xref: /netbsd-src/sbin/fsck_ext2fs/setup.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: setup.c,v 1.16 2004/10/29 17:37:30 dsl Exp $	*/
2 
3 /*
4  * Copyright (c) 1980, 1986, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *	notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *	notice, this list of conditions and the following disclaimer in the
14  *	documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *	may be used to endorse or promote products derived from this software
17  *	without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 /*
33  * Copyright (c) 1997 Manuel Bouyer.
34  *
35  * Redistribution and use in source and binary forms, with or without
36  * modification, are permitted provided that the following conditions
37  * are met:
38  * 1. Redistributions of source code must retain the above copyright
39  *	notice, this list of conditions and the following disclaimer.
40  * 2. Redistributions in binary form must reproduce the above copyright
41  *	notice, this list of conditions and the following disclaimer in the
42  *	documentation and/or other materials provided with the distribution.
43  * 3. All advertising materials mentioning features or use of this software
44  *	must display the following acknowledgement:
45  *	This product includes software developed by Manuel Bouyer.
46  * 4. The name of the author may not be used to endorse or promote products
47  *    derived from this software without specific prior written permission.
48  *
49  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
50  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
51  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
52  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
53  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
54  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
55  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
56  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
57  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
58  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
59  */
60 
61 #include <sys/cdefs.h>
62 #ifndef lint
63 #if 0
64 static char sccsid[] = "@(#)setup.c	8.5 (Berkeley) 11/23/94";
65 #else
66 __RCSID("$NetBSD: setup.c,v 1.16 2004/10/29 17:37:30 dsl Exp $");
67 #endif
68 #endif /* not lint */
69 
70 #define FSTYPENAMES
71 #include <sys/param.h>
72 #include <sys/time.h>
73 #include <ufs/ext2fs/ext2fs_dinode.h>
74 #include <ufs/ext2fs/ext2fs.h>
75 #include <sys/stat.h>
76 #include <sys/ioctl.h>
77 #include <sys/disklabel.h>
78 #include <sys/file.h>
79 
80 #include <errno.h>
81 #include <stdio.h>
82 #include <stdlib.h>
83 #include <string.h>
84 #include <ctype.h>
85 
86 #include "fsck.h"
87 #include "extern.h"
88 #include "fsutil.h"
89 
90 #define POWEROF2(num)	(((num) & ((num) - 1)) == 0)
91 
92 void badsb __P((int, char *));
93 int calcsb __P((const char *, int, struct m_ext2fs *));
94 static struct disklabel *getdisklabel __P((const char *, int));
95 static int readsb __P((int));
96 
97 int
98 setup(dev)
99 	const char *dev;
100 {
101 	long cg, asked, i;
102 	long bmapsize;
103 	struct disklabel *lp;
104 	off_t sizepb;
105 	struct stat statb;
106 	struct m_ext2fs proto;
107 	int doskipclean;
108 	u_int64_t maxfilesize;
109 
110 	havesb = 0;
111 	fswritefd = -1;
112 	doskipclean = skipclean;
113 	if (stat(dev, &statb) < 0) {
114 		printf("Can't stat %s: %s\n", dev, strerror(errno));
115 		return (0);
116 	}
117 	if (!S_ISCHR(statb.st_mode)) {
118 		pfatal("%s is not a character device", dev);
119 		if (reply("CONTINUE") == 0)
120 			return (0);
121 	}
122 	if ((fsreadfd = open(dev, O_RDONLY)) < 0) {
123 		printf("Can't open %s: %s\n", dev, strerror(errno));
124 		return (0);
125 	}
126 	if (preen == 0)
127 		printf("** %s", dev);
128 	if (nflag || (fswritefd = open(dev, O_WRONLY)) < 0) {
129 		fswritefd = -1;
130 		if (preen)
131 			pfatal("NO WRITE ACCESS");
132 		printf(" (NO WRITE)");
133 	}
134 	if (preen == 0)
135 		printf("\n");
136 	fsmodified = 0;
137 	lfdir = 0;
138 	initbarea(&sblk);
139 	initbarea(&asblk);
140 	sblk.b_un.b_buf = malloc(SBSIZE);
141 	asblk.b_un.b_buf = malloc(SBSIZE);
142 	if (sblk.b_un.b_buf == NULL || asblk.b_un.b_buf == NULL)
143 		errexit("cannot allocate space for superblock\n");
144 	if ((lp = getdisklabel((char *)NULL, fsreadfd)) != NULL)
145 		dev_bsize = secsize = lp->d_secsize;
146 	else
147 		dev_bsize = secsize = DEV_BSIZE;
148 	/*
149 	 * Read in the superblock, looking for alternates if necessary
150 	 */
151 	if (readsb(1) == 0) {
152 		if (bflag || preen || calcsb(dev, fsreadfd, &proto) == 0)
153 			return(0);
154 		if (reply("LOOK FOR ALTERNATE SUPERBLOCKS") == 0)
155 			return (0);
156 		for (cg = 1; cg < proto.e2fs_ncg; cg++) {
157 			bflag = fsbtodb(&proto,
158 				cg * proto.e2fs.e2fs_bpg + proto.e2fs.e2fs_first_dblock);
159 			if (readsb(0) != 0)
160 				break;
161 		}
162 		if (cg >= proto.e2fs_ncg) {
163 			printf("%s %s\n%s %s\n%s %s\n",
164 				"SEARCH FOR ALTERNATE SUPER-BLOCK",
165 				"FAILED. YOU MUST USE THE",
166 				"-b OPTION TO FSCK_FFS TO SPECIFY THE",
167 				"LOCATION OF AN ALTERNATE",
168 				"SUPER-BLOCK TO SUPPLY NEEDED",
169 				"INFORMATION; SEE fsck_ext2fs(8).");
170 			return(0);
171 		}
172 		doskipclean = 0;
173 		pwarn("USING ALTERNATE SUPERBLOCK AT %d\n", bflag);
174 	}
175 	if (debug)
176 		printf("state = %d\n", sblock.e2fs.e2fs_state);
177 	if (sblock.e2fs.e2fs_state == E2FS_ISCLEAN) {
178 		if (doskipclean) {
179 			pwarn("%sile system is clean; not checking\n",
180 				preen ? "f" : "** F");
181 			return (-1);
182 		}
183 		if (!preen)
184 			pwarn("** File system is already clean\n");
185 	}
186 	maxfsblock = sblock.e2fs.e2fs_bcount;
187 	maxino = sblock.e2fs_ncg * sblock.e2fs.e2fs_ipg;
188 	sizepb = sblock.e2fs_bsize;
189 	maxfilesize = sblock.e2fs_bsize * NDADDR - 1;
190 	for (i = 0; i < NIADDR; i++) {
191 		sizepb *= NINDIR(&sblock);
192 		maxfilesize += sizepb;
193 	}
194 	/*
195 	 * Check and potentially fix certain fields in the super block.
196 	 */
197 	if ((sblock.e2fs.e2fs_rbcount < 0) ||
198 			(sblock.e2fs.e2fs_rbcount > sblock.e2fs.e2fs_bcount)) {
199 		pfatal("IMPOSSIBLE RESERVED BLOCK COUNT=%d IN SUPERBLOCK",
200 			sblock.e2fs.e2fs_rbcount);
201 		if (reply("SET TO DEFAULT") == 1) {
202 			sblock.e2fs.e2fs_rbcount = sblock.e2fs.e2fs_bcount * 0.1;
203 			sbdirty();
204 			dirty(&asblk);
205 		}
206 	}
207 	if (sblock.e2fs.e2fs_bpg != sblock.e2fs.e2fs_fpg) {
208 		pfatal("WRONG FPG=%d (BPG=%d) IN SUPERBLOCK",
209 			sblock.e2fs.e2fs_fpg, sblock.e2fs.e2fs_bpg);
210 		return 0;
211 	}
212 	if (asblk.b_dirty && !bflag) {
213 		copyback_sb(&asblk);
214 		flush(fswritefd, &asblk);
215 	}
216 	/*
217 	 * read in the summary info.
218 	 */
219 
220 	sblock.e2fs_gd = malloc(sblock.e2fs_ngdb * sblock.e2fs_bsize);
221 	if (sblock.e2fs_gd == NULL)
222 		errexit("out of memory\n");
223 	asked = 0;
224 	for (i=0; i < sblock.e2fs_ngdb; i++) {
225 		if (bread(fsreadfd,(char *)
226 			&sblock.e2fs_gd[i* sblock.e2fs_bsize / sizeof(struct ext2_gd)],
227 			fsbtodb(&sblock, ((sblock.e2fs_bsize>1024)?0:1)+i+1),
228 			sblock.e2fs_bsize) != 0 && !asked) {
229 			pfatal("BAD SUMMARY INFORMATION");
230 			if (reply("CONTINUE") == 0)
231 				errexit("%s\n", "");
232 			asked++;
233 		}
234 	}
235 	/*
236 	 * allocate and initialize the necessary maps
237 	 */
238 	bmapsize = roundup(howmany(maxfsblock, NBBY), sizeof(int16_t));
239 	blockmap = calloc((unsigned)bmapsize, sizeof (char));
240 	if (blockmap == NULL) {
241 		printf("cannot alloc %u bytes for blockmap\n",
242 			(unsigned)bmapsize);
243 		goto badsblabel;
244 	}
245 	statemap = calloc((unsigned)(maxino + 2), sizeof(char));
246 	if (statemap == NULL) {
247 		printf("cannot alloc %u bytes for statemap\n",
248 			(unsigned)(maxino + 1));
249 		goto badsblabel;
250 	}
251 	typemap = calloc((unsigned)(maxino + 1), sizeof(char));
252 	if (typemap == NULL) {
253 		printf("cannot alloc %u bytes for typemap\n",
254 		    (unsigned)(maxino + 1));
255 		goto badsblabel;
256 	}
257 	lncntp = (int16_t *)calloc((unsigned)(maxino + 1), sizeof(int16_t));
258 	if (lncntp == NULL) {
259 		printf("cannot alloc %u bytes for lncntp\n",
260 			(unsigned)((maxino + 1) * sizeof(int16_t)));
261 		goto badsblabel;
262 	}
263 	for (numdirs = 0, cg = 0; cg < sblock.e2fs_ncg; cg++) {
264 		numdirs += fs2h16(sblock.e2fs_gd[cg].ext2bgd_ndirs);
265 	}
266 	inplast = 0;
267 	listmax = numdirs + 10;
268 	inpsort = (struct inoinfo **)calloc((unsigned)listmax,
269 		sizeof(struct inoinfo *));
270 	inphead = (struct inoinfo **)calloc((unsigned)numdirs,
271 		sizeof(struct inoinfo *));
272 	if (inpsort == NULL || inphead == NULL) {
273 		printf("cannot alloc %u bytes for inphead\n",
274 			(unsigned)(numdirs * sizeof(struct inoinfo *)));
275 		goto badsblabel;
276 	}
277 	bufinit();
278 	return (1);
279 
280 badsblabel:
281 	ckfini(0);
282 	return (0);
283 }
284 
285 /*
286  * Read in the super block and its summary info, convert to host byte order.
287  */
288 static int
289 readsb(listerr)
290 	int listerr;
291 {
292 	daddr_t super = bflag ? bflag : SBOFF / dev_bsize;
293 
294 	if (bread(fsreadfd, (char *)sblk.b_un.b_fs, super, (long)SBSIZE) != 0)
295 		return (0);
296 	sblk.b_bno = super;
297 	sblk.b_size = SBSIZE;
298 
299 	/* Copy the superblock in memory */
300 	e2fs_sbload(sblk.b_un.b_fs, &sblock.e2fs);
301 
302 	/*
303 	 * run a few consistency checks of the super block
304 	 */
305 	if (sblock.e2fs.e2fs_magic != E2FS_MAGIC) {
306 		badsb(listerr, "MAGIC NUMBER WRONG"); return (0);
307 	}
308 	if (sblock.e2fs.e2fs_log_bsize > 2) {
309 		badsb(listerr, "BAD LOG_BSIZE"); return (0);
310 	}
311 
312 	/* compute the dynamic fields of the in-memory sb */
313 	/* compute dynamic sb infos */
314 	sblock.e2fs_ncg =
315 		howmany(sblock.e2fs.e2fs_bcount - sblock.e2fs.e2fs_first_dblock,
316 		sblock.e2fs.e2fs_bpg);
317 	/* XXX assume hw bsize = 512 */
318 	sblock.e2fs_fsbtodb = sblock.e2fs.e2fs_log_bsize + 1;
319 	sblock.e2fs_bsize = 1024 << sblock.e2fs.e2fs_log_bsize;
320 	sblock.e2fs_bshift = LOG_MINBSIZE + sblock.e2fs.e2fs_log_bsize;
321 	sblock.e2fs_qbmask = sblock.e2fs_bsize - 1;
322 	sblock.e2fs_bmask = ~sblock.e2fs_qbmask;
323 	sblock.e2fs_ngdb = howmany(sblock.e2fs_ncg,
324 		sblock.e2fs_bsize / sizeof(struct ext2_gd));
325 	sblock.e2fs_ipb = sblock.e2fs_bsize / sizeof(struct ext2fs_dinode);
326 	sblock.e2fs_itpg = sblock.e2fs.e2fs_ipg/sblock.e2fs_ipb;
327 
328 	/*
329 	 * Compute block size that the filesystem is based on,
330 	 * according to fsbtodb, and adjust superblock block number
331 	 * so we can tell if this is an alternate later.
332 	 */
333 	super *= dev_bsize;
334 	dev_bsize = sblock.e2fs_bsize / fsbtodb(&sblock, 1);
335 	sblk.b_bno = super / dev_bsize;
336 
337 	getblk(&asblk, 1 * sblock.e2fs.e2fs_bpg + sblock.e2fs.e2fs_first_dblock,
338 		(long)SBSIZE);
339 	if (asblk.b_errs)
340 		return (0);
341 	if (bflag) {
342 		havesb = 1;
343 		return (1);
344 	}
345 
346 	/*
347 	 * Set all possible fields that could differ, then do check
348 	 * of whole super block against an alternate super block.
349 	 * When an alternate super-block is specified this check is skipped.
350 	 */
351 	asblk.b_un.b_fs->e2fs_rbcount = sblk.b_un.b_fs->e2fs_rbcount;
352 	asblk.b_un.b_fs->e2fs_fbcount = sblk.b_un.b_fs->e2fs_fbcount;
353 	asblk.b_un.b_fs->e2fs_ficount = sblk.b_un.b_fs->e2fs_ficount;
354 	asblk.b_un.b_fs->e2fs_mtime = sblk.b_un.b_fs->e2fs_mtime;
355 	asblk.b_un.b_fs->e2fs_wtime = sblk.b_un.b_fs->e2fs_wtime;
356 	asblk.b_un.b_fs->e2fs_mnt_count = sblk.b_un.b_fs->e2fs_mnt_count;
357 	asblk.b_un.b_fs->e2fs_max_mnt_count = sblk.b_un.b_fs->e2fs_max_mnt_count;
358 	asblk.b_un.b_fs->e2fs_state = sblk.b_un.b_fs->e2fs_state;
359 	asblk.b_un.b_fs->e2fs_beh = sblk.b_un.b_fs->e2fs_beh;
360 	asblk.b_un.b_fs->e2fs_lastfsck = sblk.b_un.b_fs->e2fs_lastfsck;
361 	asblk.b_un.b_fs->e2fs_fsckintv = sblk.b_un.b_fs->e2fs_fsckintv;
362 	asblk.b_un.b_fs->e2fs_ruid = sblk.b_un.b_fs->e2fs_ruid;
363 	asblk.b_un.b_fs->e2fs_rgid = sblk.b_un.b_fs->e2fs_rgid;
364 	asblk.b_un.b_fs->e2fs_block_group_nr =
365 	    sblk.b_un.b_fs->e2fs_block_group_nr;
366 	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
367 	    ((sblock.e2fs.e2fs_features_incompat & ~EXT2F_INCOMPAT_SUPP) ||
368 	    (sblock.e2fs.e2fs_features_rocompat & ~EXT2F_ROCOMPAT_SUPP))) {
369 		if (debug) {
370 			printf("compat 0x%08x, incompat 0x%08x, compat_ro "
371 			    "0x%08x\n",
372 			    sblock.e2fs.e2fs_features_compat,
373 			    sblock.e2fs.e2fs_features_incompat,
374 			    sblock.e2fs.e2fs_features_rocompat);
375 		}
376 		badsb(listerr,"INCOMPATIBLE FEATURE BITS IN SUPER BLOCK");
377 		return 0;
378 	}
379 	if (memcmp(sblk.b_un.b_fs, asblk.b_un.b_fs, SBSIZE)) {
380 		if (debug) {
381 			u_int32_t *nlp, *olp, *endlp;
382 
383 			printf("superblock mismatches\n");
384 			nlp = (u_int32_t *)asblk.b_un.b_fs;
385 			olp = (u_int32_t *)sblk.b_un.b_fs;
386 			endlp = olp + (SBSIZE / sizeof *olp);
387 			for ( ; olp < endlp; olp++, nlp++) {
388 				if (*olp == *nlp)
389 					continue;
390 				printf("offset %ld, original %ld, alternate %ld\n",
391 					(long)(olp - (u_int32_t *)sblk.b_un.b_fs),
392 					(long)fs2h32(*olp),
393 					(long)fs2h32(*nlp));
394 			}
395 		}
396 		badsb(listerr,
397 		"VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST ALTERNATE");
398 		return (0);
399 	}
400 	havesb = 1;
401 	return (1);
402 }
403 
404 void
405 copyback_sb(bp)
406 	struct bufarea *bp;
407 {
408 	/* Copy the in-memory superblock back to buffer */
409 	bp->b_un.b_fs->e2fs_icount = fs2h32(sblock.e2fs.e2fs_icount);
410 	bp->b_un.b_fs->e2fs_bcount = fs2h32(sblock.e2fs.e2fs_bcount);
411 	bp->b_un.b_fs->e2fs_rbcount = fs2h32(sblock.e2fs.e2fs_rbcount);
412 	bp->b_un.b_fs->e2fs_fbcount = fs2h32(sblock.e2fs.e2fs_fbcount);
413 	bp->b_un.b_fs->e2fs_ficount = fs2h32(sblock.e2fs.e2fs_ficount);
414 	bp->b_un.b_fs->e2fs_first_dblock =
415 					fs2h32(sblock.e2fs.e2fs_first_dblock);
416 	bp->b_un.b_fs->e2fs_log_bsize = fs2h32(sblock.e2fs.e2fs_log_bsize);
417 	bp->b_un.b_fs->e2fs_fsize = fs2h32(sblock.e2fs.e2fs_fsize);
418 	bp->b_un.b_fs->e2fs_bpg = fs2h32(sblock.e2fs.e2fs_bpg);
419 	bp->b_un.b_fs->e2fs_fpg = fs2h32(sblock.e2fs.e2fs_fpg);
420 	bp->b_un.b_fs->e2fs_ipg = fs2h32(sblock.e2fs.e2fs_ipg);
421 	bp->b_un.b_fs->e2fs_mtime = fs2h32(sblock.e2fs.e2fs_mtime);
422 	bp->b_un.b_fs->e2fs_wtime = fs2h32(sblock.e2fs.e2fs_wtime);
423 	bp->b_un.b_fs->e2fs_lastfsck = fs2h32(sblock.e2fs.e2fs_lastfsck);
424 	bp->b_un.b_fs->e2fs_fsckintv = fs2h32(sblock.e2fs.e2fs_fsckintv);
425 	bp->b_un.b_fs->e2fs_creator = fs2h32(sblock.e2fs.e2fs_creator);
426 	bp->b_un.b_fs->e2fs_rev = fs2h32(sblock.e2fs.e2fs_rev);
427 	bp->b_un.b_fs->e2fs_mnt_count = fs2h16(sblock.e2fs.e2fs_mnt_count);
428 	bp->b_un.b_fs->e2fs_max_mnt_count =
429 					fs2h16(sblock.e2fs.e2fs_max_mnt_count);
430 	bp->b_un.b_fs->e2fs_magic = fs2h16(sblock.e2fs.e2fs_magic);
431 	bp->b_un.b_fs->e2fs_state = fs2h16(sblock.e2fs.e2fs_state);
432 	bp->b_un.b_fs->e2fs_beh = fs2h16(sblock.e2fs.e2fs_beh);
433 	bp->b_un.b_fs->e2fs_ruid = fs2h16(sblock.e2fs.e2fs_ruid);
434 	bp->b_un.b_fs->e2fs_rgid = fs2h16(sblock.e2fs.e2fs_rgid);
435 }
436 
437 void
438 badsb(listerr, s)
439 	int listerr;
440 	char *s;
441 {
442 
443 	if (!listerr)
444 		return;
445 	if (preen)
446 		printf("%s: ", cdevname());
447 	pfatal("BAD SUPER BLOCK: %s\n", s);
448 }
449 
450 /*
451  * Calculate a prototype superblock based on information in the disk label.
452  * When done the cgsblock macro can be calculated and the fs_ncg field
453  * can be used. Do NOT attempt to use other macros without verifying that
454  * their needed information is available!
455  */
456 
457 int
458 calcsb(dev, devfd, fs)
459 	const char *dev;
460 	int devfd;
461 	struct m_ext2fs *fs;
462 {
463 	struct disklabel *lp;
464 	struct partition *pp;
465 	char *cp;
466 
467 	cp = strchr(dev, '\0');
468 	if (cp-- == dev ||
469 	    ((*cp < 'a' || *cp > 'h') && !isdigit((unsigned char)*cp))) {
470 		pfatal("%s: CANNOT FIGURE OUT FILE SYSTEM PARTITION\n", dev);
471 		return (0);
472 	}
473 	lp = getdisklabel(dev, devfd);
474 	if (isdigit((unsigned char)*cp))
475 		pp = &lp->d_partitions[0];
476 	else
477 		pp = &lp->d_partitions[*cp - 'a'];
478 	if (pp->p_fstype != FS_EX2FS) {
479 		pfatal("%s: NOT LABELED AS A EXT2 FILE SYSTEM (%s)\n",
480 			dev, pp->p_fstype < FSMAXTYPES ?
481 			fstypenames[pp->p_fstype] : "unknown");
482 		return (0);
483 	}
484 	memset(fs, 0, sizeof(struct m_ext2fs));
485 	fs->e2fs_bsize = pp->p_fsize;
486 	fs->e2fs.e2fs_log_bsize = pp->p_fsize / 1024;
487 	fs->e2fs.e2fs_bcount = (pp->p_size * DEV_BSIZE) / fs->e2fs_bsize;
488 	fs->e2fs.e2fs_first_dblock = (fs->e2fs.e2fs_log_bsize == 0) ? 1 : 0;
489 	fs->e2fs.e2fs_bpg = fs->e2fs_bsize * NBBY;
490 	fs->e2fs_bshift = LOG_MINBSIZE + fs->e2fs.e2fs_log_bsize;
491 	fs->e2fs_qbmask = fs->e2fs_bsize - 1;
492 	fs->e2fs_bmask = ~fs->e2fs_qbmask;
493 	fs->e2fs_ncg =
494 		howmany(fs->e2fs.e2fs_bcount - fs->e2fs.e2fs_first_dblock,
495 		fs->e2fs.e2fs_bpg);
496 	fs->e2fs_fsbtodb = fs->e2fs.e2fs_log_bsize + 1;
497 	fs->e2fs_ngdb = howmany(fs->e2fs_ncg,
498 		fs->e2fs_bsize / sizeof(struct ext2_gd));
499 
500 	return (1);
501 }
502 
503 static struct disklabel *
504 getdisklabel(s, fd)
505 	const char *s;
506 	int	fd;
507 {
508 	static struct disklabel lab;
509 
510 	if (ioctl(fd, DIOCGDINFO, (char *)&lab) < 0) {
511 		if (s == NULL)
512 			return ((struct disklabel *)NULL);
513 		pwarn("ioctl (GCINFO): %s\n", strerror(errno));
514 		errexit("%s: can't read disk label\n", s);
515 	}
516 	return (&lab);
517 }
518 
519 daddr_t
520 cgoverhead(c)
521 	int c;
522 {
523 	int overh;
524 	overh =	1 /* block bitmap */ +
525 		1 /* inode bitmap */ +
526 		sblock.e2fs_itpg;
527 	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
528 	    sblock.e2fs.e2fs_features_rocompat & EXT2F_ROCOMPAT_SPARSESUPER) {
529 		if (cg_has_sb(c) == 0)
530 			return overh;
531 	}
532 	overh += 1 + sblock.e2fs_ngdb;
533 	return overh;
534 }
535