xref: /openbsd-src/sys/kern/subr_disk.c (revision 850e275390052b330d93020bf619a739a3c277ac)
1 /*	$OpenBSD: subr_disk.c,v 1.82 2008/08/25 11:27:00 krw Exp $	*/
2 /*	$NetBSD: subr_disk.c,v 1.17 1996/03/16 23:17:08 christos Exp $	*/
3 
4 /*
5  * Copyright (c) 1995 Jason R. Thorpe.  All rights reserved.
6  * Copyright (c) 1982, 1986, 1988, 1993
7  *	The Regents of the University of California.  All rights reserved.
8  * (c) UNIX System Laboratories, Inc.
9  * All or some portions of this file are derived from material licensed
10  * to the University of California by American Telephone and Telegraph
11  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
12  * the permission of UNIX System Laboratories, Inc.
13  *
14  * Redistribution and use in source and binary forms, with or without
15  * modification, are permitted provided that the following conditions
16  * are met:
17  * 1. Redistributions of source code must retain the above copyright
18  *    notice, this list of conditions and the following disclaimer.
19  * 2. Redistributions in binary form must reproduce the above copyright
20  *    notice, this list of conditions and the following disclaimer in the
21  *    documentation and/or other materials provided with the distribution.
22  * 3. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)ufs_disksubr.c	8.5 (Berkeley) 1/21/94
39  */
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/kernel.h>
44 #include <sys/malloc.h>
45 #include <sys/fcntl.h>
46 #include <sys/buf.h>
47 #include <sys/stat.h>
48 #include <sys/syslog.h>
49 #include <sys/device.h>
50 #include <sys/time.h>
51 #include <sys/disklabel.h>
52 #include <sys/conf.h>
53 #include <sys/lock.h>
54 #include <sys/disk.h>
55 #include <sys/reboot.h>
56 #include <sys/dkio.h>
57 #include <sys/dkstat.h>		/* XXX */
58 #include <sys/proc.h>
59 #include <uvm/uvm_extern.h>
60 
61 #include <sys/socket.h>
62 #include <sys/socketvar.h>
63 
64 #include <net/if.h>
65 
66 #include <dev/rndvar.h>
67 #include <dev/cons.h>
68 
69 /*
70  * A global list of all disks attached to the system.  May grow or
71  * shrink over time.
72  */
73 struct	disklist_head disklist;	/* TAILQ_HEAD */
74 int	disk_count;		/* number of drives in global disklist */
75 int	disk_change;		/* set if a disk has been attached/detached
76 				 * since last we looked at this variable. This
77 				 * is reset by hw_sysctl()
78 				 */
79 
80 /*
81  * Seek sort for disks.  We depend on the driver which calls us using b_resid
82  * as the current cylinder number.
83  *
84  * The argument ap structure holds a b_actf activity chain pointer on which we
85  * keep two queues, sorted in ascending cylinder order.  The first queue holds
86  * those requests which are positioned after the current cylinder (in the first
87  * request); the second holds requests which came in after their cylinder number
88  * was passed.  Thus we implement a one way scan, retracting after reaching the
89  * end of the drive to the first request on the second queue, at which time it
90  * becomes the first queue.
91  *
92  * A one-way scan is natural because of the way UNIX read-ahead blocks are
93  * allocated.
94  */
95 
96 void
97 disksort(struct buf *ap, struct buf *bp)
98 {
99 	struct buf *bq;
100 
101 	/* If the queue is empty, then it's easy. */
102 	if (ap->b_actf == NULL) {
103 		bp->b_actf = NULL;
104 		ap->b_actf = bp;
105 		return;
106 	}
107 
108 	/*
109 	 * If we lie after the first (currently active) request, then we
110 	 * must locate the second request list and add ourselves to it.
111 	 */
112 	bq = ap->b_actf;
113 	if (bp->b_cylinder < bq->b_cylinder) {
114 		while (bq->b_actf) {
115 			/*
116 			 * Check for an ``inversion'' in the normally ascending
117 			 * cylinder numbers, indicating the start of the second
118 			 * request list.
119 			 */
120 			if (bq->b_actf->b_cylinder < bq->b_cylinder) {
121 				/*
122 				 * Search the second request list for the first
123 				 * request at a larger cylinder number.  We go
124 				 * before that; if there is no such request, we
125 				 * go at end.
126 				 */
127 				do {
128 					if (bp->b_cylinder <
129 					    bq->b_actf->b_cylinder)
130 						goto insert;
131 					if (bp->b_cylinder ==
132 					    bq->b_actf->b_cylinder &&
133 					    bp->b_blkno < bq->b_actf->b_blkno)
134 						goto insert;
135 					bq = bq->b_actf;
136 				} while (bq->b_actf);
137 				goto insert;		/* after last */
138 			}
139 			bq = bq->b_actf;
140 		}
141 		/*
142 		 * No inversions... we will go after the last, and
143 		 * be the first request in the second request list.
144 		 */
145 		goto insert;
146 	}
147 	/*
148 	 * Request is at/after the current request...
149 	 * sort in the first request list.
150 	 */
151 	while (bq->b_actf) {
152 		/*
153 		 * We want to go after the current request if there is an
154 		 * inversion after it (i.e. it is the end of the first
155 		 * request list), or if the next request is a larger cylinder
156 		 * than our request.
157 		 */
158 		if (bq->b_actf->b_cylinder < bq->b_cylinder ||
159 		    bp->b_cylinder < bq->b_actf->b_cylinder ||
160 		    (bp->b_cylinder == bq->b_actf->b_cylinder &&
161 		    bp->b_blkno < bq->b_actf->b_blkno))
162 			goto insert;
163 		bq = bq->b_actf;
164 	}
165 	/*
166 	 * Neither a second list nor a larger request... we go at the end of
167 	 * the first list, which is the same as the end of the whole schebang.
168 	 */
169 insert:	bp->b_actf = bq->b_actf;
170 	bq->b_actf = bp;
171 }
172 
173 /*
174  * Compute checksum for disk label.
175  */
176 u_int
177 dkcksum(struct disklabel *lp)
178 {
179 	u_int16_t *start, *end;
180 	u_int16_t sum = 0;
181 
182 	start = (u_int16_t *)lp;
183 	end = (u_int16_t *)&lp->d_partitions[lp->d_npartitions];
184 	while (start < end)
185 		sum ^= *start++;
186 	return (sum);
187 }
188 
189 char *
190 initdisklabel(struct disklabel *lp)
191 {
192 	int i;
193 
194 	/* minimal requirements for archetypal disk label */
195 	if (lp->d_secsize < DEV_BSIZE)
196 		lp->d_secsize = DEV_BSIZE;
197 	if (DL_GETDSIZE(lp) == 0)
198 		DL_SETDSIZE(lp, MAXDISKSIZE);
199 	if (lp->d_secpercyl == 0)
200 		return ("invalid geometry");
201 	lp->d_npartitions = RAW_PART + 1;
202 	for (i = 0; i < RAW_PART; i++) {
203 		DL_SETPSIZE(&lp->d_partitions[i], 0);
204 		DL_SETPOFFSET(&lp->d_partitions[i], 0);
205 	}
206 	if (DL_GETPSIZE(&lp->d_partitions[RAW_PART]) == 0)
207 		DL_SETPSIZE(&lp->d_partitions[RAW_PART], DL_GETDSIZE(lp));
208 	DL_SETPOFFSET(&lp->d_partitions[RAW_PART], 0);
209 	lp->d_version = 1;
210 	lp->d_bbsize = 8192;
211 	lp->d_sbsize = 64*1024;			/* XXX ? */
212 	return (NULL);
213 }
214 
215 /*
216  * Check an incoming block to make sure it is a disklabel, convert it to
217  * a newer version if needed, etc etc.
218  */
219 char *
220 checkdisklabel(void *rlp, struct disklabel *lp)
221 {
222 	struct disklabel *dlp = rlp;
223 	struct __partitionv0 *v0pp;
224 	struct partition *pp;
225 	daddr64_t disksize;
226 	char *msg = NULL;
227 	int i;
228 
229 	if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC)
230 		msg = "no disk label";
231 	else if (dlp->d_npartitions > MAXPARTITIONS)
232 		msg = "unreasonable partition count";
233 	else if (dkcksum(dlp) != 0)
234 		msg = "disk label corrupted";
235 
236 	if (msg) {
237 		u_int16_t *start, *end, sum = 0;
238 
239 		/* If it is byte-swapped, attempt to convert it */
240 		if (swap32(dlp->d_magic) != DISKMAGIC ||
241 		    swap32(dlp->d_magic2) != DISKMAGIC ||
242 		    swap16(dlp->d_npartitions) > MAXPARTITIONS)
243 			return (msg);
244 
245 		/*
246 		 * Need a byte-swap aware dkcksum varient
247 		 * inlined, because dkcksum uses a sub-field
248 		 */
249 		start = (u_int16_t *)dlp;
250 		end = (u_int16_t *)&dlp->d_partitions[
251 		    swap16(dlp->d_npartitions)];
252 		while (start < end)
253 			sum ^= *start++;
254 		if (sum != 0)
255 			return (msg);
256 
257 		dlp->d_magic = swap32(dlp->d_magic);
258 		dlp->d_type = swap16(dlp->d_type);
259 		dlp->d_subtype = swap16(dlp->d_subtype);
260 
261 		/* d_typename and d_packname are strings */
262 
263 		dlp->d_secsize = swap32(dlp->d_secsize);
264 		dlp->d_nsectors = swap32(dlp->d_nsectors);
265 		dlp->d_ntracks = swap32(dlp->d_ntracks);
266 		dlp->d_ncylinders = swap32(dlp->d_ncylinders);
267 		dlp->d_secpercyl = swap32(dlp->d_secpercyl);
268 		dlp->d_secperunit = swap32(dlp->d_secperunit);
269 
270 		dlp->d_sparespertrack = swap16(dlp->d_sparespertrack);
271 		dlp->d_sparespercyl = swap16(dlp->d_sparespercyl);
272 
273 		dlp->d_acylinders = swap32(dlp->d_acylinders);
274 
275 		dlp->d_rpm = swap16(dlp->d_rpm);
276 		dlp->d_interleave = swap16(dlp->d_interleave);
277 		dlp->d_trackskew = swap16(dlp->d_trackskew);
278 		dlp->d_cylskew = swap16(dlp->d_cylskew);
279 		dlp->d_headswitch = swap32(dlp->d_headswitch);
280 		dlp->d_trkseek = swap32(dlp->d_trkseek);
281 		dlp->d_flags = swap32(dlp->d_flags);
282 
283 		for (i = 0; i < NDDATA; i++)
284 			dlp->d_drivedata[i] = swap32(dlp->d_drivedata[i]);
285 
286 		dlp->d_secperunith = swap16(dlp->d_secperunith);
287 		dlp->d_version = swap16(dlp->d_version);
288 
289 		for (i = 0; i < NSPARE; i++)
290 			dlp->d_spare[i] = swap32(dlp->d_spare[i]);
291 
292 		dlp->d_magic2 = swap32(dlp->d_magic2);
293 		dlp->d_checksum = swap16(dlp->d_checksum);
294 
295 		dlp->d_npartitions = swap16(dlp->d_npartitions);
296 		dlp->d_bbsize = swap32(dlp->d_bbsize);
297 		dlp->d_sbsize = swap32(dlp->d_sbsize);
298 
299 		for (i = 0; i < MAXPARTITIONS; i++) {
300 			pp = &dlp->d_partitions[i];
301 			pp->p_size = swap32(pp->p_size);
302 			pp->p_offset = swap32(pp->p_offset);
303 			if (dlp->d_version == 0) {
304 				v0pp = (struct __partitionv0 *)pp;
305 				v0pp->p_fsize = swap32(v0pp->p_fsize);
306 			} else {
307 				pp->p_offseth = swap16(pp->p_offseth);
308 				pp->p_sizeh = swap16(pp->p_sizeh);
309 			}
310 			pp->p_cpg = swap16(pp->p_cpg);
311 		}
312 
313 		dlp->d_checksum = 0;
314 		dlp->d_checksum = dkcksum(dlp);
315 		msg = NULL;
316 	}
317 
318 	/* XXX should verify lots of other fields and whine a lot */
319 
320 	if (msg)
321 		return (msg);
322 
323 	/* Initial passed in lp contains the real disk size. */
324 	disksize = DL_GETDSIZE(lp);
325 
326 	if (lp != dlp)
327 		*lp = *dlp;
328 
329 	if (lp->d_version == 0) {
330 		lp->d_version = 1;
331 		lp->d_secperunith = 0;
332 
333 		v0pp = (struct __partitionv0 *)lp->d_partitions;
334 		pp = lp->d_partitions;
335 		for (i = 0; i < lp->d_npartitions; i++, pp++, v0pp++) {
336 			pp->p_fragblock = DISKLABELV1_FFS_FRAGBLOCK(v0pp->
337 			    p_fsize, v0pp->p_frag);
338 			pp->p_offseth = 0;
339 			pp->p_sizeh = 0;
340 		}
341 	}
342 
343 #ifdef DEBUG
344 	if (DL_GETDSIZE(lp) != disksize)
345 		printf("on-disk disklabel has incorrect disksize (%lld)\n",
346 		    DL_GETDSIZE(lp));
347 	if (DL_GETPSIZE(&lp->d_partitions[RAW_PART]) != disksize)
348 		printf("on-disk disklabel RAW_PART has incorrect size (%lld)\n",
349 		    DL_GETPSIZE(&lp->d_partitions[RAW_PART]));
350 	if (DL_GETPOFFSET(&lp->d_partitions[RAW_PART]) != 0)
351 		printf("on-disk disklabel RAW_PART offset != 0 (%lld)\n",
352 		    DL_GETPOFFSET(&lp->d_partitions[RAW_PART]));
353 #endif
354 	DL_SETDSIZE(lp, disksize);
355 	DL_SETPSIZE(&lp->d_partitions[RAW_PART], disksize);
356 	DL_SETPOFFSET(&lp->d_partitions[RAW_PART], 0);
357 
358 	lp->d_checksum = 0;
359 	lp->d_checksum = dkcksum(lp);
360 	return (msg);
361 }
362 
363 /*
364  * If dos partition table requested, attempt to load it and
365  * find disklabel inside a DOS partition. Return buffer
366  * for use in signalling errors if requested.
367  *
368  * We would like to check if each MBR has a valid BOOT_MAGIC, but
369  * we cannot because it doesn't always exist. So.. we assume the
370  * MBR is valid.
371  */
372 char *
373 readdoslabel(struct buf *bp, void (*strat)(struct buf *),
374     struct disklabel *lp, int *partoffp, int spoofonly)
375 {
376 	struct dos_partition dp[NDOSPART], *dp2;
377 	u_int32_t extoff = 0;
378 	daddr64_t part_blkno = DOSBBSECTOR;
379 	int dospartoff = 0, i, ourpart = -1;
380 	int wander = 1, n = 0, loop = 0;
381 	int offset;
382 
383 	if (lp->d_secpercyl == 0)
384 		return ("invalid label, d_secpercyl == 0");
385 	if (lp->d_secsize == 0)
386 		return ("invalid label, d_secsize == 0");
387 
388 	/* do DOS partitions in the process of getting disklabel? */
389 
390 	/*
391 	 * Read dos partition table, follow extended partitions.
392 	 * Map the partitions to disklabel entries i-p
393 	 */
394 	while (wander && n < 8 && loop < 8) {
395 		loop++;
396 		wander = 0;
397 		if (part_blkno < extoff)
398 			part_blkno = extoff;
399 
400 		/* read boot record */
401 		bp->b_blkno = DL_BLKTOSEC(lp, part_blkno) * DL_BLKSPERSEC(lp);
402 		offset = DL_BLKOFFSET(lp, part_blkno) + DOSPARTOFF;
403 		bp->b_bcount = lp->d_secsize;
404 		bp->b_flags = B_BUSY | B_READ | B_RAW;
405 		(*strat)(bp);
406 		if (biowait(bp)) {
407 /*wrong*/		if (partoffp)
408 /*wrong*/			*partoffp = -1;
409 			return ("dos partition I/O error");
410 		}
411 
412 		bcopy(bp->b_data + offset, dp, sizeof(dp));
413 
414 		if (ourpart == -1) {
415 			/* Search for our MBR partition */
416 			for (dp2=dp, i=0; i < NDOSPART && ourpart == -1;
417 			    i++, dp2++)
418 				if (letoh32(dp2->dp_size) &&
419 				    dp2->dp_typ == DOSPTYP_OPENBSD)
420 					ourpart = i;
421 			if (ourpart == -1)
422 				goto donot;
423 			/*
424 			 * This is our MBR partition. need sector
425 			 * address for SCSI/IDE, cylinder for
426 			 * ESDI/ST506/RLL
427 			 */
428 			dp2 = &dp[ourpart];
429 			dospartoff = letoh32(dp2->dp_start) + part_blkno;
430 
431 			/* found our OpenBSD partition, finish up */
432 			if (partoffp)
433 				goto notfat;
434 
435 			if (lp->d_ntracks == 0)
436 				lp->d_ntracks = dp2->dp_ehd + 1;
437 			if (lp->d_nsectors == 0)
438 				lp->d_nsectors = DPSECT(dp2->dp_esect);
439 			if (lp->d_secpercyl == 0)
440 				lp->d_secpercyl = lp->d_ntracks *
441 				    lp->d_nsectors;
442 		}
443 donot:
444 		/*
445 		 * In case the disklabel read below fails, we want to
446 		 * provide a fake label in i-p.
447 		 */
448 		for (dp2=dp, i=0; i < NDOSPART && n < 8; i++, dp2++) {
449 			struct partition *pp = &lp->d_partitions[8+n];
450 			u_int8_t fstype;
451 
452 			if (dp2->dp_typ == DOSPTYP_OPENBSD)
453 				continue;
454 			if (letoh32(dp2->dp_size) > DL_GETDSIZE(lp))
455 				continue;
456 			if (letoh32(dp2->dp_start) > DL_GETDSIZE(lp))
457 				continue;
458 			if (letoh32(dp2->dp_size) == 0)
459 				continue;
460 
461 			switch (dp2->dp_typ) {
462 			case DOSPTYP_UNUSED:
463 				fstype = FS_UNUSED;
464 				n++;
465 				break;
466 
467 			case DOSPTYP_LINUX:
468 				fstype = FS_EXT2FS;
469 				n++;
470 				break;
471 
472 			case DOSPTYP_NTFS:
473 				fstype = FS_NTFS;
474 				n++;
475 				break;
476 
477 			case DOSPTYP_FAT12:
478 			case DOSPTYP_FAT16S:
479 			case DOSPTYP_FAT16B:
480 			case DOSPTYP_FAT16L:
481 			case DOSPTYP_FAT32:
482 			case DOSPTYP_FAT32L:
483 				fstype = FS_MSDOS;
484 				n++;
485 				break;
486 			case DOSPTYP_EXTEND:
487 			case DOSPTYP_EXTENDL:
488 				part_blkno = letoh32(dp2->dp_start) + extoff;
489 				if (!extoff) {
490 					extoff = letoh32(dp2->dp_start);
491 					part_blkno = 0;
492 				}
493 				wander = 1;
494 				break;
495 			default:
496 				fstype = FS_OTHER;
497 				n++;
498 				break;
499 			}
500 
501 			/*
502 			 * Don't set fstype/offset/size when wandering or just
503 			 * looking for the offset of the OpenBSD partition. It
504 			 * would invalidate the disklabel checksum!
505 			 */
506 			if (wander || partoffp)
507 				continue;
508 
509 			pp->p_fstype = fstype;
510 			if (letoh32(dp2->dp_start))
511 				DL_SETPOFFSET(pp,
512 				    letoh32(dp2->dp_start) + part_blkno);
513 			DL_SETPSIZE(pp, letoh32(dp2->dp_size));
514 		}
515 	}
516 	if (partoffp)
517 		/* dospartoff has been set and we must not modify *lp. */
518 		goto notfat;
519 
520 	lp->d_npartitions = MAXPARTITIONS;
521 
522 	if (n == 0 && part_blkno == DOSBBSECTOR) {
523 		u_int16_t fattest;
524 
525 		/* Check for a short jump instruction. */
526 		fattest = ((bp->b_data[0] << 8) & 0xff00) |
527 		    (bp->b_data[2] & 0xff);
528 		if (fattest != 0xeb90 && fattest != 0xe900)
529 			goto notfat;
530 
531 		/* Check for a valid bytes per sector value. */
532 		fattest = ((bp->b_data[12] << 8) & 0xff00) |
533 		    (bp->b_data[11] & 0xff);
534 		if (fattest < 512 || fattest > 4096 || (fattest % 512 != 0))
535 			goto notfat;
536 
537 		/* Check the end of sector marker. */
538 		fattest = ((bp->b_data[510] << 8) & 0xff00) |
539 		    (bp->b_data[511] & 0xff);
540 		if (fattest != 0x55aa)
541 			goto notfat;
542 
543 		/* Looks like a FAT filesystem. Spoof 'i'. */
544 		DL_SETPSIZE(&lp->d_partitions['i' - 'a'],
545 		    DL_GETPSIZE(&lp->d_partitions[RAW_PART]));
546 		DL_SETPOFFSET(&lp->d_partitions['i' - 'a'], 0);
547 		lp->d_partitions['i' - 'a'].p_fstype = FS_MSDOS;
548 	}
549 notfat:
550 
551 	/* record the OpenBSD partition's placement for the caller */
552 	if (partoffp)
553 		*partoffp = dospartoff;
554 
555 	/* don't read the on-disk label if we are in spoofed-only mode */
556 	if (spoofonly)
557 		return (NULL);
558 
559 	bp->b_blkno = DL_BLKTOSEC(lp, dospartoff + DOS_LABELSECTOR) *
560 	    DL_BLKSPERSEC(lp);
561 	offset = DL_BLKOFFSET(lp, dospartoff + DOS_LABELSECTOR);
562 	bp->b_bcount = lp->d_secsize;
563 	bp->b_flags = B_BUSY | B_READ | B_RAW;
564 	(*strat)(bp);
565 	if (biowait(bp))
566 		return ("disk label I/O error");
567 
568 	/* sub-MBR disklabels are always at a LABELOFFSET of 0 */
569 	return checkdisklabel(bp->b_data + offset, lp);
570 }
571 
572 /*
573  * Check new disk label for sensibility
574  * before setting it.
575  */
576 int
577 setdisklabel(struct disklabel *olp, struct disklabel *nlp, u_int openmask)
578 {
579 	int i;
580 	struct partition *opp, *npp;
581 
582 	/* sanity clause */
583 	if (nlp->d_secpercyl == 0 || nlp->d_secsize == 0 ||
584 	    (nlp->d_secsize % DEV_BSIZE) != 0)
585 		return (EINVAL);
586 
587 	/* special case to allow disklabel to be invalidated */
588 	if (nlp->d_magic == 0xffffffff) {
589 		*olp = *nlp;
590 		return (0);
591 	}
592 
593 	if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC ||
594 	    dkcksum(nlp) != 0)
595 		return (EINVAL);
596 
597 	/* XXX missing check if other dos partitions will be overwritten */
598 
599 	while (openmask != 0) {
600 		i = ffs(openmask) - 1;
601 		openmask &= ~(1 << i);
602 		if (nlp->d_npartitions <= i)
603 			return (EBUSY);
604 		opp = &olp->d_partitions[i];
605 		npp = &nlp->d_partitions[i];
606 		if (DL_GETPOFFSET(npp) != DL_GETPOFFSET(opp) ||
607 		    DL_GETPSIZE(npp) < DL_GETPSIZE(opp))
608 			return (EBUSY);
609 		/*
610 		 * Copy internally-set partition information
611 		 * if new label doesn't include it.		XXX
612 		 */
613 		if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) {
614 			npp->p_fstype = opp->p_fstype;
615 			npp->p_fragblock = opp->p_fragblock;
616 			npp->p_cpg = opp->p_cpg;
617 		}
618 	}
619 	nlp->d_checksum = 0;
620 	nlp->d_checksum = dkcksum(nlp);
621 	*olp = *nlp;
622 	return (0);
623 }
624 
625 /*
626  * Determine the size of the transfer, and make sure it is within the
627  * boundaries of the partition. Adjust transfer if needed, and signal errors or
628  * early completion.
629  */
630 int
631 bounds_check_with_label(struct buf *bp, struct disklabel *lp, int wlabel)
632 {
633 	struct partition *p = &lp->d_partitions[DISKPART(bp->b_dev)];
634 	daddr64_t sz = howmany(bp->b_bcount, DEV_BSIZE);
635 
636 	/* avoid division by zero */
637 	if (lp->d_secpercyl == 0)
638 		goto bad;
639 
640 	if (bp->b_blkno < 0 || sz < 0)
641 		panic("bounds_check_with_label %lld %lld\n", bp->b_blkno, sz);
642 
643 	/* beyond partition? */
644 	if (bp->b_blkno + sz > DL_SECTOBLK(lp, DL_GETPSIZE(p))) {
645 		sz = DL_SECTOBLK(lp, DL_GETPSIZE(p)) - bp->b_blkno;
646 		if (sz == 0) {
647 			/* If exactly at end of disk, return EOF. */
648 			bp->b_resid = bp->b_bcount;
649 			return (-1);
650 		}
651 		if (sz < 0)
652 			/* If past end of disk, return EINVAL. */
653 			goto bad;
654 
655 		/* Otherwise, truncate request. */
656 		bp->b_bcount = sz << DEV_BSHIFT;
657 	}
658 
659 	/* calculate cylinder for disksort to order transfers with */
660 	bp->b_cylinder = (bp->b_blkno + DL_SECTOBLK(lp, DL_GETPOFFSET(p))) /
661 	    DL_SECTOBLK(lp, lp->d_secpercyl);
662 	return (1);
663 
664 bad:
665 	bp->b_error = EINVAL;
666 	bp->b_flags |= B_ERROR;
667 	return (-1);
668 }
669 
670 /*
671  * Disk error is the preface to plaintive error messages
672  * about failing disk transfers.  It prints messages of the form
673 
674 hp0g: hard error reading fsbn 12345 of 12344-12347 (hp0 bn %d cn %d tn %d sn %d)
675 
676  * if the offset of the error in the transfer and a disk label
677  * are both available.  blkdone should be -1 if the position of the error
678  * is unknown; the disklabel pointer may be null from drivers that have not
679  * been converted to use them.  The message is printed with printf
680  * if pri is LOG_PRINTF, otherwise it uses log at the specified priority.
681  * The message should be completed (with at least a newline) with printf
682  * or addlog, respectively.  There is no trailing space.
683  */
684 void
685 diskerr(struct buf *bp, char *dname, char *what, int pri, int blkdone,
686     struct disklabel *lp)
687 {
688 	int unit = DISKUNIT(bp->b_dev), part = DISKPART(bp->b_dev);
689 	int (*pr)(const char *, ...);
690 	char partname = 'a' + part;
691 	daddr64_t sn;
692 
693 	if (pri != LOG_PRINTF) {
694 		static const char fmt[] = "";
695 		log(pri, fmt);
696 		pr = addlog;
697 	} else
698 		pr = printf;
699 	(*pr)("%s%d%c: %s %sing fsbn ", dname, unit, partname, what,
700 	    bp->b_flags & B_READ ? "read" : "writ");
701 	sn = bp->b_blkno;
702 	if (bp->b_bcount <= DEV_BSIZE)
703 		(*pr)("%lld", sn);
704 	else {
705 		if (blkdone >= 0) {
706 			sn += blkdone;
707 			(*pr)("%lld of ", sn);
708 		}
709 		(*pr)("%lld-%lld", bp->b_blkno,
710 		    bp->b_blkno + (bp->b_bcount - 1) / DEV_BSIZE);
711 	}
712 	if (lp && (blkdone >= 0 || bp->b_bcount <= lp->d_secsize)) {
713 		sn += DL_GETPOFFSET(&lp->d_partitions[part]);
714 		(*pr)(" (%s%d bn %lld; cn %lld", dname, unit, sn,
715 		    sn / lp->d_secpercyl);
716 		sn %= lp->d_secpercyl;
717 		(*pr)(" tn %lld sn %lld)", sn / lp->d_nsectors,
718 		    sn % lp->d_nsectors);
719 	}
720 }
721 
722 /*
723  * Initialize the disklist.  Called by main() before autoconfiguration.
724  */
725 void
726 disk_init(void)
727 {
728 
729 	TAILQ_INIT(&disklist);
730 	disk_count = disk_change = 0;
731 }
732 
733 int
734 disk_construct(struct disk *diskp, char *lockname)
735 {
736 	rw_init(&diskp->dk_lock, lockname);
737 	mtx_init(&diskp->dk_mtx, IPL_BIO);
738 
739 	diskp->dk_flags |= DKF_CONSTRUCTED;
740 
741 	return (0);
742 }
743 
744 /*
745  * Attach a disk.
746  */
747 void
748 disk_attach(struct disk *diskp)
749 {
750 
751 	if (!ISSET(diskp->dk_flags, DKF_CONSTRUCTED))
752 		disk_construct(diskp, diskp->dk_name);
753 
754 	/*
755 	 * Allocate and initialize the disklabel structures.  Note that
756 	 * it's not safe to sleep here, since we're probably going to be
757 	 * called during autoconfiguration.
758 	 */
759 	diskp->dk_label = malloc(sizeof(struct disklabel), M_DEVBUF,
760 	    M_NOWAIT|M_ZERO);
761 	if (diskp->dk_label == NULL)
762 		panic("disk_attach: can't allocate storage for disklabel");
763 
764 	/*
765 	 * Set the attached timestamp.
766 	 */
767 	microuptime(&diskp->dk_attachtime);
768 
769 	/*
770 	 * Link into the disklist.
771 	 */
772 	TAILQ_INSERT_TAIL(&disklist, diskp, dk_link);
773 	++disk_count;
774 	disk_change = 1;
775 }
776 
777 /*
778  * Detach a disk.
779  */
780 void
781 disk_detach(struct disk *diskp)
782 {
783 
784 	/*
785 	 * Free the space used by the disklabel structures.
786 	 */
787 	free(diskp->dk_label, M_DEVBUF);
788 
789 	/*
790 	 * Remove from the disklist.
791 	 */
792 	TAILQ_REMOVE(&disklist, diskp, dk_link);
793 	disk_change = 1;
794 	if (--disk_count < 0)
795 		panic("disk_detach: disk_count < 0");
796 }
797 
798 /*
799  * Increment a disk's busy counter.  If the counter is going from
800  * 0 to 1, set the timestamp.
801  */
802 void
803 disk_busy(struct disk *diskp)
804 {
805 
806 	/*
807 	 * XXX We'd like to use something as accurate as microtime(),
808 	 * but that doesn't depend on the system TOD clock.
809 	 */
810 	mtx_enter(&diskp->dk_mtx);
811 	if (diskp->dk_busy++ == 0)
812 		microuptime(&diskp->dk_timestamp);
813 	mtx_leave(&diskp->dk_mtx);
814 }
815 
816 /*
817  * Decrement a disk's busy counter, increment the byte count, total busy
818  * time, and reset the timestamp.
819  */
820 void
821 disk_unbusy(struct disk *diskp, long bcount, int read)
822 {
823 	struct timeval dv_time, diff_time;
824 
825 	mtx_enter(&diskp->dk_mtx);
826 
827 	if (diskp->dk_busy-- == 0)
828 		printf("disk_unbusy: %s: dk_busy < 0\n", diskp->dk_name);
829 
830 	microuptime(&dv_time);
831 
832 	timersub(&dv_time, &diskp->dk_timestamp, &diff_time);
833 	timeradd(&diskp->dk_time, &diff_time, &diskp->dk_time);
834 
835 	diskp->dk_timestamp = dv_time;
836 	if (bcount > 0) {
837 		if (read) {
838 			diskp->dk_rbytes += bcount;
839 			diskp->dk_rxfer++;
840 		} else {
841 			diskp->dk_wbytes += bcount;
842 			diskp->dk_wxfer++;
843 		}
844 	} else
845 		diskp->dk_seek++;
846 
847 	mtx_leave(&diskp->dk_mtx);
848 
849 	add_disk_randomness(bcount ^ diff_time.tv_usec);
850 }
851 
852 int
853 disk_lock(struct disk *dk)
854 {
855 	int error;
856 
857 	error = rw_enter(&dk->dk_lock, RW_WRITE|RW_INTR);
858 
859 	return (error);
860 }
861 
862 void
863 disk_unlock(struct disk *dk)
864 {
865 	rw_exit(&dk->dk_lock);
866 }
867 
868 int
869 dk_mountroot(void)
870 {
871 	dev_t rawdev, rrootdev;
872 	int part = DISKPART(rootdev);
873 	int (*mountrootfn)(void);
874 	struct disklabel dl;
875 	int error;
876 
877 	rrootdev = blktochr(rootdev);
878 	rawdev = MAKEDISKDEV(major(rrootdev), DISKUNIT(rootdev), RAW_PART);
879 #ifdef DEBUG
880 	printf("rootdev=0x%x rrootdev=0x%x rawdev=0x%x\n", rootdev,
881 	    rrootdev, rawdev);
882 #endif
883 
884 	/*
885 	 * open device, ioctl for the disklabel, and close it.
886 	 */
887 	error = (cdevsw[major(rrootdev)].d_open)(rawdev, FREAD,
888 	    S_IFCHR, curproc);
889 	if (error)
890 		panic("cannot open disk, 0x%x/0x%x, error %d",
891 		    rootdev, rrootdev, error);
892 	error = (cdevsw[major(rrootdev)].d_ioctl)(rawdev, DIOCGDINFO,
893 	    (caddr_t)&dl, FREAD, curproc);
894 	if (error)
895 		panic("cannot read disk label, 0x%x/0x%x, error %d",
896 		    rootdev, rrootdev, error);
897 	(void) (cdevsw[major(rrootdev)].d_close)(rawdev, FREAD,
898 	    S_IFCHR, curproc);
899 
900 	if (DL_GETPSIZE(&dl.d_partitions[part]) == 0)
901 		panic("root filesystem has size 0");
902 	switch (dl.d_partitions[part].p_fstype) {
903 #ifdef EXT2FS
904 	case FS_EXT2FS:
905 		{
906 		extern int ext2fs_mountroot(void);
907 		mountrootfn = ext2fs_mountroot;
908 		}
909 		break;
910 #endif
911 #ifdef FFS
912 	case FS_BSDFFS:
913 		{
914 		extern int ffs_mountroot(void);
915 		mountrootfn = ffs_mountroot;
916 		}
917 		break;
918 #endif
919 #ifdef CD9660
920 	case FS_ISO9660:
921 		{
922 		extern int cd9660_mountroot(void);
923 		mountrootfn = cd9660_mountroot;
924 		}
925 		break;
926 #endif
927 	default:
928 #ifdef FFS
929 		{
930 		extern int ffs_mountroot(void);
931 
932 		printf("filesystem type %d not known.. assuming ffs\n",
933 		    dl.d_partitions[part].p_fstype);
934 		mountrootfn = ffs_mountroot;
935 		}
936 #else
937 		panic("disk 0x%x/0x%x filesystem type %d not known",
938 		    rootdev, rrootdev, dl.d_partitions[part].p_fstype);
939 #endif
940 	}
941 	return (*mountrootfn)();
942 }
943 
944 struct bufq *
945 bufq_default_alloc(void)
946 {
947 	struct bufq_default *bq;
948 
949 	bq = malloc(sizeof(*bq), M_DEVBUF, M_NOWAIT|M_ZERO);
950 	if (bq == NULL)
951 		panic("bufq_default_alloc: no memory");
952 
953 	bq->bufq.bufq_free = bufq_default_free;
954 	bq->bufq.bufq_add = bufq_default_add;
955 	bq->bufq.bufq_get = bufq_default_get;
956 
957 	return ((struct bufq *)bq);
958 }
959 
960 void
961 bufq_default_free(struct bufq *bq)
962 {
963 	free(bq, M_DEVBUF);
964 }
965 
966 void
967 bufq_default_add(struct bufq *bq, struct buf *bp)
968 {
969 	struct bufq_default *bufq = (struct bufq_default *)bq;
970 	struct proc *p = bp->b_proc;
971 	struct buf *head;
972 
973 	if (p == NULL || p->p_nice < NZERO)
974 		head = &bufq->bufq_head[0];
975 	else if (p->p_nice == NZERO)
976 		head = &bufq->bufq_head[1];
977 	else
978 		head = &bufq->bufq_head[2];
979 
980 	disksort(head, bp);
981 }
982 
983 struct buf *
984 bufq_default_get(struct bufq *bq)
985 {
986 	struct bufq_default *bufq = (struct bufq_default *)bq;
987 	struct buf *bp, *head;
988 	int i;
989 
990 	for (i = 0; i < 3; i++) {
991 		head = &bufq->bufq_head[i];
992 		if ((bp = head->b_actf))
993 			break;
994 	}
995 	if (bp == NULL)
996 		return (NULL);
997 	head->b_actf = bp->b_actf;
998 	return (bp);
999 }
1000 
1001 struct device *
1002 getdisk(char *str, int len, int defpart, dev_t *devp)
1003 {
1004 	struct device *dv;
1005 
1006 	if ((dv = parsedisk(str, len, defpart, devp)) == NULL) {
1007 		printf("use one of: exit");
1008 		TAILQ_FOREACH(dv, &alldevs, dv_list) {
1009 			if (dv->dv_class == DV_DISK)
1010 				printf(" %s[a-p]", dv->dv_xname);
1011 #if defined(NFSCLIENT)
1012 			if (dv->dv_class == DV_IFNET)
1013 				printf(" %s", dv->dv_xname);
1014 #endif
1015 		}
1016 		printf("\n");
1017 	}
1018 	return (dv);
1019 }
1020 
1021 struct device *
1022 parsedisk(char *str, int len, int defpart, dev_t *devp)
1023 {
1024 	struct device *dv;
1025 	int majdev, part = defpart;
1026 	char c;
1027 
1028 	if (len == 0)
1029 		return (NULL);
1030 	c = str[len-1];
1031 	if (c >= 'a' && (c - 'a') < MAXPARTITIONS) {
1032 		part = c - 'a';
1033 		len -= 1;
1034 	}
1035 
1036 	TAILQ_FOREACH(dv, &alldevs, dv_list) {
1037 		if (dv->dv_class == DV_DISK &&
1038 		    strncmp(str, dv->dv_xname, len) == 0 &&
1039 		    dv->dv_xname[len] == '\0') {
1040 			majdev = findblkmajor(dv);
1041 			if (majdev < 0)
1042 				panic("parsedisk");
1043 			*devp = MAKEDISKDEV(majdev, dv->dv_unit, part);
1044 			break;
1045 		}
1046 #if defined(NFSCLIENT)
1047 		if (dv->dv_class == DV_IFNET &&
1048 		    strncmp(str, dv->dv_xname, len) == 0 &&
1049 		    dv->dv_xname[len] == '\0') {
1050 			*devp = NODEV;
1051 			break;
1052 		}
1053 #endif
1054 	}
1055 
1056 	return (dv);
1057 }
1058 
1059 void
1060 setroot(struct device *bootdv, int part, int exitflags)
1061 {
1062 	int majdev, unit, len, s;
1063 	struct swdevt *swp;
1064 	struct device *rootdv, *dv;
1065 	dev_t nrootdev, nswapdev = NODEV, temp = NODEV;
1066 	struct ifnet *ifp = NULL;
1067 	char buf[128];
1068 #if defined(NFSCLIENT)
1069 	extern char *nfsbootdevname;
1070 #endif
1071 
1072 	/*
1073 	 * If `swap generic' and we couldn't determine boot device,
1074 	 * ask the user.
1075 	 */
1076 	if (mountroot == NULL && bootdv == NULL)
1077 		boothowto |= RB_ASKNAME;
1078 	if (boothowto & RB_ASKNAME) {
1079 		while (1) {
1080 			printf("root device");
1081 			if (bootdv != NULL) {
1082 				printf(" (default %s", bootdv->dv_xname);
1083 				if (bootdv->dv_class == DV_DISK)
1084 					printf("%c", 'a' + part);
1085 				printf(")");
1086 			}
1087 			printf(": ");
1088 			s = splhigh();
1089 			cnpollc(TRUE);
1090 			len = getsn(buf, sizeof(buf));
1091 			cnpollc(FALSE);
1092 			splx(s);
1093 			if (strcmp(buf, "exit") == 0)
1094 				boot(exitflags);
1095 			if (len == 0 && bootdv != NULL) {
1096 				strlcpy(buf, bootdv->dv_xname, sizeof buf);
1097 				len = strlen(buf);
1098 			}
1099 			if (len > 0 && buf[len - 1] == '*') {
1100 				buf[--len] = '\0';
1101 				dv = getdisk(buf, len, part, &nrootdev);
1102 				if (dv != NULL) {
1103 					rootdv = dv;
1104 					nswapdev = nrootdev;
1105 					goto gotswap;
1106 				}
1107 			}
1108 			dv = getdisk(buf, len, part, &nrootdev);
1109 			if (dv != NULL) {
1110 				rootdv = dv;
1111 				break;
1112 			}
1113 		}
1114 
1115 		if (rootdv->dv_class == DV_IFNET)
1116 			goto gotswap;
1117 
1118 		/* try to build swap device out of new root device */
1119 		while (1) {
1120 			printf("swap device");
1121 			if (rootdv != NULL)
1122 				printf(" (default %s%s)", rootdv->dv_xname,
1123 				    rootdv->dv_class == DV_DISK ? "b" : "");
1124 			printf(": ");
1125 			s = splhigh();
1126 			cnpollc(TRUE);
1127 			len = getsn(buf, sizeof(buf));
1128 			cnpollc(FALSE);
1129 			splx(s);
1130 			if (strcmp(buf, "exit") == 0)
1131 				boot(exitflags);
1132 			if (len == 0 && rootdv != NULL) {
1133 				switch (rootdv->dv_class) {
1134 				case DV_IFNET:
1135 					nswapdev = NODEV;
1136 					break;
1137 				case DV_DISK:
1138 					nswapdev = MAKEDISKDEV(major(nrootdev),
1139 					    DISKUNIT(nrootdev), 1);
1140 					if (nswapdev == nrootdev)
1141 						continue;
1142 					break;
1143 				default:
1144 					break;
1145 				}
1146 				break;
1147 			}
1148 			dv = getdisk(buf, len, 1, &nswapdev);
1149 			if (dv) {
1150 				if (dv->dv_class == DV_IFNET)
1151 					nswapdev = NODEV;
1152 				if (nswapdev == nrootdev)
1153 					continue;
1154 				break;
1155 			}
1156 		}
1157 gotswap:
1158 		rootdev = nrootdev;
1159 		dumpdev = nswapdev;
1160 		swdevt[0].sw_dev = nswapdev;
1161 		swdevt[1].sw_dev = NODEV;
1162 #if defined(NFSCLIENT)
1163 	} else if (mountroot == nfs_mountroot) {
1164 		rootdv = bootdv;
1165 		rootdev = dumpdev = swapdev = NODEV;
1166 #endif
1167 	} else if (mountroot == NULL && rootdev == NODEV) {
1168 		/*
1169 		 * `swap generic'
1170 		 */
1171 		rootdv = bootdv;
1172 		majdev = findblkmajor(rootdv);
1173 		if (majdev >= 0) {
1174 			/*
1175 			 * Root and swap are on the disk.
1176 			 * Assume swap is on partition b.
1177 			 */
1178 			rootdev = MAKEDISKDEV(majdev, rootdv->dv_unit, part);
1179 			nswapdev = MAKEDISKDEV(majdev, rootdv->dv_unit, 1);
1180 		} else {
1181 			/*
1182 			 * Root and swap are on a net.
1183 			 */
1184 			nswapdev = NODEV;
1185 		}
1186 		dumpdev = nswapdev;
1187 		swdevt[0].sw_dev = nswapdev;
1188 		/* swdevt[1].sw_dev = NODEV; */
1189 	} else {
1190 		/* Completely pre-configured, but we want rootdv .. */
1191 		majdev = major(rootdev);
1192 		if (findblkname(majdev) == NULL)
1193 			return;
1194 		unit = DISKUNIT(rootdev);
1195 		part = DISKPART(rootdev);
1196 		snprintf(buf, sizeof buf, "%s%d%c",
1197 		    findblkname(majdev), unit, 'a' + part);
1198 		rootdv = parsedisk(buf, strlen(buf), 0, &nrootdev);
1199 		if (rootdv == NULL)
1200 			panic("root device (%s) not found", buf);
1201 	}
1202 
1203 	if (rootdv && rootdv == bootdv && rootdv->dv_class == DV_IFNET)
1204 		ifp = ifunit(rootdv->dv_xname);
1205 	else if (bootdv && bootdv->dv_class == DV_IFNET)
1206 		ifp = ifunit(bootdv->dv_xname);
1207 
1208 	if (ifp)
1209 		if_addgroup(ifp, "netboot");
1210 
1211 	switch (rootdv->dv_class) {
1212 #if defined(NFSCLIENT)
1213 	case DV_IFNET:
1214 		mountroot = nfs_mountroot;
1215 		nfsbootdevname = rootdv->dv_xname;
1216 		return;
1217 #endif
1218 	case DV_DISK:
1219 		mountroot = dk_mountroot;
1220 		part = DISKPART(rootdev);
1221 		break;
1222 	default:
1223 		printf("can't figure root, hope your kernel is right\n");
1224 		return;
1225 	}
1226 
1227 	printf("root on %s%c", rootdv->dv_xname, 'a' + part);
1228 
1229 	/*
1230 	 * Make the swap partition on the root drive the primary swap.
1231 	 */
1232 	for (swp = swdevt; swp->sw_dev != NODEV; swp++) {
1233 		if (major(rootdev) == major(swp->sw_dev) &&
1234 		    DISKUNIT(rootdev) == DISKUNIT(swp->sw_dev)) {
1235 			temp = swdevt[0].sw_dev;
1236 			swdevt[0].sw_dev = swp->sw_dev;
1237 			swp->sw_dev = temp;
1238 			break;
1239 		}
1240 	}
1241 	if (swp->sw_dev != NODEV) {
1242 		/*
1243 		 * If dumpdev was the same as the old primary swap device,
1244 		 * move it to the new primary swap device.
1245 		 */
1246 		if (temp == dumpdev)
1247 			dumpdev = swdevt[0].sw_dev;
1248 	}
1249 	if (swdevt[0].sw_dev != NODEV)
1250 		printf(" swap on %s%d%c", findblkname(major(swdevt[0].sw_dev)),
1251 		    DISKUNIT(swdevt[0].sw_dev),
1252 		    'a' + DISKPART(swdevt[0].sw_dev));
1253 	if (dumpdev != NODEV)
1254 		printf(" dump on %s%d%c", findblkname(major(dumpdev)),
1255 		    DISKUNIT(dumpdev), 'a' + DISKPART(dumpdev));
1256 	printf("\n");
1257 }
1258 
1259 extern struct nam2blk nam2blk[];
1260 
1261 int
1262 findblkmajor(struct device *dv)
1263 {
1264 	char buf[16], *p;
1265 	int i;
1266 
1267 	if (strlcpy(buf, dv->dv_xname, sizeof buf) >= sizeof buf)
1268 		return (-1);
1269 	for (p = buf; *p; p++)
1270 		if (*p >= '0' && *p <= '9')
1271 			*p = '\0';
1272 
1273 	for (i = 0; nam2blk[i].name; i++)
1274 		if (!strcmp(buf, nam2blk[i].name))
1275 			return (nam2blk[i].maj);
1276 	return (-1);
1277 }
1278 
1279 char *
1280 findblkname(int maj)
1281 {
1282 	int i;
1283 
1284 	for (i = 0; nam2blk[i].name; i++)
1285 		if (nam2blk[i].maj == maj)
1286 			return (nam2blk[i].name);
1287 	return (NULL);
1288 }
1289