/*      $OpenBSD: ffs_alloc.c,v 1.115 2024/02/03 18:51:58 beck Exp $    */
/*      $NetBSD: ffs_alloc.c,v 1.11 1996/05/11 18:27:09 mycroft Exp $   */

/*
 * Copyright (c) 2002 Networks Associates Technology, Inc.
 * All rights reserved.
 *
 * This software was developed for the FreeBSD Project by Marshall
 * Kirk McKusick and Network Associates Laboratories, the Security
 * Research Division of Network Associates, Inc. under DARPA/SPAWAR
 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS
 * research program.
 *
 * 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.
 *
 *      @(#)ffs_alloc.c 8.11 (Berkeley) 10/27/94
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/syslog.h>
#include <sys/stdint.h>
#include <sys/time.h>

#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/ufs_extern.h>

#include <ufs/ffs/fs.h>
#include <ufs/ffs/ffs_extern.h>

#define ffs_fserr(fs, uid, cp) do {                             \
        log(LOG_ERR, "uid %u on %s: %s\n", (uid),               \
            (fs)->fs_fsmnt, (cp));                              \
} while (0)

daddr_t         ffs_alloccg(struct inode *, u_int, daddr_t, int);
struct buf *    ffs_cgread(struct fs *, struct inode *, u_int);
daddr_t         ffs_alloccgblk(struct inode *, struct buf *, daddr_t);
ufsino_t        ffs_dirpref(struct inode *);
daddr_t         ffs_fragextend(struct inode *, u_int, daddr_t, int, int);
daddr_t         ffs_hashalloc(struct inode *, u_int, daddr_t, int,
                    daddr_t (*)(struct inode *, u_int, daddr_t, int));
daddr_t         ffs_nodealloccg(struct inode *, u_int, daddr_t, int);
daddr_t         ffs_mapsearch(struct fs *, struct cg *, daddr_t, int);

static const struct timeval     fserr_interval = { 2, 0 };


/*
 * Allocate a block in the file system.
 *
 * The size of the requested block is given, which must be some
 * multiple of fs_fsize and <= fs_bsize.
 * A preference may be optionally specified. If a preference is given
 * the following hierarchy is used to allocate a block:
 *   1) allocate the requested block.
 *   2) allocate a rotationally optimal block in the same cylinder.
 *   3) allocate a block in the same cylinder group.
 *   4) quadratically rehash into other cylinder groups, until an
 *      available block is located.
 * If no block preference is given the following hierarchy is used
 * to allocate a block:
 *   1) allocate a block in the cylinder group that contains the
 *      inode for the file.
 *   2) quadratically rehash into other cylinder groups, until an
 *      available block is located.
 */
int
ffs_alloc(struct inode *ip, daddr_t lbn, daddr_t bpref, int size,
    struct ucred *cred, daddr_t *bnp)
{
        static struct timeval fsfull_last;
        struct fs *fs;
        daddr_t bno;
        u_int cg;
        int error;

        *bnp = 0;
        fs = ip->i_fs;
#ifdef DIAGNOSTIC
        if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0) {
                printf("dev = 0x%x, bsize = %d, size = %d, fs = %s\n",
                    ip->i_dev, fs->fs_bsize, size, fs->fs_fsmnt);
                panic("ffs_alloc: bad size");
        }
        if (cred == NOCRED)
                panic("ffs_alloc: missing credential");
#endif /* DIAGNOSTIC */
        if (size == fs->fs_bsize && fs->fs_cstotal.cs_nbfree == 0)
                goto nospace;
        if (cred->cr_uid != 0 && freespace(fs, fs->fs_minfree) <= 0)
                goto nospace;

        if ((error = ufs_quota_alloc_blocks(ip, btodb(size), cred)) != 0)
                return (error);

        /*
         * Start allocation in the preferred block's cylinder group or
         * the file's inode's cylinder group if no preferred block was
         * specified.
         */
        if (bpref >= fs->fs_size)
                bpref = 0;
        if (bpref == 0)
                cg = ino_to_cg(fs, ip->i_number);
        else
                cg = dtog(fs, bpref);

        /* Try allocating a block. */
        bno = ffs_hashalloc(ip, cg, bpref, size, ffs_alloccg);
        if (bno > 0) {
                /* allocation successful, update inode data */
                DIP_ADD(ip, blocks, btodb(size));
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
                *bnp = bno;
                return (0);
        }

        /* Restore user's disk quota because allocation failed. */
        (void) ufs_quota_free_blocks(ip, btodb(size), cred);

nospace:
        if (ratecheck(&fsfull_last, &fserr_interval)) {
                ffs_fserr(fs, cred->cr_uid, "file system full");
                uprintf("\n%s: write failed, file system is full\n",
                    fs->fs_fsmnt);
        }
        return (ENOSPC);
}

/*
 * Reallocate a fragment to a bigger size
 *
 * The number and size of the old block is given, and a preference
 * and new size is also specified. The allocator attempts to extend
 * the original block. Failing that, the regular block allocator is
 * invoked to get an appropriate block.
 */
int
ffs_realloccg(struct inode *ip, daddr_t lbprev, daddr_t bpref, int osize,
    int nsize, struct ucred *cred, struct buf **bpp, daddr_t *blknop)
{
        static struct timeval fsfull_last;
        struct fs *fs;
        struct buf *bp = NULL;
        daddr_t quota_updated = 0;
        int request, error;
        u_int cg;
        daddr_t bprev, bno;

        if (bpp != NULL)
                *bpp = NULL;
        fs = ip->i_fs;
#ifdef DIAGNOSTIC
        if ((u_int)osize > fs->fs_bsize || fragoff(fs, osize) != 0 ||
            (u_int)nsize > fs->fs_bsize || fragoff(fs, nsize) != 0) {
                printf(
                    "dev = 0x%x, bsize = %d, osize = %d, nsize = %d, fs = %s\n",
                    ip->i_dev, fs->fs_bsize, osize, nsize, fs->fs_fsmnt);
                panic("ffs_realloccg: bad size");
        }
        if (cred == NOCRED)
                panic("ffs_realloccg: missing credential");
#endif /* DIAGNOSTIC */
        if (cred->cr_uid != 0 && freespace(fs, fs->fs_minfree) <= 0)
                goto nospace;

        bprev = DIP(ip, db[lbprev]);

        if (bprev == 0) {
                printf("dev = 0x%x, bsize = %d, bprev = %lld, fs = %s\n",
                    ip->i_dev, fs->fs_bsize, (long long)bprev, fs->fs_fsmnt);
                panic("ffs_realloccg: bad bprev");
        }

        /*
         * Allocate the extra space in the buffer.
         */
        if (bpp != NULL) {
                if ((error = bread(ITOV(ip), lbprev, fs->fs_bsize, &bp)) != 0)
                        goto error;
                buf_adjcnt(bp, osize);
        }

        if ((error = ufs_quota_alloc_blocks(ip, btodb(nsize - osize), cred))
            != 0)
                goto error;

        quota_updated = btodb(nsize - osize);

        /*
         * Check for extension in the existing location.
         */
        cg = dtog(fs, bprev);
        if ((bno = ffs_fragextend(ip, cg, bprev, osize, nsize)) != 0) {
                DIP_ADD(ip, blocks, btodb(nsize - osize));
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
                if (bpp != NULL) {
                        if (bp->b_blkno != fsbtodb(fs, bno))
                                panic("ffs_realloccg: bad blockno");
#ifdef DIAGNOSTIC
                        if (nsize > bp->b_bufsize)
                                panic("ffs_realloccg: small buf");
#endif
                        buf_adjcnt(bp, nsize);
                        bp->b_flags |= B_DONE;
                        memset(bp->b_data + osize, 0, nsize - osize);
                        *bpp = bp;
                }
                if (blknop != NULL) {
                        *blknop = bno;
                }
                return (0);
        }
        /*
         * Allocate a new disk location.
         */
        if (bpref >= fs->fs_size)
                bpref = 0;
        switch (fs->fs_optim) {
        case FS_OPTSPACE:
                /*
                 * Allocate an exact sized fragment. Although this makes
                 * best use of space, we will waste time relocating it if
                 * the file continues to grow. If the fragmentation is
                 * less than half of the minimum free reserve, we choose
                 * to begin optimizing for time.
                 */
                request = nsize;
                if (fs->fs_minfree < 5 ||
                    fs->fs_cstotal.cs_nffree >
                    fs->fs_dsize * fs->fs_minfree / (2 * 100))
                        break;
                fs->fs_optim = FS_OPTTIME;
                break;
        case FS_OPTTIME:
                /*
                 * At this point we have discovered a file that is trying to
                 * grow a small fragment to a larger fragment. To save time,
                 * we allocate a full sized block, then free the unused portion.
                 * If the file continues to grow, the `ffs_fragextend' call
                 * above will be able to grow it in place without further
                 * copying. If aberrant programs cause disk fragmentation to
                 * grow within 2% of the free reserve, we choose to begin
                 * optimizing for space.
                 */
                request = fs->fs_bsize;
                if (fs->fs_cstotal.cs_nffree <
                    fs->fs_dsize * (fs->fs_minfree - 2) / 100)
                        break;
                fs->fs_optim = FS_OPTSPACE;
                break;
        default:
                printf("dev = 0x%x, optim = %d, fs = %s\n",
                    ip->i_dev, fs->fs_optim, fs->fs_fsmnt);
                panic("ffs_realloccg: bad optim");
                /* NOTREACHED */
        }
        bno = ffs_hashalloc(ip, cg, bpref, request, ffs_alloccg);
        if (bno <= 0)
                goto nospace;

        (void) uvm_vnp_uncache(ITOV(ip));
        ffs_blkfree(ip, bprev, (long)osize);
        if (nsize < request)
                ffs_blkfree(ip, bno + numfrags(fs, nsize),
                    (long)(request - nsize));
        DIP_ADD(ip, blocks, btodb(nsize - osize));
        ip->i_flag |= IN_CHANGE | IN_UPDATE;
        if (bpp != NULL) {
                bp->b_blkno = fsbtodb(fs, bno);
#ifdef DIAGNOSTIC
                if (nsize > bp->b_bufsize)
                        panic("ffs_realloccg: small buf 2");
#endif
                buf_adjcnt(bp, nsize);
                bp->b_flags |= B_DONE;
                memset(bp->b_data + osize, 0, nsize - osize);
                *bpp = bp;
        }
        if (blknop != NULL) {
                *blknop = bno;
        }
        return (0);

nospace:
        if (ratecheck(&fsfull_last, &fserr_interval)) {
                ffs_fserr(fs, cred->cr_uid, "file system full");
                uprintf("\n%s: write failed, file system is full\n",
                    fs->fs_fsmnt);
        }
        error = ENOSPC;

error:
        if (bp != NULL) {
                brelse(bp);
                bp = NULL;
        }

        /*
         * Restore user's disk quota because allocation failed.
         */
        if (quota_updated != 0)
                (void)ufs_quota_free_blocks(ip, quota_updated, cred);

        return error;
}

/*
 * Allocate an inode in the file system.
 *
 * If allocating a directory, use ffs_dirpref to select the inode.
 * If allocating in a directory, the following hierarchy is followed:
 *   1) allocate the preferred inode.
 *   2) allocate an inode in the same cylinder group.
 *   3) quadratically rehash into other cylinder groups, until an
 *      available inode is located.
 * If no inode preference is given the following hierarchy is used
 * to allocate an inode:
 *   1) allocate an inode in cylinder group 0.
 *   2) quadratically rehash into other cylinder groups, until an
 *      available inode is located.
 */
int
ffs_inode_alloc(struct inode *pip, mode_t mode, struct ucred *cred,
    struct vnode **vpp)
{
        static struct timeval fsnoinodes_last;
        struct vnode *pvp = ITOV(pip);
        struct fs *fs;
        struct inode *ip;
        ufsino_t ino, ipref;
        u_int cg;
        int error;

        *vpp = NULL;
        fs = pip->i_fs;
        if (fs->fs_cstotal.cs_nifree == 0)
                goto noinodes;

        if ((mode & IFMT) == IFDIR)
                ipref = ffs_dirpref(pip);
        else
                ipref = pip->i_number;
        if (ipref >= fs->fs_ncg * fs->fs_ipg)
                ipref = 0;
        cg = ino_to_cg(fs, ipref);

        /*
         * Track number of dirs created one after another
         * in a same cg without intervening by files.
         */
        if ((mode & IFMT) == IFDIR) {
                if (fs->fs_contigdirs[cg] < 255)
                        fs->fs_contigdirs[cg]++;
        } else {
                if (fs->fs_contigdirs[cg] > 0)
                        fs->fs_contigdirs[cg]--;
        }
        ino = (ufsino_t)ffs_hashalloc(pip, cg, ipref, mode, ffs_nodealloccg);
        if (ino == 0)
                goto noinodes;
        error = VFS_VGET(pvp->v_mount, ino, vpp);
        if (error) {
                ffs_inode_free(pip, ino, mode);
                return (error);
        }

        ip = VTOI(*vpp);

        if (DIP(ip, mode)) {
                printf("mode = 0%o, inum = %u, fs = %s\n",
                    DIP(ip, mode), ip->i_number, fs->fs_fsmnt);
                panic("ffs_valloc: dup alloc");
        }

        if (DIP(ip, blocks)) {
                printf("free inode %s/%d had %lld blocks\n",
                    fs->fs_fsmnt, ino, (long long)DIP(ip, blocks));
                DIP_ASSIGN(ip, blocks, 0);
        }

        DIP_ASSIGN(ip, flags, 0);

        /*
         * Set up a new generation number for this inode.
         * On wrap, we make sure to assign a number != 0 and != UINT_MAX
         * (the original value).
         */
        if (DIP(ip, gen) != 0)
                DIP_ADD(ip, gen, 1);
        while (DIP(ip, gen) == 0)
                DIP_ASSIGN(ip, gen, arc4random_uniform(UINT_MAX));

        return (0);

noinodes:
        if (ratecheck(&fsnoinodes_last, &fserr_interval)) {
                ffs_fserr(fs, cred->cr_uid, "out of inodes");
                uprintf("\n%s: create/symlink failed, no inodes free\n",
                    fs->fs_fsmnt);
        }
        return (ENOSPC);
}

/*
 * Find a cylinder group to place a directory.
 *
 * The policy implemented by this algorithm is to allocate a
 * directory inode in the same cylinder group as its parent
 * directory, but also to reserve space for its files inodes
 * and data. Restrict the number of directories which may be
 * allocated one after another in the same cylinder group
 * without intervening allocation of files.
 *
 * If we allocate a first level directory then force allocation
 * in another cylinder group.
 */
ufsino_t
ffs_dirpref(struct inode *pip)
{
        struct fs *fs;
        u_int   cg, prefcg;
        u_int   dirsize, cgsize;
        u_int   avgifree, avgbfree, avgndir, curdirsize;
        u_int   minifree, minbfree, maxndir;
        u_int   mincg, minndir;
        u_int   maxcontigdirs;

        fs = pip->i_fs;

        avgifree = fs->fs_cstotal.cs_nifree / fs->fs_ncg;
        avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg;
        avgndir = fs->fs_cstotal.cs_ndir / fs->fs_ncg;

        /*
         * Force allocation in another cg if creating a first level dir.
         */
        if (ITOV(pip)->v_flag & VROOT) {
                prefcg = arc4random_uniform(fs->fs_ncg);
                mincg = prefcg;
                minndir = fs->fs_ipg;
                for (cg = prefcg; cg < fs->fs_ncg; cg++)
                        if (fs->fs_cs(fs, cg).cs_ndir < minndir &&
                            fs->fs_cs(fs, cg).cs_nifree >= avgifree &&
                            fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
                                mincg = cg;
                                minndir = fs->fs_cs(fs, cg).cs_ndir;
                        }
                for (cg = 0; cg < prefcg; cg++)
                        if (fs->fs_cs(fs, cg).cs_ndir < minndir &&
                            fs->fs_cs(fs, cg).cs_nifree >= avgifree &&
                            fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
                                mincg = cg;
                                minndir = fs->fs_cs(fs, cg).cs_ndir;
                        }
                cg = mincg;
                goto end;
        } else
                prefcg = ino_to_cg(fs, pip->i_number);

        /*
         * Count various limits which used for
         * optimal allocation of a directory inode.
         */
        maxndir = min(avgndir + fs->fs_ipg / 16, fs->fs_ipg);
        minifree = avgifree - (avgifree / 4);
        if (minifree < 1)
                minifree = 1;
        minbfree = avgbfree - (avgbfree / 4);
        if (minbfree < 1)
                minbfree = 1;

        cgsize = fs->fs_fsize * fs->fs_fpg;
        dirsize = fs->fs_avgfilesize * fs->fs_avgfpdir;
        curdirsize = avgndir ? (cgsize - avgbfree * fs->fs_bsize) / avgndir : 0;
        if (dirsize < curdirsize)
                dirsize = curdirsize;
        if (dirsize <= 0)
                maxcontigdirs = 0;              /* dirsize overflowed */
        else
                maxcontigdirs = min(avgbfree * fs->fs_bsize  / dirsize, 255);
        if (fs->fs_avgfpdir > 0)
                maxcontigdirs = min(maxcontigdirs,
                                    fs->fs_ipg / fs->fs_avgfpdir);
        if (maxcontigdirs == 0)
                maxcontigdirs = 1;

        /*
         * Limit number of dirs in one cg and reserve space for
         * regular files, but only if we have no deficit in
         * inodes or space.
         *
         * We are trying to find a suitable cylinder group nearby
         * our preferred cylinder group to place a new directory.
         * We scan from our preferred cylinder group forward looking
         * for a cylinder group that meets our criterion. If we get
         * to the final cylinder group and do not find anything,
         * we start scanning forwards from the beginning of the
         * filesystem. While it might seem sensible to start scanning
         * backwards or even to alternate looking forward and backward,
         * this approach fails badly when the filesystem is nearly full.
         * Specifically, we first search all the areas that have no space
         * and finally try the one preceding that. We repeat this on
         * every request and in the case of the final block end up
         * searching the entire filesystem. By jumping to the front
         * of the filesystem, our future forward searches always look
         * in new cylinder groups so finds every possible block after
         * one pass over the filesystem.
         */
        for (cg = prefcg; cg < fs->fs_ncg; cg++)
                if (fs->fs_cs(fs, cg).cs_ndir < maxndir &&
                    fs->fs_cs(fs, cg).cs_nifree >= minifree &&
                    fs->fs_cs(fs, cg).cs_nbfree >= minbfree) {
                        if (fs->fs_contigdirs[cg] < maxcontigdirs)
                                goto end;
                }
        for (cg = 0; cg < prefcg; cg++)
                if (fs->fs_cs(fs, cg).cs_ndir < maxndir &&
                    fs->fs_cs(fs, cg).cs_nifree >= minifree &&
                    fs->fs_cs(fs, cg).cs_nbfree >= minbfree) {
                        if (fs->fs_contigdirs[cg] < maxcontigdirs)
                                goto end;
                }
        /*
         * This is a backstop when we have deficit in space.
         */
        for (cg = prefcg; cg < fs->fs_ncg; cg++)
                if (fs->fs_cs(fs, cg).cs_nifree >= avgifree)
                        goto end;
        for (cg = 0; cg < prefcg; cg++)
                if (fs->fs_cs(fs, cg).cs_nifree >= avgifree)
                        goto end;
end:
        return ((ufsino_t)(fs->fs_ipg * cg));
}

/*
 * Select the desired position for the next block in a file.  The file is
 * logically divided into sections. The first section is composed of the
 * direct blocks. Each additional section contains fs_maxbpg blocks.
 *
 * If no blocks have been allocated in the first section, the policy is to
 * request a block in the same cylinder group as the inode that describes
 * the file. The first indirect is allocated immediately following the last
 * direct block and the data blocks for the first indirect immediately
 * follow it.
 *
 * If no blocks have been allocated in any other section, the indirect
 * block(s) are allocated in the same cylinder group as its inode in an
 * area reserved immediately following the inode blocks. The policy for
 * the data blocks is to place them in a cylinder group with a greater than
 * average number of free blocks. An appropriate cylinder group is found
 * by using a rotor that sweeps the cylinder groups. When a new group of
 * blocks is needed, the sweep begins in the cylinder group following the
 * cylinder group from which the previous allocation was made. The sweep
 * continues until a cylinder group with greater than the average number
 * of free blocks is found. If the allocation is for the first block in an
 * indirect block, the information on the previous allocation is unavailable;
 * here a best guess is made based upon the logical block number being
 * allocated.
 */
int32_t
ffs1_blkpref(struct inode *ip, daddr_t lbn, int indx, int32_t *bap)
{
        struct fs *fs;
        u_int cg, inocg;
        u_int avgbfree, startcg;
        uint32_t pref;

        KASSERT(indx <= 0 || bap != NULL);
        fs = ip->i_fs;
        /*
         * Allocation of indirect blocks is indicated by passing negative
         * values in indx: -1 for single indirect, -2 for double indirect,
         * -3 for triple indirect. As noted below, we attempt to allocate
         * the first indirect inline with the file data. For all later
         * indirect blocks, the data is often allocated in other cylinder
         * groups. However to speed random file access and to speed up
         * fsck, the filesystem reserves the first fs_metaspace blocks
         * (typically half of fs_minfree) of the data area of each cylinder
         * group to hold these later indirect blocks.
         */
        inocg = ino_to_cg(fs, ip->i_number);
        if (indx < 0) {
                /*
                 * Our preference for indirect blocks is the zone at the
                 * beginning of the inode's cylinder group data area that
                 * we try to reserve for indirect blocks.
                 */
                pref = cgmeta(fs, inocg);
                /*
                 * If we are allocating the first indirect block, try to
                 * place it immediately following the last direct block.
                 */
                if (indx == -1 && lbn < NDADDR + NINDIR(fs) &&
                    ip->i_din1->di_db[NDADDR - 1] != 0)
                        pref = ip->i_din1->di_db[NDADDR - 1] + fs->fs_frag;
                return (pref);
        }
        /*
         * If we are allocating the first data block in the first indirect
         * block and the indirect has been allocated in the data block area,
         * try to place it immediately following the indirect block.
         */
        if (lbn == NDADDR) {
                pref = ip->i_din1->di_ib[0];
                if (pref != 0 && pref >= cgdata(fs, inocg) &&
                    pref < cgbase(fs, inocg + 1))
                        return (pref + fs->fs_frag);
        }
        /*
         * If we are the beginning of a file, or we have already allocated
         * the maximum number of blocks per cylinder group, or we do not
         * have a block allocated immediately preceding us, then we need
         * to decide where to start allocating new blocks.
         */
        if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) {
                /*
                 * If we are allocating a directory data block, we want
                 * to place it in the metadata area.
                 */
                if ((DIP(ip, mode) & IFMT) == IFDIR)
                        return (cgmeta(fs, inocg));
                /*
                 * Until we fill all the direct and all the first indirect's
                 * blocks, we try to allocate in the data area of the inode's
                 * cylinder group.
                 */
                if (lbn < NDADDR + NINDIR(fs))
                        return (cgdata(fs, inocg));
                /*
                 * Find a cylinder with greater than average number of
                 * unused data blocks.
                 */
                if (indx == 0 || bap[indx - 1] == 0)
                        startcg = inocg + lbn / fs->fs_maxbpg;
                else
                        startcg = dtog(fs, bap[indx - 1]) + 1;
                startcg %= fs->fs_ncg;
                avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg;
                for (cg = startcg; cg < fs->fs_ncg; cg++)
                        if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
                                fs->fs_cgrotor = cg;
                                return (cgdata(fs, cg));
                        }
                for (cg = 0; cg <= startcg; cg++)
                        if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
                                fs->fs_cgrotor = cg;
                                return (cgdata(fs, cg));
                        }
                return (0);
        }
        /*
         * Otherwise, we just always try to lay things out contiguously.
         */
        return (bap[indx - 1] + fs->fs_frag);
}

/*
 * Same as above, for UFS2.
 */
#ifdef FFS2
int64_t
ffs2_blkpref(struct inode *ip, daddr_t lbn, int indx, int64_t *bap)
{
        struct fs *fs;
        u_int cg, inocg;
        u_int avgbfree, startcg;
        uint64_t pref;

        KASSERT(indx <= 0 || bap != NULL);
        fs = ip->i_fs;
        /*
         * Allocation of indirect blocks is indicated by passing negative
         * values in indx: -1 for single indirect, -2 for double indirect,
         * -3 for triple indirect. As noted below, we attempt to allocate
         * the first indirect inline with the file data. For all later
         * indirect blocks, the data is often allocated in other cylinder
         * groups. However to speed random file access and to speed up
         * fsck, the filesystem reserves the first fs_metaspace blocks
         * (typically half of fs_minfree) of the data area of each cylinder
         * group to hold these later indirect blocks.
         */
        inocg = ino_to_cg(fs, ip->i_number);
        if (indx < 0) {
                /*
                 * Our preference for indirect blocks is the zone at the
                 * beginning of the inode's cylinder group data area that
                 * we try to reserve for indirect blocks.
                 */
                pref = cgmeta(fs, inocg);
                /*
                 * If we are allocating the first indirect block, try to
                 * place it immediately following the last direct block.
                 */
                if (indx == -1 && lbn < NDADDR + NINDIR(fs) &&
                    ip->i_din2->di_db[NDADDR - 1] != 0)
                        pref = ip->i_din2->di_db[NDADDR - 1] + fs->fs_frag;
                return (pref);
        }
        /*
         * If we are allocating the first data block in the first indirect
         * block and the indirect has been allocated in the data block area,
         * try to place it immediately following the indirect block.
         */
        if (lbn == NDADDR) {
                pref = ip->i_din2->di_ib[0];
                if (pref != 0 && pref >= cgdata(fs, inocg) &&
                    pref < cgbase(fs, inocg + 1))
                        return (pref + fs->fs_frag);
        }
        /*
         * If we are the beginning of a file, or we have already allocated
         * the maximum number of blocks per cylinder group, or we do not
         * have a block allocated immediately preceding us, then we need
         * to decide where to start allocating new blocks.
         */

        if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) {
                /*
                 * If we are allocating a directory data block, we want
                 * to place it in the metadata area.
                 */
                if ((DIP(ip, mode) & IFMT) == IFDIR)
                        return (cgmeta(fs, inocg));
                /*
                 * Until we fill all the direct and all the first indirect's
                 * blocks, we try to allocate in the data area of the inode's
                 * cylinder group.
                 */
                if (lbn < NDADDR + NINDIR(fs))
                        return (cgdata(fs, inocg));
                /*
                 * Find a cylinder with greater than average number of
                 * unused data blocks.
                 */
                if (indx == 0 || bap[indx - 1] == 0)
                        startcg = inocg + lbn / fs->fs_maxbpg;
                else
                        startcg = dtog(fs, bap[indx - 1] + 1);

                startcg %= fs->fs_ncg;
                avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg;

                for (cg = startcg; cg < fs->fs_ncg; cg++)
                        if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree)
                                return (cgbase(fs, cg) + fs->fs_frag);

                for (cg = 0; cg < startcg; cg++)
                        if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree)
                                return (cgbase(fs, cg) + fs->fs_frag);

                return (0);
        }

        /*
         * Otherwise, we just always try to lay things out contiguously.
         */
        return (bap[indx - 1] + fs->fs_frag);
}
#endif /* FFS2 */

/*
 * Implement the cylinder overflow algorithm.
 *
 * The policy implemented by this algorithm is:
 *   1) allocate the block in its requested cylinder group.
 *   2) quadratically rehash on the cylinder group number.
 *   3) brute force search for a free block.
 */
daddr_t
ffs_hashalloc(struct inode *ip, u_int cg, daddr_t pref, int size,
    daddr_t (*allocator)(struct inode *, u_int, daddr_t, int))
{
        struct fs *fs;
        daddr_t result;
        u_int i, icg = cg;

        fs = ip->i_fs;
        /*
         * 1: preferred cylinder group
         */
        result = (*allocator)(ip, cg, pref, size);
        if (result)
                return (result);
        /*
         * 2: quadratic rehash
         */
        for (i = 1; i < fs->fs_ncg; i *= 2) {
                cg += i;
                if (cg >= fs->fs_ncg)
                        cg -= fs->fs_ncg;
                result = (*allocator)(ip, cg, 0, size);
                if (result)
                        return (result);
        }
        /*
         * 3: brute force search
         * Note that we start at i == 2, since 0 was checked initially,
         * and 1 is always checked in the quadratic rehash.
         */
        cg = (icg + 2) % fs->fs_ncg;
        for (i = 2; i < fs->fs_ncg; i++) {
                result = (*allocator)(ip, cg, 0, size);
                if (result)
                        return (result);
                cg++;
                if (cg == fs->fs_ncg)
                        cg = 0;
        }
        return (0);
}

struct buf *
ffs_cgread(struct fs *fs, struct inode *ip, u_int cg)
{
        struct buf *bp;

        if (bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)),
            (int)fs->fs_cgsize, &bp)) {
                brelse(bp);
                return (NULL);
        }

        if (!cg_chkmagic((struct cg *)bp->b_data)) {
                brelse(bp);
                return (NULL);
        }

        return bp;
}

/*
 * Determine whether a fragment can be extended.
 *
 * Check to see if the necessary fragments are available, and
 * if they are, allocate them.
 */
daddr_t
ffs_fragextend(struct inode *ip, u_int cg, daddr_t bprev, int osize, int nsize)
{
        struct fs *fs;
        struct cg *cgp;
        struct buf *bp;
        struct timespec now;
        daddr_t bno;
        int i, frags, bbase;

        fs = ip->i_fs;
        if (fs->fs_cs(fs, cg).cs_nffree < numfrags(fs, nsize - osize))
                return (0);
        frags = numfrags(fs, nsize);
        bbase = fragnum(fs, bprev);
        if (bbase > fragnum(fs, (bprev + frags - 1))) {
                /* cannot extend across a block boundary */
                return (0);
        }

        if (!(bp = ffs_cgread(fs, ip, cg)))
                return (0);

        cgp = (struct cg *)bp->b_data;
        nanotime(&now);
        cgp->cg_ffs2_time = now.tv_sec;
        cgp->cg_time = now.tv_sec;

        bno = dtogd(fs, bprev);
        for (i = numfrags(fs, osize); i < frags; i++)
                if (isclr(cg_blksfree(cgp), bno + i)) {
                        brelse(bp);
                        return (0);
                }
        /*
         * the current fragment can be extended
         * deduct the count on fragment being extended into
         * increase the count on the remaining fragment (if any)
         * allocate the extended piece
         */
        for (i = frags; i < fs->fs_frag - bbase; i++)
                if (isclr(cg_blksfree(cgp), bno + i))
                        break;
        cgp->cg_frsum[i - numfrags(fs, osize)]--;
        if (i != frags)
                cgp->cg_frsum[i - frags]++;
        for (i = numfrags(fs, osize); i < frags; i++) {
                clrbit(cg_blksfree(cgp), bno + i);
                cgp->cg_cs.cs_nffree--;
                fs->fs_cstotal.cs_nffree--;
                fs->fs_cs(fs, cg).cs_nffree--;
        }
        fs->fs_fmod = 1;

        bdwrite(bp);
        return (bprev);
}

/*
 * Determine whether a block can be allocated.
 *
 * Check to see if a block of the appropriate size is available,
 * and if it is, allocate it.
 */
daddr_t
ffs_alloccg(struct inode *ip, u_int cg, daddr_t bpref, int size)
{
        struct fs *fs;
        struct cg *cgp;
        struct buf *bp;
        struct timespec now;
        daddr_t bno, blkno;
        int i, frags, allocsiz;

        fs = ip->i_fs;
        if (fs->fs_cs(fs, cg).cs_nbfree == 0 && size == fs->fs_bsize)
                return (0);

        if (!(bp = ffs_cgread(fs, ip, cg)))
                return (0);

        cgp = (struct cg *)bp->b_data;
        if (cgp->cg_cs.cs_nbfree == 0 && size == fs->fs_bsize) {
                brelse(bp);
                return (0);
        }

        nanotime(&now);
        cgp->cg_ffs2_time = now.tv_sec;
        cgp->cg_time = now.tv_sec;

        if (size == fs->fs_bsize) {
                /* allocate and return a complete data block */
                bno = ffs_alloccgblk(ip, bp, bpref);
                bdwrite(bp);
                return (bno);
        }
        /*
         * check to see if any fragments are already available
         * allocsiz is the size which will be allocated, hacking
         * it down to a smaller size if necessary
         */
        frags = numfrags(fs, size);
        for (allocsiz = frags; allocsiz < fs->fs_frag; allocsiz++)
                if (cgp->cg_frsum[allocsiz] != 0)
                        break;
        if (allocsiz == fs->fs_frag) {
                /*
                 * no fragments were available, so a block will be
                 * allocated, and hacked up
                 */
                if (cgp->cg_cs.cs_nbfree == 0) {
                        brelse(bp);
                        return (0);
                }
                bno = ffs_alloccgblk(ip, bp, bpref);
                bpref = dtogd(fs, bno);
                for (i = frags; i < fs->fs_frag; i++)
                        setbit(cg_blksfree(cgp), bpref + i);
                i = fs->fs_frag - frags;
                cgp->cg_cs.cs_nffree += i;
                fs->fs_cstotal.cs_nffree += i;
                fs->fs_cs(fs, cg).cs_nffree += i;
                fs->fs_fmod = 1;
                cgp->cg_frsum[i]++;
                bdwrite(bp);
                return (bno);
        }
        bno = ffs_mapsearch(fs, cgp, bpref, allocsiz);
        if (bno < 0) {
                brelse(bp);
                return (0);
        }

        for (i = 0; i < frags; i++)
                clrbit(cg_blksfree(cgp), bno + i);
        cgp->cg_cs.cs_nffree -= frags;
        fs->fs_cstotal.cs_nffree -= frags;
        fs->fs_cs(fs, cg).cs_nffree -= frags;
        fs->fs_fmod = 1;
        cgp->cg_frsum[allocsiz]--;
        if (frags != allocsiz)
                cgp->cg_frsum[allocsiz - frags]++;

        blkno = cgbase(fs, cg) + bno;
        bdwrite(bp);
        return (blkno);
}

/*
 * Allocate a block in a cylinder group.
 * Note that this routine only allocates fs_bsize blocks; these
 * blocks may be fragmented by the routine that allocates them.
 */
daddr_t
ffs_alloccgblk(struct inode *ip, struct buf *bp, daddr_t bpref)
{
        struct fs *fs;
        struct cg *cgp;
        daddr_t bno, blkno;
        u_int8_t *blksfree;
        int cylno, cgbpref;

        fs = ip->i_fs;
        cgp = (struct cg *) bp->b_data;
        blksfree = cg_blksfree(cgp);

        if (bpref == 0) {
                bpref = cgp->cg_rotor;
        } else if ((cgbpref = dtog(fs, bpref)) != cgp->cg_cgx) {
                /* map bpref to correct zone in this cg */
                if (bpref < cgdata(fs, cgbpref))
                        bpref = cgmeta(fs, cgp->cg_cgx);
                else
                        bpref = cgdata(fs, cgp->cg_cgx);
        }
        /*
         * If the requested block is available, use it.
         */
        bno = dtogd(fs, blknum(fs, bpref));
        if (ffs_isblock(fs, blksfree, fragstoblks(fs, bno)))
                goto gotit;
        /*
         * Take the next available block in this cylinder group.
         */
        bno = ffs_mapsearch(fs, cgp, bpref, (int) fs->fs_frag);
        if (bno < 0)
                return (0);

        /* Update cg_rotor only if allocated from the data zone */
        if (bno >= dtogd(fs, cgdata(fs, cgp->cg_cgx)))
                cgp->cg_rotor = bno;

gotit:
        blkno = fragstoblks(fs, bno);
        ffs_clrblock(fs, blksfree, blkno);
        ffs_clusteracct(fs, cgp, blkno, -1);
        cgp->cg_cs.cs_nbfree--;
        fs->fs_cstotal.cs_nbfree--;
        fs->fs_cs(fs, cgp->cg_cgx).cs_nbfree--;

        if (fs->fs_magic != FS_UFS2_MAGIC) {
                cylno = cbtocylno(fs, bno);
                cg_blks(fs, cgp, cylno)[cbtorpos(fs, bno)]--;
                cg_blktot(cgp)[cylno]--;
        }

        fs->fs_fmod = 1;
        blkno = cgbase(fs, cgp->cg_cgx) + bno;

        return (blkno);
}

/* inode allocation routine */
daddr_t
ffs_nodealloccg(struct inode *ip, u_int cg, daddr_t ipref, int mode)
{
        struct fs *fs;
        struct cg *cgp;
        struct buf *bp;
        struct timespec now;
        int start, len, loc, map, i;
#ifdef FFS2
        struct buf *ibp = NULL;
        struct ufs2_dinode *dp2;
#endif

        /*
         * For efficiency, before looking at the bitmaps for free inodes,
         * check the counters kept in the superblock cylinder group summaries,
         * and in the cylinder group itself.
         */
        fs = ip->i_fs;
        if (fs->fs_cs(fs, cg).cs_nifree == 0)
                return (0);

        if (!(bp = ffs_cgread(fs, ip, cg)))
                return (0);

        cgp = (struct cg *)bp->b_data;
        if (cgp->cg_cs.cs_nifree == 0) {
                brelse(bp);
                return (0);
        }

        /*
         * We are committed to the allocation from now on, so update the time
         * on the cylinder group.
         */
        nanotime(&now);
        cgp->cg_ffs2_time = now.tv_sec;
        cgp->cg_time = now.tv_sec;

        /*
         * If there was a preferred location for the new inode, try to find it.
         */
        if (ipref) {
                ipref %= fs->fs_ipg;
                if (isclr(cg_inosused(cgp), ipref))
                        goto gotit; /* inode is free, grab it. */
        }

        /*
         * Otherwise, look for the next available inode, starting at cg_irotor
         * (the position in the bitmap of the last used inode).
         */
        start = cgp->cg_irotor / NBBY;
        len = howmany(fs->fs_ipg - cgp->cg_irotor, NBBY);
        loc = skpc(0xff, len, &cg_inosused(cgp)[start]);
        if (loc == 0) {
                /*
                 * If we didn't find a free inode in the upper part of the
                 * bitmap (from cg_irotor to the end), then look at the bottom
                 * part (from 0 to cg_irotor).
                 */
                len = start + 1;
                start = 0;
                loc = skpc(0xff, len, &cg_inosused(cgp)[0]);
                if (loc == 0) {
                        /*
                         * If we failed again, then either the bitmap or the
                         * counters kept for the cylinder group are wrong.
                         */
                        printf("cg = %d, irotor = %d, fs = %s\n",
                            cg, cgp->cg_irotor, fs->fs_fsmnt);
                        panic("ffs_nodealloccg: map corrupted");
                        /* NOTREACHED */
                }
        }

        /* skpc() returns the position relative to the end */
        i = start + len - loc;

        /*
         * Okay, so now in 'i' we have the location in the bitmap of a byte
         * holding a free inode. Find the corresponding bit and set it,
         * updating cg_irotor as well, accordingly.
         */
        map = cg_inosused(cgp)[i];
        ipref = i * NBBY;
        for (i = 1; i < (1 << NBBY); i <<= 1, ipref++) {
                if ((map & i) == 0) {
                        cgp->cg_irotor = ipref;
                        goto gotit;
                }
        }

        printf("fs = %s\n", fs->fs_fsmnt);
        panic("ffs_nodealloccg: block not in map");
        /* NOTREACHED */

gotit:

#ifdef FFS2
        /*
         * For FFS2, check if all inodes in this cylinder group have been used
         * at least once. If they haven't, and we are allocating an inode past
         * the last allocated block of inodes, read in a block and initialize
         * all inodes in it.
         */
        if (fs->fs_magic == FS_UFS2_MAGIC &&
            /* Inode is beyond last initialized block of inodes? */
            ipref + INOPB(fs) > cgp->cg_initediblk &&
            /* Has any inode not been used at least once? */
            cgp->cg_initediblk < cgp->cg_ffs2_niblk) {

                ibp = getblk(ip->i_devvp, fsbtodb(fs,
                    ino_to_fsba(fs, cg * fs->fs_ipg + cgp->cg_initediblk)),
                    (int)fs->fs_bsize, 0, INFSLP);

                memset(ibp->b_data, 0, fs->fs_bsize);
                dp2 = (struct ufs2_dinode *)(ibp->b_data);

                /* Give each inode a generation number */
                for (i = 0; i < INOPB(fs); i++) {
                        while (dp2->di_gen == 0)
                                dp2->di_gen = arc4random();
                        dp2++;
                }

                /* Update the counter of initialized inodes */
                cgp->cg_initediblk += INOPB(fs);
        }
#endif /* FFS2 */

        setbit(cg_inosused(cgp), ipref);

        /* Update the counters we keep on free inodes */
        cgp->cg_cs.cs_nifree--;
        fs->fs_cstotal.cs_nifree--;
        fs->fs_cs(fs, cg).cs_nifree--;
        fs->fs_fmod = 1; /* file system was modified */

        /* Update the counters we keep on allocated directories */
        if ((mode & IFMT) == IFDIR) {
                cgp->cg_cs.cs_ndir++;
                fs->fs_cstotal.cs_ndir++;
                fs->fs_cs(fs, cg).cs_ndir++;
        }

        bdwrite(bp);

#ifdef FFS2
        if (ibp != NULL)
                bawrite(ibp);
#endif

        /* Return the allocated inode number */
        return (cg * fs->fs_ipg + ipref);
}

/*
 * Free a block or fragment.
 *
 * The specified block or fragment is placed back in the
 * free map. If a fragment is deallocated, a possible
 * block reassembly is checked.
 */
void
ffs_blkfree(struct inode *ip, daddr_t bno, long size)
{
        struct fs *fs;
        struct cg *cgp;
        struct buf *bp;
        struct timespec now;
        daddr_t blkno;
        int i, cg, blk, frags, bbase;

        fs = ip->i_fs;
        if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0 ||
            fragnum(fs, bno) + numfrags(fs, size) > fs->fs_frag) {
                printf("dev = 0x%x, bsize = %d, size = %ld, fs = %s\n",
                    ip->i_dev, fs->fs_bsize, size, fs->fs_fsmnt);
                panic("ffs_blkfree: bad size");
        }
        cg = dtog(fs, bno);
        if ((u_int)bno >= fs->fs_size) {
                printf("bad block %lld, ino %u\n", (long long)bno,
                    ip->i_number);
                ffs_fserr(fs, DIP(ip, uid), "bad block");
                return;
        }
        if (!(bp = ffs_cgread(fs, ip, cg)))
                return;

        cgp = (struct cg *)bp->b_data;
        nanotime(&now);
        cgp->cg_ffs2_time = now.tv_sec;
        cgp->cg_time = now.tv_sec;

        bno = dtogd(fs, bno);
        if (size == fs->fs_bsize) {
                blkno = fragstoblks(fs, bno);
                if (!ffs_isfreeblock(fs, cg_blksfree(cgp), blkno)) {
                        printf("dev = 0x%x, block = %lld, fs = %s\n",
                            ip->i_dev, (long long)bno, fs->fs_fsmnt);
                        panic("ffs_blkfree: freeing free block");
                }
                ffs_setblock(fs, cg_blksfree(cgp), blkno);
                ffs_clusteracct(fs, cgp, blkno, 1);
                cgp->cg_cs.cs_nbfree++;
                fs->fs_cstotal.cs_nbfree++;
                fs->fs_cs(fs, cg).cs_nbfree++;

                if (fs->fs_magic != FS_UFS2_MAGIC) {
                        i = cbtocylno(fs, bno);
                        cg_blks(fs, cgp, i)[cbtorpos(fs, bno)]++;
                        cg_blktot(cgp)[i]++;
                }

        } else {
                bbase = bno - fragnum(fs, bno);
                /*
                 * decrement the counts associated with the old frags
                 */
                blk = blkmap(fs, cg_blksfree(cgp), bbase);
                ffs_fragacct(fs, blk, cgp->cg_frsum, -1);
                /*
                 * deallocate the fragment
                 */
                frags = numfrags(fs, size);
                for (i = 0; i < frags; i++) {
                        if (isset(cg_blksfree(cgp), bno + i)) {
                                printf("dev = 0x%x, block = %lld, fs = %s\n",
                                    ip->i_dev, (long long)(bno + i),
                                    fs->fs_fsmnt);
                                panic("ffs_blkfree: freeing free frag");
                        }
                        setbit(cg_blksfree(cgp), bno + i);
                }
                cgp->cg_cs.cs_nffree += i;
                fs->fs_cstotal.cs_nffree += i;
                fs->fs_cs(fs, cg).cs_nffree += i;
                /*
                 * add back in counts associated with the new frags
                 */
                blk = blkmap(fs, cg_blksfree(cgp), bbase);
                ffs_fragacct(fs, blk, cgp->cg_frsum, 1);
                /*
                 * if a complete block has been reassembled, account for it
                 */
                blkno = fragstoblks(fs, bbase);
                if (ffs_isblock(fs, cg_blksfree(cgp), blkno)) {
                        cgp->cg_cs.cs_nffree -= fs->fs_frag;
                        fs->fs_cstotal.cs_nffree -= fs->fs_frag;
                        fs->fs_cs(fs, cg).cs_nffree -= fs->fs_frag;
                        ffs_clusteracct(fs, cgp, blkno, 1);
                        cgp->cg_cs.cs_nbfree++;
                        fs->fs_cstotal.cs_nbfree++;
                        fs->fs_cs(fs, cg).cs_nbfree++;

                        if (fs->fs_magic != FS_UFS2_MAGIC) {
                                i = cbtocylno(fs, bbase);
                                cg_blks(fs, cgp, i)[cbtorpos(fs, bbase)]++;
                                cg_blktot(cgp)[i]++;
                        }
                }
        }
        fs->fs_fmod = 1;
        bdwrite(bp);
}

int
ffs_inode_free(struct inode *pip, ufsino_t ino, mode_t mode)
{
        return (ffs_freefile(pip, ino, mode));
}

/*
 * Do the actual free operation.
 * The specified inode is placed back in the free map.
 */
int
ffs_freefile(struct inode *pip, ufsino_t ino, mode_t mode)
{
        struct fs *fs;
        struct cg *cgp;
        struct buf *bp;
        struct timespec now;
        u_int cg;

        fs = pip->i_fs;
        if (ino >= fs->fs_ipg * fs->fs_ncg)
                panic("ffs_freefile: range: dev = 0x%x, ino = %d, fs = %s",
                    pip->i_dev, ino, fs->fs_fsmnt);

        cg = ino_to_cg(fs, ino);
        if (!(bp = ffs_cgread(fs, pip, cg)))
                return (0);

        cgp = (struct cg *)bp->b_data;
        nanotime(&now);
        cgp->cg_ffs2_time = now.tv_sec;
        cgp->cg_time = now.tv_sec;

        ino %= fs->fs_ipg;
        if (isclr(cg_inosused(cgp), ino)) {
                printf("dev = 0x%x, ino = %u, fs = %s\n",
                    pip->i_dev, ino, fs->fs_fsmnt);
                if (fs->fs_ronly == 0)
                        panic("ffs_freefile: freeing free inode");
        }
        clrbit(cg_inosused(cgp), ino);
        if (ino < cgp->cg_irotor)
                cgp->cg_irotor = ino;
        cgp->cg_cs.cs_nifree++;
        fs->fs_cstotal.cs_nifree++;
        fs->fs_cs(fs, cg).cs_nifree++;
        if ((mode & IFMT) == IFDIR) {
                cgp->cg_cs.cs_ndir--;
                fs->fs_cstotal.cs_ndir--;
                fs->fs_cs(fs, cg).cs_ndir--;
        }
        fs->fs_fmod = 1;
        bdwrite(bp);
        return (0);
}


/*
 * Find a block of the specified size in the specified cylinder group.
 *
 * It is a panic if a request is made to find a block if none are
 * available.
 */
daddr_t
ffs_mapsearch(struct fs *fs, struct cg *cgp, daddr_t bpref, int allocsiz)
{
        daddr_t bno;
        int start, len, loc, i;
        int blk, field, subfield, pos;

        /*
         * find the fragment by searching through the free block
         * map for an appropriate bit pattern
         */
        if (bpref)
                start = dtogd(fs, bpref) / NBBY;
        else
                start = cgp->cg_frotor / NBBY;
        len = howmany(fs->fs_fpg, NBBY) - start;
        loc = scanc((u_int)len, (u_char *)&cg_blksfree(cgp)[start],
                (u_char *)fragtbl[fs->fs_frag],
                (u_char)(1 << (allocsiz - 1 + (fs->fs_frag % NBBY))));
        if (loc == 0) {
                len = start + 1;
                start = 0;
                loc = scanc((u_int)len, (u_char *)&cg_blksfree(cgp)[0],
                        (u_char *)fragtbl[fs->fs_frag],
                        (u_char)(1 << (allocsiz - 1 + (fs->fs_frag % NBBY))));
                if (loc == 0) {
                        printf("start = %d, len = %d, fs = %s\n",
                            start, len, fs->fs_fsmnt);
                        panic("ffs_alloccg: map corrupted");
                        /* NOTREACHED */
                }
        }
        bno = (start + len - loc) * NBBY;
        cgp->cg_frotor = bno;
        /*
         * found the byte in the map
         * sift through the bits to find the selected frag
         */
        for (i = bno + NBBY; bno < i; bno += fs->fs_frag) {
                blk = blkmap(fs, cg_blksfree(cgp), bno);
                blk <<= 1;
                field = around[allocsiz];
                subfield = inside[allocsiz];
                for (pos = 0; pos <= fs->fs_frag - allocsiz; pos++) {
                        if ((blk & field) == subfield)
                                return (bno + pos);
                        field <<= 1;
                        subfield <<= 1;
                }
        }
        printf("bno = %lld, fs = %s\n", (long long)bno, fs->fs_fsmnt);
        panic("ffs_alloccg: block not in map");
        return (-1);
}

/*
 * 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, daddr_t blkno, int cnt)
{
        int32_t *sump;
        int32_t *lp;
        u_char *freemapp, *mapp;
        int i, start, end, forw, back, map, 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 = 1 << (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 = 1 << (start % NBBY);
        for (i = start; i > end; i--) {
                if ((map & bit) == 0)
                        break;
                if ((i & (NBBY - 1)) != 0) {
                        bit >>= 1;
                } else {
                        map = *mapp--;
                        bit = 1 << (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;
}