xref: /dragonfly/sys/kern/subr_disk.c (revision 28feafc7)
1 /*
2  * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  * ----------------------------------------------------------------------------
35  * "THE BEER-WARE LICENSE" (Revision 42):
36  * <phk@FreeBSD.ORG> wrote this file.  As long as you retain this notice you
37  * can do whatever you want with this stuff. If we meet some day, and you think
38  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
39  * ----------------------------------------------------------------------------
40  *
41  * Copyright (c) 1982, 1986, 1988, 1993
42  *	The Regents of the University of California.  All rights reserved.
43  * (c) UNIX System Laboratories, Inc.
44  * All or some portions of this file are derived from material licensed
45  * to the University of California by American Telephone and Telegraph
46  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
47  * the permission of UNIX System Laboratories, Inc.
48  *
49  * Redistribution and use in source and binary forms, with or without
50  * modification, are permitted provided that the following conditions
51  * are met:
52  * 1. Redistributions of source code must retain the above copyright
53  *    notice, this list of conditions and the following disclaimer.
54  * 2. Redistributions in binary form must reproduce the above copyright
55  *    notice, this list of conditions and the following disclaimer in the
56  *    documentation and/or other materials provided with the distribution.
57  * 3. All advertising materials mentioning features or use of this software
58  *    must display the following acknowledgement:
59  *	This product includes software developed by the University of
60  *	California, Berkeley and its contributors.
61  * 4. Neither the name of the University nor the names of its contributors
62  *    may be used to endorse or promote products derived from this software
63  *    without specific prior written permission.
64  *
65  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
66  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
67  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
68  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
69  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
70  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
71  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
72  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
73  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
74  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
75  * SUCH DAMAGE.
76  *
77  *	@(#)ufs_disksubr.c	8.5 (Berkeley) 1/21/94
78  * $FreeBSD: src/sys/kern/subr_disk.c,v 1.20.2.6 2001/10/05 07:14:57 peter Exp $
79  * $FreeBSD: src/sys/ufs/ufs/ufs_disksubr.c,v 1.44.2.3 2001/03/05 05:42:19 obrien Exp $
80  * $DragonFly: src/sys/kern/subr_disk.c,v 1.33 2007/05/19 07:05:25 dillon Exp $
81  */
82 
83 #include <sys/param.h>
84 #include <sys/systm.h>
85 #include <sys/kernel.h>
86 #include <sys/proc.h>
87 #include <sys/sysctl.h>
88 #include <sys/buf.h>
89 #include <sys/conf.h>
90 #include <sys/disklabel.h>
91 #include <sys/diskslice.h>
92 #include <sys/disk.h>
93 #include <sys/malloc.h>
94 #include <sys/sysctl.h>
95 #include <machine/md_var.h>
96 #include <sys/ctype.h>
97 #include <sys/syslog.h>
98 #include <sys/device.h>
99 #include <sys/msgport.h>
100 #include <sys/msgport2.h>
101 #include <sys/buf2.h>
102 
103 static MALLOC_DEFINE(M_DISK, "disk", "disk data");
104 
105 static d_open_t diskopen;
106 static d_close_t diskclose;
107 static d_ioctl_t diskioctl;
108 static d_strategy_t diskstrategy;
109 static d_psize_t diskpsize;
110 static d_clone_t diskclone;
111 static d_dump_t diskdump;
112 
113 static LIST_HEAD(, disk) disklist = LIST_HEAD_INITIALIZER(&disklist);
114 
115 static struct dev_ops disk_ops = {
116 	{ "disk" },
117 	.d_open = diskopen,
118 	.d_close = diskclose,
119 	.d_read = physread,
120 	.d_write = physwrite,
121 	.d_ioctl = diskioctl,
122 	.d_strategy = diskstrategy,
123 	.d_dump = diskdump,
124 	.d_psize = diskpsize,
125 	.d_clone = diskclone
126 };
127 
128 /*
129  * Create a raw device for the dev_ops template (which is returned).  Also
130  * create a slice and unit managed disk and overload the user visible
131  * device space with it.
132  *
133  * NOTE: The returned raw device is NOT a slice and unit managed device.
134  * It is an actual raw device representing the raw disk as specified by
135  * the passed dev_ops.  The disk layer not only returns such a raw device,
136  * it also uses it internally when passing (modified) commands through.
137  */
138 cdev_t
139 disk_create(int unit, struct disk *dp, struct dev_ops *raw_ops)
140 {
141 	cdev_t rawdev;
142 	struct dev_ops *dev_ops;
143 
144 	/*
145 	 * Create the raw backing device
146 	 */
147 	compile_dev_ops(raw_ops);
148 	rawdev = make_dev(raw_ops, dkmakewholedisk(unit),
149 			    UID_ROOT, GID_OPERATOR, 0640,
150 			    "%s%d", raw_ops->head.name, unit);
151 
152 	bzero(dp, sizeof(*dp));
153 
154 	/*
155 	 * We install a custom cdevsw rather then the passed cdevsw,
156 	 * and save our disk structure in d_data so we can get at it easily
157 	 * without any complex cloning code.
158 	 */
159 	dev_ops = dev_ops_add_override(rawdev, &disk_ops,
160 				       dkunitmask(), dkmakeunit(unit));
161 	dev_ops->head.data = dp;
162 
163 	dp->d_rawdev = rawdev;
164 	dp->d_raw_ops = raw_ops;
165 	dp->d_dev_ops = dev_ops;
166 	dp->d_cdev = make_dev(dev_ops,
167 			    dkmakewholedisk(unit),
168 			    UID_ROOT, GID_OPERATOR, 0640,
169 			    "%s%d", dev_ops->head.name, unit);
170 
171 	LIST_INSERT_HEAD(&disklist, dp, d_list);
172 	return (dp->d_rawdev);
173 }
174 
175 /*
176  * Disk drivers must call this routine when media parameters are available
177  * or have changed.
178  */
179 void
180 disk_setdiskinfo(struct disk *disk, struct disk_info *info)
181 {
182 	bcopy(info, &disk->d_info, sizeof(disk->d_info));
183 	info = &disk->d_info;
184 
185 	KKASSERT(info->d_media_size == 0 || info->d_media_blksize == 0);
186 	if (info->d_media_size == 0 && info->d_media_blocks) {
187 		info->d_media_size = (u_int64_t)info->d_media_blocks *
188 				     info->d_media_blksize;
189 	} else if (info->d_media_size && info->d_media_blocks == 0 &&
190 		   info->d_media_blksize) {
191 		info->d_media_blocks = info->d_media_size /
192 				       info->d_media_blksize;
193 	}
194 }
195 
196 /*
197  * This routine is called when an adapter detaches.  The higher level
198  * managed disk device is destroyed while the lower level raw device is
199  * released.
200  */
201 void
202 disk_destroy(struct disk *disk)
203 {
204 	if (disk->d_dev_ops) {
205 	    dev_ops_remove(disk->d_dev_ops, dkunitmask(),
206 			    dkmakeunit(dkunit(disk->d_cdev)));
207 	    LIST_REMOVE(disk, d_list);
208 	}
209 	if (disk->d_raw_ops) {
210 	    destroy_all_devs(disk->d_raw_ops, dkunitmask(),
211 			    dkmakeunit(dkunit(disk->d_rawdev)));
212 	}
213 	bzero(disk, sizeof(*disk));
214 }
215 
216 int
217 disk_dumpcheck(cdev_t dev, u_int64_t *count, u_int64_t *blkno, u_int *secsize)
218 {
219 	struct partinfo pinfo;
220 	int error;
221 
222 	bzero(&pinfo, sizeof(pinfo));
223 	error = dev_dioctl(dev, DIOCGPART, (void *)&pinfo, 0, proc0.p_ucred);
224 	if (error)
225 		return (error);
226 	if (pinfo.media_blksize == 0)
227 		return (ENXIO);
228 	*count = (u_int64_t)Maxmem * PAGE_SIZE / pinfo.media_blksize;
229 	if (dumplo64 < pinfo.skip_bsdlabel ||
230 	    dumplo64 + *count > pinfo.media_blocks) {
231 		return (ENOSPC);
232 	}
233 	*blkno = dumplo64 + pinfo.media_offset / pinfo.media_blksize;
234 	*secsize = pinfo.media_blksize;
235 	return (0);
236 }
237 
238 void
239 disk_invalidate (struct disk *disk)
240 {
241 	if (disk->d_slice)
242 		dsgone(&disk->d_slice);
243 }
244 
245 struct disk *
246 disk_enumerate(struct disk *disk)
247 {
248 	if (!disk)
249 		return (LIST_FIRST(&disklist));
250 	else
251 		return (LIST_NEXT(disk, d_list));
252 }
253 
254 static
255 int
256 sysctl_disks(SYSCTL_HANDLER_ARGS)
257 {
258 	struct disk *disk;
259 	int error, first;
260 
261 	disk = NULL;
262 	first = 1;
263 
264 	while ((disk = disk_enumerate(disk))) {
265 		if (!first) {
266 			error = SYSCTL_OUT(req, " ", 1);
267 			if (error)
268 				return error;
269 		} else {
270 			first = 0;
271 		}
272 		error = SYSCTL_OUT(req, disk->d_rawdev->si_name,
273 				   strlen(disk->d_rawdev->si_name));
274 		if (error)
275 			return error;
276 	}
277 	error = SYSCTL_OUT(req, "", 1);
278 	return error;
279 }
280 
281 SYSCTL_PROC(_kern, OID_AUTO, disks, CTLTYPE_STRING | CTLFLAG_RD, 0, NULL,
282     sysctl_disks, "A", "names of available disks");
283 
284 /*
285  * Open a disk device or partition.
286  */
287 static
288 int
289 diskopen(struct dev_open_args *ap)
290 {
291 	cdev_t dev = ap->a_head.a_dev;
292 	struct disk *dp;
293 	int error;
294 
295 	/*
296 	 * dp can't be NULL here XXX.
297 	 */
298 	dp = dev->si_disk;
299 	if (dp == NULL)
300 		return (ENXIO);
301 	error = 0;
302 
303 	/*
304 	 * Deal with open races
305 	 */
306 	while (dp->d_flags & DISKFLAG_LOCK) {
307 		dp->d_flags |= DISKFLAG_WANTED;
308 		error = tsleep(dp, PCATCH, "diskopen", hz);
309 		if (error)
310 			return (error);
311 	}
312 	dp->d_flags |= DISKFLAG_LOCK;
313 
314 	/*
315 	 * Open the underlying raw device.
316 	 */
317 	if (!dsisopen(dp->d_slice)) {
318 #if 0
319 		if (!pdev->si_iosize_max)
320 			pdev->si_iosize_max = dev->si_iosize_max;
321 #endif
322 		error = dev_dopen(dp->d_rawdev, ap->a_oflags,
323 				  ap->a_devtype, ap->a_cred);
324 	}
325 
326 	/*
327 	 * Inherit properties from the underlying device now that it is
328 	 * open.
329 	 */
330 	dev_dclone(dev);
331 
332 	if (error)
333 		goto out;
334 
335 	error = dsopen(dev, ap->a_devtype, dp->d_info.d_dsflags,
336 		       &dp->d_slice, &dp->d_info);
337 
338 	if (!dsisopen(dp->d_slice))
339 		dev_dclose(dp->d_rawdev, ap->a_oflags, ap->a_devtype);
340 out:
341 	dp->d_flags &= ~DISKFLAG_LOCK;
342 	if (dp->d_flags & DISKFLAG_WANTED) {
343 		dp->d_flags &= ~DISKFLAG_WANTED;
344 		wakeup(dp);
345 	}
346 
347 	return(error);
348 }
349 
350 /*
351  * Close a disk device or partition
352  */
353 static
354 int
355 diskclose(struct dev_close_args *ap)
356 {
357 	cdev_t dev = ap->a_head.a_dev;
358 	struct disk *dp;
359 	int error;
360 
361 	error = 0;
362 	dp = dev->si_disk;
363 
364 	dsclose(dev, ap->a_devtype, dp->d_slice);
365 	if (!dsisopen(dp->d_slice))
366 		error = dev_dclose(dp->d_rawdev, ap->a_fflag, ap->a_devtype);
367 	return (error);
368 }
369 
370 /*
371  * First execute the ioctl on the disk device, and if it isn't supported
372  * try running it on the backing device.
373  */
374 static
375 int
376 diskioctl(struct dev_ioctl_args *ap)
377 {
378 	cdev_t dev = ap->a_head.a_dev;
379 	struct disk *dp;
380 	int error;
381 
382 	dp = dev->si_disk;
383 	if (dp == NULL)
384 		return (ENXIO);
385 	error = dsioctl(dev, ap->a_cmd, ap->a_data, ap->a_fflag,
386 			&dp->d_slice, &dp->d_info);
387 	if (error == ENOIOCTL) {
388 		error = dev_dioctl(dp->d_rawdev, ap->a_cmd, ap->a_data,
389 				   ap->a_fflag, ap->a_cred);
390 	}
391 	return (error);
392 }
393 
394 /*
395  * Execute strategy routine
396  */
397 static
398 int
399 diskstrategy(struct dev_strategy_args *ap)
400 {
401 	cdev_t dev = ap->a_head.a_dev;
402 	struct bio *bio = ap->a_bio;
403 	struct bio *nbio;
404 	struct disk *dp;
405 
406 	dp = dev->si_disk;
407 
408 	if (dp == NULL) {
409 		bio->bio_buf->b_error = ENXIO;
410 		bio->bio_buf->b_flags |= B_ERROR;
411 		biodone(bio);
412 		return(0);
413 	}
414 	KKASSERT(dev->si_disk == dp);
415 
416 	/*
417 	 * The dscheck() function will also transform the slice relative
418 	 * block number i.e. bio->bio_offset into a block number that can be
419 	 * passed directly to the underlying raw device.  If dscheck()
420 	 * returns NULL it will have handled the bio for us (e.g. EOF
421 	 * or error due to being beyond the device size).
422 	 */
423 	if ((nbio = dscheck(dev, bio, dp->d_slice)) != NULL)
424 		dev_dstrategy(dp->d_rawdev, nbio);
425 	else
426 		biodone(bio);
427 	return(0);
428 }
429 
430 /*
431  * Return the partition size in ?blocks?
432  */
433 static
434 int
435 diskpsize(struct dev_psize_args *ap)
436 {
437 	cdev_t dev = ap->a_head.a_dev;
438 	struct disk *dp;
439 
440 	dp = dev->si_disk;
441 	if (dp == NULL)
442 		return(ENODEV);
443 	ap->a_result = dssize(dev, &dp->d_slice);
444 	return(0);
445 }
446 
447 /*
448  * When new device entries are instantiated, make sure they inherit our
449  * si_disk structure and block and iosize limits from the raw device.
450  *
451  * This routine is always called synchronously in the context of the
452  * client.
453  *
454  * XXX The various io and block size constraints are not always initialized
455  * properly by devices.
456  */
457 static
458 int
459 diskclone(struct dev_clone_args *ap)
460 {
461 	cdev_t dev = ap->a_head.a_dev;
462 	struct disk *dp;
463 
464 	dp = dev->si_ops->head.data;
465 	KKASSERT(dp != NULL);
466 	dev->si_disk = dp;
467 	dev->si_iosize_max = dp->d_rawdev->si_iosize_max;
468 	dev->si_bsize_phys = dp->d_rawdev->si_bsize_phys;
469 	dev->si_bsize_best = dp->d_rawdev->si_bsize_best;
470 	return(0);
471 }
472 
473 int
474 diskdump(struct dev_dump_args *ap)
475 {
476 	cdev_t dev = ap->a_head.a_dev;
477 	struct disk *dp = dev->si_ops->head.data;
478 	int error;
479 
480 	error = disk_dumpcheck(dev, &ap->a_count, &ap->a_blkno, &ap->a_secsize);
481 	if (error == 0) {
482 		ap->a_head.a_dev = dp->d_rawdev;
483 		error = dev_doperate(&ap->a_head);
484 	}
485 
486 	return(error);
487 }
488 
489 
490 SYSCTL_INT(_debug_sizeof, OID_AUTO, diskslices, CTLFLAG_RD,
491     0, sizeof(struct diskslices), "sizeof(struct diskslices)");
492 
493 SYSCTL_INT(_debug_sizeof, OID_AUTO, disk, CTLFLAG_RD,
494     0, sizeof(struct disk), "sizeof(struct disk)");
495 
496 
497 /*
498  * Seek sort for disks.
499  *
500  * The bio_queue keep two queues, sorted in ascending block order.  The first
501  * queue holds those requests which are positioned after the current block
502  * (in the first request); the second, which starts at queue->switch_point,
503  * holds requests which came in after their block number was passed.  Thus
504  * we implement a one way scan, retracting after reaching the end of the drive
505  * to the first request on the second queue, at which time it becomes the
506  * first queue.
507  *
508  * A one-way scan is natural because of the way UNIX read-ahead blocks are
509  * allocated.
510  */
511 void
512 bioqdisksort(struct bio_queue_head *bioq, struct bio *bio)
513 {
514 	struct bio *bq;
515 	struct bio *bn;
516 	struct bio *be;
517 
518 	be = TAILQ_LAST(&bioq->queue, bio_queue);
519 	/*
520 	 * If the queue is empty or we are an
521 	 * ordered transaction, then it's easy.
522 	 */
523 	if ((bq = bioq_first(bioq)) == NULL ||
524 	    (bio->bio_buf->b_flags & B_ORDERED) != 0) {
525 		bioq_insert_tail(bioq, bio);
526 		return;
527 	} else if (bioq->insert_point != NULL) {
528 
529 		/*
530 		 * A certain portion of the list is
531 		 * "locked" to preserve ordering, so
532 		 * we can only insert after the insert
533 		 * point.
534 		 */
535 		bq = bioq->insert_point;
536 	} else {
537 
538 		/*
539 		 * If we lie before the last removed (currently active)
540 		 * request, and are not inserting ourselves into the
541 		 * "locked" portion of the list, then we must add ourselves
542 		 * to the second request list.
543 		 */
544 		if (bio->bio_offset < bioq->last_offset) {
545 			bq = bioq->switch_point;
546 			/*
547 			 * If we are starting a new secondary list,
548 			 * then it's easy.
549 			 */
550 			if (bq == NULL) {
551 				bioq->switch_point = bio;
552 				bioq_insert_tail(bioq, bio);
553 				return;
554 			}
555 			/*
556 			 * If we lie ahead of the current switch point,
557 			 * insert us before the switch point and move
558 			 * the switch point.
559 			 */
560 			if (bio->bio_offset < bq->bio_offset) {
561 				bioq->switch_point = bio;
562 				TAILQ_INSERT_BEFORE(bq, bio, bio_act);
563 				return;
564 			}
565 		} else {
566 			if (bioq->switch_point != NULL)
567 				be = TAILQ_PREV(bioq->switch_point,
568 						bio_queue, bio_act);
569 			/*
570 			 * If we lie between last_offset and bq,
571 			 * insert before bq.
572 			 */
573 			if (bio->bio_offset < bq->bio_offset) {
574 				TAILQ_INSERT_BEFORE(bq, bio, bio_act);
575 				return;
576 			}
577 		}
578 	}
579 
580 	/*
581 	 * Request is at/after our current position in the list.
582 	 * Optimize for sequential I/O by seeing if we go at the tail.
583 	 */
584 	if (bio->bio_offset > be->bio_offset) {
585 		TAILQ_INSERT_AFTER(&bioq->queue, be, bio, bio_act);
586 		return;
587 	}
588 
589 	/* Otherwise, insertion sort */
590 	while ((bn = TAILQ_NEXT(bq, bio_act)) != NULL) {
591 
592 		/*
593 		 * We want to go after the current request if it is the end
594 		 * of the first request list, or if the next request is a
595 		 * larger cylinder than our request.
596 		 */
597 		if (bn == bioq->switch_point
598 		 || bio->bio_offset < bn->bio_offset)
599 			break;
600 		bq = bn;
601 	}
602 	TAILQ_INSERT_AFTER(&bioq->queue, bq, bio, bio_act);
603 }
604 
605 
606 /*
607  * Attempt to read a disk label from a device using the indicated strategy
608  * routine.  The label must be partly set up before this: secpercyl, secsize
609  * and anything required in the strategy routine (e.g., dummy bounds for the
610  * partition containing the label) must be filled in before calling us.
611  * Returns NULL on success and an error string on failure.
612  */
613 char *
614 readdisklabel(cdev_t dev, struct disklabel *lp)
615 {
616 	struct buf *bp;
617 	struct disklabel *dlp;
618 	char *msg = NULL;
619 
620 	bp = geteblk((int)lp->d_secsize);
621 	bp->b_bio1.bio_offset = (off_t)LABELSECTOR * lp->d_secsize;
622 	bp->b_bcount = lp->d_secsize;
623 	bp->b_flags &= ~B_INVAL;
624 	bp->b_cmd = BUF_CMD_READ;
625 	dev_dstrategy(dev, &bp->b_bio1);
626 	if (biowait(bp))
627 		msg = "I/O error";
628 	else for (dlp = (struct disklabel *)bp->b_data;
629 	    dlp <= (struct disklabel *)((char *)bp->b_data +
630 	    lp->d_secsize - sizeof(*dlp));
631 	    dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
632 		if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) {
633 			if (msg == NULL)
634 				msg = "no disk label";
635 		} else if (dlp->d_npartitions > MAXPARTITIONS ||
636 			   dkcksum(dlp) != 0)
637 			msg = "disk label corrupted";
638 		else {
639 			*lp = *dlp;
640 			msg = NULL;
641 			break;
642 		}
643 	}
644 	bp->b_flags |= B_INVAL | B_AGE;
645 	brelse(bp);
646 	return (msg);
647 }
648 
649 /*
650  * Check new disk label for sensibility before setting it.
651  */
652 int
653 setdisklabel(struct disklabel *olp, struct disklabel *nlp, u_long openmask)
654 {
655 	int i;
656 	struct partition *opp, *npp;
657 
658 	/*
659 	 * Check it is actually a disklabel we are looking at.
660 	 */
661 	if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC ||
662 	    dkcksum(nlp) != 0)
663 		return (EINVAL);
664 	/*
665 	 * For each partition that we think is open,
666 	 */
667 	while ((i = ffs((long)openmask)) != 0) {
668 		i--;
669 		/*
670 	 	 * Check it is not changing....
671 	 	 */
672 		openmask &= ~(1 << i);
673 		if (nlp->d_npartitions <= i)
674 			return (EBUSY);
675 		opp = &olp->d_partitions[i];
676 		npp = &nlp->d_partitions[i];
677 		if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size)
678 			return (EBUSY);
679 		/*
680 		 * Copy internally-set partition information
681 		 * if new label doesn't include it.		XXX
682 		 * (If we are using it then we had better stay the same type)
683 		 * This is possibly dubious, as someone else noted (XXX)
684 		 */
685 		if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) {
686 			npp->p_fstype = opp->p_fstype;
687 			npp->p_fsize = opp->p_fsize;
688 			npp->p_frag = opp->p_frag;
689 			npp->p_cpg = opp->p_cpg;
690 		}
691 	}
692  	nlp->d_checksum = 0;
693  	nlp->d_checksum = dkcksum(nlp);
694 	*olp = *nlp;
695 	return (0);
696 }
697 
698 /*
699  * Write disk label back to device after modification.
700  */
701 int
702 writedisklabel(cdev_t dev, struct disklabel *lp)
703 {
704 	struct buf *bp;
705 	struct disklabel *dlp;
706 	int error = 0;
707 
708 	if (lp->d_partitions[RAW_PART].p_offset != 0)
709 		return (EXDEV);			/* not quite right */
710 	bp = geteblk((int)lp->d_secsize);
711 	bp->b_bio1.bio_offset = (off_t)LABELSECTOR * lp->d_secsize;
712 	bp->b_bcount = lp->d_secsize;
713 #if 1
714 	/*
715 	 * We read the label first to see if it's there,
716 	 * in which case we will put ours at the same offset into the block..
717 	 * (I think this is stupid [Julian])
718 	 * Note that you can't write a label out over a corrupted label!
719 	 * (also stupid.. how do you write the first one? by raw writes?)
720 	 */
721 	bp->b_flags &= ~B_INVAL;
722 	bp->b_cmd = BUF_CMD_READ;
723 	dev_dstrategy(dkmodpart(dev, WHOLE_SLICE_PART), &bp->b_bio1);
724 	error = biowait(bp);
725 	if (error)
726 		goto done;
727 	for (dlp = (struct disklabel *)bp->b_data;
728 	    dlp <= (struct disklabel *)
729 	      ((char *)bp->b_data + lp->d_secsize - sizeof(*dlp));
730 	    dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
731 		if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC &&
732 		    dkcksum(dlp) == 0) {
733 			*dlp = *lp;
734 			bp->b_cmd = BUF_CMD_WRITE;
735 			dev_dstrategy(dkmodpart(dev, WHOLE_SLICE_PART), &bp->b_bio1);
736 			error = biowait(bp);
737 			goto done;
738 		}
739 	}
740 	error = ESRCH;
741 done:
742 #else
743 	bzero(bp->b_data, lp->d_secsize);
744 	dlp = (struct disklabel *)bp->b_data;
745 	*dlp = *lp;
746 	bp->b_flags &= ~B_INVAL;
747 	bp->b_cmd = BUF_CMD_WRITE;
748 	BUF_STRATEGY(bp, 1);
749 	error = biowait(bp);
750 #endif
751 	bp->b_flags |= B_INVAL | B_AGE;
752 	brelse(bp);
753 	return (error);
754 }
755 
756 /*
757  * Disk error is the preface to plaintive error messages
758  * about failing disk transfers.  It prints messages of the form
759 
760 hp0g: hard error reading fsbn 12345 of 12344-12347 (hp0 bn %d cn %d tn %d sn %d)
761 
762  * if the offset of the error in the transfer and a disk label
763  * are both available.  blkdone should be -1 if the position of the error
764  * is unknown; the disklabel pointer may be null from drivers that have not
765  * been converted to use them.  The message is printed with kprintf
766  * if pri is LOG_PRINTF, otherwise it uses log at the specified priority.
767  * The message should be completed (with at least a newline) with kprintf
768  * or log(-1, ...), respectively.  There is no trailing space.
769  */
770 void
771 diskerr(struct bio *bio, cdev_t dev, const char *what, int pri, int donecnt)
772 {
773 	struct buf *bp = bio->bio_buf;
774 	int unit = dkunit(dev);
775 	int slice = dkslice(dev);
776 	int part = dkpart(dev);
777 	char partname[2];
778 	char *sname;
779 
780 	sname = dsname(dev, unit, slice, part, partname);
781 	kprintf("%s%s: %s %sing ", sname, partname, what,
782 	      (bp->b_cmd == BUF_CMD_READ) ? "read" : "writ");
783 	kprintf("offset %012llx for %d", bio->bio_offset, bp->b_bcount);
784 	if (donecnt)
785 		kprintf(" (%d bytes completed)", donecnt);
786 }
787 
788