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setup.c revision 1.25.6.1
      1 /*	$NetBSD: setup.c,v 1.25.6.1 2011/01/16 12:38:27 bouyer 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 1.25.6.1 2011/01/16 12:38:27 bouyer 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 #include "exitvalues.h"
     90 
     91 void badsb(int, const char *);
     92 int calcsb(const char *, int, struct m_ext2fs *);
     93 static struct disklabel *getdisklabel(const char *, int);
     94 static int readsb(int);
     95 
     96 int
     97 setup(const char *dev)
     98 {
     99 	long cg, asked, i;
    100 	long bmapsize;
    101 	struct disklabel *lp;
    102 	off_t sizepb;
    103 	struct stat statb;
    104 	struct m_ext2fs proto;
    105 	int doskipclean;
    106 	u_int64_t maxfilesize;
    107 
    108 	havesb = 0;
    109 	fswritefd = -1;
    110 	doskipclean = skipclean;
    111 	if (stat(dev, &statb) < 0) {
    112 		printf("Can't stat %s: %s\n", dev, strerror(errno));
    113 		return 0;
    114 	}
    115 	if (!S_ISCHR(statb.st_mode)) {
    116 		pfatal("%s is not a character device", dev);
    117 		if (reply("CONTINUE") == 0)
    118 			return 0;
    119 	}
    120 	if ((fsreadfd = open(dev, O_RDONLY)) < 0) {
    121 		printf("Can't open %s: %s\n", dev, strerror(errno));
    122 		return 0;
    123 	}
    124 	if (preen == 0)
    125 		printf("** %s", dev);
    126 	if (nflag || (fswritefd = open(dev, O_WRONLY)) < 0) {
    127 		fswritefd = -1;
    128 		if (preen)
    129 			pfatal("NO WRITE ACCESS");
    130 		printf(" (NO WRITE)");
    131 	}
    132 	if (preen == 0)
    133 		printf("\n");
    134 	fsmodified = 0;
    135 	lfdir = 0;
    136 	initbarea(&sblk);
    137 	initbarea(&asblk);
    138 	sblk.b_un.b_buf = malloc(SBSIZE);
    139 	asblk.b_un.b_buf = malloc(SBSIZE);
    140 	if (sblk.b_un.b_buf == NULL || asblk.b_un.b_buf == NULL)
    141 		errexit("cannot allocate space for superblock");
    142 	if ((lp = getdisklabel((char *)NULL, fsreadfd)) != NULL)
    143 		dev_bsize = secsize = lp->d_secsize;
    144 	else
    145 		dev_bsize = secsize = DEV_BSIZE;
    146 	/*
    147 	 * Read in the superblock, looking for alternates if necessary
    148 	 */
    149 	if (readsb(1) == 0) {
    150 		if (bflag || preen || calcsb(dev, fsreadfd, &proto) == 0)
    151 			return 0;
    152 		if (reply("LOOK FOR ALTERNATE SUPERBLOCKS") == 0)
    153 			return 0;
    154 		for (cg = 1; cg < proto.e2fs_ncg; cg++) {
    155 			bflag = fsbtodb(&proto,
    156 			    cg * proto.e2fs.e2fs_bpg +
    157 			    proto.e2fs.e2fs_first_dblock);
    158 			if (readsb(0) != 0)
    159 				break;
    160 		}
    161 		if (cg >= proto.e2fs_ncg) {
    162 			printf("%s %s\n%s %s\n%s %s\n",
    163 			    "SEARCH FOR ALTERNATE SUPER-BLOCK",
    164 			    "FAILED. YOU MUST USE THE",
    165 			    "-b OPTION TO FSCK_FFS TO SPECIFY THE",
    166 			    "LOCATION OF AN ALTERNATE",
    167 			    "SUPER-BLOCK TO SUPPLY NEEDED",
    168 			    "INFORMATION; SEE fsck_ext2fs(8).");
    169 			return 0;
    170 		}
    171 		doskipclean = 0;
    172 		pwarn("USING ALTERNATE SUPERBLOCK AT %d\n", bflag);
    173 	}
    174 	if (debug)
    175 		printf("state = %d\n", sblock.e2fs.e2fs_state);
    176 	if (sblock.e2fs.e2fs_state == E2FS_ISCLEAN) {
    177 		if (doskipclean) {
    178 			pwarn("%sile system is clean; not checking\n",
    179 			    preen ? "f" : "** F");
    180 			return -1;
    181 		}
    182 		if (!preen)
    183 			pwarn("** File system is already clean\n");
    184 	}
    185 	maxfsblock = sblock.e2fs.e2fs_bcount;
    186 	maxino = sblock.e2fs_ncg * sblock.e2fs.e2fs_ipg;
    187 	sizepb = sblock.e2fs_bsize;
    188 	maxfilesize = sblock.e2fs_bsize * NDADDR - 1;
    189 	for (i = 0; i < NIADDR; i++) {
    190 		sizepb *= NINDIR(&sblock);
    191 		maxfilesize += sizepb;
    192 	}
    193 	/*
    194 	 * Check and potentially fix certain fields in the super block.
    195 	 */
    196 	if (/* (sblock.e2fs.e2fs_rbcount < 0) || */
    197 	    (sblock.e2fs.e2fs_rbcount > sblock.e2fs.e2fs_bcount)) {
    198 		pfatal("IMPOSSIBLE RESERVED BLOCK COUNT=%d IN SUPERBLOCK",
    199 		    sblock.e2fs.e2fs_rbcount);
    200 		if (reply("SET TO DEFAULT") == 1) {
    201 			sblock.e2fs.e2fs_rbcount =
    202 			    sblock.e2fs.e2fs_bcount * MINFREE / 100;
    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");
    223 	asked = 0;
    224 	for (i = 0; i < sblock.e2fs_ngdb; i++) {
    225 		if (bread(fsreadfd,
    226 		    (char *)&sblock.e2fs_gd[i * sblock.e2fs_bsize /
    227 		    sizeof(struct ext2_gd)],
    228 		    fsbtodb(&sblock, ((sblock.e2fs_bsize > 1024) ? 0 : 1) +
    229 		    i + 1),
    230 		    sblock.e2fs_bsize) != 0 && !asked) {
    231 			pfatal("BAD SUMMARY INFORMATION");
    232 			if (reply("CONTINUE") == 0)
    233 				exit(FSCK_EXIT_CHECK_FAILED);
    234 			asked++;
    235 		}
    236 	}
    237 	/*
    238 	 * allocate and initialize the necessary maps
    239 	 */
    240 	bmapsize = roundup(howmany(maxfsblock, NBBY), sizeof(int16_t));
    241 	blockmap = calloc((unsigned int)bmapsize, sizeof(char));
    242 	if (blockmap == NULL) {
    243 		printf("cannot alloc %u bytes for blockmap\n",
    244 		    (unsigned int)bmapsize);
    245 		goto badsblabel;
    246 	}
    247 	statemap = calloc((unsigned int)(maxino + 2), sizeof(char));
    248 	if (statemap == NULL) {
    249 		printf("cannot alloc %u bytes for statemap\n",
    250 		    (unsigned int)(maxino + 1));
    251 		goto badsblabel;
    252 	}
    253 	typemap = calloc((unsigned int)(maxino + 1), sizeof(char));
    254 	if (typemap == NULL) {
    255 		printf("cannot alloc %u bytes for typemap\n",
    256 		    (unsigned int)(maxino + 1));
    257 		goto badsblabel;
    258 	}
    259 	lncntp = calloc((unsigned)(maxino + 1), sizeof(int16_t));
    260 	if (lncntp == NULL) {
    261 		printf("cannot alloc %u bytes for lncntp\n",
    262 		    (unsigned int)((maxino + 1) * sizeof(int16_t)));
    263 		goto badsblabel;
    264 	}
    265 	for (numdirs = 0, cg = 0; cg < sblock.e2fs_ncg; cg++) {
    266 		numdirs += fs2h16(sblock.e2fs_gd[cg].ext2bgd_ndirs);
    267 	}
    268 	inplast = 0;
    269 	listmax = numdirs + 10;
    270 	inpsort = calloc((unsigned int)listmax, sizeof(struct inoinfo *));
    271 	inphead = calloc((unsigned int)numdirs, sizeof(struct inoinfo *));
    272 	if (inpsort == NULL || inphead == NULL) {
    273 		printf("cannot alloc %u bytes for inphead\n",
    274 		    (unsigned int)(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(int listerr)
    290 {
    291 	daddr_t super = bflag ? bflag : SBOFF / dev_bsize;
    292 
    293 	if (bread(fsreadfd, (char *)sblk.b_un.b_fs, super, (long)SBSIZE) != 0)
    294 		return 0;
    295 	sblk.b_bno = super;
    296 	sblk.b_size = SBSIZE;
    297 
    298 	/* Copy the superblock in memory */
    299 	e2fs_sbload(sblk.b_un.b_fs, &sblock.e2fs);
    300 
    301 	/*
    302 	 * run a few consistency checks of the super block
    303 	 */
    304 	if (sblock.e2fs.e2fs_magic != E2FS_MAGIC) {
    305 		badsb(listerr, "MAGIC NUMBER WRONG");
    306 		return 0;
    307 	}
    308 	if (sblock.e2fs.e2fs_log_bsize > 2) {
    309 		badsb(listerr, "BAD LOG_BSIZE");
    310 		return 0;
    311 	}
    312 	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
    313 	    (!powerof2(sblock.e2fs.e2fs_inode_size) ||
    314 	     sblock.e2fs.e2fs_inode_size < sizeof(struct ext2fs_dinode) ||
    315 	     sblock.e2fs.e2fs_inode_size >
    316 	      (1024 << sblock.e2fs.e2fs_log_bsize))) {
    317 		badsb(listerr, "BAD INODE_SIZE");
    318 		return 0;
    319 	}
    320 
    321 	/* compute the dynamic fields of the in-memory sb */
    322 	/* compute dynamic sb infos */
    323 	sblock.e2fs_ncg =
    324 	    howmany(sblock.e2fs.e2fs_bcount - sblock.e2fs.e2fs_first_dblock,
    325 	    sblock.e2fs.e2fs_bpg);
    326 	/* XXX assume hw bsize = 512 */
    327 	sblock.e2fs_fsbtodb = sblock.e2fs.e2fs_log_bsize + 1;
    328 	sblock.e2fs_bsize = 1024 << sblock.e2fs.e2fs_log_bsize;
    329 	sblock.e2fs_bshift = LOG_MINBSIZE + sblock.e2fs.e2fs_log_bsize;
    330 	sblock.e2fs_qbmask = sblock.e2fs_bsize - 1;
    331 	sblock.e2fs_bmask = ~sblock.e2fs_qbmask;
    332 	sblock.e2fs_ngdb = howmany(sblock.e2fs_ncg,
    333 	    sblock.e2fs_bsize / sizeof(struct ext2_gd));
    334 	sblock.e2fs_ipb = sblock.e2fs_bsize / EXT2_DINODE_SIZE(&sblock);
    335 	sblock.e2fs_itpg = howmany(sblock.e2fs.e2fs_ipg, sblock.e2fs_ipb);
    336 
    337 	/*
    338 	 * Compute block size that the filesystem is based on,
    339 	 * according to fsbtodb, and adjust superblock block number
    340 	 * so we can tell if this is an alternate later.
    341 	 */
    342 	super *= dev_bsize;
    343 	dev_bsize = sblock.e2fs_bsize / fsbtodb(&sblock, 1);
    344 	sblk.b_bno = super / dev_bsize;
    345 
    346 	if (sblock.e2fs_ncg == 1) {
    347 		/* no alternate superblock; assume it's okay */
    348 		havesb = 1;
    349 		return 1;
    350 	}
    351 	getblk(&asblk, 1 * sblock.e2fs.e2fs_bpg + sblock.e2fs.e2fs_first_dblock,
    352 		(long)SBSIZE);
    353 	if (asblk.b_errs)
    354 		return 0;
    355 	if (bflag) {
    356 		havesb = 1;
    357 		return 1;
    358 	}
    359 
    360 	/*
    361 	 * Set all possible fields that could differ, then do check
    362 	 * of whole super block against an alternate super block.
    363 	 * When an alternate super-block is specified this check is skipped.
    364 	 */
    365 	asblk.b_un.b_fs->e2fs_rbcount = sblk.b_un.b_fs->e2fs_rbcount;
    366 	asblk.b_un.b_fs->e2fs_fbcount = sblk.b_un.b_fs->e2fs_fbcount;
    367 	asblk.b_un.b_fs->e2fs_ficount = sblk.b_un.b_fs->e2fs_ficount;
    368 	asblk.b_un.b_fs->e2fs_mtime = sblk.b_un.b_fs->e2fs_mtime;
    369 	asblk.b_un.b_fs->e2fs_wtime = sblk.b_un.b_fs->e2fs_wtime;
    370 	asblk.b_un.b_fs->e2fs_mnt_count = sblk.b_un.b_fs->e2fs_mnt_count;
    371 	asblk.b_un.b_fs->e2fs_max_mnt_count =
    372 	    sblk.b_un.b_fs->e2fs_max_mnt_count;
    373 	asblk.b_un.b_fs->e2fs_state = sblk.b_un.b_fs->e2fs_state;
    374 	asblk.b_un.b_fs->e2fs_beh = sblk.b_un.b_fs->e2fs_beh;
    375 	asblk.b_un.b_fs->e2fs_lastfsck = sblk.b_un.b_fs->e2fs_lastfsck;
    376 	asblk.b_un.b_fs->e2fs_fsckintv = sblk.b_un.b_fs->e2fs_fsckintv;
    377 	asblk.b_un.b_fs->e2fs_ruid = sblk.b_un.b_fs->e2fs_ruid;
    378 	asblk.b_un.b_fs->e2fs_rgid = sblk.b_un.b_fs->e2fs_rgid;
    379 	asblk.b_un.b_fs->e2fs_block_group_nr =
    380 	    sblk.b_un.b_fs->e2fs_block_group_nr;
    381 	asblk.b_un.b_fs->e2fs_features_rocompat &= ~EXT2F_ROCOMPAT_LARGEFILE;
    382 	asblk.b_un.b_fs->e2fs_features_rocompat |=
    383 	    sblk.b_un.b_fs->e2fs_features_rocompat & EXT2F_ROCOMPAT_LARGEFILE;
    384 	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
    385 	    ((sblock.e2fs.e2fs_features_incompat & ~EXT2F_INCOMPAT_SUPP) ||
    386 	    (sblock.e2fs.e2fs_features_rocompat & ~EXT2F_ROCOMPAT_SUPP))) {
    387 		if (debug) {
    388 			printf("compat 0x%08x, incompat 0x%08x, compat_ro "
    389 			    "0x%08x\n",
    390 			    sblock.e2fs.e2fs_features_compat,
    391 			    sblock.e2fs.e2fs_features_incompat,
    392 			    sblock.e2fs.e2fs_features_rocompat);
    393 		}
    394 		badsb(listerr, "INCOMPATIBLE FEATURE BITS IN SUPER BLOCK");
    395 		return 0;
    396 	}
    397 	if (memcmp(sblk.b_un.b_fs, asblk.b_un.b_fs, SBSIZE)) {
    398 		if (debug) {
    399 			u_int32_t *nlp, *olp, *endlp;
    400 
    401 			printf("superblock mismatches\n");
    402 			nlp = (u_int32_t *)asblk.b_un.b_fs;
    403 			olp = (u_int32_t *)sblk.b_un.b_fs;
    404 			endlp = olp + (SBSIZE / sizeof(*olp));
    405 			for ( ; olp < endlp; olp++, nlp++) {
    406 				if (*olp == *nlp)
    407 					continue;
    408 				printf("offset %ld, original %ld, "
    409 				    "alternate %ld\n",
    410 				    (long)(olp - (u_int32_t *)sblk.b_un.b_fs),
    411 				    (long)fs2h32(*olp),
    412 				    (long)fs2h32(*nlp));
    413 			}
    414 		}
    415 		badsb(listerr,
    416 		    "VALUES IN SUPER BLOCK DISAGREE WITH "
    417 		    "THOSE IN FIRST ALTERNATE");
    418 		return 0;
    419 	}
    420 	havesb = 1;
    421 	return 1;
    422 }
    423 
    424 void
    425 copyback_sb(struct bufarea *bp)
    426 {
    427 	/* Copy the in-memory superblock back to buffer */
    428 	bp->b_un.b_fs->e2fs_icount = h2fs32(sblock.e2fs.e2fs_icount);
    429 	bp->b_un.b_fs->e2fs_bcount = h2fs32(sblock.e2fs.e2fs_bcount);
    430 	bp->b_un.b_fs->e2fs_rbcount = h2fs32(sblock.e2fs.e2fs_rbcount);
    431 	bp->b_un.b_fs->e2fs_fbcount = h2fs32(sblock.e2fs.e2fs_fbcount);
    432 	bp->b_un.b_fs->e2fs_ficount = h2fs32(sblock.e2fs.e2fs_ficount);
    433 	bp->b_un.b_fs->e2fs_first_dblock =
    434 	    h2fs32(sblock.e2fs.e2fs_first_dblock);
    435 	bp->b_un.b_fs->e2fs_log_bsize = h2fs32(sblock.e2fs.e2fs_log_bsize);
    436 	bp->b_un.b_fs->e2fs_fsize = h2fs32(sblock.e2fs.e2fs_fsize);
    437 	bp->b_un.b_fs->e2fs_bpg = h2fs32(sblock.e2fs.e2fs_bpg);
    438 	bp->b_un.b_fs->e2fs_fpg = h2fs32(sblock.e2fs.e2fs_fpg);
    439 	bp->b_un.b_fs->e2fs_ipg = h2fs32(sblock.e2fs.e2fs_ipg);
    440 	bp->b_un.b_fs->e2fs_mtime = h2fs32(sblock.e2fs.e2fs_mtime);
    441 	bp->b_un.b_fs->e2fs_wtime = h2fs32(sblock.e2fs.e2fs_wtime);
    442 	bp->b_un.b_fs->e2fs_lastfsck = h2fs32(sblock.e2fs.e2fs_lastfsck);
    443 	bp->b_un.b_fs->e2fs_fsckintv = h2fs32(sblock.e2fs.e2fs_fsckintv);
    444 	bp->b_un.b_fs->e2fs_creator = h2fs32(sblock.e2fs.e2fs_creator);
    445 	bp->b_un.b_fs->e2fs_rev = h2fs32(sblock.e2fs.e2fs_rev);
    446 	bp->b_un.b_fs->e2fs_mnt_count = h2fs16(sblock.e2fs.e2fs_mnt_count);
    447 	bp->b_un.b_fs->e2fs_max_mnt_count =
    448 	    h2fs16(sblock.e2fs.e2fs_max_mnt_count);
    449 	bp->b_un.b_fs->e2fs_magic = h2fs16(sblock.e2fs.e2fs_magic);
    450 	bp->b_un.b_fs->e2fs_state = h2fs16(sblock.e2fs.e2fs_state);
    451 	bp->b_un.b_fs->e2fs_beh = h2fs16(sblock.e2fs.e2fs_beh);
    452 	bp->b_un.b_fs->e2fs_ruid = h2fs16(sblock.e2fs.e2fs_ruid);
    453 	bp->b_un.b_fs->e2fs_rgid = h2fs16(sblock.e2fs.e2fs_rgid);
    454 }
    455 
    456 void
    457 badsb(int listerr, const char *s)
    458 {
    459 
    460 	if (!listerr)
    461 		return;
    462 	if (preen)
    463 		printf("%s: ", cdevname());
    464 	pfatal("BAD SUPER BLOCK: %s\n", s);
    465 }
    466 
    467 /*
    468  * Calculate a prototype superblock based on information in the disk label.
    469  * When done the cgsblock macro can be calculated and the fs_ncg field
    470  * can be used. Do NOT attempt to use other macros without verifying that
    471  * their needed information is available!
    472  */
    473 
    474 int
    475 calcsb(const char *dev, int devfd, struct m_ext2fs *fs)
    476 {
    477 	struct disklabel *lp;
    478 	struct partition *pp;
    479 	char *cp;
    480 
    481 	cp = strchr(dev, '\0');
    482 	if (cp-- == dev ||
    483 	    ((*cp < 'a' || *cp > 'h') && !isdigit((unsigned char)*cp))) {
    484 		pfatal("%s: CANNOT FIGURE OUT FILE SYSTEM PARTITION\n", dev);
    485 		return 0;
    486 	}
    487 	lp = getdisklabel(dev, devfd);
    488 	if (isdigit((unsigned char)*cp))
    489 		pp = &lp->d_partitions[0];
    490 	else
    491 		pp = &lp->d_partitions[*cp - 'a'];
    492 	if (pp->p_fstype != FS_EX2FS) {
    493 		pfatal("%s: NOT LABELED AS A EXT2 FILE SYSTEM (%s)\n",
    494 		    dev, pp->p_fstype < FSMAXTYPES ?
    495 		    fstypenames[pp->p_fstype] : "unknown");
    496 		return 0;
    497 	}
    498 	memset(fs, 0, sizeof(struct m_ext2fs));
    499 	fs->e2fs_bsize = pp->p_fsize;
    500 	fs->e2fs.e2fs_log_bsize = pp->p_fsize / 1024;
    501 	fs->e2fs.e2fs_bcount = (pp->p_size * DEV_BSIZE) / fs->e2fs_bsize;
    502 	fs->e2fs.e2fs_first_dblock = (fs->e2fs.e2fs_log_bsize == 0) ? 1 : 0;
    503 	fs->e2fs.e2fs_bpg = fs->e2fs_bsize * NBBY;
    504 	fs->e2fs_bshift = LOG_MINBSIZE + fs->e2fs.e2fs_log_bsize;
    505 	fs->e2fs_qbmask = fs->e2fs_bsize - 1;
    506 	fs->e2fs_bmask = ~fs->e2fs_qbmask;
    507 	fs->e2fs_ncg =
    508 	    howmany(fs->e2fs.e2fs_bcount - fs->e2fs.e2fs_first_dblock,
    509 	    fs->e2fs.e2fs_bpg);
    510 	fs->e2fs_fsbtodb = fs->e2fs.e2fs_log_bsize + 1;
    511 	fs->e2fs_ngdb = howmany(fs->e2fs_ncg,
    512 	    fs->e2fs_bsize / sizeof(struct ext2_gd));
    513 
    514 	return 1;
    515 }
    516 
    517 static struct disklabel *
    518 getdisklabel(const char *s, int fd)
    519 {
    520 	static struct disklabel lab;
    521 
    522 	if (ioctl(fd, DIOCGDINFO, (char *)&lab) < 0) {
    523 		if (s == NULL)
    524 			return NULL;
    525 		pwarn("ioctl (GCINFO): %s\n", strerror(errno));
    526 		errexit("%s: can't read disk label", s);
    527 	}
    528 	return &lab;
    529 }
    530 
    531 daddr_t
    532 cgoverhead(int c)
    533 {
    534 	int overh;
    535 	overh =
    536 	    1 /* block bitmap */ +
    537 	    1 /* inode bitmap */ +
    538 	    sblock.e2fs_itpg;
    539 	if (sblock.e2fs.e2fs_rev > E2FS_REV0 &&
    540 	    sblock.e2fs.e2fs_features_rocompat & EXT2F_ROCOMPAT_SPARSESUPER) {
    541 		if (cg_has_sb(c) == 0)
    542 			return overh;
    543 	}
    544 	overh += 1 /* superblock */ + sblock.e2fs_ngdb;
    545 	return overh;
    546 }
    547