xref: /dragonfly/sys/kern/vfs_vnops.c (revision fe76c4fb)
1 /*
2  * Copyright (c) 1982, 1986, 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)vfs_vnops.c	8.2 (Berkeley) 1/21/94
39  * $FreeBSD: src/sys/kern/vfs_vnops.c,v 1.87.2.13 2002/12/29 18:19:53 dillon Exp $
40  * $DragonFly: src/sys/kern/vfs_vnops.c,v 1.41 2006/06/13 08:12:03 dillon Exp $
41  */
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/fcntl.h>
46 #include <sys/file.h>
47 #include <sys/stat.h>
48 #include <sys/proc.h>
49 #include <sys/mount.h>
50 #include <sys/nlookup.h>
51 #include <sys/vnode.h>
52 #include <sys/buf.h>
53 #include <sys/filio.h>
54 #include <sys/ttycom.h>
55 #include <sys/conf.h>
56 #include <sys/syslog.h>
57 
58 static int vn_closefile (struct file *fp);
59 static int vn_ioctl (struct file *fp, u_long com, caddr_t data,
60 		struct ucred *cred);
61 static int vn_read (struct file *fp, struct uio *uio,
62 		struct ucred *cred, int flags);
63 static int svn_read (struct file *fp, struct uio *uio,
64 		struct ucred *cred, int flags);
65 static int vn_poll (struct file *fp, int events, struct ucred *cred);
66 static int vn_kqfilter (struct file *fp, struct knote *kn);
67 static int vn_statfile (struct file *fp, struct stat *sb, struct ucred *cred);
68 static int vn_write (struct file *fp, struct uio *uio,
69 		struct ucred *cred, int flags);
70 static int svn_write (struct file *fp, struct uio *uio,
71 		struct ucred *cred, int flags);
72 
73 struct fileops vnode_fileops = {
74 	NULL,	/* port */
75 	NULL,	/* clone */
76 	vn_read, vn_write, vn_ioctl, vn_poll, vn_kqfilter,
77 	vn_statfile, vn_closefile, nofo_shutdown
78 };
79 
80 struct fileops specvnode_fileops = {
81 	NULL,	/* port */
82 	NULL,	/* clone */
83 	svn_read, svn_write, vn_ioctl, vn_poll, vn_kqfilter,
84 	vn_statfile, vn_closefile, nofo_shutdown
85 };
86 
87 /*
88  * Shortcut the device read/write.  This avoids a lot of vnode junk.
89  * Basically the specfs vnops for read and write take the locked vnode,
90  * unlock it (because we can't hold the vnode locked while reading or writing
91  * a device which may block indefinitely), issues the device operation, then
92  * relock the vnode before returning, plus other junk.  This bypasses all
93  * of that and just does the device operation.
94  */
95 void
96 vn_setspecops(struct file *fp)
97 {
98 	if (vfs_fastdev && fp->f_ops == &vnode_fileops) {
99 		fp->f_ops = &specvnode_fileops;
100 	}
101 }
102 
103 /*
104  * Common code for vnode open operations.  Check permissions, and call
105  * the VOP_NOPEN or VOP_NCREATE routine.
106  *
107  * The caller is responsible for setting up nd with nlookup_init() and
108  * for cleaning it up with nlookup_done(), whether we return an error
109  * or not.
110  *
111  * On success nd->nl_open_vp will hold a referenced and, if requested,
112  * locked vnode.  A locked vnode is requested via NLC_LOCKVP.  If fp
113  * is non-NULL the vnode will be installed in the file pointer.
114  *
115  * NOTE: The vnode is referenced just once on return whether or not it
116  * is also installed in the file pointer.
117  */
118 int
119 vn_open(struct nlookupdata *nd, struct file *fp, int fmode, int cmode)
120 {
121 	struct vnode *vp;
122 	struct ucred *cred = nd->nl_cred;
123 	struct vattr vat;
124 	struct vattr *vap = &vat;
125 	struct namecache *ncp;
126 	int mode, error;
127 
128 	/*
129 	 * Lookup the path and create or obtain the vnode.  After a
130 	 * successful lookup a locked nd->nl_ncp will be returned.
131 	 *
132 	 * The result of this section should be a locked vnode.
133 	 *
134 	 * XXX with only a little work we should be able to avoid locking
135 	 * the vnode if FWRITE, O_CREAT, and O_TRUNC are *not* set.
136 	 */
137 	if (fmode & O_CREAT) {
138 		/*
139 		 * CONDITIONAL CREATE FILE CASE
140 		 *
141 		 * Setting NLC_CREATE causes a negative hit to store
142 		 * the negative hit ncp and not return an error.  Then
143 		 * nc_error or nc_vp may be checked to see if the ncp
144 		 * represents a negative hit.  NLC_CREATE also requires
145 		 * write permission on the governing directory or EPERM
146 		 * is returned.
147 		 */
148 		if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0)
149 			nd->nl_flags |= NLC_FOLLOW;
150 		nd->nl_flags |= NLC_CREATE;
151 		bwillwrite();
152 		error = nlookup(nd);
153 	} else {
154 		/*
155 		 * NORMAL OPEN FILE CASE
156 		 */
157 		error = nlookup(nd);
158 	}
159 
160 	if (error)
161 		return (error);
162 	ncp = nd->nl_ncp;
163 
164 	/*
165 	 * split case to allow us to re-resolve and retry the ncp in case
166 	 * we get ESTALE.
167 	 */
168 again:
169 	if (fmode & O_CREAT) {
170 		if (ncp->nc_vp == NULL) {
171 			VATTR_NULL(vap);
172 			vap->va_type = VREG;
173 			vap->va_mode = cmode;
174 			if (fmode & O_EXCL)
175 				vap->va_vaflags |= VA_EXCLUSIVE;
176 			error = VOP_NCREATE(ncp, &vp, nd->nl_cred, vap);
177 			if (error)
178 				return (error);
179 			fmode &= ~O_TRUNC;
180 			ASSERT_VOP_LOCKED(vp, "create");
181 			/* locked vnode is returned */
182 		} else {
183 			if (fmode & O_EXCL) {
184 				error = EEXIST;
185 			} else {
186 				error = cache_vget(ncp, cred,
187 						    LK_EXCLUSIVE, &vp);
188 			}
189 			if (error)
190 				return (error);
191 			fmode &= ~O_CREAT;
192 		}
193 	} else {
194 		error = cache_vget(ncp, cred, LK_EXCLUSIVE, &vp);
195 		if (error)
196 			return (error);
197 	}
198 
199 	/*
200 	 * We have a locked vnode and ncp now.  Note that the ncp will
201 	 * be cleaned up by the caller if nd->nl_ncp is left intact.
202 	 */
203 	if (vp->v_type == VLNK) {
204 		error = EMLINK;
205 		goto bad;
206 	}
207 	if (vp->v_type == VSOCK) {
208 		error = EOPNOTSUPP;
209 		goto bad;
210 	}
211 	if ((fmode & O_CREAT) == 0) {
212 		mode = 0;
213 		if (fmode & (FWRITE | O_TRUNC)) {
214 			if (vp->v_type == VDIR) {
215 				error = EISDIR;
216 				goto bad;
217 			}
218 			error = vn_writechk(vp);
219 			if (error) {
220 				/*
221 				 * Special stale handling, re-resolve the
222 				 * vnode.
223 				 */
224 				if (error == ESTALE) {
225 					vput(vp);
226 					vp = NULL;
227 					cache_setunresolved(ncp);
228 					error = cache_resolve(ncp, cred);
229 					if (error == 0)
230 						goto again;
231 				}
232 				goto bad;
233 			}
234 			mode |= VWRITE;
235 		}
236 		if (fmode & FREAD)
237 			mode |= VREAD;
238 		if (mode) {
239 		        error = VOP_ACCESS(vp, mode, cred);
240 			if (error) {
241 				/*
242 				 * Special stale handling, re-resolve the
243 				 * vnode.
244 				 */
245 				if (error == ESTALE) {
246 					vput(vp);
247 					vp = NULL;
248 					cache_setunresolved(ncp);
249 					error = cache_resolve(ncp, cred);
250 					if (error == 0)
251 						goto again;
252 				}
253 				goto bad;
254 			}
255 		}
256 	}
257 	if (fmode & O_TRUNC) {
258 		VOP_UNLOCK(vp, 0);			/* XXX */
259 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);	/* XXX */
260 		VATTR_NULL(vap);
261 		vap->va_size = 0;
262 		error = VOP_SETATTR(vp, vap, cred);
263 		if (error)
264 			goto bad;
265 	}
266 
267 	/*
268 	 * Setup the fp so VOP_OPEN can override it.  No descriptor has been
269 	 * associated with the fp yet so we own it clean.  f_ncp inherits
270 	 * nl_ncp .
271 	 */
272 	if (fp) {
273 		if (vp->v_type == VDIR) {
274 			fp->f_ncp = nd->nl_ncp;
275 			nd->nl_ncp = NULL;
276 			cache_unlock(fp->f_ncp);
277 		}
278 	}
279 
280 	/*
281 	 * Get rid of nl_ncp.  vn_open does not return it (it returns the
282 	 * vnode or the file pointer).  Note: we can't leave nl_ncp locked
283 	 * through the VOP_OPEN anyway since the VOP_OPEN may block, e.g.
284 	 * on /dev/ttyd0
285 	 */
286 	if (nd->nl_ncp) {
287 		cache_put(nd->nl_ncp);
288 		nd->nl_ncp = NULL;
289 	}
290 
291 	error = VOP_OPEN(vp, fmode, cred, fp);
292 	if (error) {
293 		/*
294 		 * setting f_ops to &badfileops will prevent the descriptor
295 		 * code from trying to close and release the vnode, since
296 		 * the open failed we do not want to call close.
297 		 */
298 		if (fp) {
299 			fp->f_data = NULL;
300 			fp->f_ops = &badfileops;
301 		}
302 		goto bad;
303 	}
304 
305 #if 0
306 	/*
307 	 * Assert that VREG files have been setup for vmio.
308 	 */
309 	KASSERT(vp->v_type != VREG || vp->v_object != NULL,
310 		("vn_open: regular file was not VMIO enabled!"));
311 #endif
312 
313 	/*
314 	 * Return the vnode.  XXX needs some cleaning up.  The vnode is
315 	 * only returned in the fp == NULL case.
316 	 */
317 	if (fp == NULL) {
318 		nd->nl_open_vp = vp;
319 		nd->nl_vp_fmode = fmode;
320 		if ((nd->nl_flags & NLC_LOCKVP) == 0)
321 			VOP_UNLOCK(vp, 0);
322 	} else {
323 		vput(vp);
324 	}
325 	return (0);
326 bad:
327 	if (vp)
328 		vput(vp);
329 	return (error);
330 }
331 
332 /*
333  * Check for write permissions on the specified vnode.
334  * Prototype text segments cannot be written.
335  */
336 int
337 vn_writechk(vp)
338 	struct vnode *vp;
339 {
340 
341 	/*
342 	 * If there's shared text associated with
343 	 * the vnode, try to free it up once.  If
344 	 * we fail, we can't allow writing.
345 	 */
346 	if (vp->v_flag & VTEXT)
347 		return (ETXTBSY);
348 	return (0);
349 }
350 
351 /*
352  * Vnode close call
353  */
354 int
355 vn_close(struct vnode *vp, int flags)
356 {
357 	int error;
358 
359 	if ((error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY)) == 0) {
360 		error = VOP_CLOSE(vp, flags);
361 		VOP_UNLOCK(vp, 0);
362 	}
363 	vrele(vp);
364 	return (error);
365 }
366 
367 static __inline
368 int
369 sequential_heuristic(struct uio *uio, struct file *fp)
370 {
371 	/*
372 	 * Sequential heuristic - detect sequential operation
373 	 */
374 	if ((uio->uio_offset == 0 && fp->f_seqcount > 0) ||
375 	    uio->uio_offset == fp->f_nextoff) {
376 		int tmpseq = fp->f_seqcount;
377 		/*
378 		 * XXX we assume that the filesystem block size is
379 		 * the default.  Not true, but still gives us a pretty
380 		 * good indicator of how sequential the read operations
381 		 * are.
382 		 */
383 		tmpseq += (uio->uio_resid + BKVASIZE - 1) / BKVASIZE;
384 		if (tmpseq > IO_SEQMAX)
385 			tmpseq = IO_SEQMAX;
386 		fp->f_seqcount = tmpseq;
387 		return(fp->f_seqcount << IO_SEQSHIFT);
388 	}
389 
390 	/*
391 	 * Not sequential, quick draw-down of seqcount
392 	 */
393 	if (fp->f_seqcount > 1)
394 		fp->f_seqcount = 1;
395 	else
396 		fp->f_seqcount = 0;
397 	return(0);
398 }
399 
400 /*
401  * Package up an I/O request on a vnode into a uio and do it.
402  */
403 int
404 vn_rdwr(enum uio_rw rw, struct vnode *vp, caddr_t base, int len,
405 	off_t offset, enum uio_seg segflg, int ioflg,
406 	struct ucred *cred, int *aresid)
407 {
408 	struct uio auio;
409 	struct iovec aiov;
410 	int error;
411 
412 	if ((ioflg & IO_NODELOCKED) == 0)
413 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
414 	auio.uio_iov = &aiov;
415 	auio.uio_iovcnt = 1;
416 	aiov.iov_base = base;
417 	aiov.iov_len = len;
418 	auio.uio_resid = len;
419 	auio.uio_offset = offset;
420 	auio.uio_segflg = segflg;
421 	auio.uio_rw = rw;
422 	auio.uio_td = curthread;
423 	if (rw == UIO_READ) {
424 		error = VOP_READ(vp, &auio, ioflg, cred);
425 	} else {
426 		error = VOP_WRITE(vp, &auio, ioflg, cred);
427 	}
428 	if (aresid)
429 		*aresid = auio.uio_resid;
430 	else
431 		if (auio.uio_resid && error == 0)
432 			error = EIO;
433 	if ((ioflg & IO_NODELOCKED) == 0)
434 		VOP_UNLOCK(vp, 0);
435 	return (error);
436 }
437 
438 /*
439  * Package up an I/O request on a vnode into a uio and do it.  The I/O
440  * request is split up into smaller chunks and we try to avoid saturating
441  * the buffer cache while potentially holding a vnode locked, so we
442  * check bwillwrite() before calling vn_rdwr().  We also call uio_yield()
443  * to give other processes a chance to lock the vnode (either other processes
444  * core'ing the same binary, or unrelated processes scanning the directory).
445  */
446 int
447 vn_rdwr_inchunks(enum uio_rw rw, struct vnode *vp, caddr_t base, int len,
448 		 off_t offset, enum uio_seg segflg, int ioflg,
449 		 struct ucred *cred, int *aresid)
450 {
451 	int error = 0;
452 
453 	do {
454 		int chunk;
455 
456 		/*
457 		 * Force `offset' to a multiple of MAXBSIZE except possibly
458 		 * for the first chunk, so that filesystems only need to
459 		 * write full blocks except possibly for the first and last
460 		 * chunks.
461 		 */
462 		chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE;
463 
464 		if (chunk > len)
465 			chunk = len;
466 		if (rw != UIO_READ && vp->v_type == VREG)
467 			bwillwrite();
468 		error = vn_rdwr(rw, vp, base, chunk, offset, segflg,
469 			    ioflg, cred, aresid);
470 		len -= chunk;	/* aresid calc already includes length */
471 		if (error)
472 			break;
473 		offset += chunk;
474 		base += chunk;
475 		uio_yield();
476 	} while (len);
477 	if (aresid)
478 		*aresid += len;
479 	return (error);
480 }
481 
482 /*
483  * MPALMOSTSAFE - acquires mplock
484  */
485 static int
486 vn_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
487 {
488 	struct vnode *vp;
489 	int error, ioflag;
490 
491 	get_mplock();
492 	KASSERT(uio->uio_td == curthread,
493 		("uio_td %p is not td %p", uio->uio_td, curthread));
494 	vp = (struct vnode *)fp->f_data;
495 
496 	ioflag = 0;
497 	if (flags & O_FBLOCKING) {
498 		/* ioflag &= ~IO_NDELAY; */
499 	} else if (flags & O_FNONBLOCKING) {
500 		ioflag |= IO_NDELAY;
501 	} else if (fp->f_flag & FNONBLOCK) {
502 		ioflag |= IO_NDELAY;
503 	}
504 	if (flags & O_FBUFFERED) {
505 		/* ioflag &= ~IO_DIRECT; */
506 	} else if (flags & O_FUNBUFFERED) {
507 		ioflag |= IO_DIRECT;
508 	} else if (fp->f_flag & O_DIRECT) {
509 		ioflag |= IO_DIRECT;
510 	}
511 	vn_lock(vp, LK_SHARED | LK_NOPAUSE | LK_RETRY);
512 	if ((flags & O_FOFFSET) == 0)
513 		uio->uio_offset = fp->f_offset;
514 
515 	ioflag |= sequential_heuristic(uio, fp);
516 
517 	error = VOP_READ(vp, uio, ioflag, cred);
518 	if ((flags & O_FOFFSET) == 0)
519 		fp->f_offset = uio->uio_offset;
520 	fp->f_nextoff = uio->uio_offset;
521 	VOP_UNLOCK(vp, 0);
522 	rel_mplock();
523 	return (error);
524 }
525 
526 /*
527  * Device-optimized file table vnode read routine.
528  *
529  * This bypasses the VOP table and talks directly to the device.  Most
530  * filesystems just route to specfs and can make this optimization.
531  *
532  * MPALMOSTSAFE - acquires mplock
533  */
534 static int
535 svn_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
536 {
537 	struct vnode *vp;
538 	int ioflag;
539 	int error;
540 	dev_t dev;
541 
542 	get_mplock();
543 	KASSERT(uio->uio_td == curthread,
544 		("uio_td %p is not td %p", uio->uio_td, curthread));
545 
546 	vp = (struct vnode *)fp->f_data;
547 	if (vp == NULL || vp->v_type == VBAD) {
548 		error = EBADF;
549 		goto done;
550 	}
551 
552 	if ((dev = vp->v_rdev) == NULL) {
553 		error = EBADF;
554 		goto done;
555 	}
556 	reference_dev(dev);
557 
558 	if (uio->uio_resid == 0) {
559 		error = 0;
560 		goto done;
561 	}
562 	if ((flags & O_FOFFSET) == 0)
563 		uio->uio_offset = fp->f_offset;
564 
565 	ioflag = 0;
566 	if (flags & O_FBLOCKING) {
567 		/* ioflag &= ~IO_NDELAY; */
568 	} else if (flags & O_FNONBLOCKING) {
569 		ioflag |= IO_NDELAY;
570 	} else if (fp->f_flag & FNONBLOCK) {
571 		ioflag |= IO_NDELAY;
572 	}
573 	if (flags & O_FBUFFERED) {
574 		/* ioflag &= ~IO_DIRECT; */
575 	} else if (flags & O_FUNBUFFERED) {
576 		ioflag |= IO_DIRECT;
577 	} else if (fp->f_flag & O_DIRECT) {
578 		ioflag |= IO_DIRECT;
579 	}
580 	ioflag |= sequential_heuristic(uio, fp);
581 
582 	error = dev_dread(dev, uio, ioflag);
583 
584 	release_dev(dev);
585 	if ((flags & O_FOFFSET) == 0)
586 		fp->f_offset = uio->uio_offset;
587 	fp->f_nextoff = uio->uio_offset;
588 done:
589 	rel_mplock();
590 	return (error);
591 }
592 
593 /*
594  * MPALMOSTSAFE - acquires mplock
595  */
596 static int
597 vn_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
598 {
599 	struct vnode *vp;
600 	int error, ioflag;
601 
602 	get_mplock();
603 	KASSERT(uio->uio_td == curthread,
604 		("uio_procp %p is not p %p", uio->uio_td, curthread));
605 	vp = (struct vnode *)fp->f_data;
606 	if (vp->v_type == VREG)
607 		bwillwrite();
608 	vp = (struct vnode *)fp->f_data;	/* XXX needed? */
609 
610 	ioflag = IO_UNIT;
611 	if (vp->v_type == VREG &&
612 	   ((fp->f_flag & O_APPEND) || (flags & O_FAPPEND))) {
613 		ioflag |= IO_APPEND;
614 	}
615 
616 	if (flags & O_FBLOCKING) {
617 		/* ioflag &= ~IO_NDELAY; */
618 	} else if (flags & O_FNONBLOCKING) {
619 		ioflag |= IO_NDELAY;
620 	} else if (fp->f_flag & FNONBLOCK) {
621 		ioflag |= IO_NDELAY;
622 	}
623 	if (flags & O_FBUFFERED) {
624 		/* ioflag &= ~IO_DIRECT; */
625 	} else if (flags & O_FUNBUFFERED) {
626 		ioflag |= IO_DIRECT;
627 	} else if (fp->f_flag & O_DIRECT) {
628 		ioflag |= IO_DIRECT;
629 	}
630 	if (flags & O_FASYNCWRITE) {
631 		/* ioflag &= ~IO_SYNC; */
632 	} else if (flags & O_FSYNCWRITE) {
633 		ioflag |= IO_SYNC;
634 	} else if (fp->f_flag & O_FSYNC) {
635 		ioflag |= IO_SYNC;
636 	}
637 
638 	if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))
639 		ioflag |= IO_SYNC;
640 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
641 	if ((flags & O_FOFFSET) == 0)
642 		uio->uio_offset = fp->f_offset;
643 	ioflag |= sequential_heuristic(uio, fp);
644 	error = VOP_WRITE(vp, uio, ioflag, cred);
645 	if ((flags & O_FOFFSET) == 0)
646 		fp->f_offset = uio->uio_offset;
647 	fp->f_nextoff = uio->uio_offset;
648 	VOP_UNLOCK(vp, 0);
649 	rel_mplock();
650 	return (error);
651 }
652 
653 /*
654  * Device-optimized file table vnode write routine.
655  *
656  * This bypasses the VOP table and talks directly to the device.  Most
657  * filesystems just route to specfs and can make this optimization.
658  *
659  * MPALMOSTSAFE - acquires mplock
660  */
661 static int
662 svn_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
663 {
664 	struct vnode *vp;
665 	int ioflag;
666 	int error;
667 	dev_t dev;
668 
669 	get_mplock();
670 	KASSERT(uio->uio_td == curthread,
671 		("uio_procp %p is not p %p", uio->uio_td, curthread));
672 
673 	vp = (struct vnode *)fp->f_data;
674 	if (vp == NULL || vp->v_type == VBAD) {
675 		error = EBADF;
676 		goto done;
677 	}
678 	if (vp->v_type == VREG)
679 		bwillwrite();
680 	vp = (struct vnode *)fp->f_data;	/* XXX needed? */
681 
682 	if ((dev = vp->v_rdev) == NULL) {
683 		error = EBADF;
684 		goto done;
685 	}
686 	reference_dev(dev);
687 
688 	if ((flags & O_FOFFSET) == 0)
689 		uio->uio_offset = fp->f_offset;
690 
691 	ioflag = IO_UNIT;
692 	if (vp->v_type == VREG &&
693 	   ((fp->f_flag & O_APPEND) || (flags & O_FAPPEND))) {
694 		ioflag |= IO_APPEND;
695 	}
696 
697 	if (flags & O_FBLOCKING) {
698 		/* ioflag &= ~IO_NDELAY; */
699 	} else if (flags & O_FNONBLOCKING) {
700 		ioflag |= IO_NDELAY;
701 	} else if (fp->f_flag & FNONBLOCK) {
702 		ioflag |= IO_NDELAY;
703 	}
704 	if (flags & O_FBUFFERED) {
705 		/* ioflag &= ~IO_DIRECT; */
706 	} else if (flags & O_FUNBUFFERED) {
707 		ioflag |= IO_DIRECT;
708 	} else if (fp->f_flag & O_DIRECT) {
709 		ioflag |= IO_DIRECT;
710 	}
711 	if (flags & O_FASYNCWRITE) {
712 		/* ioflag &= ~IO_SYNC; */
713 	} else if (flags & O_FSYNCWRITE) {
714 		ioflag |= IO_SYNC;
715 	} else if (fp->f_flag & O_FSYNC) {
716 		ioflag |= IO_SYNC;
717 	}
718 
719 	if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))
720 		ioflag |= IO_SYNC;
721 	ioflag |= sequential_heuristic(uio, fp);
722 
723 	error = dev_dwrite(dev, uio, ioflag);
724 
725 	release_dev(dev);
726 	if ((flags & O_FOFFSET) == 0)
727 		fp->f_offset = uio->uio_offset;
728 	fp->f_nextoff = uio->uio_offset;
729 done:
730 	rel_mplock();
731 	return (error);
732 }
733 
734 /*
735  * MPALMOSTSAFE - acquires mplock
736  */
737 static int
738 vn_statfile(struct file *fp, struct stat *sb, struct ucred *cred)
739 {
740 	struct vnode *vp;
741 	int error;
742 
743 	get_mplock();
744 	vp = (struct vnode *)fp->f_data;
745 	error = vn_stat(vp, sb, cred);
746 	rel_mplock();
747 	return (error);
748 }
749 
750 int
751 vn_stat(struct vnode *vp, struct stat *sb, struct ucred *cred)
752 {
753 	struct vattr vattr;
754 	struct vattr *vap;
755 	int error;
756 	u_short mode;
757 	dev_t dev;
758 
759 	vap = &vattr;
760 	error = VOP_GETATTR(vp, vap);
761 	if (error)
762 		return (error);
763 
764 	/*
765 	 * Zero the spare stat fields
766 	 */
767 	sb->st_lspare = 0;
768 	sb->st_qspare = 0;
769 
770 	/*
771 	 * Copy from vattr table
772 	 */
773 	if (vap->va_fsid != VNOVAL)
774 		sb->st_dev = vap->va_fsid;
775 	else
776 		sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0];
777 	sb->st_ino = vap->va_fileid;
778 	mode = vap->va_mode;
779 	switch (vap->va_type) {
780 	case VREG:
781 		mode |= S_IFREG;
782 		break;
783 	case VDIR:
784 		mode |= S_IFDIR;
785 		break;
786 	case VBLK:
787 		mode |= S_IFBLK;
788 		break;
789 	case VCHR:
790 		mode |= S_IFCHR;
791 		break;
792 	case VLNK:
793 		mode |= S_IFLNK;
794 		/* This is a cosmetic change, symlinks do not have a mode. */
795 		if (vp->v_mount->mnt_flag & MNT_NOSYMFOLLOW)
796 			sb->st_mode &= ~ACCESSPERMS;	/* 0000 */
797 		else
798 			sb->st_mode |= ACCESSPERMS;	/* 0777 */
799 		break;
800 	case VSOCK:
801 		mode |= S_IFSOCK;
802 		break;
803 	case VFIFO:
804 		mode |= S_IFIFO;
805 		break;
806 	default:
807 		return (EBADF);
808 	};
809 	sb->st_mode = mode;
810 	sb->st_nlink = vap->va_nlink;
811 	sb->st_uid = vap->va_uid;
812 	sb->st_gid = vap->va_gid;
813 	sb->st_rdev = vap->va_rdev;
814 	sb->st_size = vap->va_size;
815 	sb->st_atimespec = vap->va_atime;
816 	sb->st_mtimespec = vap->va_mtime;
817 	sb->st_ctimespec = vap->va_ctime;
818 
819 	/*
820 	 * A VCHR and VBLK device may track the last access and last modified
821 	 * time independantly of the filesystem.  This is particularly true
822 	 * because device read and write calls may bypass the filesystem.
823 	 */
824 	if (vp->v_type == VCHR || vp->v_type == VBLK) {
825 		if ((dev = vp->v_rdev) != NULL) {
826 			if (dev->si_lastread) {
827 				sb->st_atimespec.tv_sec = dev->si_lastread;
828 				sb->st_atimespec.tv_nsec = 0;
829 			}
830 			if (dev->si_lastwrite) {
831 				sb->st_atimespec.tv_sec = dev->si_lastwrite;
832 				sb->st_atimespec.tv_nsec = 0;
833 			}
834 		}
835 	}
836 
837         /*
838 	 * According to www.opengroup.org, the meaning of st_blksize is
839 	 *   "a filesystem-specific preferred I/O block size for this
840 	 *    object.  In some filesystem types, this may vary from file
841 	 *    to file"
842 	 * Default to PAGE_SIZE after much discussion.
843 	 */
844 
845 	if (vap->va_type == VREG) {
846 		sb->st_blksize = vap->va_blocksize;
847 	} else if (vn_isdisk(vp, NULL)) {
848 		/*
849 		 * XXX this is broken.  If the device is not yet open (aka
850 		 * stat() call, aka v_rdev == NULL), how are we supposed
851 		 * to get a valid block size out of it?
852 		 */
853 		dev_t dev;
854 
855 		if ((dev = vp->v_rdev) == NULL)
856 			dev = udev2dev(vp->v_udev, vp->v_type == VBLK);
857 		sb->st_blksize = dev->si_bsize_best;
858 		if (sb->st_blksize < dev->si_bsize_phys)
859 			sb->st_blksize = dev->si_bsize_phys;
860 		if (sb->st_blksize < BLKDEV_IOSIZE)
861 			sb->st_blksize = BLKDEV_IOSIZE;
862 	} else {
863 		sb->st_blksize = PAGE_SIZE;
864 	}
865 
866 	sb->st_flags = vap->va_flags;
867 	if (suser_cred(cred, 0))
868 		sb->st_gen = 0;
869 	else
870 		sb->st_gen = vap->va_gen;
871 
872 #if (S_BLKSIZE == 512)
873 	/* Optimize this case */
874 	sb->st_blocks = vap->va_bytes >> 9;
875 #else
876 	sb->st_blocks = vap->va_bytes / S_BLKSIZE;
877 #endif
878 	sb->st_fsmid = vap->va_fsmid;
879 	return (0);
880 }
881 
882 /*
883  * MPALMOSTSAFE - acquires mplock
884  */
885 static int
886 vn_ioctl(struct file *fp, u_long com, caddr_t data, struct ucred *ucred)
887 {
888 	struct vnode *vp = ((struct vnode *)fp->f_data);
889 	struct vnode *ovp;
890 	struct vattr vattr;
891 	int error;
892 
893 	get_mplock();
894 
895 	switch (vp->v_type) {
896 	case VREG:
897 	case VDIR:
898 		if (com == FIONREAD) {
899 			if ((error = VOP_GETATTR(vp, &vattr)) != 0)
900 				break;
901 			*(int *)data = vattr.va_size - fp->f_offset;
902 			error = 0;
903 			break;
904 		}
905 		if (com == FIOASYNC) {				/* XXX */
906 			error = 0;				/* XXX */
907 			break;
908 		}
909 		/* fall into ... */
910 	default:
911 #if 0
912 		return (ENOTTY);
913 #endif
914 	case VFIFO:
915 	case VCHR:
916 	case VBLK:
917 		if (com == FIODTYPE) {
918 			if (vp->v_type != VCHR && vp->v_type != VBLK) {
919 				error = ENOTTY;
920 				break;
921 			}
922 			*(int *)data = dev_dflags(vp->v_rdev) & D_TYPEMASK;
923 			error = 0;
924 			break;
925 		}
926 		error = VOP_IOCTL(vp, com, data, fp->f_flag, ucred);
927 		if (error == 0 && com == TIOCSCTTY) {
928 			struct proc *p = curthread->td_proc;
929 			struct session *sess;
930 
931 			if (p == NULL) {
932 				error = ENOTTY;
933 				break;
934 			}
935 
936 			sess = p->p_session;
937 			/* Do nothing if reassigning same control tty */
938 			if (sess->s_ttyvp == vp) {
939 				error = 0;
940 				break;
941 			}
942 
943 			/* Get rid of reference to old control tty */
944 			ovp = sess->s_ttyvp;
945 			vref(vp);
946 			sess->s_ttyvp = vp;
947 			if (ovp)
948 				vrele(ovp);
949 		}
950 		break;
951 	}
952 	rel_mplock();
953 	return (error);
954 }
955 
956 /*
957  * MPALMOSTSAFE - acquires mplock
958  */
959 static int
960 vn_poll(struct file *fp, int events, struct ucred *cred)
961 {
962 	int error;
963 
964 	get_mplock();
965 	error = VOP_POLL(((struct vnode *)fp->f_data), events, cred);
966 	rel_mplock();
967 	return (error);
968 }
969 
970 /*
971  * Check that the vnode is still valid, and if so
972  * acquire requested lock.
973  */
974 int
975 #ifndef	DEBUG_LOCKS
976 vn_lock(struct vnode *vp, int flags)
977 #else
978 debug_vn_lock(struct vnode *vp, int flags, const char *filename, int line)
979 #endif
980 {
981 	int error;
982 
983 	do {
984 #ifdef	DEBUG_LOCKS
985 		vp->filename = filename;
986 		vp->line = line;
987 #endif
988 		error = VOP_LOCK(vp, flags | LK_NOPAUSE);
989 		if (error == 0)
990 			break;
991 	} while (flags & LK_RETRY);
992 
993 	/*
994 	 * Because we (had better!) have a ref on the vnode, once it
995 	 * goes to VRECLAIMED state it will not be recycled until all
996 	 * refs go away.  So we can just check the flag.
997 	 */
998 	if (error == 0 && (vp->v_flag & VRECLAIMED)) {
999 		VOP_UNLOCK(vp, 0);
1000 		error = ENOENT;
1001 	}
1002 	return (error);
1003 }
1004 
1005 /*
1006  * MPALMOSTSAFE - acquires mplock
1007  */
1008 static int
1009 vn_closefile(struct file *fp)
1010 {
1011 	int error;
1012 
1013 	get_mplock();
1014 	fp->f_ops = &badfileops;
1015 	error = vn_close(((struct vnode *)fp->f_data), fp->f_flag);
1016 	rel_mplock();
1017 	return(error);
1018 }
1019 
1020 /*
1021  * MPALMOSTSAFE - acquires mplock
1022  */
1023 static int
1024 vn_kqfilter(struct file *fp, struct knote *kn)
1025 {
1026 	int error;
1027 
1028 	get_mplock();
1029 	error = VOP_KQFILTER(((struct vnode *)fp->f_data), kn);
1030 	rel_mplock();
1031 	return (error);
1032 }
1033