HAMMER 60I/Many: Mirroring
[dragonfly.git] / sys / vfs / smbfs / smbfs_io.c
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1 /*
2 * Copyright (c) 2000-2001, Boris Popov
3 * All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by Boris Popov.
16 * 4. Neither the name of the author nor the names of any co-contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
32 * $FreeBSD: src/sys/fs/smbfs/smbfs_io.c,v 1.3.2.3 2003/01/17 08:20:26 tjr Exp $
33 * $DragonFly: src/sys/vfs/smbfs/smbfs_io.c,v 1.29 2007/08/28 01:04:33 dillon Exp $
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/resourcevar.h> /* defines plimit structure in proc struct */
39 #include <sys/kernel.h>
40 #include <sys/proc.h>
41 #include <sys/fcntl.h>
42 #include <sys/mount.h>
43 #include <sys/namei.h>
44 #include <sys/vnode.h>
45 #include <sys/dirent.h>
46 #include <sys/signalvar.h>
47 #include <sys/sysctl.h>
49 #include <machine/limits.h>
51 #include <vm/vm.h>
52 #include <vm/vm_page.h>
53 #include <vm/vm_extern.h>
54 #include <vm/vm_object.h>
55 #include <vm/vm_pager.h>
56 #include <vm/vnode_pager.h>
58 #include <sys/ioccom.h>
60 #include <netproto/smb/smb.h>
61 #include <netproto/smb/smb_conn.h>
62 #include <netproto/smb/smb_subr.h>
64 #include "smbfs.h"
65 #include "smbfs_node.h"
66 #include "smbfs_subr.h"
68 #include <sys/buf.h>
70 #include <sys/thread2.h>
72 /*#define SMBFS_RWGENERIC*/
74 extern int smbfs_pbuf_freecnt;
76 static int smbfs_fastlookup = 1;
78 SYSCTL_DECL(_vfs_smbfs);
79 SYSCTL_INT(_vfs_smbfs, OID_AUTO, fastlookup, CTLFLAG_RW, &smbfs_fastlookup, 0, "");
81 static int
82 smbfs_readvdir(struct vnode *vp, struct uio *uio, struct ucred *cred)
84 struct smb_cred scred;
85 struct smbfs_fctx *ctx;
86 struct vnode *newvp;
87 struct smbnode *np = VTOSMB(vp);
88 int error, offset, retval/*, *eofflag = ap->a_eofflag*/;
90 np = VTOSMB(vp);
91 SMBVDEBUG("dirname='%s'\n", np->n_name);
92 smb_makescred(&scred, uio->uio_td, cred);
94 if (uio->uio_resid < 0 || uio->uio_offset < 0 ||
95 uio->uio_offset > INT_MAX)
96 return(EINVAL);
98 error = 0;
99 offset = uio->uio_offset;
101 if (uio->uio_resid > 0 && offset < 1) {
102 if (vop_write_dirent(&error, uio, np->n_ino, DT_DIR, 1, "."))
103 goto done;
104 if (error)
105 goto done;
106 ++offset;
109 if (uio->uio_resid > 0 && offset < 2) {
110 if (vop_write_dirent(&error, uio,
111 np->n_parent ? VTOSMB(np->n_parent)->n_ino : 2,
112 DT_DIR, 2, ".."))
113 goto done;
114 if (error)
115 goto done;
116 ++offset;
119 if (uio->uio_resid == 0)
120 goto done;
122 if (offset != np->n_dirofs || np->n_dirseq == NULL) {
123 SMBVDEBUG("Reopening search %ld:%ld\n", offset, np->n_dirofs);
124 if (np->n_dirseq) {
125 smbfs_findclose(np->n_dirseq, &scred);
126 np->n_dirseq = NULL;
128 np->n_dirofs = 2;
129 error = smbfs_findopen(np, "*", 1,
130 SMB_FA_SYSTEM | SMB_FA_HIDDEN | SMB_FA_DIR,
131 &scred, &ctx);
132 if (error) {
133 SMBVDEBUG("can not open search, error = %d", error);
134 return error;
136 np->n_dirseq = ctx;
137 } else {
138 ctx = np->n_dirseq;
140 while (np->n_dirofs < offset) {
141 error = smbfs_findnext(ctx, offset - np->n_dirofs, &scred);
142 ++np->n_dirofs;
143 if (error) {
144 smbfs_findclose(np->n_dirseq, &scred);
145 np->n_dirseq = NULL;
146 return error == ENOENT ? 0 : error;
149 error = 0;
150 while (uio->uio_resid > 0 && !error) {
152 * Overestimate the size of a record a bit, doesn't really
153 * hurt to be wrong here.
155 error = smbfs_findnext(ctx, uio->uio_resid / _DIRENT_RECLEN(255) + 1, &scred);
156 if (error)
157 break;
158 np->n_dirofs++;
159 ++offset;
161 retval = vop_write_dirent(&error, uio, ctx->f_attr.fa_ino,
162 (ctx->f_attr.fa_attr & SMB_FA_DIR) ? DT_DIR : DT_REG,
163 ctx->f_nmlen, ctx->f_name);
164 if (retval)
165 break;
166 if (smbfs_fastlookup && !error) {
167 error = smbfs_nget(vp->v_mount, vp, ctx->f_name,
168 ctx->f_nmlen, &ctx->f_attr, &newvp);
169 if (!error)
170 vput(newvp);
173 if (error == ENOENT)
174 error = 0;
175 done:
176 uio->uio_offset = offset;
177 return error;
181 smbfs_readvnode(struct vnode *vp, struct uio *uiop, struct ucred *cred)
183 struct thread *td;
184 struct smbmount *smp = VFSTOSMBFS(vp->v_mount);
185 struct smbnode *np = VTOSMB(vp);
186 struct vattr vattr;
187 struct smb_cred scred;
188 int error, lks;
191 * Protect against method which is not supported for now
193 if (uiop->uio_segflg == UIO_NOCOPY)
194 return EOPNOTSUPP;
196 if (vp->v_type != VREG && vp->v_type != VDIR) {
197 SMBFSERR("vn types other than VREG or VDIR are unsupported !\n");
198 return EIO;
200 if (uiop->uio_resid == 0)
201 return 0;
202 if (uiop->uio_offset < 0)
203 return EINVAL;
204 /* if (uiop->uio_offset + uiop->uio_resid > smp->nm_maxfilesize)
205 return EFBIG;*/
206 td = uiop->uio_td;
207 if (vp->v_type == VDIR) {
208 lks = LK_EXCLUSIVE;/*lockstatus(&vp->v_lock, td);*/
209 if (lks == LK_SHARED)
210 vn_lock(vp, LK_UPGRADE | LK_RETRY);
211 error = smbfs_readvdir(vp, uiop, cred);
212 if (lks == LK_SHARED)
213 vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
214 return error;
217 /* biosize = SSTOCN(smp->sm_share)->sc_txmax;*/
218 if (np->n_flag & NMODIFIED) {
219 smbfs_attr_cacheremove(vp);
220 error = VOP_GETATTR(vp, &vattr);
221 if (error)
222 return error;
223 np->n_mtime.tv_sec = vattr.va_mtime.tv_sec;
224 } else {
225 error = VOP_GETATTR(vp, &vattr);
226 if (error)
227 return error;
228 if (np->n_mtime.tv_sec != vattr.va_mtime.tv_sec) {
229 error = smbfs_vinvalbuf(vp, V_SAVE, 1);
230 if (error)
231 return error;
232 np->n_mtime.tv_sec = vattr.va_mtime.tv_sec;
235 smb_makescred(&scred, td, cred);
236 return smb_read(smp->sm_share, np->n_fid, uiop, &scred);
240 smbfs_writevnode(struct vnode *vp, struct uio *uiop,
241 struct ucred *cred, int ioflag)
243 struct thread *td;
244 struct smbmount *smp = VTOSMBFS(vp);
245 struct smbnode *np = VTOSMB(vp);
246 struct smb_cred scred;
247 int error = 0;
249 if (vp->v_type != VREG) {
250 SMBERROR("vn types other than VREG unsupported !\n");
251 return EIO;
253 SMBVDEBUG("ofs=%d,resid=%d\n",(int)uiop->uio_offset, uiop->uio_resid);
254 if (uiop->uio_offset < 0)
255 return EINVAL;
256 /* if (uiop->uio_offset + uiop->uio_resid > smp->nm_maxfilesize)
257 return (EFBIG);*/
258 td = uiop->uio_td;
259 if (ioflag & (IO_APPEND | IO_SYNC)) {
260 if (np->n_flag & NMODIFIED) {
261 smbfs_attr_cacheremove(vp);
262 error = smbfs_vinvalbuf(vp, V_SAVE, 1);
263 if (error)
264 return error;
266 if (ioflag & IO_APPEND) {
267 #if notyet
269 * File size can be changed by another client
271 smbfs_attr_cacheremove(vp);
272 error = VOP_GETATTR(vp, &vattr);
273 if (error) return (error);
274 #endif
275 uiop->uio_offset = np->n_size;
278 if (uiop->uio_resid == 0)
279 return 0;
280 if (td->td_proc &&
281 uiop->uio_offset + uiop->uio_resid >
282 td->td_proc->p_rlimit[RLIMIT_FSIZE].rlim_cur) {
283 lwpsignal(td->td_proc, td->td_lwp, SIGXFSZ);
284 return EFBIG;
286 smb_makescred(&scred, td, cred);
287 error = smb_write(smp->sm_share, np->n_fid, uiop, &scred);
288 SMBVDEBUG("after: ofs=%d,resid=%d\n",(int)uiop->uio_offset, uiop->uio_resid);
289 if (!error) {
290 if (uiop->uio_offset > np->n_size) {
291 np->n_size = uiop->uio_offset;
292 vnode_pager_setsize(vp, np->n_size);
295 return error;
299 * Do an I/O operation to/from a cache block.
302 smbfs_doio(struct vnode *vp, struct bio *bio, struct ucred *cr, struct thread *td)
304 struct buf *bp = bio->bio_buf;
305 struct smbmount *smp = VFSTOSMBFS(vp->v_mount);
306 struct smbnode *np = VTOSMB(vp);
307 struct uio uio, *uiop = &uio;
308 struct iovec io;
309 struct smb_cred scred;
310 int error = 0;
312 uiop->uio_iov = &io;
313 uiop->uio_iovcnt = 1;
314 uiop->uio_segflg = UIO_SYSSPACE;
315 uiop->uio_td = td;
317 smb_makescred(&scred, td, cr);
319 if (bp->b_cmd == BUF_CMD_READ) {
320 io.iov_len = uiop->uio_resid = bp->b_bcount;
321 io.iov_base = bp->b_data;
322 uiop->uio_rw = UIO_READ;
323 switch (vp->v_type) {
324 case VREG:
325 uiop->uio_offset = bio->bio_offset;
326 error = smb_read(smp->sm_share, np->n_fid, uiop, &scred);
327 if (error)
328 break;
329 if (uiop->uio_resid) {
330 int left = uiop->uio_resid;
331 int nread = bp->b_bcount - left;
332 if (left > 0)
333 bzero((char *)bp->b_data + nread, left);
335 break;
336 default:
337 kprintf("smbfs_doio: type %x unexpected\n",vp->v_type);
338 break;
340 if (error) {
341 bp->b_error = error;
342 bp->b_flags |= B_ERROR;
344 } else { /* write */
345 KKASSERT(bp->b_cmd == BUF_CMD_WRITE);
346 if (bio->bio_offset + bp->b_dirtyend > np->n_size)
347 bp->b_dirtyend = np->n_size - bio->bio_offset;
349 if (bp->b_dirtyend > bp->b_dirtyoff) {
350 io.iov_len = uiop->uio_resid = bp->b_dirtyend - bp->b_dirtyoff;
351 uiop->uio_offset = bio->bio_offset + bp->b_dirtyoff;
352 io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
353 uiop->uio_rw = UIO_WRITE;
354 error = smb_write(smp->sm_share, np->n_fid, uiop, &scred);
357 * For an interrupted write, the buffer is still valid
358 * and the write hasn't been pushed to the server yet,
359 * so we can't set BIO_ERROR and report the interruption
360 * by setting B_EINTR. For the B_ASYNC case, B_EINTR
361 * is not relevant, so the rpc attempt is essentially
362 * a noop. For the case of a V3 write rpc not being
363 * committed to stable storage, the block is still
364 * dirty and requires either a commit rpc or another
365 * write rpc with iomode == NFSV3WRITE_FILESYNC before
366 * the block is reused. This is indicated by setting
367 * the B_DELWRI and B_NEEDCOMMIT flags.
369 if (error == EINTR
370 || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
372 crit_enter();
373 bp->b_flags &= ~(B_INVAL|B_NOCACHE);
374 if ((bp->b_flags & B_ASYNC) == 0)
375 bp->b_flags |= B_EINTR;
376 if ((bp->b_flags & B_PAGING) == 0)
377 bdirty(bp);
378 if ((bp->b_flags & B_ASYNC) == 0)
379 bp->b_flags |= B_EINTR;
380 crit_exit();
381 } else {
382 if (error) {
383 bp->b_flags |= B_ERROR;
384 bp->b_error = error;
386 bp->b_dirtyoff = bp->b_dirtyend = 0;
388 } else {
389 bp->b_resid = 0;
390 biodone(bio);
391 return 0;
394 bp->b_resid = uiop->uio_resid;
395 biodone(bio);
396 return error;
400 * Vnode op for VM getpages.
401 * Wish wish .... get rid from multiple IO routines
403 * smbfs_getpages(struct vnode *a_vp, vm_page_t *a_m, int a_count,
404 * int a_reqpage, vm_ooffset_t a_offset)
407 smbfs_getpages(struct vop_getpages_args *ap)
409 #ifdef SMBFS_RWGENERIC
410 return vop_stdgetpages(ap);
411 #else
412 int i, error, nextoff, size, toff, npages, count;
413 int doclose;
414 struct uio uio;
415 struct iovec iov;
416 vm_offset_t kva;
417 struct buf *bp;
418 struct vnode *vp;
419 struct thread *td = curthread; /* XXX */
420 struct ucred *cred;
421 struct smbmount *smp;
422 struct smbnode *np;
423 struct smb_cred scred;
424 vm_page_t *pages;
426 KKASSERT(td->td_proc);
428 vp = ap->a_vp;
429 cred = td->td_proc->p_ucred;
430 np = VTOSMB(vp);
431 smp = VFSTOSMBFS(vp->v_mount);
432 pages = ap->a_m;
433 count = ap->a_count;
435 if (vp->v_object == NULL) {
436 kprintf("smbfs_getpages: called with non-merged cache vnode??\n");
437 return VM_PAGER_ERROR;
439 smb_makescred(&scred, td, cred);
441 bp = getpbuf(&smbfs_pbuf_freecnt);
442 npages = btoc(count);
443 kva = (vm_offset_t) bp->b_data;
444 pmap_qenter(kva, pages, npages);
446 iov.iov_base = (caddr_t) kva;
447 iov.iov_len = count;
448 uio.uio_iov = &iov;
449 uio.uio_iovcnt = 1;
450 uio.uio_offset = IDX_TO_OFF(pages[0]->pindex);
451 uio.uio_resid = count;
452 uio.uio_segflg = UIO_SYSSPACE;
453 uio.uio_rw = UIO_READ;
454 uio.uio_td = td;
457 * This is kinda nasty. Since smbfs is physically closing the
458 * fid on close(), we have to reopen it if necessary. There are
459 * other races here too, such as if another process opens the same
460 * file while we are blocked in read. XXX
462 error = 0;
463 doclose = 0;
464 if (np->n_opencount == 0) {
465 error = smbfs_smb_open(np, SMB_AM_OPENREAD, &scred);
466 if (error == 0)
467 doclose = 1;
469 if (error == 0)
470 error = smb_read(smp->sm_share, np->n_fid, &uio, &scred);
471 if (doclose)
472 smbfs_smb_close(smp->sm_share, np->n_fid, NULL, &scred);
473 pmap_qremove(kva, npages);
475 relpbuf(bp, &smbfs_pbuf_freecnt);
477 if (error && (uio.uio_resid == count)) {
478 kprintf("smbfs_getpages: error %d\n",error);
479 for (i = 0; i < npages; i++) {
480 if (ap->a_reqpage != i)
481 vnode_pager_freepage(pages[i]);
483 return VM_PAGER_ERROR;
486 size = count - uio.uio_resid;
488 for (i = 0, toff = 0; i < npages; i++, toff = nextoff) {
489 vm_page_t m;
490 nextoff = toff + PAGE_SIZE;
491 m = pages[i];
493 m->flags &= ~PG_ZERO;
495 if (nextoff <= size) {
496 m->valid = VM_PAGE_BITS_ALL;
497 m->dirty = 0;
498 } else {
499 int nvalid = ((size + DEV_BSIZE - 1) - toff) & ~(DEV_BSIZE - 1);
500 vm_page_set_validclean(m, 0, nvalid);
503 if (i != ap->a_reqpage) {
505 * Whether or not to leave the page activated is up in
506 * the air, but we should put the page on a page queue
507 * somewhere (it already is in the object). Result:
508 * It appears that emperical results show that
509 * deactivating pages is best.
513 * Just in case someone was asking for this page we
514 * now tell them that it is ok to use.
516 if (!error) {
517 if (m->flags & PG_WANTED)
518 vm_page_activate(m);
519 else
520 vm_page_deactivate(m);
521 vm_page_wakeup(m);
522 } else {
523 vnode_pager_freepage(m);
527 return 0;
528 #endif /* SMBFS_RWGENERIC */
532 * Vnode op for VM putpages.
533 * possible bug: all IO done in sync mode
534 * Note that vop_close always invalidate pages before close, so it's
535 * not necessary to open vnode.
537 * smbfs_putpages(struct vnode *a_vp, vm_page_t *a_m, int a_count, int a_sync,
538 * int *a_rtvals, vm_ooffset_t a_offset)
541 smbfs_putpages(struct vop_putpages_args *ap)
543 int error;
544 struct vnode *vp = ap->a_vp;
545 struct thread *td = curthread; /* XXX */
546 struct ucred *cred;
548 #ifdef SMBFS_RWGENERIC
549 KKASSERT(td->td_proc);
550 cred = td->td_proc->p_ucred;
551 VOP_OPEN(vp, FWRITE, cred, NULL);
552 error = vop_stdputpages(ap);
553 VOP_CLOSE(vp, FWRITE, cred);
554 return error;
555 #else
556 struct uio uio;
557 struct iovec iov;
558 vm_offset_t kva;
559 struct buf *bp;
560 int i, npages, count;
561 int doclose;
562 int *rtvals;
563 struct smbmount *smp;
564 struct smbnode *np;
565 struct smb_cred scred;
566 vm_page_t *pages;
568 KKASSERT(td->td_proc);
569 cred = td->td_proc->p_ucred;
570 /* VOP_OPEN(vp, FWRITE, cred, NULL);*/
571 np = VTOSMB(vp);
572 smp = VFSTOSMBFS(vp->v_mount);
573 pages = ap->a_m;
574 count = ap->a_count;
575 rtvals = ap->a_rtvals;
576 npages = btoc(count);
578 for (i = 0; i < npages; i++) {
579 rtvals[i] = VM_PAGER_AGAIN;
582 bp = getpbuf(&smbfs_pbuf_freecnt);
583 kva = (vm_offset_t) bp->b_data;
584 pmap_qenter(kva, pages, npages);
586 iov.iov_base = (caddr_t) kva;
587 iov.iov_len = count;
588 uio.uio_iov = &iov;
589 uio.uio_iovcnt = 1;
590 uio.uio_offset = IDX_TO_OFF(pages[0]->pindex);
591 uio.uio_resid = count;
592 uio.uio_segflg = UIO_SYSSPACE;
593 uio.uio_rw = UIO_WRITE;
594 uio.uio_td = td;
595 SMBVDEBUG("ofs=%d,resid=%d\n",(int)uio.uio_offset, uio.uio_resid);
597 smb_makescred(&scred, td, cred);
600 * This is kinda nasty. Since smbfs is physically closing the
601 * fid on close(), we have to reopen it if necessary. There are
602 * other races here too, such as if another process opens the same
603 * file while we are blocked in read, or the file is open read-only
604 * XXX
606 error = 0;
607 doclose = 0;
608 if (np->n_opencount == 0) {
609 error = smbfs_smb_open(np, SMB_AM_OPENRW, &scred);
610 if (error == 0)
611 doclose = 1;
613 if (error == 0)
614 error = smb_write(smp->sm_share, np->n_fid, &uio, &scred);
615 if (doclose)
616 smbfs_smb_close(smp->sm_share, np->n_fid, NULL, &scred);
617 /* VOP_CLOSE(vp, FWRITE, cred);*/
618 SMBVDEBUG("paged write done: %d\n", error);
620 pmap_qremove(kva, npages);
621 relpbuf(bp, &smbfs_pbuf_freecnt);
623 if (!error) {
624 int nwritten = round_page(count - uio.uio_resid) / PAGE_SIZE;
625 for (i = 0; i < nwritten; i++) {
626 rtvals[i] = VM_PAGER_OK;
627 pages[i]->dirty = 0;
630 return rtvals[0];
631 #endif /* SMBFS_RWGENERIC */
635 * Flush and invalidate all dirty buffers. If another process is already
636 * doing the flush, just wait for completion.
639 smbfs_vinvalbuf(struct vnode *vp, int flags, int intrflg)
641 struct smbnode *np = VTOSMB(vp);
642 int error = 0, slpflag, slptimeo;
644 if (vp->v_flag & VRECLAIMED)
645 return 0;
646 if (intrflg) {
647 slpflag = PCATCH;
648 slptimeo = 2 * hz;
649 } else {
650 slpflag = 0;
651 slptimeo = 0;
653 while (np->n_flag & NFLUSHINPROG) {
654 np->n_flag |= NFLUSHWANT;
655 error = tsleep((caddr_t)&np->n_flag, 0, "smfsvinv", slptimeo);
656 error = smb_proc_intr(curthread);
657 if (error == EINTR && intrflg)
658 return EINTR;
660 np->n_flag |= NFLUSHINPROG;
661 error = vinvalbuf(vp, flags, slpflag, 0);
662 while (error) {
663 if (intrflg && (error == ERESTART || error == EINTR)) {
664 np->n_flag &= ~NFLUSHINPROG;
665 if (np->n_flag & NFLUSHWANT) {
666 np->n_flag &= ~NFLUSHWANT;
667 wakeup((caddr_t)&np->n_flag);
669 return EINTR;
671 error = vinvalbuf(vp, flags, slpflag, 0);
673 np->n_flag &= ~(NMODIFIED | NFLUSHINPROG);
674 if (np->n_flag & NFLUSHWANT) {
675 np->n_flag &= ~NFLUSHWANT;
676 wakeup((caddr_t)&np->n_flag);
678 return (error);