xref: /freebsd/sbin/newfs/mkfs.c (revision 2be1a816b9ff69588e55be0a84cbe2a31efc0f2f)
1 /*
2  * Copyright (c) 2002 Networks Associates Technology, Inc.
3  * All rights reserved.
4  *
5  * This software was developed for the FreeBSD Project by Marshall
6  * Kirk McKusick and Network Associates Laboratories, the Security
7  * Research Division of Network Associates, Inc. under DARPA/SPAWAR
8  * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS
9  * research program.
10  *
11  * Copyright (c) 1980, 1989, 1993
12  *	The Regents of the University of California.  All rights reserved.
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  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  */
38 
39 #if 0
40 #ifndef lint
41 static char sccsid[] = "@(#)mkfs.c	8.11 (Berkeley) 5/3/95";
42 #endif /* not lint */
43 #endif
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
46 
47 #include <err.h>
48 #include <grp.h>
49 #include <limits.h>
50 #include <signal.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <stdint.h>
54 #include <stdio.h>
55 #include <unistd.h>
56 #include <sys/param.h>
57 #include <sys/time.h>
58 #include <sys/types.h>
59 #include <sys/wait.h>
60 #include <sys/resource.h>
61 #include <sys/stat.h>
62 #include <ufs/ufs/dinode.h>
63 #include <ufs/ufs/dir.h>
64 #include <ufs/ffs/fs.h>
65 #include <sys/disklabel.h>
66 #include <sys/file.h>
67 #include <sys/mman.h>
68 #include <sys/ioctl.h>
69 #include "newfs.h"
70 
71 /*
72  * make file system for cylinder-group style file systems
73  */
74 #define UMASK		0755
75 #define POWEROF2(num)	(((num) & ((num) - 1)) == 0)
76 
77 static struct	csum *fscs;
78 #define	sblock	disk.d_fs
79 #define	acg	disk.d_cg
80 
81 union dinode {
82 	struct ufs1_dinode dp1;
83 	struct ufs2_dinode dp2;
84 };
85 #define DIP(dp, field) \
86 	((sblock.fs_magic == FS_UFS1_MAGIC) ? \
87 	(dp)->dp1.field : (dp)->dp2.field)
88 
89 static caddr_t iobuf;
90 static long iobufsize;
91 static ufs2_daddr_t alloc(int size, int mode);
92 static int charsperline(void);
93 static void clrblock(struct fs *, unsigned char *, int);
94 static void fsinit(time_t);
95 static int ilog2(int);
96 static void initcg(int, time_t);
97 static int isblock(struct fs *, unsigned char *, int);
98 static void iput(union dinode *, ino_t);
99 static int makedir(struct direct *, int);
100 static void setblock(struct fs *, unsigned char *, int);
101 static void wtfs(ufs2_daddr_t, int, char *);
102 static u_int32_t newfs_random(void);
103 
104 void
105 mkfs(struct partition *pp, char *fsys)
106 {
107 	int fragsperinode, optimalfpg, origdensity, minfpg, lastminfpg;
108 	long i, j, cylno, csfrags;
109 	time_t utime;
110 	quad_t sizepb;
111 	int width;
112 	char tmpbuf[100];	/* XXX this will break in about 2,500 years */
113 	union {
114 		struct fs fdummy;
115 		char cdummy[SBLOCKSIZE];
116 	} dummy;
117 #define fsdummy dummy.fdummy
118 #define chdummy dummy.cdummy
119 
120 	/*
121 	 * Our blocks == sector size, and the version of UFS we are using is
122 	 * specified by Oflag.
123 	 */
124 	disk.d_bsize = sectorsize;
125 	disk.d_ufs = Oflag;
126 	if (Rflag) {
127 		utime = 1000000000;
128 	} else {
129 		time(&utime);
130 		arc4random_stir();
131 	}
132 	sblock.fs_old_flags = FS_FLAGS_UPDATED;
133 	sblock.fs_flags = 0;
134 	if (Uflag)
135 		sblock.fs_flags |= FS_DOSOFTDEP;
136 	if (Lflag)
137 		strlcpy(sblock.fs_volname, volumelabel, MAXVOLLEN);
138 	if (Jflag)
139 		sblock.fs_flags |= FS_GJOURNAL;
140 	if (lflag)
141 		sblock.fs_flags |= FS_MULTILABEL;
142 	/*
143 	 * Validate the given file system size.
144 	 * Verify that its last block can actually be accessed.
145 	 * Convert to file system fragment sized units.
146 	 */
147 	if (fssize <= 0) {
148 		printf("preposterous size %jd\n", (intmax_t)fssize);
149 		exit(13);
150 	}
151 	wtfs(fssize - (realsectorsize / DEV_BSIZE), realsectorsize,
152 	    (char *)&sblock);
153 	/*
154 	 * collect and verify the file system density info
155 	 */
156 	sblock.fs_avgfilesize = avgfilesize;
157 	sblock.fs_avgfpdir = avgfilesperdir;
158 	if (sblock.fs_avgfilesize <= 0)
159 		printf("illegal expected average file size %d\n",
160 		    sblock.fs_avgfilesize), exit(14);
161 	if (sblock.fs_avgfpdir <= 0)
162 		printf("illegal expected number of files per directory %d\n",
163 		    sblock.fs_avgfpdir), exit(15);
164 	/*
165 	 * collect and verify the block and fragment sizes
166 	 */
167 	sblock.fs_bsize = bsize;
168 	sblock.fs_fsize = fsize;
169 	if (!POWEROF2(sblock.fs_bsize)) {
170 		printf("block size must be a power of 2, not %d\n",
171 		    sblock.fs_bsize);
172 		exit(16);
173 	}
174 	if (!POWEROF2(sblock.fs_fsize)) {
175 		printf("fragment size must be a power of 2, not %d\n",
176 		    sblock.fs_fsize);
177 		exit(17);
178 	}
179 	if (sblock.fs_fsize < sectorsize) {
180 		printf("increasing fragment size from %d to sector size (%d)\n",
181 		    sblock.fs_fsize, sectorsize);
182 		sblock.fs_fsize = sectorsize;
183 	}
184 	if (sblock.fs_bsize > MAXBSIZE) {
185 		printf("decreasing block size from %d to maximum (%d)\n",
186 		    sblock.fs_bsize, MAXBSIZE);
187 		sblock.fs_bsize = MAXBSIZE;
188 	}
189 	if (sblock.fs_bsize < MINBSIZE) {
190 		printf("increasing block size from %d to minimum (%d)\n",
191 		    sblock.fs_bsize, MINBSIZE);
192 		sblock.fs_bsize = MINBSIZE;
193 	}
194 	if (sblock.fs_fsize > MAXBSIZE) {
195 		printf("decreasing fragment size from %d to maximum (%d)\n",
196 		    sblock.fs_fsize, MAXBSIZE);
197 		sblock.fs_fsize = MAXBSIZE;
198 	}
199 	if (sblock.fs_bsize < sblock.fs_fsize) {
200 		printf("increasing block size from %d to fragment size (%d)\n",
201 		    sblock.fs_bsize, sblock.fs_fsize);
202 		sblock.fs_bsize = sblock.fs_fsize;
203 	}
204 	if (sblock.fs_fsize * MAXFRAG < sblock.fs_bsize) {
205 		printf(
206 		"increasing fragment size from %d to block size / %d (%d)\n",
207 		    sblock.fs_fsize, MAXFRAG, sblock.fs_bsize / MAXFRAG);
208 		sblock.fs_fsize = sblock.fs_bsize / MAXFRAG;
209 	}
210 	if (maxbsize < bsize || !POWEROF2(maxbsize)) {
211 		sblock.fs_maxbsize = sblock.fs_bsize;
212 		printf("Extent size set to %d\n", sblock.fs_maxbsize);
213 	} else if (sblock.fs_maxbsize > FS_MAXCONTIG * sblock.fs_bsize) {
214 		sblock.fs_maxbsize = FS_MAXCONTIG * sblock.fs_bsize;
215 		printf("Extent size reduced to %d\n", sblock.fs_maxbsize);
216 	} else {
217 		sblock.fs_maxbsize = maxbsize;
218 	}
219 	sblock.fs_maxcontig = maxcontig;
220 	if (sblock.fs_maxcontig < sblock.fs_maxbsize / sblock.fs_bsize) {
221 		sblock.fs_maxcontig = sblock.fs_maxbsize / sblock.fs_bsize;
222 		printf("Maxcontig raised to %d\n", sblock.fs_maxbsize);
223 	}
224 	if (sblock.fs_maxcontig > 1)
225 		sblock.fs_contigsumsize = MIN(sblock.fs_maxcontig,FS_MAXCONTIG);
226 	sblock.fs_bmask = ~(sblock.fs_bsize - 1);
227 	sblock.fs_fmask = ~(sblock.fs_fsize - 1);
228 	sblock.fs_qbmask = ~sblock.fs_bmask;
229 	sblock.fs_qfmask = ~sblock.fs_fmask;
230 	sblock.fs_bshift = ilog2(sblock.fs_bsize);
231 	sblock.fs_fshift = ilog2(sblock.fs_fsize);
232 	sblock.fs_frag = numfrags(&sblock, sblock.fs_bsize);
233 	sblock.fs_fragshift = ilog2(sblock.fs_frag);
234 	if (sblock.fs_frag > MAXFRAG) {
235 		printf("fragment size %d is still too small (can't happen)\n",
236 		    sblock.fs_bsize / MAXFRAG);
237 		exit(21);
238 	}
239 	sblock.fs_fsbtodb = ilog2(sblock.fs_fsize / sectorsize);
240 	sblock.fs_size = fssize = dbtofsb(&sblock, fssize);
241 
242 	/*
243 	 * Before the filesystem is finally initialized, mark it
244 	 * as incompletely initialized.
245 	 */
246 	sblock.fs_magic = FS_BAD_MAGIC;
247 
248 	if (Oflag == 1) {
249 		sblock.fs_sblockloc = SBLOCK_UFS1;
250 		sblock.fs_nindir = sblock.fs_bsize / sizeof(ufs1_daddr_t);
251 		sblock.fs_inopb = sblock.fs_bsize / sizeof(struct ufs1_dinode);
252 		sblock.fs_maxsymlinklen = ((NDADDR + NIADDR) *
253 		    sizeof(ufs1_daddr_t));
254 		sblock.fs_old_inodefmt = FS_44INODEFMT;
255 		sblock.fs_old_cgoffset = 0;
256 		sblock.fs_old_cgmask = 0xffffffff;
257 		sblock.fs_old_size = sblock.fs_size;
258 		sblock.fs_old_rotdelay = 0;
259 		sblock.fs_old_rps = 60;
260 		sblock.fs_old_nspf = sblock.fs_fsize / sectorsize;
261 		sblock.fs_old_cpg = 1;
262 		sblock.fs_old_interleave = 1;
263 		sblock.fs_old_trackskew = 0;
264 		sblock.fs_old_cpc = 0;
265 		sblock.fs_old_postblformat = 1;
266 		sblock.fs_old_nrpos = 1;
267 	} else {
268 		sblock.fs_sblockloc = SBLOCK_UFS2;
269 		sblock.fs_nindir = sblock.fs_bsize / sizeof(ufs2_daddr_t);
270 		sblock.fs_inopb = sblock.fs_bsize / sizeof(struct ufs2_dinode);
271 		sblock.fs_maxsymlinklen = ((NDADDR + NIADDR) *
272 		    sizeof(ufs2_daddr_t));
273 	}
274 	sblock.fs_sblkno =
275 	    roundup(howmany(sblock.fs_sblockloc + SBLOCKSIZE, sblock.fs_fsize),
276 		sblock.fs_frag);
277 	sblock.fs_cblkno = sblock.fs_sblkno +
278 	    roundup(howmany(SBLOCKSIZE, sblock.fs_fsize), sblock.fs_frag);
279 	sblock.fs_iblkno = sblock.fs_cblkno + sblock.fs_frag;
280 	sblock.fs_maxfilesize = sblock.fs_bsize * NDADDR - 1;
281 	for (sizepb = sblock.fs_bsize, i = 0; i < NIADDR; i++) {
282 		sizepb *= NINDIR(&sblock);
283 		sblock.fs_maxfilesize += sizepb;
284 	}
285 
286 	/*
287 	 * It's impossible to create a snapshot in case that fs_maxfilesize
288 	 * is smaller than the fssize.
289 	 */
290 	if (sblock.fs_maxfilesize < (u_quad_t)fssize) {
291 		warnx("WARNING: You will be unable to create snapshots on this "
292 		      "file system.  Correct by using a larger blocksize.");
293 	}
294 
295 	/*
296 	 * Calculate the number of blocks to put into each cylinder group.
297 	 *
298 	 * This algorithm selects the number of blocks per cylinder
299 	 * group. The first goal is to have at least enough data blocks
300 	 * in each cylinder group to meet the density requirement. Once
301 	 * this goal is achieved we try to expand to have at least
302 	 * MINCYLGRPS cylinder groups. Once this goal is achieved, we
303 	 * pack as many blocks into each cylinder group map as will fit.
304 	 *
305 	 * We start by calculating the smallest number of blocks that we
306 	 * can put into each cylinder group. If this is too big, we reduce
307 	 * the density until it fits.
308 	 */
309 	origdensity = density;
310 	for (;;) {
311 		fragsperinode = MAX(numfrags(&sblock, density), 1);
312 		minfpg = fragsperinode * INOPB(&sblock);
313 		if (minfpg > sblock.fs_size)
314 			minfpg = sblock.fs_size;
315 		sblock.fs_ipg = INOPB(&sblock);
316 		sblock.fs_fpg = roundup(sblock.fs_iblkno +
317 		    sblock.fs_ipg / INOPF(&sblock), sblock.fs_frag);
318 		if (sblock.fs_fpg < minfpg)
319 			sblock.fs_fpg = minfpg;
320 		sblock.fs_ipg = roundup(howmany(sblock.fs_fpg, fragsperinode),
321 		    INOPB(&sblock));
322 		sblock.fs_fpg = roundup(sblock.fs_iblkno +
323 		    sblock.fs_ipg / INOPF(&sblock), sblock.fs_frag);
324 		if (sblock.fs_fpg < minfpg)
325 			sblock.fs_fpg = minfpg;
326 		sblock.fs_ipg = roundup(howmany(sblock.fs_fpg, fragsperinode),
327 		    INOPB(&sblock));
328 		if (CGSIZE(&sblock) < (unsigned long)sblock.fs_bsize)
329 			break;
330 		density -= sblock.fs_fsize;
331 	}
332 	if (density != origdensity)
333 		printf("density reduced from %d to %d\n", origdensity, density);
334 	/*
335 	 * Start packing more blocks into the cylinder group until
336 	 * it cannot grow any larger, the number of cylinder groups
337 	 * drops below MINCYLGRPS, or we reach the size requested.
338 	 */
339 	for ( ; sblock.fs_fpg < maxblkspercg; sblock.fs_fpg += sblock.fs_frag) {
340 		sblock.fs_ipg = roundup(howmany(sblock.fs_fpg, fragsperinode),
341 		    INOPB(&sblock));
342 		if (sblock.fs_size / sblock.fs_fpg < MINCYLGRPS)
343 			break;
344 		if (CGSIZE(&sblock) < (unsigned long)sblock.fs_bsize)
345 			continue;
346 		if (CGSIZE(&sblock) == (unsigned long)sblock.fs_bsize)
347 			break;
348 		sblock.fs_fpg -= sblock.fs_frag;
349 		sblock.fs_ipg = roundup(howmany(sblock.fs_fpg, fragsperinode),
350 		    INOPB(&sblock));
351 		break;
352 	}
353 	/*
354 	 * Check to be sure that the last cylinder group has enough blocks
355 	 * to be viable. If it is too small, reduce the number of blocks
356 	 * per cylinder group which will have the effect of moving more
357 	 * blocks into the last cylinder group.
358 	 */
359 	optimalfpg = sblock.fs_fpg;
360 	for (;;) {
361 		sblock.fs_ncg = howmany(sblock.fs_size, sblock.fs_fpg);
362 		lastminfpg = roundup(sblock.fs_iblkno +
363 		    sblock.fs_ipg / INOPF(&sblock), sblock.fs_frag);
364 		if (sblock.fs_size < lastminfpg) {
365 			printf("Filesystem size %jd < minimum size of %d\n",
366 			    (intmax_t)sblock.fs_size, lastminfpg);
367 			exit(28);
368 		}
369 		if (sblock.fs_size % sblock.fs_fpg >= lastminfpg ||
370 		    sblock.fs_size % sblock.fs_fpg == 0)
371 			break;
372 		sblock.fs_fpg -= sblock.fs_frag;
373 		sblock.fs_ipg = roundup(howmany(sblock.fs_fpg, fragsperinode),
374 		    INOPB(&sblock));
375 	}
376 	if (optimalfpg != sblock.fs_fpg)
377 		printf("Reduced frags per cylinder group from %d to %d %s\n",
378 		   optimalfpg, sblock.fs_fpg, "to enlarge last cyl group");
379 	sblock.fs_cgsize = fragroundup(&sblock, CGSIZE(&sblock));
380 	sblock.fs_dblkno = sblock.fs_iblkno + sblock.fs_ipg / INOPF(&sblock);
381 	if (Oflag == 1) {
382 		sblock.fs_old_spc = sblock.fs_fpg * sblock.fs_old_nspf;
383 		sblock.fs_old_nsect = sblock.fs_old_spc;
384 		sblock.fs_old_npsect = sblock.fs_old_spc;
385 		sblock.fs_old_ncyl = sblock.fs_ncg;
386 	}
387 	/*
388 	 * fill in remaining fields of the super block
389 	 */
390 	sblock.fs_csaddr = cgdmin(&sblock, 0);
391 	sblock.fs_cssize =
392 	    fragroundup(&sblock, sblock.fs_ncg * sizeof(struct csum));
393 	fscs = (struct csum *)calloc(1, sblock.fs_cssize);
394 	if (fscs == NULL)
395 		errx(31, "calloc failed");
396 	sblock.fs_sbsize = fragroundup(&sblock, sizeof(struct fs));
397 	if (sblock.fs_sbsize > SBLOCKSIZE)
398 		sblock.fs_sbsize = SBLOCKSIZE;
399 	sblock.fs_minfree = minfree;
400 	sblock.fs_maxbpg = maxbpg;
401 	sblock.fs_optim = opt;
402 	sblock.fs_cgrotor = 0;
403 	sblock.fs_pendingblocks = 0;
404 	sblock.fs_pendinginodes = 0;
405 	sblock.fs_fmod = 0;
406 	sblock.fs_ronly = 0;
407 	sblock.fs_state = 0;
408 	sblock.fs_clean = 1;
409 	sblock.fs_id[0] = (long)utime;
410 	sblock.fs_id[1] = newfs_random();
411 	sblock.fs_fsmnt[0] = '\0';
412 	csfrags = howmany(sblock.fs_cssize, sblock.fs_fsize);
413 	sblock.fs_dsize = sblock.fs_size - sblock.fs_sblkno -
414 	    sblock.fs_ncg * (sblock.fs_dblkno - sblock.fs_sblkno);
415 	sblock.fs_cstotal.cs_nbfree =
416 	    fragstoblks(&sblock, sblock.fs_dsize) -
417 	    howmany(csfrags, sblock.fs_frag);
418 	sblock.fs_cstotal.cs_nffree =
419 	    fragnum(&sblock, sblock.fs_size) +
420 	    (fragnum(&sblock, csfrags) > 0 ?
421 	     sblock.fs_frag - fragnum(&sblock, csfrags) : 0);
422 	sblock.fs_cstotal.cs_nifree = sblock.fs_ncg * sblock.fs_ipg - ROOTINO;
423 	sblock.fs_cstotal.cs_ndir = 0;
424 	sblock.fs_dsize -= csfrags;
425 	sblock.fs_time = utime;
426 	if (Oflag == 1) {
427 		sblock.fs_old_time = utime;
428 		sblock.fs_old_dsize = sblock.fs_dsize;
429 		sblock.fs_old_csaddr = sblock.fs_csaddr;
430 		sblock.fs_old_cstotal.cs_ndir = sblock.fs_cstotal.cs_ndir;
431 		sblock.fs_old_cstotal.cs_nbfree = sblock.fs_cstotal.cs_nbfree;
432 		sblock.fs_old_cstotal.cs_nifree = sblock.fs_cstotal.cs_nifree;
433 		sblock.fs_old_cstotal.cs_nffree = sblock.fs_cstotal.cs_nffree;
434 	}
435 
436 	/*
437 	 * Dump out summary information about file system.
438 	 */
439 #	define B2MBFACTOR (1 / (1024.0 * 1024.0))
440 	printf("%s: %.1fMB (%jd sectors) block size %d, fragment size %d\n",
441 	    fsys, (float)sblock.fs_size * sblock.fs_fsize * B2MBFACTOR,
442 	    (intmax_t)fsbtodb(&sblock, sblock.fs_size), sblock.fs_bsize,
443 	    sblock.fs_fsize);
444 	printf("\tusing %d cylinder groups of %.2fMB, %d blks, %d inodes.\n",
445 	    sblock.fs_ncg, (float)sblock.fs_fpg * sblock.fs_fsize * B2MBFACTOR,
446 	    sblock.fs_fpg / sblock.fs_frag, sblock.fs_ipg);
447 	if (sblock.fs_flags & FS_DOSOFTDEP)
448 		printf("\twith soft updates\n");
449 #	undef B2MBFACTOR
450 
451 	if (Eflag && !Nflag) {
452 		printf("Erasing sectors [%jd...%jd]\n",
453 		    sblock.fs_sblockloc / disk.d_bsize,
454 		    fsbtodb(&sblock, sblock.fs_size) - 1);
455 		berase(&disk, sblock.fs_sblockloc / disk.d_bsize,
456 		    sblock.fs_size * sblock.fs_fsize - sblock.fs_sblockloc);
457 	}
458 	/*
459 	 * Wipe out old UFS1 superblock(s) if necessary.
460 	 */
461 	if (!Nflag && Oflag != 1) {
462 		i = bread(&disk, SBLOCK_UFS1 / disk.d_bsize, chdummy, SBLOCKSIZE);
463 		if (i == -1)
464 			err(1, "can't read old UFS1 superblock: %s", disk.d_error);
465 
466 		if (fsdummy.fs_magic == FS_UFS1_MAGIC) {
467 			fsdummy.fs_magic = 0;
468 			bwrite(&disk, SBLOCK_UFS1 / disk.d_bsize, chdummy, SBLOCKSIZE);
469 			for (i = 0; i < fsdummy.fs_ncg; i++)
470 				bwrite(&disk, fsbtodb(&fsdummy, cgsblock(&fsdummy, i)),
471 	                    chdummy, SBLOCKSIZE);
472 		}
473 	}
474 	if (!Nflag)
475 		sbwrite(&disk, 0);
476 	if (Xflag == 1) {
477 		printf("** Exiting on Xflag 1\n");
478 		exit(0);
479 	}
480 	if (Xflag == 2)
481 		printf("** Leaving BAD MAGIC on Xflag 2\n");
482 	else
483 		sblock.fs_magic = (Oflag != 1) ? FS_UFS2_MAGIC : FS_UFS1_MAGIC;
484 
485 	/*
486 	 * Now build the cylinders group blocks and
487 	 * then print out indices of cylinder groups.
488 	 */
489 	printf("super-block backups (for fsck -b #) at:\n");
490 	i = 0;
491 	width = charsperline();
492 	/*
493 	 * allocate space for superblock, cylinder group map, and
494 	 * two sets of inode blocks.
495 	 */
496 	if (sblock.fs_bsize < SBLOCKSIZE)
497 		iobufsize = SBLOCKSIZE + 3 * sblock.fs_bsize;
498 	else
499 		iobufsize = 4 * sblock.fs_bsize;
500 	if ((iobuf = calloc(1, iobufsize)) == 0) {
501 		printf("Cannot allocate I/O buffer\n");
502 		exit(38);
503 	}
504 	/*
505 	 * Make a copy of the superblock into the buffer that we will be
506 	 * writing out in each cylinder group.
507 	 */
508 	bcopy((char *)&sblock, iobuf, SBLOCKSIZE);
509 	for (cylno = 0; cylno < sblock.fs_ncg; cylno++) {
510 		initcg(cylno, utime);
511 		j = snprintf(tmpbuf, sizeof(tmpbuf), " %jd%s",
512 		    (intmax_t)fsbtodb(&sblock, cgsblock(&sblock, cylno)),
513 		    cylno < (sblock.fs_ncg-1) ? "," : "");
514 		if (j < 0)
515 			tmpbuf[j = 0] = '\0';
516 		if (i + j >= width) {
517 			printf("\n");
518 			i = 0;
519 		}
520 		i += j;
521 		printf("%s", tmpbuf);
522 		fflush(stdout);
523 	}
524 	printf("\n");
525 	if (Nflag)
526 		exit(0);
527 	/*
528 	 * Now construct the initial file system,
529 	 * then write out the super-block.
530 	 */
531 	fsinit(utime);
532 	if (Oflag == 1) {
533 		sblock.fs_old_cstotal.cs_ndir = sblock.fs_cstotal.cs_ndir;
534 		sblock.fs_old_cstotal.cs_nbfree = sblock.fs_cstotal.cs_nbfree;
535 		sblock.fs_old_cstotal.cs_nifree = sblock.fs_cstotal.cs_nifree;
536 		sblock.fs_old_cstotal.cs_nffree = sblock.fs_cstotal.cs_nffree;
537 	}
538 	if (Xflag == 3) {
539 		printf("** Exiting on Xflag 3\n");
540 		exit(0);
541 	}
542 	if (!Nflag)
543 		sbwrite(&disk, 0);
544 	for (i = 0; i < sblock.fs_cssize; i += sblock.fs_bsize)
545 		wtfs(fsbtodb(&sblock, sblock.fs_csaddr + numfrags(&sblock, i)),
546 			sblock.fs_cssize - i < sblock.fs_bsize ?
547 			sblock.fs_cssize - i : sblock.fs_bsize,
548 			((char *)fscs) + i);
549 	/*
550 	 * Update information about this partion in pack
551 	 * label, to that it may be updated on disk.
552 	 */
553 	if (pp != NULL) {
554 		pp->p_fstype = FS_BSDFFS;
555 		pp->p_fsize = sblock.fs_fsize;
556 		pp->p_frag = sblock.fs_frag;
557 		pp->p_cpg = sblock.fs_fpg;
558 	}
559 }
560 
561 /*
562  * Initialize a cylinder group.
563  */
564 void
565 initcg(int cylno, time_t utime)
566 {
567 	long i, j, d, dlower, dupper, blkno, start;
568 	ufs2_daddr_t cbase, dmax;
569 	struct ufs1_dinode *dp1;
570 	struct ufs2_dinode *dp2;
571 	struct csum *cs;
572 
573 	/*
574 	 * Determine block bounds for cylinder group.
575 	 * Allow space for super block summary information in first
576 	 * cylinder group.
577 	 */
578 	cbase = cgbase(&sblock, cylno);
579 	dmax = cbase + sblock.fs_fpg;
580 	if (dmax > sblock.fs_size)
581 		dmax = sblock.fs_size;
582 	dlower = cgsblock(&sblock, cylno) - cbase;
583 	dupper = cgdmin(&sblock, cylno) - cbase;
584 	if (cylno == 0)
585 		dupper += howmany(sblock.fs_cssize, sblock.fs_fsize);
586 	cs = &fscs[cylno];
587 	memset(&acg, 0, sblock.fs_cgsize);
588 	acg.cg_time = utime;
589 	acg.cg_magic = CG_MAGIC;
590 	acg.cg_cgx = cylno;
591 	acg.cg_niblk = sblock.fs_ipg;
592 	acg.cg_initediblk = sblock.fs_ipg < 2 * INOPB(&sblock) ?
593 	    sblock.fs_ipg : 2 * INOPB(&sblock);
594 	acg.cg_ndblk = dmax - cbase;
595 	if (sblock.fs_contigsumsize > 0)
596 		acg.cg_nclusterblks = acg.cg_ndblk / sblock.fs_frag;
597 	start = &acg.cg_space[0] - (u_char *)(&acg.cg_firstfield);
598 	if (Oflag == 2) {
599 		acg.cg_iusedoff = start;
600 	} else {
601 		acg.cg_old_ncyl = sblock.fs_old_cpg;
602 		acg.cg_old_time = acg.cg_time;
603 		acg.cg_time = 0;
604 		acg.cg_old_niblk = acg.cg_niblk;
605 		acg.cg_niblk = 0;
606 		acg.cg_initediblk = 0;
607 		acg.cg_old_btotoff = start;
608 		acg.cg_old_boff = acg.cg_old_btotoff +
609 		    sblock.fs_old_cpg * sizeof(int32_t);
610 		acg.cg_iusedoff = acg.cg_old_boff +
611 		    sblock.fs_old_cpg * sizeof(u_int16_t);
612 	}
613 	acg.cg_freeoff = acg.cg_iusedoff + howmany(sblock.fs_ipg, CHAR_BIT);
614 	acg.cg_nextfreeoff = acg.cg_freeoff + howmany(sblock.fs_fpg, CHAR_BIT);
615 	if (sblock.fs_contigsumsize > 0) {
616 		acg.cg_clustersumoff =
617 		    roundup(acg.cg_nextfreeoff, sizeof(u_int32_t));
618 		acg.cg_clustersumoff -= sizeof(u_int32_t);
619 		acg.cg_clusteroff = acg.cg_clustersumoff +
620 		    (sblock.fs_contigsumsize + 1) * sizeof(u_int32_t);
621 		acg.cg_nextfreeoff = acg.cg_clusteroff +
622 		    howmany(fragstoblks(&sblock, sblock.fs_fpg), CHAR_BIT);
623 	}
624 	if (acg.cg_nextfreeoff > sblock.fs_cgsize) {
625 		printf("Panic: cylinder group too big\n");
626 		exit(37);
627 	}
628 	acg.cg_cs.cs_nifree += sblock.fs_ipg;
629 	if (cylno == 0)
630 		for (i = 0; i < (long)ROOTINO; i++) {
631 			setbit(cg_inosused(&acg), i);
632 			acg.cg_cs.cs_nifree--;
633 		}
634 	if (cylno > 0) {
635 		/*
636 		 * In cylno 0, beginning space is reserved
637 		 * for boot and super blocks.
638 		 */
639 		for (d = 0; d < dlower; d += sblock.fs_frag) {
640 			blkno = d / sblock.fs_frag;
641 			setblock(&sblock, cg_blksfree(&acg), blkno);
642 			if (sblock.fs_contigsumsize > 0)
643 				setbit(cg_clustersfree(&acg), blkno);
644 			acg.cg_cs.cs_nbfree++;
645 		}
646 	}
647 	if ((i = dupper % sblock.fs_frag)) {
648 		acg.cg_frsum[sblock.fs_frag - i]++;
649 		for (d = dupper + sblock.fs_frag - i; dupper < d; dupper++) {
650 			setbit(cg_blksfree(&acg), dupper);
651 			acg.cg_cs.cs_nffree++;
652 		}
653 	}
654 	for (d = dupper; d + sblock.fs_frag <= acg.cg_ndblk;
655 	     d += sblock.fs_frag) {
656 		blkno = d / sblock.fs_frag;
657 		setblock(&sblock, cg_blksfree(&acg), blkno);
658 		if (sblock.fs_contigsumsize > 0)
659 			setbit(cg_clustersfree(&acg), blkno);
660 		acg.cg_cs.cs_nbfree++;
661 	}
662 	if (d < acg.cg_ndblk) {
663 		acg.cg_frsum[acg.cg_ndblk - d]++;
664 		for (; d < acg.cg_ndblk; d++) {
665 			setbit(cg_blksfree(&acg), d);
666 			acg.cg_cs.cs_nffree++;
667 		}
668 	}
669 	if (sblock.fs_contigsumsize > 0) {
670 		int32_t *sump = cg_clustersum(&acg);
671 		u_char *mapp = cg_clustersfree(&acg);
672 		int map = *mapp++;
673 		int bit = 1;
674 		int run = 0;
675 
676 		for (i = 0; i < acg.cg_nclusterblks; i++) {
677 			if ((map & bit) != 0)
678 				run++;
679 			else if (run != 0) {
680 				if (run > sblock.fs_contigsumsize)
681 					run = sblock.fs_contigsumsize;
682 				sump[run]++;
683 				run = 0;
684 			}
685 			if ((i & (CHAR_BIT - 1)) != CHAR_BIT - 1)
686 				bit <<= 1;
687 			else {
688 				map = *mapp++;
689 				bit = 1;
690 			}
691 		}
692 		if (run != 0) {
693 			if (run > sblock.fs_contigsumsize)
694 				run = sblock.fs_contigsumsize;
695 			sump[run]++;
696 		}
697 	}
698 	*cs = acg.cg_cs;
699 	/*
700 	 * Write out the duplicate super block, the cylinder group map
701 	 * and two blocks worth of inodes in a single write.
702 	 */
703 	start = sblock.fs_bsize > SBLOCKSIZE ? sblock.fs_bsize : SBLOCKSIZE;
704 	bcopy((char *)&acg, &iobuf[start], sblock.fs_cgsize);
705 	start += sblock.fs_bsize;
706 	dp1 = (struct ufs1_dinode *)(&iobuf[start]);
707 	dp2 = (struct ufs2_dinode *)(&iobuf[start]);
708 	for (i = 0; i < acg.cg_initediblk; i++) {
709 		if (sblock.fs_magic == FS_UFS1_MAGIC) {
710 			dp1->di_gen = newfs_random();
711 			dp1++;
712 		} else {
713 			dp2->di_gen = newfs_random();
714 			dp2++;
715 		}
716 	}
717 	wtfs(fsbtodb(&sblock, cgsblock(&sblock, cylno)), iobufsize, iobuf);
718 	/*
719 	 * For the old file system, we have to initialize all the inodes.
720 	 */
721 	if (Oflag == 1) {
722 		for (i = 2 * sblock.fs_frag;
723 		     i < sblock.fs_ipg / INOPF(&sblock);
724 		     i += sblock.fs_frag) {
725 			dp1 = (struct ufs1_dinode *)(&iobuf[start]);
726 			for (j = 0; j < INOPB(&sblock); j++) {
727 				dp1->di_gen = newfs_random();
728 				dp1++;
729 			}
730 			wtfs(fsbtodb(&sblock, cgimin(&sblock, cylno) + i),
731 			    sblock.fs_bsize, &iobuf[start]);
732 		}
733 	}
734 }
735 
736 /*
737  * initialize the file system
738  */
739 #define ROOTLINKCNT 3
740 
741 struct direct root_dir[] = {
742 	{ ROOTINO, sizeof(struct direct), DT_DIR, 1, "." },
743 	{ ROOTINO, sizeof(struct direct), DT_DIR, 2, ".." },
744 	{ ROOTINO + 1, sizeof(struct direct), DT_DIR, 5, ".snap" },
745 };
746 
747 #define SNAPLINKCNT 2
748 
749 struct direct snap_dir[] = {
750 	{ ROOTINO + 1, sizeof(struct direct), DT_DIR, 1, "." },
751 	{ ROOTINO, sizeof(struct direct), DT_DIR, 2, ".." },
752 };
753 
754 void
755 fsinit(time_t utime)
756 {
757 	union dinode node;
758 	struct group *grp;
759 	gid_t gid;
760 	int entries;
761 
762 	memset(&node, 0, sizeof node);
763 	if ((grp = getgrnam("operator")) != NULL) {
764 		gid = grp->gr_gid;
765 	} else {
766 		warnx("Cannot retrieve operator gid, using gid 0.");
767 		gid = 0;
768 	}
769 	entries = (nflag) ? ROOTLINKCNT - 1: ROOTLINKCNT;
770 	if (sblock.fs_magic == FS_UFS1_MAGIC) {
771 		/*
772 		 * initialize the node
773 		 */
774 		node.dp1.di_atime = utime;
775 		node.dp1.di_mtime = utime;
776 		node.dp1.di_ctime = utime;
777 		/*
778 		 * create the root directory
779 		 */
780 		node.dp1.di_mode = IFDIR | UMASK;
781 		node.dp1.di_nlink = entries;
782 		node.dp1.di_size = makedir(root_dir, entries);
783 		node.dp1.di_db[0] = alloc(sblock.fs_fsize, node.dp1.di_mode);
784 		node.dp1.di_blocks =
785 		    btodb(fragroundup(&sblock, node.dp1.di_size));
786 		wtfs(fsbtodb(&sblock, node.dp1.di_db[0]), sblock.fs_fsize,
787 		    iobuf);
788 		iput(&node, ROOTINO);
789 		if (!nflag) {
790 			/*
791 			 * create the .snap directory
792 			 */
793 			node.dp1.di_mode |= 020;
794 			node.dp1.di_gid = gid;
795 			node.dp1.di_nlink = SNAPLINKCNT;
796 			node.dp1.di_size = makedir(snap_dir, SNAPLINKCNT);
797 				node.dp1.di_db[0] =
798 				    alloc(sblock.fs_fsize, node.dp1.di_mode);
799 			node.dp1.di_blocks =
800 			    btodb(fragroundup(&sblock, node.dp1.di_size));
801 				wtfs(fsbtodb(&sblock, node.dp1.di_db[0]),
802 				    sblock.fs_fsize, iobuf);
803 			iput(&node, ROOTINO + 1);
804 		}
805 	} else {
806 		/*
807 		 * initialize the node
808 		 */
809 		node.dp2.di_atime = utime;
810 		node.dp2.di_mtime = utime;
811 		node.dp2.di_ctime = utime;
812 		node.dp2.di_birthtime = utime;
813 		/*
814 		 * create the root directory
815 		 */
816 		node.dp2.di_mode = IFDIR | UMASK;
817 		node.dp2.di_nlink = entries;
818 		node.dp2.di_size = makedir(root_dir, entries);
819 		node.dp2.di_db[0] = alloc(sblock.fs_fsize, node.dp2.di_mode);
820 		node.dp2.di_blocks =
821 		    btodb(fragroundup(&sblock, node.dp2.di_size));
822 		wtfs(fsbtodb(&sblock, node.dp2.di_db[0]), sblock.fs_fsize,
823 		    iobuf);
824 		iput(&node, ROOTINO);
825 		if (!nflag) {
826 			/*
827 			 * create the .snap directory
828 			 */
829 			node.dp2.di_mode |= 020;
830 			node.dp2.di_gid = gid;
831 			node.dp2.di_nlink = SNAPLINKCNT;
832 			node.dp2.di_size = makedir(snap_dir, SNAPLINKCNT);
833 				node.dp2.di_db[0] =
834 				    alloc(sblock.fs_fsize, node.dp2.di_mode);
835 			node.dp2.di_blocks =
836 			    btodb(fragroundup(&sblock, node.dp2.di_size));
837 				wtfs(fsbtodb(&sblock, node.dp2.di_db[0]),
838 				    sblock.fs_fsize, iobuf);
839 			iput(&node, ROOTINO + 1);
840 		}
841 	}
842 }
843 
844 /*
845  * construct a set of directory entries in "iobuf".
846  * return size of directory.
847  */
848 int
849 makedir(struct direct *protodir, int entries)
850 {
851 	char *cp;
852 	int i, spcleft;
853 
854 	spcleft = DIRBLKSIZ;
855 	memset(iobuf, 0, DIRBLKSIZ);
856 	for (cp = iobuf, i = 0; i < entries - 1; i++) {
857 		protodir[i].d_reclen = DIRSIZ(0, &protodir[i]);
858 		memmove(cp, &protodir[i], protodir[i].d_reclen);
859 		cp += protodir[i].d_reclen;
860 		spcleft -= protodir[i].d_reclen;
861 	}
862 	protodir[i].d_reclen = spcleft;
863 	memmove(cp, &protodir[i], DIRSIZ(0, &protodir[i]));
864 	return (DIRBLKSIZ);
865 }
866 
867 /*
868  * allocate a block or frag
869  */
870 ufs2_daddr_t
871 alloc(int size, int mode)
872 {
873 	int i, d, blkno, frag;
874 
875 	bread(&disk, fsbtodb(&sblock, cgtod(&sblock, 0)), (char *)&acg,
876 	    sblock.fs_cgsize);
877 	if (acg.cg_magic != CG_MAGIC) {
878 		printf("cg 0: bad magic number\n");
879 		exit(38);
880 	}
881 	if (acg.cg_cs.cs_nbfree == 0) {
882 		printf("first cylinder group ran out of space\n");
883 		exit(39);
884 	}
885 	for (d = 0; d < acg.cg_ndblk; d += sblock.fs_frag)
886 		if (isblock(&sblock, cg_blksfree(&acg), d / sblock.fs_frag))
887 			goto goth;
888 	printf("internal error: can't find block in cyl 0\n");
889 	exit(40);
890 goth:
891 	blkno = fragstoblks(&sblock, d);
892 	clrblock(&sblock, cg_blksfree(&acg), blkno);
893 	if (sblock.fs_contigsumsize > 0)
894 		clrbit(cg_clustersfree(&acg), blkno);
895 	acg.cg_cs.cs_nbfree--;
896 	sblock.fs_cstotal.cs_nbfree--;
897 	fscs[0].cs_nbfree--;
898 	if (mode & IFDIR) {
899 		acg.cg_cs.cs_ndir++;
900 		sblock.fs_cstotal.cs_ndir++;
901 		fscs[0].cs_ndir++;
902 	}
903 	if (size != sblock.fs_bsize) {
904 		frag = howmany(size, sblock.fs_fsize);
905 		fscs[0].cs_nffree += sblock.fs_frag - frag;
906 		sblock.fs_cstotal.cs_nffree += sblock.fs_frag - frag;
907 		acg.cg_cs.cs_nffree += sblock.fs_frag - frag;
908 		acg.cg_frsum[sblock.fs_frag - frag]++;
909 		for (i = frag; i < sblock.fs_frag; i++)
910 			setbit(cg_blksfree(&acg), d + i);
911 	}
912 	/* XXX cgwrite(&disk, 0)??? */
913 	wtfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize,
914 	    (char *)&acg);
915 	return ((ufs2_daddr_t)d);
916 }
917 
918 /*
919  * Allocate an inode on the disk
920  */
921 void
922 iput(union dinode *ip, ino_t ino)
923 {
924 	ufs2_daddr_t d;
925 	int c;
926 
927 	c = ino_to_cg(&sblock, ino);
928 	bread(&disk, fsbtodb(&sblock, cgtod(&sblock, 0)), (char *)&acg,
929 	    sblock.fs_cgsize);
930 	if (acg.cg_magic != CG_MAGIC) {
931 		printf("cg 0: bad magic number\n");
932 		exit(31);
933 	}
934 	acg.cg_cs.cs_nifree--;
935 	setbit(cg_inosused(&acg), ino);
936 	wtfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize,
937 	    (char *)&acg);
938 	sblock.fs_cstotal.cs_nifree--;
939 	fscs[0].cs_nifree--;
940 	if (ino >= (unsigned long)sblock.fs_ipg * sblock.fs_ncg) {
941 		printf("fsinit: inode value out of range (%d).\n", ino);
942 		exit(32);
943 	}
944 	d = fsbtodb(&sblock, ino_to_fsba(&sblock, ino));
945 	bread(&disk, d, (char *)iobuf, sblock.fs_bsize);
946 	if (sblock.fs_magic == FS_UFS1_MAGIC)
947 		((struct ufs1_dinode *)iobuf)[ino_to_fsbo(&sblock, ino)] =
948 		    ip->dp1;
949 	else
950 		((struct ufs2_dinode *)iobuf)[ino_to_fsbo(&sblock, ino)] =
951 		    ip->dp2;
952 	wtfs(d, sblock.fs_bsize, (char *)iobuf);
953 }
954 
955 /*
956  * possibly write to disk
957  */
958 static void
959 wtfs(ufs2_daddr_t bno, int size, char *bf)
960 {
961 	if (Nflag)
962 		return;
963 	if (bwrite(&disk, bno, bf, size) < 0)
964 		err(36, "wtfs: %d bytes at sector %jd", size, (intmax_t)bno);
965 }
966 
967 /*
968  * check if a block is available
969  */
970 static int
971 isblock(struct fs *fs, unsigned char *cp, int h)
972 {
973 	unsigned char mask;
974 
975 	switch (fs->fs_frag) {
976 	case 8:
977 		return (cp[h] == 0xff);
978 	case 4:
979 		mask = 0x0f << ((h & 0x1) << 2);
980 		return ((cp[h >> 1] & mask) == mask);
981 	case 2:
982 		mask = 0x03 << ((h & 0x3) << 1);
983 		return ((cp[h >> 2] & mask) == mask);
984 	case 1:
985 		mask = 0x01 << (h & 0x7);
986 		return ((cp[h >> 3] & mask) == mask);
987 	default:
988 		fprintf(stderr, "isblock bad fs_frag %d\n", fs->fs_frag);
989 		return (0);
990 	}
991 }
992 
993 /*
994  * take a block out of the map
995  */
996 static void
997 clrblock(struct fs *fs, unsigned char *cp, int h)
998 {
999 	switch ((fs)->fs_frag) {
1000 	case 8:
1001 		cp[h] = 0;
1002 		return;
1003 	case 4:
1004 		cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2));
1005 		return;
1006 	case 2:
1007 		cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1));
1008 		return;
1009 	case 1:
1010 		cp[h >> 3] &= ~(0x01 << (h & 0x7));
1011 		return;
1012 	default:
1013 		fprintf(stderr, "clrblock bad fs_frag %d\n", fs->fs_frag);
1014 		return;
1015 	}
1016 }
1017 
1018 /*
1019  * put a block into the map
1020  */
1021 static void
1022 setblock(struct fs *fs, unsigned char *cp, int h)
1023 {
1024 	switch (fs->fs_frag) {
1025 	case 8:
1026 		cp[h] = 0xff;
1027 		return;
1028 	case 4:
1029 		cp[h >> 1] |= (0x0f << ((h & 0x1) << 2));
1030 		return;
1031 	case 2:
1032 		cp[h >> 2] |= (0x03 << ((h & 0x3) << 1));
1033 		return;
1034 	case 1:
1035 		cp[h >> 3] |= (0x01 << (h & 0x7));
1036 		return;
1037 	default:
1038 		fprintf(stderr, "setblock bad fs_frag %d\n", fs->fs_frag);
1039 		return;
1040 	}
1041 }
1042 
1043 /*
1044  * Determine the number of characters in a
1045  * single line.
1046  */
1047 
1048 static int
1049 charsperline(void)
1050 {
1051 	int columns;
1052 	char *cp;
1053 	struct winsize ws;
1054 
1055 	columns = 0;
1056 	if (ioctl(0, TIOCGWINSZ, &ws) != -1)
1057 		columns = ws.ws_col;
1058 	if (columns == 0 && (cp = getenv("COLUMNS")))
1059 		columns = atoi(cp);
1060 	if (columns == 0)
1061 		columns = 80;	/* last resort */
1062 	return (columns);
1063 }
1064 
1065 static int
1066 ilog2(int val)
1067 {
1068 	u_int n;
1069 
1070 	for (n = 0; n < sizeof(n) * CHAR_BIT; n++)
1071 		if (1 << n == val)
1072 			return (n);
1073 	errx(1, "ilog2: %d is not a power of 2\n", val);
1074 }
1075 
1076 /*
1077  * For the regression test, return predictable random values.
1078  * Otherwise use a true random number generator.
1079  */
1080 static u_int32_t
1081 newfs_random(void)
1082 {
1083 	static int nextnum = 1;
1084 
1085 	if (Rflag)
1086 		return (nextnum++);
1087 	return (arc4random());
1088 }
1089