Home | History | Annotate | Line # | Download | only in tunefs
tunefs.c revision 1.50
      1 /*	$NetBSD: tunefs.c,v 1.50 2019/04/12 01:14:37 pgoyette Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1983, 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 #include <sys/cdefs.h>
     33 #ifndef lint
     34 __COPYRIGHT("@(#) Copyright (c) 1983, 1993\
     35  The Regents of the University of California.  All rights reserved.");
     36 #endif /* not lint */
     37 
     38 #ifndef lint
     39 #if 0
     40 static char sccsid[] = "@(#)tunefs.c	8.3 (Berkeley) 5/3/95";
     41 #else
     42 __RCSID("$NetBSD: tunefs.c,v 1.50 2019/04/12 01:14:37 pgoyette Exp $");
     43 #endif
     44 #endif /* not lint */
     45 
     46 /*
     47  * tunefs: change layout parameters to an existing file system.
     48  */
     49 #include <sys/param.h>
     50 
     51 #include <ufs/ffs/fs.h>
     52 #include <ufs/ffs/ffs_extern.h>
     53 #include <ufs/ufs/ufs_wapbl.h>
     54 #include <ufs/ufs/quota2.h>
     55 
     56 #include <machine/bswap.h>
     57 
     58 #include <err.h>
     59 #include <errno.h>
     60 #include <fcntl.h>
     61 #include <fstab.h>
     62 #include <paths.h>
     63 #include <stdio.h>
     64 #include <stdlib.h>
     65 #include <string.h>
     66 #include <unistd.h>
     67 #include <util.h>
     68 
     69 /* the optimization warning string template */
     70 #define	OPTWARN	"should optimize for %s with minfree %s %d%%"
     71 
     72 union {
     73 	struct	fs sb;
     74 	char data[MAXBSIZE];
     75 } sbun, buf;
     76 #define	sblock sbun.sb
     77 
     78 int	fi;
     79 long	dev_bsize = 512;
     80 int	needswap = 0;
     81 int	is_ufs2 = 0;
     82 off_t	sblockloc;
     83 int	userquota = 0;
     84 int	groupquota = 0;
     85 #define Q2_EN  (1)
     86 #define Q2_IGN (0)
     87 #define Q2_DIS (-1)
     88 
     89 static off_t sblock_try[] = SBLOCKSEARCH;
     90 
     91 static	void	bwrite(daddr_t, char *, int, const char *);
     92 static	void	bread(daddr_t, char *, int, const char *);
     93 static	void	change_log_info(long long);
     94 static	void	getsb(struct fs *, const char *);
     95 static	int	openpartition(const char *, int, char *, size_t);
     96 static	void	show_log_info(void);
     97 __dead static	void	usage(void);
     98 
     99 int
    100 main(int argc, char *argv[])
    101 {
    102 	int		i, ch, Aflag, Fflag, Nflag, openflags;
    103 	const char	*special, *chg[2];
    104 	char		device[MAXPATHLEN];
    105 	int		maxbpg, minfree, optim, secsize;
    106 	int		avgfilesize, avgfpdir;
    107 	long long	logfilesize;
    108 	int		secshift, fsbtodb;
    109 
    110 	Aflag = Fflag = Nflag = 0;
    111 	maxbpg = minfree = optim = secsize = -1;
    112 	avgfilesize = avgfpdir = -1;
    113 	logfilesize = -1;
    114 	secshift = 0;
    115 	chg[FS_OPTSPACE] = "space";
    116 	chg[FS_OPTTIME] = "time";
    117 
    118 	while ((ch = getopt(argc, argv, "AFNe:g:h:l:m:o:q:S:")) != -1) {
    119 		switch (ch) {
    120 
    121 		case 'A':
    122 			Aflag++;
    123 			break;
    124 
    125 		case 'F':
    126 			Fflag++;
    127 			break;
    128 
    129 		case 'N':
    130 			Nflag++;
    131 			break;
    132 
    133 		case 'e':
    134 			maxbpg = strsuftoll(
    135 			    "maximum blocks per file in a cylinder group",
    136 			    optarg, 1, INT_MAX);
    137 			break;
    138 
    139 		case 'g':
    140 			avgfilesize = strsuftoll("average file size", optarg,
    141 			    1, INT_MAX);
    142 			break;
    143 
    144 		case 'h':
    145 			avgfpdir = strsuftoll(
    146 			    "expected number of files per directory",
    147 			    optarg, 1, INT_MAX);
    148 			break;
    149 
    150 		case 'l':
    151 			logfilesize = strsuftoll("journal log file size",
    152 			    optarg, 0, INT_MAX);
    153 			break;
    154 
    155 		case 'm':
    156 			minfree = strsuftoll("minimum percentage of free space",
    157 			    optarg, 0, 99);
    158 			break;
    159 
    160 		case 'o':
    161 			if (strcmp(optarg, chg[FS_OPTSPACE]) == 0)
    162 				optim = FS_OPTSPACE;
    163 			else if (strcmp(optarg, chg[FS_OPTTIME]) == 0)
    164 				optim = FS_OPTTIME;
    165 			else
    166 				errx(10,
    167 				    "bad %s (options are `space' or `time')",
    168 				    "optimization preference");
    169 			break;
    170 		case 'q':
    171 			if      (strcmp(optarg, "user") == 0)
    172 				userquota = Q2_EN;
    173 			else if (strcmp(optarg, "group") == 0)
    174 				groupquota = Q2_EN;
    175 			else if (strcmp(optarg, "nouser") == 0)
    176 				userquota = Q2_DIS;
    177 			else if (strcmp(optarg, "nogroup") == 0)
    178 				groupquota = Q2_DIS;
    179 			else
    180 			    errx(11, "invalid quota type %s", optarg);
    181 			break;
    182 		case 'S':
    183 			secsize = strsuftoll("physical sector size",
    184 			    optarg, 0, INT_MAX);
    185 			secshift = ffs(secsize) - 1;
    186 			if (secsize != 0 && 1 << secshift != secsize)
    187 				errx(12, "sector size %d is not a power of two", secsize);
    188 			break;
    189 		default:
    190 			usage();
    191 		}
    192 	}
    193 	argc -= optind;
    194 	argv += optind;
    195 	if (argc != 1)
    196 		usage();
    197 
    198 	special = argv[0];
    199 	openflags = Nflag ? O_RDONLY : O_RDWR;
    200 	if (Fflag)
    201 		fi = open(special, openflags);
    202 	else {
    203 		fi = openpartition(special, openflags, device, sizeof(device));
    204 		special = device;
    205 	}
    206 	if (fi == -1)
    207 		err(1, "%s", special);
    208 	getsb(&sblock, special);
    209 
    210 #define CHANGEVAL(old, new, type, suffix) do				\
    211 	if ((new) != -1) {						\
    212 		if ((new) == (old))					\
    213 			warnx("%s remains unchanged at %d%s",		\
    214 			    (type), (old), (suffix));			\
    215 		else {							\
    216 			warnx("%s changes from %d%s to %d%s",		\
    217 			    (type), (old), (suffix), (new), (suffix));	\
    218 			(old) = (new);					\
    219 		}							\
    220 	} while (/* CONSTCOND */0)
    221 
    222 	warnx("tuning %s", special);
    223 	CHANGEVAL(sblock.fs_maxbpg, maxbpg,
    224 	    "maximum blocks per file in a cylinder group", "");
    225 	CHANGEVAL(sblock.fs_minfree, minfree,
    226 	    "minimum percentage of free space", "%");
    227 	if (minfree != -1) {
    228 		if (minfree >= MINFREE &&
    229 		    sblock.fs_optim == FS_OPTSPACE)
    230 			warnx(OPTWARN, "time", ">=", MINFREE);
    231 		if (minfree < MINFREE &&
    232 		    sblock.fs_optim == FS_OPTTIME)
    233 			warnx(OPTWARN, "space", "<", MINFREE);
    234 	}
    235 	if (optim != -1) {
    236 		if (sblock.fs_optim == optim) {
    237 			warnx("%s remains unchanged as %s",
    238 			    "optimization preference",
    239 			    chg[optim]);
    240 		} else {
    241 			warnx("%s changes from %s to %s",
    242 			    "optimization preference",
    243 			    chg[sblock.fs_optim], chg[optim]);
    244 			sblock.fs_optim = optim;
    245 			if (sblock.fs_minfree >= MINFREE &&
    246 			    optim == FS_OPTSPACE)
    247 				warnx(OPTWARN, "time", ">=", MINFREE);
    248 			if (sblock.fs_minfree < MINFREE &&
    249 			    optim == FS_OPTTIME)
    250 				warnx(OPTWARN, "space", "<", MINFREE);
    251 		}
    252 	}
    253 	if (secsize != -1) {
    254 		if (secsize == 0) {
    255 			secsize = sblock.fs_fsize / FFS_FSBTODB(&sblock, 1);
    256 			secshift = ffs(secsize) - 1;
    257 		}
    258 
    259 		if (secshift < DEV_BSHIFT)
    260 			warnx("sector size must be at least %d", DEV_BSIZE);
    261 		else if (secshift > sblock.fs_fshift)
    262 			warnx("sector size %d cannot be larger than fragment size %d",
    263 				secsize, sblock.fs_fsize);
    264 		else {
    265 			fsbtodb = sblock.fs_fshift - secshift;
    266 			if (fsbtodb == sblock.fs_fsbtodb) {
    267 				warnx("sector size remains unchanged as %d",
    268 					sblock.fs_fsize / FFS_FSBTODB(&sblock, 1));
    269 			} else {
    270 				warnx("sector size changed from %d to %d",
    271 					sblock.fs_fsize / FFS_FSBTODB(&sblock, 1),
    272 					secsize);
    273 				sblock.fs_fsbtodb = fsbtodb;
    274 			}
    275 		}
    276 	}
    277 	CHANGEVAL(sblock.fs_avgfilesize, avgfilesize,
    278 	    "average file size", "");
    279 	CHANGEVAL(sblock.fs_avgfpdir, avgfpdir,
    280 	    "expected number of files per directory", "");
    281 
    282 	if (logfilesize >= 0)
    283 		change_log_info(logfilesize);
    284 	if (userquota == Q2_EN || groupquota == Q2_EN)
    285 		sblock.fs_flags |= FS_DOQUOTA2;
    286 	if (sblock.fs_flags & FS_DOQUOTA2) {
    287 		sblock.fs_quota_magic = Q2_HEAD_MAGIC;
    288 		switch(userquota) {
    289 		case Q2_EN:
    290 			if ((sblock.fs_quota_flags & FS_Q2_DO_TYPE(USRQUOTA))
    291 			    == 0) {
    292 				printf("enabling user quotas\n");
    293 				sblock.fs_quota_flags |=
    294 				    FS_Q2_DO_TYPE(USRQUOTA);
    295 				sblock.fs_quotafile[USRQUOTA] = 0;
    296 			}
    297 			break;
    298 		case Q2_DIS:
    299 			if ((sblock.fs_quota_flags & FS_Q2_DO_TYPE(USRQUOTA))
    300 			    != 0) {
    301 				printf("disabling user quotas\n");
    302 				sblock.fs_quota_flags &=
    303 				    ~FS_Q2_DO_TYPE(USRQUOTA);
    304 			}
    305 		}
    306 		switch(groupquota) {
    307 		case Q2_EN:
    308 			if ((sblock.fs_quota_flags & FS_Q2_DO_TYPE(GRPQUOTA))
    309 			    == 0) {
    310 				printf("enabling group quotas\n");
    311 				sblock.fs_quota_flags |=
    312 				    FS_Q2_DO_TYPE(GRPQUOTA);
    313 				sblock.fs_quotafile[GRPQUOTA] = 0;
    314 			}
    315 			break;
    316 		case Q2_DIS:
    317 			if ((sblock.fs_quota_flags & FS_Q2_DO_TYPE(GRPQUOTA))
    318 			    != 0) {
    319 				printf("disabling group quotas\n");
    320 				sblock.fs_quota_flags &=
    321 				    ~FS_Q2_DO_TYPE(GRPQUOTA);
    322 			}
    323 		}
    324 	}
    325 	/*
    326 	 * if we disabled all quotas, FS_DOQUOTA2 and associated inode(s) will
    327 	 * be cleared by kernel or fsck.
    328 	 */
    329 
    330 	if (Nflag) {
    331 		printf("tunefs: current settings of %s\n", special);
    332 		printf("\tmaximum contiguous block count %d\n",
    333 		    sblock.fs_maxcontig);
    334 		printf("\tmaximum blocks per file in a cylinder group %d\n",
    335 		    sblock.fs_maxbpg);
    336 		printf("\tminimum percentage of free space %d%%\n",
    337 		    sblock.fs_minfree);
    338 		printf("\toptimization preference: %s\n", chg[sblock.fs_optim]);
    339 		printf("\taverage file size: %d\n", sblock.fs_avgfilesize);
    340 		printf("\texpected number of files per directory: %d\n",
    341 		    sblock.fs_avgfpdir);
    342 		show_log_info();
    343 		printf("\tquotas");
    344 		if (sblock.fs_flags & FS_DOQUOTA2) {
    345 			if (sblock.fs_quota_flags & FS_Q2_DO_TYPE(USRQUOTA)) {
    346 				printf(" user");
    347 				if (sblock.fs_quota_flags &
    348 				    FS_Q2_DO_TYPE(GRPQUOTA))
    349 					printf(",");
    350 			}
    351 			if (sblock.fs_quota_flags & FS_Q2_DO_TYPE(GRPQUOTA))
    352 				printf(" group");
    353 			printf(" enabled\n");
    354 		} else {
    355 			printf(" disabled\n");
    356 		}
    357 		printf("tunefs: no changes made\n");
    358 		exit(0);
    359 	}
    360 
    361 	memcpy(&buf, (char *)&sblock, SBLOCKSIZE);
    362 	if (needswap)
    363 		ffs_sb_swap((struct fs*)&buf, (struct fs*)&buf);
    364 
    365 	/* write superblock to original coordinates (use old dev_bsize!) */
    366 	bwrite(sblockloc, buf.data, SBLOCKSIZE, special);
    367 
    368 	/* correct dev_bsize from possibly changed superblock data */
    369 	dev_bsize = sblock.fs_fsize / FFS_FSBTODB(&sblock, 1);
    370 
    371 	if (Aflag)
    372 		for (i = 0; i < sblock.fs_ncg; i++)
    373 			bwrite(FFS_FSBTODB(&sblock, cgsblock(&sblock, i)),
    374 			    buf.data, SBLOCKSIZE, special);
    375 	close(fi);
    376 	exit(0);
    377 }
    378 
    379 static void
    380 show_log_info(void)
    381 {
    382 	const char *loc;
    383 	uint64_t size, blksize, logsize;
    384 	int print;
    385 
    386 	switch (sblock.fs_journal_location) {
    387 	case UFS_WAPBL_JOURNALLOC_NONE:
    388 		print = blksize = 0;
    389 		/* nothing */
    390 		break;
    391 	case UFS_WAPBL_JOURNALLOC_END_PARTITION:
    392 		loc = "end of partition";
    393 		size = sblock.fs_journallocs[UFS_WAPBL_EPART_COUNT];
    394 		blksize = sblock.fs_journallocs[UFS_WAPBL_EPART_BLKSZ];
    395 		print = 1;
    396 		break;
    397 	case UFS_WAPBL_JOURNALLOC_IN_FILESYSTEM:
    398 		loc = "in filesystem";
    399 		size = sblock.fs_journallocs[UFS_WAPBL_INFS_COUNT];
    400 		blksize = sblock.fs_journallocs[UFS_WAPBL_INFS_BLKSZ];
    401 		print = 1;
    402 		break;
    403 	default:
    404 		loc = "unknown";
    405 		size = blksize = 0;
    406 		print = 1;
    407 		break;
    408 	}
    409 
    410 	if (print) {
    411 		logsize = size * blksize;
    412 
    413 		printf("\tjournal log file location: %s\n", loc);
    414 		printf("\tjournal log file size: ");
    415 		if (logsize == 0)
    416 			printf("0\n");
    417 		else {
    418 			char sizebuf[8];
    419 			humanize_number(sizebuf, 6, size * blksize, "B",
    420 			    HN_AUTOSCALE, HN_B | HN_NOSPACE | HN_DECIMAL);
    421 			printf("%s (%" PRId64 " bytes)", sizebuf, logsize);
    422 		}
    423 		printf("\n");
    424 		printf("\tjournal log flags:");
    425 		if (sblock.fs_journal_flags & UFS_WAPBL_FLAGS_CREATE_LOG)
    426 			printf(" create-log");
    427 		if (sblock.fs_journal_flags & UFS_WAPBL_FLAGS_CLEAR_LOG)
    428 			printf(" clear-log");
    429 		printf("\n");
    430 	}
    431 }
    432 
    433 static void
    434 change_log_info(long long logfilesize)
    435 {
    436 	/*
    437 	 * NOTES:
    438 	 *  - only operate on in-filesystem log sizes
    439 	 *  - can't change size of existing log
    440 	 *  - if current is same, no action
    441 	 *  - if current is zero and new is non-zero, set flag to create log
    442 	 *    on next mount
    443 	 *  - if current is non-zero and new is zero, set flag to clear log
    444 	 *    on next mount
    445 	 */
    446 	int in_fs_log;
    447 	uint64_t old_size;
    448 
    449 	old_size = 0;
    450 	switch (sblock.fs_journal_location) {
    451 	case UFS_WAPBL_JOURNALLOC_END_PARTITION:
    452 		in_fs_log = 0;
    453 		old_size = sblock.fs_journallocs[UFS_WAPBL_EPART_COUNT] *
    454 		    sblock.fs_journallocs[UFS_WAPBL_EPART_BLKSZ];
    455 		break;
    456 
    457 	case UFS_WAPBL_JOURNALLOC_IN_FILESYSTEM:
    458 		in_fs_log = 1;
    459 		old_size = sblock.fs_journallocs[UFS_WAPBL_INFS_COUNT] *
    460 		    sblock.fs_journallocs[UFS_WAPBL_INFS_BLKSZ];
    461 		break;
    462 
    463 	case UFS_WAPBL_JOURNALLOC_NONE:
    464 	default:
    465 		in_fs_log = 0;
    466 		old_size = 0;
    467 		break;
    468 	}
    469 
    470 	if (logfilesize == 0) {
    471 		/*
    472 		 * Don't clear out the locators - the kernel might need
    473 		 * these to find the log!  Just set the "clear the log"
    474 		 * flag and let the kernel do the rest.
    475 		 */
    476 		sblock.fs_journal_flags |= UFS_WAPBL_FLAGS_CLEAR_LOG;
    477 		sblock.fs_journal_flags &= ~UFS_WAPBL_FLAGS_CREATE_LOG;
    478 		warnx("log file size cleared from %" PRIu64 "", old_size);
    479 		return;
    480 	}
    481 
    482 	if (!in_fs_log && logfilesize > 0 && old_size > 0)
    483 		errx(1, "Can't change size of non-in-filesystem log");
    484 
    485 	if (old_size == (uint64_t)logfilesize && logfilesize > 0) {
    486 		/* no action */
    487 		warnx("log file size remains unchanged at %lld", logfilesize);
    488 		return;
    489 	}
    490 
    491 	if (old_size == 0) {
    492 		/* create new log of desired size next mount */
    493 		sblock.fs_journal_location = UFS_WAPBL_JOURNALLOC_IN_FILESYSTEM;
    494 		sblock.fs_journallocs[UFS_WAPBL_INFS_ADDR] = 0;
    495 		sblock.fs_journallocs[UFS_WAPBL_INFS_COUNT] = logfilesize;
    496 		sblock.fs_journallocs[UFS_WAPBL_INFS_BLKSZ] = 0;
    497 		sblock.fs_journallocs[UFS_WAPBL_INFS_INO] = 0;
    498 		sblock.fs_journal_flags |= UFS_WAPBL_FLAGS_CREATE_LOG;
    499 		sblock.fs_journal_flags &= ~UFS_WAPBL_FLAGS_CLEAR_LOG;
    500 		warnx("log file size set to %lld", logfilesize);
    501 	} else {
    502 		errx(1,
    503 		    "Can't change existing log size from %" PRIu64 " to %lld",
    504 		     old_size, logfilesize);
    505 	}
    506 }
    507 
    508 static void
    509 usage(void)
    510 {
    511 
    512 	fprintf(stderr, "usage: tunefs [-AFN] tuneup-options special-device\n");
    513 	fprintf(stderr, "where tuneup-options are:\n");
    514 	fprintf(stderr, "\t-e maximum blocks per file in a cylinder group\n");
    515 	fprintf(stderr, "\t-g average file size\n");
    516 	fprintf(stderr, "\t-h expected number of files per directory\n");
    517 	fprintf(stderr, "\t-l journal log file size (`0' to clear journal)\n");
    518 	fprintf(stderr, "\t-m minimum percentage of free space\n");
    519 	fprintf(stderr, "\t-o optimization preference (`space' or `time')\n");
    520 	fprintf(stderr, "\t-q quota type (`[no]user' or `[no]group')\n");
    521 	fprintf(stderr, "\t-S sector size\n");
    522 	exit(2);
    523 }
    524 
    525 static void
    526 getsb(struct fs *fs, const char *file)
    527 {
    528 	int i;
    529 
    530 	for (i = 0; ; i++) {
    531 		if (sblock_try[i] == -1)
    532 			errx(5, "cannot find filesystem superblock");
    533 		bread(sblock_try[i] / dev_bsize, (char *)fs, SBLOCKSIZE, file);
    534 		switch(fs->fs_magic) {
    535 		case FS_UFS2_MAGIC:
    536 			is_ufs2 = 1;
    537 			/*FALLTHROUGH*/
    538 		case FS_UFS1_MAGIC:
    539 			break;
    540 		case FS_UFS2_MAGIC_SWAPPED:
    541 			is_ufs2 = 1;
    542 			/*FALLTHROUGH*/
    543 		case FS_UFS1_MAGIC_SWAPPED:
    544 			warnx("%s: swapping byte order", file);
    545 			needswap = 1;
    546 			ffs_sb_swap(fs, fs);
    547 			break;
    548 		default:
    549 			continue;
    550 		}
    551 		if (!is_ufs2 && sblock_try[i] == SBLOCK_UFS2)
    552 			continue;
    553 		if ((is_ufs2 || fs->fs_old_flags & FS_FLAGS_UPDATED)
    554 		    && fs->fs_sblockloc != sblock_try[i])
    555 			continue;
    556 		break;
    557 	}
    558 
    559 	dev_bsize = fs->fs_fsize / FFS_FSBTODB(fs, 1);
    560 	sblockloc = sblock_try[i] / dev_bsize;
    561 }
    562 
    563 static void
    564 bwrite(daddr_t blk, char *buffer, int size, const char *file)
    565 {
    566 	off_t	offset;
    567 
    568 	offset = (off_t)blk * dev_bsize;
    569 	if (lseek(fi, offset, SEEK_SET) == -1)
    570 		err(6, "%s: seeking to %lld", file, (long long)offset);
    571 	if (write(fi, buffer, size) != size)
    572 		err(7, "%s: writing %d bytes", file, size);
    573 }
    574 
    575 static void
    576 bread(daddr_t blk, char *buffer, int cnt, const char *file)
    577 {
    578 	off_t	offset;
    579 	int	i;
    580 
    581 	offset = (off_t)blk * dev_bsize;
    582 	if (lseek(fi, offset, SEEK_SET) == -1)
    583 		err(4, "%s: seeking to %lld", file, (long long)offset);
    584 	if ((i = read(fi, buffer, cnt)) != cnt)
    585 		errx(5, "%s: short read", file);
    586 }
    587 
    588 static int
    589 openpartition(const char *name, int flags, char *device, size_t devicelen)
    590 {
    591 	char		specname[MAXPATHLEN];
    592 	char		rawname[MAXPATHLEN];
    593 	const char	*special, *raw;
    594 	struct fstab	*fs;
    595 	int		fd, oerrno;
    596 
    597 	fs = getfsfile(name);
    598 	special = fs ? fs->fs_spec : name;
    599 
    600 	raw = getfsspecname(specname, sizeof(specname), special);
    601 	if (raw == NULL)
    602 		err(1, "%s: %s", name, specname);
    603 	special = getdiskrawname(rawname, sizeof(rawname), raw);
    604 	if (special == NULL)
    605 		special = raw;
    606 
    607 	fd = opendisk(special, flags, device, devicelen, 0);
    608 	if (fd == -1 && errno == ENOENT) {
    609 		oerrno = errno;
    610 		strlcpy(device, special, devicelen);
    611 		errno = oerrno;
    612 	}
    613 	return (fd);
    614 }
    615