Home | History | Annotate | Line # | Download | only in newfs
mkfs.c revision 1.99
      1 /*	$NetBSD: mkfs.c,v 1.99 2006/01/16 21:34:41 dsl Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1980, 1989, 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) 2002 Networks Associates Technology, Inc.
     34  * All rights reserved.
     35  *
     36  * This software was developed for the FreeBSD Project by Marshall
     37  * Kirk McKusick and Network Associates Laboratories, the Security
     38  * Research Division of Network Associates, Inc. under DARPA/SPAWAR
     39  * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS
     40  * research program
     41  *
     42  * Redistribution and use in source and binary forms, with or without
     43  * modification, are permitted provided that the following conditions
     44  * are met:
     45  * 1. Redistributions of source code must retain the above copyright
     46  *    notice, this list of conditions and the following disclaimer.
     47  * 2. Redistributions in binary form must reproduce the above copyright
     48  *    notice, this list of conditions and the following disclaimer in the
     49  *    documentation and/or other materials provided with the distribution.
     50  * 3. All advertising materials mentioning features or use of this software
     51  *    must display the following acknowledgement:
     52  *	This product includes software developed by the University of
     53  *	California, Berkeley and its contributors.
     54  * 4. Neither the name of the University nor the names of its contributors
     55  *    may be used to endorse or promote products derived from this software
     56  *    without specific prior written permission.
     57  *
     58  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     59  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     60  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     61  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     62  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     63  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     64  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     65  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     66  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     67  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     68  * SUCH DAMAGE.
     69  */
     70 
     71 #include <sys/cdefs.h>
     72 #ifndef lint
     73 #if 0
     74 static char sccsid[] = "@(#)mkfs.c	8.11 (Berkeley) 5/3/95";
     75 #else
     76 __RCSID("$NetBSD: mkfs.c,v 1.99 2006/01/16 21:34:41 dsl Exp $");
     77 #endif
     78 #endif /* not lint */
     79 
     80 #include <sys/param.h>
     81 #include <sys/mman.h>
     82 #include <sys/time.h>
     83 #include <sys/resource.h>
     84 #include <ufs/ufs/dinode.h>
     85 #include <ufs/ufs/dir.h>
     86 #include <ufs/ufs/ufs_bswap.h>
     87 #include <ufs/ffs/fs.h>
     88 #include <ufs/ffs/ffs_extern.h>
     89 #include <sys/ioctl.h>
     90 #include <sys/disklabel.h>
     91 
     92 #include <err.h>
     93 #include <errno.h>
     94 #include <string.h>
     95 #include <unistd.h>
     96 #include <stdlib.h>
     97 #include <stddef.h>
     98 
     99 #ifndef STANDALONE
    100 #include <stdio.h>
    101 #endif
    102 
    103 #include "extern.h"
    104 
    105 union dinode {
    106 	struct ufs1_dinode dp1;
    107 	struct ufs2_dinode dp2;
    108 };
    109 
    110 static void initcg(int, const struct timeval *);
    111 static int fsinit(const struct timeval *, mode_t, uid_t, gid_t);
    112 static int makedir(struct direct *, int);
    113 static daddr_t alloc(int, int);
    114 static void iput(union dinode *, ino_t);
    115 static void rdfs(daddr_t, int, void *);
    116 static void wtfs(daddr_t, int, void *);
    117 static int isblock(struct fs *, unsigned char *, int);
    118 static void clrblock(struct fs *, unsigned char *, int);
    119 static void setblock(struct fs *, unsigned char *, int);
    120 static int ilog2(int);
    121 static void zap_old_sblock(int);
    122 #ifdef MFS
    123 static void calc_memfree(void);
    124 static void *mkfs_malloc(size_t size);
    125 #endif
    126 
    127 /*
    128  * make file system for cylinder-group style file systems
    129  */
    130 #define	UMASK		0755
    131 #define	POWEROF2(num)	(((num) & ((num) - 1)) == 0)
    132 
    133 union {
    134 	struct fs fs;
    135 	char pad[SBLOCKSIZE];
    136 } fsun;
    137 #define	sblock	fsun.fs
    138 
    139 struct	csum *fscs_0;		/* first block of cylinder summaries */
    140 struct	csum *fscs_next;	/* place for next summary */
    141 struct	csum *fscs_end;		/* end of summary buffer */
    142 struct	csum *fscs_reset;	/* place for next summary after write */
    143 uint	fs_csaddr;		/* fragment number to write to */
    144 
    145 union {
    146 	struct cg cg;
    147 	char pad[MAXBSIZE];
    148 } cgun;
    149 #define	acg	cgun.cg
    150 
    151 #define DIP(dp, field) \
    152 	((sblock.fs_magic == FS_UFS1_MAGIC) ? \
    153 	(dp)->dp1.di_##field : (dp)->dp2.di_##field)
    154 
    155 char *iobuf;
    156 int iobufsize;			/* size to end of 2nd inode block */
    157 int iobuf_memsize;		/* Actual buffer size */
    158 
    159 int	fsi, fso;
    160 
    161 void
    162 mkfs(struct partition *pp, const char *fsys, int fi, int fo,
    163     mode_t mfsmode, uid_t mfsuid, gid_t mfsgid)
    164 {
    165 	uint fragsperinodeblk, ncg;
    166 	uint cgzero;
    167 	uint64_t inodeblks, cgall;
    168 	int32_t cylno, i, csfrags;
    169 	int inodes_per_cg;
    170 	struct timeval tv;
    171 	long long sizepb;
    172 	int len, col, delta, fld_width, max_cols;
    173 	struct winsize winsize;
    174 
    175 #ifndef STANDALONE
    176 	gettimeofday(&tv, NULL);
    177 #endif
    178 #ifdef MFS
    179 	if (mfs && !Nflag) {
    180 		calc_memfree();
    181 		if (fssize * sectorsize > memleft)
    182 			fssize = memleft / sectorsize;
    183 		if ((membase = mkfs_malloc(fssize * sectorsize)) == 0)
    184 			exit(12);
    185 	}
    186 #endif
    187 	fsi = fi;
    188 	fso = fo;
    189 	if (Oflag == 0) {
    190 		sblock.fs_old_inodefmt = FS_42INODEFMT;
    191 		sblock.fs_maxsymlinklen = 0;
    192 		sblock.fs_old_flags = 0;
    193 	} else {
    194 		sblock.fs_old_inodefmt = FS_44INODEFMT;
    195 		sblock.fs_maxsymlinklen = (Oflag == 1 ? MAXSYMLINKLEN_UFS1 :
    196 		    MAXSYMLINKLEN_UFS2);
    197 		sblock.fs_old_flags = FS_FLAGS_UPDATED;
    198 		if (isappleufs)
    199 			sblock.fs_old_flags = 0;
    200 		sblock.fs_flags = 0;
    201 	}
    202 
    203 	/*
    204 	 * collect and verify the filesystem density info
    205 	 */
    206 	sblock.fs_avgfilesize = avgfilesize;
    207 	sblock.fs_avgfpdir = avgfpdir;
    208 	if (sblock.fs_avgfilesize <= 0) {
    209 		printf("illegal expected average file size %d\n",
    210 		    sblock.fs_avgfilesize);
    211 		exit(14);
    212 	}
    213 	if (sblock.fs_avgfpdir <= 0) {
    214 		printf("illegal expected number of files per directory %d\n",
    215 		    sblock.fs_avgfpdir);
    216 		exit(15);
    217 	}
    218 	/*
    219 	 * collect and verify the block and fragment sizes
    220 	 */
    221 	sblock.fs_bsize = bsize;
    222 	sblock.fs_fsize = fsize;
    223 	if (!POWEROF2(sblock.fs_bsize)) {
    224 		printf("block size must be a power of 2, not %d\n",
    225 		    sblock.fs_bsize);
    226 		exit(16);
    227 	}
    228 	if (!POWEROF2(sblock.fs_fsize)) {
    229 		printf("fragment size must be a power of 2, not %d\n",
    230 		    sblock.fs_fsize);
    231 		exit(17);
    232 	}
    233 	if (sblock.fs_fsize < sectorsize) {
    234 		printf("fragment size %d is too small, minimum is %d\n",
    235 		    sblock.fs_fsize, sectorsize);
    236 		exit(18);
    237 	}
    238 	if (sblock.fs_bsize < MINBSIZE) {
    239 		printf("block size %d is too small, minimum is %d\n",
    240 		    sblock.fs_bsize, MINBSIZE);
    241 		exit(19);
    242 	}
    243 	if (sblock.fs_bsize > MAXBSIZE) {
    244 		printf("block size %d is too large, maximum is %d\n",
    245 		    sblock.fs_bsize, MAXBSIZE);
    246 		exit(19);
    247 	}
    248 	if (sblock.fs_bsize < sblock.fs_fsize) {
    249 		printf("block size (%d) cannot be smaller than fragment size (%d)\n",
    250 		    sblock.fs_bsize, sblock.fs_fsize);
    251 		exit(20);
    252 	}
    253 
    254 	if (maxbsize < bsize || !POWEROF2(maxbsize)) {
    255 		sblock.fs_maxbsize = sblock.fs_bsize;
    256 	} else if (sblock.fs_maxbsize > FS_MAXCONTIG * sblock.fs_bsize) {
    257 		sblock.fs_maxbsize = FS_MAXCONTIG * sblock.fs_bsize;
    258 	} else {
    259 		sblock.fs_maxbsize = maxbsize;
    260 	}
    261 	sblock.fs_maxcontig = maxcontig;
    262 	if (sblock.fs_maxcontig < sblock.fs_maxbsize / sblock.fs_bsize) {
    263 		sblock.fs_maxcontig = sblock.fs_maxbsize / sblock.fs_bsize;
    264 		if (verbosity > 0)
    265 			printf("Maxcontig raised to %d\n", sblock.fs_maxbsize);
    266 	}
    267 	if (sblock.fs_maxcontig > 1)
    268 		sblock.fs_contigsumsize = MIN(sblock.fs_maxcontig,FS_MAXCONTIG);
    269 
    270 	sblock.fs_bmask = ~(sblock.fs_bsize - 1);
    271 	sblock.fs_fmask = ~(sblock.fs_fsize - 1);
    272 	sblock.fs_qbmask = ~sblock.fs_bmask;
    273 	sblock.fs_qfmask = ~sblock.fs_fmask;
    274 	for (sblock.fs_bshift = 0, i = sblock.fs_bsize; i > 1; i >>= 1)
    275 		sblock.fs_bshift++;
    276 	for (sblock.fs_fshift = 0, i = sblock.fs_fsize; i > 1; i >>= 1)
    277 		sblock.fs_fshift++;
    278 	sblock.fs_frag = numfrags(&sblock, sblock.fs_bsize);
    279 	for (sblock.fs_fragshift = 0, i = sblock.fs_frag; i > 1; i >>= 1)
    280 		sblock.fs_fragshift++;
    281 	if (sblock.fs_frag > MAXFRAG) {
    282 		printf("fragment size %d is too small, "
    283 			"minimum with block size %d is %d\n",
    284 		    sblock.fs_fsize, sblock.fs_bsize,
    285 		    sblock.fs_bsize / MAXFRAG);
    286 		exit(21);
    287 	}
    288 	sblock.fs_fsbtodb = ilog2(sblock.fs_fsize / sectorsize);
    289 	sblock.fs_size = dbtofsb(&sblock, fssize);
    290 	if (Oflag <= 1) {
    291 		if (sblock.fs_size >= 1ull << 31) {
    292 			printf("Too many fragments (0x%" PRIx64
    293 			    ") for a UFS1 filesystem\n", sblock.fs_size);
    294 			exit(22);
    295 		}
    296 		sblock.fs_magic = FS_UFS1_MAGIC;
    297 		sblock.fs_sblockloc = SBLOCK_UFS1;
    298 		sblock.fs_nindir = sblock.fs_bsize / sizeof(int32_t);
    299 		sblock.fs_inopb = sblock.fs_bsize / sizeof(struct ufs1_dinode);
    300 		sblock.fs_old_cgoffset = 0;
    301 		sblock.fs_old_cgmask = 0xffffffff;
    302 		sblock.fs_old_size = sblock.fs_size;
    303 		sblock.fs_old_rotdelay = 0;
    304 		sblock.fs_old_rps = 60;
    305 		sblock.fs_old_nspf = sblock.fs_fsize / sectorsize;
    306 		sblock.fs_old_cpg = 1;
    307 		sblock.fs_old_interleave = 1;
    308 		sblock.fs_old_trackskew = 0;
    309 		sblock.fs_old_cpc = 0;
    310 		sblock.fs_old_postblformat = FS_DYNAMICPOSTBLFMT;
    311 		sblock.fs_old_nrpos = 1;
    312 	} else {
    313 		sblock.fs_magic = FS_UFS2_MAGIC;
    314 		sblock.fs_sblockloc = SBLOCK_UFS2;
    315 		sblock.fs_nindir = sblock.fs_bsize / sizeof(int64_t);
    316 		sblock.fs_inopb = sblock.fs_bsize / sizeof(struct ufs2_dinode);
    317 	}
    318 
    319 	sblock.fs_sblkno =
    320 	    roundup(howmany(sblock.fs_sblockloc + SBLOCKSIZE, sblock.fs_fsize),
    321 		sblock.fs_frag);
    322 	sblock.fs_cblkno = (daddr_t)(sblock.fs_sblkno +
    323 	    roundup(howmany(SBLOCKSIZE, sblock.fs_fsize), sblock.fs_frag));
    324 	sblock.fs_iblkno = sblock.fs_cblkno + sblock.fs_frag;
    325 	sblock.fs_maxfilesize = sblock.fs_bsize * NDADDR - 1;
    326 	for (sizepb = sblock.fs_bsize, i = 0; i < NIADDR; i++) {
    327 		sizepb *= NINDIR(&sblock);
    328 		sblock.fs_maxfilesize += sizepb;
    329 	}
    330 
    331 	/*
    332 	 * Calculate the number of blocks to put into each cylinder group.
    333 	 *
    334 	 * The cylinder group size is limited because the data structure
    335 	 * must fit into a single block.
    336 	 * We try to have as few cylinder groups as possible, with a proviso
    337 	 * that we create at least MINCYLGRPS (==4) except for small
    338 	 * filesystems.
    339 	 *
    340 	 * This algorithm works out how many blocks of inodes would be
    341 	 * needed to fill the entire volume at the specified density.
    342 	 * It then looks at how big the 'cylinder block' would have to
    343 	 * be and, assuming that it is linearly related to the number
    344 	 * of inodes and blocks how many cylinder groups are needed to
    345 	 * keep the cylinder block below the filesystem block size.
    346 	 *
    347 	 * The cylinder groups are then all created with the average size.
    348 	 *
    349 	 * Space taken by the red tape on cylinder groups other than the
    350 	 * first is ignored.
    351 	 */
    352 
    353 	/* There must be space for 1 inode block and 2 data blocks */
    354 	if (sblock.fs_size < sblock.fs_iblkno + 3 * sblock.fs_frag) {
    355 		printf("Filesystem size %lld < minimum size of %d\n",
    356 		    (long long)sblock.fs_size, sblock.fs_iblkno + 3 * sblock.fs_frag);
    357 		exit(23);
    358 	}
    359 	if (num_inodes != 0)
    360 		inodeblks = howmany(num_inodes, INOPB(&sblock));
    361 	else {
    362 		/*
    363 		 * Calculate 'per inode block' so we can allocate less than
    364 		 * 1 fragment per inode - useful for /dev.
    365 		 */
    366 		fragsperinodeblk = MAX(numfrags(&sblock,
    367 					density * INOPB(&sblock)), 1);
    368 		inodeblks = (sblock.fs_size - sblock.fs_iblkno) /
    369 			(sblock.fs_frag + fragsperinodeblk);
    370 	}
    371 	if (inodeblks == 0)
    372 		inodeblks = 1;
    373 	/* Ensure that there are at least 2 data blocks (or we fail below) */
    374 	if (inodeblks > (sblock.fs_size - sblock.fs_iblkno)/sblock.fs_frag - 2)
    375 		inodeblks = (sblock.fs_size-sblock.fs_iblkno)/sblock.fs_frag-2;
    376 	/* Even UFS2 limits number of inodes to 2^31 (fs_ipg is int32_t) */
    377 	if (inodeblks * INOPB(&sblock) >= 1ull << 31)
    378 		inodeblks = ((1ull << 31) - NBBY) / INOPB(&sblock);
    379 	/*
    380 	 * See what would happen if we tried to use 1 cylinder group.
    381 	 * Assume space linear, so work out number of cylinder groups needed.
    382 	 */
    383 	cgzero = CGSIZE_IF(&sblock, 0, 0);
    384 	cgall = CGSIZE_IF(&sblock, inodeblks * INOPB(&sblock), sblock.fs_size);
    385 	ncg = howmany(cgall - cgzero, sblock.fs_bsize - cgzero);
    386 	if (ncg < MINCYLGRPS) {
    387 		/*
    388 		 * We would like to allocate MINCLYGRPS cylinder groups,
    389 		 * but for small file sytems (especially ones with a lot
    390 		 * of inodes) this is not desirable (or possible).
    391 		 */
    392 		i = sblock.fs_size / 2 / (sblock.fs_iblkno +
    393 						inodeblks * sblock.fs_frag);
    394 		if (i > ncg)
    395 			ncg = i;
    396 		if (ncg > MINCYLGRPS)
    397 			ncg = MINCYLGRPS;
    398 		if (ncg > inodeblks)
    399 			ncg = inodeblks;
    400 	}
    401 	/*
    402 	 * Put an equal number of blocks in each cylinder group.
    403 	 * Round up so we don't have more fragments in the last CG than
    404 	 * the earlier ones (does that matter?), but kill a block if the
    405 	 * CGSIZE becomes too big (only happens if there are a lot of CGs).
    406 	 */
    407 	sblock.fs_fpg = roundup(howmany(sblock.fs_size, ncg), sblock.fs_frag);
    408 	/* Round up the fragments/group so the bitmap bytes are full */
    409 	sblock.fs_fpg = roundup(sblock.fs_fpg, NBBY);
    410 	inodes_per_cg = ((inodeblks - 1) / ncg + 1) * INOPB(&sblock);
    411 
    412 	i = CGSIZE_IF(&sblock, inodes_per_cg, sblock.fs_fpg);
    413 	if (i > sblock.fs_bsize) {
    414 		sblock.fs_fpg -= (i - sblock.fs_bsize) * NBBY;
    415 		/* ... and recalculate how many cylinder groups we now need */
    416 		ncg = howmany(sblock.fs_size, sblock.fs_fpg);
    417 		inodes_per_cg = ((inodeblks - 1) / ncg + 1) * INOPB(&sblock);
    418 	}
    419 	sblock.fs_ipg = inodes_per_cg;
    420 	/* Sanity check on our sums... */
    421 	if (CGSIZE(&sblock) > sblock.fs_bsize) {
    422 		printf("CGSIZE miscalculated %d > %d\n",
    423 		    (int)CGSIZE(&sblock), sblock.fs_bsize);
    424 		exit(24);
    425 	}
    426 
    427 	sblock.fs_dblkno = sblock.fs_iblkno + sblock.fs_ipg / INOPF(&sblock);
    428 	/* Check that the last cylinder group has enough space for the inodes */
    429 	i = sblock.fs_size - sblock.fs_fpg * (ncg - 1ull);
    430 	if (i < sblock.fs_dblkno) {
    431 		/*
    432 		 * Since we make all the cylinder groups the same size, the
    433 		 * last will only be small if there are a large number of
    434 		 * cylinder groups. If we pull even a fragment from each
    435 		 * of the other groups then the last CG will be overfull.
    436 		 * So we just kill the last CG.
    437 		 */
    438 		ncg--;
    439 		sblock.fs_size -= i;
    440 	}
    441 	sblock.fs_ncg = ncg;
    442 
    443 	sblock.fs_cgsize = fragroundup(&sblock, CGSIZE(&sblock));
    444 	if (Oflag <= 1) {
    445 		sblock.fs_old_spc = sblock.fs_fpg * sblock.fs_old_nspf;
    446 		sblock.fs_old_nsect = sblock.fs_old_spc;
    447 		sblock.fs_old_npsect = sblock.fs_old_spc;
    448 		sblock.fs_old_ncyl = sblock.fs_ncg;
    449 	}
    450 
    451 	/*
    452 	 * Cylinder group summary information for each cylinder is written
    453 	 * into the first cylinder group.
    454 	 * Write this fragment by fragment, but doing the first CG last
    455 	 * (after we've taken stuff off for the structure itself and the
    456 	 * root directory.
    457 	 */
    458 	sblock.fs_csaddr = cgdmin(&sblock, 0);
    459 	sblock.fs_cssize =
    460 	    fragroundup(&sblock, sblock.fs_ncg * sizeof(struct csum));
    461 	if (512 % sizeof *fscs_0)
    462 		errx(1, "cylinder group summary doesn't fit in sectors");
    463 	fscs_0 = mmap(0, 2 * sblock.fs_fsize, PROT_READ|PROT_WRITE,
    464 			MAP_ANON|MAP_PRIVATE, -1, 0);
    465 	if (fscs_0 == NULL)
    466 		exit(39);
    467 	memset(fscs_0, 0, 2 * sblock.fs_fsize);
    468 	fs_csaddr = sblock.fs_csaddr;
    469 	fscs_next = fscs_0;
    470 	fscs_end = (void *)((char *)fscs_0 + 2 * sblock.fs_fsize);
    471 	fscs_reset = (void *)((char *)fscs_0 + sblock.fs_fsize);
    472 	/*
    473 	 * fill in remaining fields of the super block
    474 	 */
    475 	sblock.fs_sbsize = fragroundup(&sblock, sizeof(struct fs));
    476 	if (sblock.fs_sbsize > SBLOCKSIZE)
    477 		sblock.fs_sbsize = SBLOCKSIZE;
    478 	sblock.fs_minfree = minfree;
    479 	sblock.fs_maxcontig = maxcontig;
    480 	sblock.fs_maxbpg = maxbpg;
    481 	sblock.fs_optim = opt;
    482 	sblock.fs_cgrotor = 0;
    483 	sblock.fs_pendingblocks = 0;
    484 	sblock.fs_pendinginodes = 0;
    485 	sblock.fs_cstotal.cs_ndir = 0;
    486 	sblock.fs_cstotal.cs_nbfree = 0;
    487 	sblock.fs_cstotal.cs_nifree = 0;
    488 	sblock.fs_cstotal.cs_nffree = 0;
    489 	sblock.fs_fmod = 0;
    490 	sblock.fs_ronly = 0;
    491 	sblock.fs_state = 0;
    492 	sblock.fs_clean = FS_ISCLEAN;
    493 	sblock.fs_ronly = 0;
    494 	sblock.fs_id[0] = (long)tv.tv_sec;	/* XXXfvdl huh? */
    495 	sblock.fs_id[1] = arc4random() & INT32_MAX;
    496 	sblock.fs_fsmnt[0] = '\0';
    497 	csfrags = howmany(sblock.fs_cssize, sblock.fs_fsize);
    498 	sblock.fs_dsize = sblock.fs_size - sblock.fs_sblkno -
    499 	    sblock.fs_ncg * (sblock.fs_dblkno - sblock.fs_sblkno);
    500 	sblock.fs_cstotal.cs_nbfree =
    501 	    fragstoblks(&sblock, sblock.fs_dsize) -
    502 	    howmany(csfrags, sblock.fs_frag);
    503 	sblock.fs_cstotal.cs_nffree =
    504 	    fragnum(&sblock, sblock.fs_size) +
    505 	    (fragnum(&sblock, csfrags) > 0 ?
    506 	    sblock.fs_frag - fragnum(&sblock, csfrags) : 0);
    507 	sblock.fs_cstotal.cs_nifree = sblock.fs_ncg * sblock.fs_ipg - ROOTINO;
    508 	sblock.fs_cstotal.cs_ndir = 0;
    509 	sblock.fs_dsize -= csfrags;
    510 	sblock.fs_time = tv.tv_sec;
    511 	if (Oflag <= 1) {
    512 		sblock.fs_old_time = tv.tv_sec;
    513 		sblock.fs_old_dsize = sblock.fs_dsize;
    514 		sblock.fs_old_csaddr = sblock.fs_csaddr;
    515 		sblock.fs_old_cstotal.cs_ndir = sblock.fs_cstotal.cs_ndir;
    516 		sblock.fs_old_cstotal.cs_nbfree = sblock.fs_cstotal.cs_nbfree;
    517 		sblock.fs_old_cstotal.cs_nifree = sblock.fs_cstotal.cs_nifree;
    518 		sblock.fs_old_cstotal.cs_nffree = sblock.fs_cstotal.cs_nffree;
    519 	}
    520 	/*
    521 	 * Dump out summary information about file system.
    522 	 */
    523 	if (verbosity > 0) {
    524 #define	B2MBFACTOR (1 / (1024.0 * 1024.0))
    525 		printf("%s: %.1fMB (%lld sectors) block size %d, "
    526 		       "fragment size %d\n",
    527 		    fsys, (float)sblock.fs_size * sblock.fs_fsize * B2MBFACTOR,
    528 		    (long long)fsbtodb(&sblock, sblock.fs_size),
    529 		    sblock.fs_bsize, sblock.fs_fsize);
    530 		printf("\tusing %d cylinder groups of %.2fMB, %d blks, "
    531 		       "%d inodes.\n",
    532 		    sblock.fs_ncg,
    533 		    (float)sblock.fs_fpg * sblock.fs_fsize * B2MBFACTOR,
    534 		    sblock.fs_fpg / sblock.fs_frag, sblock.fs_ipg);
    535 #undef B2MBFACTOR
    536 	}
    537 
    538 	/*
    539 	 * allocate space for superblock, cylinder group map, and
    540 	 * two sets of inode blocks.
    541 	 */
    542 	if (sblock.fs_bsize < SBLOCKSIZE)
    543 		iobufsize = SBLOCKSIZE + 3 * sblock.fs_bsize;
    544 	else
    545 		iobufsize = 4 * sblock.fs_bsize;
    546 	iobuf_memsize = iobufsize;
    547 	if (!mfs && sblock.fs_magic == FS_UFS1_MAGIC) {
    548 		/* A larger buffer so we can write multiple inode blks */
    549 		iobuf_memsize += 14 * sblock.fs_bsize;
    550 	}
    551 	for (;;) {
    552 		iobuf = mmap(0, iobuf_memsize, PROT_READ|PROT_WRITE,
    553 				MAP_ANON|MAP_PRIVATE, -1, 0);
    554 		if (iobuf != NULL)
    555 			break;
    556 		if (iobuf_memsize != iobufsize) {
    557 			/* Try again with the smaller size */
    558 			iobuf_memsize = iobufsize;
    559 			continue;
    560 		}
    561 		printf("Cannot allocate I/O buffer\n");
    562 		exit(38);
    563 	}
    564 	memset(iobuf, 0, iobuf_memsize);
    565 
    566 	/*
    567 	 * We now start writing to the filesystem
    568 	 */
    569 
    570 	if (!Nflag) {
    571 		/*
    572 		 * Validate the given file system size.
    573 		 * Verify that its last block can actually be accessed.
    574 		 * Convert to file system fragment sized units.
    575 		 */
    576 		if (fssize <= 0) {
    577 			printf("preposterous size %lld\n", (long long)fssize);
    578 			exit(13);
    579 		}
    580 		wtfs(fssize - 1, sectorsize, iobuf);
    581 
    582 		/*
    583 		 * Ensure there is nothing that looks like a filesystem
    584 		 * superbock anywhere other than where ours will be.
    585 		 * If fsck finds the wrong one all hell breaks loose!
    586 		 */
    587 		for (i = 0; ; i++) {
    588 			static const int sblocklist[] = SBLOCKSEARCH;
    589 			int sblkoff = sblocklist[i];
    590 			int sz;
    591 			if (sblkoff == -1)
    592 				break;
    593 			/* Remove main superblock */
    594 			zap_old_sblock(sblkoff);
    595 			/* and all possible locations for the first alternate */
    596 			sblkoff += SBLOCKSIZE;
    597 			for (sz = SBLOCKSIZE; sz <= 0x10000; sz <<= 1)
    598 				zap_old_sblock(roundup(sblkoff, sz));
    599 		}
    600 
    601 		if (isappleufs) {
    602 			struct appleufslabel appleufs;
    603 			ffs_appleufs_set(&appleufs, appleufs_volname,
    604 			    tv.tv_sec, 0);
    605 			wtfs(APPLEUFS_LABEL_OFFSET/sectorsize,
    606 			    APPLEUFS_LABEL_SIZE, &appleufs);
    607 		} else {
    608 			struct appleufslabel appleufs;
    609 			/* Look for & zap any existing valid apple ufs labels */
    610 			rdfs(APPLEUFS_LABEL_OFFSET/sectorsize,
    611 			    APPLEUFS_LABEL_SIZE, &appleufs);
    612 			if (ffs_appleufs_validate(fsys, &appleufs, NULL) == 0) {
    613 				memset(&appleufs, 0, sizeof(appleufs));
    614 				wtfs(APPLEUFS_LABEL_OFFSET/sectorsize,
    615 				    APPLEUFS_LABEL_SIZE, &appleufs);
    616 			}
    617 		}
    618 	}
    619 
    620 	/*
    621 	 * Make a copy of the superblock into the buffer that we will be
    622 	 * writing out in each cylinder group.
    623 	 */
    624 	memcpy(iobuf, &sblock, sizeof sblock);
    625 	if (needswap)
    626 		ffs_sb_swap(&sblock, (struct fs *)iobuf);
    627 	if ((sblock.fs_old_flags & FS_FLAGS_UPDATED) == 0)
    628 		memset(iobuf + offsetof(struct fs, fs_old_postbl_start),
    629 		    0xff, 256);
    630 
    631 	if (verbosity >= 3)
    632 		printf("super-block backups (for fsck_ffs -b #) at:\n");
    633 	/* If we are printing more than one line of numbers, line up columns */
    634 	fld_width = verbosity < 4 ? 1 : snprintf(NULL, 0, "%" PRIu64,
    635 		(uint64_t)fsbtodb(&sblock, cgsblock(&sblock, sblock.fs_ncg-1)));
    636 	/* Get terminal width */
    637 	if (ioctl(fileno(stdout), TIOCGWINSZ, &winsize) == 0)
    638 		max_cols = winsize.ws_col;
    639 	else
    640 		max_cols = 80;
    641 	if (Nflag && verbosity == 3)
    642 		/* Leave space to add " ..." after one row of numbers */
    643 		max_cols -= 4;
    644 #define BASE 0x10000	/* For some fixed-point maths */
    645 	col = 0;
    646 	delta = verbosity > 2 ? 0 : max_cols * BASE / sblock.fs_ncg;
    647 	for (cylno = 0; cylno < sblock.fs_ncg; cylno++) {
    648 		fflush(stdout);
    649 		initcg(cylno, &tv);
    650 		if (verbosity < 2)
    651 			continue;
    652 		if (delta > 0) {
    653 			if (Nflag)
    654 				/* No point doing dots for -N */
    655 				break;
    656 			/* Print dots scaled to end near RH margin */
    657 			for (col += delta; col > BASE; col -= BASE)
    658 				printf(".");
    659 			continue;
    660 		}
    661 		/* Print superblock numbers */
    662 		len = printf(" %*" PRIu64 "," + !col, fld_width,
    663 		    (uint64_t)fsbtodb(&sblock, cgsblock(&sblock, cylno)));
    664 		col += len;
    665 		if (col + len < max_cols)
    666 			/* Next number fits */
    667 			continue;
    668 		/* Next number won't fit, need a newline */
    669 		if (verbosity <= 3) {
    670 			/* Print dots for subsequent cylinder groups */
    671 			delta = sblock.fs_ncg - cylno - 1;
    672 			if (delta != 0) {
    673 				if (Nflag) {
    674 					printf(" ...");
    675 					break;
    676 				}
    677 				delta = max_cols * BASE / delta;
    678 			}
    679 		}
    680 		col = 0;
    681 		printf("\n");
    682 	}
    683 #undef BASE
    684 	if (col > 0)
    685 		printf("\n");
    686 	if (Nflag)
    687 		exit(0);
    688 
    689 	/*
    690 	 * Now construct the initial file system,
    691 	 */
    692 	if (fsinit(&tv, mfsmode, mfsuid, mfsgid) == 0 && mfs)
    693 		errx(1, "Error making filesystem");
    694 	sblock.fs_time = tv.tv_sec;
    695 	if (Oflag <= 1) {
    696 		sblock.fs_old_cstotal.cs_ndir = sblock.fs_cstotal.cs_ndir;
    697 		sblock.fs_old_cstotal.cs_nbfree = sblock.fs_cstotal.cs_nbfree;
    698 		sblock.fs_old_cstotal.cs_nifree = sblock.fs_cstotal.cs_nifree;
    699 		sblock.fs_old_cstotal.cs_nffree = sblock.fs_cstotal.cs_nffree;
    700 	}
    701 	/*
    702 	 * Write out the super-block and zeros until the first cg info
    703 	 */
    704 	i = cgsblock(&sblock, 0) * sblock.fs_fsize - sblock.fs_sblockloc,
    705 	memset(iobuf, 0, i);
    706 	memcpy(iobuf, &sblock, sizeof sblock);
    707 	if (needswap)
    708 		ffs_sb_swap(&sblock, (struct fs *)iobuf);
    709 	if ((sblock.fs_old_flags & FS_FLAGS_UPDATED) == 0)
    710 		memset(iobuf + offsetof(struct fs, fs_old_postbl_start),
    711 		    0xff, 256);
    712 	wtfs(sblock.fs_sblockloc / sectorsize, i, iobuf);
    713 
    714 	/* Write out first and last cylinder summary sectors */
    715 	if (needswap)
    716 		ffs_csum_swap(fscs_0, fscs_0, sblock.fs_fsize);
    717 	wtfs(fsbtodb(&sblock, sblock.fs_csaddr), sblock.fs_fsize, fscs_0);
    718 
    719 	if (fscs_next > fscs_reset) {
    720 		if (needswap)
    721 			ffs_csum_swap(fscs_reset, fscs_reset, sblock.fs_fsize);
    722 		fs_csaddr++;
    723 		wtfs(fsbtodb(&sblock, fs_csaddr), sblock.fs_fsize, fscs_reset);
    724 	}
    725 
    726 	/* mfs doesn't need these permanently allocated */
    727 	munmap(iobuf, iobuf_memsize);
    728 	munmap(fscs_0, 2 * sblock.fs_fsize);
    729 
    730 	/*
    731 	 * Update information about this partion in pack
    732 	 * label, to that it may be updated on disk.
    733 	 */
    734 	if (pp == NULL)
    735 		return;
    736 	if (isappleufs)
    737 		pp->p_fstype = FS_APPLEUFS;
    738 	else
    739 		pp->p_fstype = FS_BSDFFS;
    740 	pp->p_fsize = sblock.fs_fsize;
    741 	pp->p_frag = sblock.fs_frag;
    742 	pp->p_cpg = sblock.fs_fpg;
    743 }
    744 
    745 /*
    746  * Initialize a cylinder group.
    747  */
    748 void
    749 initcg(int cylno, const struct timeval *tv)
    750 {
    751 	daddr_t cbase, dmax;
    752 	int32_t i, d, dlower, dupper, blkno;
    753 	struct ufs1_dinode *dp1;
    754 	struct ufs2_dinode *dp2;
    755 	int start;
    756 
    757 	/*
    758 	 * Determine block bounds for cylinder group.
    759 	 * Allow space for super block summary information in first
    760 	 * cylinder group.
    761 	 */
    762 	cbase = cgbase(&sblock, cylno);
    763 	dmax = cbase + sblock.fs_fpg;
    764 	if (dmax > sblock.fs_size)
    765 		dmax = sblock.fs_size;
    766 	dlower = cgsblock(&sblock, cylno) - cbase;
    767 	dupper = cgdmin(&sblock, cylno) - cbase;
    768 	if (cylno == 0) {
    769 		dupper += howmany(sblock.fs_cssize, sblock.fs_fsize);
    770 		if (dupper >= cgstart(&sblock, cylno + 1)) {
    771 			printf("\rToo many cylinder groups to fit summary "
    772 				"information into first cylinder group\n");
    773 			exit(40);
    774 		}
    775 	}
    776 	memset(&acg, 0, sblock.fs_cgsize);
    777 	acg.cg_magic = CG_MAGIC;
    778 	acg.cg_cgx = cylno;
    779 	acg.cg_ndblk = dmax - cbase;
    780 	if (sblock.fs_contigsumsize > 0)
    781 		acg.cg_nclusterblks = acg.cg_ndblk >> sblock.fs_fragshift;
    782 	start = &acg.cg_space[0] - (u_char *)(&acg.cg_firstfield);
    783 	if (Oflag == 2) {
    784 		acg.cg_time = tv->tv_sec;
    785 		acg.cg_niblk = sblock.fs_ipg;
    786 		acg.cg_initediblk = sblock.fs_ipg < 2 * INOPB(&sblock) ?
    787 		    sblock.fs_ipg : 2 * INOPB(&sblock);
    788 		acg.cg_iusedoff = start;
    789 	} else {
    790 		acg.cg_old_ncyl = sblock.fs_old_cpg;
    791 		if ((sblock.fs_old_flags & FS_FLAGS_UPDATED) == 0 &&
    792 		    (cylno == sblock.fs_ncg - 1))
    793 			acg.cg_old_ncyl =
    794 			    sblock.fs_old_ncyl % sblock.fs_old_cpg;
    795 		acg.cg_old_time = tv->tv_sec;
    796 		acg.cg_old_niblk = sblock.fs_ipg;
    797 		acg.cg_old_btotoff = start;
    798 		acg.cg_old_boff = acg.cg_old_btotoff +
    799 		    sblock.fs_old_cpg * sizeof(int32_t);
    800 		acg.cg_iusedoff = acg.cg_old_boff +
    801 		    sblock.fs_old_cpg * sizeof(u_int16_t);
    802 	}
    803 	acg.cg_freeoff = acg.cg_iusedoff + howmany(sblock.fs_ipg, CHAR_BIT);
    804 	if (sblock.fs_contigsumsize <= 0) {
    805 		acg.cg_nextfreeoff = acg.cg_freeoff +
    806 		   howmany(sblock.fs_fpg, CHAR_BIT);
    807 	} else {
    808 		acg.cg_clustersumoff = acg.cg_freeoff +
    809 		    howmany(sblock.fs_fpg, CHAR_BIT) - sizeof(int32_t);
    810 		if (isappleufs) {
    811 			/* Apple PR2216969 gives rationale for this change.
    812 			 * I believe they were mistaken, but we need to
    813 			 * duplicate it for compatibility.  -- dbj (at) NetBSD.org
    814 			 */
    815 			acg.cg_clustersumoff += sizeof(int32_t);
    816 		}
    817 		acg.cg_clustersumoff =
    818 		    roundup(acg.cg_clustersumoff, sizeof(int32_t));
    819 		acg.cg_clusteroff = acg.cg_clustersumoff +
    820 		    (sblock.fs_contigsumsize + 1) * sizeof(int32_t);
    821 		acg.cg_nextfreeoff = acg.cg_clusteroff +
    822 		    howmany(fragstoblks(&sblock, sblock.fs_fpg), CHAR_BIT);
    823 	}
    824 	if (acg.cg_nextfreeoff > sblock.fs_cgsize) {
    825 		printf("Panic: cylinder group too big\n");
    826 		exit(37);
    827 	}
    828 	acg.cg_cs.cs_nifree += sblock.fs_ipg;
    829 	if (cylno == 0)
    830 		for (i = 0; i < ROOTINO; i++) {
    831 			setbit(cg_inosused(&acg, 0), i);
    832 			acg.cg_cs.cs_nifree--;
    833 		}
    834 	if (cylno > 0) {
    835 		/*
    836 		 * In cylno 0, beginning space is reserved
    837 		 * for boot and super blocks.
    838 		 */
    839 		for (d = 0, blkno = 0; d < dlower;) {
    840 			setblock(&sblock, cg_blksfree(&acg, 0), blkno);
    841 			if (sblock.fs_contigsumsize > 0)
    842 				setbit(cg_clustersfree(&acg, 0), blkno);
    843 			acg.cg_cs.cs_nbfree++;
    844 			if (Oflag <= 1) {
    845 				int cn = old_cbtocylno(&sblock, d);
    846 				old_cg_blktot(&acg, 0)[cn]++;
    847 				old_cg_blks(&sblock, &acg,
    848 				    cn, 0)[old_cbtorpos(&sblock, d)]++;
    849 			}
    850 			d += sblock.fs_frag;
    851 			blkno++;
    852 		}
    853 	}
    854 	if ((i = (dupper & (sblock.fs_frag - 1))) != 0) {
    855 		acg.cg_frsum[sblock.fs_frag - i]++;
    856 		for (d = dupper + sblock.fs_frag - i; dupper < d; dupper++) {
    857 			setbit(cg_blksfree(&acg, 0), dupper);
    858 			acg.cg_cs.cs_nffree++;
    859 		}
    860 	}
    861 	for (d = dupper, blkno = dupper >> sblock.fs_fragshift;
    862 	     d + sblock.fs_frag <= acg.cg_ndblk; ) {
    863 		setblock(&sblock, cg_blksfree(&acg, 0), blkno);
    864 		if (sblock.fs_contigsumsize > 0)
    865 			setbit(cg_clustersfree(&acg, 0), blkno);
    866 		acg.cg_cs.cs_nbfree++;
    867 		if (Oflag <= 1) {
    868 			int cn = old_cbtocylno(&sblock, d);
    869 			old_cg_blktot(&acg, 0)[cn]++;
    870 			old_cg_blks(&sblock, &acg,
    871 			    cn, 0)[old_cbtorpos(&sblock, d)]++;
    872 		}
    873 		d += sblock.fs_frag;
    874 		blkno++;
    875 	}
    876 	if (d < acg.cg_ndblk) {
    877 		acg.cg_frsum[acg.cg_ndblk - d]++;
    878 		for (; d < acg.cg_ndblk; d++) {
    879 			setbit(cg_blksfree(&acg, 0), d);
    880 			acg.cg_cs.cs_nffree++;
    881 		}
    882 	}
    883 	if (sblock.fs_contigsumsize > 0) {
    884 		int32_t *sump = cg_clustersum(&acg, 0);
    885 		u_char *mapp = cg_clustersfree(&acg, 0);
    886 		int map = *mapp++;
    887 		int bit = 1;
    888 		int run = 0;
    889 
    890 		for (i = 0; i < acg.cg_nclusterblks; i++) {
    891 			if ((map & bit) != 0) {
    892 				run++;
    893 			} else if (run != 0) {
    894 				if (run > sblock.fs_contigsumsize)
    895 					run = sblock.fs_contigsumsize;
    896 				sump[run]++;
    897 				run = 0;
    898 			}
    899 			if ((i & (CHAR_BIT - 1)) != (CHAR_BIT - 1)) {
    900 				bit <<= 1;
    901 			} else {
    902 				map = *mapp++;
    903 				bit = 1;
    904 			}
    905 		}
    906 		if (run != 0) {
    907 			if (run > sblock.fs_contigsumsize)
    908 				run = sblock.fs_contigsumsize;
    909 			sump[run]++;
    910 		}
    911 	}
    912 	*fscs_next++ = acg.cg_cs;
    913 	if (fscs_next == fscs_end) {
    914 		/* write block of cylinder group summary info into cyl 0 */
    915 		if (needswap)
    916 			ffs_csum_swap(fscs_reset, fscs_reset, sblock.fs_fsize);
    917 		fs_csaddr++;
    918 		wtfs(fsbtodb(&sblock, fs_csaddr), sblock.fs_fsize, fscs_reset);
    919 		fscs_next = fscs_reset;
    920 		memset(fscs_next, 0, sblock.fs_fsize);
    921 	}
    922 	/*
    923 	 * Write out the duplicate super block, the cylinder group map
    924 	 * and two blocks worth of inodes in a single write.
    925 	 */
    926 	start = sblock.fs_bsize > SBLOCKSIZE ? sblock.fs_bsize : SBLOCKSIZE;
    927 	memcpy(&iobuf[start], &acg, sblock.fs_cgsize);
    928 	if (needswap)
    929 		ffs_cg_swap(&acg, (struct cg*)&iobuf[start], &sblock);
    930 	start += sblock.fs_bsize;
    931 	dp1 = (struct ufs1_dinode *)(&iobuf[start]);
    932 	dp2 = (struct ufs2_dinode *)(&iobuf[start]);
    933 	for (i = MIN(sblock.fs_ipg, 2) * INOPB(&sblock); i != 0; i--) {
    934 		if (sblock.fs_magic == FS_UFS1_MAGIC) {
    935 			/* No need to swap, it'll stay random */
    936 			dp1->di_gen = arc4random() & INT32_MAX;
    937 			dp1++;
    938 		} else {
    939 			dp2->di_gen = arc4random() & INT32_MAX;
    940 			dp2++;
    941 		}
    942 	}
    943 	wtfs(fsbtodb(&sblock, cgsblock(&sblock, cylno)), iobufsize, iobuf);
    944 	/*
    945 	 * For the old file system, we have to initialize all the inodes.
    946 	 */
    947 	if (sblock.fs_magic != FS_UFS1_MAGIC)
    948 		return;
    949 
    950 	/* Write 'd' (usually 16 * fs_frag) file-system fragments at once */
    951 	d = (iobuf_memsize - start) / sblock.fs_bsize * sblock.fs_frag;
    952 	dupper = sblock.fs_ipg / INOPF(&sblock);
    953 	for (i = 2 * sblock.fs_frag; i < dupper; i += d) {
    954 		if (d > dupper - i)
    955 			d = dupper - i;
    956 		dp1 = (struct ufs1_dinode *)(&iobuf[start]);
    957 		do
    958 			dp1->di_gen = arc4random() & INT32_MAX;
    959 		while ((char *)++dp1 < &iobuf[iobuf_memsize]);
    960 		wtfs(fsbtodb(&sblock, cgimin(&sblock, cylno) + i),
    961 		    d * sblock.fs_bsize / sblock.fs_frag, &iobuf[start]);
    962 	}
    963 }
    964 
    965 /*
    966  * initialize the file system
    967  */
    968 
    969 #ifdef LOSTDIR
    970 #define	PREDEFDIR 3
    971 #else
    972 #define	PREDEFDIR 2
    973 #endif
    974 
    975 struct direct root_dir[] = {
    976 	{ ROOTINO, sizeof(struct direct), DT_DIR, 1, "." },
    977 	{ ROOTINO, sizeof(struct direct), DT_DIR, 2, ".." },
    978 #ifdef LOSTDIR
    979 	{ LOSTFOUNDINO, sizeof(struct direct), DT_DIR, 10, "lost+found" },
    980 #endif
    981 };
    982 struct odirect {
    983 	u_int32_t d_ino;
    984 	u_int16_t d_reclen;
    985 	u_int16_t d_namlen;
    986 	u_char	d_name[FFS_MAXNAMLEN + 1];
    987 } oroot_dir[] = {
    988 	{ ROOTINO, sizeof(struct direct), 1, "." },
    989 	{ ROOTINO, sizeof(struct direct), 2, ".." },
    990 #ifdef LOSTDIR
    991 	{ LOSTFOUNDINO, sizeof(struct direct), 10, "lost+found" },
    992 #endif
    993 };
    994 #ifdef LOSTDIR
    995 struct direct lost_found_dir[] = {
    996 	{ LOSTFOUNDINO, sizeof(struct direct), DT_DIR, 1, "." },
    997 	{ ROOTINO, sizeof(struct direct), DT_DIR, 2, ".." },
    998 	{ 0, DIRBLKSIZ, 0, 0, 0 },
    999 };
   1000 struct odirect olost_found_dir[] = {
   1001 	{ LOSTFOUNDINO, sizeof(struct direct), 1, "." },
   1002 	{ ROOTINO, sizeof(struct direct), 2, ".." },
   1003 	{ 0, DIRBLKSIZ, 0, 0 },
   1004 };
   1005 #endif
   1006 char buf[MAXBSIZE];
   1007 static void copy_dir(struct direct *, struct direct *);
   1008 
   1009 int
   1010 fsinit(const struct timeval *tv, mode_t mfsmode, uid_t mfsuid, gid_t mfsgid)
   1011 {
   1012 	union dinode node;
   1013 #ifdef LOSTDIR
   1014 	int i;
   1015 	int dirblksiz = DIRBLKSIZ;
   1016 	if (isappleufs)
   1017 		dirblksiz = APPLEUFS_DIRBLKSIZ;
   1018 #endif
   1019 
   1020 	/*
   1021 	 * initialize the node
   1022 	 */
   1023 
   1024 #ifdef LOSTDIR
   1025 	/*
   1026 	 * create the lost+found directory
   1027 	 */
   1028 	memset(&node, 0, sizeof(node));
   1029 	if (Oflag == 0) {
   1030 		(void)makedir((struct direct *)olost_found_dir, 2);
   1031 		for (i = dirblksiz; i < sblock.fs_bsize; i += dirblksiz)
   1032 			copy_dir((struct direct*)&olost_found_dir[2],
   1033 				(struct direct*)&buf[i]);
   1034 	} else {
   1035 		(void)makedir(lost_found_dir, 2);
   1036 		for (i = dirblksiz; i < sblock.fs_bsize; i += dirblksiz)
   1037 			copy_dir(&lost_found_dir[2], (struct direct*)&buf[i]);
   1038 	}
   1039 	if (sblock.fs_magic == FS_UFS1_MAGIC) {
   1040 		node.dp1.di_atime = tv->tv_sec;
   1041 		node.dp1.di_atimensec = tv->tv_usec * 1000;
   1042 		node.dp1.di_mtime = tv->tv_sec;
   1043 		node.dp1.di_mtimensec = tv->tv_usec * 1000;
   1044 		node.dp1.di_ctime = tv->tv_sec;
   1045 		node.dp1.di_ctimensec = tv->tv_usec * 1000;
   1046 		node.dp1.di_mode = IFDIR | UMASK;
   1047 		node.dp1.di_nlink = 2;
   1048 		node.dp1.di_size = sblock.fs_bsize;
   1049 		node.dp1.di_db[0] = alloc(node.dp1.di_size, node.dp1.di_mode);
   1050 		if (node.dp1.di_db[0] == 0)
   1051 			return (0);
   1052 		node.dp1.di_blocks = btodb(fragroundup(&sblock,
   1053 		    node.dp1.di_size));
   1054 		node.dp1.di_uid = geteuid();
   1055 		node.dp1.di_gid = getegid();
   1056 		wtfs(fsbtodb(&sblock, node.dp1.di_db[0]), node.dp1.di_size,
   1057 		    buf);
   1058 	} else {
   1059 		node.dp2.di_atime = tv->tv_sec;
   1060 		node.dp2.di_atimensec = tv->tv_usec * 1000;
   1061 		node.dp2.di_mtime = tv->tv_sec;
   1062 		node.dp2.di_mtimensec = tv->tv_usec * 1000;
   1063 		node.dp2.di_ctime = tv->tv_sec;
   1064 		node.dp2.di_ctimensec = tv->tv_usec * 1000;
   1065 		node.dp2.di_birthtime = tv->tv_sec;
   1066 		node.dp2.di_birthnsec = tv->tv_usec * 1000;
   1067 		node.dp2.di_mode = IFDIR | UMASK;
   1068 		node.dp2.di_nlink = 2;
   1069 		node.dp2.di_size = sblock.fs_bsize;
   1070 		node.dp2.di_db[0] = alloc(node.dp2.di_size, node.dp2.di_mode);
   1071 		if (node.dp2.di_db[0] == 0)
   1072 			return (0);
   1073 		node.dp2.di_blocks = btodb(fragroundup(&sblock,
   1074 		    node.dp2.di_size));
   1075 		node.dp2.di_uid = geteuid();
   1076 		node.dp2.di_gid = getegid();
   1077 		wtfs(fsbtodb(&sblock, node.dp2.di_db[0]), node.dp2.di_size,
   1078 		    buf);
   1079 	}
   1080 	iput(&node, LOSTFOUNDINO);
   1081 #endif
   1082 	/*
   1083 	 * create the root directory
   1084 	 */
   1085 	memset(&node, 0, sizeof(node));
   1086 	if (Oflag <= 1) {
   1087 		if (mfs) {
   1088 			node.dp1.di_mode = IFDIR | mfsmode;
   1089 			node.dp1.di_uid = mfsuid;
   1090 			node.dp1.di_gid = mfsgid;
   1091 		} else {
   1092 			node.dp1.di_mode = IFDIR | UMASK;
   1093 			node.dp1.di_uid = geteuid();
   1094 			node.dp1.di_gid = getegid();
   1095 		}
   1096 		node.dp1.di_nlink = PREDEFDIR;
   1097 		if (Oflag == 0)
   1098 			node.dp1.di_size = makedir((struct direct *)oroot_dir,
   1099 			    PREDEFDIR);
   1100 		else
   1101 			node.dp1.di_size = makedir(root_dir, PREDEFDIR);
   1102 		node.dp1.di_db[0] = alloc(sblock.fs_fsize, node.dp1.di_mode);
   1103 		if (node.dp1.di_db[0] == 0)
   1104 			return (0);
   1105 		node.dp1.di_blocks = btodb(fragroundup(&sblock,
   1106 		    node.dp1.di_size));
   1107 		wtfs(fsbtodb(&sblock, node.dp1.di_db[0]), sblock.fs_fsize, buf);
   1108 	} else {
   1109 		if (mfs) {
   1110 			node.dp2.di_mode = IFDIR | mfsmode;
   1111 			node.dp2.di_uid = mfsuid;
   1112 			node.dp2.di_gid = mfsgid;
   1113 		} else {
   1114 			node.dp2.di_mode = IFDIR | UMASK;
   1115 			node.dp2.di_uid = geteuid();
   1116 			node.dp2.di_gid = getegid();
   1117 		}
   1118 		node.dp2.di_atime = tv->tv_sec;
   1119 		node.dp2.di_atimensec = tv->tv_usec * 1000;
   1120 		node.dp2.di_mtime = tv->tv_sec;
   1121 		node.dp2.di_mtimensec = tv->tv_usec * 1000;
   1122 		node.dp2.di_ctime = tv->tv_sec;
   1123 		node.dp2.di_ctimensec = tv->tv_usec * 1000;
   1124 		node.dp2.di_birthtime = tv->tv_sec;
   1125 		node.dp2.di_birthnsec = tv->tv_usec * 1000;
   1126 		node.dp2.di_nlink = PREDEFDIR;
   1127 		node.dp2.di_size = makedir(root_dir, PREDEFDIR);
   1128 		node.dp2.di_db[0] = alloc(sblock.fs_fsize, node.dp2.di_mode);
   1129 		if (node.dp2.di_db[0] == 0)
   1130 			return (0);
   1131 		node.dp2.di_blocks = btodb(fragroundup(&sblock,
   1132 		    node.dp2.di_size));
   1133 		wtfs(fsbtodb(&sblock, node.dp2.di_db[0]), sblock.fs_fsize, buf);
   1134 	}
   1135 	iput(&node, ROOTINO);
   1136 	return (1);
   1137 }
   1138 
   1139 /*
   1140  * construct a set of directory entries in "buf".
   1141  * return size of directory.
   1142  */
   1143 int
   1144 makedir(struct direct *protodir, int entries)
   1145 {
   1146 	char *cp;
   1147 	int i, spcleft;
   1148 	int dirblksiz = DIRBLKSIZ;
   1149 	if (isappleufs)
   1150 		dirblksiz = APPLEUFS_DIRBLKSIZ;
   1151 
   1152 	memset(buf, 0, DIRBLKSIZ);
   1153 	spcleft = dirblksiz;
   1154 	for (cp = buf, i = 0; i < entries - 1; i++) {
   1155 		protodir[i].d_reclen = DIRSIZ(Oflag == 0, &protodir[i], 0);
   1156 		copy_dir(&protodir[i], (struct direct*)cp);
   1157 		cp += protodir[i].d_reclen;
   1158 		spcleft -= protodir[i].d_reclen;
   1159 	}
   1160 	protodir[i].d_reclen = spcleft;
   1161 	copy_dir(&protodir[i], (struct direct*)cp);
   1162 	return (dirblksiz);
   1163 }
   1164 
   1165 /*
   1166  * allocate a block or frag
   1167  */
   1168 daddr_t
   1169 alloc(int size, int mode)
   1170 {
   1171 	int i, frag;
   1172 	daddr_t d, blkno;
   1173 
   1174 	rdfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize, &acg);
   1175 	/* fs -> host byte order */
   1176 	if (needswap)
   1177 		ffs_cg_swap(&acg, &acg, &sblock);
   1178 	if (acg.cg_magic != CG_MAGIC) {
   1179 		printf("cg 0: bad magic number\n");
   1180 		return (0);
   1181 	}
   1182 	if (acg.cg_cs.cs_nbfree == 0) {
   1183 		printf("first cylinder group ran out of space\n");
   1184 		return (0);
   1185 	}
   1186 	for (d = 0; d < acg.cg_ndblk; d += sblock.fs_frag)
   1187 		if (isblock(&sblock, cg_blksfree(&acg, 0),
   1188 		    d >> sblock.fs_fragshift))
   1189 			goto goth;
   1190 	printf("internal error: can't find block in cyl 0\n");
   1191 	return (0);
   1192 goth:
   1193 	blkno = fragstoblks(&sblock, d);
   1194 	clrblock(&sblock, cg_blksfree(&acg, 0), blkno);
   1195 	if (sblock.fs_contigsumsize > 0)
   1196 		clrbit(cg_clustersfree(&acg, 0), blkno);
   1197 	acg.cg_cs.cs_nbfree--;
   1198 	sblock.fs_cstotal.cs_nbfree--;
   1199 	fscs_0->cs_nbfree--;
   1200 	if (mode & IFDIR) {
   1201 		acg.cg_cs.cs_ndir++;
   1202 		sblock.fs_cstotal.cs_ndir++;
   1203 		fscs_0->cs_ndir++;
   1204 	}
   1205 	if (Oflag <= 1) {
   1206 		int cn = old_cbtocylno(&sblock, d);
   1207 		old_cg_blktot(&acg, 0)[cn]--;
   1208 		old_cg_blks(&sblock, &acg,
   1209 		    cn, 0)[old_cbtorpos(&sblock, d)]--;
   1210 	}
   1211 	if (size != sblock.fs_bsize) {
   1212 		frag = howmany(size, sblock.fs_fsize);
   1213 		fscs_0->cs_nffree += sblock.fs_frag - frag;
   1214 		sblock.fs_cstotal.cs_nffree += sblock.fs_frag - frag;
   1215 		acg.cg_cs.cs_nffree += sblock.fs_frag - frag;
   1216 		acg.cg_frsum[sblock.fs_frag - frag]++;
   1217 		for (i = frag; i < sblock.fs_frag; i++)
   1218 			setbit(cg_blksfree(&acg, 0), d + i);
   1219 	}
   1220 	/* host -> fs byte order */
   1221 	if (needswap)
   1222 		ffs_cg_swap(&acg, &acg, &sblock);
   1223 	wtfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize, &acg);
   1224 	return (d);
   1225 }
   1226 
   1227 /*
   1228  * Allocate an inode on the disk
   1229  */
   1230 static void
   1231 iput(union dinode *ip, ino_t ino)
   1232 {
   1233 	daddr_t d;
   1234 	int c, i;
   1235 	struct ufs1_dinode *dp1;
   1236 	struct ufs2_dinode *dp2;
   1237 
   1238 	c = ino_to_cg(&sblock, ino);
   1239 	rdfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize, &acg);
   1240 	/* fs -> host byte order */
   1241 	if (needswap)
   1242 		ffs_cg_swap(&acg, &acg, &sblock);
   1243 	if (acg.cg_magic != CG_MAGIC) {
   1244 		printf("cg 0: bad magic number\n");
   1245 		exit(31);
   1246 	}
   1247 	acg.cg_cs.cs_nifree--;
   1248 	setbit(cg_inosused(&acg, 0), ino);
   1249 	/* host -> fs byte order */
   1250 	if (needswap)
   1251 		ffs_cg_swap(&acg, &acg, &sblock);
   1252 	wtfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize, &acg);
   1253 	sblock.fs_cstotal.cs_nifree--;
   1254 	fscs_0->cs_nifree--;
   1255 	if (ino >= sblock.fs_ipg * sblock.fs_ncg) {
   1256 		printf("fsinit: inode value out of range (%llu).\n",
   1257 		    (unsigned long long)ino);
   1258 		exit(32);
   1259 	}
   1260 	d = fsbtodb(&sblock, ino_to_fsba(&sblock, ino));
   1261 	rdfs(d, sblock.fs_bsize, (char *)iobuf);
   1262 	if (sblock.fs_magic == FS_UFS1_MAGIC) {
   1263 		dp1 = (struct ufs1_dinode *)iobuf;
   1264 		dp1 += ino_to_fsbo(&sblock, ino);
   1265 		if (needswap) {
   1266 			ffs_dinode1_swap(&ip->dp1, dp1);
   1267 			/* ffs_dinode1_swap() doesn't swap blocks addrs */
   1268 			for (i=0; i<NDADDR + NIADDR; i++)
   1269 			    dp1->di_db[i] = bswap32(ip->dp1.di_db[i]);
   1270 		} else
   1271 			*dp1 = ip->dp1;
   1272 		dp1->di_gen = arc4random() & INT32_MAX;
   1273 	} else {
   1274 		dp2 = (struct ufs2_dinode *)iobuf;
   1275 		dp2 += ino_to_fsbo(&sblock, ino);
   1276 		if (needswap) {
   1277 			ffs_dinode2_swap(&ip->dp2, dp2);
   1278 			for (i=0; i<NDADDR + NIADDR; i++)
   1279 			    dp2->di_db[i] = bswap64(ip->dp2.di_db[i]);
   1280 		} else
   1281 			*dp2 = ip->dp2;
   1282 		dp2->di_gen = arc4random() & INT32_MAX;
   1283 	}
   1284 	wtfs(d, sblock.fs_bsize, iobuf);
   1285 }
   1286 
   1287 /*
   1288  * read a block from the file system
   1289  */
   1290 void
   1291 rdfs(daddr_t bno, int size, void *bf)
   1292 {
   1293 	int n;
   1294 	off_t offset;
   1295 
   1296 #ifdef MFS
   1297 	if (mfs) {
   1298 		if (Nflag)
   1299 			memset(bf, 0, size);
   1300 		else
   1301 			memmove(bf, membase + bno * sectorsize, size);
   1302 		return;
   1303 	}
   1304 #endif
   1305 	offset = bno;
   1306 	n = pread(fsi, bf, size, offset * sectorsize);
   1307 	if (n != size) {
   1308 		printf("rdfs: read error for sector %lld: %s\n",
   1309 		    (long long)bno, strerror(errno));
   1310 		exit(34);
   1311 	}
   1312 }
   1313 
   1314 /*
   1315  * write a block to the file system
   1316  */
   1317 void
   1318 wtfs(daddr_t bno, int size, void *bf)
   1319 {
   1320 	int n;
   1321 	off_t offset;
   1322 
   1323 	if (Nflag)
   1324 		return;
   1325 #ifdef MFS
   1326 	if (mfs) {
   1327 		memmove(membase + bno * sectorsize, bf, size);
   1328 		return;
   1329 	}
   1330 #endif
   1331 	offset = bno;
   1332 	n = pwrite(fso, bf, size, offset * sectorsize);
   1333 	if (n != size) {
   1334 		printf("wtfs: write error for sector %lld: %s\n",
   1335 		    (long long)bno, strerror(errno));
   1336 		exit(36);
   1337 	}
   1338 }
   1339 
   1340 /*
   1341  * check if a block is available
   1342  */
   1343 int
   1344 isblock(struct fs *fs, unsigned char *cp, int h)
   1345 {
   1346 	unsigned char mask;
   1347 
   1348 	switch (fs->fs_fragshift) {
   1349 	case 3:
   1350 		return (cp[h] == 0xff);
   1351 	case 2:
   1352 		mask = 0x0f << ((h & 0x1) << 2);
   1353 		return ((cp[h >> 1] & mask) == mask);
   1354 	case 1:
   1355 		mask = 0x03 << ((h & 0x3) << 1);
   1356 		return ((cp[h >> 2] & mask) == mask);
   1357 	case 0:
   1358 		mask = 0x01 << (h & 0x7);
   1359 		return ((cp[h >> 3] & mask) == mask);
   1360 	default:
   1361 #ifdef STANDALONE
   1362 		printf("isblock bad fs_fragshift %d\n", fs->fs_fragshift);
   1363 #else
   1364 		fprintf(stderr, "isblock bad fs_fragshift %d\n",
   1365 		    fs->fs_fragshift);
   1366 #endif
   1367 		return (0);
   1368 	}
   1369 }
   1370 
   1371 /*
   1372  * take a block out of the map
   1373  */
   1374 void
   1375 clrblock(struct fs *fs, unsigned char *cp, int h)
   1376 {
   1377 	switch ((fs)->fs_fragshift) {
   1378 	case 3:
   1379 		cp[h] = 0;
   1380 		return;
   1381 	case 2:
   1382 		cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2));
   1383 		return;
   1384 	case 1:
   1385 		cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1));
   1386 		return;
   1387 	case 0:
   1388 		cp[h >> 3] &= ~(0x01 << (h & 0x7));
   1389 		return;
   1390 	default:
   1391 #ifdef STANDALONE
   1392 		printf("clrblock bad fs_fragshift %d\n", fs->fs_fragshift);
   1393 #else
   1394 		fprintf(stderr, "clrblock bad fs_fragshift %d\n",
   1395 		    fs->fs_fragshift);
   1396 #endif
   1397 		return;
   1398 	}
   1399 }
   1400 
   1401 /*
   1402  * put a block into the map
   1403  */
   1404 void
   1405 setblock(struct fs *fs, unsigned char *cp, int h)
   1406 {
   1407 	switch (fs->fs_fragshift) {
   1408 	case 3:
   1409 		cp[h] = 0xff;
   1410 		return;
   1411 	case 2:
   1412 		cp[h >> 1] |= (0x0f << ((h & 0x1) << 2));
   1413 		return;
   1414 	case 1:
   1415 		cp[h >> 2] |= (0x03 << ((h & 0x3) << 1));
   1416 		return;
   1417 	case 0:
   1418 		cp[h >> 3] |= (0x01 << (h & 0x7));
   1419 		return;
   1420 	default:
   1421 #ifdef STANDALONE
   1422 		printf("setblock bad fs_frag %d\n", fs->fs_fragshift);
   1423 #else
   1424 		fprintf(stderr, "setblock bad fs_fragshift %d\n",
   1425 		    fs->fs_fragshift);
   1426 #endif
   1427 		return;
   1428 	}
   1429 }
   1430 
   1431 /* copy a direntry to a buffer, in fs byte order */
   1432 static void
   1433 copy_dir(struct direct *dir, struct direct *dbuf)
   1434 {
   1435 	memcpy(dbuf, dir, DIRSIZ(Oflag == 0, dir, 0));
   1436 	if (needswap) {
   1437 		dbuf->d_ino = bswap32(dir->d_ino);
   1438 		dbuf->d_reclen = bswap16(dir->d_reclen);
   1439 		if (Oflag == 0)
   1440 			((struct odirect*)dbuf)->d_namlen =
   1441 				bswap16(((struct odirect*)dir)->d_namlen);
   1442 	}
   1443 }
   1444 
   1445 static int
   1446 ilog2(int val)
   1447 {
   1448 	u_int n;
   1449 
   1450 	for (n = 0; n < sizeof(n) * CHAR_BIT; n++)
   1451 		if (1 << n == val)
   1452 			return (n);
   1453 	errx(1, "ilog2: %d is not a power of 2\n", val);
   1454 }
   1455 
   1456 static void
   1457 zap_old_sblock(int sblkoff)
   1458 {
   1459 	static int cg0_data;
   1460 	uint32_t oldfs[SBLOCKSIZE / 4];
   1461 	static const struct fsm {
   1462 		uint32_t	offset;
   1463 		uint32_t	magic;
   1464 		uint32_t	mask;
   1465 	} fs_magics[] = {
   1466 		{offsetof(struct fs, fs_magic)/4, FS_UFS1_MAGIC, ~0u},
   1467 		{offsetof(struct fs, fs_magic)/4, FS_UFS2_MAGIC, ~0u},
   1468 		{0, 0x70162, ~0u},		/* LFS_MAGIC */
   1469 		{14, 0xef53, 0xffff},		/* EXT2FS (little) */
   1470 		{14, 0xef530000, 0xffff0000},	/* EXT2FS (big) */
   1471 		{~0u},
   1472 	};
   1473 	const struct fsm *fsm;
   1474 
   1475 	if (Nflag)
   1476 		return;
   1477 
   1478 	if (sblkoff == 0)	/* Why did UFS2 add support for this?  sigh. */
   1479 		return;
   1480 
   1481 	if (cg0_data == 0)
   1482 		/* For FFSv1 this could include all the inodes. */
   1483 		cg0_data = cgsblock(&sblock, 0) * sblock.fs_fsize + iobufsize;
   1484 
   1485 	/* Ignore anything that is beyond our filesystem */
   1486 	if ((sblkoff + SBLOCKSIZE)/sectorsize >= fssize)
   1487 		return;
   1488 	/* Zero anything inside our filesystem... */
   1489 	if (sblkoff >= sblock.fs_sblockloc) {
   1490 		/* ...unless we will write that area anyway */
   1491 		if (sblkoff >= cg0_data)
   1492 			wtfs(sblkoff / sectorsize,
   1493 			    roundup(sizeof sblock, sectorsize), iobuf);
   1494 		return;
   1495 	}
   1496 
   1497 	/* The sector might contain boot code, so we must validate it */
   1498 	rdfs(sblkoff/sectorsize, sizeof oldfs, &oldfs);
   1499 	for (fsm = fs_magics; ; fsm++) {
   1500 		uint32_t v;
   1501 		if (fsm->mask == 0)
   1502 			return;
   1503 		v = oldfs[fsm->offset];
   1504 		if ((v & fsm->mask) == fsm->magic ||
   1505 		    (bswap32(v) & fsm->mask) == fsm->magic)
   1506 			break;
   1507 	}
   1508 
   1509 	/* Just zap the magic number */
   1510 	oldfs[fsm->offset] = 0;
   1511 	wtfs(sblkoff/sectorsize, sizeof oldfs, &oldfs);
   1512 }
   1513 
   1514 
   1515 #ifdef MFS
   1516 /*
   1517  * XXX!
   1518  * Attempt to guess how much more space is available for process data.  The
   1519  * heuristic we use is
   1520  *
   1521  *	max_data_limit - (sbrk(0) - etext) - 128kB
   1522  *
   1523  * etext approximates that start address of the data segment, and the 128kB
   1524  * allows some slop for both segment gap between text and data, and for other
   1525  * (libc) malloc usage.
   1526  */
   1527 static void
   1528 calc_memfree(void)
   1529 {
   1530 	extern char etext;
   1531 	struct rlimit rlp;
   1532 	u_long base;
   1533 
   1534 	base = (u_long)sbrk(0) - (u_long)&etext;
   1535 	if (getrlimit(RLIMIT_DATA, &rlp) < 0)
   1536 		perror("getrlimit");
   1537 	rlp.rlim_cur = rlp.rlim_max;
   1538 	if (setrlimit(RLIMIT_DATA, &rlp) < 0)
   1539 		perror("setrlimit");
   1540 	memleft = rlp.rlim_max - base - (128 * 1024);
   1541 }
   1542 
   1543 /*
   1544  * Internal version of malloc that trims the requested size if not enough
   1545  * memory is available.
   1546  */
   1547 static void *
   1548 mkfs_malloc(size_t size)
   1549 {
   1550 	u_long pgsz;
   1551 
   1552 	if (size == 0)
   1553 		return (NULL);
   1554 	if (memleft == 0)
   1555 		calc_memfree();
   1556 
   1557 	pgsz = getpagesize() - 1;
   1558 	size = (size + pgsz) &~ pgsz;
   1559 	if (size > memleft)
   1560 		size = memleft;
   1561 	memleft -= size;
   1562 	return (mmap(0, size, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE,
   1563 	    -1, 0));
   1564 }
   1565 #endif	/* MFS */
   1566