/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1982, 1986, 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.
 */

#include <sys/param.h>
#include <sys/endian.h>
#include <sys/limits.h>

#ifndef _KERNEL
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <sys/errno.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ffs/fs.h>

uint32_t calculate_crc32c(uint32_t, const void *, size_t);
uint32_t ffs_calc_sbhash(struct fs *);
struct malloc_type;
#define UFS_MALLOC(size, type, flags) malloc(size)
#define UFS_FREE(ptr, type) free(ptr)
#define maxphys MAXPHYS

#else /* _KERNEL */
#include <sys/systm.h>
#include <sys/gsb_crc32.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/ucred.h>
#include <sys/sysctl.h>

#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/extattr.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/ufs_extern.h>
#include <ufs/ffs/ffs_extern.h>
#include <ufs/ffs/fs.h>

#define UFS_MALLOC(size, type, flags) malloc(size, type, flags)
#define UFS_FREE(ptr, type) free(ptr, type)

#endif /* _KERNEL */

/*
 * Verify an inode check-hash.
 */
int
ffs_verify_dinode_ckhash(struct fs *fs, struct ufs2_dinode *dip)
{
        uint32_t ckhash, save_ckhash;

        /*
         * Return success if unallocated or we are not doing inode check-hash.
         */
        if (dip->di_mode == 0 || (fs->fs_metackhash & CK_INODE) == 0)
                return (0);
        /*
         * Exclude di_ckhash from the crc32 calculation, e.g., always use
         * a check-hash value of zero when calculating the check-hash.
         */
        save_ckhash = dip->di_ckhash;
        dip->di_ckhash = 0;
        ckhash = calculate_crc32c(~0L, (void *)dip, sizeof(*dip));
        dip->di_ckhash = save_ckhash;
        if (save_ckhash == ckhash)
                return (0);
        return (EINVAL);
}

/*
 * Update an inode check-hash.
 */
void
ffs_update_dinode_ckhash(struct fs *fs, struct ufs2_dinode *dip)
{

        if (dip->di_mode == 0 || (fs->fs_metackhash & CK_INODE) == 0)
                return;
        /*
         * Exclude old di_ckhash from the crc32 calculation, e.g., always use
         * a check-hash value of zero when calculating the new check-hash.
         */
        dip->di_ckhash = 0;
        dip->di_ckhash = calculate_crc32c(~0L, (void *)dip, sizeof(*dip));
}

/*
 * These are the low-level functions that actually read and write
 * the superblock and its associated data.
 */
static off_t sblock_try[] = SBLOCKSEARCH;
static int readsuper(void *, struct fs **, off_t, int,
        int (*)(void *, off_t, void **, int));
static void ffs_oldfscompat_read(struct fs *, ufs2_daddr_t);
static int validate_sblock(struct fs *, int);

/*
 * Read a superblock from the devfd device.
 *
 * If an alternate superblock is specified, it is read. Otherwise the
 * set of locations given in the SBLOCKSEARCH list is searched for a
 * superblock. Memory is allocated for the superblock by the readfunc and
 * is returned. If filltype is non-NULL, additional memory is allocated
 * of type filltype and filled in with the superblock summary information.
 * All memory is freed when any error is returned.
 *
 * If a superblock is found, zero is returned. Otherwise one of the
 * following error values is returned:
 *     EIO: non-existent or truncated superblock.
 *     EIO: error reading summary information.
 *     ENOENT: no usable known superblock found.
 *     EILSEQ: filesystem with wrong byte order found.
 *     ENOMEM: failed to allocate space for the superblock.
 *     EINVAL: The previous newfs operation on this volume did not complete.
 *         The administrator must complete newfs before using this volume.
 */
int
ffs_sbget(void *devfd, struct fs **fsp, off_t sblock, int flags,
    struct malloc_type *filltype,
    int (*readfunc)(void *devfd, off_t loc, void **bufp, int size))
{
        struct fs *fs;
        struct fs_summary_info *fs_si;
        int i, error;
        uint64_t size, blks;
        uint8_t *space;
        int32_t *lp;
        char *buf;

        fs = NULL;
        *fsp = NULL;
        if (sblock != UFS_STDSB) {
                if ((error = readsuper(devfd, &fs, sblock,
                    flags | UFS_ALTSBLK, readfunc)) != 0) {
                        if (fs != NULL)
                                UFS_FREE(fs, filltype);
                        return (error);
                }
        } else {
                for (i = 0; sblock_try[i] != -1; i++) {
                        if ((error = readsuper(devfd, &fs, sblock_try[i],
                             flags, readfunc)) == 0) {
                                if ((flags & UFS_NOCSUM) != 0) {
                                        *fsp = fs;
                                        return (0);
                                }
                                break;
                        }
                        if (fs != NULL) {
                                UFS_FREE(fs, filltype);
                                fs = NULL;
                        }
                        if (error == ENOENT)
                                continue;
                        return (error);
                }
                if (sblock_try[i] == -1)
                        return (ENOENT);
        }
        /*
         * Read in the superblock summary information.
         */
        size = fs->fs_cssize;
        blks = howmany(size, fs->fs_fsize);
        if (fs->fs_contigsumsize > 0)
                size += fs->fs_ncg * sizeof(int32_t);
        size += fs->fs_ncg * sizeof(uint8_t);
        if ((fs_si = UFS_MALLOC(sizeof(*fs_si), filltype, M_NOWAIT)) == NULL) {
                UFS_FREE(fs, filltype);
                return (ENOMEM);
        }
        bzero(fs_si, sizeof(*fs_si));
        fs->fs_si = fs_si;
        if ((space = UFS_MALLOC(size, filltype, M_NOWAIT)) == NULL) {
                UFS_FREE(fs->fs_si, filltype);
                UFS_FREE(fs, filltype);
                return (ENOMEM);
        }
        fs->fs_csp = (struct csum *)space;
        for (i = 0; i < blks; i += fs->fs_frag) {
                size = fs->fs_bsize;
                if (i + fs->fs_frag > blks)
                        size = (blks - i) * fs->fs_fsize;
                buf = NULL;
                error = (*readfunc)(devfd,
                    dbtob(fsbtodb(fs, fs->fs_csaddr + i)), (void **)&buf, size);
                if (error) {
                        if (buf != NULL)
                                UFS_FREE(buf, filltype);
                        UFS_FREE(fs->fs_csp, filltype);
                        UFS_FREE(fs->fs_si, filltype);
                        UFS_FREE(fs, filltype);
                        return (error);
                }
                memcpy(space, buf, size);
                UFS_FREE(buf, filltype);
                space += size;
        }
        if (fs->fs_contigsumsize > 0) {
                fs->fs_maxcluster = lp = (int32_t *)space;
                for (i = 0; i < fs->fs_ncg; i++)
                        *lp++ = fs->fs_contigsumsize;
                space = (uint8_t *)lp;
        }
        size = fs->fs_ncg * sizeof(uint8_t);
        fs->fs_contigdirs = (uint8_t *)space;
        bzero(fs->fs_contigdirs, size);
        *fsp = fs;
        return (0);
}

/*
 * Try to read a superblock from the location specified by sblockloc.
 * Return zero on success or an errno on failure.
 */
static int
readsuper(void *devfd, struct fs **fsp, off_t sblockloc, int flags,
    int (*readfunc)(void *devfd, off_t loc, void **bufp, int size))
{
        struct fs *fs;
        int error, res;
        uint32_t ckhash;

        error = (*readfunc)(devfd, sblockloc, (void **)fsp, SBLOCKSIZE);
        if (error != 0)
                return (error);
        fs = *fsp;
        if (fs->fs_magic == FS_BAD_MAGIC)
                return (EINVAL);
        /*
         * For UFS1 with a 65536 block size, the first backup superblock
         * is at the same location as the UFS2 superblock. Since SBLOCK_UFS2
         * is the first location checked, the first backup is the superblock
         * that will be accessed. Here we fail the lookup so that we can
         * retry with the correct location for the UFS1 superblock.
         */
        if (fs->fs_magic == FS_UFS1_MAGIC && (flags & UFS_ALTSBLK) == 0 &&
            fs->fs_bsize == SBLOCK_UFS2 && sblockloc == SBLOCK_UFS2)
                return (ENOENT);
        ffs_oldfscompat_read(fs, sblockloc);
        if ((error = validate_sblock(fs, flags)) > 0)
                return (error);
        /*
         * If the filesystem has been run on a kernel without
         * metadata check hashes, disable them.
         */
        if ((fs->fs_flags & FS_METACKHASH) == 0)
                fs->fs_metackhash = 0;
        /*
         * Clear any check-hashes that are not maintained
         * by this kernel. Also clear any unsupported flags.
         */
        fs->fs_metackhash &= CK_SUPPORTED;
        fs->fs_flags &= FS_SUPPORTED;
        if (fs->fs_ckhash != (ckhash = ffs_calc_sbhash(fs))) {
                if ((flags & (UFS_NOMSG | UFS_NOHASHFAIL)) ==
                    (UFS_NOMSG | UFS_NOHASHFAIL))
                        return (0);
                if ((flags & UFS_NOMSG) != 0)
                        return (EINTEGRITY);
#ifdef _KERNEL
                res = uprintf("Superblock check-hash failed: recorded "
                    "check-hash 0x%x != computed check-hash 0x%x%s\n",
                    fs->fs_ckhash, ckhash,
                    (flags & UFS_NOHASHFAIL) != 0 ? " (Ignored)" : "");
#else
                res = 0;
#endif
                /*
                 * Print check-hash failure if no controlling terminal
                 * in kernel or always if in user-mode (libufs).
                 */
                if (res == 0)
                        printf("Superblock check-hash failed: recorded "
                            "check-hash 0x%x != computed check-hash "
                            "0x%x%s\n", fs->fs_ckhash, ckhash,
                            (flags & UFS_NOHASHFAIL) ? " (Ignored)" : "");
                if ((flags & UFS_NOHASHFAIL) != 0)
                        return (0);
                return (EINTEGRITY);
        }
        /* Have to set for old filesystems that predate this field */
        fs->fs_sblockactualloc = sblockloc;
        /* Not yet any summary information */
        fs->fs_si = NULL;
        return (0);
}

/*
 * Sanity checks for loading old filesystem superblocks.
 * See ffs_oldfscompat_write below for unwound actions.
 *
 * XXX - Parts get retired eventually.
 * Unfortunately new bits get added.
 */
static void
ffs_oldfscompat_read(struct fs *fs, ufs2_daddr_t sblockloc)
{
        uint64_t maxfilesize;

        /*
         * If not yet done, update fs_flags location and value of fs_sblockloc.
         */
        if ((fs->fs_old_flags & FS_FLAGS_UPDATED) == 0) {
                fs->fs_flags = fs->fs_old_flags;
                fs->fs_old_flags |= FS_FLAGS_UPDATED;
                fs->fs_sblockloc = sblockloc;
        }
        switch (fs->fs_magic) {
        case FS_UFS2_MAGIC:
                /* No changes for now */
                break;

        case FS_UFS1_MAGIC:
                /*
                 * If not yet done, update UFS1 superblock with new wider fields
                 */
                if (fs->fs_maxbsize != fs->fs_bsize) {
                        fs->fs_maxbsize = fs->fs_bsize;
                        fs->fs_time = fs->fs_old_time;
                        fs->fs_size = fs->fs_old_size;
                        fs->fs_dsize = fs->fs_old_dsize;
                        fs->fs_csaddr = fs->fs_old_csaddr;
                        fs->fs_cstotal.cs_ndir = fs->fs_old_cstotal.cs_ndir;
                        fs->fs_cstotal.cs_nbfree = fs->fs_old_cstotal.cs_nbfree;
                        fs->fs_cstotal.cs_nifree = fs->fs_old_cstotal.cs_nifree;
                        fs->fs_cstotal.cs_nffree = fs->fs_old_cstotal.cs_nffree;
                }
                if (fs->fs_old_inodefmt < FS_44INODEFMT) {
                        fs->fs_maxfilesize = ((uint64_t)1 << 31) - 1;
                        fs->fs_qbmask = ~fs->fs_bmask;
                        fs->fs_qfmask = ~fs->fs_fmask;
                }
                fs->fs_save_maxfilesize = fs->fs_maxfilesize;
                maxfilesize = (uint64_t)0x80000000 * fs->fs_bsize - 1;
                if (fs->fs_maxfilesize > maxfilesize)
                        fs->fs_maxfilesize = maxfilesize;
                break;
        }
        /* Compatibility for old filesystems */
        if (fs->fs_avgfilesize <= 0)
                fs->fs_avgfilesize = AVFILESIZ;
        if (fs->fs_avgfpdir <= 0)
                fs->fs_avgfpdir = AFPDIR;
}

/*
 * Unwinding superblock updates for old filesystems.
 * See ffs_oldfscompat_read above for details.
 *
 * XXX - Parts get retired eventually.
 * Unfortunately new bits get added.
 */
void
ffs_oldfscompat_write(struct fs *fs)
{

        switch (fs->fs_magic) {
        case FS_UFS1_MAGIC:
                if (fs->fs_sblockloc != SBLOCK_UFS1 &&
                    (fs->fs_old_flags & FS_FLAGS_UPDATED) == 0) {
                        printf(
                        "WARNING: %s: correcting fs_sblockloc from %jd to %d\n",
                            fs->fs_fsmnt, fs->fs_sblockloc, SBLOCK_UFS1);
                        fs->fs_sblockloc = SBLOCK_UFS1;
                }
                /*
                 * Copy back UFS2 updated fields that UFS1 inspects.
                 */
                fs->fs_old_time = fs->fs_time;
                fs->fs_old_cstotal.cs_ndir = fs->fs_cstotal.cs_ndir;
                fs->fs_old_cstotal.cs_nbfree = fs->fs_cstotal.cs_nbfree;
                fs->fs_old_cstotal.cs_nifree = fs->fs_cstotal.cs_nifree;
                fs->fs_old_cstotal.cs_nffree = fs->fs_cstotal.cs_nffree;
                if (fs->fs_save_maxfilesize != 0)
                        fs->fs_maxfilesize = fs->fs_save_maxfilesize;
                break;
        case FS_UFS2_MAGIC:
                if (fs->fs_sblockloc != SBLOCK_UFS2 &&
                    (fs->fs_old_flags & FS_FLAGS_UPDATED) == 0) {
                        printf(
                        "WARNING: %s: correcting fs_sblockloc from %jd to %d\n",
                            fs->fs_fsmnt, fs->fs_sblockloc, SBLOCK_UFS2);
                        fs->fs_sblockloc = SBLOCK_UFS2;
                }
                break;
        }
}

/*
 * Sanity checks for loading old filesystem inodes.
 *
 * XXX - Parts get retired eventually.
 * Unfortunately new bits get added.
 */
static int prttimechgs = 0;
#ifdef _KERNEL
SYSCTL_NODE(_vfs, OID_AUTO, ffs, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "FFS filesystem");
SYSCTL_INT(_vfs_ffs, OID_AUTO, prttimechgs, CTLFLAG_RWTUN, &prttimechgs, 0,
    "print UFS1 time changes made to inodes");
#endif /* _KERNEL */
bool
ffs_oldfscompat_inode_read(struct fs *fs, union dinodep dp, time_t now)
{
        bool change;

        change = false;
        switch (fs->fs_magic) {
        case FS_UFS2_MAGIC:
                /* No changes for now */
                break;

        case FS_UFS1_MAGIC:
                /*
                 * With the change to unsigned time values in UFS1, times set
                 * before Jan 1, 1970 will appear to be in the future. Check
                 * for future times and set them to be the current time.
                 */
                if (dp.dp1->di_ctime > now) {
                        if (prttimechgs)
                                printf("ctime %ud changed to %ld\n",
                                    dp.dp1->di_ctime, (long)now);
                        dp.dp1->di_ctime = now;
                        change = true;
                }
                if (dp.dp1->di_mtime > now) {
                        if (prttimechgs)
                                printf("mtime %ud changed to %ld\n",
                                    dp.dp1->di_mtime, (long)now);
                        dp.dp1->di_mtime = now;
                        dp.dp1->di_ctime = now;
                        change = true;
                }
                if (dp.dp1->di_atime > now) {
                        if (prttimechgs)
                                printf("atime %ud changed to %ld\n",
                                    dp.dp1->di_atime, (long)now);
                        dp.dp1->di_atime = now;
                        dp.dp1->di_ctime = now;
                        change = true;
                }
                break;
        }
        return (change);
}

/*
 * Verify the filesystem values.
 */
#define ILOG2(num)      (fls(num) - 1)
#ifdef STANDALONE_SMALL
#define MPRINT(...)     do { } while (0)
#else
#define MPRINT(...)     if (prtmsg) printf(__VA_ARGS__)
#endif
#define FCHK(lhs, op, rhs, fmt)                                         \
        if (lhs op rhs) {                                               \
                MPRINT("UFS%d superblock failed: %s (" #fmt ") %s %s (" \
                    #fmt ")\n", fs->fs_magic == FS_UFS1_MAGIC ? 1 : 2,  \
                    #lhs, (intmax_t)lhs, #op, #rhs, (intmax_t)rhs);     \
                if (error < 0)                                          \
                        return (ENOENT);                                \
                if (error == 0)                                         \
                        error = ENOENT;                                 \
        }
#define WCHK(lhs, op, rhs, fmt)                                         \
        if (lhs op rhs) {                                               \
                MPRINT("UFS%d superblock failed: %s (" #fmt ") %s %s (" \
                    #fmt ")%s\n", fs->fs_magic == FS_UFS1_MAGIC ? 1 : 2,\
                    #lhs, (intmax_t)lhs, #op, #rhs, (intmax_t)rhs, wmsg);\
                if (error == 0)                                         \
                        error = warnerr;                                \
                if (warnerr == 0)                                       \
                        lhs = rhs;                                      \
        }
#define FCHK2(lhs1, op1, rhs1, lhs2, op2, rhs2, fmt)                    \
        if (lhs1 op1 rhs1 && lhs2 op2 rhs2) {                           \
                MPRINT("UFS%d superblock failed: %s (" #fmt ") %s %s (" \
                    #fmt ") && %s (" #fmt ") %s %s (" #fmt ")\n",       \
                    fs->fs_magic == FS_UFS1_MAGIC ? 1 : 2, #lhs1,       \
                    (intmax_t)lhs1, #op1, #rhs1, (intmax_t)rhs1, #lhs2, \
                    (intmax_t)lhs2, #op2, #rhs2, (intmax_t)rhs2);       \
                if (error < 0)                                          \
                        return (ENOENT);                                \
                if (error == 0)                                         \
                        error = ENOENT;                                 \
        }

static int
validate_sblock(struct fs *fs, int flags)
{
        uint64_t i, sectorsize;
        uint64_t maxfilesize, sizepb;
        int error, prtmsg, warnerr;
        char *wmsg;

        error = 0;
        sectorsize = dbtob(1);
        prtmsg = ((flags & UFS_NOMSG) == 0);
        warnerr = (flags & UFS_NOWARNFAIL) == UFS_NOWARNFAIL ? 0 : ENOENT;
        wmsg = warnerr ? "" : " (Ignored)";
        /*
         * Check for endian mismatch between machine and filesystem.
         */
        if (((fs->fs_magic != FS_UFS2_MAGIC) &&
            (bswap32(fs->fs_magic) == FS_UFS2_MAGIC)) ||
            ((fs->fs_magic != FS_UFS1_MAGIC) &&
            (bswap32(fs->fs_magic) == FS_UFS1_MAGIC))) {
                MPRINT("UFS superblock failed due to endian mismatch "
                    "between machine and filesystem\n");
                return(EILSEQ);
        }
        /*
         * If just validating for recovery, then do just the minimal
         * checks needed for the superblock fields needed to find
         * alternate superblocks.
         */
        if ((flags & UFS_FSRONLY) == UFS_FSRONLY &&
            (fs->fs_magic == FS_UFS1_MAGIC || fs->fs_magic == FS_UFS2_MAGIC)) {
                error = -1; /* fail on first error */
                if (fs->fs_magic == FS_UFS2_MAGIC) {
                        FCHK(fs->fs_sblockloc, !=, SBLOCK_UFS2, %#jx);
                } else if (fs->fs_magic == FS_UFS1_MAGIC) {
                        FCHK(fs->fs_sblockloc, <, 0, %jd);
                        FCHK(fs->fs_sblockloc, >, SBLOCK_UFS1, %jd);
                }
                FCHK(fs->fs_frag, <, 1, %jd);
                FCHK(fs->fs_frag, >, MAXFRAG, %jd);
                FCHK(fs->fs_bsize, <, MINBSIZE, %jd);
                FCHK(fs->fs_bsize, >, MAXBSIZE, %jd);
                FCHK(fs->fs_bsize, <, roundup(sizeof(struct fs), DEV_BSIZE),
                    %jd);
                FCHK(fs->fs_fsize, <, sectorsize, %jd);
                FCHK(fs->fs_fsize * fs->fs_frag, !=, fs->fs_bsize, %jd);
                FCHK(powerof2(fs->fs_fsize), ==, 0, %jd);
                FCHK(fs->fs_sbsize, >, SBLOCKSIZE, %jd);
                FCHK(fs->fs_sbsize, <, (signed)sizeof(struct fs), %jd);
                FCHK(fs->fs_sbsize % sectorsize, !=, 0, %jd);
                FCHK(fs->fs_fpg, <, 3 * fs->fs_frag, %jd);
                FCHK(fs->fs_ncg, <, 1, %jd);
                FCHK(fs->fs_fsbtodb, !=, ILOG2(fs->fs_fsize / sectorsize), %jd);
                FCHK(fs->fs_old_cgoffset, <, 0, %jd);
                FCHK2(fs->fs_old_cgoffset, >, 0, ~fs->fs_old_cgmask, <, 0, %jd);
                FCHK(fs->fs_old_cgoffset * (~fs->fs_old_cgmask), >, fs->fs_fpg,
                    %jd);
                FCHK(fs->fs_sblkno, !=, roundup(
                    howmany(fs->fs_sblockloc + SBLOCKSIZE, fs->fs_fsize),
                    fs->fs_frag), %jd);
                FCHK(CGSIZE(fs), >, fs->fs_bsize, %jd);
                /* Only need to validate these if reading in csum data */
                if ((flags & UFS_NOCSUM) != 0)
                        return (error);
                FCHK((uint64_t)fs->fs_ipg * fs->fs_ncg, >,
                    (((int64_t)(1)) << 32) - INOPB(fs), %jd);
                FCHK(fs->fs_cstotal.cs_nifree, <, 0, %jd);
                FCHK(fs->fs_cstotal.cs_nifree, >,
                    (uint64_t)fs->fs_ipg * fs->fs_ncg, %jd);
                FCHK(fs->fs_cstotal.cs_ndir, >,
                    ((uint64_t)fs->fs_ipg * fs->fs_ncg) -
                    fs->fs_cstotal.cs_nifree, %jd);
                FCHK(fs->fs_size, <, 8 * fs->fs_frag, %jd);
                FCHK(fs->fs_size, <=, ((int64_t)fs->fs_ncg - 1) * fs->fs_fpg,
                    %jd);
                FCHK(fs->fs_size, >, (int64_t)fs->fs_ncg * fs->fs_fpg, %jd);
                FCHK(fs->fs_csaddr, <, 0, %jd);
                FCHK(fs->fs_cssize, !=,
                    fragroundup(fs, fs->fs_ncg * sizeof(struct csum)), %jd);
                FCHK(fs->fs_csaddr + howmany(fs->fs_cssize, fs->fs_fsize), >,
                    fs->fs_size, %jd);
                FCHK(fs->fs_csaddr, <, cgdmin(fs, dtog(fs, fs->fs_csaddr)),
                    %jd);
                FCHK(dtog(fs, fs->fs_csaddr + howmany(fs->fs_cssize,
                    fs->fs_fsize)), >, dtog(fs, fs->fs_csaddr), %jd);
                return (error);
        }
        if (fs->fs_magic == FS_UFS2_MAGIC) {
                if ((flags & UFS_ALTSBLK) == 0)
                        FCHK2(fs->fs_sblockactualloc, !=, SBLOCK_UFS2,
                            fs->fs_sblockactualloc, !=, 0, %jd);
                FCHK(fs->fs_sblockloc, !=, SBLOCK_UFS2, %#jx);
                FCHK(fs->fs_maxsymlinklen, !=, ((UFS_NDADDR + UFS_NIADDR) *
                        sizeof(ufs2_daddr_t)), %jd);
                FCHK(fs->fs_nindir, !=, fs->fs_bsize / sizeof(ufs2_daddr_t),
                    %jd);
                FCHK(fs->fs_inopb, !=,
                    fs->fs_bsize / sizeof(struct ufs2_dinode), %jd);
        } else if (fs->fs_magic == FS_UFS1_MAGIC) {
                if ((flags & UFS_ALTSBLK) == 0)
                        FCHK(fs->fs_sblockactualloc, >, SBLOCK_UFS1, %jd);
                FCHK(fs->fs_sblockloc, <, 0, %jd);
                FCHK(fs->fs_sblockloc, >, SBLOCK_UFS1, %jd);
                FCHK(fs->fs_nindir, !=, fs->fs_bsize / sizeof(ufs1_daddr_t),
                    %jd);
                FCHK(fs->fs_inopb, !=,
                    fs->fs_bsize / sizeof(struct ufs1_dinode), %jd);
                FCHK(fs->fs_maxsymlinklen, !=, ((UFS_NDADDR + UFS_NIADDR) *
                        sizeof(ufs1_daddr_t)), %jd);
                WCHK(fs->fs_old_inodefmt, !=, FS_44INODEFMT, %jd);
                WCHK(fs->fs_old_rotdelay, !=, 0, %jd);
                WCHK(fs->fs_old_rps, !=, 60, %jd);
                WCHK(fs->fs_old_nspf, !=, fs->fs_fsize / sectorsize, %jd);
                WCHK(fs->fs_old_interleave, !=, 1, %jd);
                WCHK(fs->fs_old_trackskew, !=, 0, %jd);
                WCHK(fs->fs_old_cpc, !=, 0, %jd);
                WCHK(fs->fs_old_postblformat, !=, 1, %jd);
                FCHK(fs->fs_old_nrpos, !=, 1, %jd);
                WCHK(fs->fs_old_nsect, !=, fs->fs_old_spc, %jd);
                WCHK(fs->fs_old_npsect, !=, fs->fs_old_spc, %jd);
        } else {
                /* Bad magic number, so assume not a superblock */
                return (ENOENT);
        }
        FCHK(fs->fs_bsize, <, MINBSIZE, %jd);
        FCHK(fs->fs_bsize, >, MAXBSIZE, %jd);
        FCHK(fs->fs_bsize, <, roundup(sizeof(struct fs), DEV_BSIZE), %jd);
        FCHK(powerof2(fs->fs_bsize), ==, 0, %jd);
        FCHK(fs->fs_frag, <, 1, %jd);
        FCHK(fs->fs_frag, >, MAXFRAG, %jd);
        FCHK(fs->fs_frag, !=, numfrags(fs, fs->fs_bsize), %jd);
        FCHK(fs->fs_fsize, <, sectorsize, %jd);
        FCHK(fs->fs_fsize * fs->fs_frag, !=, fs->fs_bsize, %jd);
        FCHK(powerof2(fs->fs_fsize), ==, 0, %jd);
        FCHK(fs->fs_fpg, <, 3 * fs->fs_frag, %jd);
        FCHK(fs->fs_ncg, <, 1, %jd);
        FCHK(fs->fs_ipg, <, fs->fs_inopb, %jd);
        FCHK((uint64_t)fs->fs_ipg * fs->fs_ncg, >,
            (((int64_t)(1)) << 32) - INOPB(fs), %jd);
        FCHK(fs->fs_cstotal.cs_nifree, <, 0, %jd);
        FCHK(fs->fs_cstotal.cs_nifree, >, (uint64_t)fs->fs_ipg * fs->fs_ncg,
            %jd);
        FCHK(fs->fs_cstotal.cs_ndir, <, 0, %jd);
        FCHK(fs->fs_cstotal.cs_ndir, >,
            ((uint64_t)fs->fs_ipg * fs->fs_ncg) - fs->fs_cstotal.cs_nifree,
            %jd);
        FCHK(fs->fs_sbsize, >, SBLOCKSIZE, %jd);
        FCHK(fs->fs_sbsize, <, (signed)sizeof(struct fs), %jd);
        /* fix for misconfigured filesystems */
        if (fs->fs_maxbsize == 0)
                fs->fs_maxbsize = fs->fs_bsize;
        FCHK(fs->fs_maxbsize, <, fs->fs_bsize, %jd);
        FCHK(powerof2(fs->fs_maxbsize), ==, 0, %jd);
        FCHK(fs->fs_maxbsize, >, FS_MAXCONTIG * fs->fs_bsize, %jd);
        FCHK(fs->fs_bmask, !=, ~(fs->fs_bsize - 1), %#jx);
        FCHK(fs->fs_fmask, !=, ~(fs->fs_fsize - 1), %#jx);
        FCHK(fs->fs_qbmask, !=, ~fs->fs_bmask, %#jx);
        FCHK(fs->fs_qfmask, !=, ~fs->fs_fmask, %#jx);
        FCHK(fs->fs_bshift, !=, ILOG2(fs->fs_bsize), %jd);
        FCHK(fs->fs_fshift, !=, ILOG2(fs->fs_fsize), %jd);
        FCHK(fs->fs_fragshift, !=, ILOG2(fs->fs_frag), %jd);
        FCHK(fs->fs_fsbtodb, !=, ILOG2(fs->fs_fsize / sectorsize), %jd);
        FCHK(fs->fs_old_cgoffset, <, 0, %jd);
        FCHK2(fs->fs_old_cgoffset, >, 0, ~fs->fs_old_cgmask, <, 0, %jd);
        FCHK(fs->fs_old_cgoffset * (~fs->fs_old_cgmask), >, fs->fs_fpg, %jd);
        FCHK(CGSIZE(fs), >, fs->fs_bsize, %jd);
        /*
         * If anything has failed up to this point, it is usafe to proceed
         * as checks below may divide by zero or make other fatal calculations.
         * So if we have any errors at this point, give up.
         */
        if (error)
                return (error);
        FCHK(fs->fs_sbsize % sectorsize, !=, 0, %jd);
        FCHK(fs->fs_ipg % fs->fs_inopb, !=, 0, %jd);
        FCHK(fs->fs_sblkno, !=, roundup(
            howmany(fs->fs_sblockloc + SBLOCKSIZE, fs->fs_fsize),
            fs->fs_frag), %jd);
        FCHK(fs->fs_cblkno, !=, fs->fs_sblkno +
            roundup(howmany(SBLOCKSIZE, fs->fs_fsize), fs->fs_frag), %jd);
        FCHK(fs->fs_iblkno, !=, fs->fs_cblkno + fs->fs_frag, %jd);
        FCHK(fs->fs_dblkno, !=, fs->fs_iblkno + fs->fs_ipg / INOPF(fs), %jd);
        FCHK(fs->fs_cgsize, >, fs->fs_bsize, %jd);
        FCHK(fs->fs_cgsize, <, fs->fs_fsize, %jd);
        FCHK(fs->fs_cgsize % fs->fs_fsize, !=, 0, %jd);
        /*
         * This test is valid, however older versions of growfs failed
         * to correctly update fs_dsize so will fail this test. Thus we
         * exclude it from the requirements.
         */
#ifdef notdef
        WCHK(fs->fs_dsize, !=, fs->fs_size - fs->fs_sblkno -
                fs->fs_ncg * (fs->fs_dblkno - fs->fs_sblkno) -
                howmany(fs->fs_cssize, fs->fs_fsize), %jd);
#endif
        WCHK(fs->fs_metaspace, <, 0, %jd);
        WCHK(fs->fs_metaspace, >, fs->fs_fpg / 2, %jd);
        WCHK(fs->fs_minfree, >, 99, %jd%%);
        maxfilesize = fs->fs_bsize * UFS_NDADDR - 1;
        for (sizepb = fs->fs_bsize, i = 0; i < UFS_NIADDR; i++) {
                sizepb *= NINDIR(fs);
                maxfilesize += sizepb;
        }
        WCHK(fs->fs_maxfilesize, >, maxfilesize, %jd);
        /*
         * These values have a tight interaction with each other that
         * makes it hard to tightly bound them. So we can only check
         * that they are within a broader possible range.
         *
         * The size cannot always be accurately determined, but ensure
         * that it is consistent with the number of cylinder groups (fs_ncg)
         * and the number of fragments per cylinder group (fs_fpg). Ensure
         * that the summary information size is correct and that it starts
         * and ends in the data area of the same cylinder group.
         */
        FCHK(fs->fs_size, <, 8 * fs->fs_frag, %jd);
        FCHK(fs->fs_size, <=, ((int64_t)fs->fs_ncg - 1) * fs->fs_fpg, %jd);
        FCHK(fs->fs_size, >, (int64_t)fs->fs_ncg * fs->fs_fpg, %jd);
        /*
         * If we are not requested to read in the csum data stop here
         * as the correctness of the remaining values is only important
         * to bound the space needed to be allocated to hold the csum data.
         */
        if ((flags & UFS_NOCSUM) != 0)
                return (error);
        FCHK(fs->fs_csaddr, <, 0, %jd);
        FCHK(fs->fs_cssize, !=,
            fragroundup(fs, fs->fs_ncg * sizeof(struct csum)), %jd);
        FCHK(fs->fs_csaddr + howmany(fs->fs_cssize, fs->fs_fsize), >,
            fs->fs_size, %jd);
        FCHK(fs->fs_csaddr, <, cgdmin(fs, dtog(fs, fs->fs_csaddr)), %jd);
        FCHK(dtog(fs, fs->fs_csaddr + howmany(fs->fs_cssize, fs->fs_fsize)), >,
            dtog(fs, fs->fs_csaddr), %jd);
        /*
         * With file system clustering it is possible to allocate
         * many contiguous blocks. The kernel variable maxphys defines
         * the maximum transfer size permitted by the controller and/or
         * buffering. The fs_maxcontig parameter controls the maximum
         * number of blocks that the filesystem will read or write
         * in a single transfer. It is calculated when the filesystem
         * is created as maxphys / fs_bsize. The loader uses a maxphys
         * of 128K even when running on a system that supports larger
         * values. If the filesystem was built on a system that supports
         * a larger maxphys (1M is typical) it will have configured
         * fs_maxcontig for that larger system. So we bound the upper
         * allowable limit for fs_maxconfig to be able to at least 
         * work with a 1M maxphys on the smallest block size filesystem:
         * 1M / 4096 == 256. There is no harm in allowing the mounting of
         * filesystems that make larger than maxphys I/O requests because
         * those (mostly 32-bit machines) can (very slowly) handle I/O
         * requests that exceed maxphys.
         */
        WCHK(fs->fs_maxcontig, <, 0, %jd);
        WCHK(fs->fs_maxcontig, >, MAX(256, maxphys / fs->fs_bsize), %jd);
        FCHK2(fs->fs_maxcontig, ==, 0, fs->fs_contigsumsize, !=, 0, %jd);
        FCHK2(fs->fs_maxcontig, >, 1, fs->fs_contigsumsize, !=,
            MIN(fs->fs_maxcontig, FS_MAXCONTIG), %jd);
        return (error);
}

/*
 * Make an extensive search to find a superblock. If the superblock
 * in the standard place cannot be used, try looking for one of the
 * backup superblocks.
 *
 * Flags are made up of the following or'ed together options:
 *
 * UFS_NOMSG indicates that superblock inconsistency error messages
 *    should not be printed.
 *
 * UFS_NOCSUM causes only the superblock itself to be returned, but does
 *    not read in any auxillary data structures like the cylinder group
 *    summary information.
 */
int
ffs_sbsearch(void *devfd, struct fs **fsp, int reqflags,
    struct malloc_type *filltype,
    int (*readfunc)(void *devfd, off_t loc, void **bufp, int size))
{
        struct fsrecovery *fsr;
        struct fs *protofs;
        void *fsrbuf;
        char *cp;
        long nocsum, flags, msg, cg;
        off_t sblk, secsize;
        int error;

        msg = (reqflags & UFS_NOMSG) == 0;
        nocsum = reqflags & UFS_NOCSUM;
        /*
         * Try normal superblock read and return it if it works.
         *
         * Suppress messages if it fails until we find out if
         * failure can be avoided.
         */
        flags = UFS_NOMSG | nocsum;
        error = ffs_sbget(devfd, fsp, UFS_STDSB, flags, filltype, readfunc);
        /*
         * If successful or endian error, no need to try further.
         */
        if (error == 0 || error == EILSEQ) {
                if (msg && error == EILSEQ)
                        printf("UFS superblock failed due to endian mismatch "
                            "between machine and filesystem\n");
                return (error);
        }
        /*
         * First try: ignoring hash failures.
         */
        flags |= UFS_NOHASHFAIL;
        if (msg)
                flags &= ~UFS_NOMSG;
        if (ffs_sbget(devfd, fsp, UFS_STDSB, flags, filltype, readfunc) == 0)
                return (0);
        /*
         * Next up is to check if fields of the superblock that are
         * needed to find backup superblocks are usable.
         */
        if (msg)
                printf("Attempted recovery for standard superblock: failed\n");
        flags = UFS_FSRONLY | UFS_NOHASHFAIL | UFS_NOCSUM | UFS_NOMSG;
        if (ffs_sbget(devfd, &protofs, UFS_STDSB, flags, filltype,
            readfunc) == 0) {
                if (msg)
                        printf("Attempt extraction of recovery data from "
                            "standard superblock.\n");
        } else {
                /*
                 * Final desperation is to see if alternate superblock
                 * parameters have been saved in the boot area.
                 */
                if (msg)
                        printf("Attempted extraction of recovery data from "
                            "standard superblock: failed\nAttempt to find "
                            "boot zone recovery data.\n");
                /*
                 * Look to see if recovery information has been saved.
                 * If so we can generate a prototype superblock based
                 * on that information.
                 *
                 * We need fragments-per-group, number of cylinder groups,
                 * location of the superblock within the cylinder group, and
                 * the conversion from filesystem fragments to disk blocks.
                 *
                 * When building a UFS2 filesystem, newfs(8) stores these
                 * details at the end of the boot block area at the start
                 * of the filesystem partition. If they have been overwritten
                 * by a boot block, we fail.  But usually they are there
                 * and we can use them.
                 *
                 * We could ask the underlying device for its sector size,
                 * but some devices lie. So we just try a plausible range.
                 */
                error = ENOENT;
                fsrbuf = NULL;
                for (secsize = dbtob(1); secsize <= SBLOCKSIZE; secsize *= 2)
                        if ((error = (*readfunc)(devfd, (SBLOCK_UFS2 - secsize),
                            &fsrbuf, secsize)) == 0)
                                break;
                if (error != 0)
                        goto trynowarn;
                cp = fsrbuf; /* type change to keep compiler happy */
                fsr = (struct fsrecovery *)&cp[secsize - sizeof *fsr];
                if (fsr->fsr_magic != FS_UFS2_MAGIC ||
                    (protofs = UFS_MALLOC(SBLOCKSIZE, filltype, M_NOWAIT))
                    == NULL) {
                        UFS_FREE(fsrbuf, filltype);
                        goto trynowarn;
                }
                memset(protofs, 0, sizeof(struct fs));
                protofs->fs_fpg = fsr->fsr_fpg;
                protofs->fs_fsbtodb = fsr->fsr_fsbtodb;
                protofs->fs_sblkno = fsr->fsr_sblkno;
                protofs->fs_magic = fsr->fsr_magic;
                protofs->fs_ncg = fsr->fsr_ncg;
                UFS_FREE(fsrbuf, filltype);
        }
        /*
         * Scan looking for alternative superblocks.
         */
        flags = nocsum;
        if (!msg)
                flags |= UFS_NOMSG;
        for (cg = 0; cg < protofs->fs_ncg; cg++) {
                sblk = fsbtodb(protofs, cgsblock(protofs, cg));
                if (msg)
                        printf("Try cg %ld at sblock loc %jd\n", cg,
                            (intmax_t)sblk);
                if (ffs_sbget(devfd, fsp, dbtob(sblk), flags, filltype,
                    readfunc) == 0) {
                        if (msg)
                                printf("Succeeded with alternate superblock "
                                    "at %jd\n", (intmax_t)sblk);
                        UFS_FREE(protofs, filltype);
                        return (0);
                }
        }
        UFS_FREE(protofs, filltype);
        /*
         * Our alternate superblock strategies failed. Our last ditch effort
         * is to see if the standard superblock has only non-critical errors.
         */
trynowarn:
        flags = UFS_NOWARNFAIL | UFS_NOMSG | nocsum;
        if (msg) {
                printf("Finding an alternate superblock failed.\nCheck for "
                    "only non-critical errors in standard superblock\n");
                flags &= ~UFS_NOMSG;
        }
        if (ffs_sbget(devfd, fsp, UFS_STDSB, flags, filltype, readfunc) != 0) {
                if (msg)
                        printf("Failed, superblock has critical errors\n");
                return (ENOENT);
        }
        if (msg)
                printf("Success, using standard superblock with "
                    "non-critical errors.\n");
        return (0);
}

/*
 * Write a superblock to the devfd device from the memory pointed to by fs.
 * Write out the superblock summary information if it is present.
 *
 * If the write is successful, zero is returned. Otherwise one of the
 * following error values is returned:
 *     EIO: failed to write superblock.
 *     EIO: failed to write superblock summary information.
 */
int
ffs_sbput(void *devfd, struct fs *fs, off_t loc,
    int (*writefunc)(void *devfd, off_t loc, void *buf, int size))
{
        struct fs_summary_info *fs_si;
        int i, error, blks, size;
        uint8_t *space;

        /*
         * If there is summary information, write it first, so if there
         * is an error, the superblock will not be marked as clean.
         */
        if (fs->fs_si != NULL && fs->fs_csp != NULL) {
                blks = howmany(fs->fs_cssize, fs->fs_fsize);
                space = (uint8_t *)fs->fs_csp;
                for (i = 0; i < blks; i += fs->fs_frag) {
                        size = fs->fs_bsize;
                        if (i + fs->fs_frag > blks)
                                size = (blks - i) * fs->fs_fsize;
                        if ((error = (*writefunc)(devfd,
                             dbtob(fsbtodb(fs, fs->fs_csaddr + i)),
                             space, size)) != 0)
                                return (error);
                        space += size;
                }
        }
        fs->fs_fmod = 0;
        ffs_oldfscompat_write(fs);
#ifdef _KERNEL
        fs->fs_time = time_second;
#else /* User Code */
        fs->fs_time = time(NULL);
#endif
        /* Clear the pointers for the duration of writing. */
        fs_si = fs->fs_si;
        fs->fs_si = NULL;
        fs->fs_ckhash = ffs_calc_sbhash(fs);
        error = (*writefunc)(devfd, loc, fs, fs->fs_sbsize);
        /*
         * A negative error code is returned when a copy of the
         * superblock has been made which is discarded when the I/O
         * is done. So the fs_si field does not and indeed cannot be
         * restored after the write is done. Convert the error code
         * back to its usual positive value when returning it.
         */
        if (error < 0)
                return (-error - 1);
        fs->fs_si = fs_si;
        return (error);
}

/*
 * Calculate the check-hash for a superblock.
 */
uint32_t
ffs_calc_sbhash(struct fs *fs)
{
        uint32_t ckhash, save_ckhash;

        /*
         * A filesystem that was using a superblock ckhash may be moved
         * to an older kernel that does not support ckhashes. The
         * older kernel will clear the FS_METACKHASH flag indicating
         * that it does not update hashes. When the disk is moved back
         * to a kernel capable of ckhashes it disables them on mount:
         *
         *      if ((fs->fs_flags & FS_METACKHASH) == 0)
         *              fs->fs_metackhash = 0;
         *
         * This leaves (fs->fs_metackhash & CK_SUPERBLOCK) == 0) with an
         * old stale value in the fs->fs_ckhash field. Thus the need to
         * just accept what is there.
         */
        if ((fs->fs_metackhash & CK_SUPERBLOCK) == 0)
                return (fs->fs_ckhash);

        save_ckhash = fs->fs_ckhash;
        fs->fs_ckhash = 0;
        /*
         * If newly read from disk, the caller is responsible for
         * verifying that fs->fs_sbsize <= SBLOCKSIZE.
         */
        ckhash = calculate_crc32c(~0L, (void *)fs, fs->fs_sbsize);
        fs->fs_ckhash = save_ckhash;
        return (ckhash);
}

/*
 * Update the frsum fields to reflect addition or deletion
 * of some frags.
 */
void
ffs_fragacct(struct fs *fs, int fragmap, int32_t fraglist[], int cnt)
{
        int inblk;
        int field, subfield;
        int siz, pos;

        inblk = (int)(fragtbl[fs->fs_frag][fragmap]) << 1;
        fragmap <<= 1;
        for (siz = 1; siz < fs->fs_frag; siz++) {
                if ((inblk & (1 << (siz + (fs->fs_frag % NBBY)))) == 0)
                        continue;
                field = around[siz];
                subfield = inside[siz];
                for (pos = siz; pos <= fs->fs_frag; pos++) {
                        if ((fragmap & field) == subfield) {
                                fraglist[siz] += cnt;
                                pos += siz;
                                field <<= siz;
                                subfield <<= siz;
                        }
                        field <<= 1;
                        subfield <<= 1;
                }
        }
}

/*
 * block operations
 *
 * check if a block is available
 */
int
ffs_isblock(struct fs *fs, unsigned char *cp, ufs1_daddr_t h)
{
        unsigned char mask;

        switch ((int)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:
#ifdef _KERNEL
                panic("ffs_isblock");
#endif
                break;
        }
        return (0);
}

/*
 * check if a block is free
 */
int
ffs_isfreeblock(struct fs *fs, uint8_t *cp, ufs1_daddr_t h)
{

        switch ((int)fs->fs_frag) {
        case 8:
                return (cp[h] == 0);
        case 4:
                return ((cp[h >> 1] & (0x0f << ((h & 0x1) << 2))) == 0);
        case 2:
                return ((cp[h >> 2] & (0x03 << ((h & 0x3) << 1))) == 0);
        case 1:
                return ((cp[h >> 3] & (0x01 << (h & 0x7))) == 0);
        default:
#ifdef _KERNEL
                panic("ffs_isfreeblock");
#endif
                break;
        }
        return (0);
}

/*
 * take a block out of the map
 */
void
ffs_clrblock(struct fs *fs, uint8_t *cp, ufs1_daddr_t h)
{

        switch ((int)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:
#ifdef _KERNEL
                panic("ffs_clrblock");
#endif
                break;
        }
}

/*
 * put a block into the map
 */
void
ffs_setblock(struct fs *fs, unsigned char *cp, ufs1_daddr_t h)
{

        switch ((int)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:
#ifdef _KERNEL
                panic("ffs_setblock");
#endif
                break;
        }
}

/*
 * Update the cluster map because of an allocation or free.
 *
 * Cnt == 1 means free; cnt == -1 means allocating.
 */
void
ffs_clusteracct(struct fs *fs, struct cg *cgp, ufs1_daddr_t blkno, int cnt)
{
        int32_t *sump;
        int32_t *lp;
        uint8_t *freemapp, *mapp;
        int i, start, end, forw, back, map;
        uint64_t bit;

        if (fs->fs_contigsumsize <= 0)
                return;
        freemapp = cg_clustersfree(cgp);
        sump = cg_clustersum(cgp);
        /*
         * Allocate or clear the actual block.
         */
        if (cnt > 0)
                setbit(freemapp, blkno);
        else
                clrbit(freemapp, blkno);
        /*
         * Find the size of the cluster going forward.
         */
        start = blkno + 1;
        end = start + fs->fs_contigsumsize;
        if (end >= cgp->cg_nclusterblks)
                end = cgp->cg_nclusterblks;
        mapp = &freemapp[start / NBBY];
        map = *mapp++;
        bit = 1U << (start % NBBY);
        for (i = start; i < end; i++) {
                if ((map & bit) == 0)
                        break;
                if ((i & (NBBY - 1)) != (NBBY - 1)) {
                        bit <<= 1;
                } else {
                        map = *mapp++;
                        bit = 1;
                }
        }
        forw = i - start;
        /*
         * Find the size of the cluster going backward.
         */
        start = blkno - 1;
        end = start - fs->fs_contigsumsize;
        if (end < 0)
                end = -1;
        mapp = &freemapp[start / NBBY];
        map = *mapp--;
        bit = 1U << (start % NBBY);
        for (i = start; i > end; i--) {
                if ((map & bit) == 0)
                        break;
                if ((i & (NBBY - 1)) != 0) {
                        bit >>= 1;
                } else {
                        map = *mapp--;
                        bit = 1U << (NBBY - 1);
                }
        }
        back = start - i;
        /*
         * Account for old cluster and the possibly new forward and
         * back clusters.
         */
        i = back + forw + 1;
        if (i > fs->fs_contigsumsize)
                i = fs->fs_contigsumsize;
        sump[i] += cnt;
        if (back > 0)
                sump[back] -= cnt;
        if (forw > 0)
                sump[forw] -= cnt;
        /*
         * Update cluster summary information.
         */
        lp = &sump[fs->fs_contigsumsize];
        for (i = fs->fs_contigsumsize; i > 0; i--)
                if (*lp-- > 0)
                        break;
        fs->fs_maxcluster[cgp->cg_cgx] = i;
}