xref: /dflybsd-src/sys/vfs/nfs/nfs_bio.c (revision c3c96e4421a1087a390825eac6c01c9ed9182387)
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  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	@(#)nfs_bio.c	8.9 (Berkeley) 3/30/95
37  * $FreeBSD: /repoman/r/ncvs/src/sys/nfsclient/nfs_bio.c,v 1.130 2004/04/14 23:23:55 peadar Exp $
38  * $DragonFly: src/sys/vfs/nfs/nfs_bio.c,v 1.45 2008/07/18 00:09:39 dillon Exp $
39  */
40 
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/resourcevar.h>
45 #include <sys/signalvar.h>
46 #include <sys/proc.h>
47 #include <sys/buf.h>
48 #include <sys/vnode.h>
49 #include <sys/mount.h>
50 #include <sys/kernel.h>
51 #include <sys/mbuf.h>
52 
53 #include <vm/vm.h>
54 #include <vm/vm_extern.h>
55 #include <vm/vm_page.h>
56 #include <vm/vm_object.h>
57 #include <vm/vm_pager.h>
58 #include <vm/vnode_pager.h>
59 
60 #include <sys/buf2.h>
61 #include <sys/thread2.h>
62 #include <sys/mplock2.h>
63 #include <vm/vm_page2.h>
64 
65 #include "rpcv2.h"
66 #include "nfsproto.h"
67 #include "nfs.h"
68 #include "nfsmount.h"
69 #include "nfsnode.h"
70 #include "xdr_subs.h"
71 #include "nfsm_subs.h"
72 
73 
74 static struct buf *nfs_getcacheblk(struct vnode *vp, off_t loffset,
75 				   int size, struct thread *td);
76 static int nfs_check_dirent(struct nfs_dirent *dp, int maxlen);
77 static void nfsiodone_sync(struct bio *bio);
78 static void nfs_readrpc_bio_done(nfsm_info_t info);
79 static void nfs_writerpc_bio_done(nfsm_info_t info);
80 static void nfs_commitrpc_bio_done(nfsm_info_t info);
81 
82 /*
83  * Vnode op for read using bio
84  */
85 int
86 nfs_bioread(struct vnode *vp, struct uio *uio, int ioflag)
87 {
88 	struct nfsnode *np = VTONFS(vp);
89 	int biosize, i;
90 	struct buf *bp, *rabp;
91 	struct vattr vattr;
92 	struct thread *td;
93 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
94 	off_t lbn, rabn;
95 	off_t raoffset;
96 	off_t loffset;
97 	int seqcount;
98 	int nra, error = 0;
99 	int boff = 0;
100 	size_t n;
101 
102 #ifdef DIAGNOSTIC
103 	if (uio->uio_rw != UIO_READ)
104 		panic("nfs_read mode");
105 #endif
106 	if (uio->uio_resid == 0)
107 		return (0);
108 	if (uio->uio_offset < 0)	/* XXX VDIR cookies can be negative */
109 		return (EINVAL);
110 	td = uio->uio_td;
111 
112 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
113 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
114 		(void)nfs_fsinfo(nmp, vp, td);
115 	if (vp->v_type != VDIR &&
116 	    (uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
117 		return (EFBIG);
118 	biosize = vp->v_mount->mnt_stat.f_iosize;
119 	seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
120 
121 	/*
122 	 * For nfs, cache consistency can only be maintained approximately.
123 	 * Although RFC1094 does not specify the criteria, the following is
124 	 * believed to be compatible with the reference port.
125 	 *
126 	 * NFS:		If local changes have been made and this is a
127 	 *		directory, the directory must be invalidated and
128 	 *		the attribute cache must be cleared.
129 	 *
130 	 *		GETATTR is called to synchronize the file size.
131 	 *
132 	 *		If remote changes are detected local data is flushed
133 	 *		and the cache is invalidated.
134 	 *
135 	 *		NOTE: In the normal case the attribute cache is not
136 	 *		cleared which means GETATTR may use cached data and
137 	 *		not immediately detect changes made on the server.
138 	 */
139 	if ((np->n_flag & NLMODIFIED) && vp->v_type == VDIR) {
140 		nfs_invaldir(vp);
141 		error = nfs_vinvalbuf(vp, V_SAVE, 1);
142 		if (error)
143 			return (error);
144 		np->n_attrstamp = 0;
145 	}
146 	error = VOP_GETATTR(vp, &vattr);
147 	if (error)
148 		return (error);
149 
150 	/*
151 	 * This can deadlock getpages/putpages for regular
152 	 * files.  Only do it for directories.
153 	 */
154 	if (np->n_flag & NRMODIFIED) {
155 		if (vp->v_type == VDIR) {
156 			nfs_invaldir(vp);
157 			error = nfs_vinvalbuf(vp, V_SAVE, 1);
158 			if (error)
159 				return (error);
160 			np->n_flag &= ~NRMODIFIED;
161 		}
162 	}
163 
164 	/*
165 	 * Loop until uio exhausted or we hit EOF
166 	 */
167 	do {
168 	    bp = NULL;
169 
170 	    switch (vp->v_type) {
171 	    case VREG:
172 		nfsstats.biocache_reads++;
173 		lbn = uio->uio_offset / biosize;
174 		boff = uio->uio_offset & (biosize - 1);
175 		loffset = (off_t)lbn * biosize;
176 
177 		/*
178 		 * Start the read ahead(s), as required.
179 		 */
180 		if (nmp->nm_readahead > 0 && nfs_asyncok(nmp)) {
181 		    for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
182 			(off_t)(lbn + 1 + nra) * biosize < np->n_size; nra++) {
183 			rabn = lbn + 1 + nra;
184 			raoffset = (off_t)rabn * biosize;
185 			if (findblk(vp, raoffset, FINDBLK_TEST) == NULL) {
186 			    rabp = nfs_getcacheblk(vp, raoffset, biosize, td);
187 			    if (!rabp)
188 				return (EINTR);
189 			    if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
190 				rabp->b_cmd = BUF_CMD_READ;
191 				vfs_busy_pages(vp, rabp);
192 				nfs_asyncio(vp, &rabp->b_bio2);
193 			    } else {
194 				brelse(rabp);
195 			    }
196 			}
197 		    }
198 		}
199 
200 		/*
201 		 * Obtain the buffer cache block.  Figure out the buffer size
202 		 * when we are at EOF.  If we are modifying the size of the
203 		 * buffer based on an EOF condition we need to hold
204 		 * nfs_rslock() through obtaining the buffer to prevent
205 		 * a potential writer-appender from messing with n_size.
206 		 * Otherwise we may accidently truncate the buffer and
207 		 * lose dirty data.
208 		 *
209 		 * Note that bcount is *not* DEV_BSIZE aligned.
210 		 */
211 		if (loffset + boff >= np->n_size) {
212 			n = 0;
213 			break;
214 		}
215 		bp = nfs_getcacheblk(vp, loffset, biosize, td);
216 
217 		if (bp == NULL)
218 			return (EINTR);
219 
220 		/*
221 		 * If B_CACHE is not set, we must issue the read.  If this
222 		 * fails, we return an error.
223 		 */
224 		if ((bp->b_flags & B_CACHE) == 0) {
225 			bp->b_cmd = BUF_CMD_READ;
226 			bp->b_bio2.bio_done = nfsiodone_sync;
227 			bp->b_bio2.bio_flags |= BIO_SYNC;
228 			vfs_busy_pages(vp, bp);
229 			error = nfs_doio(vp, &bp->b_bio2, td);
230 			if (error) {
231 				brelse(bp);
232 				return (error);
233 			}
234 		}
235 
236 		/*
237 		 * on is the offset into the current bp.  Figure out how many
238 		 * bytes we can copy out of the bp.  Note that bcount is
239 		 * NOT DEV_BSIZE aligned.
240 		 *
241 		 * Then figure out how many bytes we can copy into the uio.
242 		 */
243 		n = biosize - boff;
244 		if (n > uio->uio_resid)
245 			n = uio->uio_resid;
246 		if (loffset + boff + n > np->n_size)
247 			n = np->n_size - loffset - boff;
248 		break;
249 	    case VLNK:
250 		biosize = min(NFS_MAXPATHLEN, np->n_size);
251 		nfsstats.biocache_readlinks++;
252 		bp = nfs_getcacheblk(vp, (off_t)0, biosize, td);
253 		if (bp == NULL)
254 			return (EINTR);
255 		if ((bp->b_flags & B_CACHE) == 0) {
256 			bp->b_cmd = BUF_CMD_READ;
257 			bp->b_bio2.bio_done = nfsiodone_sync;
258 			bp->b_bio2.bio_flags |= BIO_SYNC;
259 			vfs_busy_pages(vp, bp);
260 			error = nfs_doio(vp, &bp->b_bio2, td);
261 			if (error) {
262 				bp->b_flags |= B_ERROR | B_INVAL;
263 				brelse(bp);
264 				return (error);
265 			}
266 		}
267 		n = szmin(uio->uio_resid, (size_t)bp->b_bcount - bp->b_resid);
268 		boff = 0;
269 		break;
270 	    case VDIR:
271 		nfsstats.biocache_readdirs++;
272 		if (np->n_direofoffset &&
273 		    uio->uio_offset >= np->n_direofoffset
274 		) {
275 			return (0);
276 		}
277 		lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
278 		boff = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
279 		loffset = uio->uio_offset - boff;
280 		bp = nfs_getcacheblk(vp, loffset, NFS_DIRBLKSIZ, td);
281 		if (bp == NULL)
282 			return (EINTR);
283 
284 		if ((bp->b_flags & B_CACHE) == 0) {
285 		    bp->b_cmd = BUF_CMD_READ;
286 		    bp->b_bio2.bio_done = nfsiodone_sync;
287 		    bp->b_bio2.bio_flags |= BIO_SYNC;
288 		    vfs_busy_pages(vp, bp);
289 		    error = nfs_doio(vp, &bp->b_bio2, td);
290 		    if (error)
291 			    brelse(bp);
292 		    while (error == NFSERR_BAD_COOKIE) {
293 			kprintf("got bad cookie vp %p bp %p\n", vp, bp);
294 			nfs_invaldir(vp);
295 			error = nfs_vinvalbuf(vp, 0, 1);
296 			/*
297 			 * Yuck! The directory has been modified on the
298 			 * server. The only way to get the block is by
299 			 * reading from the beginning to get all the
300 			 * offset cookies.
301 			 *
302 			 * Leave the last bp intact unless there is an error.
303 			 * Loop back up to the while if the error is another
304 			 * NFSERR_BAD_COOKIE (double yuch!).
305 			 */
306 			for (i = 0; i <= lbn && !error; i++) {
307 			    if (np->n_direofoffset
308 				&& (i * NFS_DIRBLKSIZ) >= np->n_direofoffset)
309 				    return (0);
310 			    bp = nfs_getcacheblk(vp, (off_t)i * NFS_DIRBLKSIZ,
311 						 NFS_DIRBLKSIZ, td);
312 			    if (!bp)
313 				return (EINTR);
314 			    if ((bp->b_flags & B_CACHE) == 0) {
315 				    bp->b_cmd = BUF_CMD_READ;
316 				    bp->b_bio2.bio_done = nfsiodone_sync;
317 				    bp->b_bio2.bio_flags |= BIO_SYNC;
318 				    vfs_busy_pages(vp, bp);
319 				    error = nfs_doio(vp, &bp->b_bio2, td);
320 				    /*
321 				     * no error + B_INVAL == directory EOF,
322 				     * use the block.
323 				     */
324 				    if (error == 0 && (bp->b_flags & B_INVAL))
325 					    break;
326 			    }
327 			    /*
328 			     * An error will throw away the block and the
329 			     * for loop will break out.  If no error and this
330 			     * is not the block we want, we throw away the
331 			     * block and go for the next one via the for loop.
332 			     */
333 			    if (error || i < lbn)
334 				    brelse(bp);
335 			}
336 		    }
337 		    /*
338 		     * The above while is repeated if we hit another cookie
339 		     * error.  If we hit an error and it wasn't a cookie error,
340 		     * we give up.
341 		     */
342 		    if (error)
343 			    return (error);
344 		}
345 
346 		/*
347 		 * If not eof and read aheads are enabled, start one.
348 		 * (You need the current block first, so that you have the
349 		 *  directory offset cookie of the next block.)
350 		 */
351 		if (nmp->nm_readahead > 0 && nfs_asyncok(nmp) &&
352 		    (bp->b_flags & B_INVAL) == 0 &&
353 		    (np->n_direofoffset == 0 ||
354 		    loffset + NFS_DIRBLKSIZ < np->n_direofoffset) &&
355 		    findblk(vp, loffset + NFS_DIRBLKSIZ, FINDBLK_TEST) == NULL
356 		) {
357 			rabp = nfs_getcacheblk(vp, loffset + NFS_DIRBLKSIZ,
358 					       NFS_DIRBLKSIZ, td);
359 			if (rabp) {
360 			    if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
361 				rabp->b_cmd = BUF_CMD_READ;
362 				vfs_busy_pages(vp, rabp);
363 				nfs_asyncio(vp, &rabp->b_bio2);
364 			    } else {
365 				brelse(rabp);
366 			    }
367 			}
368 		}
369 		/*
370 		 * Unlike VREG files, whos buffer size ( bp->b_bcount ) is
371 		 * chopped for the EOF condition, we cannot tell how large
372 		 * NFS directories are going to be until we hit EOF.  So
373 		 * an NFS directory buffer is *not* chopped to its EOF.  Now,
374 		 * it just so happens that b_resid will effectively chop it
375 		 * to EOF.  *BUT* this information is lost if the buffer goes
376 		 * away and is reconstituted into a B_CACHE state ( due to
377 		 * being VMIO ) later.  So we keep track of the directory eof
378 		 * in np->n_direofoffset and chop it off as an extra step
379 		 * right here.
380 		 *
381 		 * NOTE: boff could already be beyond EOF.
382 		 */
383 		if ((size_t)boff > NFS_DIRBLKSIZ - bp->b_resid) {
384 			n = 0;
385 		} else {
386 			n = szmin(uio->uio_resid,
387 				  NFS_DIRBLKSIZ - bp->b_resid - (size_t)boff);
388 		}
389 		if (np->n_direofoffset &&
390 		    n > (size_t)(np->n_direofoffset - uio->uio_offset)) {
391 			n = (size_t)(np->n_direofoffset - uio->uio_offset);
392 		}
393 		break;
394 	    default:
395 		kprintf(" nfs_bioread: type %x unexpected\n",vp->v_type);
396 		n = 0;
397 		break;
398 	    };
399 
400 	    switch (vp->v_type) {
401 	    case VREG:
402 		if (n > 0)
403 		    error = uiomove(bp->b_data + boff, n, uio);
404 		break;
405 	    case VLNK:
406 		if (n > 0)
407 		    error = uiomove(bp->b_data + boff, n, uio);
408 		n = 0;
409 		break;
410 	    case VDIR:
411 		if (n > 0) {
412 		    off_t old_off = uio->uio_offset;
413 		    caddr_t cpos, epos;
414 		    struct nfs_dirent *dp;
415 
416 		    /*
417 		     * We are casting cpos to nfs_dirent, it must be
418 		     * int-aligned.
419 		     */
420 		    if (boff & 3) {
421 			error = EINVAL;
422 			break;
423 		    }
424 
425 		    cpos = bp->b_data + boff;
426 		    epos = bp->b_data + boff + n;
427 		    while (cpos < epos && error == 0 && uio->uio_resid > 0) {
428 			    dp = (struct nfs_dirent *)cpos;
429 			    error = nfs_check_dirent(dp, (int)(epos - cpos));
430 			    if (error)
431 				    break;
432 			    if (vop_write_dirent(&error, uio, dp->nfs_ino,
433 				dp->nfs_type, dp->nfs_namlen, dp->nfs_name)) {
434 				    break;
435 			    }
436 			    cpos += dp->nfs_reclen;
437 		    }
438 		    n = 0;
439 		    if (error == 0) {
440 			    uio->uio_offset = old_off + cpos -
441 					      bp->b_data - boff;
442 		    }
443 		}
444 		break;
445 	    default:
446 		kprintf(" nfs_bioread: type %x unexpected\n",vp->v_type);
447 	    }
448 	    if (bp)
449 		    brelse(bp);
450 	} while (error == 0 && uio->uio_resid > 0 && n > 0);
451 	return (error);
452 }
453 
454 /*
455  * Userland can supply any 'seek' offset when reading a NFS directory.
456  * Validate the structure so we don't panic the kernel.  Note that
457  * the element name is nul terminated and the nul is not included
458  * in nfs_namlen.
459  */
460 static
461 int
462 nfs_check_dirent(struct nfs_dirent *dp, int maxlen)
463 {
464 	int nfs_name_off = offsetof(struct nfs_dirent, nfs_name[0]);
465 
466 	if (nfs_name_off >= maxlen)
467 		return (EINVAL);
468 	if (dp->nfs_reclen < nfs_name_off || dp->nfs_reclen > maxlen)
469 		return (EINVAL);
470 	if (nfs_name_off + dp->nfs_namlen >= dp->nfs_reclen)
471 		return (EINVAL);
472 	if (dp->nfs_reclen & 3)
473 		return (EINVAL);
474 	return (0);
475 }
476 
477 /*
478  * Vnode op for write using bio
479  *
480  * nfs_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
481  *	     struct ucred *a_cred)
482  */
483 int
484 nfs_write(struct vop_write_args *ap)
485 {
486 	struct uio *uio = ap->a_uio;
487 	struct thread *td = uio->uio_td;
488 	struct vnode *vp = ap->a_vp;
489 	struct nfsnode *np = VTONFS(vp);
490 	int ioflag = ap->a_ioflag;
491 	struct buf *bp;
492 	struct vattr vattr;
493 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
494 	off_t loffset;
495 	int boff, bytes;
496 	int error = 0;
497 	int haverslock = 0;
498 	int bcount;
499 	int biosize;
500 	int trivial;
501 
502 #ifdef DIAGNOSTIC
503 	if (uio->uio_rw != UIO_WRITE)
504 		panic("nfs_write mode");
505 	if (uio->uio_segflg == UIO_USERSPACE && uio->uio_td != curthread)
506 		panic("nfs_write proc");
507 #endif
508 	if (vp->v_type != VREG)
509 		return (EIO);
510 	if (np->n_flag & NWRITEERR) {
511 		np->n_flag &= ~NWRITEERR;
512 		return (np->n_error);
513 	}
514 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
515 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
516 		(void)nfs_fsinfo(nmp, vp, td);
517 
518 	/*
519 	 * Synchronously flush pending buffers if we are in synchronous
520 	 * mode or if we are appending.
521 	 */
522 	if (ioflag & (IO_APPEND | IO_SYNC)) {
523 		if (np->n_flag & NLMODIFIED) {
524 			np->n_attrstamp = 0;
525 			error = nfs_flush(vp, MNT_WAIT, td, 0);
526 			/* error = nfs_vinvalbuf(vp, V_SAVE, 1); */
527 			if (error)
528 				return (error);
529 		}
530 	}
531 
532 	/*
533 	 * If IO_APPEND then load uio_offset.  We restart here if we cannot
534 	 * get the append lock.
535 	 */
536 restart:
537 	if (ioflag & IO_APPEND) {
538 		np->n_attrstamp = 0;
539 		error = VOP_GETATTR(vp, &vattr);
540 		if (error)
541 			return (error);
542 		uio->uio_offset = np->n_size;
543 	}
544 
545 	if (uio->uio_offset < 0)
546 		return (EINVAL);
547 	if ((uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
548 		return (EFBIG);
549 	if (uio->uio_resid == 0)
550 		return (0);
551 
552 	/*
553 	 * We need to obtain the rslock if we intend to modify np->n_size
554 	 * in order to guarentee the append point with multiple contending
555 	 * writers, to guarentee that no other appenders modify n_size
556 	 * while we are trying to obtain a truncated buffer (i.e. to avoid
557 	 * accidently truncating data written by another appender due to
558 	 * the race), and to ensure that the buffer is populated prior to
559 	 * our extending of the file.  We hold rslock through the entire
560 	 * operation.
561 	 *
562 	 * Note that we do not synchronize the case where someone truncates
563 	 * the file while we are appending to it because attempting to lock
564 	 * this case may deadlock other parts of the system unexpectedly.
565 	 */
566 	if ((ioflag & IO_APPEND) ||
567 	    uio->uio_offset + uio->uio_resid > np->n_size) {
568 		switch(nfs_rslock(np)) {
569 		case ENOLCK:
570 			goto restart;
571 			/* not reached */
572 		case EINTR:
573 		case ERESTART:
574 			return(EINTR);
575 			/* not reached */
576 		default:
577 			break;
578 		}
579 		haverslock = 1;
580 	}
581 
582 	/*
583 	 * Maybe this should be above the vnode op call, but so long as
584 	 * file servers have no limits, i don't think it matters
585 	 */
586 	if (td && td->td_proc && uio->uio_offset + uio->uio_resid >
587 	      td->td_proc->p_rlimit[RLIMIT_FSIZE].rlim_cur) {
588 		lwpsignal(td->td_proc, td->td_lwp, SIGXFSZ);
589 		if (haverslock)
590 			nfs_rsunlock(np);
591 		return (EFBIG);
592 	}
593 
594 	biosize = vp->v_mount->mnt_stat.f_iosize;
595 
596 	do {
597 		nfsstats.biocache_writes++;
598 		boff = uio->uio_offset & (biosize-1);
599 		loffset = uio->uio_offset - boff;
600 		bytes = (int)szmin((unsigned)(biosize - boff), uio->uio_resid);
601 again:
602 		/*
603 		 * Handle direct append and file extension cases, calculate
604 		 * unaligned buffer size.  When extending B_CACHE will be
605 		 * set if possible.  See UIO_NOCOPY note below.
606 		 */
607 		if (uio->uio_offset + bytes > np->n_size) {
608 			np->n_flag |= NLMODIFIED;
609 			trivial = (uio->uio_segflg != UIO_NOCOPY &&
610 				   uio->uio_offset <= np->n_size);
611 			nfs_meta_setsize(vp, td, uio->uio_offset + bytes,
612 					 trivial);
613 		}
614 		bp = nfs_getcacheblk(vp, loffset, biosize, td);
615 		if (bp == NULL) {
616 			error = EINTR;
617 			break;
618 		}
619 
620 		/*
621 		 * Actual bytes in buffer which we care about
622 		 */
623 		if (loffset + biosize < np->n_size)
624 			bcount = biosize;
625 		else
626 			bcount = (int)(np->n_size - loffset);
627 
628 		/*
629 		 * Avoid a read by setting B_CACHE where the data we
630 		 * intend to write covers the entire buffer.  Note
631 		 * that the buffer may have been set to B_CACHE by
632 		 * nfs_meta_setsize() above or otherwise inherited the
633 		 * flag, but if B_CACHE isn't set the buffer may be
634 		 * uninitialized and must be zero'd to accomodate
635 		 * future seek+write's.
636 		 *
637 		 * See the comments in kern/vfs_bio.c's getblk() for
638 		 * more information.
639 		 *
640 		 * When doing a UIO_NOCOPY write the buffer is not
641 		 * overwritten and we cannot just set B_CACHE unconditionally
642 		 * for full-block writes.
643 		 */
644 		if (boff == 0 && bytes == biosize &&
645 		    uio->uio_segflg != UIO_NOCOPY) {
646 			bp->b_flags |= B_CACHE;
647 			bp->b_flags &= ~(B_ERROR | B_INVAL);
648 		}
649 
650 		/*
651 		 * b_resid may be set due to file EOF if we extended out.
652 		 * The NFS bio code will zero the difference anyway so
653 		 * just acknowledged the fact and set b_resid to 0.
654 		 */
655 		if ((bp->b_flags & B_CACHE) == 0) {
656 			bp->b_cmd = BUF_CMD_READ;
657 			bp->b_bio2.bio_done = nfsiodone_sync;
658 			bp->b_bio2.bio_flags |= BIO_SYNC;
659 			vfs_busy_pages(vp, bp);
660 			error = nfs_doio(vp, &bp->b_bio2, td);
661 			if (error) {
662 				brelse(bp);
663 				break;
664 			}
665 			bp->b_resid = 0;
666 		}
667 		np->n_flag |= NLMODIFIED;
668 
669 		/*
670 		 * If dirtyend exceeds file size, chop it down.  This should
671 		 * not normally occur but there is an append race where it
672 		 * might occur XXX, so we log it.
673 		 *
674 		 * If the chopping creates a reverse-indexed or degenerate
675 		 * situation with dirtyoff/end, we 0 both of them.
676 		 */
677 		if (bp->b_dirtyend > bcount) {
678 			kprintf("NFS append race @%08llx:%d\n",
679 			    (long long)bp->b_bio2.bio_offset,
680 			    bp->b_dirtyend - bcount);
681 			bp->b_dirtyend = bcount;
682 		}
683 
684 		if (bp->b_dirtyoff >= bp->b_dirtyend)
685 			bp->b_dirtyoff = bp->b_dirtyend = 0;
686 
687 		/*
688 		 * If the new write will leave a contiguous dirty
689 		 * area, just update the b_dirtyoff and b_dirtyend,
690 		 * otherwise force a write rpc of the old dirty area.
691 		 *
692 		 * While it is possible to merge discontiguous writes due to
693 		 * our having a B_CACHE buffer ( and thus valid read data
694 		 * for the hole), we don't because it could lead to
695 		 * significant cache coherency problems with multiple clients,
696 		 * especially if locking is implemented later on.
697 		 *
698 		 * as an optimization we could theoretically maintain
699 		 * a linked list of discontinuous areas, but we would still
700 		 * have to commit them separately so there isn't much
701 		 * advantage to it except perhaps a bit of asynchronization.
702 		 */
703 		if (bp->b_dirtyend > 0 &&
704 		    (boff > bp->b_dirtyend ||
705 		     (boff + bytes) < bp->b_dirtyoff)
706 		) {
707 			if (bwrite(bp) == EINTR) {
708 				error = EINTR;
709 				break;
710 			}
711 			goto again;
712 		}
713 
714 		error = uiomove(bp->b_data + boff, bytes, uio);
715 
716 		/*
717 		 * Since this block is being modified, it must be written
718 		 * again and not just committed.  Since write clustering does
719 		 * not work for the stage 1 data write, only the stage 2
720 		 * commit rpc, we have to clear B_CLUSTEROK as well.
721 		 */
722 		bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
723 
724 		if (error) {
725 			brelse(bp);
726 			break;
727 		}
728 
729 		/*
730 		 * Only update dirtyoff/dirtyend if not a degenerate
731 		 * condition.
732 		 *
733 		 * The underlying VM pages have been marked valid by
734 		 * virtue of acquiring the bp.  Because the entire buffer
735 		 * is marked dirty we do not have to worry about cleaning
736 		 * out the related dirty bits (and wouldn't really know
737 		 * how to deal with byte ranges anyway)
738 		 */
739 		if (bytes) {
740 			if (bp->b_dirtyend > 0) {
741 				bp->b_dirtyoff = imin(boff, bp->b_dirtyoff);
742 				bp->b_dirtyend = imax(boff + bytes,
743 						      bp->b_dirtyend);
744 			} else {
745 				bp->b_dirtyoff = boff;
746 				bp->b_dirtyend = boff + bytes;
747 			}
748 		}
749 
750 		/*
751 		 * If the lease is non-cachable or IO_SYNC do bwrite().
752 		 *
753 		 * IO_INVAL appears to be unused.  The idea appears to be
754 		 * to turn off caching in this case.  Very odd.  XXX
755 		 *
756 		 * If nfs_async is set bawrite() will use an unstable write
757 		 * (build dirty bufs on the server), so we might as well
758 		 * push it out with bawrite().  If nfs_async is not set we
759 		 * use bdwrite() to cache dirty bufs on the client.
760 		 */
761 		if (ioflag & IO_SYNC) {
762 			if (ioflag & IO_INVAL)
763 				bp->b_flags |= B_NOCACHE;
764 			error = bwrite(bp);
765 			if (error)
766 				break;
767 		} else if (boff + bytes == biosize && nfs_async) {
768 			bawrite(bp);
769 		} else {
770 			bdwrite(bp);
771 		}
772 	} while (uio->uio_resid > 0 && bytes > 0);
773 
774 	if (haverslock)
775 		nfs_rsunlock(np);
776 
777 	return (error);
778 }
779 
780 /*
781  * Get an nfs cache block.
782  *
783  * Allocate a new one if the block isn't currently in the cache
784  * and return the block marked busy. If the calling process is
785  * interrupted by a signal for an interruptible mount point, return
786  * NULL.
787  *
788  * The caller must carefully deal with the possible B_INVAL state of
789  * the buffer.  nfs_startio() clears B_INVAL (and nfs_asyncio() clears it
790  * indirectly), so synchronous reads can be issued without worrying about
791  * the B_INVAL state.  We have to be a little more careful when dealing
792  * with writes (see comments in nfs_write()) when extending a file past
793  * its EOF.
794  */
795 static struct buf *
796 nfs_getcacheblk(struct vnode *vp, off_t loffset, int size, struct thread *td)
797 {
798 	struct buf *bp;
799 	struct mount *mp;
800 	struct nfsmount *nmp;
801 
802 	mp = vp->v_mount;
803 	nmp = VFSTONFS(mp);
804 
805 	if (nmp->nm_flag & NFSMNT_INT) {
806 		bp = getblk(vp, loffset, size, GETBLK_PCATCH, 0);
807 		while (bp == NULL) {
808 			if (nfs_sigintr(nmp, NULL, td))
809 				return (NULL);
810 			bp = getblk(vp, loffset, size, 0, 2 * hz);
811 		}
812 	} else {
813 		bp = getblk(vp, loffset, size, 0, 0);
814 	}
815 
816 	/*
817 	 * bio2, the 'device' layer.  Since BIOs use 64 bit byte offsets
818 	 * now, no translation is necessary.
819 	 */
820 	bp->b_bio2.bio_offset = loffset;
821 	return (bp);
822 }
823 
824 /*
825  * Flush and invalidate all dirty buffers. If another process is already
826  * doing the flush, just wait for completion.
827  */
828 int
829 nfs_vinvalbuf(struct vnode *vp, int flags, int intrflg)
830 {
831 	struct nfsnode *np = VTONFS(vp);
832 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
833 	int error = 0, slpflag, slptimeo;
834 	thread_t td = curthread;
835 
836 	if (vp->v_flag & VRECLAIMED)
837 		return (0);
838 
839 	if ((nmp->nm_flag & NFSMNT_INT) == 0)
840 		intrflg = 0;
841 	if (intrflg) {
842 		slpflag = PCATCH;
843 		slptimeo = 2 * hz;
844 	} else {
845 		slpflag = 0;
846 		slptimeo = 0;
847 	}
848 	/*
849 	 * First wait for any other process doing a flush to complete.
850 	 */
851 	while (np->n_flag & NFLUSHINPROG) {
852 		np->n_flag |= NFLUSHWANT;
853 		error = tsleep((caddr_t)&np->n_flag, 0, "nfsvinval", slptimeo);
854 		if (error && intrflg && nfs_sigintr(nmp, NULL, td))
855 			return (EINTR);
856 	}
857 
858 	/*
859 	 * Now, flush as required.
860 	 */
861 	np->n_flag |= NFLUSHINPROG;
862 	error = vinvalbuf(vp, flags, slpflag, 0);
863 	while (error) {
864 		if (intrflg && nfs_sigintr(nmp, NULL, td)) {
865 			np->n_flag &= ~NFLUSHINPROG;
866 			if (np->n_flag & NFLUSHWANT) {
867 				np->n_flag &= ~NFLUSHWANT;
868 				wakeup((caddr_t)&np->n_flag);
869 			}
870 			return (EINTR);
871 		}
872 		error = vinvalbuf(vp, flags, 0, slptimeo);
873 	}
874 	np->n_flag &= ~(NLMODIFIED | NFLUSHINPROG);
875 	if (np->n_flag & NFLUSHWANT) {
876 		np->n_flag &= ~NFLUSHWANT;
877 		wakeup((caddr_t)&np->n_flag);
878 	}
879 	return (0);
880 }
881 
882 /*
883  * Return true (non-zero) if the txthread and rxthread are operational
884  * and we do not already have too many not-yet-started BIO's built up.
885  */
886 int
887 nfs_asyncok(struct nfsmount *nmp)
888 {
889 	return (nmp->nm_bioqlen < nfs_maxasyncbio &&
890 		nmp->nm_bioqlen < nmp->nm_maxasync_scaled / NFS_ASYSCALE &&
891 		nmp->nm_rxstate <= NFSSVC_PENDING &&
892 		nmp->nm_txstate <= NFSSVC_PENDING);
893 }
894 
895 /*
896  * The read-ahead code calls this to queue a bio to the txthread.
897  *
898  * We don't touch the bio otherwise... that is, we do not even
899  * construct or send the initial rpc.  The txthread will do it
900  * for us.
901  *
902  * NOTE!  nm_bioqlen is not decremented until the request completes,
903  *	  so it does not reflect the number of bio's on bioq.
904  */
905 void
906 nfs_asyncio(struct vnode *vp, struct bio *bio)
907 {
908 	struct buf *bp = bio->bio_buf;
909 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
910 
911 	KKASSERT(vp->v_tag == VT_NFS);
912 	BUF_KERNPROC(bp);
913 
914 	/*
915 	 * Shortcut swap cache (not done automatically because we are not
916 	 * using bread()).
917 	 */
918 	if (vn_cache_strategy(vp, bio))
919 		return;
920 
921 	bio->bio_driver_info = vp;
922 	crit_enter();
923 	TAILQ_INSERT_TAIL(&nmp->nm_bioq, bio, bio_act);
924 	atomic_add_int(&nmp->nm_bioqlen, 1);
925 	crit_exit();
926 	nfssvc_iod_writer_wakeup(nmp);
927 }
928 
929 /*
930  * nfs_dio()	- Execute a BIO operation synchronously.  The BIO will be
931  *		  completed and its error returned.  The caller is responsible
932  *		  for brelse()ing it.  ONLY USE FOR BIO_SYNC IOs!  Otherwise
933  *		  our error probe will be against an invalid pointer.
934  *
935  * nfs_startio()- Execute a BIO operation assynchronously.
936  *
937  * NOTE: nfs_asyncio() is used to initiate an asynchronous BIO operation,
938  *	 which basically just queues it to the txthread.  nfs_startio()
939  *	 actually initiates the I/O AFTER it has gotten to the txthread.
940  *
941  * NOTE: td might be NULL.
942  *
943  * NOTE: Caller has already busied the I/O.
944  */
945 void
946 nfs_startio(struct vnode *vp, struct bio *bio, struct thread *td)
947 {
948 	struct buf *bp = bio->bio_buf;
949 	struct nfsnode *np;
950 	struct nfsmount *nmp;
951 
952 	KKASSERT(vp->v_tag == VT_NFS);
953 	np = VTONFS(vp);
954 	nmp = VFSTONFS(vp->v_mount);
955 
956 	/*
957 	 * clear B_ERROR and B_INVAL state prior to initiating the I/O.  We
958 	 * do this here so we do not have to do it in all the code that
959 	 * calls us.
960 	 */
961 	bp->b_flags &= ~(B_ERROR | B_INVAL);
962 
963 	KASSERT(bp->b_cmd != BUF_CMD_DONE,
964 		("nfs_doio: bp %p already marked done!", bp));
965 
966 	if (bp->b_cmd == BUF_CMD_READ) {
967 	    switch (vp->v_type) {
968 	    case VREG:
969 		nfsstats.read_bios++;
970 		nfs_readrpc_bio(vp, bio);
971 		break;
972 	    case VLNK:
973 #if 0
974 		bio->bio_offset = 0;
975 		nfsstats.readlink_bios++;
976 		nfs_readlinkrpc_bio(vp, bio);
977 #else
978 		nfs_doio(vp, bio, td);
979 #endif
980 		break;
981 	    case VDIR:
982 		/*
983 		 * NOTE: If nfs_readdirplusrpc_bio() is requested but
984 		 *	 not supported, it will chain to
985 		 *	 nfs_readdirrpc_bio().
986 		 */
987 #if 0
988 		nfsstats.readdir_bios++;
989 		uiop->uio_offset = bio->bio_offset;
990 		if (nmp->nm_flag & NFSMNT_RDIRPLUS)
991 			nfs_readdirplusrpc_bio(vp, bio);
992 		else
993 			nfs_readdirrpc_bio(vp, bio);
994 #else
995 		nfs_doio(vp, bio, td);
996 #endif
997 		break;
998 	    default:
999 		kprintf("nfs_doio:  type %x unexpected\n",vp->v_type);
1000 		bp->b_flags |= B_ERROR;
1001 		bp->b_error = EINVAL;
1002 		biodone(bio);
1003 		break;
1004 	    }
1005 	} else {
1006 	    /*
1007 	     * If we only need to commit, try to commit.  If this fails
1008 	     * it will chain through to the write.  Basically all the logic
1009 	     * in nfs_doio() is replicated.
1010 	     */
1011 	    KKASSERT(bp->b_cmd == BUF_CMD_WRITE);
1012 	    if (bp->b_flags & B_NEEDCOMMIT)
1013 		nfs_commitrpc_bio(vp, bio);
1014 	    else
1015 		nfs_writerpc_bio(vp, bio);
1016 	}
1017 }
1018 
1019 int
1020 nfs_doio(struct vnode *vp, struct bio *bio, struct thread *td)
1021 {
1022 	struct buf *bp = bio->bio_buf;
1023 	struct uio *uiop;
1024 	struct nfsnode *np;
1025 	struct nfsmount *nmp;
1026 	int error = 0;
1027 	int iomode, must_commit;
1028 	size_t n;
1029 	struct uio uio;
1030 	struct iovec io;
1031 
1032 #if 0
1033 	/*
1034 	 * Shortcut swap cache (not done automatically because we are not
1035 	 * using bread()).
1036 	 *
1037 	 * XXX The biowait is a hack until we can figure out how to stop a
1038 	 * biodone chain when a middle element is BIO_SYNC.  BIO_SYNC is
1039 	 * set so the bp shouldn't get ripped out from under us.  The only
1040 	 * use-cases are fully synchronous I/O cases.
1041 	 *
1042 	 * XXX This is having problems, give up for now.
1043 	 */
1044 	if (vn_cache_strategy(vp, bio)) {
1045 		kprintf("X");
1046 		error = biowait(&bio->bio_buf->b_bio1, "nfsrsw");
1047 		return (error);
1048 	}
1049 #endif
1050 
1051 	KKASSERT(vp->v_tag == VT_NFS);
1052 	np = VTONFS(vp);
1053 	nmp = VFSTONFS(vp->v_mount);
1054 	uiop = &uio;
1055 	uiop->uio_iov = &io;
1056 	uiop->uio_iovcnt = 1;
1057 	uiop->uio_segflg = UIO_SYSSPACE;
1058 	uiop->uio_td = td;
1059 
1060 	/*
1061 	 * clear B_ERROR and B_INVAL state prior to initiating the I/O.  We
1062 	 * do this here so we do not have to do it in all the code that
1063 	 * calls us.
1064 	 */
1065 	bp->b_flags &= ~(B_ERROR | B_INVAL);
1066 
1067 	KASSERT(bp->b_cmd != BUF_CMD_DONE,
1068 		("nfs_doio: bp %p already marked done!", bp));
1069 
1070 	if (bp->b_cmd == BUF_CMD_READ) {
1071 	    io.iov_len = uiop->uio_resid = (size_t)bp->b_bcount;
1072 	    io.iov_base = bp->b_data;
1073 	    uiop->uio_rw = UIO_READ;
1074 
1075 	    switch (vp->v_type) {
1076 	    case VREG:
1077 		/*
1078 		 * When reading from a regular file zero-fill any residual.
1079 		 * Note that this residual has nothing to do with NFS short
1080 		 * reads, which nfs_readrpc_uio() will handle for us.
1081 		 *
1082 		 * We have to do this because when we are write extending
1083 		 * a file the server may not have the same notion of
1084 		 * filesize as we do.  Our BIOs should already be sized
1085 		 * (b_bcount) to account for the file EOF.
1086 		 */
1087 		nfsstats.read_bios++;
1088 		uiop->uio_offset = bio->bio_offset;
1089 		error = nfs_readrpc_uio(vp, uiop);
1090 		if (error == 0 && uiop->uio_resid) {
1091 			n = (size_t)bp->b_bcount - uiop->uio_resid;
1092 			bzero(bp->b_data + n, bp->b_bcount - n);
1093 			uiop->uio_resid = 0;
1094 		}
1095 		if (td && td->td_proc && (vp->v_flag & VTEXT) &&
1096 		    np->n_mtime != np->n_vattr.va_mtime.tv_sec) {
1097 			uprintf("Process killed due to text file modification\n");
1098 			ksignal(td->td_proc, SIGKILL);
1099 		}
1100 		break;
1101 	    case VLNK:
1102 		uiop->uio_offset = 0;
1103 		nfsstats.readlink_bios++;
1104 		error = nfs_readlinkrpc_uio(vp, uiop);
1105 		break;
1106 	    case VDIR:
1107 		nfsstats.readdir_bios++;
1108 		uiop->uio_offset = bio->bio_offset;
1109 		if (nmp->nm_flag & NFSMNT_RDIRPLUS) {
1110 			error = nfs_readdirplusrpc_uio(vp, uiop);
1111 			if (error == NFSERR_NOTSUPP)
1112 				nmp->nm_flag &= ~NFSMNT_RDIRPLUS;
1113 		}
1114 		if ((nmp->nm_flag & NFSMNT_RDIRPLUS) == 0)
1115 			error = nfs_readdirrpc_uio(vp, uiop);
1116 		/*
1117 		 * end-of-directory sets B_INVAL but does not generate an
1118 		 * error.
1119 		 */
1120 		if (error == 0 && uiop->uio_resid == bp->b_bcount)
1121 			bp->b_flags |= B_INVAL;
1122 		break;
1123 	    default:
1124 		kprintf("nfs_doio:  type %x unexpected\n",vp->v_type);
1125 		break;
1126 	    };
1127 	    if (error) {
1128 		bp->b_flags |= B_ERROR;
1129 		bp->b_error = error;
1130 	    }
1131 	    bp->b_resid = uiop->uio_resid;
1132 	} else {
1133 	    /*
1134 	     * If we only need to commit, try to commit.
1135 	     *
1136 	     * NOTE: The I/O has already been staged for the write and
1137 	     *	     its pages busied, so b_dirtyoff/end is valid.
1138 	     */
1139 	    KKASSERT(bp->b_cmd == BUF_CMD_WRITE);
1140 	    if (bp->b_flags & B_NEEDCOMMIT) {
1141 		    int retv;
1142 		    off_t off;
1143 
1144 		    off = bio->bio_offset + bp->b_dirtyoff;
1145 		    retv = nfs_commitrpc_uio(vp, off,
1146 					     bp->b_dirtyend - bp->b_dirtyoff,
1147 					     td);
1148 		    if (retv == 0) {
1149 			    bp->b_dirtyoff = bp->b_dirtyend = 0;
1150 			    bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1151 			    bp->b_resid = 0;
1152 			    biodone(bio);
1153 			    return(0);
1154 		    }
1155 		    if (retv == NFSERR_STALEWRITEVERF) {
1156 			    nfs_clearcommit(vp->v_mount);
1157 		    }
1158 	    }
1159 
1160 	    /*
1161 	     * Setup for actual write
1162 	     */
1163 	    if (bio->bio_offset + bp->b_dirtyend > np->n_size)
1164 		bp->b_dirtyend = np->n_size - bio->bio_offset;
1165 
1166 	    if (bp->b_dirtyend > bp->b_dirtyoff) {
1167 		io.iov_len = uiop->uio_resid = bp->b_dirtyend
1168 		    - bp->b_dirtyoff;
1169 		uiop->uio_offset = bio->bio_offset + bp->b_dirtyoff;
1170 		io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
1171 		uiop->uio_rw = UIO_WRITE;
1172 		nfsstats.write_bios++;
1173 
1174 		if ((bp->b_flags & (B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == 0)
1175 		    iomode = NFSV3WRITE_UNSTABLE;
1176 		else
1177 		    iomode = NFSV3WRITE_FILESYNC;
1178 
1179 		must_commit = 0;
1180 		error = nfs_writerpc_uio(vp, uiop, &iomode, &must_commit);
1181 
1182 		/*
1183 		 * We no longer try to use kern/vfs_bio's cluster code to
1184 		 * cluster commits, so B_CLUSTEROK is no longer set with
1185 		 * B_NEEDCOMMIT.  The problem is that a vfs_busy_pages()
1186 		 * may have to clear B_NEEDCOMMIT if it finds underlying
1187 		 * pages have been redirtied through a memory mapping
1188 		 * and doing this on a clustered bp will probably cause
1189 		 * a panic, plus the flag in the underlying NFS bufs
1190 		 * making up the cluster bp will not be properly cleared.
1191 		 */
1192 		if (!error && iomode == NFSV3WRITE_UNSTABLE) {
1193 		    bp->b_flags |= B_NEEDCOMMIT;
1194 #if 0
1195 		    /* XXX do not enable commit clustering */
1196 		    if (bp->b_dirtyoff == 0
1197 			&& bp->b_dirtyend == bp->b_bcount)
1198 			bp->b_flags |= B_CLUSTEROK;
1199 #endif
1200 		} else {
1201 		    bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1202 		}
1203 
1204 		/*
1205 		 * For an interrupted write, the buffer is still valid
1206 		 * and the write hasn't been pushed to the server yet,
1207 		 * so we can't set B_ERROR and report the interruption
1208 		 * by setting B_EINTR. For the async case, B_EINTR
1209 		 * is not relevant, so the rpc attempt is essentially
1210 		 * a noop.  For the case of a V3 write rpc not being
1211 		 * committed to stable storage, the block is still
1212 		 * dirty and requires either a commit rpc or another
1213 		 * write rpc with iomode == NFSV3WRITE_FILESYNC before
1214 		 * the block is reused. This is indicated by setting
1215 		 * the B_DELWRI and B_NEEDCOMMIT flags.
1216 		 *
1217 		 * If the buffer is marked B_PAGING, it does not reside on
1218 		 * the vp's paging queues so we cannot call bdirty().  The
1219 		 * bp in this case is not an NFS cache block so we should
1220 		 * be safe. XXX
1221 		 */
1222     		if (error == EINTR
1223 		    || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
1224 			crit_enter();
1225 			bp->b_flags &= ~(B_INVAL|B_NOCACHE);
1226 			if ((bp->b_flags & B_PAGING) == 0)
1227 			    bdirty(bp);
1228 			if (error)
1229 			    bp->b_flags |= B_EINTR;
1230 			crit_exit();
1231 	    	} else {
1232 		    if (error) {
1233 			bp->b_flags |= B_ERROR;
1234 			bp->b_error = np->n_error = error;
1235 			np->n_flag |= NWRITEERR;
1236 		    }
1237 		    bp->b_dirtyoff = bp->b_dirtyend = 0;
1238 		}
1239 		if (must_commit)
1240 		    nfs_clearcommit(vp->v_mount);
1241 		bp->b_resid = uiop->uio_resid;
1242 	    } else {
1243 		bp->b_resid = 0;
1244 	    }
1245 	}
1246 
1247 	/*
1248 	 * I/O was run synchronously, biodone() it and calculate the
1249 	 * error to return.
1250 	 */
1251 	biodone(bio);
1252 	KKASSERT(bp->b_cmd == BUF_CMD_DONE);
1253 	if (bp->b_flags & B_EINTR)
1254 		return (EINTR);
1255 	if (bp->b_flags & B_ERROR)
1256 		return (bp->b_error ? bp->b_error : EIO);
1257 	return (0);
1258 }
1259 
1260 /*
1261  * Handle all truncation, write-extend, and ftruncate()-extend operations
1262  * on the NFS lcient side.
1263  *
1264  * We use the new API in kern/vfs_vm.c to perform these operations in a
1265  * VM-friendly way.  With this API VM pages are properly zerod and pages
1266  * still mapped into the buffer straddling EOF are not invalidated.
1267  */
1268 int
1269 nfs_meta_setsize(struct vnode *vp, struct thread *td, off_t nsize, int trivial)
1270 {
1271 	struct nfsnode *np = VTONFS(vp);
1272 	off_t osize;
1273 	int biosize = vp->v_mount->mnt_stat.f_iosize;
1274 	int error;
1275 
1276 	osize = np->n_size;
1277 	np->n_size = nsize;
1278 
1279 	if (nsize < osize) {
1280 		error = nvtruncbuf(vp, nsize, biosize, -1);
1281 	} else {
1282 		error = nvextendbuf(vp, osize, nsize,
1283 				    biosize, biosize, -1, -1,
1284 				    trivial);
1285 	}
1286 	return(error);
1287 }
1288 
1289 /*
1290  * Synchronous completion for nfs_doio.  Call bpdone() with elseit=FALSE.
1291  * Caller is responsible for brelse()'ing the bp.
1292  */
1293 static void
1294 nfsiodone_sync(struct bio *bio)
1295 {
1296 	bio->bio_flags = 0;
1297 	bpdone(bio->bio_buf, 0);
1298 }
1299 
1300 /*
1301  * nfs read rpc - BIO version
1302  */
1303 void
1304 nfs_readrpc_bio(struct vnode *vp, struct bio *bio)
1305 {
1306 	struct buf *bp = bio->bio_buf;
1307 	u_int32_t *tl;
1308 	struct nfsmount *nmp;
1309 	int error = 0, len, tsiz;
1310 	struct nfsm_info *info;
1311 
1312 	info = kmalloc(sizeof(*info), M_NFSREQ, M_WAITOK);
1313 	info->mrep = NULL;
1314 	info->v3 = NFS_ISV3(vp);
1315 
1316 	nmp = VFSTONFS(vp->v_mount);
1317 	tsiz = bp->b_bcount;
1318 	KKASSERT(tsiz <= nmp->nm_rsize);
1319 	if (bio->bio_offset + tsiz > nmp->nm_maxfilesize) {
1320 		error = EFBIG;
1321 		goto nfsmout;
1322 	}
1323 	nfsstats.rpccnt[NFSPROC_READ]++;
1324 	len = tsiz;
1325 	nfsm_reqhead(info, vp, NFSPROC_READ,
1326 		     NFSX_FH(info->v3) + NFSX_UNSIGNED * 3);
1327 	ERROROUT(nfsm_fhtom(info, vp));
1328 	tl = nfsm_build(info, NFSX_UNSIGNED * 3);
1329 	if (info->v3) {
1330 		txdr_hyper(bio->bio_offset, tl);
1331 		*(tl + 2) = txdr_unsigned(len);
1332 	} else {
1333 		*tl++ = txdr_unsigned(bio->bio_offset);
1334 		*tl++ = txdr_unsigned(len);
1335 		*tl = 0;
1336 	}
1337 	info->bio = bio;
1338 	info->done = nfs_readrpc_bio_done;
1339 	nfsm_request_bio(info, vp, NFSPROC_READ, NULL,
1340 			 nfs_vpcred(vp, ND_READ));
1341 	return;
1342 nfsmout:
1343 	kfree(info, M_NFSREQ);
1344 	bp->b_error = error;
1345 	bp->b_flags |= B_ERROR;
1346 	biodone(bio);
1347 }
1348 
1349 static void
1350 nfs_readrpc_bio_done(nfsm_info_t info)
1351 {
1352 	struct nfsmount *nmp = VFSTONFS(info->vp->v_mount);
1353 	struct bio *bio = info->bio;
1354 	struct buf *bp = bio->bio_buf;
1355 	u_int32_t *tl;
1356 	int attrflag;
1357 	int retlen;
1358 	int eof;
1359 	int error = 0;
1360 
1361 	KKASSERT(info->state == NFSM_STATE_DONE);
1362 
1363 	get_mplock();
1364 
1365 	if (info->v3) {
1366 		ERROROUT(nfsm_postop_attr(info, info->vp, &attrflag,
1367 					 NFS_LATTR_NOSHRINK));
1368 		NULLOUT(tl = nfsm_dissect(info, 2 * NFSX_UNSIGNED));
1369 		eof = fxdr_unsigned(int, *(tl + 1));
1370 	} else {
1371 		ERROROUT(nfsm_loadattr(info, info->vp, NULL));
1372 		eof = 0;
1373 	}
1374 	NEGATIVEOUT(retlen = nfsm_strsiz(info, nmp->nm_rsize));
1375 	ERROROUT(nfsm_mtobio(info, bio, retlen));
1376 	m_freem(info->mrep);
1377 	info->mrep = NULL;
1378 
1379 	/*
1380 	 * No error occured, if retlen is less then bcount and no EOF
1381 	 * and NFSv3 a zero-fill short read occured.
1382 	 *
1383 	 * For NFSv2 a short-read indicates EOF.
1384 	 */
1385 	if (retlen < bp->b_bcount && info->v3 && eof == 0) {
1386 		bzero(bp->b_data + retlen, bp->b_bcount - retlen);
1387 		retlen = bp->b_bcount;
1388 	}
1389 
1390 	/*
1391 	 * If we hit an EOF we still zero-fill, but return the expected
1392 	 * b_resid anyway.  This should normally not occur since async
1393 	 * BIOs are not used for read-before-write case.  Races against
1394 	 * the server can cause it though and we don't want to leave
1395 	 * garbage in the buffer.
1396 	 */
1397 	if (retlen < bp->b_bcount) {
1398 		bzero(bp->b_data + retlen, bp->b_bcount - retlen);
1399 	}
1400 	bp->b_resid = 0;
1401 	/* bp->b_resid = bp->b_bcount - retlen; */
1402 nfsmout:
1403 	rel_mplock();
1404 	kfree(info, M_NFSREQ);
1405 	if (error) {
1406 		bp->b_error = error;
1407 		bp->b_flags |= B_ERROR;
1408 	}
1409 	biodone(bio);
1410 }
1411 
1412 /*
1413  * nfs write call - BIO version
1414  *
1415  * NOTE: Caller has already busied the I/O.
1416  */
1417 void
1418 nfs_writerpc_bio(struct vnode *vp, struct bio *bio)
1419 {
1420 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
1421 	struct nfsnode *np = VTONFS(vp);
1422 	struct buf *bp = bio->bio_buf;
1423 	u_int32_t *tl;
1424 	int len;
1425 	int iomode;
1426 	int error = 0;
1427 	struct nfsm_info *info;
1428 	off_t offset;
1429 
1430 	/*
1431 	 * Setup for actual write.  Just clean up the bio if there
1432 	 * is nothing to do.  b_dirtyoff/end have already been staged
1433 	 * by the bp's pages getting busied.
1434 	 */
1435 	if (bio->bio_offset + bp->b_dirtyend > np->n_size)
1436 		bp->b_dirtyend = np->n_size - bio->bio_offset;
1437 
1438 	if (bp->b_dirtyend <= bp->b_dirtyoff) {
1439 		bp->b_resid = 0;
1440 		biodone(bio);
1441 		return;
1442 	}
1443 	len = bp->b_dirtyend - bp->b_dirtyoff;
1444 	offset = bio->bio_offset + bp->b_dirtyoff;
1445 	if (offset + len > nmp->nm_maxfilesize) {
1446 		bp->b_flags |= B_ERROR;
1447 		bp->b_error = EFBIG;
1448 		biodone(bio);
1449 		return;
1450 	}
1451 	bp->b_resid = len;
1452 	nfsstats.write_bios++;
1453 
1454 	info = kmalloc(sizeof(*info), M_NFSREQ, M_WAITOK);
1455 	info->mrep = NULL;
1456 	info->v3 = NFS_ISV3(vp);
1457 	info->info_writerpc.must_commit = 0;
1458 	if ((bp->b_flags & (B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == 0)
1459 		iomode = NFSV3WRITE_UNSTABLE;
1460 	else
1461 		iomode = NFSV3WRITE_FILESYNC;
1462 
1463 	KKASSERT(len <= nmp->nm_wsize);
1464 
1465 	nfsstats.rpccnt[NFSPROC_WRITE]++;
1466 	nfsm_reqhead(info, vp, NFSPROC_WRITE,
1467 		     NFSX_FH(info->v3) + 5 * NFSX_UNSIGNED + nfsm_rndup(len));
1468 	ERROROUT(nfsm_fhtom(info, vp));
1469 	if (info->v3) {
1470 		tl = nfsm_build(info, 5 * NFSX_UNSIGNED);
1471 		txdr_hyper(offset, tl);
1472 		tl += 2;
1473 		*tl++ = txdr_unsigned(len);
1474 		*tl++ = txdr_unsigned(iomode);
1475 		*tl = txdr_unsigned(len);
1476 	} else {
1477 		u_int32_t x;
1478 
1479 		tl = nfsm_build(info, 4 * NFSX_UNSIGNED);
1480 		/* Set both "begin" and "current" to non-garbage. */
1481 		x = txdr_unsigned((u_int32_t)offset);
1482 		*tl++ = x;	/* "begin offset" */
1483 		*tl++ = x;	/* "current offset" */
1484 		x = txdr_unsigned(len);
1485 		*tl++ = x;	/* total to this offset */
1486 		*tl = x;	/* size of this write */
1487 	}
1488 	ERROROUT(nfsm_biotom(info, bio, bp->b_dirtyoff, len));
1489 	info->bio = bio;
1490 	info->done = nfs_writerpc_bio_done;
1491 	nfsm_request_bio(info, vp, NFSPROC_WRITE, NULL,
1492 			 nfs_vpcred(vp, ND_WRITE));
1493 	return;
1494 nfsmout:
1495 	kfree(info, M_NFSREQ);
1496 	bp->b_error = error;
1497 	bp->b_flags |= B_ERROR;
1498 	biodone(bio);
1499 }
1500 
1501 static void
1502 nfs_writerpc_bio_done(nfsm_info_t info)
1503 {
1504 	struct nfsmount *nmp = VFSTONFS(info->vp->v_mount);
1505 	struct nfsnode *np = VTONFS(info->vp);
1506 	struct bio *bio = info->bio;
1507 	struct buf *bp = bio->bio_buf;
1508 	int wccflag = NFSV3_WCCRATTR;
1509 	int iomode = NFSV3WRITE_FILESYNC;
1510 	int commit;
1511 	int rlen;
1512 	int error;
1513 	int len = bp->b_resid;	/* b_resid was set to shortened length */
1514 	u_int32_t *tl;
1515 
1516 	get_mplock();
1517 
1518 	if (info->v3) {
1519 		/*
1520 		 * The write RPC returns a before and after mtime.  The
1521 		 * nfsm_wcc_data() macro checks the before n_mtime
1522 		 * against the before time and stores the after time
1523 		 * in the nfsnode's cached vattr and n_mtime field.
1524 		 * The NRMODIFIED bit will be set if the before
1525 		 * time did not match the original mtime.
1526 		 */
1527 		wccflag = NFSV3_WCCCHK;
1528 		ERROROUT(nfsm_wcc_data(info, info->vp, &wccflag));
1529 		if (error == 0) {
1530 			NULLOUT(tl = nfsm_dissect(info, 2 * NFSX_UNSIGNED + NFSX_V3WRITEVERF));
1531 			rlen = fxdr_unsigned(int, *tl++);
1532 			if (rlen == 0) {
1533 				error = NFSERR_IO;
1534 				m_freem(info->mrep);
1535 				info->mrep = NULL;
1536 				goto nfsmout;
1537 			} else if (rlen < len) {
1538 #if 0
1539 				/*
1540 				 * XXX what do we do here?
1541 				 */
1542 				backup = len - rlen;
1543 				uiop->uio_iov->iov_base = (char *)uiop->uio_iov->iov_base - backup;
1544 				uiop->uio_iov->iov_len += backup;
1545 				uiop->uio_offset -= backup;
1546 				uiop->uio_resid += backup;
1547 				len = rlen;
1548 #endif
1549 			}
1550 			commit = fxdr_unsigned(int, *tl++);
1551 
1552 			/*
1553 			 * Return the lowest committment level
1554 			 * obtained by any of the RPCs.
1555 			 */
1556 			if (iomode == NFSV3WRITE_FILESYNC)
1557 				iomode = commit;
1558 			else if (iomode == NFSV3WRITE_DATASYNC &&
1559 				commit == NFSV3WRITE_UNSTABLE)
1560 				iomode = commit;
1561 			if ((nmp->nm_state & NFSSTA_HASWRITEVERF) == 0){
1562 			    bcopy(tl, (caddr_t)nmp->nm_verf, NFSX_V3WRITEVERF);
1563 			    nmp->nm_state |= NFSSTA_HASWRITEVERF;
1564 			} else if (bcmp(tl, nmp->nm_verf, NFSX_V3WRITEVERF)) {
1565 			    info->info_writerpc.must_commit = 1;
1566 			    bcopy(tl, (caddr_t)nmp->nm_verf, NFSX_V3WRITEVERF);
1567 			}
1568 		}
1569 	} else {
1570 		ERROROUT(nfsm_loadattr(info, info->vp, NULL));
1571 	}
1572 	m_freem(info->mrep);
1573 	info->mrep = NULL;
1574 	len = 0;
1575 nfsmout:
1576 	if (info->vp->v_mount->mnt_flag & MNT_ASYNC)
1577 		iomode = NFSV3WRITE_FILESYNC;
1578 	bp->b_resid = len;
1579 
1580 	/*
1581 	 * End of RPC.  Now clean up the bp.
1582 	 *
1583 	 * We no longer enable write clustering for commit operations,
1584 	 * See around line 1157 for a more detailed comment.
1585 	 */
1586 	if (!error && iomode == NFSV3WRITE_UNSTABLE) {
1587 		bp->b_flags |= B_NEEDCOMMIT;
1588 #if 0
1589 		/* XXX do not enable commit clustering */
1590 		if (bp->b_dirtyoff == 0 && bp->b_dirtyend == bp->b_bcount)
1591 			bp->b_flags |= B_CLUSTEROK;
1592 #endif
1593 	} else {
1594 		bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1595 	}
1596 
1597 	/*
1598 	 * For an interrupted write, the buffer is still valid
1599 	 * and the write hasn't been pushed to the server yet,
1600 	 * so we can't set B_ERROR and report the interruption
1601 	 * by setting B_EINTR. For the async case, B_EINTR
1602 	 * is not relevant, so the rpc attempt is essentially
1603 	 * a noop.  For the case of a V3 write rpc not being
1604 	 * committed to stable storage, the block is still
1605 	 * dirty and requires either a commit rpc or another
1606 	 * write rpc with iomode == NFSV3WRITE_FILESYNC before
1607 	 * the block is reused. This is indicated by setting
1608 	 * the B_DELWRI and B_NEEDCOMMIT flags.
1609 	 *
1610 	 * If the buffer is marked B_PAGING, it does not reside on
1611 	 * the vp's paging queues so we cannot call bdirty().  The
1612 	 * bp in this case is not an NFS cache block so we should
1613 	 * be safe. XXX
1614 	 */
1615 	if (error == EINTR || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
1616 		crit_enter();
1617 		bp->b_flags &= ~(B_INVAL|B_NOCACHE);
1618 		if ((bp->b_flags & B_PAGING) == 0)
1619 			bdirty(bp);
1620 		if (error)
1621 			bp->b_flags |= B_EINTR;
1622 		crit_exit();
1623 	} else {
1624 		if (error) {
1625 			bp->b_flags |= B_ERROR;
1626 			bp->b_error = np->n_error = error;
1627 			np->n_flag |= NWRITEERR;
1628 		}
1629 		bp->b_dirtyoff = bp->b_dirtyend = 0;
1630 	}
1631 	if (info->info_writerpc.must_commit)
1632 		nfs_clearcommit(info->vp->v_mount);
1633 	rel_mplock();
1634 	kfree(info, M_NFSREQ);
1635 	if (error) {
1636 		bp->b_flags |= B_ERROR;
1637 		bp->b_error = error;
1638 	}
1639 	biodone(bio);
1640 }
1641 
1642 /*
1643  * Nfs Version 3 commit rpc - BIO version
1644  *
1645  * This function issues the commit rpc and will chain to a write
1646  * rpc if necessary.
1647  */
1648 void
1649 nfs_commitrpc_bio(struct vnode *vp, struct bio *bio)
1650 {
1651 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
1652 	struct buf *bp = bio->bio_buf;
1653 	struct nfsm_info *info;
1654 	int error = 0;
1655 	u_int32_t *tl;
1656 
1657 	if ((nmp->nm_state & NFSSTA_HASWRITEVERF) == 0) {
1658 		bp->b_dirtyoff = bp->b_dirtyend = 0;
1659 		bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1660 		bp->b_resid = 0;
1661 		biodone(bio);
1662 		return;
1663 	}
1664 
1665 	info = kmalloc(sizeof(*info), M_NFSREQ, M_WAITOK);
1666 	info->mrep = NULL;
1667 	info->v3 = 1;
1668 
1669 	nfsstats.rpccnt[NFSPROC_COMMIT]++;
1670 	nfsm_reqhead(info, vp, NFSPROC_COMMIT, NFSX_FH(1));
1671 	ERROROUT(nfsm_fhtom(info, vp));
1672 	tl = nfsm_build(info, 3 * NFSX_UNSIGNED);
1673 	txdr_hyper(bio->bio_offset + bp->b_dirtyoff, tl);
1674 	tl += 2;
1675 	*tl = txdr_unsigned(bp->b_dirtyend - bp->b_dirtyoff);
1676 	info->bio = bio;
1677 	info->done = nfs_commitrpc_bio_done;
1678 	nfsm_request_bio(info, vp, NFSPROC_COMMIT, NULL,
1679 			 nfs_vpcred(vp, ND_WRITE));
1680 	return;
1681 nfsmout:
1682 	/*
1683 	 * Chain to write RPC on (early) error
1684 	 */
1685 	kfree(info, M_NFSREQ);
1686 	nfs_writerpc_bio(vp, bio);
1687 }
1688 
1689 static void
1690 nfs_commitrpc_bio_done(nfsm_info_t info)
1691 {
1692 	struct nfsmount *nmp = VFSTONFS(info->vp->v_mount);
1693 	struct bio *bio = info->bio;
1694 	struct buf *bp = bio->bio_buf;
1695 	u_int32_t *tl;
1696 	int wccflag = NFSV3_WCCRATTR;
1697 	int error = 0;
1698 
1699 	get_mplock();
1700 
1701 	ERROROUT(nfsm_wcc_data(info, info->vp, &wccflag));
1702 	if (error == 0) {
1703 		NULLOUT(tl = nfsm_dissect(info, NFSX_V3WRITEVERF));
1704 		if (bcmp(nmp->nm_verf, tl, NFSX_V3WRITEVERF)) {
1705 			bcopy(tl, nmp->nm_verf, NFSX_V3WRITEVERF);
1706 			error = NFSERR_STALEWRITEVERF;
1707 		}
1708 	}
1709 	m_freem(info->mrep);
1710 	info->mrep = NULL;
1711 
1712 	/*
1713 	 * On completion we must chain to a write bio if an
1714 	 * error occurred.
1715 	 */
1716 nfsmout:
1717 	kfree(info, M_NFSREQ);
1718 	if (error == 0) {
1719 		bp->b_dirtyoff = bp->b_dirtyend = 0;
1720 		bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1721 		bp->b_resid = 0;
1722 		biodone(bio);
1723 	} else {
1724 		nfs_writerpc_bio(info->vp, bio);
1725 	}
1726 	rel_mplock();
1727 }
1728 
1729