xref: /openbsd-src/sbin/fsck_ext2fs/setup.c (revision f6aab3d83b51b91c24247ad2c2573574de475a82)
1 /*	$OpenBSD: setup.c,v 1.33 2019/07/01 07:13:44 kevlo Exp $	*/
2 /*	$NetBSD: setup.c,v 1.1 1997/06/11 11:22:01 bouyer Exp $	*/
3 
4 /*
5  * Copyright (c) 1997 Manuel Bouyer.
6  * Copyright (c) 1980, 1986, 1993
7  *	The Regents of the University of California.  All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #define DKTYPENAMES
35 #include <sys/param.h>	/* DEV_BSIZE roundup */
36 #include <sys/time.h>
37 #include <ufs/ext2fs/ext2fs_dinode.h>
38 #include <ufs/ext2fs/ext2fs.h>
39 #include <sys/stat.h>
40 #include <sys/ioctl.h>
41 #include <sys/dkio.h>
42 #include <sys/disklabel.h>
43 
44 #include <errno.h>
45 #include <fcntl.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <unistd.h>
49 #include <string.h>
50 #include <ctype.h>
51 #include <err.h>
52 
53 #include "fsck.h"
54 #include "extern.h"
55 #include "fsutil.h"
56 
57 #define POWEROF2(num)	(((num) & ((num) - 1)) == 0)
58 
59 void badsb(int, char *);
60 int calcsb(char *, int, struct m_ext2fs *, struct disklabel *);
61 static struct disklabel *getdisklabel(char *, int);
62 static int readsb(int);
63 
64 int
65 setup(char *dev)
66 {
67 	long cg, asked, i;
68 	long bmapsize;
69 	struct disklabel *lp;
70 	off_t sizepb;
71 	struct stat statb;
72 	struct m_ext2fs proto;
73 	int doskipclean;
74 	u_int64_t maxfilesize;
75 
76 	havesb = 0;
77 	fswritefd = -1;
78 	doskipclean = skipclean;
79 	if (stat(dev, &statb) == -1) {
80 		printf("Can't stat %s: %s\n", dev, strerror(errno));
81 		return (0);
82 	}
83 	if (!S_ISCHR(statb.st_mode)) {
84 		pfatal("%s is not a character device", dev);
85 		if (reply("CONTINUE") == 0)
86 			return (0);
87 	}
88 	if ((fsreadfd = open(dev, O_RDONLY)) == -1) {
89 		printf("Can't open %s: %s\n", dev, strerror(errno));
90 		return (0);
91 	}
92 	if (preen == 0)
93 		printf("** %s", dev);
94 	if (nflag || (fswritefd = open(dev, O_WRONLY)) == -1) {
95 		fswritefd = -1;
96 		if (preen)
97 			pfatal("NO WRITE ACCESS");
98 		printf(" (NO WRITE)");
99 	}
100 	if (preen == 0)
101 		printf("\n");
102 	fsmodified = 0;
103 	lfdir = 0;
104 	initbarea(&sblk);
105 	initbarea(&asblk);
106 	sblk.b_un.b_buf = malloc(SBSIZE);
107 	asblk.b_un.b_buf = malloc(SBSIZE);
108 	if (sblk.b_un.b_buf == NULL || asblk.b_un.b_buf == NULL)
109 		errexit("cannot allocate space for superblock\n");
110 	if ((lp = getdisklabel(NULL, fsreadfd)) != NULL)
111 		secsize = lp->d_secsize;
112 	else
113 		secsize = DEV_BSIZE;
114 
115 	if (!hotroot()) {
116 #ifndef SMALL
117 		if (pledge("stdio getpw", NULL) == -1)
118 			err(1, "pledge");
119 #else
120 		if (pledge("stdio", NULL) == -1)
121 			err(1, "pledge");
122 #endif
123 	}
124 
125 	/*
126 	 * Read in the superblock, looking for alternates if necessary
127 	 */
128 	if (readsb(1) == 0) {
129 		if (bflag || preen || calcsb(dev, fsreadfd, &proto, lp) == 0)
130 			return(0);
131 		if (reply("LOOK FOR ALTERNATE SUPERBLOCKS") == 0)
132 			return (0);
133 		for (cg = 1; cg < proto.e2fs_ncg; cg++) {
134 			bflag = fsbtodb(&proto,
135 				cg * proto.e2fs.e2fs_bpg + proto.e2fs.e2fs_first_dblock);
136 			if (readsb(0) != 0)
137 				break;
138 		}
139 		if (cg >= proto.e2fs_ncg) {
140 			printf("%s %s\n%s %s\n%s %s\n",
141 			    "SEARCH FOR ALTERNATE SUPER-BLOCK",
142 			    "FAILED. YOU MUST USE THE",
143 			    "-b OPTION TO FSCK_FFS TO SPECIFY THE",
144 			    "LOCATION OF AN ALTERNATE",
145 			    "SUPER-BLOCK TO SUPPLY NEEDED",
146 			    "INFORMATION; SEE fsck_ext2fs(8).");
147 			return(0);
148 		}
149 		doskipclean = 0;
150 		pwarn("USING ALTERNATE SUPERBLOCK AT %d\n", bflag);
151 	}
152 	if (debug)
153 		printf("state = %d\n", sblock.e2fs.e2fs_state);
154 	if (sblock.e2fs.e2fs_state == E2FS_ISCLEAN) {
155 		if (doskipclean) {
156 			pwarn("%sile system is clean; not checking\n",
157 			    preen ? "f" : "** F");
158 			return (-1);
159 		}
160 		if (!preen)
161 			pwarn("** File system is already clean\n");
162 	}
163 	maxfsblock = sblock.e2fs.e2fs_bcount;
164 	maxino = sblock.e2fs_ncg * sblock.e2fs.e2fs_ipg;
165 	sizepb = sblock.e2fs_bsize;
166 	maxfilesize = sblock.e2fs_bsize * NDADDR - 1;
167 	for (i = 0; i < NIADDR; i++) {
168 		sizepb *= NINDIR(&sblock);
169 		maxfilesize += sizepb;
170 	}
171 	/*
172 	 * Check and potentially fix certain fields in the super block.
173 	 */
174 	if (/* (sblock.e2fs.e2fs_rbcount < 0) || */
175 			(sblock.e2fs.e2fs_rbcount > sblock.e2fs.e2fs_bcount)) {
176 		pfatal("IMPOSSIBLE RESERVED BLOCK COUNT=%d IN SUPERBLOCK",
177 			sblock.e2fs.e2fs_rbcount);
178 		if (reply("SET TO DEFAULT") == 1) {
179 			sblock.e2fs.e2fs_rbcount = sblock.e2fs.e2fs_bcount * 0.1;
180 			sbdirty();
181 			dirty(&asblk);
182 		}
183 	}
184 	if (sblock.e2fs.e2fs_bpg != sblock.e2fs.e2fs_fpg) {
185 		pfatal("WRONG FPG=%d (BPG=%d) IN SUPERBLOCK",
186 			sblock.e2fs.e2fs_fpg, sblock.e2fs.e2fs_bpg);
187 		return 0;
188 	}
189 	if (asblk.b_dirty && !bflag) {
190 		copyback_sb(&asblk);
191 		flush(fswritefd, &asblk);
192 	}
193 	/*
194 	 * read in the summary info.
195 	 */
196 
197 	sblock.e2fs_gd = calloc(sblock.e2fs_ngdb, sblock.e2fs_bsize);
198 	if (sblock.e2fs_gd == NULL)
199 		errexit("out of memory\n");
200 	asked = 0;
201 	for (i=0; i < sblock.e2fs_ngdb; i++) {
202 		if (bread(fsreadfd,(char *)
203 			&sblock.e2fs_gd[i* sblock.e2fs_bsize / sizeof(struct ext2_gd)],
204 			fsbtodb(&sblock, ((sblock.e2fs_bsize>1024)?0:1)+i+1),
205 			sblock.e2fs_bsize) != 0 && !asked) {
206 			pfatal("BAD SUMMARY INFORMATION");
207 			if (reply("CONTINUE") == 0)
208 				errexit("%s\n", "");
209 			asked++;
210 		}
211 	}
212 	/*
213 	 * allocate and initialize the necessary maps
214 	 */
215 	bmapsize = roundup(howmany(maxfsblock, NBBY), sizeof(int16_t));
216 	blockmap = calloc((unsigned)bmapsize, sizeof (char));
217 	if (blockmap == NULL) {
218 		printf("cannot alloc %u bytes for blockmap\n",
219 			(unsigned)bmapsize);
220 		goto badsblabel;
221 	}
222 	statemap = calloc((unsigned)(maxino + 2), sizeof(char));
223 	if (statemap == NULL) {
224 		printf("cannot alloc %u bytes for statemap\n",
225 			(unsigned)(maxino + 1));
226 		goto badsblabel;
227 	}
228 	typemap = calloc((unsigned)(maxino + 1), sizeof(u_char));
229 	if (typemap == NULL) {
230 		printf("cannot alloc %u bytes for typemap\n",
231 		    (unsigned)(maxino + 1));
232 		goto badsblabel;
233 	}
234 	lncntp = calloc((unsigned)(maxino + 1), sizeof(int16_t));
235 	if (lncntp == NULL) {
236 		printf("cannot alloc %u bytes for lncntp\n",
237 			(unsigned)((maxino + 1) * sizeof(int16_t)));
238 		goto badsblabel;
239 	}
240 	for (numdirs = 0, cg = 0; cg < sblock.e2fs_ncg; cg++) {
241 		numdirs += letoh16(sblock.e2fs_gd[cg].ext2bgd_ndirs);
242 	}
243 	inplast = 0;
244 	listmax = numdirs + 10;
245 	inpsort = calloc((unsigned)listmax, sizeof(struct inoinfo *));
246 	inphead = calloc((unsigned)numdirs, sizeof(struct inoinfo *));
247 	if (inpsort == NULL || inphead == NULL) {
248 		printf("cannot alloc %u bytes for inphead\n",
249 			(unsigned)(numdirs * sizeof(struct inoinfo *)));
250 		goto badsblabel;
251 	}
252 	bufinit();
253 	return (1);
254 
255 badsblabel:
256 	ckfini(0);
257 	return (0);
258 }
259 
260 /*
261  * Read in the super block and its summary info.
262  */
263 static int
264 readsb(int listerr)
265 {
266 	daddr32_t super = bflag ? bflag : SBOFF / DEV_BSIZE;
267 
268 	if (bread(fsreadfd, (char *)sblk.b_un.b_fs, super, (long)SBSIZE) != 0)
269 		return (0);
270 	sblk.b_bno = super;
271 	sblk.b_size = SBSIZE;
272 
273 	/* Copy the superblock in memory */
274 	e2fs_sbload(sblk.b_un.b_fs, &sblock.e2fs);
275 
276 	/*
277 	 * run a few consistency checks of the super block
278 	 */
279 	if (sblock.e2fs.e2fs_magic != E2FS_MAGIC) {
280 		badsb(listerr, "MAGIC NUMBER WRONG"); return (0);
281 	}
282 	if (sblock.e2fs.e2fs_log_bsize > 2) {
283 		badsb(listerr, "BAD LOG_BSIZE"); return (0);
284 	}
285 	if (sblock.e2fs.e2fs_bpg == 0) {
286 		badsb(listerr, "BAD BLOCKS PER GROUP"); return (0);
287 	}
288 
289 	/* compute the dynamic fields of the in-memory sb */
290 	/* compute dynamic sb infos */
291 	sblock.e2fs_ncg =
292 		howmany(sblock.e2fs.e2fs_bcount - sblock.e2fs.e2fs_first_dblock,
293 		sblock.e2fs.e2fs_bpg);
294 	/* XXX assume hw bsize = 512 */
295 	sblock.e2fs_fsbtodb = sblock.e2fs.e2fs_log_bsize + 1;
296 	sblock.e2fs_bsize = 1024 << sblock.e2fs.e2fs_log_bsize;
297 	sblock.e2fs_bshift = LOG_MINBSIZE + sblock.e2fs.e2fs_log_bsize;
298 	sblock.e2fs_qbmask = sblock.e2fs_bsize - 1;
299 	sblock.e2fs_bmask = ~sblock.e2fs_qbmask;
300 	sblock.e2fs_ngdb = howmany(sblock.e2fs_ncg,
301 		sblock.e2fs_bsize / sizeof(struct ext2_gd));
302 	sblock.e2fs_ipb = sblock.e2fs_bsize / EXT2_DINODE_SIZE(&sblock);
303 	sblock.e2fs_itpg = sblock.e2fs.e2fs_ipg/sblock.e2fs_ipb;
304 
305 	/*
306 	 * Compute block size that the filesystem is based on,
307 	 * according to fsbtodb, and adjust superblock block number
308 	 * so we can tell if this is an alternate later.
309 	 */
310 	sblk.b_bno = super / DEV_BSIZE;
311 
312 	if (sblock.e2fs_ncg == 1) {
313 		/* no alternate superblock; assume it's okey */
314 		havesb = 1;
315 		return 1;
316 	}
317 
318 	getblk(&asblk, 1 * sblock.e2fs.e2fs_bpg + sblock.e2fs.e2fs_first_dblock,
319 		(long)SBSIZE);
320 	if (asblk.b_errs)
321 		return (0);
322 	if (bflag) {
323 		havesb = 1;
324 		return (1);
325 	}
326 
327 	/*
328 	 * Set all possible fields that could differ, then do check
329 	 * of whole super block against an alternate super block.
330 	 * When an alternate super-block is specified this check is skipped.
331 	 */
332 	asblk.b_un.b_fs->e2fs_rbcount = sblk.b_un.b_fs->e2fs_rbcount;
333 	asblk.b_un.b_fs->e2fs_fbcount = sblk.b_un.b_fs->e2fs_fbcount;
334 	asblk.b_un.b_fs->e2fs_ficount = sblk.b_un.b_fs->e2fs_ficount;
335 	asblk.b_un.b_fs->e2fs_mtime = sblk.b_un.b_fs->e2fs_mtime;
336 	asblk.b_un.b_fs->e2fs_wtime = sblk.b_un.b_fs->e2fs_wtime;
337 	asblk.b_un.b_fs->e2fs_mnt_count = sblk.b_un.b_fs->e2fs_mnt_count;
338 	asblk.b_un.b_fs->e2fs_max_mnt_count = sblk.b_un.b_fs->e2fs_max_mnt_count;
339 	asblk.b_un.b_fs->e2fs_state = sblk.b_un.b_fs->e2fs_state;
340 	asblk.b_un.b_fs->e2fs_beh = sblk.b_un.b_fs->e2fs_beh;
341 	asblk.b_un.b_fs->e2fs_lastfsck = sblk.b_un.b_fs->e2fs_lastfsck;
342 	asblk.b_un.b_fs->e2fs_fsckintv = sblk.b_un.b_fs->e2fs_fsckintv;
343 	asblk.b_un.b_fs->e2fs_ruid = sblk.b_un.b_fs->e2fs_ruid;
344 	asblk.b_un.b_fs->e2fs_rgid = sblk.b_un.b_fs->e2fs_rgid;
345 	asblk.b_un.b_fs->e2fs_block_group_nr =
346 	    sblk.b_un.b_fs->e2fs_block_group_nr;
347 	asblk.b_un.b_fs->e2fs_features_rocompat &= ~EXT2F_ROCOMPAT_LARGE_FILE;
348 	asblk.b_un.b_fs->e2fs_features_rocompat |=
349 	    sblk.b_un.b_fs->e2fs_features_rocompat & EXT2F_ROCOMPAT_LARGE_FILE;
350 	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
351 	    ((sblock.e2fs.e2fs_features_incompat & ~EXT2F_INCOMPAT_SUPP) ||
352 	    (sblock.e2fs.e2fs_features_rocompat & ~EXT2F_ROCOMPAT_SUPP))) {
353 		if (debug) {
354 			printf("compat 0x%08x, incompat 0x%08x, compat_ro "
355 			    "0x%08x\n",
356 			    sblock.e2fs.e2fs_features_compat,
357 			    sblock.e2fs.e2fs_features_incompat,
358 			    sblock.e2fs.e2fs_features_rocompat);
359 		}
360 		badsb(listerr,"INCOMPATIBLE FEATURE BITS IN SUPER BLOCK");
361 		return 0;
362 	}
363 	if (memcmp(sblk.b_un.b_fs, asblk.b_un.b_fs, SBSIZE)) {
364 		if (debug) {
365 			u_int32_t *nlp, *olp, *endlp;
366 
367 			printf("superblock mismatches\n");
368 			nlp = (u_int32_t *)asblk.b_un.b_fs;
369 			olp = (u_int32_t *)sblk.b_un.b_fs;
370 			endlp = olp + (SBSIZE / sizeof *olp);
371 			for ( ; olp < endlp; olp++, nlp++) {
372 				if (*olp == *nlp)
373 					continue;
374 				printf("offset %ld, original %ld, alternate %ld\n",
375 					(long)(olp - (u_int32_t *)sblk.b_un.b_fs),
376 					(long)letoh32(*olp),
377 					(long)letoh32(*nlp));
378 			}
379 		}
380 		badsb(listerr,
381 		"VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST ALTERNATE");
382 		return (0);
383 	}
384 	havesb = 1;
385 	return (1);
386 }
387 
388 void
389 copyback_sb(struct bufarea *bp)
390 {
391 	/* Copy the in-memory superblock back to buffer */
392 	bp->b_un.b_fs->e2fs_icount = letoh32(sblock.e2fs.e2fs_icount);
393 	bp->b_un.b_fs->e2fs_bcount = letoh32(sblock.e2fs.e2fs_bcount);
394 	bp->b_un.b_fs->e2fs_rbcount = letoh32(sblock.e2fs.e2fs_rbcount);
395 	bp->b_un.b_fs->e2fs_fbcount = letoh32(sblock.e2fs.e2fs_fbcount);
396 	bp->b_un.b_fs->e2fs_ficount = letoh32(sblock.e2fs.e2fs_ficount);
397 	bp->b_un.b_fs->e2fs_first_dblock =
398 					letoh32(sblock.e2fs.e2fs_first_dblock);
399 	bp->b_un.b_fs->e2fs_log_bsize = letoh32(sblock.e2fs.e2fs_log_bsize);
400 	bp->b_un.b_fs->e2fs_log_fsize = letoh32(sblock.e2fs.e2fs_log_fsize);
401 	bp->b_un.b_fs->e2fs_bpg = letoh32(sblock.e2fs.e2fs_bpg);
402 	bp->b_un.b_fs->e2fs_fpg = letoh32(sblock.e2fs.e2fs_fpg);
403 	bp->b_un.b_fs->e2fs_ipg = letoh32(sblock.e2fs.e2fs_ipg);
404 	bp->b_un.b_fs->e2fs_mtime = letoh32(sblock.e2fs.e2fs_mtime);
405 	bp->b_un.b_fs->e2fs_wtime = letoh32(sblock.e2fs.e2fs_wtime);
406 	bp->b_un.b_fs->e2fs_lastfsck = letoh32(sblock.e2fs.e2fs_lastfsck);
407 	bp->b_un.b_fs->e2fs_fsckintv = letoh32(sblock.e2fs.e2fs_fsckintv);
408 	bp->b_un.b_fs->e2fs_creator = letoh32(sblock.e2fs.e2fs_creator);
409 	bp->b_un.b_fs->e2fs_rev = letoh32(sblock.e2fs.e2fs_rev);
410 	bp->b_un.b_fs->e2fs_mnt_count = letoh16(sblock.e2fs.e2fs_mnt_count);
411 	bp->b_un.b_fs->e2fs_max_mnt_count =
412 					letoh16(sblock.e2fs.e2fs_max_mnt_count);
413 	bp->b_un.b_fs->e2fs_magic = letoh16(sblock.e2fs.e2fs_magic);
414 	bp->b_un.b_fs->e2fs_state = letoh16(sblock.e2fs.e2fs_state);
415 	bp->b_un.b_fs->e2fs_beh = letoh16(sblock.e2fs.e2fs_beh);
416 	bp->b_un.b_fs->e2fs_ruid = letoh16(sblock.e2fs.e2fs_ruid);
417 	bp->b_un.b_fs->e2fs_rgid = letoh16(sblock.e2fs.e2fs_rgid);
418 }
419 
420 void
421 badsb(int listerr, char *s)
422 {
423 
424 	if (!listerr)
425 		return;
426 	if (preen)
427 		printf("%s: ", cdevname());
428 	pfatal("BAD SUPER BLOCK: %s\n", s);
429 }
430 
431 /*
432  * Calculate a prototype superblock based on information in the disk label.
433  * When done the cgsblock macro can be calculated and the fs_ncg field
434  * can be used. Do NOT attempt to use other macros without verifying that
435  * their needed information is available!
436  */
437 int
438 calcsb(char *dev, int devfd, struct m_ext2fs *fs, struct disklabel *lp)
439 {
440 	struct partition *pp;
441 	char *cp;
442 
443 	cp = strchr(dev, '\0');
444 	if ((cp == NULL || (cp[-1] < 'a' || cp[-1] >= 'a' + MAXPARTITIONS)) &&
445 	    !isdigit((unsigned char)cp[-1])) {
446 		pfatal("%s: CANNOT FIGURE OUT FILE SYSTEM PARTITION\n", dev);
447 		return (0);
448 	}
449 	cp--;
450 	if (lp == NULL)
451 		pfatal("%s: CANNOT READ DISKLABEL\n", dev);
452 	if (isdigit((unsigned char)*cp))
453 		pp = &lp->d_partitions[0];
454 	else
455 		pp = &lp->d_partitions[*cp - 'a'];
456 	if (pp->p_fstype != FS_EXT2FS) {
457 		pfatal("%s: NOT LABELED AS A EXT2 FILE SYSTEM (%s)\n",
458 			dev, pp->p_fstype < FSMAXTYPES ?
459 			fstypenames[pp->p_fstype] : "unknown");
460 		return (0);
461 	}
462 	memset(fs, 0, sizeof(struct m_ext2fs));
463 	fs->e2fs_bsize = DISKLABELV1_FFS_FSIZE(pp->p_fragblock); /* XXX */
464 	if (fs->e2fs_bsize == 0) {
465 		pfatal("%s: BLOCK SIZE DETERMINED TO BE ZERO\n", dev);
466 		return (0);
467 	}
468 	fs->e2fs.e2fs_log_bsize = fs->e2fs_bsize / 1024;
469 	fs->e2fs.e2fs_bcount = (pp->p_size * DEV_BSIZE) / fs->e2fs_bsize;
470 	fs->e2fs.e2fs_first_dblock = (fs->e2fs.e2fs_log_bsize == 0) ? 1 : 0;
471 	fs->e2fs.e2fs_bpg = fs->e2fs_bsize * NBBY;
472 	fs->e2fs_bshift = LOG_MINBSIZE + fs->e2fs.e2fs_log_bsize;
473 	fs->e2fs_qbmask = fs->e2fs_bsize - 1;
474 	fs->e2fs_bmask = ~fs->e2fs_qbmask;
475 	fs->e2fs_ncg =
476 		howmany(fs->e2fs.e2fs_bcount - fs->e2fs.e2fs_first_dblock,
477 		fs->e2fs.e2fs_bpg);
478 	fs->e2fs_fsbtodb = fs->e2fs.e2fs_log_bsize + 1;
479 	fs->e2fs_ngdb = howmany(fs->e2fs_ncg,
480 		fs->e2fs_bsize / sizeof(struct ext2_gd));
481 
482 	return (1);
483 }
484 
485 static struct disklabel *
486 getdisklabel(char *s, int fd)
487 {
488 	static struct disklabel lab;
489 
490 	if (ioctl(fd, DIOCGDINFO, (char *)&lab) == -1) {
491 		if (s == NULL)
492 			return (NULL);
493 		pwarn("ioctl (GCINFO): %s\n", strerror(errno));
494 		errexit("%s: can't read disk label\n", s);
495 	}
496 	return (&lab);
497 }
498 
499 daddr32_t
500 cgoverhead(int c)
501 {
502 	int overh;
503 	overh =	1 /* block bitmap */ +
504 		1 /* inode bitmap */ +
505 		sblock.e2fs_itpg;
506 	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
507 	    sblock.e2fs.e2fs_features_rocompat & EXT2F_ROCOMPAT_SPARSE_SUPER) {
508 		if (cg_has_sb(c) == 0)
509 			return overh;
510 	}
511 	overh += 1 + sblock.e2fs_ngdb;
512 	return overh;
513 }
514