xref: /dragonfly/sys/vfs/devfs/devfs_vnops.c (revision 0dace59e)
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 	if ((error = vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY)) != 0)
330 		return (error);
331 
332 	if (!devfs_node_is_accessible(dnode)) {
333 		vn_unlock(ap->a_vp);
334 		return ENOENT;
335 	}
336 
337 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
338 
339 	saveoff = ap->a_uio->uio_offset;
340 
341 	if (ap->a_ncookies) {
342 		ncookies = ap->a_uio->uio_resid / 16 + 1; /* Why / 16 ?? */
343 		if (ncookies > 256)
344 			ncookies = 256;
345 		cookies = kmalloc(256 * sizeof(off_t), M_TEMP, M_WAITOK);
346 		cookie_index = 0;
347 	} else {
348 		ncookies = -1;
349 		cookies = NULL;
350 		cookie_index = 0;
351 	}
352 
353 	nanotime(&dnode->atime);
354 
355 	if (saveoff == 0) {
356 		r = vop_write_dirent(&error, ap->a_uio, dnode->d_dir.d_ino,
357 				     DT_DIR, 1, ".");
358 		if (r)
359 			goto done;
360 		if (cookies)
361 			cookies[cookie_index] = saveoff;
362 		saveoff++;
363 		cookie_index++;
364 		if (cookie_index == ncookies)
365 			goto done;
366 	}
367 
368 	if (saveoff == 1) {
369 		if (dnode->parent) {
370 			r = vop_write_dirent(&error, ap->a_uio,
371 					     dnode->parent->d_dir.d_ino,
372 					     DT_DIR, 2, "..");
373 		} else {
374 			r = vop_write_dirent(&error, ap->a_uio,
375 					     dnode->d_dir.d_ino,
376 					     DT_DIR, 2, "..");
377 		}
378 		if (r)
379 			goto done;
380 		if (cookies)
381 			cookies[cookie_index] = saveoff;
382 		saveoff++;
383 		cookie_index++;
384 		if (cookie_index == ncookies)
385 			goto done;
386 	}
387 
388 	TAILQ_FOREACH(node, DEVFS_DENODE_HEAD(dnode), link) {
389 		if ((node->flags & DEVFS_HIDDEN) ||
390 		    (node->flags & DEVFS_INVISIBLE)) {
391 			continue;
392 		}
393 
394 		/*
395 		 * If the node type is a valid devfs alias, then we make
396 		 * sure that the target isn't hidden. If it is, we don't
397 		 * show the link in the directory listing.
398 		 */
399 		if ((node->node_type == Nlink) && (node->link_target != NULL) &&
400 			(node->link_target->flags & DEVFS_HIDDEN))
401 			continue;
402 
403 		if (node->cookie < saveoff)
404 			continue;
405 
406 		saveoff = node->cookie;
407 
408 		error2 = vop_write_dirent(&error, ap->a_uio, node->d_dir.d_ino,
409 					  node->d_dir.d_type,
410 					  node->d_dir.d_namlen,
411 					  node->d_dir.d_name);
412 
413 		if (error2)
414 			break;
415 
416 		saveoff++;
417 
418 		if (cookies)
419 			cookies[cookie_index] = node->cookie;
420 		++cookie_index;
421 		if (cookie_index == ncookies)
422 			break;
423 	}
424 
425 done:
426 	lockmgr(&devfs_lock, LK_RELEASE);
427 	vn_unlock(ap->a_vp);
428 
429 	ap->a_uio->uio_offset = saveoff;
430 	if (error && cookie_index == 0) {
431 		if (cookies) {
432 			kfree(cookies, M_TEMP);
433 			*ap->a_ncookies = 0;
434 			*ap->a_cookies = NULL;
435 		}
436 	} else {
437 		if (cookies) {
438 			*ap->a_ncookies = cookie_index;
439 			*ap->a_cookies = cookies;
440 		}
441 	}
442 	return (error);
443 }
444 
445 
446 static int
447 devfs_vop_nresolve(struct vop_nresolve_args *ap)
448 {
449 	struct devfs_node *dnode = DEVFS_NODE(ap->a_dvp);
450 	struct devfs_node *node, *found = NULL;
451 	struct namecache *ncp;
452 	struct vnode *vp = NULL;
453 	int error = 0;
454 	int len;
455 	int depth;
456 
457 	ncp = ap->a_nch->ncp;
458 	len = ncp->nc_nlen;
459 
460 	if (!devfs_node_is_accessible(dnode))
461 		return ENOENT;
462 
463 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
464 
465 	if ((dnode->node_type != Nroot) && (dnode->node_type != Ndir)) {
466 		error = ENOENT;
467 		cache_setvp(ap->a_nch, NULL);
468 		goto out;
469 	}
470 
471 	TAILQ_FOREACH(node, DEVFS_DENODE_HEAD(dnode), link) {
472 		if (len == node->d_dir.d_namlen) {
473 			if (!memcmp(ncp->nc_name, node->d_dir.d_name, len)) {
474 				found = node;
475 				break;
476 			}
477 		}
478 	}
479 
480 	if (found) {
481 		depth = 0;
482 		while ((found->node_type == Nlink) && (found->link_target)) {
483 			if (depth >= 8) {
484 				devfs_debug(DEVFS_DEBUG_SHOW, "Recursive link or depth >= 8");
485 				break;
486 			}
487 
488 			found = found->link_target;
489 			++depth;
490 		}
491 
492 		if (!(found->flags & DEVFS_HIDDEN))
493 			devfs_allocv(/*ap->a_dvp->v_mount, */ &vp, found);
494 	}
495 
496 	if (vp == NULL) {
497 		error = ENOENT;
498 		cache_setvp(ap->a_nch, NULL);
499 		goto out;
500 
501 	}
502 	KKASSERT(vp);
503 	vn_unlock(vp);
504 	cache_setvp(ap->a_nch, vp);
505 	vrele(vp);
506 out:
507 	lockmgr(&devfs_lock, LK_RELEASE);
508 
509 	return error;
510 }
511 
512 
513 static int
514 devfs_vop_nlookupdotdot(struct vop_nlookupdotdot_args *ap)
515 {
516 	struct devfs_node *dnode = DEVFS_NODE(ap->a_dvp);
517 
518 	*ap->a_vpp = NULL;
519 	if (!devfs_node_is_accessible(dnode))
520 		return ENOENT;
521 
522 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
523 	if (dnode->parent != NULL) {
524 		devfs_allocv(ap->a_vpp, dnode->parent);
525 		vn_unlock(*ap->a_vpp);
526 	}
527 	lockmgr(&devfs_lock, LK_RELEASE);
528 
529 	return ((*ap->a_vpp == NULL) ? ENOENT : 0);
530 }
531 
532 
533 static int
534 devfs_vop_getattr(struct vop_getattr_args *ap)
535 {
536 	struct devfs_node *node = DEVFS_NODE(ap->a_vp);
537 	struct vattr *vap = ap->a_vap;
538 	struct partinfo pinfo;
539 	int error = 0;
540 
541 #if 0
542 	if (!devfs_node_is_accessible(node))
543 		return ENOENT;
544 #endif
545 	node_sync_dev_get(node);
546 
547 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
548 
549 	/* start by zeroing out the attributes */
550 	VATTR_NULL(vap);
551 
552 	/* next do all the common fields */
553 	vap->va_type = ap->a_vp->v_type;
554 	vap->va_mode = node->mode;
555 	vap->va_fileid = DEVFS_NODE(ap->a_vp)->d_dir.d_ino ;
556 	vap->va_flags = 0;
557 	vap->va_blocksize = DEV_BSIZE;
558 	vap->va_bytes = vap->va_size = 0;
559 
560 	vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
561 
562 	vap->va_atime = node->atime;
563 	vap->va_mtime = node->mtime;
564 	vap->va_ctime = node->ctime;
565 
566 	vap->va_nlink = 1; /* number of references to file */
567 
568 	vap->va_uid = node->uid;
569 	vap->va_gid = node->gid;
570 
571 	vap->va_rmajor = 0;
572 	vap->va_rminor = 0;
573 
574 	if ((node->node_type == Ndev) && node->d_dev)  {
575 		reference_dev(node->d_dev);
576 		vap->va_rminor = node->d_dev->si_uminor;
577 		release_dev(node->d_dev);
578 	}
579 
580 	/* For a softlink the va_size is the length of the softlink */
581 	if (node->symlink_name != 0) {
582 		vap->va_bytes = vap->va_size = node->symlink_namelen;
583 	}
584 
585 	/*
586 	 * For a disk-type device, va_size is the size of the underlying
587 	 * device, so that lseek() works properly.
588 	 */
589 	if ((node->d_dev) && (dev_dflags(node->d_dev) & D_DISK)) {
590 		bzero(&pinfo, sizeof(pinfo));
591 		error = dev_dioctl(node->d_dev, DIOCGPART, (void *)&pinfo,
592 				   0, proc0.p_ucred, NULL);
593 		if ((error == 0) && (pinfo.media_blksize != 0)) {
594 			vap->va_size = pinfo.media_size;
595 		} else {
596 			vap->va_size = 0;
597 			error = 0;
598 		}
599 	}
600 
601 	lockmgr(&devfs_lock, LK_RELEASE);
602 
603 	return (error);
604 }
605 
606 
607 static int
608 devfs_vop_setattr(struct vop_setattr_args *ap)
609 {
610 	struct devfs_node *node = DEVFS_NODE(ap->a_vp);
611 	struct vattr *vap;
612 	uid_t cur_uid;
613 	gid_t cur_gid;
614 	mode_t cur_mode;
615 	int error = 0;
616 
617 	if (!devfs_node_is_accessible(node))
618 		return ENOENT;
619 	node_sync_dev_get(node);
620 
621 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
622 
623 	vap = ap->a_vap;
624 
625 	if ((vap->va_uid != (uid_t)VNOVAL) || (vap->va_gid != (gid_t)VNOVAL)) {
626 		cur_uid = node->uid;
627 		cur_gid = node->gid;
628 		cur_mode = node->mode;
629 		error = vop_helper_chown(ap->a_vp, vap->va_uid, vap->va_gid,
630 		    ap->a_cred, &cur_uid, &cur_gid, &cur_mode);
631 		if (error)
632 			goto out;
633 
634 		if (node->uid != cur_uid || node->gid != cur_gid) {
635 			node->uid = cur_uid;
636 			node->gid = cur_gid;
637 			node->mode = cur_mode;
638 		}
639 	}
640 
641 	if (vap->va_mode != (mode_t)VNOVAL) {
642 		cur_mode = node->mode;
643 		error = vop_helper_chmod(ap->a_vp, vap->va_mode, ap->a_cred,
644 		    node->uid, node->gid, &cur_mode);
645 		if (error == 0 && node->mode != cur_mode) {
646 			node->mode = cur_mode;
647 		}
648 	}
649 
650 out:
651 	node_sync_dev_set(node);
652 	nanotime(&node->ctime);
653 	lockmgr(&devfs_lock, LK_RELEASE);
654 
655 	return error;
656 }
657 
658 
659 static int
660 devfs_vop_readlink(struct vop_readlink_args *ap)
661 {
662 	struct devfs_node *node = DEVFS_NODE(ap->a_vp);
663 	int ret;
664 
665 	if (!devfs_node_is_accessible(node))
666 		return ENOENT;
667 
668 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
669 	ret = uiomove(node->symlink_name, node->symlink_namelen, ap->a_uio);
670 	lockmgr(&devfs_lock, LK_RELEASE);
671 
672 	return ret;
673 }
674 
675 
676 static int
677 devfs_vop_print(struct vop_print_args *ap)
678 {
679 	return (0);
680 }
681 
682 static int
683 devfs_vop_nmkdir(struct vop_nmkdir_args *ap)
684 {
685 	struct devfs_node *dnode = DEVFS_NODE(ap->a_dvp);
686 	struct devfs_node *node;
687 
688 	if (!devfs_node_is_accessible(dnode))
689 		return ENOENT;
690 
691 	if ((dnode->node_type != Nroot) && (dnode->node_type != Ndir))
692 		goto out;
693 
694 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
695 	devfs_allocvp(ap->a_dvp->v_mount, ap->a_vpp, Ndir,
696 		      ap->a_nch->ncp->nc_name, dnode, NULL);
697 
698 	if (*ap->a_vpp) {
699 		node = DEVFS_NODE(*ap->a_vpp);
700 		node->flags |= DEVFS_USER_CREATED;
701 		cache_setunresolved(ap->a_nch);
702 		cache_setvp(ap->a_nch, *ap->a_vpp);
703 	}
704 	lockmgr(&devfs_lock, LK_RELEASE);
705 out:
706 	return ((*ap->a_vpp == NULL) ? ENOTDIR : 0);
707 }
708 
709 static int
710 devfs_vop_nsymlink(struct vop_nsymlink_args *ap)
711 {
712 	struct devfs_node *dnode = DEVFS_NODE(ap->a_dvp);
713 	struct devfs_node *node;
714 	size_t targetlen;
715 
716 	if (!devfs_node_is_accessible(dnode))
717 		return ENOENT;
718 
719 	ap->a_vap->va_type = VLNK;
720 
721 	if ((dnode->node_type != Nroot) && (dnode->node_type != Ndir))
722 		goto out;
723 
724 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
725 	devfs_allocvp(ap->a_dvp->v_mount, ap->a_vpp, Nlink,
726 		      ap->a_nch->ncp->nc_name, dnode, NULL);
727 
728 	targetlen = strlen(ap->a_target);
729 	if (*ap->a_vpp) {
730 		node = DEVFS_NODE(*ap->a_vpp);
731 		node->flags |= DEVFS_USER_CREATED;
732 		node->symlink_namelen = targetlen;
733 		node->symlink_name = kmalloc(targetlen + 1, M_DEVFS, M_WAITOK);
734 		memcpy(node->symlink_name, ap->a_target, targetlen);
735 		node->symlink_name[targetlen] = '\0';
736 		cache_setunresolved(ap->a_nch);
737 		cache_setvp(ap->a_nch, *ap->a_vpp);
738 	}
739 	lockmgr(&devfs_lock, LK_RELEASE);
740 out:
741 	return ((*ap->a_vpp == NULL) ? ENOTDIR : 0);
742 }
743 
744 static int
745 devfs_vop_nrmdir(struct vop_nrmdir_args *ap)
746 {
747 	struct devfs_node *dnode = DEVFS_NODE(ap->a_dvp);
748 	struct devfs_node *node;
749 	struct namecache *ncp;
750 	int error = ENOENT;
751 
752 	ncp = ap->a_nch->ncp;
753 
754 	if (!devfs_node_is_accessible(dnode))
755 		return ENOENT;
756 
757 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
758 
759 	if ((dnode->node_type != Nroot) && (dnode->node_type != Ndir))
760 		goto out;
761 
762 	TAILQ_FOREACH(node, DEVFS_DENODE_HEAD(dnode), link) {
763 		if (ncp->nc_nlen != node->d_dir.d_namlen)
764 			continue;
765 		if (memcmp(ncp->nc_name, node->d_dir.d_name, ncp->nc_nlen))
766 			continue;
767 
768 		/*
769 		 * only allow removal of user created dirs
770 		 */
771 		if ((node->flags & DEVFS_USER_CREATED) == 0) {
772 			error = EPERM;
773 			goto out;
774 		} else if (node->node_type != Ndir) {
775 			error = ENOTDIR;
776 			goto out;
777 		} else if (node->nchildren > 2) {
778 			error = ENOTEMPTY;
779 			goto out;
780 		} else {
781 			if (node->v_node)
782 				cache_inval_vp(node->v_node, CINV_DESTROY);
783 			devfs_unlinkp(node);
784 			error = 0;
785 			break;
786 		}
787 	}
788 
789 	cache_unlink(ap->a_nch);
790 out:
791 	lockmgr(&devfs_lock, LK_RELEASE);
792 	return error;
793 }
794 
795 static int
796 devfs_vop_nremove(struct vop_nremove_args *ap)
797 {
798 	struct devfs_node *dnode = DEVFS_NODE(ap->a_dvp);
799 	struct devfs_node *node;
800 	struct namecache *ncp;
801 	int error = ENOENT;
802 
803 	ncp = ap->a_nch->ncp;
804 
805 	if (!devfs_node_is_accessible(dnode))
806 		return ENOENT;
807 
808 	lockmgr(&devfs_lock, LK_EXCLUSIVE);
809 
810 	if ((dnode->node_type != Nroot) && (dnode->node_type != Ndir))
811 		goto out;
812 
813 	TAILQ_FOREACH(node, DEVFS_DENODE_HEAD(dnode), link) {
814 		if (ncp->nc_nlen != node->d_dir.d_namlen)
815 			continue;
816 		if (memcmp(ncp->nc_name, node->d_dir.d_name, ncp->nc_nlen))
817 			continue;
818 
819 		/*
820 		 * only allow removal of user created stuff (e.g. symlinks)
821 		 */
822 		if ((node->flags & DEVFS_USER_CREATED) == 0) {
823 			error = EPERM;
824 			goto out;
825 		} else if (node->node_type == Ndir) {
826 			error = EISDIR;
827 			goto out;
828 		} else {
829 			if (node->v_node)
830 				cache_inval_vp(node->v_node, CINV_DESTROY);
831 			devfs_unlinkp(node);
832 			error = 0;
833 			break;
834 		}
835 	}
836 
837 	cache_unlink(ap->a_nch);
838 out:
839 	lockmgr(&devfs_lock, LK_RELEASE);
840 	return error;
841 }
842 
843 
844 static int
845 devfs_spec_open(struct vop_open_args *ap)
846 {
847 	struct vnode *vp = ap->a_vp;
848 	struct vnode *orig_vp = NULL;
849 	struct devfs_node *node = DEVFS_NODE(vp);
850 	struct devfs_node *newnode;
851 	cdev_t dev, ndev = NULL;
852 	int error = 0;
853 
854 	if (node) {
855 		if (node->d_dev == NULL)
856 			return ENXIO;
857 		if (!devfs_node_is_accessible(node))
858 			return ENOENT;
859 	}
860 
861 	if ((dev = vp->v_rdev) == NULL)
862 		return ENXIO;
863 
864 	if (node && ap->a_fp) {
865 		devfs_debug(DEVFS_DEBUG_DEBUG, "devfs_spec_open: -1.1-\n");
866 		lockmgr(&devfs_lock, LK_EXCLUSIVE);
867 
868 		ndev = devfs_clone(dev, node->d_dir.d_name, node->d_dir.d_namlen,
869 						ap->a_mode, ap->a_cred);
870 		if (ndev != NULL) {
871 			newnode = devfs_create_device_node(
872 					DEVFS_MNTDATA(vp->v_mount)->root_node,
873 					ndev, NULL, NULL);
874 			/* XXX: possibly destroy device if this happens */
875 
876 			if (newnode != NULL) {
877 				dev = ndev;
878 				devfs_link_dev(dev);
879 
880 				devfs_debug(DEVFS_DEBUG_DEBUG,
881 						"parent here is: %s, node is: |%s|\n",
882 						((node->parent->node_type == Nroot) ?
883 						"ROOT!" : node->parent->d_dir.d_name),
884 						newnode->d_dir.d_name);
885 				devfs_debug(DEVFS_DEBUG_DEBUG,
886 						"test: %s\n",
887 						((struct devfs_node *)(TAILQ_LAST(DEVFS_DENODE_HEAD(node->parent), devfs_node_head)))->d_dir.d_name);
888 
889 				/*
890 				 * orig_vp is set to the original vp if we cloned.
891 				 */
892 				/* node->flags |= DEVFS_CLONED; */
893 				devfs_allocv(&vp, newnode);
894 				orig_vp = ap->a_vp;
895 				ap->a_vp = vp;
896 			}
897 		}
898 		lockmgr(&devfs_lock, LK_RELEASE);
899 	}
900 
901 	devfs_debug(DEVFS_DEBUG_DEBUG,
902 		    "devfs_spec_open() called on %s! \n",
903 		    dev->si_name);
904 
905 	/*
906 	 * Make this field valid before any I/O in ->d_open
907 	 */
908 	if (!dev->si_iosize_max)
909 		/* XXX: old DFLTPHYS == 64KB dependency */
910 		dev->si_iosize_max = min(MAXPHYS,64*1024);
911 
912 	if (dev_dflags(dev) & D_TTY)
913 		vsetflags(vp, VISTTY);
914 
915 	/*
916 	 * Open underlying device
917 	 */
918 	vn_unlock(vp);
919 	error = dev_dopen(dev, ap->a_mode, S_IFCHR, ap->a_cred);
920 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
921 
922 	/*
923 	 * Clean up any cloned vp if we error out.
924 	 */
925 	if (error) {
926 		if (orig_vp) {
927 			vput(vp);
928 			ap->a_vp = orig_vp;
929 			/* orig_vp = NULL; */
930 		}
931 		return error;
932 	}
933 
934 	/*
935 	 * This checks if the disk device is going to be opened for writing.
936 	 * It will be only allowed in the cases where securelevel permits it
937 	 * and it's not mounted R/W.
938 	 */
939 	if ((dev_dflags(dev) & D_DISK) && (ap->a_mode & FWRITE) &&
940 	    (ap->a_cred != FSCRED)) {
941 
942 		/* Very secure mode. No open for writing allowed */
943 		if (securelevel >= 2)
944 			return EPERM;
945 
946 		/*
947 		 * If it is mounted R/W, do not allow to open for writing.
948 		 * In the case it's mounted read-only but securelevel
949 		 * is >= 1, then do not allow opening for writing either.
950 		 */
951 		if (vfs_mountedon(vp)) {
952 			if (!(dev->si_mountpoint->mnt_flag & MNT_RDONLY))
953 				return EBUSY;
954 			else if (securelevel >= 1)
955 				return EPERM;
956 		}
957 	}
958 
959 	if (dev_dflags(dev) & D_TTY) {
960 		if (dev->si_tty) {
961 			struct tty *tp;
962 			tp = dev->si_tty;
963 			if (!tp->t_stop) {
964 				devfs_debug(DEVFS_DEBUG_DEBUG,
965 					    "devfs: no t_stop\n");
966 				tp->t_stop = nottystop;
967 			}
968 		}
969 	}
970 
971 
972 	if (vn_isdisk(vp, NULL)) {
973 		if (!dev->si_bsize_phys)
974 			dev->si_bsize_phys = DEV_BSIZE;
975 		vinitvmio(vp, IDX_TO_OFF(INT_MAX), PAGE_SIZE, -1);
976 	}
977 
978 	vop_stdopen(ap);
979 #if 0
980 	if (node)
981 		nanotime(&node->atime);
982 #endif
983 
984 	/*
985 	 * If we replaced the vp the vop_stdopen() call will have loaded
986 	 * it into fp->f_data and vref()d the vp, giving us two refs.  So
987 	 * instead of just unlocking it here we have to vput() it.
988 	 */
989 	if (orig_vp)
990 		vput(vp);
991 
992 	/* Ugly pty magic, to make pty devices appear once they are opened */
993 	if (node && (node->flags & DEVFS_PTY) == DEVFS_PTY)
994 		node->flags &= ~DEVFS_INVISIBLE;
995 
996 	if (ap->a_fp) {
997 		KKASSERT(ap->a_fp->f_type == DTYPE_VNODE);
998 		KKASSERT((ap->a_fp->f_flag & FMASK) == (ap->a_mode & FMASK));
999 		ap->a_fp->f_ops = &devfs_dev_fileops;
1000 		KKASSERT(ap->a_fp->f_data == (void *)vp);
1001 	}
1002 
1003 	return 0;
1004 }
1005 
1006 
1007 static int
1008 devfs_spec_close(struct vop_close_args *ap)
1009 {
1010 	struct devfs_node *node;
1011 	struct proc *p = curproc;
1012 	struct vnode *vp = ap->a_vp;
1013 	cdev_t dev = vp->v_rdev;
1014 	int error = 0;
1015 	int needrelock;
1016 
1017 	if (dev)
1018 		devfs_debug(DEVFS_DEBUG_DEBUG,
1019 			    "devfs_spec_close() called on %s! \n",
1020 			    dev->si_name);
1021 	else
1022 		devfs_debug(DEVFS_DEBUG_DEBUG,
1023 			    "devfs_spec_close() called, null vode!\n");
1024 
1025 	/*
1026 	 * A couple of hacks for devices and tty devices.  The
1027 	 * vnode ref count cannot be used to figure out the
1028 	 * last close, but we can use v_opencount now that
1029 	 * revoke works properly.
1030 	 *
1031 	 * Detect the last close on a controlling terminal and clear
1032 	 * the session (half-close).
1033 	 */
1034 	if (dev)
1035 		reference_dev(dev);
1036 
1037 	if (p && vp->v_opencount <= 1 && vp == p->p_session->s_ttyvp) {
1038 		p->p_session->s_ttyvp = NULL;
1039 		vrele(vp);
1040 	}
1041 
1042 	/*
1043 	 * Vnodes can be opened and closed multiple times.  Do not really
1044 	 * close the device unless (1) it is being closed forcibly,
1045 	 * (2) the device wants to track closes, or (3) this is the last
1046 	 * vnode doing its last close on the device.
1047 	 *
1048 	 * XXX the VXLOCK (force close) case can leave vnodes referencing
1049 	 * a closed device.  This might not occur now that our revoke is
1050 	 * fixed.
1051 	 */
1052 	devfs_debug(DEVFS_DEBUG_DEBUG, "devfs_spec_close() -1- \n");
1053 	if (dev && ((vp->v_flag & VRECLAIMED) ||
1054 	    (dev_dflags(dev) & D_TRACKCLOSE) ||
1055 	    (vp->v_opencount == 1))) {
1056 		/*
1057 		 * Ugly pty magic, to make pty devices disappear again once
1058 		 * they are closed.
1059 		 */
1060 		node = DEVFS_NODE(ap->a_vp);
1061 		if (node && (node->flags & DEVFS_PTY))
1062 			node->flags |= DEVFS_INVISIBLE;
1063 
1064 		/*
1065 		 * Unlock around dev_dclose(), unless the vnode is
1066 		 * undergoing a vgone/reclaim (during umount).
1067 		 */
1068 		needrelock = 0;
1069 		if ((vp->v_flag & VRECLAIMED) == 0 && vn_islocked(vp)) {
1070 			needrelock = 1;
1071 			vn_unlock(vp);
1072 		}
1073 
1074 		/*
1075 		 * WARNING!  If the device destroys itself the devfs node
1076 		 *	     can disappear here.
1077 		 *
1078 		 * WARNING!  vn_lock() will fail if the vp is in a VRECLAIM,
1079 		 *	     which can occur during umount.
1080 		 */
1081 		error = dev_dclose(dev, ap->a_fflag, S_IFCHR);
1082 		/* node is now stale */
1083 
1084 		if (needrelock) {
1085 			if (vn_lock(vp, LK_EXCLUSIVE | LK_RETRY) != 0) {
1086 				panic("devfs_spec_close: vnode %p "
1087 				      "unexpectedly could not be relocked",
1088 				      vp);
1089 			}
1090 		}
1091 	} else {
1092 		error = 0;
1093 	}
1094 	devfs_debug(DEVFS_DEBUG_DEBUG, "devfs_spec_close() -2- \n");
1095 
1096 	/*
1097 	 * Track the actual opens and closes on the vnode.  The last close
1098 	 * disassociates the rdev.  If the rdev is already disassociated or
1099 	 * the opencount is already 0, the vnode might have been revoked
1100 	 * and no further opencount tracking occurs.
1101 	 */
1102 	if (dev)
1103 		release_dev(dev);
1104 	if (vp->v_opencount > 0)
1105 		vop_stdclose(ap);
1106 	return(error);
1107 
1108 }
1109 
1110 
1111 static int
1112 devfs_fo_close(struct file *fp)
1113 {
1114 	struct vnode *vp = (struct vnode *)fp->f_data;
1115 	int error;
1116 
1117 	fp->f_ops = &badfileops;
1118 	error = vn_close(vp, fp->f_flag);
1119 
1120 	return (error);
1121 }
1122 
1123 
1124 /*
1125  * Device-optimized file table vnode read routine.
1126  *
1127  * This bypasses the VOP table and talks directly to the device.  Most
1128  * filesystems just route to specfs and can make this optimization.
1129  *
1130  * MPALMOSTSAFE - acquires mplock
1131  */
1132 static int
1133 devfs_fo_read(struct file *fp, struct uio *uio,
1134 		 struct ucred *cred, int flags)
1135 {
1136 	struct devfs_node *node;
1137 	struct vnode *vp;
1138 	int ioflag;
1139 	int error;
1140 	cdev_t dev;
1141 
1142 	KASSERT(uio->uio_td == curthread,
1143 		("uio_td %p is not td %p", uio->uio_td, curthread));
1144 
1145 	if (uio->uio_resid == 0)
1146 		return 0;
1147 
1148 	vp = (struct vnode *)fp->f_data;
1149 	if (vp == NULL || vp->v_type == VBAD)
1150 		return EBADF;
1151 
1152 	node = DEVFS_NODE(vp);
1153 
1154 	if ((dev = vp->v_rdev) == NULL)
1155 		return EBADF;
1156 
1157 	reference_dev(dev);
1158 
1159 	if ((flags & O_FOFFSET) == 0)
1160 		uio->uio_offset = fp->f_offset;
1161 
1162 	ioflag = 0;
1163 	if (flags & O_FBLOCKING) {
1164 		/* ioflag &= ~IO_NDELAY; */
1165 	} else if (flags & O_FNONBLOCKING) {
1166 		ioflag |= IO_NDELAY;
1167 	} else if (fp->f_flag & FNONBLOCK) {
1168 		ioflag |= IO_NDELAY;
1169 	}
1170 	if (flags & O_FBUFFERED) {
1171 		/* ioflag &= ~IO_DIRECT; */
1172 	} else if (flags & O_FUNBUFFERED) {
1173 		ioflag |= IO_DIRECT;
1174 	} else if (fp->f_flag & O_DIRECT) {
1175 		ioflag |= IO_DIRECT;
1176 	}
1177 	ioflag |= sequential_heuristic(uio, fp);
1178 
1179 	error = dev_dread(dev, uio, ioflag);
1180 
1181 	release_dev(dev);
1182 	if (node)
1183 		nanotime(&node->atime);
1184 	if ((flags & O_FOFFSET) == 0)
1185 		fp->f_offset = uio->uio_offset;
1186 	fp->f_nextoff = uio->uio_offset;
1187 
1188 	return (error);
1189 }
1190 
1191 
1192 static int
1193 devfs_fo_write(struct file *fp, struct uio *uio,
1194 		  struct ucred *cred, int flags)
1195 {
1196 	struct devfs_node *node;
1197 	struct vnode *vp;
1198 	int ioflag;
1199 	int error;
1200 	cdev_t dev;
1201 
1202 	KASSERT(uio->uio_td == curthread,
1203 		("uio_td %p is not p %p", uio->uio_td, curthread));
1204 
1205 	vp = (struct vnode *)fp->f_data;
1206 	if (vp == NULL || vp->v_type == VBAD)
1207 		return EBADF;
1208 
1209 	node = DEVFS_NODE(vp);
1210 
1211 	if (vp->v_type == VREG)
1212 		bwillwrite(uio->uio_resid);
1213 
1214 	vp = (struct vnode *)fp->f_data;
1215 
1216 	if ((dev = vp->v_rdev) == NULL)
1217 		return EBADF;
1218 
1219 	reference_dev(dev);
1220 
1221 	if ((flags & O_FOFFSET) == 0)
1222 		uio->uio_offset = fp->f_offset;
1223 
1224 	ioflag = IO_UNIT;
1225 	if (vp->v_type == VREG &&
1226 	   ((fp->f_flag & O_APPEND) || (flags & O_FAPPEND))) {
1227 		ioflag |= IO_APPEND;
1228 	}
1229 
1230 	if (flags & O_FBLOCKING) {
1231 		/* ioflag &= ~IO_NDELAY; */
1232 	} else if (flags & O_FNONBLOCKING) {
1233 		ioflag |= IO_NDELAY;
1234 	} else if (fp->f_flag & FNONBLOCK) {
1235 		ioflag |= IO_NDELAY;
1236 	}
1237 	if (flags & O_FBUFFERED) {
1238 		/* ioflag &= ~IO_DIRECT; */
1239 	} else if (flags & O_FUNBUFFERED) {
1240 		ioflag |= IO_DIRECT;
1241 	} else if (fp->f_flag & O_DIRECT) {
1242 		ioflag |= IO_DIRECT;
1243 	}
1244 	if (flags & O_FASYNCWRITE) {
1245 		/* ioflag &= ~IO_SYNC; */
1246 	} else if (flags & O_FSYNCWRITE) {
1247 		ioflag |= IO_SYNC;
1248 	} else if (fp->f_flag & O_FSYNC) {
1249 		ioflag |= IO_SYNC;
1250 	}
1251 
1252 	if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))
1253 		ioflag |= IO_SYNC;
1254 	ioflag |= sequential_heuristic(uio, fp);
1255 
1256 	error = dev_dwrite(dev, uio, ioflag);
1257 
1258 	release_dev(dev);
1259 	if (node) {
1260 		nanotime(&node->atime);
1261 		nanotime(&node->mtime);
1262 	}
1263 
1264 	if ((flags & O_FOFFSET) == 0)
1265 		fp->f_offset = uio->uio_offset;
1266 	fp->f_nextoff = uio->uio_offset;
1267 
1268 	return (error);
1269 }
1270 
1271 
1272 static int
1273 devfs_fo_stat(struct file *fp, struct stat *sb, struct ucred *cred)
1274 {
1275 	struct vnode *vp;
1276 	struct vattr vattr;
1277 	struct vattr *vap;
1278 	u_short mode;
1279 	cdev_t dev;
1280 	int error;
1281 
1282 	vp = (struct vnode *)fp->f_data;
1283 	if (vp == NULL || vp->v_type == VBAD)
1284 		return EBADF;
1285 
1286 	error = vn_stat(vp, sb, cred);
1287 	if (error)
1288 		return (error);
1289 
1290 	vap = &vattr;
1291 	error = VOP_GETATTR(vp, vap);
1292 	if (error)
1293 		return (error);
1294 
1295 	/*
1296 	 * Zero the spare stat fields
1297 	 */
1298 	sb->st_lspare = 0;
1299 	sb->st_qspare1 = 0;
1300 	sb->st_qspare2 = 0;
1301 
1302 	/*
1303 	 * Copy from vattr table ... or not in case it's a cloned device
1304 	 */
1305 	if (vap->va_fsid != VNOVAL)
1306 		sb->st_dev = vap->va_fsid;
1307 	else
1308 		sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0];
1309 
1310 	sb->st_ino = vap->va_fileid;
1311 
1312 	mode = vap->va_mode;
1313 	mode |= S_IFCHR;
1314 	sb->st_mode = mode;
1315 
1316 	if (vap->va_nlink > (nlink_t)-1)
1317 		sb->st_nlink = (nlink_t)-1;
1318 	else
1319 		sb->st_nlink = vap->va_nlink;
1320 
1321 	sb->st_uid = vap->va_uid;
1322 	sb->st_gid = vap->va_gid;
1323 	sb->st_rdev = dev2udev(DEVFS_NODE(vp)->d_dev);
1324 	sb->st_size = vap->va_bytes;
1325 	sb->st_atimespec = vap->va_atime;
1326 	sb->st_mtimespec = vap->va_mtime;
1327 	sb->st_ctimespec = vap->va_ctime;
1328 
1329 	/*
1330 	 * A VCHR and VBLK device may track the last access and last modified
1331 	 * time independantly of the filesystem.  This is particularly true
1332 	 * because device read and write calls may bypass the filesystem.
1333 	 */
1334 	if (vp->v_type == VCHR || vp->v_type == VBLK) {
1335 		dev = vp->v_rdev;
1336 		if (dev != NULL) {
1337 			if (dev->si_lastread) {
1338 				sb->st_atimespec.tv_sec = time_second +
1339 							  (time_uptime -
1340 							   dev->si_lastread);
1341 				sb->st_atimespec.tv_nsec = 0;
1342 			}
1343 			if (dev->si_lastwrite) {
1344 				sb->st_atimespec.tv_sec = time_second +
1345 							  (time_uptime -
1346 							   dev->si_lastwrite);
1347 				sb->st_atimespec.tv_nsec = 0;
1348 			}
1349 		}
1350 	}
1351 
1352         /*
1353 	 * According to www.opengroup.org, the meaning of st_blksize is
1354 	 *   "a filesystem-specific preferred I/O block size for this
1355 	 *    object.  In some filesystem types, this may vary from file
1356 	 *    to file"
1357 	 * Default to PAGE_SIZE after much discussion.
1358 	 */
1359 
1360 	sb->st_blksize = PAGE_SIZE;
1361 
1362 	sb->st_flags = vap->va_flags;
1363 
1364 	error = priv_check_cred(cred, PRIV_VFS_GENERATION, 0);
1365 	if (error)
1366 		sb->st_gen = 0;
1367 	else
1368 		sb->st_gen = (u_int32_t)vap->va_gen;
1369 
1370 	sb->st_blocks = vap->va_bytes / S_BLKSIZE;
1371 
1372 	return (0);
1373 }
1374 
1375 
1376 static int
1377 devfs_fo_kqfilter(struct file *fp, struct knote *kn)
1378 {
1379 	struct vnode *vp;
1380 	int error;
1381 	cdev_t dev;
1382 
1383 	vp = (struct vnode *)fp->f_data;
1384 	if (vp == NULL || vp->v_type == VBAD) {
1385 		error = EBADF;
1386 		goto done;
1387 	}
1388 	if ((dev = vp->v_rdev) == NULL) {
1389 		error = EBADF;
1390 		goto done;
1391 	}
1392 	reference_dev(dev);
1393 
1394 	error = dev_dkqfilter(dev, kn);
1395 
1396 	release_dev(dev);
1397 
1398 done:
1399 	return (error);
1400 }
1401 
1402 /*
1403  * MPALMOSTSAFE - acquires mplock
1404  */
1405 static int
1406 devfs_fo_ioctl(struct file *fp, u_long com, caddr_t data,
1407 		  struct ucred *ucred, struct sysmsg *msg)
1408 {
1409 #if 0
1410 	struct devfs_node *node;
1411 #endif
1412 	struct vnode *vp;
1413 	struct vnode *ovp;
1414 	cdev_t	dev;
1415 	int error;
1416 	struct fiodname_args *name_args;
1417 	size_t namlen;
1418 	const char *name;
1419 
1420 	vp = ((struct vnode *)fp->f_data);
1421 
1422 	if ((dev = vp->v_rdev) == NULL)
1423 		return EBADF;		/* device was revoked */
1424 
1425 	reference_dev(dev);
1426 
1427 #if 0
1428 	node = DEVFS_NODE(vp);
1429 #endif
1430 
1431 	devfs_debug(DEVFS_DEBUG_DEBUG,
1432 		    "devfs_fo_ioctl() called! for dev %s\n",
1433 		    dev->si_name);
1434 
1435 	if (com == FIODTYPE) {
1436 		*(int *)data = dev_dflags(dev) & D_TYPEMASK;
1437 		error = 0;
1438 		goto out;
1439 	} else if (com == FIODNAME) {
1440 		name_args = (struct fiodname_args *)data;
1441 		name = dev->si_name;
1442 		namlen = strlen(name) + 1;
1443 
1444 		devfs_debug(DEVFS_DEBUG_DEBUG,
1445 			    "ioctl, got: FIODNAME for %s\n", name);
1446 
1447 		if (namlen <= name_args->len)
1448 			error = copyout(dev->si_name, name_args->name, namlen);
1449 		else
1450 			error = EINVAL;
1451 
1452 		devfs_debug(DEVFS_DEBUG_DEBUG,
1453 			    "ioctl stuff: error: %d\n", error);
1454 		goto out;
1455 	}
1456 
1457 	error = dev_dioctl(dev, com, data, fp->f_flag, ucred, msg);
1458 
1459 #if 0
1460 	if (node) {
1461 		nanotime(&node->atime);
1462 		nanotime(&node->mtime);
1463 	}
1464 #endif
1465 	if (com == TIOCSCTTY) {
1466 		devfs_debug(DEVFS_DEBUG_DEBUG,
1467 			    "devfs_fo_ioctl: got TIOCSCTTY on %s\n",
1468 			    dev->si_name);
1469 	}
1470 	if (error == 0 && com == TIOCSCTTY) {
1471 		struct proc *p = curthread->td_proc;
1472 		struct session *sess;
1473 
1474 		devfs_debug(DEVFS_DEBUG_DEBUG,
1475 			    "devfs_fo_ioctl: dealing with TIOCSCTTY on %s\n",
1476 			    dev->si_name);
1477 		if (p == NULL) {
1478 			error = ENOTTY;
1479 			goto out;
1480 		}
1481 		sess = p->p_session;
1482 
1483 		/*
1484 		 * Do nothing if reassigning same control tty
1485 		 */
1486 		if (sess->s_ttyvp == vp) {
1487 			error = 0;
1488 			goto out;
1489 		}
1490 
1491 		/*
1492 		 * Get rid of reference to old control tty
1493 		 */
1494 		ovp = sess->s_ttyvp;
1495 		vref(vp);
1496 		sess->s_ttyvp = vp;
1497 		if (ovp)
1498 			vrele(ovp);
1499 	}
1500 
1501 out:
1502 	release_dev(dev);
1503 	devfs_debug(DEVFS_DEBUG_DEBUG, "devfs_fo_ioctl() finished! \n");
1504 	return (error);
1505 }
1506 
1507 
1508 static int
1509 devfs_spec_fsync(struct vop_fsync_args *ap)
1510 {
1511 	struct vnode *vp = ap->a_vp;
1512 	int error;
1513 
1514 	if (!vn_isdisk(vp, NULL))
1515 		return (0);
1516 
1517 	/*
1518 	 * Flush all dirty buffers associated with a block device.
1519 	 */
1520 	error = vfsync(vp, ap->a_waitfor, 10000, NULL, NULL);
1521 	return (error);
1522 }
1523 
1524 static int
1525 devfs_spec_read(struct vop_read_args *ap)
1526 {
1527 	struct devfs_node *node;
1528 	struct vnode *vp;
1529 	struct uio *uio;
1530 	cdev_t dev;
1531 	int error;
1532 
1533 	vp = ap->a_vp;
1534 	dev = vp->v_rdev;
1535 	uio = ap->a_uio;
1536 	node = DEVFS_NODE(vp);
1537 
1538 	if (dev == NULL)		/* device was revoked */
1539 		return (EBADF);
1540 	if (uio->uio_resid == 0)
1541 		return (0);
1542 
1543 	vn_unlock(vp);
1544 	error = dev_dread(dev, uio, ap->a_ioflag);
1545 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1546 
1547 	if (node)
1548 		nanotime(&node->atime);
1549 
1550 	return (error);
1551 }
1552 
1553 /*
1554  * Vnode op for write
1555  *
1556  * spec_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
1557  *	      struct ucred *a_cred)
1558  */
1559 static int
1560 devfs_spec_write(struct vop_write_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 	KKASSERT(uio->uio_segflg != UIO_NOCOPY);
1574 
1575 	if (dev == NULL)		/* device was revoked */
1576 		return (EBADF);
1577 
1578 	vn_unlock(vp);
1579 	error = dev_dwrite(dev, uio, ap->a_ioflag);
1580 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1581 
1582 	if (node) {
1583 		nanotime(&node->atime);
1584 		nanotime(&node->mtime);
1585 	}
1586 
1587 	return (error);
1588 }
1589 
1590 /*
1591  * Device ioctl operation.
1592  *
1593  * spec_ioctl(struct vnode *a_vp, int a_command, caddr_t a_data,
1594  *	      int a_fflag, struct ucred *a_cred, struct sysmsg *msg)
1595  */
1596 static int
1597 devfs_spec_ioctl(struct vop_ioctl_args *ap)
1598 {
1599 	struct vnode *vp = ap->a_vp;
1600 #if 0
1601 	struct devfs_node *node;
1602 #endif
1603 	cdev_t dev;
1604 
1605 	if ((dev = vp->v_rdev) == NULL)
1606 		return (EBADF);		/* device was revoked */
1607 #if 0
1608 	node = DEVFS_NODE(vp);
1609 
1610 	if (node) {
1611 		nanotime(&node->atime);
1612 		nanotime(&node->mtime);
1613 	}
1614 #endif
1615 
1616 	return (dev_dioctl(dev, ap->a_command, ap->a_data, ap->a_fflag,
1617 			   ap->a_cred, ap->a_sysmsg));
1618 }
1619 
1620 /*
1621  * spec_kqfilter(struct vnode *a_vp, struct knote *a_kn)
1622  */
1623 /* ARGSUSED */
1624 static int
1625 devfs_spec_kqfilter(struct vop_kqfilter_args *ap)
1626 {
1627 	struct vnode *vp = ap->a_vp;
1628 #if 0
1629 	struct devfs_node *node;
1630 #endif
1631 	cdev_t dev;
1632 
1633 	if ((dev = vp->v_rdev) == NULL)
1634 		return (EBADF);		/* device was revoked (EBADF) */
1635 #if 0
1636 	node = DEVFS_NODE(vp);
1637 
1638 	if (node)
1639 		nanotime(&node->atime);
1640 #endif
1641 
1642 	return (dev_dkqfilter(dev, ap->a_kn));
1643 }
1644 
1645 /*
1646  * Convert a vnode strategy call into a device strategy call.  Vnode strategy
1647  * calls are not limited to device DMA limits so we have to deal with the
1648  * case.
1649  *
1650  * spec_strategy(struct vnode *a_vp, struct bio *a_bio)
1651  */
1652 static int
1653 devfs_spec_strategy(struct vop_strategy_args *ap)
1654 {
1655 	struct bio *bio = ap->a_bio;
1656 	struct buf *bp = bio->bio_buf;
1657 	struct buf *nbp;
1658 	struct vnode *vp;
1659 	struct mount *mp;
1660 	int chunksize;
1661 	int maxiosize;
1662 
1663 	if (bp->b_cmd != BUF_CMD_READ && LIST_FIRST(&bp->b_dep) != NULL)
1664 		buf_start(bp);
1665 
1666 	/*
1667 	 * Collect statistics on synchronous and asynchronous read
1668 	 * and write counts for disks that have associated filesystems.
1669 	 */
1670 	vp = ap->a_vp;
1671 	KKASSERT(vp->v_rdev != NULL);	/* XXX */
1672 	if (vn_isdisk(vp, NULL) && (mp = vp->v_rdev->si_mountpoint) != NULL) {
1673 		if (bp->b_cmd == BUF_CMD_READ) {
1674 			if (bp->b_flags & BIO_SYNC)
1675 				mp->mnt_stat.f_syncreads++;
1676 			else
1677 				mp->mnt_stat.f_asyncreads++;
1678 		} else {
1679 			if (bp->b_flags & BIO_SYNC)
1680 				mp->mnt_stat.f_syncwrites++;
1681 			else
1682 				mp->mnt_stat.f_asyncwrites++;
1683 		}
1684 	}
1685 
1686         /*
1687          * Device iosize limitations only apply to read and write.  Shortcut
1688          * the I/O if it fits.
1689          */
1690 	if ((maxiosize = vp->v_rdev->si_iosize_max) == 0) {
1691 		devfs_debug(DEVFS_DEBUG_DEBUG,
1692 			    "%s: si_iosize_max not set!\n",
1693 			    dev_dname(vp->v_rdev));
1694 		maxiosize = MAXPHYS;
1695 	}
1696 #if SPEC_CHAIN_DEBUG & 2
1697 	maxiosize = 4096;
1698 #endif
1699         if (bp->b_bcount <= maxiosize ||
1700             (bp->b_cmd != BUF_CMD_READ && bp->b_cmd != BUF_CMD_WRITE)) {
1701                 dev_dstrategy_chain(vp->v_rdev, bio);
1702                 return (0);
1703         }
1704 
1705 	/*
1706 	 * Clone the buffer and set up an I/O chain to chunk up the I/O.
1707 	 */
1708 	nbp = kmalloc(sizeof(*bp), M_DEVBUF, M_INTWAIT|M_ZERO);
1709 	initbufbio(nbp);
1710 	buf_dep_init(nbp);
1711 	BUF_LOCK(nbp, LK_EXCLUSIVE);
1712 	BUF_KERNPROC(nbp);
1713 	nbp->b_vp = vp;
1714 	nbp->b_flags = B_PAGING | (bp->b_flags & B_BNOCLIP);
1715 	nbp->b_data = bp->b_data;
1716 	nbp->b_bio1.bio_done = devfs_spec_strategy_done;
1717 	nbp->b_bio1.bio_offset = bio->bio_offset;
1718 	nbp->b_bio1.bio_caller_info1.ptr = bio;
1719 
1720 	/*
1721 	 * Start the first transfer
1722 	 */
1723 	if (vn_isdisk(vp, NULL))
1724 		chunksize = vp->v_rdev->si_bsize_phys;
1725 	else
1726 		chunksize = DEV_BSIZE;
1727 	chunksize = maxiosize / chunksize * chunksize;
1728 #if SPEC_CHAIN_DEBUG & 1
1729 	devfs_debug(DEVFS_DEBUG_DEBUG,
1730 		    "spec_strategy chained I/O chunksize=%d\n",
1731 		    chunksize);
1732 #endif
1733 	nbp->b_cmd = bp->b_cmd;
1734 	nbp->b_bcount = chunksize;
1735 	nbp->b_bufsize = chunksize;	/* used to detect a short I/O */
1736 	nbp->b_bio1.bio_caller_info2.index = chunksize;
1737 
1738 #if SPEC_CHAIN_DEBUG & 1
1739 	devfs_debug(DEVFS_DEBUG_DEBUG,
1740 		    "spec_strategy: chain %p offset %d/%d bcount %d\n",
1741 		    bp, 0, bp->b_bcount, nbp->b_bcount);
1742 #endif
1743 
1744 	dev_dstrategy(vp->v_rdev, &nbp->b_bio1);
1745 
1746 	if (DEVFS_NODE(vp)) {
1747 		nanotime(&DEVFS_NODE(vp)->atime);
1748 		nanotime(&DEVFS_NODE(vp)->mtime);
1749 	}
1750 
1751 	return (0);
1752 }
1753 
1754 /*
1755  * Chunked up transfer completion routine - chain transfers until done
1756  *
1757  * NOTE: MPSAFE callback.
1758  */
1759 static
1760 void
1761 devfs_spec_strategy_done(struct bio *nbio)
1762 {
1763 	struct buf *nbp = nbio->bio_buf;
1764 	struct bio *bio = nbio->bio_caller_info1.ptr;	/* original bio */
1765 	struct buf *bp = bio->bio_buf;			/* original bp */
1766 	int chunksize = nbio->bio_caller_info2.index;	/* chunking */
1767 	int boffset = nbp->b_data - bp->b_data;
1768 
1769 	if (nbp->b_flags & B_ERROR) {
1770 		/*
1771 		 * An error terminates the chain, propogate the error back
1772 		 * to the original bp
1773 		 */
1774 		bp->b_flags |= B_ERROR;
1775 		bp->b_error = nbp->b_error;
1776 		bp->b_resid = bp->b_bcount - boffset +
1777 			      (nbp->b_bcount - nbp->b_resid);
1778 #if SPEC_CHAIN_DEBUG & 1
1779 		devfs_debug(DEVFS_DEBUG_DEBUG,
1780 			    "spec_strategy: chain %p error %d bcount %d/%d\n",
1781 			    bp, bp->b_error, bp->b_bcount,
1782 			    bp->b_bcount - bp->b_resid);
1783 #endif
1784 	} else if (nbp->b_resid) {
1785 		/*
1786 		 * A short read or write terminates the chain
1787 		 */
1788 		bp->b_error = nbp->b_error;
1789 		bp->b_resid = bp->b_bcount - boffset +
1790 			      (nbp->b_bcount - nbp->b_resid);
1791 #if SPEC_CHAIN_DEBUG & 1
1792 		devfs_debug(DEVFS_DEBUG_DEBUG,
1793 			    "spec_strategy: chain %p short read(1) "
1794 			    "bcount %d/%d\n",
1795 			    bp, bp->b_bcount - bp->b_resid, bp->b_bcount);
1796 #endif
1797 	} else if (nbp->b_bcount != nbp->b_bufsize) {
1798 		/*
1799 		 * A short read or write can also occur by truncating b_bcount
1800 		 */
1801 #if SPEC_CHAIN_DEBUG & 1
1802 		devfs_debug(DEVFS_DEBUG_DEBUG,
1803 			    "spec_strategy: chain %p short read(2) "
1804 			    "bcount %d/%d\n",
1805 			    bp, nbp->b_bcount + boffset, bp->b_bcount);
1806 #endif
1807 		bp->b_error = 0;
1808 		bp->b_bcount = nbp->b_bcount + boffset;
1809 		bp->b_resid = nbp->b_resid;
1810 	} else if (nbp->b_bcount + boffset == bp->b_bcount) {
1811 		/*
1812 		 * No more data terminates the chain
1813 		 */
1814 #if SPEC_CHAIN_DEBUG & 1
1815 		devfs_debug(DEVFS_DEBUG_DEBUG,
1816 			    "spec_strategy: chain %p finished bcount %d\n",
1817 			    bp, bp->b_bcount);
1818 #endif
1819 		bp->b_error = 0;
1820 		bp->b_resid = 0;
1821 	} else {
1822 		/*
1823 		 * Continue the chain
1824 		 */
1825 		boffset += nbp->b_bcount;
1826 		nbp->b_data = bp->b_data + boffset;
1827 		nbp->b_bcount = bp->b_bcount - boffset;
1828 		if (nbp->b_bcount > chunksize)
1829 			nbp->b_bcount = chunksize;
1830 		nbp->b_bio1.bio_done = devfs_spec_strategy_done;
1831 		nbp->b_bio1.bio_offset = bio->bio_offset + boffset;
1832 
1833 #if SPEC_CHAIN_DEBUG & 1
1834 		devfs_debug(DEVFS_DEBUG_DEBUG,
1835 			    "spec_strategy: chain %p offset %d/%d bcount %d\n",
1836 			    bp, boffset, bp->b_bcount, nbp->b_bcount);
1837 #endif
1838 
1839 		dev_dstrategy(nbp->b_vp->v_rdev, &nbp->b_bio1);
1840 		return;
1841 	}
1842 
1843 	/*
1844 	 * Fall through to here on termination.  biodone(bp) and
1845 	 * clean up and free nbp.
1846 	 */
1847 	biodone(bio);
1848 	BUF_UNLOCK(nbp);
1849 	uninitbufbio(nbp);
1850 	kfree(nbp, M_DEVBUF);
1851 }
1852 
1853 /*
1854  * spec_freeblks(struct vnode *a_vp, daddr_t a_addr, daddr_t a_length)
1855  */
1856 static int
1857 devfs_spec_freeblks(struct vop_freeblks_args *ap)
1858 {
1859 	struct buf *bp;
1860 
1861 	/*
1862 	 * XXX: This assumes that strategy does the deed right away.
1863 	 * XXX: this may not be TRTTD.
1864 	 */
1865 	KKASSERT(ap->a_vp->v_rdev != NULL);
1866 	if ((ap->a_vp->v_rdev->si_flags & SI_CANFREE) == 0)
1867 		return (0);
1868 	bp = geteblk(ap->a_length);
1869 	bp->b_cmd = BUF_CMD_FREEBLKS;
1870 	bp->b_bio1.bio_offset = ap->a_offset;
1871 	bp->b_bcount = ap->a_length;
1872 	dev_dstrategy(ap->a_vp->v_rdev, &bp->b_bio1);
1873 	return (0);
1874 }
1875 
1876 /*
1877  * Implement degenerate case where the block requested is the block
1878  * returned, and assume that the entire device is contiguous in regards
1879  * to the contiguous block range (runp and runb).
1880  *
1881  * spec_bmap(struct vnode *a_vp, off_t a_loffset,
1882  *	     off_t *a_doffsetp, int *a_runp, int *a_runb)
1883  */
1884 static int
1885 devfs_spec_bmap(struct vop_bmap_args *ap)
1886 {
1887 	if (ap->a_doffsetp != NULL)
1888 		*ap->a_doffsetp = ap->a_loffset;
1889 	if (ap->a_runp != NULL)
1890 		*ap->a_runp = MAXBSIZE;
1891 	if (ap->a_runb != NULL) {
1892 		if (ap->a_loffset < MAXBSIZE)
1893 			*ap->a_runb = (int)ap->a_loffset;
1894 		else
1895 			*ap->a_runb = MAXBSIZE;
1896 	}
1897 	return (0);
1898 }
1899 
1900 
1901 /*
1902  * Special device advisory byte-level locks.
1903  *
1904  * spec_advlock(struct vnode *a_vp, caddr_t a_id, int a_op,
1905  *		struct flock *a_fl, int a_flags)
1906  */
1907 /* ARGSUSED */
1908 static int
1909 devfs_spec_advlock(struct vop_advlock_args *ap)
1910 {
1911 	return ((ap->a_flags & F_POSIX) ? EINVAL : EOPNOTSUPP);
1912 }
1913 
1914 /*
1915  * NOTE: MPSAFE callback.
1916  */
1917 static void
1918 devfs_spec_getpages_iodone(struct bio *bio)
1919 {
1920 	bio->bio_buf->b_cmd = BUF_CMD_DONE;
1921 	wakeup(bio->bio_buf);
1922 }
1923 
1924 /*
1925  * spec_getpages() - get pages associated with device vnode.
1926  *
1927  * Note that spec_read and spec_write do not use the buffer cache, so we
1928  * must fully implement getpages here.
1929  */
1930 static int
1931 devfs_spec_getpages(struct vop_getpages_args *ap)
1932 {
1933 	vm_offset_t kva;
1934 	int error;
1935 	int i, pcount, size;
1936 	struct buf *bp;
1937 	vm_page_t m;
1938 	vm_ooffset_t offset;
1939 	int toff, nextoff, nread;
1940 	struct vnode *vp = ap->a_vp;
1941 	int blksiz;
1942 	int gotreqpage;
1943 
1944 	error = 0;
1945 	pcount = round_page(ap->a_count) / PAGE_SIZE;
1946 
1947 	/*
1948 	 * Calculate the offset of the transfer and do sanity check.
1949 	 */
1950 	offset = IDX_TO_OFF(ap->a_m[0]->pindex) + ap->a_offset;
1951 
1952 	/*
1953 	 * Round up physical size for real devices.  We cannot round using
1954 	 * v_mount's block size data because v_mount has nothing to do with
1955 	 * the device.  i.e. it's usually '/dev'.  We need the physical block
1956 	 * size for the device itself.
1957 	 *
1958 	 * We can't use v_rdev->si_mountpoint because it only exists when the
1959 	 * block device is mounted.  However, we can use v_rdev.
1960 	 */
1961 	if (vn_isdisk(vp, NULL))
1962 		blksiz = vp->v_rdev->si_bsize_phys;
1963 	else
1964 		blksiz = DEV_BSIZE;
1965 
1966 	size = (ap->a_count + blksiz - 1) & ~(blksiz - 1);
1967 
1968 	bp = getpbuf_kva(NULL);
1969 	kva = (vm_offset_t)bp->b_data;
1970 
1971 	/*
1972 	 * Map the pages to be read into the kva.
1973 	 */
1974 	pmap_qenter(kva, ap->a_m, pcount);
1975 
1976 	/* Build a minimal buffer header. */
1977 	bp->b_cmd = BUF_CMD_READ;
1978 	bp->b_bcount = size;
1979 	bp->b_resid = 0;
1980 	bsetrunningbufspace(bp, size);
1981 
1982 	bp->b_bio1.bio_offset = offset;
1983 	bp->b_bio1.bio_done = devfs_spec_getpages_iodone;
1984 
1985 	mycpu->gd_cnt.v_vnodein++;
1986 	mycpu->gd_cnt.v_vnodepgsin += pcount;
1987 
1988 	/* Do the input. */
1989 	vn_strategy(ap->a_vp, &bp->b_bio1);
1990 
1991 	crit_enter();
1992 
1993 	/* We definitely need to be at splbio here. */
1994 	while (bp->b_cmd != BUF_CMD_DONE)
1995 		tsleep(bp, 0, "spread", 0);
1996 
1997 	crit_exit();
1998 
1999 	if (bp->b_flags & B_ERROR) {
2000 		if (bp->b_error)
2001 			error = bp->b_error;
2002 		else
2003 			error = EIO;
2004 	}
2005 
2006 	/*
2007 	 * If EOF is encountered we must zero-extend the result in order
2008 	 * to ensure that the page does not contain garabge.  When no
2009 	 * error occurs, an early EOF is indicated if b_bcount got truncated.
2010 	 * b_resid is relative to b_bcount and should be 0, but some devices
2011 	 * might indicate an EOF with b_resid instead of truncating b_bcount.
2012 	 */
2013 	nread = bp->b_bcount - bp->b_resid;
2014 	if (nread < ap->a_count)
2015 		bzero((caddr_t)kva + nread, ap->a_count - nread);
2016 	pmap_qremove(kva, pcount);
2017 
2018 	gotreqpage = 0;
2019 	for (i = 0, toff = 0; i < pcount; i++, toff = nextoff) {
2020 		nextoff = toff + PAGE_SIZE;
2021 		m = ap->a_m[i];
2022 
2023 		m->flags &= ~PG_ZERO;
2024 
2025 		/*
2026 		 * NOTE: vm_page_undirty/clear_dirty etc do not clear the
2027 		 *	 pmap modified bit.  pmap modified bit should have
2028 		 *	 already been cleared.
2029 		 */
2030 		if (nextoff <= nread) {
2031 			m->valid = VM_PAGE_BITS_ALL;
2032 			vm_page_undirty(m);
2033 		} else if (toff < nread) {
2034 			/*
2035 			 * Since this is a VM request, we have to supply the
2036 			 * unaligned offset to allow vm_page_set_valid()
2037 			 * to zero sub-DEV_BSIZE'd portions of the page.
2038 			 */
2039 			vm_page_set_valid(m, 0, nread - toff);
2040 			vm_page_clear_dirty_end_nonincl(m, 0, nread - toff);
2041 		} else {
2042 			m->valid = 0;
2043 			vm_page_undirty(m);
2044 		}
2045 
2046 		if (i != ap->a_reqpage) {
2047 			/*
2048 			 * Just in case someone was asking for this page we
2049 			 * now tell them that it is ok to use.
2050 			 */
2051 			if (!error || (m->valid == VM_PAGE_BITS_ALL)) {
2052 				if (m->valid) {
2053 					if (m->flags & PG_REFERENCED) {
2054 						vm_page_activate(m);
2055 					} else {
2056 						vm_page_deactivate(m);
2057 					}
2058 					vm_page_wakeup(m);
2059 				} else {
2060 					vm_page_free(m);
2061 				}
2062 			} else {
2063 				vm_page_free(m);
2064 			}
2065 		} else if (m->valid) {
2066 			gotreqpage = 1;
2067 			/*
2068 			 * Since this is a VM request, we need to make the
2069 			 * entire page presentable by zeroing invalid sections.
2070 			 */
2071 			if (m->valid != VM_PAGE_BITS_ALL)
2072 			    vm_page_zero_invalid(m, FALSE);
2073 		}
2074 	}
2075 	if (!gotreqpage) {
2076 		m = ap->a_m[ap->a_reqpage];
2077 		devfs_debug(DEVFS_DEBUG_WARNING,
2078 	    "spec_getpages:(%s) I/O read failure: (error=%d) bp %p vp %p\n",
2079 			devtoname(vp->v_rdev), error, bp, bp->b_vp);
2080 		devfs_debug(DEVFS_DEBUG_WARNING,
2081 	    "               size: %d, resid: %d, a_count: %d, valid: 0x%x\n",
2082 		    size, bp->b_resid, ap->a_count, m->valid);
2083 		devfs_debug(DEVFS_DEBUG_WARNING,
2084 	    "               nread: %d, reqpage: %d, pindex: %lu, pcount: %d\n",
2085 		    nread, ap->a_reqpage, (u_long)m->pindex, pcount);
2086 		/*
2087 		 * Free the buffer header back to the swap buffer pool.
2088 		 */
2089 		relpbuf(bp, NULL);
2090 		return VM_PAGER_ERROR;
2091 	}
2092 	/*
2093 	 * Free the buffer header back to the swap buffer pool.
2094 	 */
2095 	relpbuf(bp, NULL);
2096 	if (DEVFS_NODE(ap->a_vp))
2097 		nanotime(&DEVFS_NODE(ap->a_vp)->mtime);
2098 	return VM_PAGER_OK;
2099 }
2100 
2101 static __inline
2102 int
2103 sequential_heuristic(struct uio *uio, struct file *fp)
2104 {
2105 	/*
2106 	 * Sequential heuristic - detect sequential operation
2107 	 */
2108 	if ((uio->uio_offset == 0 && fp->f_seqcount > 0) ||
2109 	    uio->uio_offset == fp->f_nextoff) {
2110 		/*
2111 		 * XXX we assume that the filesystem block size is
2112 		 * the default.  Not true, but still gives us a pretty
2113 		 * good indicator of how sequential the read operations
2114 		 * are.
2115 		 */
2116 		int tmpseq = fp->f_seqcount;
2117 
2118 		tmpseq += (uio->uio_resid + BKVASIZE - 1) / BKVASIZE;
2119 		if (tmpseq > IO_SEQMAX)
2120 			tmpseq = IO_SEQMAX;
2121 		fp->f_seqcount = tmpseq;
2122 		return(fp->f_seqcount << IO_SEQSHIFT);
2123 	}
2124 
2125 	/*
2126 	 * Not sequential, quick draw-down of seqcount
2127 	 */
2128 	if (fp->f_seqcount > 1)
2129 		fp->f_seqcount = 1;
2130 	else
2131 		fp->f_seqcount = 0;
2132 	return(0);
2133 }
2134