bridge(4): document net.link.bridge.pfil_onlyip

[dragonfly.git] / sbin / newfs / mkfs.c

/*
 * Copyright (c) 1980, 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * @(#)mkfs.c   8.11 (Berkeley) 5/3/95
 * $FreeBSD: src/sbin/newfs/mkfs.c,v 1.29.2.6 2001/09/21 19:15:21 dillon Exp $
 */

#include "defs.h"

#include <inttypes.h>
#include <stdlib.h>

#include <bus/cam/scsi/scsi_daio.h>

/*
 * make file system for cylinder-group style file systems
 */

/*
 * We limit the size of the inode map to be no more than a
 * third of the cylinder group space, since we must leave at
 * least an equal amount of space for the block map.
 *
 * N.B.: MAXIPG must be a multiple of INOPB(fs).
 */
#define MAXIPG(fs)      roundup((fs)->fs_bsize * NBBY / 3, INOPB(fs))

#define UMASK           0755
#define MAXINOPB        (MAXBSIZE / sizeof(struct ufs1_dinode))

#ifdef STANDALONE
#error "mkfs.c: STANDALONE compilation no longer supported"
#endif

/*
 * variables set up by front end.
 */
extern int      mfs;            /* run as the memory based filesystem */
extern char     *mfs_mtpt;      /* mount point for mfs          */ 
extern struct stat mfs_mtstat;  /* stat prior to mount          */
extern int      Lflag;          /* add a volume label */
extern int      Nflag;          /* run mkfs without writing file system */
extern int      Oflag;          /* format as an 4.3BSD file system */
extern int      Uflag;          /* enable soft updates for file system */
extern int      Eflag;          /* erase contents using TRIM */
extern uint64_t slice_offset;   /* Pysical device slice offset */
extern u_long   fssize;         /* file system size */
extern int      ntracks;        /* # tracks/cylinder */
extern int      nsectors;       /* # sectors/track */
extern int      nphyssectors;   /* # sectors/track including spares */
extern int      secpercyl;      /* sectors per cylinder */
extern int      sectorsize;     /* bytes/sector */
extern int      realsectorsize; /* bytes/sector in hardware*/
extern int      rpm;            /* revolutions/minute of drive */
extern int      interleave;     /* hardware sector interleave */
extern int      trackskew;      /* sector 0 skew, per track */
extern int      fsize;          /* fragment size */
extern int      bsize;          /* block size */
extern int      cpg;            /* cylinders/cylinder group */
extern int      cpgflg;         /* cylinders/cylinder group flag was given */
extern int      minfree;        /* free space threshold */
extern int      opt;            /* optimization preference (space or time) */
extern int      density;        /* number of bytes per inode */
extern int      maxcontig;      /* max contiguous blocks to allocate */
extern int      rotdelay;       /* rotational delay between blocks */
extern int      maxbpg;         /* maximum blocks per file in a cyl group */
extern int      nrpos;          /* # of distinguished rotational positions */
extern int      bbsize;         /* boot block size */
extern int      sbsize;         /* superblock size */
extern int      avgfilesize;    /* expected average file size */
extern int      avgfilesperdir; /* expected number of files per directory */
extern caddr_t  membase;        /* start address of memory based filesystem */
extern char *   filename;
extern u_char   *volumelabel;   /* volume label for filesystem */
extern struct disktab geom;

extern void fatal(const char *fmt, ...);

union {
        struct fs fs;
        char pad[SBSIZE];
} fsun;
#define sblock  fsun.fs
struct  csum *fscs;

union {
        struct cg cg;
        char pad[MAXBSIZE];
} cgun;
#define acg     cgun.cg

struct ufs1_dinode zino[MAXBSIZE / sizeof(struct ufs1_dinode)];

int     fsi, fso;
static fsnode_t copyroot;
static fsnode_t copyhlinks;
#ifdef FSIRAND
int     randinit;
#endif
daddr_t alloc(int, int);
long    calcipg(long, long, off_t *);
static int charsperline(void);
void clrblock(struct fs *, unsigned char *, int);
void fsinit(time_t);
void initcg(int, time_t);
int isblock(struct fs *, unsigned char *, int);
void iput(struct ufs1_dinode *, ino_t);
int makedir(struct direct *, int);
void parentready(int);
void rdfs(daddr_t, int, char *);
void setblock(struct fs *, unsigned char *, int);
void started(int) __dead2;
void erfs(off_t, off_t);
void wtfs(daddr_t, int, char *);
void wtfsflush(void);

int mfs_ppid = 0;
int parentready_signalled;

void
mkfs(char *fsys, int fi, int fo, const char *mfscopy)
{
        long i, mincpc, mincpg, inospercg;
        long cylno, rpos, blk, j, emitwarn = 0;
        long used, mincpgcnt, bpcg;
        off_t usedb;
        long mapcramped, inodecramped;
        long postblsize, rotblsize, totalsbsize;
        int status, fd;
        time_t utime;
        quad_t sizepb;
        int width;
        char tmpbuf[100];       /* XXX this will break in about 2,500 years */

        time(&utime);
#ifdef FSIRAND
        if (!randinit) {
                randinit = 1;
                srandomdev();
        }
#endif
        if (mfs) {
                int omask;
                pid_t child;

                mfs_ppid = getpid();
                signal(SIGUSR1, parentready);
                if ((child = fork()) != 0) {
                        /*
                         * Parent
                         */
                        if (child == -1)
                                err(10, "mfs");
                        if (mfscopy)
                            copyroot = FSCopy(&copyhlinks, mfscopy);
                        signal(SIGUSR1, started);
                        kill(child, SIGUSR1);
                        while (waitpid(child, &status, 0) != child)
                                ;
                        exit(WEXITSTATUS(status));
                        /* NOTREACHED */
                }

                /*
                 * Child
                 */
                omask = sigblock(sigmask(SIGUSR1));
                while (parentready_signalled == 0)
                        sigpause(omask);
                sigsetmask(omask);
                if (filename != NULL) {
                        unsigned char buf[BUFSIZ];
                        unsigned long l, l1;
                        ssize_t w;

                        fd = open(filename, O_RDWR|O_TRUNC|O_CREAT, 0644);
                        if(fd < 0)
                                err(12, "%s", filename);
                        l1 = fssize * sectorsize;
                        if (l1 > BUFSIZ)
                                l1 = BUFSIZ;
                        for (l = 0; l < fssize * (u_long)sectorsize; l += l1) {
                                w = write(fd, buf, l1);
                                if (w < 0 || (u_long)w != l1)
                                        err(12, "%s", filename);
                        }
                        membase = mmap(NULL, fssize * sectorsize,
                                       PROT_READ|PROT_WRITE,
                                       MAP_SHARED, fd, 0);
                        if (membase == MAP_FAILED)
                                err(12, "mmap");
                        close(fd);
                } else {
                        membase = mmap(NULL, fssize * sectorsize,
                                       PROT_READ|PROT_WRITE,
                                       MAP_SHARED|MAP_ANON, -1, 0);
                        if (membase == MAP_FAILED)
                                errx(13, "mmap (anonymous memory) failed");
                }
        }
        fsi = fi;
        fso = fo;
        if (Oflag) {
                sblock.fs_inodefmt = FS_42INODEFMT;
                sblock.fs_maxsymlinklen = 0;
        } else {
                sblock.fs_inodefmt = FS_44INODEFMT;
                sblock.fs_maxsymlinklen = UFS1_MAXSYMLINKLEN;
        }
        if (Uflag)
                sblock.fs_flags |= FS_DOSOFTDEP;
        if (Lflag)
                strlcpy(sblock.fs_volname, volumelabel, MAXVOLLEN);

        /*
         * Validate the given file system size.
         * Verify that its last block can actually be accessed.
         */
        if (fssize == 0)
                printf("preposterous size %lu\n", fssize), exit(13);
        wtfs(fssize - (realsectorsize / DEV_BSIZE), realsectorsize,
                 (char *)&sblock);
        /*
         * collect and verify the sector and track info
         */
        sblock.fs_nsect = nsectors;
        sblock.fs_ntrak = ntracks;
        if (sblock.fs_ntrak <= 0)
                printf("preposterous ntrak %d\n", sblock.fs_ntrak), exit(14);
        if (sblock.fs_nsect <= 0)
                printf("preposterous nsect %d\n", sblock.fs_nsect), exit(15);
        /*
         * collect and verify the filesystem density info
         */
        sblock.fs_avgfilesize = avgfilesize;
        sblock.fs_avgfpdir = avgfilesperdir;
        if (sblock.fs_avgfilesize <= 0)
                printf("illegal expected average file size %d\n",
                    sblock.fs_avgfilesize), exit(14);
        if (sblock.fs_avgfpdir <= 0)
                printf("illegal expected number of files per directory %d\n",
                    sblock.fs_avgfpdir), exit(15);
        /*
         * collect and verify the block and fragment sizes
         */
        sblock.fs_bsize = bsize;
        sblock.fs_fsize = fsize;
        if (!powerof2(sblock.fs_bsize)) {
                printf("block size must be a power of 2, not %d\n",
                    sblock.fs_bsize);
                exit(16);
        }
        if (!powerof2(sblock.fs_fsize)) {
                printf("fragment size must be a power of 2, not %d\n",
                    sblock.fs_fsize);
                exit(17);
        }
        if (sblock.fs_fsize < sectorsize) {
                printf("fragment size %d is too small, minimum is %d\n",
                    sblock.fs_fsize, sectorsize);
                exit(18);
        }
        if (sblock.fs_bsize < MINBSIZE) {
                printf("block size %d is too small, minimum is %d\n",
                    sblock.fs_bsize, MINBSIZE);
                exit(19);
        }
        if (sblock.fs_bsize < sblock.fs_fsize) {
                printf("block size (%d) cannot be smaller than fragment size (%d)\n",
                    sblock.fs_bsize, sblock.fs_fsize);
                exit(20);
        }
        sblock.fs_bmask = ~(sblock.fs_bsize - 1);
        sblock.fs_fmask = ~(sblock.fs_fsize - 1);
        sblock.fs_qbmask = ~sblock.fs_bmask;
        sblock.fs_qfmask = ~sblock.fs_fmask;
        for (sblock.fs_bshift = 0, i = sblock.fs_bsize; i > 1; i >>= 1)
                sblock.fs_bshift++;
        for (sblock.fs_fshift = 0, i = sblock.fs_fsize; i > 1; i >>= 1)
                sblock.fs_fshift++;
        sblock.fs_frag = numfrags(&sblock, sblock.fs_bsize);
        for (sblock.fs_fragshift = 0, i = sblock.fs_frag; i > 1; i >>= 1)
                sblock.fs_fragshift++;
        if (sblock.fs_frag > MAXFRAG) {
                printf("fragment size %d is too small, minimum with block size %d is %d\n",
                    sblock.fs_fsize, sblock.fs_bsize,
                    sblock.fs_bsize / MAXFRAG);
                exit(21);
        }
        sblock.fs_nrpos = nrpos;
        sblock.fs_nindir = sblock.fs_bsize / sizeof(daddr_t);
        sblock.fs_inopb = sblock.fs_bsize / sizeof(struct ufs1_dinode);
        sblock.fs_nspf = sblock.fs_fsize / sectorsize;
        for (sblock.fs_fsbtodb = 0, i = NSPF(&sblock); i > 1; i >>= 1)
                sblock.fs_fsbtodb++;
        sblock.fs_sblkno =
            roundup(howmany(bbsize + sbsize, sblock.fs_fsize), sblock.fs_frag);
        sblock.fs_cblkno = (daddr_t)(sblock.fs_sblkno +
            roundup(howmany(sbsize, sblock.fs_fsize), sblock.fs_frag));
        sblock.fs_iblkno = sblock.fs_cblkno + sblock.fs_frag;
        sblock.fs_cgoffset = roundup(
            howmany(sblock.fs_nsect, NSPF(&sblock)), sblock.fs_frag);
        for (sblock.fs_cgmask = 0xffffffff, i = sblock.fs_ntrak; i > 1; i >>= 1)
                sblock.fs_cgmask <<= 1;
        if (!powerof2(sblock.fs_ntrak))
                sblock.fs_cgmask <<= 1;
        sblock.fs_maxfilesize = sblock.fs_bsize * UFS_NDADDR - 1;
        for (sizepb = sblock.fs_bsize, i = 0; i < UFS_NIADDR; i++) {
                sizepb *= NINDIR(&sblock);
                sblock.fs_maxfilesize += sizepb;
        }
        /*
         * Validate specified/determined secpercyl
         * and calculate minimum cylinders per group.
         */
        sblock.fs_spc = secpercyl;
        for (sblock.fs_cpc = NSPB(&sblock), i = sblock.fs_spc;
             sblock.fs_cpc > 1 && (i & 1) == 0;
             sblock.fs_cpc >>= 1, i >>= 1)
                /* void */;
        mincpc = sblock.fs_cpc;
        bpcg = sblock.fs_spc * sectorsize;
        inospercg = roundup(bpcg / sizeof(struct ufs1_dinode), INOPB(&sblock));
        if (inospercg > MAXIPG(&sblock))
                inospercg = MAXIPG(&sblock);
        used = (sblock.fs_iblkno + inospercg / INOPF(&sblock)) * NSPF(&sblock);
        mincpgcnt = howmany(sblock.fs_cgoffset * (~sblock.fs_cgmask) + used,
            sblock.fs_spc);
        mincpg = roundup(mincpgcnt, mincpc);
        /*
         * Ensure that cylinder group with mincpg has enough space
         * for block maps.
         */
        sblock.fs_cpg = mincpg;
        sblock.fs_ipg = inospercg;
        if (maxcontig > 1)
                sblock.fs_contigsumsize = MIN(maxcontig, FS_MAXCONTIG);
        mapcramped = 0;
        while (CGSIZE(&sblock) > (uint32_t)sblock.fs_bsize) {
                mapcramped = 1;
                if (sblock.fs_bsize < MAXBSIZE) {
                        sblock.fs_bsize <<= 1;
                        if ((i & 1) == 0) {
                                i >>= 1;
                        } else {
                                sblock.fs_cpc <<= 1;
                                mincpc <<= 1;
                                mincpg = roundup(mincpgcnt, mincpc);
                                sblock.fs_cpg = mincpg;
                        }
                        sblock.fs_frag <<= 1;
                        sblock.fs_fragshift += 1;
                        if (sblock.fs_frag <= MAXFRAG)
                                continue;
                }
                if (sblock.fs_fsize == sblock.fs_bsize) {
                        printf("There is no block size that");
                        printf(" can support this disk\n");
                        exit(22);
                }
                sblock.fs_frag >>= 1;
                sblock.fs_fragshift -= 1;
                sblock.fs_fsize <<= 1;
                sblock.fs_nspf <<= 1;
        }
        /*
         * Ensure that cylinder group with mincpg has enough space for inodes.
         */
        inodecramped = 0;
        inospercg = calcipg(mincpg, bpcg, &usedb);
        sblock.fs_ipg = inospercg;
        while (inospercg > MAXIPG(&sblock)) {
                inodecramped = 1;
                if (mincpc == 1 || sblock.fs_frag == 1 ||
                    sblock.fs_bsize == MINBSIZE)
                        break;
                printf("With a block size of %d %s %d\n", sblock.fs_bsize,
                       "minimum bytes per inode is",
                       (int)((mincpg * (off_t)bpcg - usedb)
                             / MAXIPG(&sblock) + 1));
                sblock.fs_bsize >>= 1;
                sblock.fs_frag >>= 1;
                sblock.fs_fragshift -= 1;
                mincpc >>= 1;
                sblock.fs_cpg = roundup(mincpgcnt, mincpc);
                if (CGSIZE(&sblock) > (uint32_t)sblock.fs_bsize) {
                        sblock.fs_bsize <<= 1;
                        break;
                }
                mincpg = sblock.fs_cpg;
                inospercg = calcipg(mincpg, bpcg, &usedb);
                sblock.fs_ipg = inospercg;
        }
        if (inodecramped) {
                if (inospercg > MAXIPG(&sblock)) {
                        printf("Minimum bytes per inode is %d\n",
                               (int)((mincpg * (off_t)bpcg - usedb)
                                     / MAXIPG(&sblock) + 1));
                } else if (!mapcramped) {
                        printf("With %d bytes per inode, ", density);
                        printf("minimum cylinders per group is %ld\n", mincpg);
                }
        }
        if (mapcramped) {
                printf("With %d sectors per cylinder, ", sblock.fs_spc);
                printf("minimum cylinders per group is %ld\n", mincpg);
        }
        if (inodecramped || mapcramped) {
                if (sblock.fs_bsize != bsize)
                        printf("%s to be changed from %d to %d\n",
                            "This requires the block size",
                            bsize, sblock.fs_bsize);
                if (sblock.fs_fsize != fsize)
                        printf("\t%s to be changed from %d to %d\n",
                            "and the fragment size",
                            fsize, sblock.fs_fsize);
                exit(23);
        }
        /*
         * Calculate the number of cylinders per group
         */
        sblock.fs_cpg = cpg;
        if (sblock.fs_cpg % mincpc != 0) {
                printf("%s groups must have a multiple of %ld cylinders\n",
                        cpgflg ? "Cylinder" : "Warning: cylinder", mincpc);
                sblock.fs_cpg = roundup(sblock.fs_cpg, mincpc);
                if (!cpgflg)
                        cpg = sblock.fs_cpg;
        }
        /*
         * Must ensure there is enough space for inodes.
         */
        sblock.fs_ipg = calcipg(sblock.fs_cpg, bpcg, &usedb);
        while (sblock.fs_ipg > MAXIPG(&sblock)) {
                inodecramped = 1;
                sblock.fs_cpg -= mincpc;
                sblock.fs_ipg = calcipg(sblock.fs_cpg, bpcg, &usedb);
        }
        /*
         * Must ensure there is enough space to hold block map.
         */
        while (CGSIZE(&sblock) > (uint32_t)sblock.fs_bsize) {
                mapcramped = 1;
                sblock.fs_cpg -= mincpc;
                sblock.fs_ipg = calcipg(sblock.fs_cpg, bpcg, &usedb);
        }
        sblock.fs_fpg = (sblock.fs_cpg * sblock.fs_spc) / NSPF(&sblock);
        if ((sblock.fs_cpg * sblock.fs_spc) % NSPB(&sblock) != 0) {
                printf("panic (fs_cpg * fs_spc) %% NSPF != 0");
                exit(24);
        }
        if (sblock.fs_cpg < mincpg) {
                printf("cylinder groups must have at least %ld cylinders\n",
                        mincpg);
                exit(25);
        } else if (sblock.fs_cpg != cpg) {
                if (!cpgflg && !mfs)
                        printf("Warning: ");
                else if (!mapcramped && !inodecramped)
                        exit(26);
                if (!mfs) {
                    if (mapcramped && inodecramped)
                        printf("Block size and bytes per inode restrict");
                    else if (mapcramped)
                        printf("Block size restricts");
                    else
                        printf("Bytes per inode restrict");
                    printf(" cylinders per group to %d.\n", sblock.fs_cpg);
                }
                if (cpgflg)
                        exit(27);
        }
        sblock.fs_cgsize = fragroundup(&sblock, CGSIZE(&sblock));
        /*
         * Now have size for file system and nsect and ntrak.
         * Determine number of cylinders and blocks in the file system.
         */
        sblock.fs_size = fssize = dbtofsb(&sblock, fssize);
        sblock.fs_ncyl = fssize * NSPF(&sblock) / sblock.fs_spc;
        if ((long)fssize * NSPF(&sblock) > sblock.fs_ncyl * sblock.fs_spc) {
                sblock.fs_ncyl++;
                emitwarn = 1;
        }
        if (sblock.fs_ncyl < 1) {
                printf("file systems must have at least one cylinder\n");
                exit(28);
        }
        /*
         * Determine feasability/values of rotational layout tables.
         *
         * The size of the rotational layout tables is limited by the
         * size of the superblock, SBSIZE. The amount of space available
         * for tables is calculated as (SBSIZE - sizeof (struct fs)).
         * The size of these tables is inversely proportional to the block
         * size of the file system. The size increases if sectors per track
         * are not powers of two, because more cylinders must be described
         * by the tables before the rotational pattern repeats (fs_cpc).
         */
        sblock.fs_interleave = interleave;
        sblock.fs_trackskew = trackskew;
        sblock.fs_npsect = nphyssectors;
        sblock.fs_postblformat = FS_DYNAMICPOSTBLFMT;
        sblock.fs_sbsize = fragroundup(&sblock, sizeof(struct fs));
        if (sblock.fs_sbsize > SBSIZE)
                sblock.fs_sbsize = SBSIZE;
        if (sblock.fs_ntrak == 1) {
                sblock.fs_cpc = 0;
                goto next;
        }
        postblsize = sblock.fs_nrpos * sblock.fs_cpc * sizeof(int16_t);
        rotblsize = sblock.fs_cpc * sblock.fs_spc / NSPB(&sblock);
        totalsbsize = sizeof(struct fs) + rotblsize;
        if (sblock.fs_nrpos == 8 && sblock.fs_cpc <= 16) {
                /* use old static table space */
                sblock.fs_postbloff = (char *)(&sblock.fs_opostbl[0][0]) -
                    (char *)(&sblock.fs_firstfield);
                sblock.fs_rotbloff = &sblock.fs_space[0] -
                    (u_char *)(&sblock.fs_firstfield);
        } else {
                /* use dynamic table space */
                sblock.fs_postbloff = &sblock.fs_space[0] -
                    (u_char *)(&sblock.fs_firstfield);
                sblock.fs_rotbloff = sblock.fs_postbloff + postblsize;
                totalsbsize += postblsize;
        }
        if (totalsbsize > SBSIZE ||
            sblock.fs_nsect > (1 << NBBY) * NSPB(&sblock)) {
                printf("%s %s %d %s %d.%s",
                    "Warning: insufficient space in super block for\n",
                    "rotational layout tables with nsect", sblock.fs_nsect,
                    "and ntrak", sblock.fs_ntrak,
                    "\nFile system performance may be impaired.\n");
                sblock.fs_cpc = 0;
                goto next;
        }
        sblock.fs_sbsize = fragroundup(&sblock, totalsbsize);
        if (sblock.fs_sbsize > SBSIZE)
                sblock.fs_sbsize = SBSIZE;
        /*
         * calculate the available blocks for each rotational position
         */
        for (cylno = 0; cylno < sblock.fs_cpc; cylno++)
                for (rpos = 0; rpos < sblock.fs_nrpos; rpos++)
                        fs_postbl(&sblock, cylno)[rpos] = -1;
        for (i = (rotblsize - 1) * sblock.fs_frag;
             i >= 0; i -= sblock.fs_frag) {
                cylno = cbtocylno(&sblock, i);
                rpos = cbtorpos(&sblock, i);
                blk = fragstoblks(&sblock, i);
                if (fs_postbl(&sblock, cylno)[rpos] == -1)
                        fs_rotbl(&sblock)[blk] = 0;
                else
                        fs_rotbl(&sblock)[blk] =
                            fs_postbl(&sblock, cylno)[rpos] - blk;
                fs_postbl(&sblock, cylno)[rpos] = blk;
        }
next:
        /*
         * Compute/validate number of cylinder groups.
         */
        sblock.fs_ncg = sblock.fs_ncyl / sblock.fs_cpg;
        if (sblock.fs_ncyl % sblock.fs_cpg)
                sblock.fs_ncg++;
        sblock.fs_dblkno = sblock.fs_iblkno + sblock.fs_ipg / INOPF(&sblock);
        i = MIN(~sblock.fs_cgmask, sblock.fs_ncg - 1);
        if (cgdmin(&sblock, i) - cgbase(&sblock, i) >= sblock.fs_fpg) {
                printf("inode blocks/cyl group (%ld) >= data blocks (%ld)\n",
                    cgdmin(&sblock, i) - cgbase(&sblock, i) / sblock.fs_frag,
                    (long)(sblock.fs_fpg / sblock.fs_frag));
                printf("number of cylinders per cylinder group (%d) %s.\n",
                    sblock.fs_cpg, "must be increased");
                exit(29);
        }
        j = sblock.fs_ncg - 1;
        if ((i = fssize - j * sblock.fs_fpg) < sblock.fs_fpg &&
            cgdmin(&sblock, j) - cgbase(&sblock, j) > i) {
                if (j == 0) {
                        printf("Filesystem must have at least %d sectors\n",
                            NSPF(&sblock) *
                            (cgdmin(&sblock, 0) + 3 * sblock.fs_frag));
                        exit(30);
                }
                printf(
"Warning: inode blocks/cyl group (%ld) >= data blocks (%ld) in last\n",
                    (cgdmin(&sblock, j) - cgbase(&sblock, j)) / sblock.fs_frag,
                    i / sblock.fs_frag);
                printf(
"    cylinder group. This implies %ld sector(s) cannot be allocated.\n",
                    i * NSPF(&sblock));
                sblock.fs_ncg--;
                sblock.fs_ncyl -= sblock.fs_ncyl % sblock.fs_cpg;
                sblock.fs_size = fssize = sblock.fs_ncyl * sblock.fs_spc /
                    NSPF(&sblock);
                emitwarn = 0;
        }
        if (emitwarn && !mfs) {
                printf("Warning: %lu sector(s) in last cylinder unallocated\n",
                    sblock.fs_spc -
                    (fssize * NSPF(&sblock) - (sblock.fs_ncyl - 1)
                    * sblock.fs_spc));
        }
        /*
         * fill in remaining fields of the super block
         */
        sblock.fs_csaddr = cgdmin(&sblock, 0);
        sblock.fs_cssize =
            fragroundup(&sblock, sblock.fs_ncg * sizeof(struct csum));
        /*
         * The superblock fields 'fs_csmask' and 'fs_csshift' are no
         * longer used. However, we still initialise them so that the
         * filesystem remains compatible with old kernels.
         */
        i = sblock.fs_bsize / sizeof(struct csum);
        sblock.fs_csmask = ~(i - 1);
        for (sblock.fs_csshift = 0; i > 1; i >>= 1)
                sblock.fs_csshift++;
        fscs = (struct csum *)calloc(1, sblock.fs_cssize);
        if (fscs == NULL)
                errx(31, "calloc failed");
        sblock.fs_magic = FS_MAGIC;
        sblock.fs_rotdelay = rotdelay;
        sblock.fs_minfree = minfree;
        sblock.fs_maxcontig = maxcontig;
        sblock.fs_maxbpg = maxbpg;
        sblock.fs_rps = rpm / 60;
        sblock.fs_optim = opt;
        sblock.fs_cgrotor = 0;
        sblock.fs_cstotal.cs_ndir = 0;
        sblock.fs_cstotal.cs_nbfree = 0;
        sblock.fs_cstotal.cs_nifree = 0;
        sblock.fs_cstotal.cs_nffree = 0;
        sblock.fs_fmod = 0;
        sblock.fs_ronly = 0;
        sblock.fs_clean = 1;
#ifdef FSIRAND
        sblock.fs_id[0] = (long)utime;
        sblock.fs_id[1] = random();
#endif

        /*
         * Dump out summary information about file system.
         */
        if (!mfs) {
                printf("%s:\t%d sectors in %d %s of %d tracks, %d sectors\n",
                    fsys, sblock.fs_size * NSPF(&sblock), sblock.fs_ncyl,
                    "cylinders", sblock.fs_ntrak, sblock.fs_nsect);
#define B2MBFACTOR (1 / (1024.0 * 1024.0))
                printf("\t%.1fMB in %d cyl groups (%d c/g, %.2fMB/g, %d i/g)%s\n",
                    (float)sblock.fs_size * sblock.fs_fsize * B2MBFACTOR,
                    sblock.fs_ncg, sblock.fs_cpg,
                    (float)sblock.fs_fpg * sblock.fs_fsize * B2MBFACTOR,
                    sblock.fs_ipg,
                        sblock.fs_flags & FS_DOSOFTDEP ? " SOFTUPDATES" : "");
#undef B2MBFACTOR
        }
        
        if (Eflag && !Nflag) {
                printf("Erasing sectors [%"PRIu64" --- %"PRIu64"]\n",
                    (SBOFF + slice_offset) / sectorsize,
                    fsbtodb(&sblock,sblock.fs_size) -
                    ((SBOFF + slice_offset) / sectorsize) - 1);
                erfs(SBOFF + slice_offset, (fsbtodb(&sblock,sblock.fs_size) -
                    ((SBOFF + slice_offset)/ sectorsize) - 1) *
                    (unsigned long long)sectorsize);
        }
        /*
         * Now build the cylinders group blocks and
         * then print out indices of cylinder groups.
         */
        if (!mfs)
                printf("super-block backups (for fsck -b #) at:\n");
        i = 0;
        width = charsperline();
        for (cylno = 0; cylno < sblock.fs_ncg; cylno++) {
                initcg(cylno, utime);
                if (mfs)
                        continue;
                j = snprintf(tmpbuf, sizeof(tmpbuf), " %ld%s",
                    fsbtodb(&sblock, cgsblock(&sblock, cylno)),
                    cylno < (sblock.fs_ncg-1) ? "," : "" );
                if (i + j >= width) {
                        printf("\n");
                        i = 0;
                }
                i += j;
                printf("%s", tmpbuf);
                fflush(stdout);
        }
        if (!mfs)
                printf("\n");
        if (Nflag && !mfs)
                exit(0);
        /*
         * Now construct the initial file system,
         * then write out the super-block.
         */
        fsinit(utime);
        sblock.fs_time = utime;
        wtfs((int)SBOFF / sectorsize, sbsize, (char *)&sblock);
        for (i = 0; i < sblock.fs_cssize; i += sblock.fs_bsize)
                wtfs(fsbtodb(&sblock, sblock.fs_csaddr + numfrags(&sblock, i)),
                        sblock.fs_cssize - i < sblock.fs_bsize ?
                            sblock.fs_cssize - i : sblock.fs_bsize,
                        ((char *)fscs) + i);
        /*
         * Write out the duplicate super blocks
         */
        for (cylno = 0; cylno < sblock.fs_ncg; cylno++)
                wtfs(fsbtodb(&sblock, cgsblock(&sblock, cylno)),
                    sbsize, (char *)&sblock);
        wtfsflush();

        /*
         * NOTE: we no longer update information in the disklabel
         */

        /*
         * Notify parent process of success.
         * Dissociate from session and tty.
         *
         * NOTE: We are the child and may receive a SIGINT due
         *       to losing the tty session? XXX
         */
        if (mfs) {
                /* YYY */
                kill(mfs_ppid, SIGUSR1);
                setsid();
                close(0);
                close(1);
                close(2);
                chdir("/");
                /* returns to mount_mfs (newfs) and issues the mount */
        }
}

/*
 * Initialize a cylinder group.
 */
void
initcg(int cylno, time_t utime)
{
        daddr_t cbase, d, dlower, dupper, dmax, blkno;
        long i;
        unsigned long k;
        struct csum *cs;
#ifdef FSIRAND
        uint32_t j;
#endif

        /*
         * Determine block bounds for cylinder group.
         * Allow space for super block summary information in first
         * cylinder group.
         */
        cbase = cgbase(&sblock, cylno);
        dmax = cbase + sblock.fs_fpg;
        if (dmax > sblock.fs_size)
                dmax = sblock.fs_size;
        dlower = cgsblock(&sblock, cylno) - cbase;
        dupper = cgdmin(&sblock, cylno) - cbase;
        if (cylno == 0)
                dupper += howmany(sblock.fs_cssize, sblock.fs_fsize);
        cs = fscs + cylno;
        memset(&acg, 0, sblock.fs_cgsize);
        acg.cg_time = utime;
        acg.cg_magic = CG_MAGIC;
        acg.cg_cgx = cylno;
        if (cylno == sblock.fs_ncg - 1)
                acg.cg_ncyl = sblock.fs_ncyl % sblock.fs_cpg;
        else
                acg.cg_ncyl = sblock.fs_cpg;
        acg.cg_niblk = sblock.fs_ipg;
        acg.cg_ndblk = dmax - cbase;
        if (sblock.fs_contigsumsize > 0)
                acg.cg_nclusterblks = acg.cg_ndblk / sblock.fs_frag;
        acg.cg_btotoff = &acg.cg_space[0] - (u_char *)(&acg.cg_firstfield);
        acg.cg_boff = acg.cg_btotoff + sblock.fs_cpg * sizeof(int32_t);
        acg.cg_iusedoff = acg.cg_boff +
                sblock.fs_cpg * sblock.fs_nrpos * sizeof(u_int16_t);
        acg.cg_freeoff = acg.cg_iusedoff + howmany(sblock.fs_ipg, NBBY);
        if (sblock.fs_contigsumsize <= 0) {
                acg.cg_nextfreeoff = acg.cg_freeoff +
                   howmany(sblock.fs_cpg * sblock.fs_spc / NSPF(&sblock), NBBY);
        } else {
                acg.cg_clustersumoff = acg.cg_freeoff + howmany
                    (sblock.fs_cpg * sblock.fs_spc / NSPF(&sblock), NBBY) -
                    sizeof(u_int32_t);
                acg.cg_clustersumoff =
                    roundup(acg.cg_clustersumoff, sizeof(u_int32_t));
                acg.cg_clusteroff = acg.cg_clustersumoff +
                    (sblock.fs_contigsumsize + 1) * sizeof(u_int32_t);
                acg.cg_nextfreeoff = acg.cg_clusteroff + howmany
                    (sblock.fs_cpg * sblock.fs_spc / NSPB(&sblock), NBBY);
        }
        if (acg.cg_nextfreeoff - (long)(&acg.cg_firstfield) > sblock.fs_cgsize) {
                printf("Panic: cylinder group too big\n");
                exit(37);
        }
        acg.cg_cs.cs_nifree += sblock.fs_ipg;
        if (cylno == 0) {
                for (k = 0; k < UFS_ROOTINO; k++) {
                        setbit(cg_inosused(&acg), k);
                        acg.cg_cs.cs_nifree--;
                }
        }
        for (i = 0; i < sblock.fs_ipg / INOPF(&sblock); i += sblock.fs_frag) {
#ifdef FSIRAND
                for (j = 0;
                     j < sblock.fs_bsize / sizeof(struct ufs1_dinode);
                     j++) {
                        zino[j].di_gen = random();
                }
#endif
                wtfs(fsbtodb(&sblock, cgimin(&sblock, cylno) + i),
                    sblock.fs_bsize, (char *)zino);
        }
        if (cylno > 0) {
                /*
                 * In cylno 0, beginning space is reserved
                 * for boot and super blocks.
                 */
                for (d = 0; d < dlower; d += sblock.fs_frag) {
                        blkno = d / sblock.fs_frag;
                        setblock(&sblock, cg_blksfree(&acg), blkno);
                        if (sblock.fs_contigsumsize > 0)
                                setbit(cg_clustersfree(&acg), blkno);
                        acg.cg_cs.cs_nbfree++;
                        cg_blktot(&acg)[cbtocylno(&sblock, d)]++;
                        cg_blks(&sblock, &acg, cbtocylno(&sblock, d))
                            [cbtorpos(&sblock, d)]++;
                }
                sblock.fs_dsize += dlower;
        }
        sblock.fs_dsize += acg.cg_ndblk - dupper;
        if ((i = dupper % sblock.fs_frag)) {
                acg.cg_frsum[sblock.fs_frag - i]++;
                for (d = dupper + sblock.fs_frag - i; dupper < d; dupper++) {
                        setbit(cg_blksfree(&acg), dupper);
                        acg.cg_cs.cs_nffree++;
                }
        }
        for (d = dupper; d + sblock.fs_frag <= dmax - cbase; ) {
                blkno = d / sblock.fs_frag;
                setblock(&sblock, cg_blksfree(&acg), blkno);
                if (sblock.fs_contigsumsize > 0)
                        setbit(cg_clustersfree(&acg), blkno);
                acg.cg_cs.cs_nbfree++;
                cg_blktot(&acg)[cbtocylno(&sblock, d)]++;
                cg_blks(&sblock, &acg, cbtocylno(&sblock, d))
                    [cbtorpos(&sblock, d)]++;
                d += sblock.fs_frag;
        }
        if (d < dmax - cbase) {
                acg.cg_frsum[dmax - cbase - d]++;
                for (; d < dmax - cbase; d++) {
                        setbit(cg_blksfree(&acg), d);
                        acg.cg_cs.cs_nffree++;
                }
        }
        if (sblock.fs_contigsumsize > 0) {
                int32_t *sump = cg_clustersum(&acg);
                u_char *mapp = cg_clustersfree(&acg);
                int map = *mapp++;
                int bit = 1;
                int run = 0;

                for (i = 0; i < acg.cg_nclusterblks; i++) {
                        if ((map & bit) != 0) {
                                run++;
                        } else if (run != 0) {
                                if (run > sblock.fs_contigsumsize)
                                        run = sblock.fs_contigsumsize;
                                sump[run]++;
                                run = 0;
                        }
                        if ((i & (NBBY - 1)) != (NBBY - 1)) {
                                bit <<= 1;
                        } else {
                                map = *mapp++;
                                bit = 1;
                        }
                }
                if (run != 0) {
                        if (run > sblock.fs_contigsumsize)
                                run = sblock.fs_contigsumsize;
                        sump[run]++;
                }
        }
        sblock.fs_cstotal.cs_ndir += acg.cg_cs.cs_ndir;
        sblock.fs_cstotal.cs_nffree += acg.cg_cs.cs_nffree;
        sblock.fs_cstotal.cs_nbfree += acg.cg_cs.cs_nbfree;
        sblock.fs_cstotal.cs_nifree += acg.cg_cs.cs_nifree;
        *cs = acg.cg_cs;
        wtfs(fsbtodb(&sblock, cgtod(&sblock, cylno)),
                sblock.fs_bsize, (char *)&acg);
}

/*
 * initialize the file system
 */
struct ufs1_dinode node;

#ifdef LOSTDIR
#define PREDEFDIR 3
#else
#define PREDEFDIR 2
#endif

struct direct root_dir[] = {
        { UFS_ROOTINO, sizeof(struct direct), DT_DIR, 1, "." },
        { UFS_ROOTINO, sizeof(struct direct), DT_DIR, 2, ".." },
#ifdef LOSTDIR
        { LOSTFOUNDINO, sizeof(struct direct), DT_DIR, 10, "lost+found" },
#endif
};
struct odirect {
        u_long  d_ino;
        u_short d_reclen;
        u_short d_namlen;
        u_char  d_name[MAXNAMLEN + 1];
} oroot_dir[] = {
        { UFS_ROOTINO, sizeof(struct direct), 1, "." },
        { UFS_ROOTINO, sizeof(struct direct), 2, ".." },
#ifdef LOSTDIR
        { LOSTFOUNDINO, sizeof(struct direct), 10, "lost+found" },
#endif
};
#ifdef LOSTDIR
struct direct lost_found_dir[] = {
        { LOSTFOUNDINO, sizeof(struct direct), DT_DIR, 1, "." },
        { UFS_ROOTINO, sizeof(struct direct), DT_DIR, 2, ".." },
        { 0, DIRBLKSIZ, 0, 0, 0 },
};
struct odirect olost_found_dir[] = {
        { LOSTFOUNDINO, sizeof(struct direct), 1, "." },
        { UFS_ROOTINO, sizeof(struct direct), 2, ".." },
        { 0, DIRBLKSIZ, 0, 0 },
};
#endif
char buf[MAXBSIZE];

void
fsinit(time_t utime)
{
#ifdef LOSTDIR
        int i;
#endif

        /*
         * initialize the node
         */
        node.di_atime = utime;
        node.di_mtime = utime;
        node.di_ctime = utime;
#ifdef LOSTDIR
        /*
         * create the lost+found directory
         */
        if (Oflag) {
                makedir((struct direct *)olost_found_dir, 2);
                for (i = DIRBLKSIZ; i < sblock.fs_bsize; i += DIRBLKSIZ)
                        memmove(&buf[i], &olost_found_dir[2],
                            DIRSIZ(0, &olost_found_dir[2]));
        } else {
                makedir(lost_found_dir, 2);
                for (i = DIRBLKSIZ; i < sblock.fs_bsize; i += DIRBLKSIZ)
                        memmove(&buf[i], &lost_found_dir[2],
                            DIRSIZ(0, &lost_found_dir[2]));
        }
        node.di_mode = IFDIR | UMASK;
        node.di_nlink = 2;
        node.di_size = sblock.fs_bsize;
        node.di_db[0] = alloc(node.di_size, node.di_mode);
        node.di_blocks = btodb(fragroundup(&sblock, node.di_size));
        wtfs(fsbtodb(&sblock, node.di_db[0]), node.di_size, buf);
        iput(&node, LOSTFOUNDINO);
#endif
        /*
         * create the root directory
         */
        if (mfs)
                node.di_mode = IFDIR | 01777;
        else
                node.di_mode = IFDIR | UMASK;
        node.di_nlink = PREDEFDIR;
        if (Oflag)
                node.di_size = makedir((struct direct *)oroot_dir, PREDEFDIR);
        else
                node.di_size = makedir(root_dir, PREDEFDIR);
        node.di_db[0] = alloc(sblock.fs_fsize, node.di_mode);
        node.di_blocks = btodb(fragroundup(&sblock, node.di_size));
        wtfs(fsbtodb(&sblock, node.di_db[0]), sblock.fs_fsize, buf);
        iput(&node, UFS_ROOTINO);
}

/*
 * construct a set of directory entries in "buf".
 * return size of directory.
 */
int
makedir(struct direct *protodir, int entries)
{
        char *cp;
        int i, spcleft;

        spcleft = DIRBLKSIZ;
        for (cp = buf, i = 0; i < entries - 1; i++) {
                protodir[i].d_reclen = DIRSIZ(0, &protodir[i]);
                memmove(cp, &protodir[i], protodir[i].d_reclen);
                cp += protodir[i].d_reclen;
                spcleft -= protodir[i].d_reclen;
        }
        protodir[i].d_reclen = spcleft;
        memmove(cp, &protodir[i], DIRSIZ(0, &protodir[i]));
        return (DIRBLKSIZ);
}

/*
 * allocate a block or frag
 */
daddr_t
alloc(int size, int mode)
{
        int i, frag;
        daddr_t d, blkno;

        rdfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize,
            (char *)&acg);
        if (acg.cg_magic != CG_MAGIC) {
                printf("cg 0: bad magic number\n");
                return (0);
        }
        if (acg.cg_cs.cs_nbfree == 0) {
                printf("first cylinder group ran out of space\n");
                return (0);
        }
        for (d = 0; d < acg.cg_ndblk; d += sblock.fs_frag)
                if (isblock(&sblock, cg_blksfree(&acg), d / sblock.fs_frag))
                        goto goth;
        printf("internal error: can't find block in cyl 0\n");
        return (0);
goth:
        blkno = fragstoblks(&sblock, d);
        clrblock(&sblock, cg_blksfree(&acg), blkno);
        if (sblock.fs_contigsumsize > 0)
                clrbit(cg_clustersfree(&acg), blkno);
        acg.cg_cs.cs_nbfree--;
        sblock.fs_cstotal.cs_nbfree--;
        fscs[0].cs_nbfree--;
        if (mode & IFDIR) {
                acg.cg_cs.cs_ndir++;
                sblock.fs_cstotal.cs_ndir++;
                fscs[0].cs_ndir++;
        }
        cg_blktot(&acg)[cbtocylno(&sblock, d)]--;
        cg_blks(&sblock, &acg, cbtocylno(&sblock, d))[cbtorpos(&sblock, d)]--;
        if (size != sblock.fs_bsize) {
                frag = howmany(size, sblock.fs_fsize);
                fscs[0].cs_nffree += sblock.fs_frag - frag;
                sblock.fs_cstotal.cs_nffree += sblock.fs_frag - frag;
                acg.cg_cs.cs_nffree += sblock.fs_frag - frag;
                acg.cg_frsum[sblock.fs_frag - frag]++;
                for (i = frag; i < sblock.fs_frag; i++)
                        setbit(cg_blksfree(&acg), d + i);
        }
        wtfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize,
            (char *)&acg);
        return (d);
}

/*
 * Calculate number of inodes per group.
 */
long
calcipg(long cylspg, long bpcg, off_t *usedbp)
{
        int i;
        long ipg, new_ipg, ncg, ncyl;
        off_t usedb;

        /*
         * Prepare to scale by fssize / (number of sectors in cylinder groups).
         * Note that fssize is still in sectors, not filesystem blocks.
         */
        ncyl = howmany(fssize, (u_int)secpercyl);
        ncg = howmany(ncyl, cylspg);
        /*
         * Iterate a few times to allow for ipg depending on itself.
         */
        ipg = 0;
        for (i = 0; i < 10; i++) {
                usedb = (sblock.fs_iblkno + ipg / INOPF(&sblock))
                        * NSPF(&sblock) * (off_t)sectorsize;
                new_ipg = (cylspg * (quad_t)bpcg - usedb) / density * fssize
                          / ncg / secpercyl / cylspg;
                new_ipg = roundup(new_ipg, INOPB(&sblock));
                if (new_ipg == ipg)
                        break;
                ipg = new_ipg;
        }
        *usedbp = usedb;
        return (ipg);
}

/*
 * Allocate an inode on the disk
 */
void
iput(struct ufs1_dinode *ip, ino_t ino)
{
        struct ufs1_dinode inobuf[MAXINOPB];
        daddr_t d;

#ifdef FSIRAND
        ip->di_gen = random();
#endif
        rdfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize,
            (char *)&acg);
        if (acg.cg_magic != CG_MAGIC) {
                printf("cg 0: bad magic number\n");
                exit(31);
        }
        acg.cg_cs.cs_nifree--;
        setbit(cg_inosused(&acg), ino);
        wtfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize,
            (char *)&acg);
        sblock.fs_cstotal.cs_nifree--;
        fscs[0].cs_nifree--;
        if (ino >= (uint32_t)sblock.fs_ipg * (uint32_t)sblock.fs_ncg) {
                printf("fsinit: inode value out of range (%ju).\n",
                    (uintmax_t)ino);
                exit(32);
        }
        d = fsbtodb(&sblock, ino_to_fsba(&sblock, ino));
        rdfs(d, sblock.fs_bsize, (char *)inobuf);
        inobuf[ino_to_fsbo(&sblock, ino)] = *ip;
        wtfs(d, sblock.fs_bsize, (char *)inobuf);
}

/*
 * Parent notifies child that it can proceed with the newfs and mount
 * operation (occurs after parent has copied the underlying filesystem
 * if the -C option was specified (for MFS), or immediately after the
 * parent forked the child otherwise).
 */
void
parentready(__unused int signo)
{
        parentready_signalled = 1;
}

/*
 * Notify parent process that the filesystem has created itself successfully.
 *
 * We have to wait until the mount has actually completed!
 */
void
started(__unused int signo)
{
        int retry = 100;        /* 10 seconds, 100ms */

        while (mfs_ppid && retry) {
                struct stat st;

                if (
                    stat(mfs_mtpt, &st) < 0 ||
                    st.st_dev != mfs_mtstat.st_dev
                ) {
                        break;
                }
                usleep(100*1000);
                --retry;
        }
        if (retry == 0) {
                fatal("mfs mount failed waiting for mount to go active");
        } else if (copyroot) {
                FSPaste(mfs_mtpt, copyroot, copyhlinks);
        }
        exit(0);
}

/*
 * read a block from the file system
 */
void
rdfs(daddr_t bno, int size, char *bf)
{
        int n;

        wtfsflush();
        if (mfs) {
                memmove(bf, membase + bno * sectorsize, size);
                return;
        }
        if (lseek(fsi, (off_t)bno * sectorsize, 0) < 0) {
                printf("seek error: %ld\n", (long)bno);
                err(33, "rdfs");
        }
        n = read(fsi, bf, size);
        if (n != size) {
                printf("read error: %ld\n", (long)bno);
                err(34, "rdfs");
        }
}

#define WCSIZE (128 * 1024)
daddr_t wc_sect;                /* units of sectorsize */
int wc_end;                     /* bytes */
static char wc[WCSIZE];         /* bytes */

/*
 * Flush dirty write behind buffer.
 */
void
wtfsflush(void)
{
        int n;
        if (wc_end) {
                if (lseek(fso, (off_t)wc_sect * sectorsize, SEEK_SET) < 0) {
                        printf("seek error: %ld\n", (long)wc_sect);
                        err(35, "wtfs - writecombine");
                }
                n = write(fso, wc, wc_end);
                if (n != wc_end) {
                        printf("write error: %ld\n", (long)wc_sect);
                        err(36, "wtfs - writecombine");
                }
                wc_end = 0;
        }
}

/*
 * Issue ioctl to erase range of sectors using TRIM
 */
void
erfs(off_t byte_start, off_t size)
{
        off_t ioarg[2];
        ioarg[0] = byte_start;
        ioarg[1] = size;
        if (ioctl(fsi, DAIOCTRIM, ioarg) < 0) {
                err(37, "Device trim failed\n");
        }
}

/*
 * write a block to the file system
 */
void
wtfs(daddr_t bno, int size, char *bf)
{
        int n;
        int done;

        if (mfs) {
                memmove(membase + bno * sectorsize, bf, size);
                return;
        }
        if (Nflag)
                return;
        done = 0;
        if (wc_end == 0 && size <= WCSIZE) {
                wc_sect = bno;
                bcopy(bf, wc, size);
                wc_end = size;
                if (wc_end < WCSIZE)
                        return;
                done = 1;
        }
        if ((off_t)wc_sect * sectorsize + wc_end == (off_t)bno * sectorsize &&
            wc_end + size <= WCSIZE) {
                bcopy(bf, wc + wc_end, size);
                wc_end += size;
                if (wc_end < WCSIZE)
                        return;
                done = 1;
        }
        wtfsflush();
        if (done)
                return;
        if (lseek(fso, (off_t)bno * sectorsize, SEEK_SET) < 0) {
                printf("seek error: %ld\n", (long)bno);
                err(35, "wtfs");
        }
        n = write(fso, bf, size);
        if (n != size) {
                printf("write error: fso %d blk %ld %d/%d\n", 
                        fso, (long)bno, n, size);
                err(36, "wtfs");
        }
}

/*
 * check if a block is available
 */
int
isblock(struct fs *fs, unsigned char *cp, int h)
{
        unsigned char mask;

        switch (fs->fs_frag) {
        case 8:
                return (cp[h] == 0xff);
        case 4:
                mask = 0x0f << ((h & 0x1) << 2);
                return ((cp[h >> 1] & mask) == mask);
        case 2:
                mask = 0x03 << ((h & 0x3) << 1);
                return ((cp[h >> 2] & mask) == mask);
        case 1:
                mask = 0x01 << (h & 0x7);
                return ((cp[h >> 3] & mask) == mask);
        default:
                fprintf(stderr, "isblock bad fs_frag %d\n", fs->fs_frag);
                return (0);
        }
}

/*
 * take a block out of the map
 */
void
clrblock(struct fs *fs, unsigned char *cp, int h)
{
        switch ((fs)->fs_frag) {
        case 8:
                cp[h] = 0;
                return;
        case 4:
                cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2));
                return;
        case 2:
                cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1));
                return;
        case 1:
                cp[h >> 3] &= ~(0x01 << (h & 0x7));
                return;
        default:
                fprintf(stderr, "clrblock bad fs_frag %d\n", fs->fs_frag);
                return;
        }
}

/*
 * put a block into the map
 */
void
setblock(struct fs *fs, unsigned char *cp, int h)
{
        switch (fs->fs_frag) {
        case 8:
                cp[h] = 0xff;
                return;
        case 4:
                cp[h >> 1] |= (0x0f << ((h & 0x1) << 2));
                return;
        case 2:
                cp[h >> 2] |= (0x03 << ((h & 0x3) << 1));
                return;
        case 1:
                cp[h >> 3] |= (0x01 << (h & 0x7));
                return;
        default:
                fprintf(stderr, "setblock bad fs_frag %d\n", fs->fs_frag);
                return;
        }
}

/*
 * Determine the number of characters in a
 * single line.
 */

static int
charsperline(void)
{
        int columns;
        char *cp;
        struct winsize ws;

        columns = 0;
        if (ioctl(0, TIOCGWINSZ, &ws) != -1)
                columns = ws.ws_col;
        if (columns == 0 && (cp = getenv("COLUMNS")))
                columns = atoi(cp);
        if (columns == 0)
                columns = 80;   /* last resort */
        return columns;
}