);
1590 			} else
1591 				mtx_unlock(&np->n_mtx);
1592 		}
1593 		break;
1594 	    case VLNK:
1595 		uiop->uio_offset = (off_t)0;
1596 		NFSINCRGLOBAL(newnfsstats.readlink_bios);
1597 		error = ncl_readlinkrpc(vp, uiop, cr);
1598 		break;
1599 	    case VDIR:
1600 		NFSINCRGLOBAL(newnfsstats.readdir_bios);
1601 		uiop->uio_offset = ((u_quad_t)bp->b_lblkno) * NFS_DIRBLKSIZ;
1602 		if ((nmp->nm_flag & NFSMNT_RDIRPLUS) != 0) {
1603 			error = ncl_readdirplusrpc(vp, uiop, cr, td);
1604 			if (error == NFSERR_NOTSUPP)
1605 				nmp->nm_flag &= ~NFSMNT_RDIRPLUS;
1606 		}
1607 		if ((nmp->nm_flag & NFSMNT_RDIRPLUS) == 0)
1608 			error = ncl_readdirrpc(vp, uiop, cr, td);
1609 		/*
1610 		 * end-of-directory sets B_INVAL but does not generate an
1611 		 * error.
1612 		 */
1613 		if (error == 0 && uiop->uio_resid == bp->b_bcount)
1614 			bp->b_flags |= B_INVAL;
1615 		break;
1616 	    default:
1617 		ncl_printf("ncl_doio:  type %x unexpected\n", vp->v_type);
1618 		break;
1619 	    };
1620 	    if (error) {
1621 		bp->b_ioflags |= BIO_ERROR;
1622 		bp->b_error = error;
1623 	    }
1624 	} else {
1625 	    /*
1626 	     * If we only need to commit, try to commit
1627 	     */
1628 	    if (bp->b_flags & B_NEEDCOMMIT) {
1629 		    int retv;
1630 		    off_t off;
1631 
1632 		    off = ((u_quad_t)bp->b_blkno) * DEV_BSIZE + bp->b_dirtyoff;
1633 		    retv = ncl_commit(vp, off, bp->b_dirtyend-bp->b_dirtyoff,
1634 			bp->b_wcred, td);
1635 		    if (retv == 0) {
1636 			    bp->b_dirtyoff = bp->b_dirtyend = 0;
1637 			    bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1638 			    bp->b_resid = 0;
1639 			    bufdone(bp);
1640 			    return (0);
1641 		    }
1642 		    if (retv == NFSERR_STALEWRITEVERF) {
1643 			    ncl_clearcommit(vp->v_mount);
1644 		    }
1645 	    }
1646 
1647 	    /*
1648 	     * Setup for actual write
1649 	     */
1650 	    mtx_lock(&np->n_mtx);
1651 	    if ((off_t)bp->b_blkno * DEV_BSIZE + bp->b_dirtyend > np->n_size)
1652 		bp->b_dirtyend = np->n_size - (off_t)bp->b_blkno * DEV_BSIZE;
1653 	    mtx_unlock(&np->n_mtx);
1654 
1655 	    if (bp->b_dirtyend > bp->b_dirtyoff) {
1656 		io.iov_len = uiop->uio_resid = bp->b_dirtyend
1657 		    - bp->b_dirtyoff;
1658 		uiop->uio_offset = (off_t)bp->b_blkno * DEV_BSIZE
1659 		    + bp->b_dirtyoff;
1660 		io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
1661 		uiop->uio_rw = UIO_WRITE;
1662 		NFSINCRGLOBAL(newnfsstats.write_bios);
1663 
1664 		if ((bp->b_flags & (B_ASYNC | B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == B_ASYNC)
1665 		    iomode = NFSWRITE_UNSTABLE;
1666 		else
1667 		    iomode = NFSWRITE_FILESYNC;
1668 
1669 		error = ncl_writerpc(vp, uiop, cr, &iomode, &must_commit,
1670 		    called_from_strategy);
1671 
1672 		/*
1673 		 * When setting B_NEEDCOMMIT also set B_CLUSTEROK to try
1674 		 * to cluster the buffers needing commit.  This will allow
1675 		 * the system to submit a single commit rpc for the whole
1676 		 * cluster.  We can do this even if the buffer is not 100%
1677 		 * dirty (relative to the NFS blocksize), so we optimize the
1678 		 * append-to-file-case.
1679 		 *
1680 		 * (when clearing B_NEEDCOMMIT, B_CLUSTEROK must also be
1681 		 * cleared because write clustering only works for commit
1682 		 * rpc's, not for the data portion of the write).
1683 		 */
1684 
1685 		if (!error && iomode == NFSWRITE_UNSTABLE) {
1686 		    bp->b_flags |= B_NEEDCOMMIT;
1687 		    if (bp->b_dirtyoff == 0
1688 			&& bp->b_dirtyend == bp->b_bcount)
1689 			bp->b_flags |= B_CLUSTEROK;
1690 		} else {
1691 		    bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1692 		}
1693 
1694 		/*
1695 		 * For an interrupted write, the buffer is still valid
1696 		 * and the write hasn't been pushed to the server yet,
1697 		 * so we can't set BIO_ERROR and report the interruption
1698 		 * by setting B_EINTR. For the B_ASYNC case, B_EINTR
1699 		 * is not relevant, so the rpc attempt is essentially
1700 		 * a noop.  For the case of a V3 write rpc not being
1701 		 * committed to stable storage, the block is still
1702 		 * dirty and requires either a commit rpc or another
1703 		 * write rpc with iomode == NFSV3WRITE_FILESYNC before
1704 		 * the block is reused. This is indicated by setting
1705 		 * the B_DELWRI and B_NEEDCOMMIT flags.
1706 		 *
1707 		 * EIO is returned by ncl_writerpc() to indicate a recoverable
1708 		 * write error and is handled as above, except that
1709 		 * B_EINTR isn't set. One cause of this is a stale stateid
1710 		 * error for the RPC that indicates recovery is required,
1711 		 * when called with called_from_strategy != 0.
1712 		 *
1713 		 * If the buffer is marked B_PAGING, it does not reside on
1714 		 * the vp's paging queues so we cannot call bdirty().  The
1715 		 * bp in this case is not an NFS cache block so we should
1716 		 * be safe. XXX
1717 		 *
1718 		 * The logic below breaks up errors into recoverable and
1719 		 * unrecoverable. For the former, we clear B_INVAL|B_NOCACHE
1720 		 * and keep the buffer around for potential write retries.
1721 		 * For the latter (eg ESTALE), we toss the buffer away (B_INVAL)
1722 		 * and save the error in the nfsnode. This is less than ideal
1723 		 * but necessary. Keeping such buffers around could potentially
1724 		 * cause buffer exhaustion eventually (they can never be written
1725 		 * out, so will get constantly be re-dirtied). It also causes
1726 		 * all sorts of vfs panics. For non-recoverable write errors,
1727 		 * also invalidate the attrcache, so we'll be forced to go over
1728 		 * the wire for this object, returning an error to user on next
1729 		 * call (most of the time).
1730 		 */
1731     		if (error == EINTR || error == EIO || error == ETIMEDOUT
1732 		    || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
1733 			int s;
1734 
1735 			s = splbio();
1736 			bp->b_flags &= ~(B_INVAL|B_NOCACHE);
1737 			if ((bp->b_flags & B_PAGING) == 0) {
1738 			    bdirty(bp);
1739 			    bp->b_flags &= ~B_DONE;
1740 			}
1741 			if ((error == EINTR || error == ETIMEDOUT) &&
1742 			    (bp->b_flags & B_ASYNC) == 0)
1743 			    bp->b_flags |= B_EINTR;
1744 			splx(s);
1745 	    	} else {
1746 		    if (error) {
1747 			bp->b_ioflags |= BIO_ERROR;
1748 			bp->b_flags |= B_INVAL;
1749 			bp->b_error = np->n_error = error;
1750 			mtx_lock(&np->n_mtx);
1751 			np->n_flag |= NWRITEERR;
1752 			np->n_attrstamp = 0;
1753 			KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
1754 			mtx_unlock(&np->n_mtx);
1755 		    }
1756 		    bp->b_dirtyoff = bp->b_dirtyend = 0;
1757 		}
1758 	    } else {
1759 		bp->b_resid = 0;
1760 		bufdone(bp);
1761 		return (0);
1762 	    }
1763 	}
1764 	bp->b_resid = uiop->uio_resid;
1765 	if (must_commit)
1766 	    ncl_clearcommit(vp->v_mount);
1767 	bufdone(bp);
1768 	return (error);
1769 }
1770 
1771 /*
1772  * Used to aid in handling ftruncate() operations on the NFS client side.
1773  * Truncation creates a number of special problems for NFS.  We have to
1774  * throw away VM pages and buffer cache buffers that are beyond EOF, and
1775  * we have to properly handle VM pages or (potentially dirty) buffers
1776  * that straddle the truncation point.
1777  */
1778 
1779 int
1780 ncl_meta_setsize(struct vnode *vp, struct ucred *cred, struct thread *td, u_quad_t nsize)
1781 {
1782 	struct nfsnode *np = VTONFS(vp);
1783 	u_quad_t tsize;
1784 	int biosize = vp->v_bufobj.bo_bsize;
1785 	int error = 0;
1786 
1787 	mtx_lock(&np->n_mtx);
1788 	tsize = np->n_size;
1789 	np->n_size = nsize;
1790 	mtx_unlock(&np->n_mtx);
1791 
1792 	if (nsize < tsize) {
1793 		struct buf *bp;
1794 		daddr_t lbn;
1795 		int bufsize;
1796 
1797 		/*
1798 		 * vtruncbuf() doesn't get the buffer overlapping the
1799 		 * truncation point.  We may have a B_DELWRI and/or B_CACHE
1800 		 * buffer that now needs to be truncated.
1801 		 */
1802 		error = vtruncbuf(vp, cred, td, nsize, biosize);
1803 		lbn = nsize / biosize;
1804 		bufsize = nsize & (biosize - 1);
1805 		bp = nfs_getcacheblk(vp, lbn, bufsize, td);
1806  		if (!bp)
1807  			return EINTR;
1808 		if (bp->b_dirtyoff > bp->b_bcount)
1809 			bp->b_dirtyoff = bp->b_bcount;
1810 		if (bp->b_dirtyend > bp->b_bcount)
1811 			bp->b_dirtyend = bp->b_bcount;
1812 		bp->b_flags |= B_RELBUF;  /* don't leave garbage around */
1813 		brelse(bp);
1814 	} else {
1815 		vnode_pager_setsize(vp, nsize);
1816 	}
1817 	return(error);
1818 }
1819 
1820