xref: /freebsd/sys/fs/nfsclient/nfs_clbio.c (revision e9e8876a4d6afc1ad5315faaa191b25121a813d7)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Rick Macklem at The University of Guelph.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)nfs_bio.c	8.9 (Berkeley) 3/30/95
35  */
36 
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
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/rwlock.h>
47 #include <sys/vmmeter.h>
48 #include <sys/vnode.h>
49 
50 #include <vm/vm.h>
51 #include <vm/vm_param.h>
52 #include <vm/vm_extern.h>
53 #include <vm/vm_page.h>
54 #include <vm/vm_object.h>
55 #include <vm/vm_pager.h>
56 #include <vm/vnode_pager.h>
57 
58 #include <fs/nfs/nfsport.h>
59 #include <fs/nfsclient/nfsmount.h>
60 #include <fs/nfsclient/nfs.h>
61 #include <fs/nfsclient/nfsnode.h>
62 #include <fs/nfsclient/nfs_kdtrace.h>
63 
64 extern int newnfs_directio_allow_mmap;
65 extern struct nfsstatsv1 nfsstatsv1;
66 extern struct mtx ncl_iod_mutex;
67 extern int ncl_numasync;
68 extern enum nfsiod_state ncl_iodwant[NFS_MAXASYNCDAEMON];
69 extern struct nfsmount *ncl_iodmount[NFS_MAXASYNCDAEMON];
70 extern int newnfs_directio_enable;
71 extern int nfs_keep_dirty_on_error;
72 
73 uma_zone_t ncl_pbuf_zone;
74 
75 static struct buf *nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size,
76     struct thread *td);
77 static int nfs_directio_write(struct vnode *vp, struct uio *uiop,
78     struct ucred *cred, int ioflag);
79 
80 /*
81  * Vnode op for VM getpages.
82  */
83 SYSCTL_DECL(_vfs_nfs);
84 static int use_buf_pager = 1;
85 SYSCTL_INT(_vfs_nfs, OID_AUTO, use_buf_pager, CTLFLAG_RWTUN,
86     &use_buf_pager, 0,
87     "Use buffer pager instead of direct readrpc call");
88 
89 static daddr_t
90 ncl_gbp_getblkno(struct vnode *vp, vm_ooffset_t off)
91 {
92 
93 	return (off / vp->v_bufobj.bo_bsize);
94 }
95 
96 static int
97 ncl_gbp_getblksz(struct vnode *vp, daddr_t lbn, long *sz)
98 {
99 	struct nfsnode *np;
100 	u_quad_t nsize;
101 	int biosize, bcount;
102 
103 	np = VTONFS(vp);
104 	NFSLOCKNODE(np);
105 	nsize = np->n_size;
106 	NFSUNLOCKNODE(np);
107 
108 	biosize = vp->v_bufobj.bo_bsize;
109 	bcount = biosize;
110 	if ((off_t)lbn * biosize >= nsize)
111 		bcount = 0;
112 	else if ((off_t)(lbn + 1) * biosize > nsize)
113 		bcount = nsize - (off_t)lbn * biosize;
114 	*sz = bcount;
115 	return (0);
116 }
117 
118 int
119 ncl_getpages(struct vop_getpages_args *ap)
120 {
121 	int i, error, nextoff, size, toff, count, npages;
122 	struct uio uio;
123 	struct iovec iov;
124 	vm_offset_t kva;
125 	struct buf *bp;
126 	struct vnode *vp;
127 	struct thread *td;
128 	struct ucred *cred;
129 	struct nfsmount *nmp;
130 	vm_object_t object;
131 	vm_page_t *pages;
132 	struct nfsnode *np;
133 
134 	vp = ap->a_vp;
135 	np = VTONFS(vp);
136 	td = curthread;
137 	cred = curthread->td_ucred;
138 	nmp = VFSTONFS(vp->v_mount);
139 	pages = ap->a_m;
140 	npages = ap->a_count;
141 
142 	if ((object = vp->v_object) == NULL) {
143 		printf("ncl_getpages: called with non-merged cache vnode\n");
144 		return (VM_PAGER_ERROR);
145 	}
146 
147 	if (newnfs_directio_enable && !newnfs_directio_allow_mmap) {
148 		NFSLOCKNODE(np);
149 		if ((np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
150 			NFSUNLOCKNODE(np);
151 			printf("ncl_getpages: called on non-cacheable vnode\n");
152 			return (VM_PAGER_ERROR);
153 		} else
154 			NFSUNLOCKNODE(np);
155 	}
156 
157 	mtx_lock(&nmp->nm_mtx);
158 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
159 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
160 		mtx_unlock(&nmp->nm_mtx);
161 		/* We'll never get here for v4, because we always have fsinfo */
162 		(void)ncl_fsinfo(nmp, vp, cred, td);
163 	} else
164 		mtx_unlock(&nmp->nm_mtx);
165 
166 	if (use_buf_pager)
167 		return (vfs_bio_getpages(vp, pages, npages, ap->a_rbehind,
168 		    ap->a_rahead, ncl_gbp_getblkno, ncl_gbp_getblksz));
169 
170 	/*
171 	 * If the requested page is partially valid, just return it and
172 	 * allow the pager to zero-out the blanks.  Partially valid pages
173 	 * can only occur at the file EOF.
174 	 *
175 	 * XXXGL: is that true for NFS, where short read can occur???
176 	 */
177 	VM_OBJECT_WLOCK(object);
178 	if (!vm_page_none_valid(pages[npages - 1]) && --npages == 0)
179 		goto out;
180 	VM_OBJECT_WUNLOCK(object);
181 
182 	/*
183 	 * We use only the kva address for the buffer, but this is extremely
184 	 * convenient and fast.
185 	 */
186 	bp = uma_zalloc(ncl_pbuf_zone, M_WAITOK);
187 
188 	kva = (vm_offset_t) bp->b_data;
189 	pmap_qenter(kva, pages, npages);
190 	VM_CNT_INC(v_vnodein);
191 	VM_CNT_ADD(v_vnodepgsin, npages);
192 
193 	count = npages << PAGE_SHIFT;
194 	iov.iov_base = (caddr_t) kva;
195 	iov.iov_len = count;
196 	uio.uio_iov = &iov;
197 	uio.uio_iovcnt = 1;
198 	uio.uio_offset = IDX_TO_OFF(pages[0]->pindex);
199 	uio.uio_resid = count;
200 	uio.uio_segflg = UIO_SYSSPACE;
201 	uio.uio_rw = UIO_READ;
202 	uio.uio_td = td;
203 
204 	error = ncl_readrpc(vp, &uio, cred);
205 	pmap_qremove(kva, npages);
206 
207 	uma_zfree(ncl_pbuf_zone, bp);
208 
209 	if (error && (uio.uio_resid == count)) {
210 		printf("ncl_getpages: error %d\n", error);
211 		return (VM_PAGER_ERROR);
212 	}
213 
214 	/*
215 	 * Calculate the number of bytes read and validate only that number
216 	 * of bytes.  Note that due to pending writes, size may be 0.  This
217 	 * does not mean that the remaining data is invalid!
218 	 */
219 
220 	size = count - uio.uio_resid;
221 	VM_OBJECT_WLOCK(object);
222 	for (i = 0, toff = 0; i < npages; i++, toff = nextoff) {
223 		vm_page_t m;
224 		nextoff = toff + PAGE_SIZE;
225 		m = pages[i];
226 
227 		if (nextoff <= size) {
228 			/*
229 			 * Read operation filled an entire page
230 			 */
231 			vm_page_valid(m);
232 			KASSERT(m->dirty == 0,
233 			    ("nfs_getpages: page %p is dirty", m));
234 		} else if (size > toff) {
235 			/*
236 			 * Read operation filled a partial page.
237 			 */
238 			vm_page_invalid(m);
239 			vm_page_set_valid_range(m, 0, size - toff);
240 			KASSERT(m->dirty == 0,
241 			    ("nfs_getpages: page %p is dirty", m));
242 		} else {
243 			/*
244 			 * Read operation was short.  If no error
245 			 * occurred we may have hit a zero-fill
246 			 * section.  We leave valid set to 0, and page
247 			 * is freed by vm_page_readahead_finish() if
248 			 * its index is not equal to requested, or
249 			 * page is zeroed and set valid by
250 			 * vm_pager_get_pages() for requested page.
251 			 */
252 			;
253 		}
254 	}
255 out:
256 	VM_OBJECT_WUNLOCK(object);
257 	if (ap->a_rbehind)
258 		*ap->a_rbehind = 0;
259 	if (ap->a_rahead)
260 		*ap->a_rahead = 0;
261 	return (VM_PAGER_OK);
262 }
263 
264 /*
265  * Vnode op for VM putpages.
266  */
267 int
268 ncl_putpages(struct vop_putpages_args *ap)
269 {
270 	struct uio uio;
271 	struct iovec iov;
272 	int i, error, npages, count;
273 	off_t offset;
274 	int *rtvals;
275 	struct vnode *vp;
276 	struct thread *td;
277 	struct ucred *cred;
278 	struct nfsmount *nmp;
279 	struct nfsnode *np;
280 	vm_page_t *pages;
281 
282 	vp = ap->a_vp;
283 	np = VTONFS(vp);
284 	td = curthread;				/* XXX */
285 	/* Set the cred to n_writecred for the write rpcs. */
286 	if (np->n_writecred != NULL)
287 		cred = crhold(np->n_writecred);
288 	else
289 		cred = crhold(curthread->td_ucred);	/* XXX */
290 	nmp = VFSTONFS(vp->v_mount);
291 	pages = ap->a_m;
292 	count = ap->a_count;
293 	rtvals = ap->a_rtvals;
294 	npages = btoc(count);
295 	offset = IDX_TO_OFF(pages[0]->pindex);
296 
297 	mtx_lock(&nmp->nm_mtx);
298 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
299 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
300 		mtx_unlock(&nmp->nm_mtx);
301 		(void)ncl_fsinfo(nmp, vp, cred, td);
302 	} else
303 		mtx_unlock(&nmp->nm_mtx);
304 
305 	NFSLOCKNODE(np);
306 	if (newnfs_directio_enable && !newnfs_directio_allow_mmap &&
307 	    (np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
308 		NFSUNLOCKNODE(np);
309 		printf("ncl_putpages: called on noncache-able vnode\n");
310 		NFSLOCKNODE(np);
311 	}
312 	/*
313 	 * When putting pages, do not extend file past EOF.
314 	 */
315 	if (offset + count > np->n_size) {
316 		count = np->n_size - offset;
317 		if (count < 0)
318 			count = 0;
319 	}
320 	NFSUNLOCKNODE(np);
321 
322 	for (i = 0; i < npages; i++)
323 		rtvals[i] = VM_PAGER_ERROR;
324 
325 	VM_CNT_INC(v_vnodeout);
326 	VM_CNT_ADD(v_vnodepgsout, count);
327 
328 	iov.iov_base = unmapped_buf;
329 	iov.iov_len = count;
330 	uio.uio_iov = &iov;
331 	uio.uio_iovcnt = 1;
332 	uio.uio_offset = offset;
333 	uio.uio_resid = count;
334 	uio.uio_segflg = UIO_NOCOPY;
335 	uio.uio_rw = UIO_WRITE;
336 	uio.uio_td = td;
337 
338 	error = VOP_WRITE(vp, &uio, vnode_pager_putpages_ioflags(ap->a_sync),
339 	    cred);
340 	crfree(cred);
341 
342 	if (error == 0 || !nfs_keep_dirty_on_error) {
343 		vnode_pager_undirty_pages(pages, rtvals, count - uio.uio_resid,
344 		    np->n_size - offset, npages * PAGE_SIZE);
345 	}
346 	return (rtvals[0]);
347 }
348 
349 /*
350  * For nfs, cache consistency can only be maintained approximately.
351  * Although RFC1094 does not specify the criteria, the following is
352  * believed to be compatible with the reference port.
353  * For nfs:
354  * If the file's modify time on the server has changed since the
355  * last read rpc or you have written to the file,
356  * you may have lost data cache consistency with the
357  * server, so flush all of the file's data out of the cache.
358  * Then force a getattr rpc to ensure that you have up to date
359  * attributes.
360  * NB: This implies that cache data can be read when up to
361  * NFS_ATTRTIMEO seconds out of date. If you find that you need current
362  * attributes this could be forced by setting n_attrstamp to 0 before
363  * the VOP_GETATTR() call.
364  */
365 static inline int
366 nfs_bioread_check_cons(struct vnode *vp, struct thread *td, struct ucred *cred)
367 {
368 	int error = 0;
369 	struct vattr vattr;
370 	struct nfsnode *np = VTONFS(vp);
371 	bool old_lock;
372 
373 	/*
374 	 * Ensure the exclusove access to the node before checking
375 	 * whether the cache is consistent.
376 	 */
377 	old_lock = ncl_excl_start(vp);
378 	NFSLOCKNODE(np);
379 	if (np->n_flag & NMODIFIED) {
380 		NFSUNLOCKNODE(np);
381 		if (vp->v_type != VREG) {
382 			if (vp->v_type != VDIR)
383 				panic("nfs: bioread, not dir");
384 			ncl_invaldir(vp);
385 			error = ncl_vinvalbuf(vp, V_SAVE | V_ALLOWCLEAN, td, 1);
386 			if (error != 0)
387 				goto out;
388 		}
389 		np->n_attrstamp = 0;
390 		KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
391 		error = VOP_GETATTR(vp, &vattr, cred);
392 		if (error)
393 			goto out;
394 		NFSLOCKNODE(np);
395 		np->n_mtime = vattr.va_mtime;
396 		NFSUNLOCKNODE(np);
397 	} else {
398 		NFSUNLOCKNODE(np);
399 		error = VOP_GETATTR(vp, &vattr, cred);
400 		if (error)
401 			goto out;
402 		NFSLOCKNODE(np);
403 		if ((np->n_flag & NSIZECHANGED)
404 		    || (NFS_TIMESPEC_COMPARE(&np->n_mtime, &vattr.va_mtime))) {
405 			NFSUNLOCKNODE(np);
406 			if (vp->v_type == VDIR)
407 				ncl_invaldir(vp);
408 			error = ncl_vinvalbuf(vp, V_SAVE | V_ALLOWCLEAN, td, 1);
409 			if (error != 0)
410 				goto out;
411 			NFSLOCKNODE(np);
412 			np->n_mtime = vattr.va_mtime;
413 			np->n_flag &= ~NSIZECHANGED;
414 		}
415 		NFSUNLOCKNODE(np);
416 	}
417 out:
418 	ncl_excl_finish(vp, old_lock);
419 	return (error);
420 }
421 
422 /*
423  * Vnode op for read using bio
424  */
425 int
426 ncl_bioread(struct vnode *vp, struct uio *uio, int ioflag, struct ucred *cred)
427 {
428 	struct nfsnode *np = VTONFS(vp);
429 	struct buf *bp, *rabp;
430 	struct thread *td;
431 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
432 	daddr_t lbn, rabn;
433 	int biosize, bcount, error, i, n, nra, on, save2, seqcount;
434 	off_t tmp_off;
435 
436 	KASSERT(uio->uio_rw == UIO_READ, ("ncl_read mode"));
437 	if (uio->uio_resid == 0)
438 		return (0);
439 	if (uio->uio_offset < 0)	/* XXX VDIR cookies can be negative */
440 		return (EINVAL);
441 	td = uio->uio_td;
442 
443 	mtx_lock(&nmp->nm_mtx);
444 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
445 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
446 		mtx_unlock(&nmp->nm_mtx);
447 		(void)ncl_fsinfo(nmp, vp, cred, td);
448 		mtx_lock(&nmp->nm_mtx);
449 	}
450 	if (nmp->nm_rsize == 0 || nmp->nm_readdirsize == 0)
451 		(void) newnfs_iosize(nmp);
452 
453 	tmp_off = uio->uio_offset + uio->uio_resid;
454 	if (vp->v_type != VDIR &&
455 	    (tmp_off > nmp->nm_maxfilesize || tmp_off < uio->uio_offset)) {
456 		mtx_unlock(&nmp->nm_mtx);
457 		return (EFBIG);
458 	}
459 	mtx_unlock(&nmp->nm_mtx);
460 
461 	if (newnfs_directio_enable && (ioflag & IO_DIRECT) && (vp->v_type == VREG))
462 		/* No caching/ no readaheads. Just read data into the user buffer */
463 		return ncl_readrpc(vp, uio, cred);
464 
465 	n = 0;
466 	on = 0;
467 	biosize = vp->v_bufobj.bo_bsize;
468 	seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
469 
470 	error = nfs_bioread_check_cons(vp, td, cred);
471 	if (error)
472 		return error;
473 
474 	save2 = curthread_pflags2_set(TDP2_SBPAGES);
475 	do {
476 	    u_quad_t nsize;
477 
478 	    NFSLOCKNODE(np);
479 	    nsize = np->n_size;
480 	    NFSUNLOCKNODE(np);
481 
482 	    switch (vp->v_type) {
483 	    case VREG:
484 		NFSINCRGLOBAL(nfsstatsv1.biocache_reads);
485 		lbn = uio->uio_offset / biosize;
486 		on = uio->uio_offset - (lbn * biosize);
487 
488 		/*
489 		 * Start the read ahead(s), as required.
490 		 */
491 		if (nmp->nm_readahead > 0) {
492 		    for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
493 			(off_t)(lbn + 1 + nra) * biosize < nsize; nra++) {
494 			rabn = lbn + 1 + nra;
495 			if (incore(&vp->v_bufobj, rabn) == NULL) {
496 			    rabp = nfs_getcacheblk(vp, rabn, biosize, td);
497 			    if (!rabp) {
498 				error = newnfs_sigintr(nmp, td);
499 				if (error == 0)
500 					error = EINTR;
501 				goto out;
502 			    }
503 			    if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
504 				rabp->b_flags |= B_ASYNC;
505 				rabp->b_iocmd = BIO_READ;
506 				vfs_busy_pages(rabp, 0);
507 				if (ncl_asyncio(nmp, rabp, cred, td)) {
508 				    rabp->b_flags |= B_INVAL;
509 				    rabp->b_ioflags |= BIO_ERROR;
510 				    vfs_unbusy_pages(rabp);
511 				    brelse(rabp);
512 				    break;
513 				}
514 			    } else {
515 				brelse(rabp);
516 			    }
517 			}
518 		    }
519 		}
520 
521 		/* Note that bcount is *not* DEV_BSIZE aligned. */
522 		bcount = biosize;
523 		if ((off_t)lbn * biosize >= nsize) {
524 			bcount = 0;
525 		} else if ((off_t)(lbn + 1) * biosize > nsize) {
526 			bcount = nsize - (off_t)lbn * biosize;
527 		}
528 		bp = nfs_getcacheblk(vp, lbn, bcount, td);
529 
530 		if (!bp) {
531 			error = newnfs_sigintr(nmp, td);
532 			if (error == 0)
533 				error = EINTR;
534 			goto out;
535 		}
536 
537 		/*
538 		 * If B_CACHE is not set, we must issue the read.  If this
539 		 * fails, we return an error.
540 		 */
541 
542 		if ((bp->b_flags & B_CACHE) == 0) {
543 		    bp->b_iocmd = BIO_READ;
544 		    vfs_busy_pages(bp, 0);
545 		    error = ncl_doio(vp, bp, cred, td, 0);
546 		    if (error) {
547 			brelse(bp);
548 			goto out;
549 		    }
550 		}
551 
552 		/*
553 		 * on is the offset into the current bp.  Figure out how many
554 		 * bytes we can copy out of the bp.  Note that bcount is
555 		 * NOT DEV_BSIZE aligned.
556 		 *
557 		 * Then figure out how many bytes we can copy into the uio.
558 		 */
559 
560 		n = 0;
561 		if (on < bcount)
562 			n = MIN((unsigned)(bcount - on), uio->uio_resid);
563 		break;
564 	    case VLNK:
565 		NFSINCRGLOBAL(nfsstatsv1.biocache_readlinks);
566 		bp = nfs_getcacheblk(vp, (daddr_t)0, NFS_MAXPATHLEN, td);
567 		if (!bp) {
568 			error = newnfs_sigintr(nmp, td);
569 			if (error == 0)
570 				error = EINTR;
571 			goto out;
572 		}
573 		if ((bp->b_flags & B_CACHE) == 0) {
574 		    bp->b_iocmd = BIO_READ;
575 		    vfs_busy_pages(bp, 0);
576 		    error = ncl_doio(vp, bp, cred, td, 0);
577 		    if (error) {
578 			bp->b_ioflags |= BIO_ERROR;
579 			brelse(bp);
580 			goto out;
581 		    }
582 		}
583 		n = MIN(uio->uio_resid, NFS_MAXPATHLEN - bp->b_resid);
584 		on = 0;
585 		break;
586 	    case VDIR:
587 		NFSINCRGLOBAL(nfsstatsv1.biocache_readdirs);
588 		NFSLOCKNODE(np);
589 		if (np->n_direofoffset
590 		    && uio->uio_offset >= np->n_direofoffset) {
591 			NFSUNLOCKNODE(np);
592 			error = 0;
593 			goto out;
594 		}
595 		NFSUNLOCKNODE(np);
596 		lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
597 		on = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
598 		bp = nfs_getcacheblk(vp, lbn, NFS_DIRBLKSIZ, td);
599 		if (!bp) {
600 			error = newnfs_sigintr(nmp, td);
601 			if (error == 0)
602 				error = EINTR;
603 			goto out;
604 		}
605 		if ((bp->b_flags & B_CACHE) == 0) {
606 		    bp->b_iocmd = BIO_READ;
607 		    vfs_busy_pages(bp, 0);
608 		    error = ncl_doio(vp, bp, cred, td, 0);
609 		    if (error) {
610 			    brelse(bp);
611 		    }
612 		    while (error == NFSERR_BAD_COOKIE) {
613 			ncl_invaldir(vp);
614 			error = ncl_vinvalbuf(vp, 0, td, 1);
615 
616 			/*
617 			 * Yuck! The directory has been modified on the
618 			 * server. The only way to get the block is by
619 			 * reading from the beginning to get all the
620 			 * offset cookies.
621 			 *
622 			 * Leave the last bp intact unless there is an error.
623 			 * Loop back up to the while if the error is another
624 			 * NFSERR_BAD_COOKIE (double yuch!).
625 			 */
626 			for (i = 0; i <= lbn && !error; i++) {
627 			    NFSLOCKNODE(np);
628 			    if (np->n_direofoffset
629 				&& (i * NFS_DIRBLKSIZ) >= np->n_direofoffset) {
630 				    NFSUNLOCKNODE(np);
631 				    error = 0;
632 				    goto out;
633 			    }
634 			    NFSUNLOCKNODE(np);
635 			    bp = nfs_getcacheblk(vp, i, NFS_DIRBLKSIZ, td);
636 			    if (!bp) {
637 				error = newnfs_sigintr(nmp, td);
638 				if (error == 0)
639 					error = EINTR;
640 				goto out;
641 			    }
642 			    if ((bp->b_flags & B_CACHE) == 0) {
643 				    bp->b_iocmd = BIO_READ;
644 				    vfs_busy_pages(bp, 0);
645 				    error = ncl_doio(vp, bp, cred, td, 0);
646 				    /*
647 				     * no error + B_INVAL == directory EOF,
648 				     * use the block.
649 				     */
650 				    if (error == 0 && (bp->b_flags & B_INVAL))
651 					    break;
652 			    }
653 			    /*
654 			     * An error will throw away the block and the
655 			     * for loop will break out.  If no error and this
656 			     * is not the block we want, we throw away the
657 			     * block and go for the next one via the for loop.
658 			     */
659 			    if (error || i < lbn)
660 				    brelse(bp);
661 			}
662 		    }
663 		    /*
664 		     * The above while is repeated if we hit another cookie
665 		     * error.  If we hit an error and it wasn't a cookie error,
666 		     * we give up.
667 		     */
668 		    if (error)
669 			    goto out;
670 		}
671 
672 		/*
673 		 * If not eof and read aheads are enabled, start one.
674 		 * (You need the current block first, so that you have the
675 		 *  directory offset cookie of the next block.)
676 		 */
677 		NFSLOCKNODE(np);
678 		if (nmp->nm_readahead > 0 &&
679 		    (bp->b_flags & B_INVAL) == 0 &&
680 		    (np->n_direofoffset == 0 ||
681 		    (lbn + 1) * NFS_DIRBLKSIZ < np->n_direofoffset) &&
682 		    incore(&vp->v_bufobj, lbn + 1) == NULL) {
683 			NFSUNLOCKNODE(np);
684 			rabp = nfs_getcacheblk(vp, lbn + 1, NFS_DIRBLKSIZ, td);
685 			if (rabp) {
686 			    if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
687 				rabp->b_flags |= B_ASYNC;
688 				rabp->b_iocmd = BIO_READ;
689 				vfs_busy_pages(rabp, 0);
690 				if (ncl_asyncio(nmp, rabp, cred, td)) {
691 				    rabp->b_flags |= B_INVAL;
692 				    rabp->b_ioflags |= BIO_ERROR;
693 				    vfs_unbusy_pages(rabp);
694 				    brelse(rabp);
695 				}
696 			    } else {
697 				brelse(rabp);
698 			    }
699 			}
700 			NFSLOCKNODE(np);
701 		}
702 		/*
703 		 * Unlike VREG files, whos buffer size ( bp->b_bcount ) is
704 		 * chopped for the EOF condition, we cannot tell how large
705 		 * NFS directories are going to be until we hit EOF.  So
706 		 * an NFS directory buffer is *not* chopped to its EOF.  Now,
707 		 * it just so happens that b_resid will effectively chop it
708 		 * to EOF.  *BUT* this information is lost if the buffer goes
709 		 * away and is reconstituted into a B_CACHE state ( due to
710 		 * being VMIO ) later.  So we keep track of the directory eof
711 		 * in np->n_direofoffset and chop it off as an extra step
712 		 * right here.
713 		 */
714 		n = lmin(uio->uio_resid, NFS_DIRBLKSIZ - bp->b_resid - on);
715 		if (np->n_direofoffset && n > np->n_direofoffset - uio->uio_offset)
716 			n = np->n_direofoffset - uio->uio_offset;
717 		NFSUNLOCKNODE(np);
718 		break;
719 	    default:
720 		printf(" ncl_bioread: type %x unexpected\n", vp->v_type);
721 		bp = NULL;
722 		break;
723 	    }
724 
725 	    if (n > 0) {
726 		    error = vn_io_fault_uiomove(bp->b_data + on, (int)n, uio);
727 	    }
728 	    if (vp->v_type == VLNK)
729 		n = 0;
730 	    if (bp != NULL)
731 		brelse(bp);
732 	} while (error == 0 && uio->uio_resid > 0 && n > 0);
733 out:
734 	curthread_pflags2_restore(save2);
735 	if ((curthread->td_pflags2 & TDP2_SBPAGES) == 0) {
736 		NFSLOCKNODE(np);
737 		ncl_pager_setsize(vp, NULL);
738 	}
739 	return (error);
740 }
741 
742 /*
743  * The NFS write path cannot handle iovecs with len > 1. So we need to
744  * break up iovecs accordingly (restricting them to wsize).
745  * For the SYNC case, we can do this with 1 copy (user buffer -> mbuf).
746  * For the ASYNC case, 2 copies are needed. The first a copy from the
747  * user buffer to a staging buffer and then a second copy from the staging
748  * buffer to mbufs. This can be optimized by copying from the user buffer
749  * directly into mbufs and passing the chain down, but that requires a
750  * fair amount of re-working of the relevant codepaths (and can be done
751  * later).
752  */
753 static int
754 nfs_directio_write(vp, uiop, cred, ioflag)
755 	struct vnode *vp;
756 	struct uio *uiop;
757 	struct ucred *cred;
758 	int ioflag;
759 {
760 	int error;
761 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
762 	struct thread *td = uiop->uio_td;
763 	int size;
764 	int wsize;
765 
766 	mtx_lock(&nmp->nm_mtx);
767 	wsize = nmp->nm_wsize;
768 	mtx_unlock(&nmp->nm_mtx);
769 	if (ioflag & IO_SYNC) {
770 		int iomode, must_commit;
771 		struct uio uio;
772 		struct iovec iov;
773 do_sync:
774 		while (uiop->uio_resid > 0) {
775 			size = MIN(uiop->uio_resid, wsize);
776 			size = MIN(uiop->uio_iov->iov_len, size);
777 			iov.iov_base = uiop->uio_iov->iov_base;
778 			iov.iov_len = size;
779 			uio.uio_iov = &iov;
780 			uio.uio_iovcnt = 1;
781 			uio.uio_offset = uiop->uio_offset;
782 			uio.uio_resid = size;
783 			uio.uio_segflg = UIO_USERSPACE;
784 			uio.uio_rw = UIO_WRITE;
785 			uio.uio_td = td;
786 			iomode = NFSWRITE_FILESYNC;
787 			/*
788 			 * When doing direct I/O we do not care if the
789 			 * server's write verifier has changed, but we
790 			 * do not want to update the verifier if it has
791 			 * changed, since that hides the change from
792 			 * writes being done through the buffer cache.
793 			 * By passing must_commit in set to two, the code
794 			 * in nfsrpc_writerpc() will not update the
795 			 * verifier on the mount point.
796 			 */
797 			must_commit = 2;
798 			error = ncl_writerpc(vp, &uio, cred, &iomode,
799 			    &must_commit, 0);
800 			KASSERT((must_commit == 2),
801 			    ("ncl_directio_write: Updated write verifier"));
802 			if (error)
803 				return (error);
804 			if (iomode != NFSWRITE_FILESYNC)
805 				printf("nfs_directio_write: Broken server "
806 				    "did not reply FILE_SYNC\n");
807 			uiop->uio_offset += size;
808 			uiop->uio_resid -= size;
809 			if (uiop->uio_iov->iov_len <= size) {
810 				uiop->uio_iovcnt--;
811 				uiop->uio_iov++;
812 			} else {
813 				uiop->uio_iov->iov_base =
814 					(char *)uiop->uio_iov->iov_base + size;
815 				uiop->uio_iov->iov_len -= size;
816 			}
817 		}
818 	} else {
819 		struct uio *t_uio;
820 		struct iovec *t_iov;
821 		struct buf *bp;
822 
823 		/*
824 		 * Break up the write into blocksize chunks and hand these
825 		 * over to nfsiod's for write back.
826 		 * Unfortunately, this incurs a copy of the data. Since
827 		 * the user could modify the buffer before the write is
828 		 * initiated.
829 		 *
830 		 * The obvious optimization here is that one of the 2 copies
831 		 * in the async write path can be eliminated by copying the
832 		 * data here directly into mbufs and passing the mbuf chain
833 		 * down. But that will require a fair amount of re-working
834 		 * of the code and can be done if there's enough interest
835 		 * in NFS directio access.
836 		 */
837 		while (uiop->uio_resid > 0) {
838 			size = MIN(uiop->uio_resid, wsize);
839 			size = MIN(uiop->uio_iov->iov_len, size);
840 			bp = uma_zalloc(ncl_pbuf_zone, M_WAITOK);
841 			t_uio = malloc(sizeof(struct uio), M_NFSDIRECTIO, M_WAITOK);
842 			t_iov = malloc(sizeof(struct iovec), M_NFSDIRECTIO, M_WAITOK);
843 			t_iov->iov_base = malloc(size, M_NFSDIRECTIO, M_WAITOK);
844 			t_iov->iov_len = size;
845 			t_uio->uio_iov = t_iov;
846 			t_uio->uio_iovcnt = 1;
847 			t_uio->uio_offset = uiop->uio_offset;
848 			t_uio->uio_resid = size;
849 			t_uio->uio_segflg = UIO_SYSSPACE;
850 			t_uio->uio_rw = UIO_WRITE;
851 			t_uio->uio_td = td;
852 			KASSERT(uiop->uio_segflg == UIO_USERSPACE ||
853 			    uiop->uio_segflg == UIO_SYSSPACE,
854 			    ("nfs_directio_write: Bad uio_segflg"));
855 			if (uiop->uio_segflg == UIO_USERSPACE) {
856 				error = copyin(uiop->uio_iov->iov_base,
857 				    t_iov->iov_base, size);
858 				if (error != 0)
859 					goto err_free;
860 			} else
861 				/*
862 				 * UIO_SYSSPACE may never happen, but handle
863 				 * it just in case it does.
864 				 */
865 				bcopy(uiop->uio_iov->iov_base, t_iov->iov_base,
866 				    size);
867 			bp->b_flags |= B_DIRECT;
868 			bp->b_iocmd = BIO_WRITE;
869 			if (cred != NOCRED) {
870 				crhold(cred);
871 				bp->b_wcred = cred;
872 			} else
873 				bp->b_wcred = NOCRED;
874 			bp->b_caller1 = (void *)t_uio;
875 			bp->b_vp = vp;
876 			error = ncl_asyncio(nmp, bp, NOCRED, td);
877 err_free:
878 			if (error) {
879 				free(t_iov->iov_base, M_NFSDIRECTIO);
880 				free(t_iov, M_NFSDIRECTIO);
881 				free(t_uio, M_NFSDIRECTIO);
882 				bp->b_vp = NULL;
883 				uma_zfree(ncl_pbuf_zone, bp);
884 				if (error == EINTR)
885 					return (error);
886 				goto do_sync;
887 			}
888 			uiop->uio_offset += size;
889 			uiop->uio_resid -= size;
890 			if (uiop->uio_iov->iov_len <= size) {
891 				uiop->uio_iovcnt--;
892 				uiop->uio_iov++;
893 			} else {
894 				uiop->uio_iov->iov_base =
895 					(char *)uiop->uio_iov->iov_base + size;
896 				uiop->uio_iov->iov_len -= size;
897 			}
898 		}
899 	}
900 	return (0);
901 }
902 
903 /*
904  * Vnode op for write using bio
905  */
906 int
907 ncl_write(struct vop_write_args *ap)
908 {
909 	int biosize;
910 	struct uio *uio = ap->a_uio;
911 	struct thread *td = uio->uio_td;
912 	struct vnode *vp = ap->a_vp;
913 	struct nfsnode *np = VTONFS(vp);
914 	struct ucred *cred = ap->a_cred;
915 	int ioflag = ap->a_ioflag;
916 	struct buf *bp;
917 	struct vattr vattr;
918 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
919 	daddr_t lbn;
920 	int bcount, noncontig_write, obcount;
921 	int bp_cached, n, on, error = 0, error1, save2, wouldcommit;
922 	size_t orig_resid, local_resid;
923 	off_t orig_size, tmp_off;
924 	struct timespec ts;
925 
926 	KASSERT(uio->uio_rw == UIO_WRITE, ("ncl_write mode"));
927 	KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
928 	    ("ncl_write proc"));
929 	if (vp->v_type != VREG)
930 		return (EIO);
931 	NFSLOCKNODE(np);
932 	if (np->n_flag & NWRITEERR) {
933 		np->n_flag &= ~NWRITEERR;
934 		NFSUNLOCKNODE(np);
935 		return (np->n_error);
936 	} else
937 		NFSUNLOCKNODE(np);
938 	mtx_lock(&nmp->nm_mtx);
939 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
940 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
941 		mtx_unlock(&nmp->nm_mtx);
942 		(void)ncl_fsinfo(nmp, vp, cred, td);
943 		mtx_lock(&nmp->nm_mtx);
944 	}
945 	if (nmp->nm_wsize == 0)
946 		(void) newnfs_iosize(nmp);
947 	mtx_unlock(&nmp->nm_mtx);
948 
949 	/*
950 	 * Synchronously flush pending buffers if we are in synchronous
951 	 * mode or if we are appending.
952 	 */
953 	if (ioflag & (IO_APPEND | IO_SYNC)) {
954 		NFSLOCKNODE(np);
955 		if (np->n_flag & NMODIFIED) {
956 			NFSUNLOCKNODE(np);
957 #ifdef notyet /* Needs matching nonblock semantics elsewhere, too. */
958 			/*
959 			 * Require non-blocking, synchronous writes to
960 			 * dirty files to inform the program it needs
961 			 * to fsync(2) explicitly.
962 			 */
963 			if (ioflag & IO_NDELAY)
964 				return (EAGAIN);
965 #endif
966 			np->n_attrstamp = 0;
967 			KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
968 			error = ncl_vinvalbuf(vp, V_SAVE | ((ioflag &
969 			    IO_VMIO) != 0 ? V_VMIO : 0), td, 1);
970 			if (error != 0)
971 				return (error);
972 		} else
973 			NFSUNLOCKNODE(np);
974 	}
975 
976 	orig_resid = uio->uio_resid;
977 	NFSLOCKNODE(np);
978 	orig_size = np->n_size;
979 	NFSUNLOCKNODE(np);
980 
981 	/*
982 	 * If IO_APPEND then load uio_offset.  We restart here if we cannot
983 	 * get the append lock.
984 	 */
985 	if (ioflag & IO_APPEND) {
986 		np->n_attrstamp = 0;
987 		KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
988 		error = VOP_GETATTR(vp, &vattr, cred);
989 		if (error)
990 			return (error);
991 		NFSLOCKNODE(np);
992 		uio->uio_offset = np->n_size;
993 		NFSUNLOCKNODE(np);
994 	}
995 
996 	if (uio->uio_offset < 0)
997 		return (EINVAL);
998 	tmp_off = uio->uio_offset + uio->uio_resid;
999 	if (tmp_off > nmp->nm_maxfilesize || tmp_off < uio->uio_offset)
1000 		return (EFBIG);
1001 	if (uio->uio_resid == 0)
1002 		return (0);
1003 
1004 	if (vp->v_type == VREG && ((newnfs_directio_enable && (ioflag &
1005 	    IO_DIRECT)) || (ioflag & IO_APPEND))) {
1006 		if ((ioflag & IO_APPEND) != 0)
1007 			ioflag |= IO_SYNC;
1008 		return nfs_directio_write(vp, uio, cred, ioflag);
1009 	}
1010 
1011 	/*
1012 	 * Maybe this should be above the vnode op call, but so long as
1013 	 * file servers have no limits, i don't think it matters
1014 	 */
1015 	if (vn_rlimit_fsize(vp, uio, td))
1016 		return (EFBIG);
1017 
1018 	save2 = curthread_pflags2_set(TDP2_SBPAGES);
1019 	biosize = vp->v_bufobj.bo_bsize;
1020 	/*
1021 	 * Find all of this file's B_NEEDCOMMIT buffers.  If our writes
1022 	 * would exceed the local maximum per-file write commit size when
1023 	 * combined with those, we must decide whether to flush,
1024 	 * go synchronous, or return error.  We don't bother checking
1025 	 * IO_UNIT -- we just make all writes atomic anyway, as there's
1026 	 * no point optimizing for something that really won't ever happen.
1027 	 */
1028 	wouldcommit = 0;
1029 	if (!(ioflag & IO_SYNC)) {
1030 		int nflag;
1031 
1032 		NFSLOCKNODE(np);
1033 		nflag = np->n_flag;
1034 		NFSUNLOCKNODE(np);
1035 		if (nflag & NMODIFIED) {
1036 			BO_LOCK(&vp->v_bufobj);
1037 			if (vp->v_bufobj.bo_dirty.bv_cnt != 0) {
1038 				TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd,
1039 				    b_bobufs) {
1040 					if (bp->b_flags & B_NEEDCOMMIT)
1041 						wouldcommit += bp->b_bcount;
1042 				}
1043 			}
1044 			BO_UNLOCK(&vp->v_bufobj);
1045 		}
1046 	}
1047 
1048 	do {
1049 		if (!(ioflag & IO_SYNC)) {
1050 			wouldcommit += biosize;
1051 			if (wouldcommit > nmp->nm_wcommitsize) {
1052 				np->n_attrstamp = 0;
1053 				KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
1054 				error = ncl_vinvalbuf(vp, V_SAVE | ((ioflag &
1055 				    IO_VMIO) != 0 ? V_VMIO : 0), td, 1);
1056 				if (error != 0)
1057 					goto out;
1058 				wouldcommit = biosize;
1059 			}
1060 		}
1061 
1062 		NFSINCRGLOBAL(nfsstatsv1.biocache_writes);
1063 		lbn = uio->uio_offset / biosize;
1064 		on = uio->uio_offset - (lbn * biosize);
1065 		n = MIN((unsigned)(biosize - on), uio->uio_resid);
1066 again:
1067 		/*
1068 		 * Handle direct append and file extension cases, calculate
1069 		 * unaligned buffer size.
1070 		 */
1071 		NFSLOCKNODE(np);
1072 		if ((np->n_flag & NHASBEENLOCKED) == 0 &&
1073 		    (nmp->nm_flag & NFSMNT_NONCONTIGWR) != 0)
1074 			noncontig_write = 1;
1075 		else
1076 			noncontig_write = 0;
1077 		if ((uio->uio_offset == np->n_size ||
1078 		    (noncontig_write != 0 &&
1079 		    lbn == (np->n_size / biosize) &&
1080 		    uio->uio_offset + n > np->n_size)) && n) {
1081 			NFSUNLOCKNODE(np);
1082 			/*
1083 			 * Get the buffer (in its pre-append state to maintain
1084 			 * B_CACHE if it was previously set).  Resize the
1085 			 * nfsnode after we have locked the buffer to prevent
1086 			 * readers from reading garbage.
1087 			 */
1088 			obcount = np->n_size - (lbn * biosize);
1089 			bp = nfs_getcacheblk(vp, lbn, obcount, td);
1090 
1091 			if (bp != NULL) {
1092 				long save;
1093 
1094 				NFSLOCKNODE(np);
1095 				np->n_size = uio->uio_offset + n;
1096 				np->n_flag |= NMODIFIED;
1097 				np->n_flag &= ~NVNSETSZSKIP;
1098 				vnode_pager_setsize(vp, np->n_size);
1099 				NFSUNLOCKNODE(np);
1100 
1101 				save = bp->b_flags & B_CACHE;
1102 				bcount = on + n;
1103 				allocbuf(bp, bcount);
1104 				bp->b_flags |= save;
1105 				if (noncontig_write != 0 && on > obcount)
1106 					vfs_bio_bzero_buf(bp, obcount, on -
1107 					    obcount);
1108 			}
1109 		} else {
1110 			/*
1111 			 * Obtain the locked cache block first, and then
1112 			 * adjust the file's size as appropriate.
1113 			 */
1114 			bcount = on + n;
1115 			if ((off_t)lbn * biosize + bcount < np->n_size) {
1116 				if ((off_t)(lbn + 1) * biosize < np->n_size)
1117 					bcount = biosize;
1118 				else
1119 					bcount = np->n_size - (off_t)lbn * biosize;
1120 			}
1121 			NFSUNLOCKNODE(np);
1122 			bp = nfs_getcacheblk(vp, lbn, bcount, td);
1123 			NFSLOCKNODE(np);
1124 			if (uio->uio_offset + n > np->n_size) {
1125 				np->n_size = uio->uio_offset + n;
1126 				np->n_flag |= NMODIFIED;
1127 				np->n_flag &= ~NVNSETSZSKIP;
1128 				vnode_pager_setsize(vp, np->n_size);
1129 			}
1130 			NFSUNLOCKNODE(np);
1131 		}
1132 
1133 		if (!bp) {
1134 			error = newnfs_sigintr(nmp, td);
1135 			if (!error)
1136 				error = EINTR;
1137 			break;
1138 		}
1139 
1140 		/*
1141 		 * Issue a READ if B_CACHE is not set.  In special-append
1142 		 * mode, B_CACHE is based on the buffer prior to the write
1143 		 * op and is typically set, avoiding the read.  If a read
1144 		 * is required in special append mode, the server will
1145 		 * probably send us a short-read since we extended the file
1146 		 * on our end, resulting in b_resid == 0 and, thusly,
1147 		 * B_CACHE getting set.
1148 		 *
1149 		 * We can also avoid issuing the read if the write covers
1150 		 * the entire buffer.  We have to make sure the buffer state
1151 		 * is reasonable in this case since we will not be initiating
1152 		 * I/O.  See the comments in kern/vfs_bio.c's getblk() for
1153 		 * more information.
1154 		 *
1155 		 * B_CACHE may also be set due to the buffer being cached
1156 		 * normally.
1157 		 */
1158 
1159 		bp_cached = 1;
1160 		if (on == 0 && n == bcount) {
1161 			if ((bp->b_flags & B_CACHE) == 0)
1162 				bp_cached = 0;
1163 			bp->b_flags |= B_CACHE;
1164 			bp->b_flags &= ~B_INVAL;
1165 			bp->b_ioflags &= ~BIO_ERROR;
1166 		}
1167 
1168 		if ((bp->b_flags & B_CACHE) == 0) {
1169 			bp->b_iocmd = BIO_READ;
1170 			vfs_busy_pages(bp, 0);
1171 			error = ncl_doio(vp, bp, cred, td, 0);
1172 			if (error) {
1173 				brelse(bp);
1174 				break;
1175 			}
1176 		}
1177 		if (bp->b_wcred == NOCRED)
1178 			bp->b_wcred = crhold(cred);
1179 		NFSLOCKNODE(np);
1180 		np->n_flag |= NMODIFIED;
1181 		NFSUNLOCKNODE(np);
1182 
1183 		/*
1184 		 * If dirtyend exceeds file size, chop it down.  This should
1185 		 * not normally occur but there is an append race where it
1186 		 * might occur XXX, so we log it.
1187 		 *
1188 		 * If the chopping creates a reverse-indexed or degenerate
1189 		 * situation with dirtyoff/end, we 0 both of them.
1190 		 */
1191 
1192 		if (bp->b_dirtyend > bcount) {
1193 			printf("NFS append race @%lx:%d\n",
1194 			    (long)bp->b_blkno * DEV_BSIZE,
1195 			    bp->b_dirtyend - bcount);
1196 			bp->b_dirtyend = bcount;
1197 		}
1198 
1199 		if (bp->b_dirtyoff >= bp->b_dirtyend)
1200 			bp->b_dirtyoff = bp->b_dirtyend = 0;
1201 
1202 		/*
1203 		 * If the new write will leave a contiguous dirty
1204 		 * area, just update the b_dirtyoff and b_dirtyend,
1205 		 * otherwise force a write rpc of the old dirty area.
1206 		 *
1207 		 * If there has been a file lock applied to this file
1208 		 * or vfs.nfs.old_noncontig_writing is set, do the following:
1209 		 * While it is possible to merge discontiguous writes due to
1210 		 * our having a B_CACHE buffer ( and thus valid read data
1211 		 * for the hole), we don't because it could lead to
1212 		 * significant cache coherency problems with multiple clients,
1213 		 * especially if locking is implemented later on.
1214 		 *
1215 		 * If vfs.nfs.old_noncontig_writing is not set and there has
1216 		 * not been file locking done on this file:
1217 		 * Relax coherency a bit for the sake of performance and
1218 		 * expand the current dirty region to contain the new
1219 		 * write even if it means we mark some non-dirty data as
1220 		 * dirty.
1221 		 */
1222 
1223 		if (noncontig_write == 0 && bp->b_dirtyend > 0 &&
1224 		    (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) {
1225 			if (bwrite(bp) == EINTR) {
1226 				error = EINTR;
1227 				break;
1228 			}
1229 			goto again;
1230 		}
1231 
1232 		local_resid = uio->uio_resid;
1233 		error = vn_io_fault_uiomove((char *)bp->b_data + on, n, uio);
1234 
1235 		if (error != 0 && !bp_cached) {
1236 			/*
1237 			 * This block has no other content then what
1238 			 * possibly was written by the faulty uiomove.
1239 			 * Release it, forgetting the data pages, to
1240 			 * prevent the leak of uninitialized data to
1241 			 * usermode.
1242 			 */
1243 			bp->b_ioflags |= BIO_ERROR;
1244 			brelse(bp);
1245 			uio->uio_offset -= local_resid - uio->uio_resid;
1246 			uio->uio_resid = local_resid;
1247 			break;
1248 		}
1249 
1250 		/*
1251 		 * Since this block is being modified, it must be written
1252 		 * again and not just committed.  Since write clustering does
1253 		 * not work for the stage 1 data write, only the stage 2
1254 		 * commit rpc, we have to clear B_CLUSTEROK as well.
1255 		 */
1256 		bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1257 
1258 		/*
1259 		 * Get the partial update on the progress made from
1260 		 * uiomove, if an error occurred.
1261 		 */
1262 		if (error != 0)
1263 			n = local_resid - uio->uio_resid;
1264 
1265 		/*
1266 		 * Only update dirtyoff/dirtyend if not a degenerate
1267 		 * condition.
1268 		 */
1269 		if (n > 0) {
1270 			if (bp->b_dirtyend > 0) {
1271 				bp->b_dirtyoff = min(on, bp->b_dirtyoff);
1272 				bp->b_dirtyend = max((on + n), bp->b_dirtyend);
1273 			} else {
1274 				bp->b_dirtyoff = on;
1275 				bp->b_dirtyend = on + n;
1276 			}
1277 			vfs_bio_set_valid(bp, on, n);
1278 		}
1279 
1280 		/*
1281 		 * If IO_SYNC do bwrite().
1282 		 *
1283 		 * IO_INVAL appears to be unused.  The idea appears to be
1284 		 * to turn off caching in this case.  Very odd.  XXX
1285 		 */
1286 		if ((ioflag & IO_SYNC)) {
1287 			if (ioflag & IO_INVAL)
1288 				bp->b_flags |= B_NOCACHE;
1289 			error1 = bwrite(bp);
1290 			if (error1 != 0) {
1291 				if (error == 0)
1292 					error = error1;
1293 				break;
1294 			}
1295 		} else if ((n + on) == biosize || (ioflag & IO_ASYNC) != 0) {
1296 			bp->b_flags |= B_ASYNC;
1297 			(void) ncl_writebp(bp, 0, NULL);
1298 		} else {
1299 			bdwrite(bp);
1300 		}
1301 
1302 		if (error != 0)
1303 			break;
1304 	} while (uio->uio_resid > 0 && n > 0);
1305 
1306 	if (error == 0) {
1307 		nanouptime(&ts);
1308 		NFSLOCKNODE(np);
1309 		np->n_localmodtime = ts;
1310 		NFSUNLOCKNODE(np);
1311 	} else {
1312 		if (ioflag & IO_UNIT) {
1313 			VATTR_NULL(&vattr);
1314 			vattr.va_size = orig_size;
1315 			/* IO_SYNC is handled implicitely */
1316 			(void)VOP_SETATTR(vp, &vattr, cred);
1317 			uio->uio_offset -= orig_resid - uio->uio_resid;
1318 			uio->uio_resid = orig_resid;
1319 		}
1320 	}
1321 
1322 out:
1323 	curthread_pflags2_restore(save2);
1324 	return (error);
1325 }
1326 
1327 /*
1328  * Get an nfs cache block.
1329  *
1330  * Allocate a new one if the block isn't currently in the cache
1331  * and return the block marked busy. If the calling process is
1332  * interrupted by a signal for an interruptible mount point, return
1333  * NULL.
1334  *
1335  * The caller must carefully deal with the possible B_INVAL state of
1336  * the buffer.  ncl_doio() clears B_INVAL (and ncl_asyncio() clears it
1337  * indirectly), so synchronous reads can be issued without worrying about
1338  * the B_INVAL state.  We have to be a little more careful when dealing
1339  * with writes (see comments in nfs_write()) when extending a file past
1340  * its EOF.
1341  */
1342 static struct buf *
1343 nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size, struct thread *td)
1344 {
1345 	struct buf *bp;
1346 	struct mount *mp;
1347 	struct nfsmount *nmp;
1348 
1349 	mp = vp->v_mount;
1350 	nmp = VFSTONFS(mp);
1351 
1352 	if (nmp->nm_flag & NFSMNT_INT) {
1353 		sigset_t oldset;
1354 
1355 		newnfs_set_sigmask(td, &oldset);
1356 		bp = getblk(vp, bn, size, PCATCH, 0, 0);
1357 		newnfs_restore_sigmask(td, &oldset);
1358 		while (bp == NULL) {
1359 			if (newnfs_sigintr(nmp, td))
1360 				return (NULL);
1361 			bp = getblk(vp, bn, size, 0, 2 * hz, 0);
1362 		}
1363 	} else {
1364 		bp = getblk(vp, bn, size, 0, 0, 0);
1365 	}
1366 
1367 	if (vp->v_type == VREG)
1368 		bp->b_blkno = bn * (vp->v_bufobj.bo_bsize / DEV_BSIZE);
1369 	return (bp);
1370 }
1371 
1372 /*
1373  * Flush and invalidate all dirty buffers. If another process is already
1374  * doing the flush, just wait for completion.
1375  */
1376 int
1377 ncl_vinvalbuf(struct vnode *vp, int flags, struct thread *td, int intrflg)
1378 {
1379 	struct nfsnode *np = VTONFS(vp);
1380 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
1381 	int error = 0, slpflag, slptimeo;
1382 	bool old_lock;
1383 	struct timespec ts;
1384 
1385 	ASSERT_VOP_LOCKED(vp, "ncl_vinvalbuf");
1386 
1387 	if ((nmp->nm_flag & NFSMNT_INT) == 0)
1388 		intrflg = 0;
1389 	if (NFSCL_FORCEDISM(nmp->nm_mountp))
1390 		intrflg = 1;
1391 	if (intrflg) {
1392 		slpflag = PCATCH;
1393 		slptimeo = 2 * hz;
1394 	} else {
1395 		slpflag = 0;
1396 		slptimeo = 0;
1397 	}
1398 
1399 	old_lock = ncl_excl_start(vp);
1400 	if (old_lock)
1401 		flags |= V_ALLOWCLEAN;
1402 
1403 	/*
1404 	 * Now, flush as required.
1405 	 */
1406 	if ((flags & (V_SAVE | V_VMIO)) == V_SAVE &&
1407 	     vp->v_bufobj.bo_object != NULL) {
1408 		VM_OBJECT_WLOCK(vp->v_bufobj.bo_object);
1409 		vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC);
1410 		VM_OBJECT_WUNLOCK(vp->v_bufobj.bo_object);
1411 		/*
1412 		 * If the page clean was interrupted, fail the invalidation.
1413 		 * Not doing so, we run the risk of losing dirty pages in the
1414 		 * vinvalbuf() call below.
1415 		 */
1416 		if (intrflg && (error = newnfs_sigintr(nmp, td)))
1417 			goto out;
1418 	}
1419 
1420 	error = vinvalbuf(vp, flags, slpflag, 0);
1421 	while (error) {
1422 		if (intrflg && (error = newnfs_sigintr(nmp, td)))
1423 			goto out;
1424 		error = vinvalbuf(vp, flags, 0, slptimeo);
1425 	}
1426 	if (NFSHASPNFS(nmp)) {
1427 		nfscl_layoutcommit(vp, td);
1428 		nanouptime(&ts);
1429 		/*
1430 		 * Invalidate the attribute cache, since writes to a DS
1431 		 * won't update the size attribute.
1432 		 */
1433 		NFSLOCKNODE(np);
1434 		np->n_attrstamp = 0;
1435 	} else {
1436 		nanouptime(&ts);
1437 		NFSLOCKNODE(np);
1438 	}
1439 	if (np->n_directio_asyncwr == 0 && (np->n_flag & NMODIFIED) != 0) {
1440 		np->n_localmodtime = ts;
1441 		np->n_flag &= ~NMODIFIED;
1442 	}
1443 	NFSUNLOCKNODE(np);
1444 out:
1445 	ncl_excl_finish(vp, old_lock);
1446 	return error;
1447 }
1448 
1449 /*
1450  * Initiate asynchronous I/O. Return an error if no nfsiods are available.
1451  * This is mainly to avoid queueing async I/O requests when the nfsiods
1452  * are all hung on a dead server.
1453  *
1454  * Note: ncl_asyncio() does not clear (BIO_ERROR|B_INVAL) but when the bp
1455  * is eventually dequeued by the async daemon, ncl_doio() *will*.
1456  */
1457 int
1458 ncl_asyncio(struct nfsmount *nmp, struct buf *bp, struct ucred *cred, struct thread *td)
1459 {
1460 	int iod;
1461 	int gotiod;
1462 	int slpflag = 0;
1463 	int slptimeo = 0;
1464 	int error, error2;
1465 
1466 	/*
1467 	 * Commits are usually short and sweet so lets save some cpu and
1468 	 * leave the async daemons for more important rpc's (such as reads
1469 	 * and writes).
1470 	 *
1471 	 * Readdirplus RPCs do vget()s to acquire the vnodes for entries
1472 	 * in the directory in order to update attributes. This can deadlock
1473 	 * with another thread that is waiting for async I/O to be done by
1474 	 * an nfsiod thread while holding a lock on one of these vnodes.
1475 	 * To avoid this deadlock, don't allow the async nfsiod threads to
1476 	 * perform Readdirplus RPCs.
1477 	 */
1478 	NFSLOCKIOD();
1479 	if ((bp->b_iocmd == BIO_WRITE && (bp->b_flags & B_NEEDCOMMIT) &&
1480 	     (nmp->nm_bufqiods > ncl_numasync / 2)) ||
1481 	    (bp->b_vp->v_type == VDIR && (nmp->nm_flag & NFSMNT_RDIRPLUS))) {
1482 		NFSUNLOCKIOD();
1483 		return(EIO);
1484 	}
1485 again:
1486 	if (nmp->nm_flag & NFSMNT_INT)
1487 		slpflag = PCATCH;
1488 	gotiod = FALSE;
1489 
1490 	/*
1491 	 * Find a free iod to process this request.
1492 	 */
1493 	for (iod = 0; iod < ncl_numasync; iod++)
1494 		if (ncl_iodwant[iod] == NFSIOD_AVAILABLE) {
1495 			gotiod = TRUE;
1496 			break;
1497 		}
1498 
1499 	/*
1500 	 * Try to create one if none are free.
1501 	 */
1502 	if (!gotiod)
1503 		ncl_nfsiodnew();
1504 	else {
1505 		/*
1506 		 * Found one, so wake it up and tell it which
1507 		 * mount to process.
1508 		 */
1509 		NFS_DPF(ASYNCIO, ("ncl_asyncio: waking iod %d for mount %p\n",
1510 		    iod, nmp));
1511 		ncl_iodwant[iod] = NFSIOD_NOT_AVAILABLE;
1512 		ncl_iodmount[iod] = nmp;
1513 		nmp->nm_bufqiods++;
1514 		wakeup(&ncl_iodwant[iod]);
1515 	}
1516 
1517 	/*
1518 	 * If none are free, we may already have an iod working on this mount
1519 	 * point.  If so, it will process our request.
1520 	 */
1521 	if (!gotiod) {
1522 		if (nmp->nm_bufqiods > 0) {
1523 			NFS_DPF(ASYNCIO,
1524 				("ncl_asyncio: %d iods are already processing mount %p\n",
1525 				 nmp->nm_bufqiods, nmp));
1526 			gotiod = TRUE;
1527 		}
1528 	}
1529 
1530 	/*
1531 	 * If we have an iod which can process the request, then queue
1532 	 * the buffer.
1533 	 */
1534 	if (gotiod) {
1535 		/*
1536 		 * Ensure that the queue never grows too large.  We still want
1537 		 * to asynchronize so we block rather then return EIO.
1538 		 */
1539 		while (nmp->nm_bufqlen >= 2*ncl_numasync) {
1540 			NFS_DPF(ASYNCIO,
1541 				("ncl_asyncio: waiting for mount %p queue to drain\n", nmp));
1542 			nmp->nm_bufqwant = TRUE;
1543 			error = newnfs_msleep(td, &nmp->nm_bufq,
1544 			    &ncl_iod_mutex, slpflag | PRIBIO, "nfsaio",
1545 			   slptimeo);
1546 			if (error) {
1547 				error2 = newnfs_sigintr(nmp, td);
1548 				if (error2) {
1549 					NFSUNLOCKIOD();
1550 					return (error2);
1551 				}
1552 				if (slpflag == PCATCH) {
1553 					slpflag = 0;
1554 					slptimeo = 2 * hz;
1555 				}
1556 			}
1557 			/*
1558 			 * We might have lost our iod while sleeping,
1559 			 * so check and loop if necessary.
1560 			 */
1561 			goto again;
1562 		}
1563 
1564 		/* We might have lost our nfsiod */
1565 		if (nmp->nm_bufqiods == 0) {
1566 			NFS_DPF(ASYNCIO,
1567 				("ncl_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
1568 			goto again;
1569 		}
1570 
1571 		if (bp->b_iocmd == BIO_READ) {
1572 			if (bp->b_rcred == NOCRED && cred != NOCRED)
1573 				bp->b_rcred = crhold(cred);
1574 		} else {
1575 			if (bp->b_wcred == NOCRED && cred != NOCRED)
1576 				bp->b_wcred = crhold(cred);
1577 		}
1578 
1579 		if (bp->b_flags & B_REMFREE)
1580 			bremfreef(bp);
1581 		BUF_KERNPROC(bp);
1582 		TAILQ_INSERT_TAIL(&nmp->nm_bufq, bp, b_freelist);
1583 		nmp->nm_bufqlen++;
1584 		if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
1585 			NFSLOCKNODE(VTONFS(bp->b_vp));
1586 			VTONFS(bp->b_vp)->n_flag |= NMODIFIED;
1587 			VTONFS(bp->b_vp)->n_directio_asyncwr++;
1588 			NFSUNLOCKNODE(VTONFS(bp->b_vp));
1589 		}
1590 		NFSUNLOCKIOD();
1591 		return (0);
1592 	}
1593 
1594 	NFSUNLOCKIOD();
1595 
1596 	/*
1597 	 * All the iods are busy on other mounts, so return EIO to
1598 	 * force the caller to process the i/o synchronously.
1599 	 */
1600 	NFS_DPF(ASYNCIO, ("ncl_asyncio: no iods available, i/o is synchronous\n"));
1601 	return (EIO);
1602 }
1603 
1604 void
1605 ncl_doio_directwrite(struct buf *bp)
1606 {
1607 	int iomode, must_commit;
1608 	struct uio *uiop = (struct uio *)bp->b_caller1;
1609 	char *iov_base = uiop->uio_iov->iov_base;
1610 
1611 	iomode = NFSWRITE_FILESYNC;
1612 	uiop->uio_td = NULL; /* NULL since we're in nfsiod */
1613 	/*
1614 	 * When doing direct I/O we do not care if the
1615 	 * server's write verifier has changed, but we
1616 	 * do not want to update the verifier if it has
1617 	 * changed, since that hides the change from
1618 	 * writes being done through the buffer cache.
1619 	 * By passing must_commit in set to two, the code
1620 	 * in nfsrpc_writerpc() will not update the
1621 	 * verifier on the mount point.
1622 	 */
1623 	must_commit = 2;
1624 	ncl_writerpc(bp->b_vp, uiop, bp->b_wcred, &iomode, &must_commit, 0);
1625 	KASSERT((must_commit == 2), ("ncl_doio_directwrite: Updated write"
1626 	    " verifier"));
1627 	if (iomode != NFSWRITE_FILESYNC)
1628 		printf("ncl_doio_directwrite: Broken server "
1629 		    "did not reply FILE_SYNC\n");
1630 	free(iov_base, M_NFSDIRECTIO);
1631 	free(uiop->uio_iov, M_NFSDIRECTIO);
1632 	free(uiop, M_NFSDIRECTIO);
1633 	if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
1634 		struct nfsnode *np = VTONFS(bp->b_vp);
1635 		NFSLOCKNODE(np);
1636 		if (NFSHASPNFS(VFSTONFS(bp->b_vp->v_mount))) {
1637 			/*
1638 			 * Invalidate the attribute cache, since writes to a DS
1639 			 * won't update the size attribute.
1640 			 */
1641 			np->n_attrstamp = 0;
1642 		}
1643 		np->n_directio_asyncwr--;
1644 		if (np->n_directio_asyncwr == 0) {
1645 			np->n_flag &= ~NMODIFIED;
1646 			if ((np->n_flag & NFSYNCWAIT)) {
1647 				np->n_flag &= ~NFSYNCWAIT;
1648 				wakeup((caddr_t)&np->n_directio_asyncwr);
1649 			}
1650 		}
1651 		NFSUNLOCKNODE(np);
1652 	}
1653 	bp->b_vp = NULL;
1654 	uma_zfree(ncl_pbuf_zone, bp);
1655 }
1656 
1657 /*
1658  * Do an I/O operation to/from a cache block. This may be called
1659  * synchronously or from an nfsiod.
1660  */
1661 int
1662 ncl_doio(struct vnode *vp, struct buf *bp, struct ucred *cr, struct thread *td,
1663     int called_from_strategy)
1664 {
1665 	struct uio *uiop;
1666 	struct nfsnode *np;
1667 	struct nfsmount *nmp;
1668 	int error = 0, iomode, must_commit = 0;
1669 	struct uio uio;
1670 	struct iovec io;
1671 	struct proc *p = td ? td->td_proc : NULL;
1672 	uint8_t	iocmd;
1673 
1674 	np = VTONFS(vp);
1675 	nmp = VFSTONFS(vp->v_mount);
1676 	uiop = &uio;
1677 	uiop->uio_iov = &io;
1678 	uiop->uio_iovcnt = 1;
1679 	uiop->uio_segflg = UIO_SYSSPACE;
1680 	uiop->uio_td = td;
1681 
1682 	/*
1683 	 * clear BIO_ERROR and B_INVAL state prior to initiating the I/O.  We
1684 	 * do this here so we do not have to do it in all the code that
1685 	 * calls us.
1686 	 */
1687 	bp->b_flags &= ~B_INVAL;
1688 	bp->b_ioflags &= ~BIO_ERROR;
1689 
1690 	KASSERT(!(bp->b_flags & B_DONE), ("ncl_doio: bp %p already marked done", bp));
1691 	iocmd = bp->b_iocmd;
1692 	if (iocmd == BIO_READ) {
1693 	    io.iov_len = uiop->uio_resid = bp->b_bcount;
1694 	    io.iov_base = bp->b_data;
1695 	    uiop->uio_rw = UIO_READ;
1696 
1697 	    switch (vp->v_type) {
1698 	    case VREG:
1699 		uiop->uio_offset = ((off_t)bp->b_blkno) * DEV_BSIZE;
1700 		NFSINCRGLOBAL(nfsstatsv1.read_bios);
1701 		error = ncl_readrpc(vp, uiop, cr);
1702 
1703 		if (!error) {
1704 		    if (uiop->uio_resid) {
1705 			/*
1706 			 * If we had a short read with no error, we must have
1707 			 * hit a file hole.  We should zero-fill the remainder.
1708 			 * This can also occur if the server hits the file EOF.
1709 			 *
1710 			 * Holes used to be able to occur due to pending
1711 			 * writes, but that is not possible any longer.
1712 			 */
1713 			int nread = bp->b_bcount - uiop->uio_resid;
1714 			ssize_t left = uiop->uio_resid;
1715 
1716 			if (left > 0)
1717 				bzero((char *)bp->b_data + nread, left);
1718 			uiop->uio_resid = 0;
1719 		    }
1720 		}
1721 		/* ASSERT_VOP_LOCKED(vp, "ncl_doio"); */
1722 		if (p && vp->v_writecount <= -1) {
1723 			NFSLOCKNODE(np);
1724 			if (NFS_TIMESPEC_COMPARE(&np->n_mtime, &np->n_vattr.na_mtime)) {
1725 				NFSUNLOCKNODE(np);
1726 				PROC_LOCK(p);
1727 				killproc(p, "text file modification");
1728 				PROC_UNLOCK(p);
1729 			} else
1730 				NFSUNLOCKNODE(np);
1731 		}
1732 		break;
1733 	    case VLNK:
1734 		uiop->uio_offset = (off_t)0;
1735 		NFSINCRGLOBAL(nfsstatsv1.readlink_bios);
1736 		error = ncl_readlinkrpc(vp, uiop, cr);
1737 		break;
1738 	    case VDIR:
1739 		NFSINCRGLOBAL(nfsstatsv1.readdir_bios);
1740 		uiop->uio_offset = ((u_quad_t)bp->b_lblkno) * NFS_DIRBLKSIZ;
1741 		if ((nmp->nm_flag & NFSMNT_RDIRPLUS) != 0) {
1742 			error = ncl_readdirplusrpc(vp, uiop, cr, td);
1743 			if (error == NFSERR_NOTSUPP)
1744 				nmp->nm_flag &= ~NFSMNT_RDIRPLUS;
1745 		}
1746 		if ((nmp->nm_flag & NFSMNT_RDIRPLUS) == 0)
1747 			error = ncl_readdirrpc(vp, uiop, cr, td);
1748 		/*
1749 		 * end-of-directory sets B_INVAL but does not generate an
1750 		 * error.
1751 		 */
1752 		if (error == 0 && uiop->uio_resid == bp->b_bcount)
1753 			bp->b_flags |= B_INVAL;
1754 		break;
1755 	    default:
1756 		printf("ncl_doio:  type %x unexpected\n", vp->v_type);
1757 		break;
1758 	    }
1759 	    if (error) {
1760 		bp->b_ioflags |= BIO_ERROR;
1761 		bp->b_error = error;
1762 	    }
1763 	} else {
1764 	    /*
1765 	     * If we only need to commit, try to commit
1766 	     */
1767 	    if (bp->b_flags & B_NEEDCOMMIT) {
1768 		    int retv;
1769 		    off_t off;
1770 
1771 		    off = ((u_quad_t)bp->b_blkno) * DEV_BSIZE + bp->b_dirtyoff;
1772 		    retv = ncl_commit(vp, off, bp->b_dirtyend-bp->b_dirtyoff,
1773 			bp->b_wcred, td);
1774 		    if (NFSCL_FORCEDISM(vp->v_mount) || retv == 0) {
1775 			    bp->b_dirtyoff = bp->b_dirtyend = 0;
1776 			    bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1777 			    bp->b_resid = 0;
1778 			    bufdone(bp);
1779 			    return (0);
1780 		    }
1781 		    if (retv == NFSERR_STALEWRITEVERF) {
1782 			    ncl_clearcommit(vp->v_mount);
1783 		    }
1784 	    }
1785 
1786 	    /*
1787 	     * Setup for actual write
1788 	     */
1789 	    NFSLOCKNODE(np);
1790 	    if ((off_t)bp->b_blkno * DEV_BSIZE + bp->b_dirtyend > np->n_size)
1791 		bp->b_dirtyend = np->n_size - (off_t)bp->b_blkno * DEV_BSIZE;
1792 	    NFSUNLOCKNODE(np);
1793 
1794 	    if (bp->b_dirtyend > bp->b_dirtyoff) {
1795 		io.iov_len = uiop->uio_resid = bp->b_dirtyend
1796 		    - bp->b_dirtyoff;
1797 		uiop->uio_offset = (off_t)bp->b_blkno * DEV_BSIZE
1798 		    + bp->b_dirtyoff;
1799 		io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
1800 		uiop->uio_rw = UIO_WRITE;
1801 		NFSINCRGLOBAL(nfsstatsv1.write_bios);
1802 
1803 		if ((bp->b_flags & (B_ASYNC | B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == B_ASYNC)
1804 		    iomode = NFSWRITE_UNSTABLE;
1805 		else
1806 		    iomode = NFSWRITE_FILESYNC;
1807 
1808 		error = ncl_writerpc(vp, uiop, cr, &iomode, &must_commit,
1809 		    called_from_strategy);
1810 
1811 		/*
1812 		 * When setting B_NEEDCOMMIT also set B_CLUSTEROK to try
1813 		 * to cluster the buffers needing commit.  This will allow
1814 		 * the system to submit a single commit rpc for the whole
1815 		 * cluster.  We can do this even if the buffer is not 100%
1816 		 * dirty (relative to the NFS blocksize), so we optimize the
1817 		 * append-to-file-case.
1818 		 *
1819 		 * (when clearing B_NEEDCOMMIT, B_CLUSTEROK must also be
1820 		 * cleared because write clustering only works for commit
1821 		 * rpc's, not for the data portion of the write).
1822 		 */
1823 
1824 		if (!error && iomode == NFSWRITE_UNSTABLE) {
1825 		    bp->b_flags |= B_NEEDCOMMIT;
1826 		    if (bp->b_dirtyoff == 0
1827 			&& bp->b_dirtyend == bp->b_bcount)
1828 			bp->b_flags |= B_CLUSTEROK;
1829 		} else {
1830 		    bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1831 		}
1832 
1833 		/*
1834 		 * For an interrupted write, the buffer is still valid
1835 		 * and the write hasn't been pushed to the server yet,
1836 		 * so we can't set BIO_ERROR and report the interruption
1837 		 * by setting B_EINTR. For the B_ASYNC case, B_EINTR
1838 		 * is not relevant, so the rpc attempt is essentially
1839 		 * a noop.  For the case of a V3 write rpc not being
1840 		 * committed to stable storage, the block is still
1841 		 * dirty and requires either a commit rpc or another
1842 		 * write rpc with iomode == NFSV3WRITE_FILESYNC before
1843 		 * the block is reused. This is indicated by setting
1844 		 * the B_DELWRI and B_NEEDCOMMIT flags.
1845 		 *
1846 		 * EIO is returned by ncl_writerpc() to indicate a recoverable
1847 		 * write error and is handled as above, except that
1848 		 * B_EINTR isn't set. One cause of this is a stale stateid
1849 		 * error for the RPC that indicates recovery is required,
1850 		 * when called with called_from_strategy != 0.
1851 		 *
1852 		 * If the buffer is marked B_PAGING, it does not reside on
1853 		 * the vp's paging queues so we cannot call bdirty().  The
1854 		 * bp in this case is not an NFS cache block so we should
1855 		 * be safe. XXX
1856 		 *
1857 		 * The logic below breaks up errors into recoverable and
1858 		 * unrecoverable. For the former, we clear B_INVAL|B_NOCACHE
1859 		 * and keep the buffer around for potential write retries.
1860 		 * For the latter (eg ESTALE), we toss the buffer away (B_INVAL)
1861 		 * and save the error in the nfsnode. This is less than ideal
1862 		 * but necessary. Keeping such buffers around could potentially
1863 		 * cause buffer exhaustion eventually (they can never be written
1864 		 * out, so will get constantly be re-dirtied). It also causes
1865 		 * all sorts of vfs panics. For non-recoverable write errors,
1866 		 * also invalidate the attrcache, so we'll be forced to go over
1867 		 * the wire for this object, returning an error to user on next
1868 		 * call (most of the time).
1869 		 */
1870 		if (error == EINTR || error == EIO || error == ETIMEDOUT
1871 		    || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
1872 			bp->b_flags &= ~(B_INVAL|B_NOCACHE);
1873 			if ((bp->b_flags & B_PAGING) == 0) {
1874 			    bdirty(bp);
1875 			    bp->b_flags &= ~B_DONE;
1876 			}
1877 			if ((error == EINTR || error == ETIMEDOUT) &&
1878 			    (bp->b_flags & B_ASYNC) == 0)
1879 			    bp->b_flags |= B_EINTR;
1880 		} else {
1881 		    if (error) {
1882 			bp->b_ioflags |= BIO_ERROR;
1883 			bp->b_flags |= B_INVAL;
1884 			bp->b_error = np->n_error = error;
1885 			NFSLOCKNODE(np);
1886 			np->n_flag |= NWRITEERR;
1887 			np->n_attrstamp = 0;
1888 			KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
1889 			NFSUNLOCKNODE(np);
1890 		    }
1891 		    bp->b_dirtyoff = bp->b_dirtyend = 0;
1892 		}
1893 	    } else {
1894 		bp->b_resid = 0;
1895 		bufdone(bp);
1896 		return (0);
1897 	    }
1898 	}
1899 	bp->b_resid = uiop->uio_resid;
1900 	if (must_commit == 1)
1901 	    ncl_clearcommit(vp->v_mount);
1902 	bufdone(bp);
1903 	return (error);
1904 }
1905 
1906 /*
1907  * Used to aid in handling ftruncate() operations on the NFS client side.
1908  * Truncation creates a number of special problems for NFS.  We have to
1909  * throw away VM pages and buffer cache buffers that are beyond EOF, and
1910  * we have to properly handle VM pages or (potentially dirty) buffers
1911  * that straddle the truncation point.
1912  */
1913 
1914 int
1915 ncl_meta_setsize(struct vnode *vp, struct thread *td, u_quad_t nsize)
1916 {
1917 	struct nfsnode *np = VTONFS(vp);
1918 	u_quad_t tsize;
1919 	int biosize = vp->v_bufobj.bo_bsize;
1920 	int error = 0;
1921 
1922 	NFSLOCKNODE(np);
1923 	tsize = np->n_size;
1924 	np->n_size = nsize;
1925 	NFSUNLOCKNODE(np);
1926 
1927 	if (nsize < tsize) {
1928 		struct buf *bp;
1929 		daddr_t lbn;
1930 		int bufsize;
1931 
1932 		/*
1933 		 * vtruncbuf() doesn't get the buffer overlapping the
1934 		 * truncation point.  We may have a B_DELWRI and/or B_CACHE
1935 		 * buffer that now needs to be truncated.
1936 		 */
1937 		error = vtruncbuf(vp, nsize, biosize);
1938 		lbn = nsize / biosize;
1939 		bufsize = nsize - (lbn * biosize);
1940 		bp = nfs_getcacheblk(vp, lbn, bufsize, td);
1941 		if (!bp)
1942 			return EINTR;
1943 		if (bp->b_dirtyoff > bp->b_bcount)
1944 			bp->b_dirtyoff = bp->b_bcount;
1945 		if (bp->b_dirtyend > bp->b_bcount)
1946 			bp->b_dirtyend = bp->b_bcount;
1947 		bp->b_flags |= B_RELBUF;  /* don't leave garbage around */
1948 		brelse(bp);
1949 	} else {
1950 		vnode_pager_setsize(vp, nsize);
1951 	}
1952 	return(error);
1953 }
1954