xref: /dragonfly/sys/vfs/nfs/nfs_bio.c (revision a68e0df0)
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 <vm/vm_page2.h>
63 
64 #include "rpcv2.h"
65 #include "nfsproto.h"
66 #include "nfs.h"
67 #include "nfsmount.h"
68 #include "nfsnode.h"
69 #include "xdr_subs.h"
70 #include "nfsm_subs.h"
71 
72 
73 static struct buf *nfs_getcacheblk(struct vnode *vp, off_t loffset,
74 				   int size, struct thread *td);
75 static int nfs_check_dirent(struct nfs_dirent *dp, int maxlen);
76 static void nfsiodone_sync(struct bio *bio);
77 static void nfs_readrpc_bio_done(nfsm_info_t info);
78 static void nfs_writerpc_bio_done(nfsm_info_t info);
79 static void nfs_commitrpc_bio_done(nfsm_info_t info);
80 
81 /*
82  * Vnode op for read using bio
83  */
84 int
85 nfs_bioread(struct vnode *vp, struct uio *uio, int ioflag)
86 {
87 	struct nfsnode *np = VTONFS(vp);
88 	int biosize, i;
89 	struct buf *bp, *rabp;
90 	struct vattr vattr;
91 	struct thread *td;
92 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
93 	off_t lbn, rabn;
94 	off_t raoffset;
95 	off_t loffset;
96 	int seqcount;
97 	int nra, error = 0;
98 	int boff = 0;
99 	size_t n;
100 
101 #ifdef DIAGNOSTIC
102 	if (uio->uio_rw != UIO_READ)
103 		panic("nfs_read mode");
104 #endif
105 	if (uio->uio_resid == 0)
106 		return (0);
107 	if (uio->uio_offset < 0)	/* XXX VDIR cookies can be negative */
108 		return (EINVAL);
109 	td = uio->uio_td;
110 
111 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
112 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
113 		(void)nfs_fsinfo(nmp, vp, td);
114 	if (vp->v_type != VDIR &&
115 	    (uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
116 		return (EFBIG);
117 	biosize = vp->v_mount->mnt_stat.f_iosize;
118 	seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
119 
120 	/*
121 	 * For nfs, cache consistency can only be maintained approximately.
122 	 * Although RFC1094 does not specify the criteria, the following is
123 	 * believed to be compatible with the reference port.
124 	 *
125 	 * NFS:		If local changes have been made and this is a
126 	 *		directory, the directory must be invalidated and
127 	 *		the attribute cache must be cleared.
128 	 *
129 	 *		GETATTR is called to synchronize the file size.
130 	 *
131 	 *		If remote changes are detected local data is flushed
132 	 *		and the cache is invalidated.
133 	 *
134 	 *		NOTE: In the normal case the attribute cache is not
135 	 *		cleared which means GETATTR may use cached data and
136 	 *		not immediately detect changes made on the server.
137 	 */
138 	if ((np->n_flag & NLMODIFIED) && vp->v_type == VDIR) {
139 		nfs_invaldir(vp);
140 		error = nfs_vinvalbuf(vp, V_SAVE, 1);
141 		if (error)
142 			return (error);
143 		np->n_attrstamp = 0;
144 	}
145 	error = VOP_GETATTR(vp, &vattr);
146 	if (error)
147 		return (error);
148 
149 	/*
150 	 * This can deadlock getpages/putpages for regular
151 	 * files.  Only do it for directories.
152 	 */
153 	if (np->n_flag & NRMODIFIED) {
154 		if (vp->v_type == VDIR) {
155 			nfs_invaldir(vp);
156 			error = nfs_vinvalbuf(vp, V_SAVE, 1);
157 			if (error)
158 				return (error);
159 			np->n_flag &= ~NRMODIFIED;
160 		}
161 	}
162 
163 	/*
164 	 * Loop until uio exhausted or we hit EOF
165 	 */
166 	do {
167 	    bp = NULL;
168 
169 	    switch (vp->v_type) {
170 	    case VREG:
171 		nfsstats.biocache_reads++;
172 		lbn = uio->uio_offset / biosize;
173 		boff = uio->uio_offset & (biosize - 1);
174 		loffset = (off_t)lbn * biosize;
175 
176 		/*
177 		 * Start the read ahead(s), as required.
178 		 */
179 		if (nmp->nm_readahead > 0 && nfs_asyncok(nmp)) {
180 		    for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
181 			(off_t)(lbn + 1 + nra) * biosize < np->n_size; nra++) {
182 			rabn = lbn + 1 + nra;
183 			raoffset = (off_t)rabn * biosize;
184 			if (findblk(vp, raoffset, FINDBLK_TEST) == NULL) {
185 			    rabp = nfs_getcacheblk(vp, raoffset, biosize, td);
186 			    if (!rabp)
187 				return (EINTR);
188 			    if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
189 				rabp->b_cmd = BUF_CMD_READ;
190 				vfs_busy_pages(vp, rabp);
191 				nfs_asyncio(vp, &rabp->b_bio2);
192 			    } else {
193 				brelse(rabp);
194 			    }
195 			}
196 		    }
197 		}
198 
199 		/*
200 		 * Obtain the buffer cache block.  Figure out the buffer size
201 		 * when we are at EOF.  If we are modifying the size of the
202 		 * buffer based on an EOF condition we need to hold
203 		 * nfs_rslock() through obtaining the buffer to prevent
204 		 * a potential writer-appender from messing with n_size.
205 		 * Otherwise we may accidently truncate the buffer and
206 		 * lose dirty data.
207 		 *
208 		 * Note that bcount is *not* DEV_BSIZE aligned.
209 		 */
210 		if (loffset + boff >= np->n_size) {
211 			n = 0;
212 			break;
213 		}
214 		bp = nfs_getcacheblk(vp, loffset, biosize, td);
215 
216 		if (bp == NULL)
217 			return (EINTR);
218 
219 		/*
220 		 * If B_CACHE is not set, we must issue the read.  If this
221 		 * fails, we return an error.
222 		 */
223 		if ((bp->b_flags & B_CACHE) == 0) {
224 			bp->b_cmd = BUF_CMD_READ;
225 			bp->b_bio2.bio_done = nfsiodone_sync;
226 			bp->b_bio2.bio_flags |= BIO_SYNC;
227 			vfs_busy_pages(vp, bp);
228 			error = nfs_doio(vp, &bp->b_bio2, td);
229 			if (error) {
230 				brelse(bp);
231 				return (error);
232 			}
233 		}
234 
235 		/*
236 		 * on is the offset into the current bp.  Figure out how many
237 		 * bytes we can copy out of the bp.  Note that bcount is
238 		 * NOT DEV_BSIZE aligned.
239 		 *
240 		 * Then figure out how many bytes we can copy into the uio.
241 		 */
242 		n = biosize - boff;
243 		if (n > uio->uio_resid)
244 			n = uio->uio_resid;
245 		if (loffset + boff + n > np->n_size)
246 			n = np->n_size - loffset - boff;
247 		break;
248 	    case VLNK:
249 		biosize = min(NFS_MAXPATHLEN, np->n_size);
250 		nfsstats.biocache_readlinks++;
251 		bp = nfs_getcacheblk(vp, (off_t)0, biosize, td);
252 		if (bp == NULL)
253 			return (EINTR);
254 		if ((bp->b_flags & B_CACHE) == 0) {
255 			bp->b_cmd = BUF_CMD_READ;
256 			bp->b_bio2.bio_done = nfsiodone_sync;
257 			bp->b_bio2.bio_flags |= BIO_SYNC;
258 			vfs_busy_pages(vp, bp);
259 			error = nfs_doio(vp, &bp->b_bio2, td);
260 			if (error) {
261 				bp->b_flags |= B_ERROR | B_INVAL;
262 				brelse(bp);
263 				return (error);
264 			}
265 		}
266 		n = szmin(uio->uio_resid, (size_t)bp->b_bcount - bp->b_resid);
267 		boff = 0;
268 		break;
269 	    case VDIR:
270 		nfsstats.biocache_readdirs++;
271 		if (np->n_direofoffset &&
272 		    uio->uio_offset >= np->n_direofoffset
273 		) {
274 			return (0);
275 		}
276 		lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
277 		boff = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
278 		loffset = uio->uio_offset - boff;
279 		bp = nfs_getcacheblk(vp, loffset, NFS_DIRBLKSIZ, td);
280 		if (bp == NULL)
281 			return (EINTR);
282 
283 		if ((bp->b_flags & B_CACHE) == 0) {
284 		    bp->b_cmd = BUF_CMD_READ;
285 		    bp->b_bio2.bio_done = nfsiodone_sync;
286 		    bp->b_bio2.bio_flags |= BIO_SYNC;
287 		    vfs_busy_pages(vp, bp);
288 		    error = nfs_doio(vp, &bp->b_bio2, td);
289 		    if (error)
290 			    brelse(bp);
291 		    while (error == NFSERR_BAD_COOKIE) {
292 			kprintf("got bad cookie vp %p bp %p\n", vp, bp);
293 			nfs_invaldir(vp);
294 			error = nfs_vinvalbuf(vp, 0, 1);
295 			/*
296 			 * Yuck! The directory has been modified on the
297 			 * server. The only way to get the block is by
298 			 * reading from the beginning to get all the
299 			 * offset cookies.
300 			 *
301 			 * Leave the last bp intact unless there is an error.
302 			 * Loop back up to the while if the error is another
303 			 * NFSERR_BAD_COOKIE (double yuch!).
304 			 */
305 			for (i = 0; i <= lbn && !error; i++) {
306 			    if (np->n_direofoffset
307 				&& (i * NFS_DIRBLKSIZ) >= np->n_direofoffset)
308 				    return (0);
309 			    bp = nfs_getcacheblk(vp, (off_t)i * NFS_DIRBLKSIZ,
310 						 NFS_DIRBLKSIZ, td);
311 			    if (!bp)
312 				return (EINTR);
313 			    if ((bp->b_flags & B_CACHE) == 0) {
314 				    bp->b_cmd = BUF_CMD_READ;
315 				    bp->b_bio2.bio_done = nfsiodone_sync;
316 				    bp->b_bio2.bio_flags |= BIO_SYNC;
317 				    vfs_busy_pages(vp, bp);
318 				    error = nfs_doio(vp, &bp->b_bio2, td);
319 				    /*
320 				     * no error + B_INVAL == directory EOF,
321 				     * use the block.
322 				     */
323 				    if (error == 0 && (bp->b_flags & B_INVAL))
324 					    break;
325 			    }
326 			    /*
327 			     * An error will throw away the block and the
328 			     * for loop will break out.  If no error and this
329 			     * is not the block we want, we throw away the
330 			     * block and go for the next one via the for loop.
331 			     */
332 			    if (error || i < lbn)
333 				    brelse(bp);
334 			}
335 		    }
336 		    /*
337 		     * The above while is repeated if we hit another cookie
338 		     * error.  If we hit an error and it wasn't a cookie error,
339 		     * we give up.
340 		     */
341 		    if (error)
342 			    return (error);
343 		}
344 
345 		/*
346 		 * If not eof and read aheads are enabled, start one.
347 		 * (You need the current block first, so that you have the
348 		 *  directory offset cookie of the next block.)
349 		 */
350 		if (nmp->nm_readahead > 0 && nfs_asyncok(nmp) &&
351 		    (bp->b_flags & B_INVAL) == 0 &&
352 		    (np->n_direofoffset == 0 ||
353 		    loffset + NFS_DIRBLKSIZ < np->n_direofoffset) &&
354 		    findblk(vp, loffset + NFS_DIRBLKSIZ, FINDBLK_TEST) == NULL
355 		) {
356 			rabp = nfs_getcacheblk(vp, loffset + NFS_DIRBLKSIZ,
357 					       NFS_DIRBLKSIZ, td);
358 			if (rabp) {
359 			    if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
360 				rabp->b_cmd = BUF_CMD_READ;
361 				vfs_busy_pages(vp, rabp);
362 				nfs_asyncio(vp, &rabp->b_bio2);
363 			    } else {
364 				brelse(rabp);
365 			    }
366 			}
367 		}
368 		/*
369 		 * Unlike VREG files, whos buffer size ( bp->b_bcount ) is
370 		 * chopped for the EOF condition, we cannot tell how large
371 		 * NFS directories are going to be until we hit EOF.  So
372 		 * an NFS directory buffer is *not* chopped to its EOF.  Now,
373 		 * it just so happens that b_resid will effectively chop it
374 		 * to EOF.  *BUT* this information is lost if the buffer goes
375 		 * away and is reconstituted into a B_CACHE state ( due to
376 		 * being VMIO ) later.  So we keep track of the directory eof
377 		 * in np->n_direofoffset and chop it off as an extra step
378 		 * right here.
379 		 *
380 		 * NOTE: boff could already be beyond EOF.
381 		 */
382 		if ((size_t)boff > NFS_DIRBLKSIZ - bp->b_resid) {
383 			n = 0;
384 		} else {
385 			n = szmin(uio->uio_resid,
386 				  NFS_DIRBLKSIZ - bp->b_resid - (size_t)boff);
387 		}
388 		if (np->n_direofoffset &&
389 		    n > (size_t)(np->n_direofoffset - uio->uio_offset)) {
390 			n = (size_t)(np->n_direofoffset - uio->uio_offset);
391 		}
392 		break;
393 	    default:
394 		kprintf(" nfs_bioread: type %x unexpected\n",vp->v_type);
395 		n = 0;
396 		break;
397 	    };
398 
399 	    switch (vp->v_type) {
400 	    case VREG:
401 		if (n > 0)
402 		    error = uiomove(bp->b_data + boff, n, uio);
403 		break;
404 	    case VLNK:
405 		if (n > 0)
406 		    error = uiomove(bp->b_data + boff, n, uio);
407 		n = 0;
408 		break;
409 	    case VDIR:
410 		if (n > 0) {
411 		    off_t old_off = uio->uio_offset;
412 		    caddr_t cpos, epos;
413 		    struct nfs_dirent *dp;
414 
415 		    /*
416 		     * We are casting cpos to nfs_dirent, it must be
417 		     * int-aligned.
418 		     */
419 		    if (boff & 3) {
420 			error = EINVAL;
421 			break;
422 		    }
423 
424 		    cpos = bp->b_data + boff;
425 		    epos = bp->b_data + boff + n;
426 		    while (cpos < epos && error == 0 && uio->uio_resid > 0) {
427 			    dp = (struct nfs_dirent *)cpos;
428 			    error = nfs_check_dirent(dp, (int)(epos - cpos));
429 			    if (error)
430 				    break;
431 			    if (vop_write_dirent(&error, uio, dp->nfs_ino,
432 				dp->nfs_type, dp->nfs_namlen, dp->nfs_name)) {
433 				    break;
434 			    }
435 			    cpos += dp->nfs_reclen;
436 		    }
437 		    n = 0;
438 		    if (error == 0) {
439 			    uio->uio_offset = old_off + cpos -
440 					      bp->b_data - boff;
441 		    }
442 		}
443 		break;
444 	    default:
445 		kprintf(" nfs_bioread: type %x unexpected\n",vp->v_type);
446 	    }
447 	    if (bp)
448 		    brelse(bp);
449 	} while (error == 0 && uio->uio_resid > 0 && n > 0);
450 	return (error);
451 }
452 
453 /*
454  * Userland can supply any 'seek' offset when reading a NFS directory.
455  * Validate the structure so we don't panic the kernel.  Note that
456  * the element name is nul terminated and the nul is not included
457  * in nfs_namlen.
458  */
459 static
460 int
461 nfs_check_dirent(struct nfs_dirent *dp, int maxlen)
462 {
463 	int nfs_name_off = offsetof(struct nfs_dirent, nfs_name[0]);
464 
465 	if (nfs_name_off >= maxlen)
466 		return (EINVAL);
467 	if (dp->nfs_reclen < nfs_name_off || dp->nfs_reclen > maxlen)
468 		return (EINVAL);
469 	if (nfs_name_off + dp->nfs_namlen >= dp->nfs_reclen)
470 		return (EINVAL);
471 	if (dp->nfs_reclen & 3)
472 		return (EINVAL);
473 	return (0);
474 }
475 
476 /*
477  * Vnode op for write using bio
478  *
479  * nfs_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
480  *	     struct ucred *a_cred)
481  */
482 int
483 nfs_write(struct vop_write_args *ap)
484 {
485 	struct uio *uio = ap->a_uio;
486 	struct thread *td = uio->uio_td;
487 	struct vnode *vp = ap->a_vp;
488 	struct nfsnode *np = VTONFS(vp);
489 	int ioflag = ap->a_ioflag;
490 	struct buf *bp;
491 	struct vattr vattr;
492 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
493 	off_t loffset;
494 	int boff, bytes;
495 	int error = 0;
496 	int haverslock = 0;
497 	int bcount;
498 	int biosize;
499 	int trivial;
500 
501 #ifdef DIAGNOSTIC
502 	if (uio->uio_rw != UIO_WRITE)
503 		panic("nfs_write mode");
504 	if (uio->uio_segflg == UIO_USERSPACE && uio->uio_td != curthread)
505 		panic("nfs_write proc");
506 #endif
507 	if (vp->v_type != VREG)
508 		return (EIO);
509 	if (np->n_flag & NWRITEERR) {
510 		np->n_flag &= ~NWRITEERR;
511 		return (np->n_error);
512 	}
513 	if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
514 	    (nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
515 		(void)nfs_fsinfo(nmp, vp, td);
516 
517 	/*
518 	 * Synchronously flush pending buffers if we are in synchronous
519 	 * mode or if we are appending.
520 	 */
521 	if (ioflag & (IO_APPEND | IO_SYNC)) {
522 		if (np->n_flag & NLMODIFIED) {
523 			np->n_attrstamp = 0;
524 			error = nfs_flush(vp, MNT_WAIT, td, 0);
525 			/* error = nfs_vinvalbuf(vp, V_SAVE, 1); */
526 			if (error)
527 				return (error);
528 		}
529 	}
530 
531 	/*
532 	 * If IO_APPEND then load uio_offset.  We restart here if we cannot
533 	 * get the append lock.
534 	 */
535 restart:
536 	if (ioflag & IO_APPEND) {
537 		np->n_attrstamp = 0;
538 		error = VOP_GETATTR(vp, &vattr);
539 		if (error)
540 			return (error);
541 		uio->uio_offset = np->n_size;
542 	}
543 
544 	if (uio->uio_offset < 0)
545 		return (EINVAL);
546 	if ((uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
547 		return (EFBIG);
548 	if (uio->uio_resid == 0)
549 		return (0);
550 
551 	/*
552 	 * We need to obtain the rslock if we intend to modify np->n_size
553 	 * in order to guarentee the append point with multiple contending
554 	 * writers, to guarentee that no other appenders modify n_size
555 	 * while we are trying to obtain a truncated buffer (i.e. to avoid
556 	 * accidently truncating data written by another appender due to
557 	 * the race), and to ensure that the buffer is populated prior to
558 	 * our extending of the file.  We hold rslock through the entire
559 	 * operation.
560 	 *
561 	 * Note that we do not synchronize the case where someone truncates
562 	 * the file while we are appending to it because attempting to lock
563 	 * this case may deadlock other parts of the system unexpectedly.
564 	 */
565 	if ((ioflag & IO_APPEND) ||
566 	    uio->uio_offset + uio->uio_resid > np->n_size) {
567 		switch(nfs_rslock(np)) {
568 		case ENOLCK:
569 			goto restart;
570 			/* not reached */
571 		case EINTR:
572 		case ERESTART:
573 			return(EINTR);
574 			/* not reached */
575 		default:
576 			break;
577 		}
578 		haverslock = 1;
579 	}
580 
581 	/*
582 	 * Maybe this should be above the vnode op call, but so long as
583 	 * file servers have no limits, i don't think it matters
584 	 */
585 	if (td && td->td_proc && uio->uio_offset + uio->uio_resid >
586 	      td->td_proc->p_rlimit[RLIMIT_FSIZE].rlim_cur) {
587 		lwpsignal(td->td_proc, td->td_lwp, SIGXFSZ);
588 		if (haverslock)
589 			nfs_rsunlock(np);
590 		return (EFBIG);
591 	}
592 
593 	biosize = vp->v_mount->mnt_stat.f_iosize;
594 
595 	do {
596 		nfsstats.biocache_writes++;
597 		boff = uio->uio_offset & (biosize-1);
598 		loffset = uio->uio_offset - boff;
599 		bytes = (int)szmin((unsigned)(biosize - boff), uio->uio_resid);
600 again:
601 		/*
602 		 * Handle direct append and file extension cases, calculate
603 		 * unaligned buffer size.  When extending B_CACHE will be
604 		 * set if possible.  See UIO_NOCOPY note below.
605 		 */
606 		if (uio->uio_offset + bytes > np->n_size) {
607 			np->n_flag |= NLMODIFIED;
608 			trivial = (uio->uio_segflg != UIO_NOCOPY &&
609 				   uio->uio_offset <= np->n_size);
610 			nfs_meta_setsize(vp, td, uio->uio_offset + bytes,
611 					 trivial);
612 		}
613 		bp = nfs_getcacheblk(vp, loffset, biosize, td);
614 		if (bp == NULL) {
615 			error = EINTR;
616 			break;
617 		}
618 
619 		/*
620 		 * Actual bytes in buffer which we care about
621 		 */
622 		if (loffset + biosize < np->n_size)
623 			bcount = biosize;
624 		else
625 			bcount = (int)(np->n_size - loffset);
626 
627 		/*
628 		 * Avoid a read by setting B_CACHE where the data we
629 		 * intend to write covers the entire buffer.  Note
630 		 * that the buffer may have been set to B_CACHE by
631 		 * nfs_meta_setsize() above or otherwise inherited the
632 		 * flag, but if B_CACHE isn't set the buffer may be
633 		 * uninitialized and must be zero'd to accomodate
634 		 * future seek+write's.
635 		 *
636 		 * See the comments in kern/vfs_bio.c's getblk() for
637 		 * more information.
638 		 *
639 		 * When doing a UIO_NOCOPY write the buffer is not
640 		 * overwritten and we cannot just set B_CACHE unconditionally
641 		 * for full-block writes.
642 		 */
643 		if (boff == 0 && bytes == biosize &&
644 		    uio->uio_segflg != UIO_NOCOPY) {
645 			bp->b_flags |= B_CACHE;
646 			bp->b_flags &= ~(B_ERROR | B_INVAL);
647 		}
648 
649 		/*
650 		 * b_resid may be set due to file EOF if we extended out.
651 		 * The NFS bio code will zero the difference anyway so
652 		 * just acknowledged the fact and set b_resid to 0.
653 		 */
654 		if ((bp->b_flags & B_CACHE) == 0) {
655 			bp->b_cmd = BUF_CMD_READ;
656 			bp->b_bio2.bio_done = nfsiodone_sync;
657 			bp->b_bio2.bio_flags |= BIO_SYNC;
658 			vfs_busy_pages(vp, bp);
659 			error = nfs_doio(vp, &bp->b_bio2, td);
660 			if (error) {
661 				brelse(bp);
662 				break;
663 			}
664 			bp->b_resid = 0;
665 		}
666 		np->n_flag |= NLMODIFIED;
667 
668 		/*
669 		 * If dirtyend exceeds file size, chop it down.  This should
670 		 * not normally occur but there is an append race where it
671 		 * might occur XXX, so we log it.
672 		 *
673 		 * If the chopping creates a reverse-indexed or degenerate
674 		 * situation with dirtyoff/end, we 0 both of them.
675 		 */
676 		if (bp->b_dirtyend > bcount) {
677 			kprintf("NFS append race @%08llx:%d\n",
678 			    (long long)bp->b_bio2.bio_offset,
679 			    bp->b_dirtyend - bcount);
680 			bp->b_dirtyend = bcount;
681 		}
682 
683 		if (bp->b_dirtyoff >= bp->b_dirtyend)
684 			bp->b_dirtyoff = bp->b_dirtyend = 0;
685 
686 		/*
687 		 * If the new write will leave a contiguous dirty
688 		 * area, just update the b_dirtyoff and b_dirtyend,
689 		 * otherwise force a write rpc of the old dirty area.
690 		 *
691 		 * While it is possible to merge discontiguous writes due to
692 		 * our having a B_CACHE buffer ( and thus valid read data
693 		 * for the hole), we don't because it could lead to
694 		 * significant cache coherency problems with multiple clients,
695 		 * especially if locking is implemented later on.
696 		 *
697 		 * as an optimization we could theoretically maintain
698 		 * a linked list of discontinuous areas, but we would still
699 		 * have to commit them separately so there isn't much
700 		 * advantage to it except perhaps a bit of asynchronization.
701 		 */
702 		if (bp->b_dirtyend > 0 &&
703 		    (boff > bp->b_dirtyend ||
704 		     (boff + bytes) < bp->b_dirtyoff)
705 		) {
706 			if (bwrite(bp) == EINTR) {
707 				error = EINTR;
708 				break;
709 			}
710 			goto again;
711 		}
712 
713 		error = uiomove(bp->b_data + boff, bytes, uio);
714 
715 		/*
716 		 * Since this block is being modified, it must be written
717 		 * again and not just committed.  Since write clustering does
718 		 * not work for the stage 1 data write, only the stage 2
719 		 * commit rpc, we have to clear B_CLUSTEROK as well.
720 		 */
721 		bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
722 
723 		if (error) {
724 			brelse(bp);
725 			break;
726 		}
727 
728 		/*
729 		 * Only update dirtyoff/dirtyend if not a degenerate
730 		 * condition.
731 		 *
732 		 * The underlying VM pages have been marked valid by
733 		 * virtue of acquiring the bp.  Because the entire buffer
734 		 * is marked dirty we do not have to worry about cleaning
735 		 * out the related dirty bits (and wouldn't really know
736 		 * how to deal with byte ranges anyway)
737 		 */
738 		if (bytes) {
739 			if (bp->b_dirtyend > 0) {
740 				bp->b_dirtyoff = imin(boff, bp->b_dirtyoff);
741 				bp->b_dirtyend = imax(boff + bytes,
742 						      bp->b_dirtyend);
743 			} else {
744 				bp->b_dirtyoff = boff;
745 				bp->b_dirtyend = boff + bytes;
746 			}
747 		}
748 
749 		/*
750 		 * If the lease is non-cachable or IO_SYNC do bwrite().
751 		 *
752 		 * IO_INVAL appears to be unused.  The idea appears to be
753 		 * to turn off caching in this case.  Very odd.  XXX
754 		 *
755 		 * If nfs_async is set bawrite() will use an unstable write
756 		 * (build dirty bufs on the server), so we might as well
757 		 * push it out with bawrite().  If nfs_async is not set we
758 		 * use bdwrite() to cache dirty bufs on the client.
759 		 */
760 		if (ioflag & IO_SYNC) {
761 			if (ioflag & IO_INVAL)
762 				bp->b_flags |= B_NOCACHE;
763 			error = bwrite(bp);
764 			if (error)
765 				break;
766 		} else if (boff + bytes == biosize && nfs_async) {
767 			bawrite(bp);
768 		} else {
769 			bdwrite(bp);
770 		}
771 	} while (uio->uio_resid > 0 && bytes > 0);
772 
773 	if (haverslock)
774 		nfs_rsunlock(np);
775 
776 	return (error);
777 }
778 
779 /*
780  * Get an nfs cache block.
781  *
782  * Allocate a new one if the block isn't currently in the cache
783  * and return the block marked busy. If the calling process is
784  * interrupted by a signal for an interruptible mount point, return
785  * NULL.
786  *
787  * The caller must carefully deal with the possible B_INVAL state of
788  * the buffer.  nfs_startio() clears B_INVAL (and nfs_asyncio() clears it
789  * indirectly), so synchronous reads can be issued without worrying about
790  * the B_INVAL state.  We have to be a little more careful when dealing
791  * with writes (see comments in nfs_write()) when extending a file past
792  * its EOF.
793  */
794 static struct buf *
795 nfs_getcacheblk(struct vnode *vp, off_t loffset, int size, struct thread *td)
796 {
797 	struct buf *bp;
798 	struct mount *mp;
799 	struct nfsmount *nmp;
800 
801 	mp = vp->v_mount;
802 	nmp = VFSTONFS(mp);
803 
804 	if (nmp->nm_flag & NFSMNT_INT) {
805 		bp = getblk(vp, loffset, size, GETBLK_PCATCH, 0);
806 		while (bp == NULL) {
807 			if (nfs_sigintr(nmp, NULL, td))
808 				return (NULL);
809 			bp = getblk(vp, loffset, size, 0, 2 * hz);
810 		}
811 	} else {
812 		bp = getblk(vp, loffset, size, 0, 0);
813 	}
814 
815 	/*
816 	 * bio2, the 'device' layer.  Since BIOs use 64 bit byte offsets
817 	 * now, no translation is necessary.
818 	 */
819 	bp->b_bio2.bio_offset = loffset;
820 	return (bp);
821 }
822 
823 /*
824  * Flush and invalidate all dirty buffers. If another process is already
825  * doing the flush, just wait for completion.
826  */
827 int
828 nfs_vinvalbuf(struct vnode *vp, int flags, int intrflg)
829 {
830 	struct nfsnode *np = VTONFS(vp);
831 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
832 	int error = 0, slpflag, slptimeo;
833 	thread_t td = curthread;
834 
835 	if (vp->v_flag & VRECLAIMED)
836 		return (0);
837 
838 	if ((nmp->nm_flag & NFSMNT_INT) == 0)
839 		intrflg = 0;
840 	if (intrflg) {
841 		slpflag = PCATCH;
842 		slptimeo = 2 * hz;
843 	} else {
844 		slpflag = 0;
845 		slptimeo = 0;
846 	}
847 	/*
848 	 * First wait for any other process doing a flush to complete.
849 	 */
850 	while (np->n_flag & NFLUSHINPROG) {
851 		np->n_flag |= NFLUSHWANT;
852 		error = tsleep((caddr_t)&np->n_flag, 0, "nfsvinval", slptimeo);
853 		if (error && intrflg && nfs_sigintr(nmp, NULL, td))
854 			return (EINTR);
855 	}
856 
857 	/*
858 	 * Now, flush as required.
859 	 */
860 	np->n_flag |= NFLUSHINPROG;
861 	error = vinvalbuf(vp, flags, slpflag, 0);
862 	while (error) {
863 		if (intrflg && nfs_sigintr(nmp, NULL, td)) {
864 			np->n_flag &= ~NFLUSHINPROG;
865 			if (np->n_flag & NFLUSHWANT) {
866 				np->n_flag &= ~NFLUSHWANT;
867 				wakeup((caddr_t)&np->n_flag);
868 			}
869 			return (EINTR);
870 		}
871 		error = vinvalbuf(vp, flags, 0, slptimeo);
872 	}
873 	np->n_flag &= ~(NLMODIFIED | NFLUSHINPROG);
874 	if (np->n_flag & NFLUSHWANT) {
875 		np->n_flag &= ~NFLUSHWANT;
876 		wakeup((caddr_t)&np->n_flag);
877 	}
878 	return (0);
879 }
880 
881 /*
882  * Return true (non-zero) if the txthread and rxthread are operational
883  * and we do not already have too many not-yet-started BIO's built up.
884  */
885 int
886 nfs_asyncok(struct nfsmount *nmp)
887 {
888 	return (nmp->nm_bioqlen < nfs_maxasyncbio &&
889 		nmp->nm_bioqlen < nmp->nm_maxasync_scaled / NFS_ASYSCALE &&
890 		nmp->nm_rxstate <= NFSSVC_PENDING &&
891 		nmp->nm_txstate <= NFSSVC_PENDING);
892 }
893 
894 /*
895  * The read-ahead code calls this to queue a bio to the txthread.
896  *
897  * We don't touch the bio otherwise... that is, we do not even
898  * construct or send the initial rpc.  The txthread will do it
899  * for us.
900  *
901  * NOTE!  nm_bioqlen is not decremented until the request completes,
902  *	  so it does not reflect the number of bio's on bioq.
903  */
904 void
905 nfs_asyncio(struct vnode *vp, struct bio *bio)
906 {
907 	struct buf *bp = bio->bio_buf;
908 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
909 
910 	KKASSERT(vp->v_tag == VT_NFS);
911 	BUF_KERNPROC(bp);
912 
913 	/*
914 	 * Shortcut swap cache (not done automatically because we are not
915 	 * using bread()).
916 	 */
917 	if (vn_cache_strategy(vp, bio))
918 		return;
919 
920 	bio->bio_driver_info = vp;
921 	crit_enter();
922 	TAILQ_INSERT_TAIL(&nmp->nm_bioq, bio, bio_act);
923 	atomic_add_int(&nmp->nm_bioqlen, 1);
924 	crit_exit();
925 	nfssvc_iod_writer_wakeup(nmp);
926 }
927 
928 /*
929  * nfs_dio()	- Execute a BIO operation synchronously.  The BIO will be
930  *		  completed and its error returned.  The caller is responsible
931  *		  for brelse()ing it.  ONLY USE FOR BIO_SYNC IOs!  Otherwise
932  *		  our error probe will be against an invalid pointer.
933  *
934  * nfs_startio()- Execute a BIO operation assynchronously.
935  *
936  * NOTE: nfs_asyncio() is used to initiate an asynchronous BIO operation,
937  *	 which basically just queues it to the txthread.  nfs_startio()
938  *	 actually initiates the I/O AFTER it has gotten to the txthread.
939  *
940  * NOTE: td might be NULL.
941  *
942  * NOTE: Caller has already busied the I/O.
943  */
944 void
945 nfs_startio(struct vnode *vp, struct bio *bio, struct thread *td)
946 {
947 	struct buf *bp = bio->bio_buf;
948 	struct nfsnode *np;
949 	struct nfsmount *nmp;
950 
951 	KKASSERT(vp->v_tag == VT_NFS);
952 	np = VTONFS(vp);
953 	nmp = VFSTONFS(vp->v_mount);
954 
955 	/*
956 	 * clear B_ERROR and B_INVAL state prior to initiating the I/O.  We
957 	 * do this here so we do not have to do it in all the code that
958 	 * calls us.
959 	 */
960 	bp->b_flags &= ~(B_ERROR | B_INVAL);
961 
962 	KASSERT(bp->b_cmd != BUF_CMD_DONE,
963 		("nfs_doio: bp %p already marked done!", bp));
964 
965 	if (bp->b_cmd == BUF_CMD_READ) {
966 	    switch (vp->v_type) {
967 	    case VREG:
968 		nfsstats.read_bios++;
969 		nfs_readrpc_bio(vp, bio);
970 		break;
971 	    case VLNK:
972 #if 0
973 		bio->bio_offset = 0;
974 		nfsstats.readlink_bios++;
975 		nfs_readlinkrpc_bio(vp, bio);
976 #else
977 		nfs_doio(vp, bio, td);
978 #endif
979 		break;
980 	    case VDIR:
981 		/*
982 		 * NOTE: If nfs_readdirplusrpc_bio() is requested but
983 		 *	 not supported, it will chain to
984 		 *	 nfs_readdirrpc_bio().
985 		 */
986 #if 0
987 		nfsstats.readdir_bios++;
988 		uiop->uio_offset = bio->bio_offset;
989 		if (nmp->nm_flag & NFSMNT_RDIRPLUS)
990 			nfs_readdirplusrpc_bio(vp, bio);
991 		else
992 			nfs_readdirrpc_bio(vp, bio);
993 #else
994 		nfs_doio(vp, bio, td);
995 #endif
996 		break;
997 	    default:
998 		kprintf("nfs_doio:  type %x unexpected\n",vp->v_type);
999 		bp->b_flags |= B_ERROR;
1000 		bp->b_error = EINVAL;
1001 		biodone(bio);
1002 		break;
1003 	    }
1004 	} else {
1005 	    /*
1006 	     * If we only need to commit, try to commit.  If this fails
1007 	     * it will chain through to the write.  Basically all the logic
1008 	     * in nfs_doio() is replicated.
1009 	     */
1010 	    KKASSERT(bp->b_cmd == BUF_CMD_WRITE);
1011 	    if (bp->b_flags & B_NEEDCOMMIT)
1012 		nfs_commitrpc_bio(vp, bio);
1013 	    else
1014 		nfs_writerpc_bio(vp, bio);
1015 	}
1016 }
1017 
1018 int
1019 nfs_doio(struct vnode *vp, struct bio *bio, struct thread *td)
1020 {
1021 	struct buf *bp = bio->bio_buf;
1022 	struct uio *uiop;
1023 	struct nfsnode *np;
1024 	struct nfsmount *nmp;
1025 	int error = 0;
1026 	int iomode, must_commit;
1027 	size_t n;
1028 	struct uio uio;
1029 	struct iovec io;
1030 
1031 #if 0
1032 	/*
1033 	 * Shortcut swap cache (not done automatically because we are not
1034 	 * using bread()).
1035 	 *
1036 	 * XXX The biowait is a hack until we can figure out how to stop a
1037 	 * biodone chain when a middle element is BIO_SYNC.  BIO_SYNC is
1038 	 * set so the bp shouldn't get ripped out from under us.  The only
1039 	 * use-cases are fully synchronous I/O cases.
1040 	 *
1041 	 * XXX This is having problems, give up for now.
1042 	 */
1043 	if (vn_cache_strategy(vp, bio)) {
1044 		kprintf("X");
1045 		error = biowait(&bio->bio_buf->b_bio1, "nfsrsw");
1046 		return (error);
1047 	}
1048 #endif
1049 
1050 	KKASSERT(vp->v_tag == VT_NFS);
1051 	np = VTONFS(vp);
1052 	nmp = VFSTONFS(vp->v_mount);
1053 	uiop = &uio;
1054 	uiop->uio_iov = &io;
1055 	uiop->uio_iovcnt = 1;
1056 	uiop->uio_segflg = UIO_SYSSPACE;
1057 	uiop->uio_td = td;
1058 
1059 	/*
1060 	 * clear B_ERROR and B_INVAL state prior to initiating the I/O.  We
1061 	 * do this here so we do not have to do it in all the code that
1062 	 * calls us.
1063 	 */
1064 	bp->b_flags &= ~(B_ERROR | B_INVAL);
1065 
1066 	KASSERT(bp->b_cmd != BUF_CMD_DONE,
1067 		("nfs_doio: bp %p already marked done!", bp));
1068 
1069 	if (bp->b_cmd == BUF_CMD_READ) {
1070 	    io.iov_len = uiop->uio_resid = (size_t)bp->b_bcount;
1071 	    io.iov_base = bp->b_data;
1072 	    uiop->uio_rw = UIO_READ;
1073 
1074 	    switch (vp->v_type) {
1075 	    case VREG:
1076 		/*
1077 		 * When reading from a regular file zero-fill any residual.
1078 		 * Note that this residual has nothing to do with NFS short
1079 		 * reads, which nfs_readrpc_uio() will handle for us.
1080 		 *
1081 		 * We have to do this because when we are write extending
1082 		 * a file the server may not have the same notion of
1083 		 * filesize as we do.  Our BIOs should already be sized
1084 		 * (b_bcount) to account for the file EOF.
1085 		 */
1086 		nfsstats.read_bios++;
1087 		uiop->uio_offset = bio->bio_offset;
1088 		error = nfs_readrpc_uio(vp, uiop);
1089 		if (error == 0 && uiop->uio_resid) {
1090 			n = (size_t)bp->b_bcount - uiop->uio_resid;
1091 			bzero(bp->b_data + n, bp->b_bcount - n);
1092 			uiop->uio_resid = 0;
1093 		}
1094 		if (td && td->td_proc && (vp->v_flag & VTEXT) &&
1095 		    np->n_mtime != np->n_vattr.va_mtime.tv_sec) {
1096 			uprintf("Process killed due to text file modification\n");
1097 			ksignal(td->td_proc, SIGKILL);
1098 		}
1099 		break;
1100 	    case VLNK:
1101 		uiop->uio_offset = 0;
1102 		nfsstats.readlink_bios++;
1103 		error = nfs_readlinkrpc_uio(vp, uiop);
1104 		break;
1105 	    case VDIR:
1106 		nfsstats.readdir_bios++;
1107 		uiop->uio_offset = bio->bio_offset;
1108 		if (nmp->nm_flag & NFSMNT_RDIRPLUS) {
1109 			error = nfs_readdirplusrpc_uio(vp, uiop);
1110 			if (error == NFSERR_NOTSUPP)
1111 				nmp->nm_flag &= ~NFSMNT_RDIRPLUS;
1112 		}
1113 		if ((nmp->nm_flag & NFSMNT_RDIRPLUS) == 0)
1114 			error = nfs_readdirrpc_uio(vp, uiop);
1115 		/*
1116 		 * end-of-directory sets B_INVAL but does not generate an
1117 		 * error.
1118 		 */
1119 		if (error == 0 && uiop->uio_resid == bp->b_bcount)
1120 			bp->b_flags |= B_INVAL;
1121 		break;
1122 	    default:
1123 		kprintf("nfs_doio:  type %x unexpected\n",vp->v_type);
1124 		break;
1125 	    };
1126 	    if (error) {
1127 		bp->b_flags |= B_ERROR;
1128 		bp->b_error = error;
1129 	    }
1130 	    bp->b_resid = uiop->uio_resid;
1131 	} else {
1132 	    /*
1133 	     * If we only need to commit, try to commit.
1134 	     *
1135 	     * NOTE: The I/O has already been staged for the write and
1136 	     *	     its pages busied, so b_dirtyoff/end is valid.
1137 	     */
1138 	    KKASSERT(bp->b_cmd == BUF_CMD_WRITE);
1139 	    if (bp->b_flags & B_NEEDCOMMIT) {
1140 		    int retv;
1141 		    off_t off;
1142 
1143 		    off = bio->bio_offset + bp->b_dirtyoff;
1144 		    retv = nfs_commitrpc_uio(vp, off,
1145 					     bp->b_dirtyend - bp->b_dirtyoff,
1146 					     td);
1147 		    if (retv == 0) {
1148 			    bp->b_dirtyoff = bp->b_dirtyend = 0;
1149 			    bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1150 			    bp->b_resid = 0;
1151 			    biodone(bio);
1152 			    return(0);
1153 		    }
1154 		    if (retv == NFSERR_STALEWRITEVERF) {
1155 			    nfs_clearcommit(vp->v_mount);
1156 		    }
1157 	    }
1158 
1159 	    /*
1160 	     * Setup for actual write
1161 	     */
1162 	    if (bio->bio_offset + bp->b_dirtyend > np->n_size)
1163 		bp->b_dirtyend = np->n_size - bio->bio_offset;
1164 
1165 	    if (bp->b_dirtyend > bp->b_dirtyoff) {
1166 		io.iov_len = uiop->uio_resid = bp->b_dirtyend
1167 		    - bp->b_dirtyoff;
1168 		uiop->uio_offset = bio->bio_offset + bp->b_dirtyoff;
1169 		io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
1170 		uiop->uio_rw = UIO_WRITE;
1171 		nfsstats.write_bios++;
1172 
1173 		if ((bp->b_flags & (B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == 0)
1174 		    iomode = NFSV3WRITE_UNSTABLE;
1175 		else
1176 		    iomode = NFSV3WRITE_FILESYNC;
1177 
1178 		must_commit = 0;
1179 		error = nfs_writerpc_uio(vp, uiop, &iomode, &must_commit);
1180 
1181 		/*
1182 		 * We no longer try to use kern/vfs_bio's cluster code to
1183 		 * cluster commits, so B_CLUSTEROK is no longer set with
1184 		 * B_NEEDCOMMIT.  The problem is that a vfs_busy_pages()
1185 		 * may have to clear B_NEEDCOMMIT if it finds underlying
1186 		 * pages have been redirtied through a memory mapping
1187 		 * and doing this on a clustered bp will probably cause
1188 		 * a panic, plus the flag in the underlying NFS bufs
1189 		 * making up the cluster bp will not be properly cleared.
1190 		 */
1191 		if (!error && iomode == NFSV3WRITE_UNSTABLE) {
1192 		    bp->b_flags |= B_NEEDCOMMIT;
1193 #if 0
1194 		    /* XXX do not enable commit clustering */
1195 		    if (bp->b_dirtyoff == 0
1196 			&& bp->b_dirtyend == bp->b_bcount)
1197 			bp->b_flags |= B_CLUSTEROK;
1198 #endif
1199 		} else {
1200 		    bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1201 		}
1202 
1203 		/*
1204 		 * For an interrupted write, the buffer is still valid
1205 		 * and the write hasn't been pushed to the server yet,
1206 		 * so we can't set B_ERROR and report the interruption
1207 		 * by setting B_EINTR. For the async case, B_EINTR
1208 		 * is not relevant, so the rpc attempt is essentially
1209 		 * a noop.  For the case of a V3 write rpc not being
1210 		 * committed to stable storage, the block is still
1211 		 * dirty and requires either a commit rpc or another
1212 		 * write rpc with iomode == NFSV3WRITE_FILESYNC before
1213 		 * the block is reused. This is indicated by setting
1214 		 * the B_DELWRI and B_NEEDCOMMIT flags.
1215 		 *
1216 		 * If the buffer is marked B_PAGING, it does not reside on
1217 		 * the vp's paging queues so we cannot call bdirty().  The
1218 		 * bp in this case is not an NFS cache block so we should
1219 		 * be safe. XXX
1220 		 */
1221     		if (error == EINTR
1222 		    || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
1223 			crit_enter();
1224 			bp->b_flags &= ~(B_INVAL|B_NOCACHE);
1225 			if ((bp->b_flags & B_PAGING) == 0)
1226 			    bdirty(bp);
1227 			if (error)
1228 			    bp->b_flags |= B_EINTR;
1229 			crit_exit();
1230 	    	} else {
1231 		    if (error) {
1232 			bp->b_flags |= B_ERROR;
1233 			bp->b_error = np->n_error = error;
1234 			np->n_flag |= NWRITEERR;
1235 		    }
1236 		    bp->b_dirtyoff = bp->b_dirtyend = 0;
1237 		}
1238 		if (must_commit)
1239 		    nfs_clearcommit(vp->v_mount);
1240 		bp->b_resid = uiop->uio_resid;
1241 	    } else {
1242 		bp->b_resid = 0;
1243 	    }
1244 	}
1245 
1246 	/*
1247 	 * I/O was run synchronously, biodone() it and calculate the
1248 	 * error to return.
1249 	 */
1250 	biodone(bio);
1251 	KKASSERT(bp->b_cmd == BUF_CMD_DONE);
1252 	if (bp->b_flags & B_EINTR)
1253 		return (EINTR);
1254 	if (bp->b_flags & B_ERROR)
1255 		return (bp->b_error ? bp->b_error : EIO);
1256 	return (0);
1257 }
1258 
1259 /*
1260  * Handle all truncation, write-extend, and ftruncate()-extend operations
1261  * on the NFS lcient side.
1262  *
1263  * We use the new API in kern/vfs_vm.c to perform these operations in a
1264  * VM-friendly way.  With this API VM pages are properly zerod and pages
1265  * still mapped into the buffer straddling EOF are not invalidated.
1266  */
1267 int
1268 nfs_meta_setsize(struct vnode *vp, struct thread *td, off_t nsize, int trivial)
1269 {
1270 	struct nfsnode *np = VTONFS(vp);
1271 	off_t osize;
1272 	int biosize = vp->v_mount->mnt_stat.f_iosize;
1273 	int error;
1274 
1275 	osize = np->n_size;
1276 	np->n_size = nsize;
1277 
1278 	if (nsize < osize) {
1279 		error = nvtruncbuf(vp, nsize, biosize, -1);
1280 	} else {
1281 		error = nvextendbuf(vp, osize, nsize,
1282 				    biosize, biosize, -1, -1,
1283 				    trivial);
1284 	}
1285 	return(error);
1286 }
1287 
1288 /*
1289  * Synchronous completion for nfs_doio.  Call bpdone() with elseit=FALSE.
1290  * Caller is responsible for brelse()'ing the bp.
1291  */
1292 static void
1293 nfsiodone_sync(struct bio *bio)
1294 {
1295 	bio->bio_flags = 0;
1296 	bpdone(bio->bio_buf, 0);
1297 }
1298 
1299 /*
1300  * nfs read rpc - BIO version
1301  */
1302 void
1303 nfs_readrpc_bio(struct vnode *vp, struct bio *bio)
1304 {
1305 	struct buf *bp = bio->bio_buf;
1306 	u_int32_t *tl;
1307 	struct nfsmount *nmp;
1308 	int error = 0, len, tsiz;
1309 	struct nfsm_info *info;
1310 
1311 	info = kmalloc(sizeof(*info), M_NFSREQ, M_WAITOK);
1312 	info->mrep = NULL;
1313 	info->v3 = NFS_ISV3(vp);
1314 
1315 	nmp = VFSTONFS(vp->v_mount);
1316 	tsiz = bp->b_bcount;
1317 	KKASSERT(tsiz <= nmp->nm_rsize);
1318 	if (bio->bio_offset + tsiz > nmp->nm_maxfilesize) {
1319 		error = EFBIG;
1320 		goto nfsmout;
1321 	}
1322 	nfsstats.rpccnt[NFSPROC_READ]++;
1323 	len = tsiz;
1324 	nfsm_reqhead(info, vp, NFSPROC_READ,
1325 		     NFSX_FH(info->v3) + NFSX_UNSIGNED * 3);
1326 	ERROROUT(nfsm_fhtom(info, vp));
1327 	tl = nfsm_build(info, NFSX_UNSIGNED * 3);
1328 	if (info->v3) {
1329 		txdr_hyper(bio->bio_offset, tl);
1330 		*(tl + 2) = txdr_unsigned(len);
1331 	} else {
1332 		*tl++ = txdr_unsigned(bio->bio_offset);
1333 		*tl++ = txdr_unsigned(len);
1334 		*tl = 0;
1335 	}
1336 	info->bio = bio;
1337 	info->done = nfs_readrpc_bio_done;
1338 	nfsm_request_bio(info, vp, NFSPROC_READ, NULL,
1339 			 nfs_vpcred(vp, ND_READ));
1340 	return;
1341 nfsmout:
1342 	kfree(info, M_NFSREQ);
1343 	bp->b_error = error;
1344 	bp->b_flags |= B_ERROR;
1345 	biodone(bio);
1346 }
1347 
1348 static void
1349 nfs_readrpc_bio_done(nfsm_info_t info)
1350 {
1351 	struct nfsmount *nmp = VFSTONFS(info->vp->v_mount);
1352 	struct bio *bio = info->bio;
1353 	struct buf *bp = bio->bio_buf;
1354 	u_int32_t *tl;
1355 	int attrflag;
1356 	int retlen;
1357 	int eof;
1358 	int error = 0;
1359 
1360 	KKASSERT(info->state == NFSM_STATE_DONE);
1361 
1362 	if (info->v3) {
1363 		ERROROUT(nfsm_postop_attr(info, info->vp, &attrflag,
1364 					 NFS_LATTR_NOSHRINK));
1365 		NULLOUT(tl = nfsm_dissect(info, 2 * NFSX_UNSIGNED));
1366 		eof = fxdr_unsigned(int, *(tl + 1));
1367 	} else {
1368 		ERROROUT(nfsm_loadattr(info, info->vp, NULL));
1369 		eof = 0;
1370 	}
1371 	NEGATIVEOUT(retlen = nfsm_strsiz(info, nmp->nm_rsize));
1372 	ERROROUT(nfsm_mtobio(info, bio, retlen));
1373 	m_freem(info->mrep);
1374 	info->mrep = NULL;
1375 
1376 	/*
1377 	 * No error occured, if retlen is less then bcount and no EOF
1378 	 * and NFSv3 a zero-fill short read occured.
1379 	 *
1380 	 * For NFSv2 a short-read indicates EOF.
1381 	 */
1382 	if (retlen < bp->b_bcount && info->v3 && eof == 0) {
1383 		bzero(bp->b_data + retlen, bp->b_bcount - retlen);
1384 		retlen = bp->b_bcount;
1385 	}
1386 
1387 	/*
1388 	 * If we hit an EOF we still zero-fill, but return the expected
1389 	 * b_resid anyway.  This should normally not occur since async
1390 	 * BIOs are not used for read-before-write case.  Races against
1391 	 * the server can cause it though and we don't want to leave
1392 	 * garbage in the buffer.
1393 	 */
1394 	if (retlen < bp->b_bcount) {
1395 		bzero(bp->b_data + retlen, bp->b_bcount - retlen);
1396 	}
1397 	bp->b_resid = 0;
1398 	/* bp->b_resid = bp->b_bcount - retlen; */
1399 nfsmout:
1400 	kfree(info, M_NFSREQ);
1401 	if (error) {
1402 		bp->b_error = error;
1403 		bp->b_flags |= B_ERROR;
1404 	}
1405 	biodone(bio);
1406 }
1407 
1408 /*
1409  * nfs write call - BIO version
1410  *
1411  * NOTE: Caller has already busied the I/O.
1412  */
1413 void
1414 nfs_writerpc_bio(struct vnode *vp, struct bio *bio)
1415 {
1416 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
1417 	struct nfsnode *np = VTONFS(vp);
1418 	struct buf *bp = bio->bio_buf;
1419 	u_int32_t *tl;
1420 	int len;
1421 	int iomode;
1422 	int error = 0;
1423 	struct nfsm_info *info;
1424 	off_t offset;
1425 
1426 	/*
1427 	 * Setup for actual write.  Just clean up the bio if there
1428 	 * is nothing to do.  b_dirtyoff/end have already been staged
1429 	 * by the bp's pages getting busied.
1430 	 */
1431 	if (bio->bio_offset + bp->b_dirtyend > np->n_size)
1432 		bp->b_dirtyend = np->n_size - bio->bio_offset;
1433 
1434 	if (bp->b_dirtyend <= bp->b_dirtyoff) {
1435 		bp->b_resid = 0;
1436 		biodone(bio);
1437 		return;
1438 	}
1439 	len = bp->b_dirtyend - bp->b_dirtyoff;
1440 	offset = bio->bio_offset + bp->b_dirtyoff;
1441 	if (offset + len > nmp->nm_maxfilesize) {
1442 		bp->b_flags |= B_ERROR;
1443 		bp->b_error = EFBIG;
1444 		biodone(bio);
1445 		return;
1446 	}
1447 	bp->b_resid = len;
1448 	nfsstats.write_bios++;
1449 
1450 	info = kmalloc(sizeof(*info), M_NFSREQ, M_WAITOK);
1451 	info->mrep = NULL;
1452 	info->v3 = NFS_ISV3(vp);
1453 	info->info_writerpc.must_commit = 0;
1454 	if ((bp->b_flags & (B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == 0)
1455 		iomode = NFSV3WRITE_UNSTABLE;
1456 	else
1457 		iomode = NFSV3WRITE_FILESYNC;
1458 
1459 	KKASSERT(len <= nmp->nm_wsize);
1460 
1461 	nfsstats.rpccnt[NFSPROC_WRITE]++;
1462 	nfsm_reqhead(info, vp, NFSPROC_WRITE,
1463 		     NFSX_FH(info->v3) + 5 * NFSX_UNSIGNED + nfsm_rndup(len));
1464 	ERROROUT(nfsm_fhtom(info, vp));
1465 	if (info->v3) {
1466 		tl = nfsm_build(info, 5 * NFSX_UNSIGNED);
1467 		txdr_hyper(offset, tl);
1468 		tl += 2;
1469 		*tl++ = txdr_unsigned(len);
1470 		*tl++ = txdr_unsigned(iomode);
1471 		*tl = txdr_unsigned(len);
1472 	} else {
1473 		u_int32_t x;
1474 
1475 		tl = nfsm_build(info, 4 * NFSX_UNSIGNED);
1476 		/* Set both "begin" and "current" to non-garbage. */
1477 		x = txdr_unsigned((u_int32_t)offset);
1478 		*tl++ = x;	/* "begin offset" */
1479 		*tl++ = x;	/* "current offset" */
1480 		x = txdr_unsigned(len);
1481 		*tl++ = x;	/* total to this offset */
1482 		*tl = x;	/* size of this write */
1483 	}
1484 	ERROROUT(nfsm_biotom(info, bio, bp->b_dirtyoff, len));
1485 	info->bio = bio;
1486 	info->done = nfs_writerpc_bio_done;
1487 	nfsm_request_bio(info, vp, NFSPROC_WRITE, NULL,
1488 			 nfs_vpcred(vp, ND_WRITE));
1489 	return;
1490 nfsmout:
1491 	kfree(info, M_NFSREQ);
1492 	bp->b_error = error;
1493 	bp->b_flags |= B_ERROR;
1494 	biodone(bio);
1495 }
1496 
1497 static void
1498 nfs_writerpc_bio_done(nfsm_info_t info)
1499 {
1500 	struct nfsmount *nmp = VFSTONFS(info->vp->v_mount);
1501 	struct nfsnode *np = VTONFS(info->vp);
1502 	struct bio *bio = info->bio;
1503 	struct buf *bp = bio->bio_buf;
1504 	int wccflag = NFSV3_WCCRATTR;
1505 	int iomode = NFSV3WRITE_FILESYNC;
1506 	int commit;
1507 	int rlen;
1508 	int error;
1509 	int len = bp->b_resid;	/* b_resid was set to shortened length */
1510 	u_int32_t *tl;
1511 
1512 	if (info->v3) {
1513 		/*
1514 		 * The write RPC returns a before and after mtime.  The
1515 		 * nfsm_wcc_data() macro checks the before n_mtime
1516 		 * against the before time and stores the after time
1517 		 * in the nfsnode's cached vattr and n_mtime field.
1518 		 * The NRMODIFIED bit will be set if the before
1519 		 * time did not match the original mtime.
1520 		 */
1521 		wccflag = NFSV3_WCCCHK;
1522 		ERROROUT(nfsm_wcc_data(info, info->vp, &wccflag));
1523 		if (error == 0) {
1524 			NULLOUT(tl = nfsm_dissect(info, 2 * NFSX_UNSIGNED + NFSX_V3WRITEVERF));
1525 			rlen = fxdr_unsigned(int, *tl++);
1526 			if (rlen == 0) {
1527 				error = NFSERR_IO;
1528 				m_freem(info->mrep);
1529 				info->mrep = NULL;
1530 				goto nfsmout;
1531 			} else if (rlen < len) {
1532 #if 0
1533 				/*
1534 				 * XXX what do we do here?
1535 				 */
1536 				backup = len - rlen;
1537 				uiop->uio_iov->iov_base = (char *)uiop->uio_iov->iov_base - backup;
1538 				uiop->uio_iov->iov_len += backup;
1539 				uiop->uio_offset -= backup;
1540 				uiop->uio_resid += backup;
1541 				len = rlen;
1542 #endif
1543 			}
1544 			commit = fxdr_unsigned(int, *tl++);
1545 
1546 			/*
1547 			 * Return the lowest committment level
1548 			 * obtained by any of the RPCs.
1549 			 */
1550 			if (iomode == NFSV3WRITE_FILESYNC)
1551 				iomode = commit;
1552 			else if (iomode == NFSV3WRITE_DATASYNC &&
1553 				commit == NFSV3WRITE_UNSTABLE)
1554 				iomode = commit;
1555 			if ((nmp->nm_state & NFSSTA_HASWRITEVERF) == 0){
1556 			    bcopy(tl, (caddr_t)nmp->nm_verf, NFSX_V3WRITEVERF);
1557 			    nmp->nm_state |= NFSSTA_HASWRITEVERF;
1558 			} else if (bcmp(tl, nmp->nm_verf, NFSX_V3WRITEVERF)) {
1559 			    info->info_writerpc.must_commit = 1;
1560 			    bcopy(tl, (caddr_t)nmp->nm_verf, NFSX_V3WRITEVERF);
1561 			}
1562 		}
1563 	} else {
1564 		ERROROUT(nfsm_loadattr(info, info->vp, NULL));
1565 	}
1566 	m_freem(info->mrep);
1567 	info->mrep = NULL;
1568 	len = 0;
1569 nfsmout:
1570 	if (info->vp->v_mount->mnt_flag & MNT_ASYNC)
1571 		iomode = NFSV3WRITE_FILESYNC;
1572 	bp->b_resid = len;
1573 
1574 	/*
1575 	 * End of RPC.  Now clean up the bp.
1576 	 *
1577 	 * We no longer enable write clustering for commit operations,
1578 	 * See around line 1157 for a more detailed comment.
1579 	 */
1580 	if (!error && iomode == NFSV3WRITE_UNSTABLE) {
1581 		bp->b_flags |= B_NEEDCOMMIT;
1582 #if 0
1583 		/* XXX do not enable commit clustering */
1584 		if (bp->b_dirtyoff == 0 && bp->b_dirtyend == bp->b_bcount)
1585 			bp->b_flags |= B_CLUSTEROK;
1586 #endif
1587 	} else {
1588 		bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1589 	}
1590 
1591 	/*
1592 	 * For an interrupted write, the buffer is still valid
1593 	 * and the write hasn't been pushed to the server yet,
1594 	 * so we can't set B_ERROR and report the interruption
1595 	 * by setting B_EINTR. For the async case, B_EINTR
1596 	 * is not relevant, so the rpc attempt is essentially
1597 	 * a noop.  For the case of a V3 write rpc not being
1598 	 * committed to stable storage, the block is still
1599 	 * dirty and requires either a commit rpc or another
1600 	 * write rpc with iomode == NFSV3WRITE_FILESYNC before
1601 	 * the block is reused. This is indicated by setting
1602 	 * the B_DELWRI and B_NEEDCOMMIT flags.
1603 	 *
1604 	 * If the buffer is marked B_PAGING, it does not reside on
1605 	 * the vp's paging queues so we cannot call bdirty().  The
1606 	 * bp in this case is not an NFS cache block so we should
1607 	 * be safe. XXX
1608 	 */
1609 	if (error == EINTR || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
1610 		crit_enter();
1611 		bp->b_flags &= ~(B_INVAL|B_NOCACHE);
1612 		if ((bp->b_flags & B_PAGING) == 0)
1613 			bdirty(bp);
1614 		if (error)
1615 			bp->b_flags |= B_EINTR;
1616 		crit_exit();
1617 	} else {
1618 		if (error) {
1619 			bp->b_flags |= B_ERROR;
1620 			bp->b_error = np->n_error = error;
1621 			np->n_flag |= NWRITEERR;
1622 		}
1623 		bp->b_dirtyoff = bp->b_dirtyend = 0;
1624 	}
1625 	if (info->info_writerpc.must_commit)
1626 		nfs_clearcommit(info->vp->v_mount);
1627 	kfree(info, M_NFSREQ);
1628 	if (error) {
1629 		bp->b_flags |= B_ERROR;
1630 		bp->b_error = error;
1631 	}
1632 	biodone(bio);
1633 }
1634 
1635 /*
1636  * Nfs Version 3 commit rpc - BIO version
1637  *
1638  * This function issues the commit rpc and will chain to a write
1639  * rpc if necessary.
1640  */
1641 void
1642 nfs_commitrpc_bio(struct vnode *vp, struct bio *bio)
1643 {
1644 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
1645 	struct buf *bp = bio->bio_buf;
1646 	struct nfsm_info *info;
1647 	int error = 0;
1648 	u_int32_t *tl;
1649 
1650 	if ((nmp->nm_state & NFSSTA_HASWRITEVERF) == 0) {
1651 		bp->b_dirtyoff = bp->b_dirtyend = 0;
1652 		bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1653 		bp->b_resid = 0;
1654 		biodone(bio);
1655 		return;
1656 	}
1657 
1658 	info = kmalloc(sizeof(*info), M_NFSREQ, M_WAITOK);
1659 	info->mrep = NULL;
1660 	info->v3 = 1;
1661 
1662 	nfsstats.rpccnt[NFSPROC_COMMIT]++;
1663 	nfsm_reqhead(info, vp, NFSPROC_COMMIT, NFSX_FH(1));
1664 	ERROROUT(nfsm_fhtom(info, vp));
1665 	tl = nfsm_build(info, 3 * NFSX_UNSIGNED);
1666 	txdr_hyper(bio->bio_offset + bp->b_dirtyoff, tl);
1667 	tl += 2;
1668 	*tl = txdr_unsigned(bp->b_dirtyend - bp->b_dirtyoff);
1669 	info->bio = bio;
1670 	info->done = nfs_commitrpc_bio_done;
1671 	nfsm_request_bio(info, vp, NFSPROC_COMMIT, NULL,
1672 			 nfs_vpcred(vp, ND_WRITE));
1673 	return;
1674 nfsmout:
1675 	/*
1676 	 * Chain to write RPC on (early) error
1677 	 */
1678 	kfree(info, M_NFSREQ);
1679 	nfs_writerpc_bio(vp, bio);
1680 }
1681 
1682 static void
1683 nfs_commitrpc_bio_done(nfsm_info_t info)
1684 {
1685 	struct nfsmount *nmp = VFSTONFS(info->vp->v_mount);
1686 	struct bio *bio = info->bio;
1687 	struct buf *bp = bio->bio_buf;
1688 	u_int32_t *tl;
1689 	int wccflag = NFSV3_WCCRATTR;
1690 	int error = 0;
1691 
1692 	ERROROUT(nfsm_wcc_data(info, info->vp, &wccflag));
1693 	if (error == 0) {
1694 		NULLOUT(tl = nfsm_dissect(info, NFSX_V3WRITEVERF));
1695 		if (bcmp(nmp->nm_verf, tl, NFSX_V3WRITEVERF)) {
1696 			bcopy(tl, nmp->nm_verf, NFSX_V3WRITEVERF);
1697 			error = NFSERR_STALEWRITEVERF;
1698 		}
1699 	}
1700 	m_freem(info->mrep);
1701 	info->mrep = NULL;
1702 
1703 	/*
1704 	 * On completion we must chain to a write bio if an
1705 	 * error occurred.
1706 	 */
1707 nfsmout:
1708 	kfree(info, M_NFSREQ);
1709 	if (error == 0) {
1710 		bp->b_dirtyoff = bp->b_dirtyend = 0;
1711 		bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1712 		bp->b_resid = 0;
1713 		biodone(bio);
1714 	} else {
1715 		nfs_writerpc_bio(info->vp, bio);
1716 	}
1717 }
1718 
1719