xref: /dragonfly/sys/vfs/devfs/devfs_vnops.c (revision d4ef6694)
1 /*
2  * (MPSAFE)
3  *
4  * Copyright (c) 2009 The DragonFly Project.  All rights reserved.
5  *
6  * This code is derived from software contributed to The DragonFly Project
7  * by Alex Hornung <ahornung@gmail.com>
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
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
17  *    the documentation and/or other materials provided with the
18  *    distribution.
19  * 3. Neither the name of The DragonFly Project nor the names of its
20  *    contributors may be used to endorse or promote products derived
21  *    from this software without specific, prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
26  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
27  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
28  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
29  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
31  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
32  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
33  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/time.h>
39 #include <sys/kernel.h>
40 #include <sys/lock.h>
41 #include <sys/fcntl.h>
42 #include <sys/proc.h>
43 #include <sys/priv.h>
44 #include <sys/signalvar.h>
45 #include <sys/vnode.h>
46 #include <sys/uio.h>
47 #include <sys/mount.h>
48 #include <sys/file.h>
49 #include <sys/namei.h>
50 #include <sys/dirent.h>
51 #include <sys/malloc.h>
52 #include <sys/stat.h>
53 #include <sys/reg.h>
54 #include <vm/vm_pager.h>
55 #include <vm/vm_zone.h>
56 #include <vm/vm_object.h>
57 #include <sys/filio.h>
58 #include <sys/ttycom.h>
59 #include <sys/tty.h>
60 #include <sys/diskslice.h>
61 #include <sys/sysctl.h>
62 #include <sys/devfs.h>
63 #include <sys/pioctl.h>
64 #include <vfs/fifofs/fifo.h>
65 
66 #include <machine/limits.h>
67 
68 #include <sys/buf2.h>
69 #include <sys/sysref2.h>
70 #include <sys/mplock2.h>
71 #include <vm/vm_page2.h>
72 
73 #ifndef SPEC_CHAIN_DEBUG
74 #define SPEC_CHAIN_DEBUG 0
75 #endif
76 
77 MALLOC_DECLARE(M_DEVFS);
78 #define DEVFS_BADOP	(void *)devfs_vop_badop
79 
80 static int devfs_vop_badop(struct vop_generic_args *);
81 static int devfs_vop_access(struct vop_access_args *);
82 static int devfs_vop_inactive(struct vop_inactive_args *);
83 static int devfs_vop_reclaim(struct vop_reclaim_args *);
84 static int devfs_vop_readdir(struct vop_readdir_args *);
85 static int devfs_vop_getattr(struct vop_getattr_args *);
86 static int devfs_vop_setattr(struct vop_setattr_args *);
87 static int devfs_vop_readlink(struct vop_readlink_args *);
88 static int devfs_vop_print(struct vop_print_args *);
89 
90 static int devfs_vop_nresolve(struct vop_nresolve_args *);
91 static int devfs_vop_nlookupdotdot(struct vop_nlookupdotdot_args *);
92 static int devfs_vop_nmkdir(struct vop_nmkdir_args *);
93 static int devfs_vop_nsymlink(struct vop_nsymlink_args *);
94 static int devfs_vop_nrmdir(struct vop_nrmdir_args *);
95 static int devfs_vop_nremove(struct vop_nremove_args *);
96 
97 static int devfs_spec_open(struct vop_open_args *);
98 static int devfs_spec_close(struct vop_close_args *);
99 static int devfs_spec_fsync(struct vop_fsync_args *);
100 
101 static int devfs_spec_read(struct vop_read_args *);
102 static int devfs_spec_write(struct vop_write_args *);
103 static int devfs_spec_ioctl(struct vop_ioctl_args *);
104 static int devfs_spec_kqfilter(struct vop_kqfilter_args *);
105 static int devfs_spec_strategy(struct vop_strategy_args *);
106 static void devfs_spec_strategy_done(struct bio *);
107 static int devfs_spec_freeblks(struct vop_freeblks_args *);
108 static int devfs_spec_bmap(struct vop_bmap_args *);
109 static int devfs_spec_advlock(struct vop_advlock_args *);
110 static void devfs_spec_getpages_iodone(struct bio *);
111 static int devfs_spec_getpages(struct vop_getpages_args *);
112 
113 static int devfs_fo_close(struct file *);
114 static int devfs_fo_read(struct file *, struct uio *, struct ucred *, int);
115 static int devfs_fo_write(struct file *, struct uio *, struct ucred *, int);
116 static int devfs_fo_stat(struct file *, struct stat *, struct ucred *);
117 static int devfs_fo_kqfilter(struct file *, struct knote *);
118 static int devfs_fo_ioctl(struct file *, u_long, caddr_t,
119 				struct ucred *, struct sysmsg *);
120 static __inline int sequential_heuristic(struct uio *, struct file *);
121 
122 extern struct lock devfs_lock;
123 
124 /*
125  * devfs vnode operations for regular files.  All vnode ops are MPSAFE.
126  */
127 struct vop_ops devfs_vnode_norm_vops = {
128 	.vop_default =		vop_defaultop,
129 	.vop_access =		devfs_vop_access,
130 	.vop_advlock =		DEVFS_BADOP,
131 	.vop_bmap =		DEVFS_BADOP,
132 	.vop_close =		vop_stdclose,
133 	.vop_getattr =		devfs_vop_getattr,
134 	.vop_inactive =		devfs_vop_inactive,
135 	.vop_ncreate =		DEVFS_BADOP,
136 	.vop_nresolve =		devfs_vop_nresolve,
137 	.vop_nlookupdotdot =	devfs_vop_nlookupdotdot,
138 	.vop_nlink =		DEVFS_BADOP,
139 	.vop_nmkdir =		devfs_vop_nmkdir,
140 	.vop_nmknod =		DEVFS_BADOP,
141 	.vop_nremove =		devfs_vop_nremove,
142 	.vop_nrename =		DEVFS_BADOP,
143 	.vop_nrmdir =		devfs_vop_nrmdir,
144 	.vop_nsymlink =		devfs_vop_nsymlink,
145 	.vop_open =		vop_stdopen,
146 	.vop_pathconf =		vop_stdpathconf,
147 	.vop_print =		devfs_vop_print,
148 	.vop_read =		DEVFS_BADOP,
149 	.vop_readdir =		devfs_vop_readdir,
150 	.vop_readlink =		devfs_vop_readlink,
151 	.vop_reclaim =		devfs_vop_reclaim,
152 	.vop_setattr =		devfs_vop_setattr,
153 	.vop_write =		DEVFS_BADOP,
154 	.vop_ioctl =		DEVFS_BADOP
155 };
156 
157 /*
158  * devfs vnode operations for character devices.  All vnode ops are MPSAFE.
159  */
160 struct vop_ops devfs_vnode_dev_vops = {
161 	.vop_default =		vop_defaultop,
162 	.vop_access =		devfs_vop_access,
163 	.vop_advlock =		devfs_spec_advlock,
164 	.vop_bmap =		devfs_spec_bmap,
165 	.vop_close =		devfs_spec_close,
166 	.vop_freeblks =		devfs_spec_freeblks,
167 	.vop_fsync =		devfs_spec_fsync,
168 	.vop_getattr =		devfs_vop_getattr,
169 	.vop_getpages =		devfs_spec_getpages,
170 	.vop_inactive =		devfs_vop_inactive,
171 	.vop_open =		devfs_spec_open,
172 	.vop_pathconf =		vop_stdpathconf,
173 	.vop_print =		devfs_vop_print,
174 	.vop_kqfilter =		devfs_spec_kqfilter,
175 	.vop_read =		devfs_spec_read,
176 	.vop_readdir =		DEVFS_BADOP,
177 	.vop_readlink =		DEVFS_BADOP,
178 	.vop_reclaim =		devfs_vop_reclaim,
179 	.vop_setattr =		devfs_vop_setattr,
180 	.vop_strategy =		devfs_spec_strategy,
181 	.vop_write =		devfs_spec_write,
182 	.vop_ioctl =		devfs_spec_ioctl
183 };
184 
185 /*
186  * devfs file pointer operations.  All fileops are MPSAFE.
187  */
188 struct vop_ops *devfs_vnode_dev_vops_p = &devfs_vnode_dev_vops;
189 
190 struct fileops devfs_dev_fileops = {
191 	.fo_read	= devfs_fo_read,
192 	.fo_write	= devfs_fo_write,
193 	.fo_ioctl	= devfs_fo_ioctl,
194 	.fo_kqfilter	= devfs_fo_kqfilter,
195 	.fo_stat	= devfs_fo_stat,
196 	.fo_close	= devfs_fo_close,
197 	.fo_shutdown	= nofo_shutdown
198 };
199 
200 /*
201  * These two functions are possibly temporary hacks for devices (aka
202  * the pty code) which want to control the node attributes themselves.
203  *
204  * XXX we may ultimately desire to simply remove the uid/gid/mode
205  * from the node entirely.
206  *
207  * MPSAFE - sorta.  Theoretically the overwrite can compete since they
208  *	    are loading from the same fields.
209  */
210 static __inline void
211 node_sync_dev_get(struct devfs_node *node)
212 {
213 	cdev_t dev;
214 
215 	if ((dev = node->d_dev) && (dev->si_flags & SI_OVERRIDE)) {
216 		node->uid = dev->si_uid;
217 		node->gid = dev->si_gid;
218 		node->mode = dev->si_perms;
219 	}
220 }
221 
222 static __inline void
223 node_sync_dev_set(struct devfs_node *node)
224 {
225 	cdev_t dev;
226 
227 	if ((dev = node->d_dev) && (dev->si_flags & SI_OVERRIDE)) {
228 		dev->si_uid = node->uid;
229 		dev->si_gid = node->gid;
230 		dev->si_perms = node->mode;
231 	}
232 }
233 
234 /*
235  * generic entry point for unsupported operations
236  */
237 static int
238 devfs_vop_badop(struct vop_generic_args *ap)
239 {
240 	return (EIO);
241 }
242 
243 
244 static int
245 devfs_vop_access(struct vop_access_args *ap)
246 {
247 	struct devfs_node *node = DEVFS_NODE(ap->a_vp);
248 	int error;
249 
250 	if (!devfs_node_is_accessible(node))
251 		return ENOENT;
252 	node_sync_dev_get(node);
253 	error = vop_helper_access(ap, node->uid, node->gid,
254 				  node->mode, node->flags);
255 
256 	return error;
257 }
258 
259 
260 static int
261 devfs_vop_inactive(struct vop_inactive_args *ap)
262 {
263 	struct devfs_node *node = DEVFS_NODE(ap->a_vp);
264 
265 	if (node == NULL || (node->flags & DEVFS_NODE_LINKED) == 0)
266 		vrecycle(ap->a_vp);
267 	return 0;
268 }
269 
270 
271 static int
272 devfs_vop_reclaim(struct vop_reclaim_args *ap)
273 {
274 	struct devfs_node *node;
275 	struct vnode *vp;
276 	int locked;
277 
278 	/*
279 	 * Check if it is locked already. if not, we acquire the devfs lock
280 	 */
281 	if ((lockstatus(&devfs_lock, curthread)) != LK_EXCLUSIVE) {
282 		lockmgr(&devfs_lock, LK_EXCLUSIVE);
283 		locked = 1;
284 	} else {
285 		locked = 0;
286 	}
287 
288 	/*
289 	 * Get rid of the devfs_node if it is no longer linked into the
290 	 * topology.
291 	 */
292 	vp = ap->a_vp;
293 	if ((node = DEVFS_NODE(vp)) != NULL) {
294 		node->v_node = NULL;
295 		if ((node->flags & DEVFS_NODE_LINKED) == 0)
296 			devfs_freep(node);
297 	}
298 
299 	if (locked)
300 		lockmgr(&devfs_lock, LK_RELEASE);
301 
302 	/*
303 	 * v_rdev needs to be properly released using v_release_rdev
304 	 * Make sure v_data is NULL as well.
305 	 */
306 	vp->v_data = NULL;
307 	v_release_rdev(vp);
308 	return 0;
309 }
310 
311 
312 static int
313 devfs_vop_readdir(struct vop_readdir_args *ap)
314 {
315 	struct devfs_node *dnode = DEVFS_NODE(ap->a_vp);
316 	struct devfs_node *node;
317 	int cookie_index;
318 	int ncookies;
319 	int error2;
320 	int error;
321 	int r;
322 	off_t *cookies;
323 	off_t saveoff;
324 
325 	devfs_debug(DEVFS_DEBUG_DEBUG, "devfs_readdir() called!\n");
326 
327 	if (ap->a_uio->uio_offset < 0 || ap->a_uio->uio_offset > INT_MAX)
328 		return (EINVAL);
329 	error = vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY | LK_FAILRECLAIM);
330 	if (error)
331 		return (error);
332 
333 	if (!devfs_node_is_accessible(dnode)) {
334 		vn_unlock(ap->a_vp);
335 		return ENOENT;
336 	}
337 
338 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
339 
340 	saveoff = ap->a_uio->uio_offset;
341 
342 	if (ap->a_ncookies) {
343 		ncookies = ap->a_uio->uio_resid / 16 + 1; /* Why / 16 ?? */
344 		if (ncookies > 256)
345 			ncookies = 256;
346 		cookies = kmalloc(256 * sizeof(off_t), M_TEMP, M_WAITOK);
347 		cookie_index = 0;
348 	} else {
349 		ncookies = -1;
350 		cookies = NULL;
351 		cookie_index = 0;
352 	}
353 
354 	nanotime(&dnode->atime);
355 
356 	if (saveoff == 0) {
357 		r = vop_write_dirent(&error, ap->a_uio, dnode->d_dir.d_ino,
358 				     DT_DIR, 1, ".");
359 		if (r)
360 			goto done;
361 		if (cookies)
362 			cookies[cookie_index] = saveoff;
363 		saveoff++;
364 		cookie_index++;
365 		if (cookie_index == ncookies)
366 			goto done;
367 	}
368 
369 	if (saveoff == 1) {
370 		if (dnode->parent) {
371 			r = vop_write_dirent(&error, ap->a_uio,
372 					     dnode->parent->d_dir.d_ino,
373 					     DT_DIR, 2, "..");
374 		} else {
375 			r = vop_write_dirent(&error, ap->a_uio,
376 					     dnode->d_dir.d_ino,
377 					     DT_DIR, 2, "..");
378 		}
379 		if (r)
380 			goto done;
381 		if (cookies)
382 			cookies[cookie_index] = saveoff;
383 		saveoff++;
384 		cookie_index++;
385 		if (cookie_index == ncookies)
386 			goto done;
387 	}
388 
389 	TAILQ_FOREACH(node, DEVFS_DENODE_HEAD(dnode), link) {
390 		if ((node->flags & DEVFS_HIDDEN) ||
391 		    (node->flags & DEVFS_INVISIBLE)) {
392 			continue;
393 		}
394 
395 		/*
396 		 * If the node type is a valid devfs alias, then we make
397 		 * sure that the target isn't hidden. If it is, we don't
398 		 * show the link in the directory listing.
399 		 */
400 		if ((node->node_type == Nlink) && (node->link_target != NULL) &&
401 			(node->link_target->flags & DEVFS_HIDDEN))
402 			continue;
403 
404 		if (node->cookie < saveoff)
405 			continue;
406 
407 		saveoff = node->cookie;
408 
409 		error2 = vop_write_dirent(&error, ap->a_uio, node->d_dir.d_ino,
410 					  node->d_dir.d_type,
411 					  node->d_dir.d_namlen,
412 					  node->d_dir.d_name);
413 
414 		if (error2)
415 			break;
416 
417 		saveoff++;
418 
419 		if (cookies)
420 			cookies[cookie_index] = node->cookie;
421 		++cookie_index;
422 		if (cookie_index == ncookies)
423 			break;
424 	}
425 
426 done:
427 	lockmgr(&devfs_lock, LK_RELEASE);
428 	vn_unlock(ap->a_vp);
429 
430 	ap->a_uio->uio_offset = saveoff;
431 	if (error && cookie_index == 0) {
432 		if (cookies) {
433 			kfree(cookies, M_TEMP);
434 			*ap->a_ncookies = 0;
435 			*ap->a_cookies = NULL;
436 		}
437 	} else {
438 		if (cookies) {
439 			*ap->a_ncookies = cookie_index;
440 			*ap->a_cookies = cookies;
441 		}
442 	}
443 	return (error);
444 }
445 
446 
447 static int
448 devfs_vop_nresolve(struct vop_nresolve_args *ap)
449 {
450 	struct devfs_node *dnode = DEVFS_NODE(ap->a_dvp);
451 	struct devfs_node *node, *found = NULL;
452 	struct namecache *ncp;
453 	struct vnode *vp = NULL;
454 	int error = 0;
455 	int len;
456 	int depth;
457 
458 	ncp = ap->a_nch->ncp;
459 	len = ncp->nc_nlen;
460 
461 	if (!devfs_node_is_accessible(dnode))
462 		return ENOENT;
463 
464 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
465 
466 	if ((dnode->node_type != Nroot) && (dnode->node_type != Ndir)) {
467 		error = ENOENT;
468 		cache_setvp(ap->a_nch, NULL);
469 		goto out;
470 	}
471 
472 	TAILQ_FOREACH(node, DEVFS_DENODE_HEAD(dnode), link) {
473 		if (len == node->d_dir.d_namlen) {
474 			if (!memcmp(ncp->nc_name, node->d_dir.d_name, len)) {
475 				found = node;
476 				break;
477 			}
478 		}
479 	}
480 
481 	if (found) {
482 		depth = 0;
483 		while ((found->node_type == Nlink) && (found->link_target)) {
484 			if (depth >= 8) {
485 				devfs_debug(DEVFS_DEBUG_SHOW, "Recursive link or depth >= 8");
486 				break;
487 			}
488 
489 			found = found->link_target;
490 			++depth;
491 		}
492 
493 		if (!(found->flags & DEVFS_HIDDEN))
494 			devfs_allocv(/*ap->a_dvp->v_mount, */ &vp, found);
495 	}
496 
497 	if (vp == NULL) {
498 		error = ENOENT;
499 		cache_setvp(ap->a_nch, NULL);
500 		goto out;
501 
502 	}
503 	KKASSERT(vp);
504 	vn_unlock(vp);
505 	cache_setvp(ap->a_nch, vp);
506 	vrele(vp);
507 out:
508 	lockmgr(&devfs_lock, LK_RELEASE);
509 
510 	return error;
511 }
512 
513 
514 static int
515 devfs_vop_nlookupdotdot(struct vop_nlookupdotdot_args *ap)
516 {
517 	struct devfs_node *dnode = DEVFS_NODE(ap->a_dvp);
518 
519 	*ap->a_vpp = NULL;
520 	if (!devfs_node_is_accessible(dnode))
521 		return ENOENT;
522 
523 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
524 	if (dnode->parent != NULL) {
525 		devfs_allocv(ap->a_vpp, dnode->parent);
526 		vn_unlock(*ap->a_vpp);
527 	}
528 	lockmgr(&devfs_lock, LK_RELEASE);
529 
530 	return ((*ap->a_vpp == NULL) ? ENOENT : 0);
531 }
532 
533 
534 static int
535 devfs_vop_getattr(struct vop_getattr_args *ap)
536 {
537 	struct devfs_node *node = DEVFS_NODE(ap->a_vp);
538 	struct vattr *vap = ap->a_vap;
539 	struct partinfo pinfo;
540 	int error = 0;
541 
542 #if 0
543 	if (!devfs_node_is_accessible(node))
544 		return ENOENT;
545 #endif
546 	node_sync_dev_get(node);
547 
548 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
549 
550 	/* start by zeroing out the attributes */
551 	VATTR_NULL(vap);
552 
553 	/* next do all the common fields */
554 	vap->va_type = ap->a_vp->v_type;
555 	vap->va_mode = node->mode;
556 	vap->va_fileid = DEVFS_NODE(ap->a_vp)->d_dir.d_ino ;
557 	vap->va_flags = 0;
558 	vap->va_blocksize = DEV_BSIZE;
559 	vap->va_bytes = vap->va_size = 0;
560 
561 	vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
562 
563 	vap->va_atime = node->atime;
564 	vap->va_mtime = node->mtime;
565 	vap->va_ctime = node->ctime;
566 
567 	vap->va_nlink = 1; /* number of references to file */
568 
569 	vap->va_uid = node->uid;
570 	vap->va_gid = node->gid;
571 
572 	vap->va_rmajor = 0;
573 	vap->va_rminor = 0;
574 
575 	if ((node->node_type == Ndev) && node->d_dev)  {
576 		reference_dev(node->d_dev);
577 		vap->va_rminor = node->d_dev->si_uminor;
578 		release_dev(node->d_dev);
579 	}
580 
581 	/* For a softlink the va_size is the length of the softlink */
582 	if (node->symlink_name != 0) {
583 		vap->va_bytes = vap->va_size = node->symlink_namelen;
584 	}
585 
586 	/*
587 	 * For a disk-type device, va_size is the size of the underlying
588 	 * device, so that lseek() works properly.
589 	 */
590 	if ((node->d_dev) && (dev_dflags(node->d_dev) & D_DISK)) {
591 		bzero(&pinfo, sizeof(pinfo));
592 		error = dev_dioctl(node->d_dev, DIOCGPART, (void *)&pinfo,
593 				   0, proc0.p_ucred, NULL, NULL);
594 		if ((error == 0) && (pinfo.media_blksize != 0)) {
595 			vap->va_size = pinfo.media_size;
596 		} else {
597 			vap->va_size = 0;
598 			error = 0;
599 		}
600 	}
601 
602 	lockmgr(&devfs_lock, LK_RELEASE);
603 
604 	return (error);
605 }
606 
607 
608 static int
609 devfs_vop_setattr(struct vop_setattr_args *ap)
610 {
611 	struct devfs_node *node = DEVFS_NODE(ap->a_vp);
612 	struct vattr *vap;
613 	uid_t cur_uid;
614 	gid_t cur_gid;
615 	mode_t cur_mode;
616 	int error = 0;
617 
618 	if (!devfs_node_is_accessible(node))
619 		return ENOENT;
620 	node_sync_dev_get(node);
621 
622 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
623 
624 	vap = ap->a_vap;
625 
626 	if ((vap->va_uid != (uid_t)VNOVAL) || (vap->va_gid != (gid_t)VNOVAL)) {
627 		cur_uid = node->uid;
628 		cur_gid = node->gid;
629 		cur_mode = node->mode;
630 		error = vop_helper_chown(ap->a_vp, vap->va_uid, vap->va_gid,
631 		    ap->a_cred, &cur_uid, &cur_gid, &cur_mode);
632 		if (error)
633 			goto out;
634 
635 		if (node->uid != cur_uid || node->gid != cur_gid) {
636 			node->uid = cur_uid;
637 			node->gid = cur_gid;
638 			node->mode = cur_mode;
639 		}
640 	}
641 
642 	if (vap->va_mode != (mode_t)VNOVAL) {
643 		cur_mode = node->mode;
644 		error = vop_helper_chmod(ap->a_vp, vap->va_mode, ap->a_cred,
645 		    node->uid, node->gid, &cur_mode);
646 		if (error == 0 && node->mode != cur_mode) {
647 			node->mode = cur_mode;
648 		}
649 	}
650 
651 out:
652 	node_sync_dev_set(node);
653 	nanotime(&node->ctime);
654 	lockmgr(&devfs_lock, LK_RELEASE);
655 
656 	return error;
657 }
658 
659 
660 static int
661 devfs_vop_readlink(struct vop_readlink_args *ap)
662 {
663 	struct devfs_node *node = DEVFS_NODE(ap->a_vp);
664 	int ret;
665 
666 	if (!devfs_node_is_accessible(node))
667 		return ENOENT;
668 
669 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
670 	ret = uiomove(node->symlink_name, node->symlink_namelen, ap->a_uio);
671 	lockmgr(&devfs_lock, LK_RELEASE);
672 
673 	return ret;
674 }
675 
676 
677 static int
678 devfs_vop_print(struct vop_print_args *ap)
679 {
680 	return (0);
681 }
682 
683 static int
684 devfs_vop_nmkdir(struct vop_nmkdir_args *ap)
685 {
686 	struct devfs_node *dnode = DEVFS_NODE(ap->a_dvp);
687 	struct devfs_node *node;
688 
689 	if (!devfs_node_is_accessible(dnode))
690 		return ENOENT;
691 
692 	if ((dnode->node_type != Nroot) && (dnode->node_type != Ndir))
693 		goto out;
694 
695 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
696 	devfs_allocvp(ap->a_dvp->v_mount, ap->a_vpp, Ndir,
697 		      ap->a_nch->ncp->nc_name, dnode, NULL);
698 
699 	if (*ap->a_vpp) {
700 		node = DEVFS_NODE(*ap->a_vpp);
701 		node->flags |= DEVFS_USER_CREATED;
702 		cache_setunresolved(ap->a_nch);
703 		cache_setvp(ap->a_nch, *ap->a_vpp);
704 	}
705 	lockmgr(&devfs_lock, LK_RELEASE);
706 out:
707 	return ((*ap->a_vpp == NULL) ? ENOTDIR : 0);
708 }
709 
710 static int
711 devfs_vop_nsymlink(struct vop_nsymlink_args *ap)
712 {
713 	struct devfs_node *dnode = DEVFS_NODE(ap->a_dvp);
714 	struct devfs_node *node;
715 	size_t targetlen;
716 
717 	if (!devfs_node_is_accessible(dnode))
718 		return ENOENT;
719 
720 	ap->a_vap->va_type = VLNK;
721 
722 	if ((dnode->node_type != Nroot) && (dnode->node_type != Ndir))
723 		goto out;
724 
725 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
726 	devfs_allocvp(ap->a_dvp->v_mount, ap->a_vpp, Nlink,
727 		      ap->a_nch->ncp->nc_name, dnode, NULL);
728 
729 	targetlen = strlen(ap->a_target);
730 	if (*ap->a_vpp) {
731 		node = DEVFS_NODE(*ap->a_vpp);
732 		node->flags |= DEVFS_USER_CREATED;
733 		node->symlink_namelen = targetlen;
734 		node->symlink_name = kmalloc(targetlen + 1, M_DEVFS, M_WAITOK);
735 		memcpy(node->symlink_name, ap->a_target, targetlen);
736 		node->symlink_name[targetlen] = '\0';
737 		cache_setunresolved(ap->a_nch);
738 		cache_setvp(ap->a_nch, *ap->a_vpp);
739 	}
740 	lockmgr(&devfs_lock, LK_RELEASE);
741 out:
742 	return ((*ap->a_vpp == NULL) ? ENOTDIR : 0);
743 }
744 
745 static int
746 devfs_vop_nrmdir(struct vop_nrmdir_args *ap)
747 {
748 	struct devfs_node *dnode = DEVFS_NODE(ap->a_dvp);
749 	struct devfs_node *node;
750 	struct namecache *ncp;
751 	int error = ENOENT;
752 
753 	ncp = ap->a_nch->ncp;
754 
755 	if (!devfs_node_is_accessible(dnode))
756 		return ENOENT;
757 
758 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
759 
760 	if ((dnode->node_type != Nroot) && (dnode->node_type != Ndir))
761 		goto out;
762 
763 	TAILQ_FOREACH(node, DEVFS_DENODE_HEAD(dnode), link) {
764 		if (ncp->nc_nlen != node->d_dir.d_namlen)
765 			continue;
766 		if (memcmp(ncp->nc_name, node->d_dir.d_name, ncp->nc_nlen))
767 			continue;
768 
769 		/*
770 		 * only allow removal of user created dirs
771 		 */
772 		if ((node->flags & DEVFS_USER_CREATED) == 0) {
773 			error = EPERM;
774 			goto out;
775 		} else if (node->node_type != Ndir) {
776 			error = ENOTDIR;
777 			goto out;
778 		} else if (node->nchildren > 2) {
779 			error = ENOTEMPTY;
780 			goto out;
781 		} else {
782 			if (node->v_node)
783 				cache_inval_vp(node->v_node, CINV_DESTROY);
784 			devfs_unlinkp(node);
785 			error = 0;
786 			break;
787 		}
788 	}
789 
790 	cache_unlink(ap->a_nch);
791 out:
792 	lockmgr(&devfs_lock, LK_RELEASE);
793 	return error;
794 }
795 
796 static int
797 devfs_vop_nremove(struct vop_nremove_args *ap)
798 {
799 	struct devfs_node *dnode = DEVFS_NODE(ap->a_dvp);
800 	struct devfs_node *node;
801 	struct namecache *ncp;
802 	int error = ENOENT;
803 
804 	ncp = ap->a_nch->ncp;
805 
806 	if (!devfs_node_is_accessible(dnode))
807 		return ENOENT;
808 
809 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
810 
811 	if ((dnode->node_type != Nroot) && (dnode->node_type != Ndir))
812 		goto out;
813 
814 	TAILQ_FOREACH(node, DEVFS_DENODE_HEAD(dnode), link) {
815 		if (ncp->nc_nlen != node->d_dir.d_namlen)
816 			continue;
817 		if (memcmp(ncp->nc_name, node->d_dir.d_name, ncp->nc_nlen))
818 			continue;
819 
820 		/*
821 		 * only allow removal of user created stuff (e.g. symlinks)
822 		 */
823 		if ((node->flags & DEVFS_USER_CREATED) == 0) {
824 			error = EPERM;
825 			goto out;
826 		} else if (node->node_type == Ndir) {
827 			error = EISDIR;
828 			goto out;
829 		} else {
830 			if (node->v_node)
831 				cache_inval_vp(node->v_node, CINV_DESTROY);
832 			devfs_unlinkp(node);
833 			error = 0;
834 			break;
835 		}
836 	}
837 
838 	cache_unlink(ap->a_nch);
839 out:
840 	lockmgr(&devfs_lock, LK_RELEASE);
841 	return error;
842 }
843 
844 
845 static int
846 devfs_spec_open(struct vop_open_args *ap)
847 {
848 	struct vnode *vp = ap->a_vp;
849 	struct vnode *orig_vp = NULL;
850 	struct devfs_node *node = DEVFS_NODE(vp);
851 	struct devfs_node *newnode;
852 	cdev_t dev, ndev = NULL;
853 	int error = 0;
854 
855 	if (node) {
856 		if (node->d_dev == NULL)
857 			return ENXIO;
858 		if (!devfs_node_is_accessible(node))
859 			return ENOENT;
860 	}
861 
862 	if ((dev = vp->v_rdev) == NULL)
863 		return ENXIO;
864 
865 	vn_lock(vp, LK_UPGRADE | LK_RETRY);
866 
867 	if (node && ap->a_fp) {
868 		devfs_debug(DEVFS_DEBUG_DEBUG, "devfs_spec_open: -1.1-\n");
869 		lockmgr(&devfs_lock, LK_EXCLUSIVE);
870 
871 		ndev = devfs_clone(dev, node->d_dir.d_name,
872 				   node->d_dir.d_namlen,
873 				   ap->a_mode, ap->a_cred);
874 		if (ndev != NULL) {
875 			newnode = devfs_create_device_node(
876 					DEVFS_MNTDATA(vp->v_mount)->root_node,
877 					ndev, NULL, NULL);
878 			/* XXX: possibly destroy device if this happens */
879 
880 			if (newnode != NULL) {
881 				dev = ndev;
882 				devfs_link_dev(dev);
883 
884 				devfs_debug(DEVFS_DEBUG_DEBUG,
885 						"parent here is: %s, node is: |%s|\n",
886 						((node->parent->node_type == Nroot) ?
887 						"ROOT!" : node->parent->d_dir.d_name),
888 						newnode->d_dir.d_name);
889 				devfs_debug(DEVFS_DEBUG_DEBUG,
890 						"test: %s\n",
891 						((struct devfs_node *)(TAILQ_LAST(DEVFS_DENODE_HEAD(node->parent), devfs_node_head)))->d_dir.d_name);
892 
893 				/*
894 				 * orig_vp is set to the original vp if we cloned.
895 				 */
896 				/* node->flags |= DEVFS_CLONED; */
897 				devfs_allocv(&vp, newnode);
898 				orig_vp = ap->a_vp;
899 				ap->a_vp = vp;
900 			}
901 		}
902 		lockmgr(&devfs_lock, LK_RELEASE);
903 		/*
904 		 * Synchronize devfs here to make sure that, if the cloned device
905 		 * creates other device nodes in addition to the cloned one,
906 		 * all of them are created by the time we return from opening
907 		 * the cloned one.
908 		 */
909 		if (ndev)
910 			devfs_config();
911 	}
912 
913 	devfs_debug(DEVFS_DEBUG_DEBUG,
914 		    "devfs_spec_open() called on %s! \n",
915 		    dev->si_name);
916 
917 	/*
918 	 * Make this field valid before any I/O in ->d_open
919 	 */
920 	if (!dev->si_iosize_max)
921 		/* XXX: old DFLTPHYS == 64KB dependency */
922 		dev->si_iosize_max = min(MAXPHYS,64*1024);
923 
924 	if (dev_dflags(dev) & D_TTY)
925 		vsetflags(vp, VISTTY);
926 
927 	/*
928 	 * Open underlying device
929 	 */
930 	vn_unlock(vp);
931 	error = dev_dopen(dev, ap->a_mode, S_IFCHR, ap->a_cred, ap->a_fp);
932 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
933 
934 	/*
935 	 * Clean up any cloned vp if we error out.
936 	 */
937 	if (error) {
938 		if (orig_vp) {
939 			vput(vp);
940 			ap->a_vp = orig_vp;
941 			/* orig_vp = NULL; */
942 		}
943 		return error;
944 	}
945 
946 	/*
947 	 * This checks if the disk device is going to be opened for writing.
948 	 * It will be only allowed in the cases where securelevel permits it
949 	 * and it's not mounted R/W.
950 	 */
951 	if ((dev_dflags(dev) & D_DISK) && (ap->a_mode & FWRITE) &&
952 	    (ap->a_cred != FSCRED)) {
953 
954 		/* Very secure mode. No open for writing allowed */
955 		if (securelevel >= 2)
956 			return EPERM;
957 
958 		/*
959 		 * If it is mounted R/W, do not allow to open for writing.
960 		 * In the case it's mounted read-only but securelevel
961 		 * is >= 1, then do not allow opening for writing either.
962 		 */
963 		if (vfs_mountedon(vp)) {
964 			if (!(dev->si_mountpoint->mnt_flag & MNT_RDONLY))
965 				return EBUSY;
966 			else if (securelevel >= 1)
967 				return EPERM;
968 		}
969 	}
970 
971 	if (dev_dflags(dev) & D_TTY) {
972 		if (dev->si_tty) {
973 			struct tty *tp;
974 			tp = dev->si_tty;
975 			if (!tp->t_stop) {
976 				devfs_debug(DEVFS_DEBUG_DEBUG,
977 					    "devfs: no t_stop\n");
978 				tp->t_stop = nottystop;
979 			}
980 		}
981 	}
982 
983 
984 	if (vn_isdisk(vp, NULL)) {
985 		if (!dev->si_bsize_phys)
986 			dev->si_bsize_phys = DEV_BSIZE;
987 		vinitvmio(vp, IDX_TO_OFF(INT_MAX), PAGE_SIZE, -1);
988 	}
989 
990 	vop_stdopen(ap);
991 #if 0
992 	if (node)
993 		nanotime(&node->atime);
994 #endif
995 
996 	/*
997 	 * If we replaced the vp the vop_stdopen() call will have loaded
998 	 * it into fp->f_data and vref()d the vp, giving us two refs.  So
999 	 * instead of just unlocking it here we have to vput() it.
1000 	 */
1001 	if (orig_vp)
1002 		vput(vp);
1003 
1004 	/* Ugly pty magic, to make pty devices appear once they are opened */
1005 	if (node && (node->flags & DEVFS_PTY) == DEVFS_PTY)
1006 		node->flags &= ~DEVFS_INVISIBLE;
1007 
1008 	if (ap->a_fp) {
1009 		KKASSERT(ap->a_fp->f_type == DTYPE_VNODE);
1010 		KKASSERT((ap->a_fp->f_flag & FMASK) == (ap->a_mode & FMASK));
1011 		ap->a_fp->f_ops = &devfs_dev_fileops;
1012 		KKASSERT(ap->a_fp->f_data == (void *)vp);
1013 	}
1014 
1015 	return 0;
1016 }
1017 
1018 static int
1019 devfs_spec_close(struct vop_close_args *ap)
1020 {
1021 	struct devfs_node *node;
1022 	struct proc *p = curproc;
1023 	struct vnode *vp = ap->a_vp;
1024 	cdev_t dev = vp->v_rdev;
1025 	int error = 0;
1026 	int needrelock;
1027 	int opencount;
1028 
1029 	/*
1030 	 * We do special tests on the opencount so unfortunately we need
1031 	 * an exclusive lock.
1032 	 */
1033 	vn_lock(vp, LK_UPGRADE | LK_RETRY);
1034 
1035 	if (dev)
1036 		devfs_debug(DEVFS_DEBUG_DEBUG,
1037 			    "devfs_spec_close() called on %s! \n",
1038 			    dev->si_name);
1039 	else
1040 		devfs_debug(DEVFS_DEBUG_DEBUG,
1041 			    "devfs_spec_close() called, null vode!\n");
1042 
1043 	/*
1044 	 * A couple of hacks for devices and tty devices.  The
1045 	 * vnode ref count cannot be used to figure out the
1046 	 * last close, but we can use v_opencount now that
1047 	 * revoke works properly.
1048 	 *
1049 	 * Detect the last close on a controlling terminal and clear
1050 	 * the session (half-close).
1051 	 *
1052 	 * XXX opencount is not SMP safe.  The vnode is locked but there
1053 	 *     may be multiple vnodes referencing the same device.
1054 	 */
1055 	if (dev) {
1056 		/*
1057 		 * NOTE: Try to avoid global tokens when testing opencount
1058 		 * XXX hack, fixme. needs a struct lock and opencount in
1059 		 * struct cdev itself.
1060 		 */
1061 		reference_dev(dev);
1062 		opencount = vp->v_opencount;
1063 		if (opencount <= 1)
1064 			opencount = count_dev(dev);   /* XXX NOT SMP SAFE */
1065 	} else {
1066 		opencount = 0;
1067 	}
1068 
1069 	if (p && vp->v_opencount <= 1 && vp == p->p_session->s_ttyvp) {
1070 		p->p_session->s_ttyvp = NULL;
1071 		vrele(vp);
1072 	}
1073 
1074 	/*
1075 	 * Vnodes can be opened and closed multiple times.  Do not really
1076 	 * close the device unless (1) it is being closed forcibly,
1077 	 * (2) the device wants to track closes, or (3) this is the last
1078 	 * vnode doing its last close on the device.
1079 	 *
1080 	 * XXX the VXLOCK (force close) case can leave vnodes referencing
1081 	 * a closed device.  This might not occur now that our revoke is
1082 	 * fixed.
1083 	 */
1084 	devfs_debug(DEVFS_DEBUG_DEBUG, "devfs_spec_close() -1- \n");
1085 	if (dev && ((vp->v_flag & VRECLAIMED) ||
1086 	    (dev_dflags(dev) & D_TRACKCLOSE) ||
1087 	    (opencount == 1))) {
1088 		/*
1089 		 * Ugly pty magic, to make pty devices disappear again once
1090 		 * they are closed.
1091 		 */
1092 		node = DEVFS_NODE(ap->a_vp);
1093 		if (node && (node->flags & DEVFS_PTY))
1094 			node->flags |= DEVFS_INVISIBLE;
1095 
1096 		/*
1097 		 * Unlock around dev_dclose(), unless the vnode is
1098 		 * undergoing a vgone/reclaim (during umount).
1099 		 */
1100 		needrelock = 0;
1101 		if ((vp->v_flag & VRECLAIMED) == 0 && vn_islocked(vp)) {
1102 			needrelock = 1;
1103 			vn_unlock(vp);
1104 		}
1105 
1106 		/*
1107 		 * WARNING!  If the device destroys itself the devfs node
1108 		 *	     can disappear here.
1109 		 *
1110 		 * WARNING!  vn_lock() will fail if the vp is in a VRECLAIM,
1111 		 *	     which can occur during umount.
1112 		 */
1113 		error = dev_dclose(dev, ap->a_fflag, S_IFCHR, ap->a_fp);
1114 		/* node is now stale */
1115 
1116 		if (needrelock) {
1117 			if (vn_lock(vp, LK_EXCLUSIVE |
1118 					LK_RETRY |
1119 					LK_FAILRECLAIM) != 0) {
1120 				panic("devfs_spec_close: vnode %p "
1121 				      "unexpectedly could not be relocked",
1122 				      vp);
1123 			}
1124 		}
1125 	} else {
1126 		error = 0;
1127 	}
1128 	devfs_debug(DEVFS_DEBUG_DEBUG, "devfs_spec_close() -2- \n");
1129 
1130 	/*
1131 	 * Track the actual opens and closes on the vnode.  The last close
1132 	 * disassociates the rdev.  If the rdev is already disassociated or
1133 	 * the opencount is already 0, the vnode might have been revoked
1134 	 * and no further opencount tracking occurs.
1135 	 */
1136 	if (dev)
1137 		release_dev(dev);
1138 	if (vp->v_opencount > 0)
1139 		vop_stdclose(ap);
1140 	return(error);
1141 
1142 }
1143 
1144 
1145 static int
1146 devfs_fo_close(struct file *fp)
1147 {
1148 	struct vnode *vp = (struct vnode *)fp->f_data;
1149 	int error;
1150 
1151 	fp->f_ops = &badfileops;
1152 	error = vn_close(vp, fp->f_flag, fp);
1153 	devfs_clear_cdevpriv(fp);
1154 
1155 	return (error);
1156 }
1157 
1158 
1159 /*
1160  * Device-optimized file table vnode read routine.
1161  *
1162  * This bypasses the VOP table and talks directly to the device.  Most
1163  * filesystems just route to specfs and can make this optimization.
1164  *
1165  * MPALMOSTSAFE - acquires mplock
1166  */
1167 static int
1168 devfs_fo_read(struct file *fp, struct uio *uio,
1169 		 struct ucred *cred, int flags)
1170 {
1171 	struct devfs_node *node;
1172 	struct vnode *vp;
1173 	int ioflag;
1174 	int error;
1175 	cdev_t dev;
1176 
1177 	KASSERT(uio->uio_td == curthread,
1178 		("uio_td %p is not td %p", uio->uio_td, curthread));
1179 
1180 	if (uio->uio_resid == 0)
1181 		return 0;
1182 
1183 	vp = (struct vnode *)fp->f_data;
1184 	if (vp == NULL || vp->v_type == VBAD)
1185 		return EBADF;
1186 
1187 	node = DEVFS_NODE(vp);
1188 
1189 	if ((dev = vp->v_rdev) == NULL)
1190 		return EBADF;
1191 
1192 	reference_dev(dev);
1193 
1194 	if ((flags & O_FOFFSET) == 0)
1195 		uio->uio_offset = fp->f_offset;
1196 
1197 	ioflag = 0;
1198 	if (flags & O_FBLOCKING) {
1199 		/* ioflag &= ~IO_NDELAY; */
1200 	} else if (flags & O_FNONBLOCKING) {
1201 		ioflag |= IO_NDELAY;
1202 	} else if (fp->f_flag & FNONBLOCK) {
1203 		ioflag |= IO_NDELAY;
1204 	}
1205 	if (flags & O_FBUFFERED) {
1206 		/* ioflag &= ~IO_DIRECT; */
1207 	} else if (flags & O_FUNBUFFERED) {
1208 		ioflag |= IO_DIRECT;
1209 	} else if (fp->f_flag & O_DIRECT) {
1210 		ioflag |= IO_DIRECT;
1211 	}
1212 	ioflag |= sequential_heuristic(uio, fp);
1213 
1214 	error = dev_dread(dev, uio, ioflag, fp);
1215 
1216 	release_dev(dev);
1217 	if (node)
1218 		nanotime(&node->atime);
1219 	if ((flags & O_FOFFSET) == 0)
1220 		fp->f_offset = uio->uio_offset;
1221 	fp->f_nextoff = uio->uio_offset;
1222 
1223 	return (error);
1224 }
1225 
1226 
1227 static int
1228 devfs_fo_write(struct file *fp, struct uio *uio,
1229 		  struct ucred *cred, int flags)
1230 {
1231 	struct devfs_node *node;
1232 	struct vnode *vp;
1233 	int ioflag;
1234 	int error;
1235 	cdev_t dev;
1236 
1237 	KASSERT(uio->uio_td == curthread,
1238 		("uio_td %p is not p %p", uio->uio_td, curthread));
1239 
1240 	vp = (struct vnode *)fp->f_data;
1241 	if (vp == NULL || vp->v_type == VBAD)
1242 		return EBADF;
1243 
1244 	node = DEVFS_NODE(vp);
1245 
1246 	if (vp->v_type == VREG)
1247 		bwillwrite(uio->uio_resid);
1248 
1249 	vp = (struct vnode *)fp->f_data;
1250 
1251 	if ((dev = vp->v_rdev) == NULL)
1252 		return EBADF;
1253 
1254 	reference_dev(dev);
1255 
1256 	if ((flags & O_FOFFSET) == 0)
1257 		uio->uio_offset = fp->f_offset;
1258 
1259 	ioflag = IO_UNIT;
1260 	if (vp->v_type == VREG &&
1261 	   ((fp->f_flag & O_APPEND) || (flags & O_FAPPEND))) {
1262 		ioflag |= IO_APPEND;
1263 	}
1264 
1265 	if (flags & O_FBLOCKING) {
1266 		/* ioflag &= ~IO_NDELAY; */
1267 	} else if (flags & O_FNONBLOCKING) {
1268 		ioflag |= IO_NDELAY;
1269 	} else if (fp->f_flag & FNONBLOCK) {
1270 		ioflag |= IO_NDELAY;
1271 	}
1272 	if (flags & O_FBUFFERED) {
1273 		/* ioflag &= ~IO_DIRECT; */
1274 	} else if (flags & O_FUNBUFFERED) {
1275 		ioflag |= IO_DIRECT;
1276 	} else if (fp->f_flag & O_DIRECT) {
1277 		ioflag |= IO_DIRECT;
1278 	}
1279 	if (flags & O_FASYNCWRITE) {
1280 		/* ioflag &= ~IO_SYNC; */
1281 	} else if (flags & O_FSYNCWRITE) {
1282 		ioflag |= IO_SYNC;
1283 	} else if (fp->f_flag & O_FSYNC) {
1284 		ioflag |= IO_SYNC;
1285 	}
1286 
1287 	if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))
1288 		ioflag |= IO_SYNC;
1289 	ioflag |= sequential_heuristic(uio, fp);
1290 
1291 	error = dev_dwrite(dev, uio, ioflag, fp);
1292 
1293 	release_dev(dev);
1294 	if (node) {
1295 		nanotime(&node->atime);
1296 		nanotime(&node->mtime);
1297 	}
1298 
1299 	if ((flags & O_FOFFSET) == 0)
1300 		fp->f_offset = uio->uio_offset;
1301 	fp->f_nextoff = uio->uio_offset;
1302 
1303 	return (error);
1304 }
1305 
1306 
1307 static int
1308 devfs_fo_stat(struct file *fp, struct stat *sb, struct ucred *cred)
1309 {
1310 	struct vnode *vp;
1311 	struct vattr vattr;
1312 	struct vattr *vap;
1313 	u_short mode;
1314 	cdev_t dev;
1315 	int error;
1316 
1317 	vp = (struct vnode *)fp->f_data;
1318 	if (vp == NULL || vp->v_type == VBAD)
1319 		return EBADF;
1320 
1321 	error = vn_stat(vp, sb, cred);
1322 	if (error)
1323 		return (error);
1324 
1325 	vap = &vattr;
1326 	error = VOP_GETATTR(vp, vap);
1327 	if (error)
1328 		return (error);
1329 
1330 	/*
1331 	 * Zero the spare stat fields
1332 	 */
1333 	sb->st_lspare = 0;
1334 	sb->st_qspare1 = 0;
1335 	sb->st_qspare2 = 0;
1336 
1337 	/*
1338 	 * Copy from vattr table ... or not in case it's a cloned device
1339 	 */
1340 	if (vap->va_fsid != VNOVAL)
1341 		sb->st_dev = vap->va_fsid;
1342 	else
1343 		sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0];
1344 
1345 	sb->st_ino = vap->va_fileid;
1346 
1347 	mode = vap->va_mode;
1348 	mode |= S_IFCHR;
1349 	sb->st_mode = mode;
1350 
1351 	if (vap->va_nlink > (nlink_t)-1)
1352 		sb->st_nlink = (nlink_t)-1;
1353 	else
1354 		sb->st_nlink = vap->va_nlink;
1355 
1356 	sb->st_uid = vap->va_uid;
1357 	sb->st_gid = vap->va_gid;
1358 	sb->st_rdev = dev2udev(DEVFS_NODE(vp)->d_dev);
1359 	sb->st_size = vap->va_bytes;
1360 	sb->st_atimespec = vap->va_atime;
1361 	sb->st_mtimespec = vap->va_mtime;
1362 	sb->st_ctimespec = vap->va_ctime;
1363 
1364 	/*
1365 	 * A VCHR and VBLK device may track the last access and last modified
1366 	 * time independantly of the filesystem.  This is particularly true
1367 	 * because device read and write calls may bypass the filesystem.
1368 	 */
1369 	if (vp->v_type == VCHR || vp->v_type == VBLK) {
1370 		dev = vp->v_rdev;
1371 		if (dev != NULL) {
1372 			if (dev->si_lastread) {
1373 				sb->st_atimespec.tv_sec = time_second +
1374 							  (time_uptime -
1375 							   dev->si_lastread);
1376 				sb->st_atimespec.tv_nsec = 0;
1377 			}
1378 			if (dev->si_lastwrite) {
1379 				sb->st_atimespec.tv_sec = time_second +
1380 							  (time_uptime -
1381 							   dev->si_lastwrite);
1382 				sb->st_atimespec.tv_nsec = 0;
1383 			}
1384 		}
1385 	}
1386 
1387         /*
1388 	 * According to www.opengroup.org, the meaning of st_blksize is
1389 	 *   "a filesystem-specific preferred I/O block size for this
1390 	 *    object.  In some filesystem types, this may vary from file
1391 	 *    to file"
1392 	 * Default to PAGE_SIZE after much discussion.
1393 	 */
1394 
1395 	sb->st_blksize = PAGE_SIZE;
1396 
1397 	sb->st_flags = vap->va_flags;
1398 
1399 	error = priv_check_cred(cred, PRIV_VFS_GENERATION, 0);
1400 	if (error)
1401 		sb->st_gen = 0;
1402 	else
1403 		sb->st_gen = (u_int32_t)vap->va_gen;
1404 
1405 	sb->st_blocks = vap->va_bytes / S_BLKSIZE;
1406 
1407 	return (0);
1408 }
1409 
1410 
1411 static int
1412 devfs_fo_kqfilter(struct file *fp, struct knote *kn)
1413 {
1414 	struct vnode *vp;
1415 	int error;
1416 	cdev_t dev;
1417 
1418 	vp = (struct vnode *)fp->f_data;
1419 	if (vp == NULL || vp->v_type == VBAD) {
1420 		error = EBADF;
1421 		goto done;
1422 	}
1423 	if ((dev = vp->v_rdev) == NULL) {
1424 		error = EBADF;
1425 		goto done;
1426 	}
1427 	reference_dev(dev);
1428 
1429 	error = dev_dkqfilter(dev, kn, fp);
1430 
1431 	release_dev(dev);
1432 
1433 done:
1434 	return (error);
1435 }
1436 
1437 /*
1438  * MPALMOSTSAFE - acquires mplock
1439  */
1440 static int
1441 devfs_fo_ioctl(struct file *fp, u_long com, caddr_t data,
1442 		  struct ucred *ucred, struct sysmsg *msg)
1443 {
1444 #if 0
1445 	struct devfs_node *node;
1446 #endif
1447 	struct vnode *vp;
1448 	struct vnode *ovp;
1449 	cdev_t	dev;
1450 	int error;
1451 	struct fiodname_args *name_args;
1452 	size_t namlen;
1453 	const char *name;
1454 
1455 	vp = ((struct vnode *)fp->f_data);
1456 
1457 	if ((dev = vp->v_rdev) == NULL)
1458 		return EBADF;		/* device was revoked */
1459 
1460 	reference_dev(dev);
1461 
1462 #if 0
1463 	node = DEVFS_NODE(vp);
1464 #endif
1465 
1466 	devfs_debug(DEVFS_DEBUG_DEBUG,
1467 		    "devfs_fo_ioctl() called! for dev %s\n",
1468 		    dev->si_name);
1469 
1470 	if (com == FIODTYPE) {
1471 		*(int *)data = dev_dflags(dev) & D_TYPEMASK;
1472 		error = 0;
1473 		goto out;
1474 	} else if (com == FIODNAME) {
1475 		name_args = (struct fiodname_args *)data;
1476 		name = dev->si_name;
1477 		namlen = strlen(name) + 1;
1478 
1479 		devfs_debug(DEVFS_DEBUG_DEBUG,
1480 			    "ioctl, got: FIODNAME for %s\n", name);
1481 
1482 		if (namlen <= name_args->len)
1483 			error = copyout(dev->si_name, name_args->name, namlen);
1484 		else
1485 			error = EINVAL;
1486 
1487 		devfs_debug(DEVFS_DEBUG_DEBUG,
1488 			    "ioctl stuff: error: %d\n", error);
1489 		goto out;
1490 	}
1491 
1492 	error = dev_dioctl(dev, com, data, fp->f_flag, ucred, msg, fp);
1493 
1494 #if 0
1495 	if (node) {
1496 		nanotime(&node->atime);
1497 		nanotime(&node->mtime);
1498 	}
1499 #endif
1500 	if (com == TIOCSCTTY) {
1501 		devfs_debug(DEVFS_DEBUG_DEBUG,
1502 			    "devfs_fo_ioctl: got TIOCSCTTY on %s\n",
1503 			    dev->si_name);
1504 	}
1505 	if (error == 0 && com == TIOCSCTTY) {
1506 		struct proc *p = curthread->td_proc;
1507 		struct session *sess;
1508 
1509 		devfs_debug(DEVFS_DEBUG_DEBUG,
1510 			    "devfs_fo_ioctl: dealing with TIOCSCTTY on %s\n",
1511 			    dev->si_name);
1512 		if (p == NULL) {
1513 			error = ENOTTY;
1514 			goto out;
1515 		}
1516 		sess = p->p_session;
1517 
1518 		/*
1519 		 * Do nothing if reassigning same control tty
1520 		 */
1521 		if (sess->s_ttyvp == vp) {
1522 			error = 0;
1523 			goto out;
1524 		}
1525 
1526 		/*
1527 		 * Get rid of reference to old control tty
1528 		 */
1529 		ovp = sess->s_ttyvp;
1530 		vref(vp);
1531 		sess->s_ttyvp = vp;
1532 		if (ovp)
1533 			vrele(ovp);
1534 	}
1535 
1536 out:
1537 	release_dev(dev);
1538 	devfs_debug(DEVFS_DEBUG_DEBUG, "devfs_fo_ioctl() finished! \n");
1539 	return (error);
1540 }
1541 
1542 
1543 static int
1544 devfs_spec_fsync(struct vop_fsync_args *ap)
1545 {
1546 	struct vnode *vp = ap->a_vp;
1547 	int error;
1548 
1549 	if (!vn_isdisk(vp, NULL))
1550 		return (0);
1551 
1552 	/*
1553 	 * Flush all dirty buffers associated with a block device.
1554 	 */
1555 	error = vfsync(vp, ap->a_waitfor, 10000, NULL, NULL);
1556 	return (error);
1557 }
1558 
1559 static int
1560 devfs_spec_read(struct vop_read_args *ap)
1561 {
1562 	struct devfs_node *node;
1563 	struct vnode *vp;
1564 	struct uio *uio;
1565 	cdev_t dev;
1566 	int error;
1567 
1568 	vp = ap->a_vp;
1569 	dev = vp->v_rdev;
1570 	uio = ap->a_uio;
1571 	node = DEVFS_NODE(vp);
1572 
1573 	if (dev == NULL)		/* device was revoked */
1574 		return (EBADF);
1575 	if (uio->uio_resid == 0)
1576 		return (0);
1577 
1578 	vn_unlock(vp);
1579 	error = dev_dread(dev, uio, ap->a_ioflag, NULL);
1580 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1581 
1582 	if (node)
1583 		nanotime(&node->atime);
1584 
1585 	return (error);
1586 }
1587 
1588 /*
1589  * Vnode op for write
1590  *
1591  * spec_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
1592  *	      struct ucred *a_cred)
1593  */
1594 static int
1595 devfs_spec_write(struct vop_write_args *ap)
1596 {
1597 	struct devfs_node *node;
1598 	struct vnode *vp;
1599 	struct uio *uio;
1600 	cdev_t dev;
1601 	int error;
1602 
1603 	vp = ap->a_vp;
1604 	dev = vp->v_rdev;
1605 	uio = ap->a_uio;
1606 	node = DEVFS_NODE(vp);
1607 
1608 	KKASSERT(uio->uio_segflg != UIO_NOCOPY);
1609 
1610 	if (dev == NULL)		/* device was revoked */
1611 		return (EBADF);
1612 
1613 	vn_unlock(vp);
1614 	error = dev_dwrite(dev, uio, ap->a_ioflag, NULL);
1615 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1616 
1617 	if (node) {
1618 		nanotime(&node->atime);
1619 		nanotime(&node->mtime);
1620 	}
1621 
1622 	return (error);
1623 }
1624 
1625 /*
1626  * Device ioctl operation.
1627  *
1628  * spec_ioctl(struct vnode *a_vp, int a_command, caddr_t a_data,
1629  *	      int a_fflag, struct ucred *a_cred, struct sysmsg *msg)
1630  */
1631 static int
1632 devfs_spec_ioctl(struct vop_ioctl_args *ap)
1633 {
1634 	struct vnode *vp = ap->a_vp;
1635 #if 0
1636 	struct devfs_node *node;
1637 #endif
1638 	cdev_t dev;
1639 
1640 	if ((dev = vp->v_rdev) == NULL)
1641 		return (EBADF);		/* device was revoked */
1642 #if 0
1643 	node = DEVFS_NODE(vp);
1644 
1645 	if (node) {
1646 		nanotime(&node->atime);
1647 		nanotime(&node->mtime);
1648 	}
1649 #endif
1650 
1651 	return (dev_dioctl(dev, ap->a_command, ap->a_data, ap->a_fflag,
1652 			   ap->a_cred, ap->a_sysmsg, NULL));
1653 }
1654 
1655 /*
1656  * spec_kqfilter(struct vnode *a_vp, struct knote *a_kn)
1657  */
1658 /* ARGSUSED */
1659 static int
1660 devfs_spec_kqfilter(struct vop_kqfilter_args *ap)
1661 {
1662 	struct vnode *vp = ap->a_vp;
1663 #if 0
1664 	struct devfs_node *node;
1665 #endif
1666 	cdev_t dev;
1667 
1668 	if ((dev = vp->v_rdev) == NULL)
1669 		return (EBADF);		/* device was revoked (EBADF) */
1670 #if 0
1671 	node = DEVFS_NODE(vp);
1672 
1673 	if (node)
1674 		nanotime(&node->atime);
1675 #endif
1676 
1677 	return (dev_dkqfilter(dev, ap->a_kn, NULL));
1678 }
1679 
1680 /*
1681  * Convert a vnode strategy call into a device strategy call.  Vnode strategy
1682  * calls are not limited to device DMA limits so we have to deal with the
1683  * case.
1684  *
1685  * spec_strategy(struct vnode *a_vp, struct bio *a_bio)
1686  */
1687 static int
1688 devfs_spec_strategy(struct vop_strategy_args *ap)
1689 {
1690 	struct bio *bio = ap->a_bio;
1691 	struct buf *bp = bio->bio_buf;
1692 	struct buf *nbp;
1693 	struct vnode *vp;
1694 	struct mount *mp;
1695 	int chunksize;
1696 	int maxiosize;
1697 
1698 	if (bp->b_cmd != BUF_CMD_READ && LIST_FIRST(&bp->b_dep) != NULL)
1699 		buf_start(bp);
1700 
1701 	/*
1702 	 * Collect statistics on synchronous and asynchronous read
1703 	 * and write counts for disks that have associated filesystems.
1704 	 */
1705 	vp = ap->a_vp;
1706 	KKASSERT(vp->v_rdev != NULL);	/* XXX */
1707 	if (vn_isdisk(vp, NULL) && (mp = vp->v_rdev->si_mountpoint) != NULL) {
1708 		if (bp->b_cmd == BUF_CMD_READ) {
1709 			if (bp->b_flags & BIO_SYNC)
1710 				mp->mnt_stat.f_syncreads++;
1711 			else
1712 				mp->mnt_stat.f_asyncreads++;
1713 		} else {
1714 			if (bp->b_flags & BIO_SYNC)
1715 				mp->mnt_stat.f_syncwrites++;
1716 			else
1717 				mp->mnt_stat.f_asyncwrites++;
1718 		}
1719 	}
1720 
1721         /*
1722          * Device iosize limitations only apply to read and write.  Shortcut
1723          * the I/O if it fits.
1724          */
1725 	if ((maxiosize = vp->v_rdev->si_iosize_max) == 0) {
1726 		devfs_debug(DEVFS_DEBUG_DEBUG,
1727 			    "%s: si_iosize_max not set!\n",
1728 			    dev_dname(vp->v_rdev));
1729 		maxiosize = MAXPHYS;
1730 	}
1731 #if SPEC_CHAIN_DEBUG & 2
1732 	maxiosize = 4096;
1733 #endif
1734         if (bp->b_bcount <= maxiosize ||
1735             (bp->b_cmd != BUF_CMD_READ && bp->b_cmd != BUF_CMD_WRITE)) {
1736                 dev_dstrategy_chain(vp->v_rdev, bio);
1737                 return (0);
1738         }
1739 
1740 	/*
1741 	 * Clone the buffer and set up an I/O chain to chunk up the I/O.
1742 	 */
1743 	nbp = kmalloc(sizeof(*bp), M_DEVBUF, M_INTWAIT|M_ZERO);
1744 	initbufbio(nbp);
1745 	buf_dep_init(nbp);
1746 	BUF_LOCK(nbp, LK_EXCLUSIVE);
1747 	BUF_KERNPROC(nbp);
1748 	nbp->b_vp = vp;
1749 	nbp->b_flags = B_PAGING | (bp->b_flags & B_BNOCLIP);
1750 	nbp->b_data = bp->b_data;
1751 	nbp->b_bio1.bio_done = devfs_spec_strategy_done;
1752 	nbp->b_bio1.bio_offset = bio->bio_offset;
1753 	nbp->b_bio1.bio_caller_info1.ptr = bio;
1754 
1755 	/*
1756 	 * Start the first transfer
1757 	 */
1758 	if (vn_isdisk(vp, NULL))
1759 		chunksize = vp->v_rdev->si_bsize_phys;
1760 	else
1761 		chunksize = DEV_BSIZE;
1762 	chunksize = maxiosize / chunksize * chunksize;
1763 #if SPEC_CHAIN_DEBUG & 1
1764 	devfs_debug(DEVFS_DEBUG_DEBUG,
1765 		    "spec_strategy chained I/O chunksize=%d\n",
1766 		    chunksize);
1767 #endif
1768 	nbp->b_cmd = bp->b_cmd;
1769 	nbp->b_bcount = chunksize;
1770 	nbp->b_bufsize = chunksize;	/* used to detect a short I/O */
1771 	nbp->b_bio1.bio_caller_info2.index = chunksize;
1772 
1773 #if SPEC_CHAIN_DEBUG & 1
1774 	devfs_debug(DEVFS_DEBUG_DEBUG,
1775 		    "spec_strategy: chain %p offset %d/%d bcount %d\n",
1776 		    bp, 0, bp->b_bcount, nbp->b_bcount);
1777 #endif
1778 
1779 	dev_dstrategy(vp->v_rdev, &nbp->b_bio1);
1780 
1781 	if (DEVFS_NODE(vp)) {
1782 		nanotime(&DEVFS_NODE(vp)->atime);
1783 		nanotime(&DEVFS_NODE(vp)->mtime);
1784 	}
1785 
1786 	return (0);
1787 }
1788 
1789 /*
1790  * Chunked up transfer completion routine - chain transfers until done
1791  *
1792  * NOTE: MPSAFE callback.
1793  */
1794 static
1795 void
1796 devfs_spec_strategy_done(struct bio *nbio)
1797 {
1798 	struct buf *nbp = nbio->bio_buf;
1799 	struct bio *bio = nbio->bio_caller_info1.ptr;	/* original bio */
1800 	struct buf *bp = bio->bio_buf;			/* original bp */
1801 	int chunksize = nbio->bio_caller_info2.index;	/* chunking */
1802 	int boffset = nbp->b_data - bp->b_data;
1803 
1804 	if (nbp->b_flags & B_ERROR) {
1805 		/*
1806 		 * An error terminates the chain, propogate the error back
1807 		 * to the original bp
1808 		 */
1809 		bp->b_flags |= B_ERROR;
1810 		bp->b_error = nbp->b_error;
1811 		bp->b_resid = bp->b_bcount - boffset +
1812 			      (nbp->b_bcount - nbp->b_resid);
1813 #if SPEC_CHAIN_DEBUG & 1
1814 		devfs_debug(DEVFS_DEBUG_DEBUG,
1815 			    "spec_strategy: chain %p error %d bcount %d/%d\n",
1816 			    bp, bp->b_error, bp->b_bcount,
1817 			    bp->b_bcount - bp->b_resid);
1818 #endif
1819 	} else if (nbp->b_resid) {
1820 		/*
1821 		 * A short read or write terminates the chain
1822 		 */
1823 		bp->b_error = nbp->b_error;
1824 		bp->b_resid = bp->b_bcount - boffset +
1825 			      (nbp->b_bcount - nbp->b_resid);
1826 #if SPEC_CHAIN_DEBUG & 1
1827 		devfs_debug(DEVFS_DEBUG_DEBUG,
1828 			    "spec_strategy: chain %p short read(1) "
1829 			    "bcount %d/%d\n",
1830 			    bp, bp->b_bcount - bp->b_resid, bp->b_bcount);
1831 #endif
1832 	} else if (nbp->b_bcount != nbp->b_bufsize) {
1833 		/*
1834 		 * A short read or write can also occur by truncating b_bcount
1835 		 */
1836 #if SPEC_CHAIN_DEBUG & 1
1837 		devfs_debug(DEVFS_DEBUG_DEBUG,
1838 			    "spec_strategy: chain %p short read(2) "
1839 			    "bcount %d/%d\n",
1840 			    bp, nbp->b_bcount + boffset, bp->b_bcount);
1841 #endif
1842 		bp->b_error = 0;
1843 		bp->b_bcount = nbp->b_bcount + boffset;
1844 		bp->b_resid = nbp->b_resid;
1845 	} else if (nbp->b_bcount + boffset == bp->b_bcount) {
1846 		/*
1847 		 * No more data terminates the chain
1848 		 */
1849 #if SPEC_CHAIN_DEBUG & 1
1850 		devfs_debug(DEVFS_DEBUG_DEBUG,
1851 			    "spec_strategy: chain %p finished bcount %d\n",
1852 			    bp, bp->b_bcount);
1853 #endif
1854 		bp->b_error = 0;
1855 		bp->b_resid = 0;
1856 	} else {
1857 		/*
1858 		 * Continue the chain
1859 		 */
1860 		boffset += nbp->b_bcount;
1861 		nbp->b_data = bp->b_data + boffset;
1862 		nbp->b_bcount = bp->b_bcount - boffset;
1863 		if (nbp->b_bcount > chunksize)
1864 			nbp->b_bcount = chunksize;
1865 		nbp->b_bio1.bio_done = devfs_spec_strategy_done;
1866 		nbp->b_bio1.bio_offset = bio->bio_offset + boffset;
1867 
1868 #if SPEC_CHAIN_DEBUG & 1
1869 		devfs_debug(DEVFS_DEBUG_DEBUG,
1870 			    "spec_strategy: chain %p offset %d/%d bcount %d\n",
1871 			    bp, boffset, bp->b_bcount, nbp->b_bcount);
1872 #endif
1873 
1874 		dev_dstrategy(nbp->b_vp->v_rdev, &nbp->b_bio1);
1875 		return;
1876 	}
1877 
1878 	/*
1879 	 * Fall through to here on termination.  biodone(bp) and
1880 	 * clean up and free nbp.
1881 	 */
1882 	biodone(bio);
1883 	BUF_UNLOCK(nbp);
1884 	uninitbufbio(nbp);
1885 	kfree(nbp, M_DEVBUF);
1886 }
1887 
1888 /*
1889  * spec_freeblks(struct vnode *a_vp, daddr_t a_addr, daddr_t a_length)
1890  */
1891 static int
1892 devfs_spec_freeblks(struct vop_freeblks_args *ap)
1893 {
1894 	struct buf *bp;
1895 
1896 	/*
1897 	 * XXX: This assumes that strategy does the deed right away.
1898 	 * XXX: this may not be TRTTD.
1899 	 */
1900 	KKASSERT(ap->a_vp->v_rdev != NULL);
1901 	if ((ap->a_vp->v_rdev->si_flags & SI_CANFREE) == 0)
1902 		return (0);
1903 	bp = geteblk(ap->a_length);
1904 	bp->b_cmd = BUF_CMD_FREEBLKS;
1905 	bp->b_bio1.bio_offset = ap->a_offset;
1906 	bp->b_bcount = ap->a_length;
1907 	dev_dstrategy(ap->a_vp->v_rdev, &bp->b_bio1);
1908 	return (0);
1909 }
1910 
1911 /*
1912  * Implement degenerate case where the block requested is the block
1913  * returned, and assume that the entire device is contiguous in regards
1914  * to the contiguous block range (runp and runb).
1915  *
1916  * spec_bmap(struct vnode *a_vp, off_t a_loffset,
1917  *	     off_t *a_doffsetp, int *a_runp, int *a_runb)
1918  */
1919 static int
1920 devfs_spec_bmap(struct vop_bmap_args *ap)
1921 {
1922 	if (ap->a_doffsetp != NULL)
1923 		*ap->a_doffsetp = ap->a_loffset;
1924 	if (ap->a_runp != NULL)
1925 		*ap->a_runp = MAXBSIZE;
1926 	if (ap->a_runb != NULL) {
1927 		if (ap->a_loffset < MAXBSIZE)
1928 			*ap->a_runb = (int)ap->a_loffset;
1929 		else
1930 			*ap->a_runb = MAXBSIZE;
1931 	}
1932 	return (0);
1933 }
1934 
1935 
1936 /*
1937  * Special device advisory byte-level locks.
1938  *
1939  * spec_advlock(struct vnode *a_vp, caddr_t a_id, int a_op,
1940  *		struct flock *a_fl, int a_flags)
1941  */
1942 /* ARGSUSED */
1943 static int
1944 devfs_spec_advlock(struct vop_advlock_args *ap)
1945 {
1946 	return ((ap->a_flags & F_POSIX) ? EINVAL : EOPNOTSUPP);
1947 }
1948 
1949 /*
1950  * NOTE: MPSAFE callback.
1951  */
1952 static void
1953 devfs_spec_getpages_iodone(struct bio *bio)
1954 {
1955 	bio->bio_buf->b_cmd = BUF_CMD_DONE;
1956 	wakeup(bio->bio_buf);
1957 }
1958 
1959 /*
1960  * spec_getpages() - get pages associated with device vnode.
1961  *
1962  * Note that spec_read and spec_write do not use the buffer cache, so we
1963  * must fully implement getpages here.
1964  */
1965 static int
1966 devfs_spec_getpages(struct vop_getpages_args *ap)
1967 {
1968 	vm_offset_t kva;
1969 	int error;
1970 	int i, pcount, size;
1971 	struct buf *bp;
1972 	vm_page_t m;
1973 	vm_ooffset_t offset;
1974 	int toff, nextoff, nread;
1975 	struct vnode *vp = ap->a_vp;
1976 	int blksiz;
1977 	int gotreqpage;
1978 
1979 	error = 0;
1980 	pcount = round_page(ap->a_count) / PAGE_SIZE;
1981 
1982 	/*
1983 	 * Calculate the offset of the transfer and do sanity check.
1984 	 */
1985 	offset = IDX_TO_OFF(ap->a_m[0]->pindex) + ap->a_offset;
1986 
1987 	/*
1988 	 * Round up physical size for real devices.  We cannot round using
1989 	 * v_mount's block size data because v_mount has nothing to do with
1990 	 * the device.  i.e. it's usually '/dev'.  We need the physical block
1991 	 * size for the device itself.
1992 	 *
1993 	 * We can't use v_rdev->si_mountpoint because it only exists when the
1994 	 * block device is mounted.  However, we can use v_rdev.
1995 	 */
1996 	if (vn_isdisk(vp, NULL))
1997 		blksiz = vp->v_rdev->si_bsize_phys;
1998 	else
1999 		blksiz = DEV_BSIZE;
2000 
2001 	size = (ap->a_count + blksiz - 1) & ~(blksiz - 1);
2002 
2003 	bp = getpbuf_kva(NULL);
2004 	kva = (vm_offset_t)bp->b_data;
2005 
2006 	/*
2007 	 * Map the pages to be read into the kva.
2008 	 */
2009 	pmap_qenter(kva, ap->a_m, pcount);
2010 
2011 	/* Build a minimal buffer header. */
2012 	bp->b_cmd = BUF_CMD_READ;
2013 	bp->b_bcount = size;
2014 	bp->b_resid = 0;
2015 	bsetrunningbufspace(bp, size);
2016 
2017 	bp->b_bio1.bio_offset = offset;
2018 	bp->b_bio1.bio_done = devfs_spec_getpages_iodone;
2019 
2020 	mycpu->gd_cnt.v_vnodein++;
2021 	mycpu->gd_cnt.v_vnodepgsin += pcount;
2022 
2023 	/* Do the input. */
2024 	vn_strategy(ap->a_vp, &bp->b_bio1);
2025 
2026 	crit_enter();
2027 
2028 	/* We definitely need to be at splbio here. */
2029 	while (bp->b_cmd != BUF_CMD_DONE)
2030 		tsleep(bp, 0, "spread", 0);
2031 
2032 	crit_exit();
2033 
2034 	if (bp->b_flags & B_ERROR) {
2035 		if (bp->b_error)
2036 			error = bp->b_error;
2037 		else
2038 			error = EIO;
2039 	}
2040 
2041 	/*
2042 	 * If EOF is encountered we must zero-extend the result in order
2043 	 * to ensure that the page does not contain garabge.  When no
2044 	 * error occurs, an early EOF is indicated if b_bcount got truncated.
2045 	 * b_resid is relative to b_bcount and should be 0, but some devices
2046 	 * might indicate an EOF with b_resid instead of truncating b_bcount.
2047 	 */
2048 	nread = bp->b_bcount - bp->b_resid;
2049 	if (nread < ap->a_count)
2050 		bzero((caddr_t)kva + nread, ap->a_count - nread);
2051 	pmap_qremove(kva, pcount);
2052 
2053 	gotreqpage = 0;
2054 	for (i = 0, toff = 0; i < pcount; i++, toff = nextoff) {
2055 		nextoff = toff + PAGE_SIZE;
2056 		m = ap->a_m[i];
2057 
2058 		m->flags &= ~PG_ZERO;
2059 
2060 		/*
2061 		 * NOTE: vm_page_undirty/clear_dirty etc do not clear the
2062 		 *	 pmap modified bit.  pmap modified bit should have
2063 		 *	 already been cleared.
2064 		 */
2065 		if (nextoff <= nread) {
2066 			m->valid = VM_PAGE_BITS_ALL;
2067 			vm_page_undirty(m);
2068 		} else if (toff < nread) {
2069 			/*
2070 			 * Since this is a VM request, we have to supply the
2071 			 * unaligned offset to allow vm_page_set_valid()
2072 			 * to zero sub-DEV_BSIZE'd portions of the page.
2073 			 */
2074 			vm_page_set_valid(m, 0, nread - toff);
2075 			vm_page_clear_dirty_end_nonincl(m, 0, nread - toff);
2076 		} else {
2077 			m->valid = 0;
2078 			vm_page_undirty(m);
2079 		}
2080 
2081 		if (i != ap->a_reqpage) {
2082 			/*
2083 			 * Just in case someone was asking for this page we
2084 			 * now tell them that it is ok to use.
2085 			 */
2086 			if (!error || (m->valid == VM_PAGE_BITS_ALL)) {
2087 				if (m->valid) {
2088 					if (m->flags & PG_REFERENCED) {
2089 						vm_page_activate(m);
2090 					} else {
2091 						vm_page_deactivate(m);
2092 					}
2093 					vm_page_wakeup(m);
2094 				} else {
2095 					vm_page_free(m);
2096 				}
2097 			} else {
2098 				vm_page_free(m);
2099 			}
2100 		} else if (m->valid) {
2101 			gotreqpage = 1;
2102 			/*
2103 			 * Since this is a VM request, we need to make the
2104 			 * entire page presentable by zeroing invalid sections.
2105 			 */
2106 			if (m->valid != VM_PAGE_BITS_ALL)
2107 			    vm_page_zero_invalid(m, FALSE);
2108 		}
2109 	}
2110 	if (!gotreqpage) {
2111 		m = ap->a_m[ap->a_reqpage];
2112 		devfs_debug(DEVFS_DEBUG_WARNING,
2113 	    "spec_getpages:(%s) I/O read failure: (error=%d) bp %p vp %p\n",
2114 			devtoname(vp->v_rdev), error, bp, bp->b_vp);
2115 		devfs_debug(DEVFS_DEBUG_WARNING,
2116 	    "               size: %d, resid: %d, a_count: %d, valid: 0x%x\n",
2117 		    size, bp->b_resid, ap->a_count, m->valid);
2118 		devfs_debug(DEVFS_DEBUG_WARNING,
2119 	    "               nread: %d, reqpage: %d, pindex: %lu, pcount: %d\n",
2120 		    nread, ap->a_reqpage, (u_long)m->pindex, pcount);
2121 		/*
2122 		 * Free the buffer header back to the swap buffer pool.
2123 		 */
2124 		relpbuf(bp, NULL);
2125 		return VM_PAGER_ERROR;
2126 	}
2127 	/*
2128 	 * Free the buffer header back to the swap buffer pool.
2129 	 */
2130 	relpbuf(bp, NULL);
2131 	if (DEVFS_NODE(ap->a_vp))
2132 		nanotime(&DEVFS_NODE(ap->a_vp)->mtime);
2133 	return VM_PAGER_OK;
2134 }
2135 
2136 static __inline
2137 int
2138 sequential_heuristic(struct uio *uio, struct file *fp)
2139 {
2140 	/*
2141 	 * Sequential heuristic - detect sequential operation
2142 	 */
2143 	if ((uio->uio_offset == 0 && fp->f_seqcount > 0) ||
2144 	    uio->uio_offset == fp->f_nextoff) {
2145 		/*
2146 		 * XXX we assume that the filesystem block size is
2147 		 * the default.  Not true, but still gives us a pretty
2148 		 * good indicator of how sequential the read operations
2149 		 * are.
2150 		 */
2151 		int tmpseq = fp->f_seqcount;
2152 
2153 		tmpseq += (uio->uio_resid + BKVASIZE - 1) / BKVASIZE;
2154 		if (tmpseq > IO_SEQMAX)
2155 			tmpseq = IO_SEQMAX;
2156 		fp->f_seqcount = tmpseq;
2157 		return(fp->f_seqcount << IO_SEQSHIFT);
2158 	}
2159 
2160 	/*
2161 	 * Not sequential, quick draw-down of seqcount
2162 	 */
2163 	if (fp->f_seqcount > 1)
2164 		fp->f_seqcount = 1;
2165 	else
2166 		fp->f_seqcount = 0;
2167 	return(0);
2168 }
2169