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

[dragonfly.git] / sys / vfs / ufs / ffs_alloc.c

/*
 * 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 8.18 (Berkeley) 5/26/95
 * $FreeBSD: src/sys/ufs/ffs/ffs_alloc.c,v 1.64.2.2 2001/09/21 19:15:21 dillon Exp $
 */

#include "opt_quota.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>

#include <sys/taskqueue.h>
#include <machine/inttypes.h>

#include <sys/buf2.h>

#include "quota.h"
#include "inode.h"
#include "ufs_extern.h"
#include "ufsmount.h"

#include "fs.h"
#include "ffs_extern.h"

typedef ufs_daddr_t allocfcn_t (struct inode *ip, int cg, ufs_daddr_t bpref,
                                  int size);

static ufs_daddr_t ffs_alloccg (struct inode *, int, ufs_daddr_t, int);
static ufs_daddr_t
              ffs_alloccgblk (struct inode *, struct buf *, ufs_daddr_t);
static void ffs_blkfree_cg(struct fs *, struct vnode *, cdev_t , ino_t,
                           uint32_t , ufs_daddr_t, long );
#ifdef DIAGNOSTIC
static int      ffs_checkblk (struct inode *, ufs_daddr_t, long);
#endif
static void     ffs_clusteracct (struct fs *, struct cg *, ufs_daddr_t,
                                     int);
static ufs_daddr_t ffs_clusteralloc (struct inode *, int, ufs_daddr_t,
            int);
static ino_t    ffs_dirpref (struct inode *);
static ufs_daddr_t ffs_fragextend (struct inode *, int, long, int, int);
static void     ffs_fserr (struct fs *, uint, char *);
static u_long   ffs_hashalloc
                    (struct inode *, int, long, int, allocfcn_t *);
static ino_t    ffs_nodealloccg (struct inode *, int, ufs_daddr_t, int);
static ufs_daddr_t ffs_mapsearch (struct fs *, struct cg *, ufs_daddr_t,
            int);

/*
 * Allocate a block in the filesystem.
 *
 * 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) quadradically rehash into other cylinder groups, until an
 *      available block is located.
 * If no block preference is given the following heirarchy is used
 * to allocate a block:
 *   1) allocate a block in the cylinder group that contains the
 *      inode for the file.
 *   2) quadradically rehash into other cylinder groups, until an
 *      available block is located.
 */
int
ffs_alloc(struct inode *ip, ufs_daddr_t lbn, ufs_daddr_t bpref, int size,
          struct ucred *cred, ufs_daddr_t *bnp)
{
        struct fs *fs;
        ufs_daddr_t bno;
        int cg;
#ifdef QUOTA
        int error;
#endif

        *bnp = 0;
        fs = ip->i_fs;
#ifdef DIAGNOSTIC
        if ((uint)size > fs->fs_bsize || fragoff(fs, size) != 0) {
                kprintf("dev = %s, bsize = %ld, size = %d, fs = %s\n",
                    devtoname(ip->i_dev), (long)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) - numfrags(fs, size) < 0)
                goto nospace;
#ifdef QUOTA
        error = ufs_chkdq(ip, (long)btodb(size), cred, 0);
        if (error)
                return (error);
#endif
        if (bpref >= fs->fs_size)
                bpref = 0;
        if (bpref == 0)
                cg = ino_to_cg(fs, ip->i_number);
        else
                cg = dtog(fs, bpref);
        bno = (ufs_daddr_t)ffs_hashalloc(ip, cg, (long)bpref, size,
                                         ffs_alloccg);
        if (bno > 0) {
                ip->i_blocks += btodb(size);
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
                *bnp = bno;
                return (0);
        }
#ifdef QUOTA
        /*
         * Restore user's disk quota because allocation failed.
         */
        (void) ufs_chkdq(ip, (long)-btodb(size), cred, FORCE);
#endif
nospace:
        ffs_fserr(fs, cred->cr_uid, "filesystem full");
        uprintf("\n%s: write failed, filesystem 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, ufs_daddr_t lbprev, ufs_daddr_t bpref,
              int osize, int nsize, struct ucred *cred, struct buf **bpp)
{
        struct fs *fs;
        struct buf *bp;
        int cg, request, error;
        ufs_daddr_t bprev, bno;

        *bpp = NULL;
        fs = ip->i_fs;
#ifdef DIAGNOSTIC
        if ((uint)osize > fs->fs_bsize || fragoff(fs, osize) != 0 ||
            (uint)nsize > fs->fs_bsize || fragoff(fs, nsize) != 0) {
                kprintf(
                "dev = %s, bsize = %ld, osize = %d, nsize = %d, fs = %s\n",
                    devtoname(ip->i_dev), (long)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) -  numfrags(fs, nsize - osize) < 0)
                goto nospace;
        if ((bprev = ip->i_db[lbprev]) == 0) {
                kprintf("dev = %s, bsize = %ld, bprev = %ld, fs = %s\n",
                    devtoname(ip->i_dev), (long)fs->fs_bsize, (long)bprev,
                    fs->fs_fsmnt);
                panic("ffs_realloccg: bad bprev");
        }
        /*
         * Allocate the extra space in the buffer.
         */
        error = bread(ITOV(ip), lblktodoff(fs, lbprev), osize, &bp);
        if (error) {
                brelse(bp);
                return (error);
        }

        if(bp->b_bio2.bio_offset == NOOFFSET) {
                if (lbprev >= UFS_NDADDR)
                        panic("ffs_realloccg: lbprev out of range");
                bp->b_bio2.bio_offset = fsbtodoff(fs, bprev);
        }

#ifdef QUOTA
        error = ufs_chkdq(ip, (long)btodb(nsize - osize), cred, 0);
        if (error) {
                brelse(bp);
                return (error);
        }
#endif
        /*
         * Check for extension in the existing location.
         */
        cg = dtog(fs, bprev);
        bno = ffs_fragextend(ip, cg, (long)bprev, osize, nsize);
        if (bno) {
                if (bp->b_bio2.bio_offset != fsbtodoff(fs, bno))
                        panic("ffs_realloccg: bad blockno");
                ip->i_blocks += btodb(nsize - osize);
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
                allocbuf(bp, nsize);
                bzero((char *)bp->b_data + osize, (uint)nsize - osize);
                *bpp = bp;
                return (0);
        }
        /*
         * Allocate a new disk location.
         */
        if (bpref >= fs->fs_size)
                bpref = 0;
        switch ((int)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 >
                    (off_t)fs->fs_dsize * fs->fs_minfree / (2 * 100))
                        break;
                log(LOG_NOTICE, "%s: optimization changed from SPACE to TIME\n",
                        fs->fs_fsmnt);
                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 <
                    (off_t)fs->fs_dsize * (fs->fs_minfree - 2) / 100)
                        break;
                log(LOG_NOTICE, "%s: optimization changed from TIME to SPACE\n",
                        fs->fs_fsmnt);
                fs->fs_optim = FS_OPTSPACE;
                break;
        default:
                kprintf("dev = %s, optim = %ld, fs = %s\n",
                    devtoname(ip->i_dev), (long)fs->fs_optim, fs->fs_fsmnt);
                panic("ffs_realloccg: bad optim");
                /* NOTREACHED */
        }
        bno = (ufs_daddr_t)ffs_hashalloc(ip, cg, (long)bpref, request,
                                         ffs_alloccg);
        if (bno > 0) {
                bp->b_bio2.bio_offset = fsbtodoff(fs, bno);
                if (!DOINGSOFTDEP(ITOV(ip)))
                        ffs_blkfree(ip, bprev, (long)osize);
                if (nsize < request)
                        ffs_blkfree(ip, bno + numfrags(fs, nsize),
                            (long)(request - nsize));
                ip->i_blocks += btodb(nsize - osize);
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
                allocbuf(bp, nsize);
                bzero((char *)bp->b_data + osize, (uint)nsize - osize);
                *bpp = bp;
                return (0);
        }
#ifdef QUOTA
        /*
         * Restore user's disk quota because allocation failed.
         */
        (void) ufs_chkdq(ip, (long)-btodb(nsize - osize), cred, FORCE);
#endif
        brelse(bp);
nospace:
        /*
         * no space available
         */
        ffs_fserr(fs, cred->cr_uid, "filesystem full");
        uprintf("\n%s: write failed, filesystem is full\n", fs->fs_fsmnt);
        return (ENOSPC);
}

SYSCTL_NODE(_vfs, OID_AUTO, ffs, CTLFLAG_RW, 0, "FFS filesystem");

/*
 * Reallocate a sequence of blocks into a contiguous sequence of blocks.
 *
 * The vnode and an array of buffer pointers for a range of sequential
 * logical blocks to be made contiguous is given. The allocator attempts
 * to find a range of sequential blocks starting as close as possible to
 * an fs_rotdelay offset from the end of the allocation for the logical
 * block immediately preceeding the current range. If successful, the
 * physical block numbers in the buffer pointers and in the inode are
 * changed to reflect the new allocation. If unsuccessful, the allocation
 * is left unchanged. The success in doing the reallocation is returned.
 * Note that the error return is not reflected back to the user. Rather
 * the previous block allocation will be used.
 */
static int doasyncfree = 1;
SYSCTL_INT(_vfs_ffs, FFS_ASYNCFREE, doasyncfree, CTLFLAG_RW, &doasyncfree, 0, "");

static int doreallocblks = 1;
SYSCTL_INT(_vfs_ffs, FFS_REALLOCBLKS, doreallocblks, CTLFLAG_RW, &doreallocblks, 0, "");

#ifdef DEBUG
static volatile int prtrealloc = 0;
#endif

/*
 * ffs_reallocblks(struct vnode *a_vp, struct cluster_save *a_buflist)
 */
int
ffs_reallocblks(struct vop_reallocblks_args *ap)
{
        struct fs *fs;
        struct inode *ip;
        struct vnode *vp;
        struct buf *sbp, *ebp;
        ufs_daddr_t *bap, *sbap, *ebap = NULL;
        struct cluster_save *buflist;
        ufs_daddr_t start_lbn, end_lbn, soff, newblk, blkno;
#ifdef DIAGNOSTIC
        off_t boffset;
#endif
        struct indir start_ap[UFS_NIADDR + 1], end_ap[UFS_NIADDR + 1], *idp;
        int i, len, slen, start_lvl, end_lvl, pref, ssize;

        if (doreallocblks == 0)
                return (ENOSPC);
        vp = ap->a_vp;
        ip = VTOI(vp);
        fs = ip->i_fs;
        if (fs->fs_contigsumsize <= 0)
                return (ENOSPC);
        buflist = ap->a_buflist;
        len = buflist->bs_nchildren;
        start_lbn = lblkno(fs, buflist->bs_children[0]->b_loffset);
        end_lbn = start_lbn + len - 1;
#ifdef DIAGNOSTIC
        for (i = 0; i < len; i++)
                if (!ffs_checkblk(ip,
                   dofftofsb(fs, buflist->bs_children[i]->b_bio2.bio_offset), fs->fs_bsize))
                        panic("ffs_reallocblks: unallocated block 1");
        for (i = 1; i < len; i++) {
                if (buflist->bs_children[i]->b_loffset != lblktodoff(fs, start_lbn) + lblktodoff(fs, i))
                        panic("ffs_reallocblks: non-logical cluster");
        }
        boffset = buflist->bs_children[0]->b_bio2.bio_offset;
        ssize = (int)fsbtodoff(fs, fs->fs_frag);
        for (i = 1; i < len - 1; i++)
                if (buflist->bs_children[i]->b_bio2.bio_offset != boffset + (i * ssize))
                        panic("ffs_reallocblks: non-physical cluster %d", i);
#endif
        /*
         * If the latest allocation is in a new cylinder group, assume that
         * the filesystem has decided to move and do not force it back to
         * the previous cylinder group.
         */
        if (dtog(fs, dofftofsb(fs, buflist->bs_children[0]->b_bio2.bio_offset)) !=
            dtog(fs, dofftofsb(fs, buflist->bs_children[len - 1]->b_bio2.bio_offset)))
                return (ENOSPC);
        if (ufs_getlbns(vp, start_lbn, start_ap, &start_lvl) ||
            ufs_getlbns(vp, end_lbn, end_ap, &end_lvl))
                return (ENOSPC);
        /*
         * Get the starting offset and block map for the first block and
         * the number of blocks that will fit into sbap starting at soff.
         */
        if (start_lvl == 0) {
                sbap = &ip->i_db[0];
                soff = start_lbn;
                slen = UFS_NDADDR - soff;
        } else {
                idp = &start_ap[start_lvl - 1];
                if (bread(vp, lblktodoff(fs, idp->in_lbn), (int)fs->fs_bsize, &sbp)) {
                        brelse(sbp);
                        return (ENOSPC);
                }
                sbap = (ufs_daddr_t *)sbp->b_data;
                soff = idp->in_off;
                slen = fs->fs_nindir - soff;
        }
        /*
         * Find the preferred location for the cluster.
         */
        pref = ffs_blkpref(ip, start_lbn, soff, sbap);

        /*
         * If the block range spans two block maps, get the second map.
         */
        if (end_lvl == 0 || (idp = &end_ap[end_lvl - 1])->in_off + 1 >= len) {
                ssize = len;
        } else {
#ifdef DIAGNOSTIC
                if (start_ap[start_lvl-1].in_lbn == idp->in_lbn)
                        panic("ffs_reallocblk: start == end");
#endif
                ssize = len - (idp->in_off + 1);
                if (bread(vp, lblktodoff(fs, idp->in_lbn), (int)fs->fs_bsize, &ebp))
                        goto fail;
                ebap = (ufs_daddr_t *)ebp->b_data;
        }

        /*
         * Make sure we aren't spanning more then two blockmaps.  ssize is
         * our calculation of the span we have to scan in the first blockmap,
         * while slen is our calculation of the number of entries available
         * in the first blockmap (from soff).
         */
        if (ssize > slen) {
                panic("ffs_reallocblks: range spans more than two blockmaps!"
                        " start_lbn %ld len %d (%d/%d)",
                        (long)start_lbn, len, slen, ssize);
        }
        /*
         * Search the block map looking for an allocation of the desired size.
         */
        if ((newblk = (ufs_daddr_t)ffs_hashalloc(ip, dtog(fs, pref), (long)pref,
            len, ffs_clusteralloc)) == 0)
                goto fail;
        /*
         * We have found a new contiguous block.
         *
         * First we have to replace the old block pointers with the new
         * block pointers in the inode and indirect blocks associated
         * with the file.
         */
#ifdef DEBUG
        if (prtrealloc)
                kprintf("realloc: ino %ju, lbns %d-%d\n\told:",
                    (uintmax_t)ip->i_number, start_lbn, end_lbn);
#endif
        blkno = newblk;
        for (bap = &sbap[soff], i = 0; i < len; i++, blkno += fs->fs_frag) {
                if (i == ssize) {
                        bap = ebap;
                        soff = -i;
                }
#ifdef DIAGNOSTIC
                if (!ffs_checkblk(ip,
                   dofftofsb(fs, buflist->bs_children[i]->b_bio2.bio_offset), fs->fs_bsize))
                        panic("ffs_reallocblks: unallocated block 2");
                if (dofftofsb(fs, buflist->bs_children[i]->b_bio2.bio_offset) != *bap)
                        panic("ffs_reallocblks: alloc mismatch");
#endif
#ifdef DEBUG
                if (prtrealloc)
                        kprintf(" %d,", *bap);
#endif
                if (DOINGSOFTDEP(vp)) {
                        if (sbap == &ip->i_db[0] && i < ssize)
                                softdep_setup_allocdirect(ip, start_lbn + i,
                                    blkno, *bap, fs->fs_bsize, fs->fs_bsize,
                                    buflist->bs_children[i]);
                        else
                                softdep_setup_allocindir_page(ip, start_lbn + i,
                                    i < ssize ? sbp : ebp, soff + i, blkno,
                                    *bap, buflist->bs_children[i]);
                }
                *bap++ = blkno;
        }
        /*
         * Next we must write out the modified inode and indirect blocks.
         * For strict correctness, the writes should be synchronous since
         * the old block values may have been written to disk. In practise
         * they are almost never written, but if we are concerned about
         * strict correctness, the `doasyncfree' flag should be set to zero.
         *
         * The test on `doasyncfree' should be changed to test a flag
         * that shows whether the associated buffers and inodes have
         * been written. The flag should be set when the cluster is
         * started and cleared whenever the buffer or inode is flushed.
         * We can then check below to see if it is set, and do the
         * synchronous write only when it has been cleared.
         */
        if (sbap != &ip->i_db[0]) {
                if (doasyncfree)
                        bdwrite(sbp);
                else
                        bwrite(sbp);
        } else {
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
                if (!doasyncfree)
                        ffs_update(vp, 1);
        }
        if (ssize < len) {
                if (doasyncfree)
                        bdwrite(ebp);
                else
                        bwrite(ebp);
        }
        /*
         * Last, free the old blocks and assign the new blocks to the buffers.
         */
#ifdef DEBUG
        if (prtrealloc)
                kprintf("\n\tnew:");
#endif
        for (blkno = newblk, i = 0; i < len; i++, blkno += fs->fs_frag) {
                if (!DOINGSOFTDEP(vp) &&
                    buflist->bs_children[i]->b_bio2.bio_offset != NOOFFSET) {
                        ffs_blkfree(ip,
                            dofftofsb(fs, buflist->bs_children[i]->b_bio2.bio_offset),
                            fs->fs_bsize);
                }
                buflist->bs_children[i]->b_bio2.bio_offset = fsbtodoff(fs, blkno);
#ifdef DIAGNOSTIC
                if (!ffs_checkblk(ip,
                   dofftofsb(fs, buflist->bs_children[i]->b_bio2.bio_offset), fs->fs_bsize))
                        panic("ffs_reallocblks: unallocated block 3");
#endif
#ifdef DEBUG
                if (prtrealloc)
                        kprintf(" %d,", blkno);
#endif
        }
#ifdef DEBUG
        if (prtrealloc) {
                prtrealloc--;
                kprintf("\n");
        }
#endif
        return (0);

fail:
        if (ssize < len)
                brelse(ebp);
        if (sbap != &ip->i_db[0])
                brelse(sbp);
        return (ENOSPC);
}

/*
 * Allocate an inode in the filesystem.
 *
 * 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) quadradically rehash into other cylinder groups, until an
 *      available inode is located.
 * If no inode preference is given the following heirarchy is used
 * to allocate an inode:
 *   1) allocate an inode in cylinder group 0.
 *   2) quadradically rehash into other cylinder groups, until an
 *      available inode is located.
 */
int
ffs_valloc(struct vnode *pvp, int mode, struct ucred *cred, struct vnode **vpp)
{
        struct inode *pip;
        struct fs *fs;
        struct inode *ip;
        ino_t ino, ipref;
        int cg, error;

        *vpp = NULL;
        pip = VTOI(pvp);
        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 = (ino_t)ffs_hashalloc(pip, cg, (long)ipref, mode,
                                        (allocfcn_t *)ffs_nodealloccg);
        if (ino == 0)
                goto noinodes;
        error = VFS_VGET(pvp->v_mount, NULL, ino, vpp);
        if (error) {
                ffs_vfree(pvp, ino, mode);
                return (error);
        }
        ip = VTOI(*vpp);
        if (ip->i_mode) {
                kprintf("mode = 0%o, inum = %lu, fs = %s\n",
                    ip->i_mode, (u_long)ip->i_number, fs->fs_fsmnt);
                panic("ffs_valloc: dup alloc");
        }
        if (ip->i_blocks) {                             /* XXX */
                kprintf("free inode %s/%lu had %ld blocks\n",
                    fs->fs_fsmnt, (u_long)ino, (long)ip->i_blocks);
                ip->i_blocks = 0;
        }
        ip->i_flags = 0;
        /*
         * Set up a new generation number for this inode.
         */
        if (ip->i_gen == 0 || ++ip->i_gen == 0)
                ip->i_gen = krandom() / 2 + 1;
        return (0);
noinodes:
        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.
 */
static ino_t
ffs_dirpref(struct inode *pip)
{
        struct fs *fs;
        int cg, prefcg, dirsize, cgsize;
        int64_t dirsize64;
        int avgifree, avgbfree, avgndir, curdirsize;
        int minifree, minbfree, maxndir;
        int mincg, minndir;
        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 = karc4random() % 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;
                        }
                return ((ino_t)(fs->fs_ipg * mincg));
        }

        /*
         * 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;

        /*
         * fs_avgfilesize and fs_avgfpdir are user-settable entities and
         * multiplying them may overflow a 32 bit integer.
         */
        dirsize64 = fs->fs_avgfilesize * (int64_t)fs->fs_avgfpdir;
        if (dirsize64 > 0x7fffffff) {
                maxcontigdirs = 1;
        } else {
                dirsize = (int)dirsize64;
                curdirsize = avgndir ?
                        (cgsize - avgbfree * fs->fs_bsize) / avgndir : 0;
                if (dirsize < curdirsize)
                        dirsize = curdirsize;
                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.
         */
        prefcg = ino_to_cg(fs, pip->i_number);
        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)
                                return ((ino_t)(fs->fs_ipg * cg));
                }
        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)
                                return ((ino_t)(fs->fs_ipg * cg));
                }
        /*
         * 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)
                        return ((ino_t)(fs->fs_ipg * cg));
        for (cg = 0; cg < prefcg; cg++)
                if (fs->fs_cs(fs, cg).cs_nifree >= avgifree)
                        break;
        return ((ino_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. If no blocks have been allocated in any other section, the
 * policy is to place the section 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.
 *
 * If a section is already partially allocated, the policy is to
 * contiguously allocate fs_maxcontig blocks.  The end of one of these
 * contiguous blocks and the beginning of the next is physically separated
 * so that the disk head will be in transit between them for at least
 * fs_rotdelay milliseconds.  This is to allow time for the processor to
 * schedule another I/O transfer.
 */
ufs_daddr_t
ffs_blkpref(struct inode *ip, ufs_daddr_t lbn, int indx, ufs_daddr_t *bap)
{
        struct fs *fs;
        int cg;
        int avgbfree, startcg;
        ufs_daddr_t nextblk;

        fs = ip->i_fs;
        if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) {
                if (lbn < UFS_NDADDR + NINDIR(fs)) {
                        cg = ino_to_cg(fs, ip->i_number);
                        return (fs->fs_fpg * cg + fs->fs_frag);
                }
                /*
                 * Find a cylinder with greater than average number of
                 * unused data blocks.
                 */
                if (indx == 0 || bap[indx - 1] == 0)
                        startcg =
                            ino_to_cg(fs, ip->i_number) + 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 (fs->fs_fpg * cg + fs->fs_frag);
                        }
                for (cg = 0; cg <= startcg; cg++)
                        if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
                                fs->fs_cgrotor = cg;
                                return (fs->fs_fpg * cg + fs->fs_frag);
                        }
                return (0);
        }
        /*
         * One or more previous blocks have been laid out. If less
         * than fs_maxcontig previous blocks are contiguous, the
         * next block is requested contiguously, otherwise it is
         * requested rotationally delayed by fs_rotdelay milliseconds.
         */
        nextblk = bap[indx - 1] + fs->fs_frag;
        if (fs->fs_rotdelay == 0 || indx < fs->fs_maxcontig ||
            bap[indx - fs->fs_maxcontig] +
            blkstofrags(fs, fs->fs_maxcontig) != nextblk)
                return (nextblk);
        /*
         * Here we convert ms of delay to frags as:
         * (frags) = (ms) * (rev/sec) * (sect/rev) /
         *      ((sect/frag) * (ms/sec))
         * then round up to the next block.
         */
        nextblk += roundup(fs->fs_rotdelay * fs->fs_rps * fs->fs_nsect /
            (NSPF(fs) * 1000), fs->fs_frag);
        return (nextblk);
}

/*
 * Implement the cylinder overflow algorithm.
 *
 * The policy implemented by this algorithm is:
 *   1) allocate the block in its requested cylinder group.
 *   2) quadradically rehash on the cylinder group number.
 *   3) brute force search for a free block.
 */
/*VARARGS5*/
static u_long
ffs_hashalloc(struct inode *ip, int cg, long pref,
              int size, /* size for data blocks, mode for inodes */
              allocfcn_t *allocator)
{
        struct fs *fs;
        long result;    /* XXX why not same type as we return? */
        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);
}

/*
 * Determine whether a fragment can be extended.
 *
 * Check to see if the necessary fragments are available, and
 * if they are, allocate them.
 */
static ufs_daddr_t
ffs_fragextend(struct inode *ip, int cg, long bprev, int osize, int nsize)
{
        struct fs *fs;
        struct cg *cgp;
        struct buf *bp;
        long bno;
        int frags, bbase;
        int i, error;
        uint8_t *blksfree;

        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);
        }
        KKASSERT(blknum(fs, bprev) == blknum(fs, bprev + frags - 1));
        error = bread(ip->i_devvp, fsbtodoff(fs, cgtod(fs, cg)),
                (int)fs->fs_cgsize, &bp);
        if (error) {
                brelse(bp);
                return (0);
        }
        cgp = (struct cg *)bp->b_data;
        if (!cg_chkmagic(cgp)) {
                brelse(bp);
                return (0);
        }
        cgp->cg_time = time_second;
        bno = dtogd(fs, bprev);
        blksfree = cg_blksfree(cgp);
        for (i = numfrags(fs, osize); i < frags; i++) {
                if (isclr(blksfree, 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
         *
         * ---oooooooooonnnnnnn111----
         *    [-----frags-----]
         *    ^                       ^
         *    bbase                   fs_frag
         */
        for (i = frags; i < fs->fs_frag - bbase; i++) {
                if (isclr(blksfree, bno + i))
                        break;
        }

        /*
         * Size of original free frag is [i - numfrags(fs, osize)]
         * Size of remaining free frag is [i - frags]
         */
        cgp->cg_frsum[i - numfrags(fs, osize)]--;
        if (i != frags)
                cgp->cg_frsum[i - frags]++;
        for (i = numfrags(fs, osize); i < frags; i++) {
                clrbit(blksfree, bno + i);
                cgp->cg_cs.cs_nffree--;
                fs->fs_cstotal.cs_nffree--;
                fs->fs_cs(fs, cg).cs_nffree--;
        }
        fs->fs_fmod = 1;
        if (DOINGSOFTDEP(ITOV(ip)))
                softdep_setup_blkmapdep(bp, fs, bprev);
        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.
 */
static ufs_daddr_t
ffs_alloccg(struct inode *ip, int cg, ufs_daddr_t bpref, int size)
{
        struct fs *fs;
        struct cg *cgp;
        struct buf *bp;
        int i;
        ufs_daddr_t bno, blkno;
        int allocsiz, error, frags;
        uint8_t *blksfree;

        fs = ip->i_fs;
        if (fs->fs_cs(fs, cg).cs_nbfree == 0 && size == fs->fs_bsize)
                return (0);
        error = bread(ip->i_devvp, fsbtodoff(fs, cgtod(fs, cg)),
                (int)fs->fs_cgsize, &bp);
        if (error) {
                brelse(bp);
                return (0);
        }
        cgp = (struct cg *)bp->b_data;
        if (!cg_chkmagic(cgp) ||
            (cgp->cg_cs.cs_nbfree == 0 && size == fs->fs_bsize)) {
                brelse(bp);
                return (0);
        }
        cgp->cg_time = time_second;
        if (size == fs->fs_bsize) {
                bno = ffs_alloccgblk(ip, bp, bpref);
                bdwrite(bp);
                return (bno);
        }
        /*
         * Check to see if any fragments of sufficient size are already
         * available.  Fit the data into a larger fragment if necessary,
         * before allocating a whole new block.
         */
        blksfree = cg_blksfree(cgp);
        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, allocate a whole block and
                 * cut the requested fragment (of size frags) out of it.
                 */
                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(blksfree, bpref + i);

                /*
                 * Calculate the number of free frags still remaining after
                 * we have cut out the requested allocation.  Indicate that
                 * a fragment of that size is now available for future
                 * allocation.
                 */
                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);
        }

        /*
         * cg_frsum[] has told us that a free fragment of allocsiz size is
         * available.  Find it, then clear the bitmap bits associated with
         * the size we want.
         */
        bno = ffs_mapsearch(fs, cgp, bpref, allocsiz);
        if (bno < 0) {
                brelse(bp);
                return (0);
        }
        for (i = 0; i < frags; i++)
                clrbit(blksfree, 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;

        /*
         * Account for the allocation.  The original searched size that we
         * found is no longer available.  If we cut out a smaller piece then
         * a smaller fragment is now available.
         */
        cgp->cg_frsum[allocsiz]--;
        if (frags != allocsiz)
                cgp->cg_frsum[allocsiz - frags]++;
        blkno = cg * fs->fs_fpg + bno;
        if (DOINGSOFTDEP(ITOV(ip)))
                softdep_setup_blkmapdep(bp, fs, blkno);
        bdwrite(bp);
        return ((u_long)blkno);
}

/*
 * Allocate a block in a cylinder group.
 *
 * This algorithm implements the following policy:
 *   1) allocate the requested block.
 *   2) allocate a rotationally optimal block in the same cylinder.
 *   3) allocate the next available block on the block rotor for the
 *      specified cylinder group.
 * Note that this routine only allocates fs_bsize blocks; these
 * blocks may be fragmented by the routine that allocates them.
 */
static ufs_daddr_t
ffs_alloccgblk(struct inode *ip, struct buf *bp, ufs_daddr_t bpref)
{
        struct fs *fs;
        struct cg *cgp;
        ufs_daddr_t bno, blkno;
        int cylno, pos, delta;
        short *cylbp;
        int i;
        uint8_t *blksfree;

        fs = ip->i_fs;
        cgp = (struct cg *)bp->b_data;
        blksfree = cg_blksfree(cgp);
        if (bpref == 0 || dtog(fs, bpref) != cgp->cg_cgx) {
                bpref = cgp->cg_rotor;
                goto norot;
        }
        bpref = blknum(fs, bpref);
        bpref = dtogd(fs, bpref);
        /*
         * if the requested block is available, use it
         */
        if (ffs_isblock(fs, blksfree, fragstoblks(fs, bpref))) {
                bno = bpref;
                goto gotit;
        }
        if (fs->fs_nrpos <= 1 || fs->fs_cpc == 0) {
                /*
                 * Block layout information is not available.
                 * Leaving bpref unchanged means we take the
                 * next available free block following the one
                 * we just allocated. Hopefully this will at
                 * least hit a track cache on drives of unknown
                 * geometry (e.g. SCSI).
                 */
                goto norot;
        }
        /*
         * check for a block available on the same cylinder
         */
        cylno = cbtocylno(fs, bpref);
        if (cg_blktot(cgp)[cylno] == 0)
                goto norot;
        /*
         * check the summary information to see if a block is
         * available in the requested cylinder starting at the
         * requested rotational position and proceeding around.
         */
        cylbp = cg_blks(fs, cgp, cylno);
        pos = cbtorpos(fs, bpref);
        for (i = pos; i < fs->fs_nrpos; i++)
                if (cylbp[i] > 0)
                        break;
        if (i == fs->fs_nrpos)
                for (i = 0; i < pos; i++)
                        if (cylbp[i] > 0)
                                break;
        if (cylbp[i] > 0) {
                /*
                 * found a rotational position, now find the actual
                 * block. A panic if none is actually there.
                 */
                pos = cylno % fs->fs_cpc;
                bno = (cylno - pos) * fs->fs_spc / NSPB(fs);
                if (fs_postbl(fs, pos)[i] == -1) {
                        kprintf("pos = %d, i = %d, fs = %s\n",
                            pos, i, fs->fs_fsmnt);
                        panic("ffs_alloccgblk: cyl groups corrupted");
                }
                for (i = fs_postbl(fs, pos)[i];; ) {
                        if (ffs_isblock(fs, blksfree, bno + i)) {
                                bno = blkstofrags(fs, (bno + i));
                                goto gotit;
                        }
                        delta = fs_rotbl(fs)[i];
                        if (delta <= 0 ||
                            delta + i > fragstoblks(fs, fs->fs_fpg))
                                break;
                        i += delta;
                }
                kprintf("pos = %d, i = %d, fs = %s\n", pos, i, fs->fs_fsmnt);
                panic("ffs_alloccgblk: can't find blk in cyl");
        }
norot:
        /*
         * no blocks in the requested cylinder, so take next
         * available one in this cylinder group.
         */
        bno = ffs_mapsearch(fs, cgp, bpref, (int)fs->fs_frag);
        if (bno < 0)
                return (0);
        cgp->cg_rotor = bno;
gotit:
        blkno = fragstoblks(fs, bno);
        ffs_clrblock(fs, blksfree, (long)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--;
        cylno = cbtocylno(fs, bno);
        cg_blks(fs, cgp, cylno)[cbtorpos(fs, bno)]--;
        cg_blktot(cgp)[cylno]--;
        fs->fs_fmod = 1;
        blkno = cgp->cg_cgx * fs->fs_fpg + bno;
        if (DOINGSOFTDEP(ITOV(ip)))
                softdep_setup_blkmapdep(bp, fs, blkno);
        return (blkno);
}

/*
 * Determine whether a cluster can be allocated.
 *
 * We do not currently check for optimal rotational layout if there
 * are multiple choices in the same cylinder group. Instead we just
 * take the first one that we find following bpref.
 */
static ufs_daddr_t
ffs_clusteralloc(struct inode *ip, int cg, ufs_daddr_t bpref, int len)
{
        struct fs *fs;
        struct cg *cgp;
        struct buf *bp;
        int i, got, run, bno, bit, map;
        u_char *mapp;
        int32_t *lp;
        uint8_t *blksfree;

        fs = ip->i_fs;
        if (fs->fs_maxcluster[cg] < len)
                return (0);
        if (bread(ip->i_devvp, fsbtodoff(fs, cgtod(fs, cg)),
                  (int)fs->fs_cgsize, &bp)) {
                goto fail;
        }
        cgp = (struct cg *)bp->b_data;
        if (!cg_chkmagic(cgp))
                goto fail;

        /*
         * Check to see if a cluster of the needed size (or bigger) is
         * available in this cylinder group.
         */
        lp = &cg_clustersum(cgp)[len];
        for (i = len; i <= fs->fs_contigsumsize; i++)
                if (*lp++ > 0)
                        break;
        if (i > fs->fs_contigsumsize) {
                /*
                 * This is the first time looking for a cluster in this
                 * cylinder group. Update the cluster summary information
                 * to reflect the true maximum sized cluster so that
                 * future cluster allocation requests can avoid reading
                 * the cylinder group map only to find no clusters.
                 */
                lp = &cg_clustersum(cgp)[len - 1];
                for (i = len - 1; i > 0; i--)
                        if (*lp-- > 0)
                                break;
                fs->fs_maxcluster[cg] = i;
                goto fail;
        }
        /*
         * Search the cluster map to find a big enough cluster.
         * We take the first one that we find, even if it is larger
         * than we need as we prefer to get one close to the previous
         * block allocation. We do not search before the current
         * preference point as we do not want to allocate a block
         * that is allocated before the previous one (as we will
         * then have to wait for another pass of the elevator
         * algorithm before it will be read). We prefer to fail and
         * be recalled to try an allocation in the next cylinder group.
         */
        if (dtog(fs, bpref) != cg)
                bpref = 0;
        else
                bpref = fragstoblks(fs, dtogd(fs, blknum(fs, bpref)));
        mapp = &cg_clustersfree(cgp)[bpref / NBBY];
        map = *mapp++;
        bit = 1 << (bpref % NBBY);
        for (run = 0, got = bpref; got < cgp->cg_nclusterblks; got++) {
                if ((map & bit) == 0) {
                        run = 0;
                } else {
                        run++;
                        if (run == len)
                                break;
                }
                if ((got & (NBBY - 1)) != (NBBY - 1)) {
                        bit <<= 1;
                } else {
                        map = *mapp++;
                        bit = 1;
                }
        }
        if (got >= cgp->cg_nclusterblks)
                goto fail;
        /*
         * Allocate the cluster that we have found.
         */
        blksfree = cg_blksfree(cgp);
        for (i = 1; i <= len; i++) {
                if (!ffs_isblock(fs, blksfree, got - run + i))
                        panic("ffs_clusteralloc: map mismatch");
        }
        bno = cg * fs->fs_fpg + blkstofrags(fs, got - run + 1);
        if (dtog(fs, bno) != cg)
                panic("ffs_clusteralloc: allocated out of group");
        len = blkstofrags(fs, len);
        for (i = 0; i < len; i += fs->fs_frag) {
                if ((got = ffs_alloccgblk(ip, bp, bno + i)) != bno + i)
                        panic("ffs_clusteralloc: lost block");
        }
        bdwrite(bp);
        return (bno);

fail:
        brelse(bp);
        return (0);
}

/*
 * Determine whether an inode can be allocated.
 *
 * Check to see if an inode is available, and if it is,
 * allocate it using the following policy:
 *   1) allocate the requested inode.
 *   2) allocate the next available inode after the requested
 *      inode in the specified cylinder group.
 *   3) the inode must not already be in the inode hash table.  We
 *      can encounter such a case because the vnode reclamation sequence
 *      frees the bit
 *   3) the inode must not already be in the inode hash, otherwise it
 *      may be in the process of being deallocated.  This can occur
 *      because the bitmap is updated before the inode is removed from
 *      hash.  If we were to reallocate the inode the caller could wind
 *      up returning a vnode/inode combination which is in an indeterminate
 *      state.
 */
static ino_t
ffs_nodealloccg(struct inode *ip, int cg, ufs_daddr_t ipref, int mode)
{
        struct ufsmount *ump;
        struct fs *fs;
        struct cg *cgp;
        struct buf *bp;
        uint8_t *inosused;
        uint8_t map;
        int error, len, arraysize, i;
        int icheckmiss;
        ufs_daddr_t ibase;
        struct vnode *vp;

        vp = ITOV(ip);
        ump = VFSTOUFS(vp->v_mount);
        fs = ip->i_fs;
        if (fs->fs_cs(fs, cg).cs_nifree == 0)
                return (0);
        error = bread(ip->i_devvp, fsbtodoff(fs, cgtod(fs, cg)),
                      (int)fs->fs_cgsize, &bp);
        if (error) {
                brelse(bp);
                return (0);
        }
        cgp = (struct cg *)bp->b_data;
        if (!cg_chkmagic(cgp) || cgp->cg_cs.cs_nifree == 0) {
                brelse(bp);
                return (0);
        }
        inosused = cg_inosused(cgp);
        icheckmiss = 0;

        /*
         * Quick check, reuse the most recently free inode or continue
         * a scan from where we left off the last time.
         */
        ibase = cg * fs->fs_ipg;
        if (ipref) {
                ipref %= fs->fs_ipg;
                if (isclr(inosused, ipref)) {
                        if (ufs_ihashcheck(ump, ip->i_dev, ibase + ipref) == 0)
                                goto gotit;
                }
        }

        /*
         * Scan the inode bitmap starting at irotor, be sure to handle
         * the edge case by going back to the beginning of the array.
         *
         * If the number of inodes is not byte-aligned, the unused bits
         * should be set to 1.  This will be sanity checked in gotit.  Note
         * that we have to be sure not to overlap the beginning and end
         * when irotor is in the middle of a byte as this will cause the
         * same bitmap byte to be checked twice.  To solve this problem we
         * just convert everything to a byte index for the loop.
         */
        ipref = (cgp->cg_irotor % fs->fs_ipg) >> 3;     /* byte index */
        len = (fs->fs_ipg + 7) >> 3;                    /* byte size */
        arraysize = len;

        while (len > 0) {
                map = inosused[ipref];
                if (map != 255) {
                        for (i = 0; i < NBBY; ++i) {
                                /*
                                 * If we find a free bit we have to make sure
                                 * that the inode is not in the middle of
                                 * being destroyed.  The inode should not exist
                                 * in the inode hash.
                                 *
                                 * Adjust the rotor to try to hit the 
                                 * quick-check up above.
                                 */
                                if ((map & (1 << i)) == 0) {
                                        if (ufs_ihashcheck(ump, ip->i_dev, ibase + (ipref << 3) + i) == 0) {
                                                ipref = (ipref << 3) + i;
                                                cgp->cg_irotor = (ipref + 1) % fs->fs_ipg;
                                                goto gotit;
                                        }
                                        ++icheckmiss;
                                }
                        }
                }

                /*
                 * Setup for the next byte, start at the beginning again if
                 * we hit the end of the array.
                 */
                if (++ipref == arraysize)
                        ipref = 0;
                --len;
        }
        if (icheckmiss == cgp->cg_cs.cs_nifree) {
                brelse(bp);
                return(0);
        }
        kprintf("fs = %s\n", fs->fs_fsmnt);
        panic("ffs_nodealloccg: block not in map, icheckmiss/nfree %d/%d",
                icheckmiss, cgp->cg_cs.cs_nifree);
        /* NOTREACHED */

        /*
         * ipref is a bit index as of the gotit label.
         */
gotit:
        KKASSERT(ipref >= 0 && ipref < fs->fs_ipg);
        cgp->cg_time = time_second;
        if (DOINGSOFTDEP(ITOV(ip)))
                softdep_setup_inomapdep(bp, ip, ibase + ipref);
        setbit(inosused, ipref);
        cgp->cg_cs.cs_nifree--;
        fs->fs_cstotal.cs_nifree--;
        fs->fs_cs(fs, cg).cs_nifree--;
        fs->fs_fmod = 1;
        if ((mode & IFMT) == IFDIR) {
                cgp->cg_cs.cs_ndir++;
                fs->fs_cstotal.cs_ndir++;
                fs->fs_cs(fs, cg).cs_ndir++;
        }
        bdwrite(bp);
        return (ibase + 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_cg(struct fs * fs, struct vnode * i_devvp, cdev_t i_dev, ino_t i_number,
                uint32_t i_din_uid, ufs_daddr_t bno, long size)
{
        struct cg *cgp;
        struct buf *bp;
        ufs_daddr_t blkno;
        int i, error, cg, blk, frags, bbase;
        uint8_t *blksfree;

#if 0
        /*
         * ffs_blkfree() handles TRIM if UFS is mounted with the 'trim'
         * option, do not issue an unconditional duplicate here!
         * VOP_FREEBLKS(i_devvp, fsbtodoff(fs, bno), size);
         */
#endif
        if ((uint)size > fs->fs_bsize || fragoff(fs, size) != 0 ||
            fragnum(fs, bno) + numfrags(fs, size) > fs->fs_frag) {
                kprintf("dev=%s, bno = %ld, bsize = %ld, size = %ld, fs = %s\n",
                    devtoname(i_dev), (long)bno, (long)fs->fs_bsize, size,
                    fs->fs_fsmnt);
                panic("ffs_blkfree: bad size");
        }
        cg = dtog(fs, bno);
        if ((uint)bno >= fs->fs_size) {
                kprintf("bad block %ld, ino %lu\n",
                    (long)bno, (u_long)i_number);
                ffs_fserr(fs, i_din_uid, "bad block");
                return;
        }

        /*
         * Load the cylinder group
         */
        error = bread(i_devvp, fsbtodoff(fs, cgtod(fs, cg)),
                      (int)fs->fs_cgsize, &bp);
        if (error) {
                brelse(bp);
                return;
        }
        cgp = (struct cg *)bp->b_data;
        if (!cg_chkmagic(cgp)) {
                brelse(bp);
                return;
        }
        cgp->cg_time = time_second;
        bno = dtogd(fs, bno);
        blksfree = cg_blksfree(cgp);

        if (size == fs->fs_bsize) {
                /*
                 * Free a whole block
                 */
                blkno = fragstoblks(fs, bno);
                if (!ffs_isfreeblock(fs, blksfree, blkno)) {
                        kprintf("dev = %s, block = %ld, fs = %s\n",
                            devtoname(i_dev), (long)bno, fs->fs_fsmnt);
                        panic("ffs_blkfree: freeing free block");
                }
                ffs_setblock(fs, blksfree, blkno);
                ffs_clusteracct(fs, cgp, blkno, 1);
                cgp->cg_cs.cs_nbfree++;
                fs->fs_cstotal.cs_nbfree++;
                fs->fs_cs(fs, cg).cs_nbfree++;
                i = cbtocylno(fs, bno);
                cg_blks(fs, cgp, i)[cbtorpos(fs, bno)]++;
                cg_blktot(cgp)[i]++;
        } else {
                /*
                 * Free a fragment within a block.
                 *
                 * bno is the starting block number of the fragment being
                 * freed.
                 *
                 * bbase is the starting block number for the filesystem
                 * block containing the fragment.
                 *
                 * blk is the current bitmap for the fragments within the
                 * filesystem block containing the fragment.
                 *
                 * frags is the number of fragments being freed
                 *
                 * Call ffs_fragacct() to account for the removal of all
                 * current fragments, then adjust the bitmap to free the
                 * requested fragment, and finally call ffs_fragacct() again
                 * to regenerate the accounting.
                 */
                bbase = bno - fragnum(fs, bno);
                blk = blkmap(fs, blksfree, bbase);
                ffs_fragacct(fs, blk, cgp->cg_frsum, -1);
                frags = numfrags(fs, size);
                for (i = 0; i < frags; i++) {
                        if (isset(blksfree, bno + i)) {
                                kprintf("dev = %s, block = %ld, fs = %s\n",
                                    devtoname(i_dev), (long)(bno + i),
                                    fs->fs_fsmnt);
                                panic("ffs_blkfree: freeing free frag");
                        }
                        setbit(blksfree, 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, blksfree, 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, blksfree, 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++;
                        i = cbtocylno(fs, bbase);
                        cg_blks(fs, cgp, i)[cbtorpos(fs, bbase)]++;
                        cg_blktot(cgp)[i]++;
                }
        }
        fs->fs_fmod = 1;
        bdwrite(bp);
}

struct ffs_blkfree_trim_params {
        struct task task;
        ufs_daddr_t bno;
        long size;

        /* 
         * With TRIM,  inode pointer is gone in the callback but we still need 
         * the following fields for  ffs_blkfree_cg() 
         */
        struct vnode *i_devvp;
        struct fs *i_fs;
        cdev_t i_dev; 
        ino_t i_number;
        uint32_t i_din_uid;
};

        
static void
ffs_blkfree_trim_task(void *ctx, int pending)
{
        struct ffs_blkfree_trim_params *tp;

        tp = ctx;
        ffs_blkfree_cg(tp->i_fs, tp->i_devvp, tp->i_dev, tp->i_number,
            tp->i_din_uid, tp->bno, tp->size);
        kfree(tp, M_TEMP);
}



static void
ffs_blkfree_trim_completed(struct bio *biop)
{
        struct buf *bp = biop->bio_buf;
        struct ffs_blkfree_trim_params *tp;

        tp = bp->b_bio1.bio_caller_info1.ptr;
        TASK_INIT(&tp->task, 0, ffs_blkfree_trim_task, tp);
        tp = biop->bio_caller_info1.ptr;
        taskqueue_enqueue(taskqueue_swi, &tp->task);
        biodone(biop);
}


/*
 * If TRIM is enabled, we TRIM the blocks first then free them. We do this 
 * after TRIM is finished and the callback handler is called. The logic here
 * is that we free the blocks before updating the bitmap so that we don't
 * reuse a block before we actually trim it, which would result in trimming
 * a valid block.
 */
void
ffs_blkfree(struct inode *ip, ufs_daddr_t bno, long size) 
{
        struct mount *mp = ip->i_devvp->v_mount;
        struct ffs_blkfree_trim_params *tp;

        if (!(mp->mnt_flag & MNT_TRIM)) {
                ffs_blkfree_cg(ip->i_fs, ip->i_devvp,ip->i_dev,ip->i_number,
                    ip->i_uid, bno, size);
                return;
        }

        struct buf *bp; 

        tp = kmalloc(sizeof(struct ffs_blkfree_trim_params), M_TEMP, M_WAITOK);
        tp->bno = bno;
        tp->i_fs= ip->i_fs;
        tp->i_devvp = ip->i_devvp;
        tp->i_dev = ip->i_dev;
        tp->i_din_uid = ip->i_uid;
        tp->i_number = ip->i_number;
        tp->size = size;

        bp = getnewbuf(0, 0, 0, 1);
        BUF_KERNPROC(bp);
        bp->b_cmd = BUF_CMD_FREEBLKS;
        bp->b_bio1.bio_offset =  fsbtodoff(ip->i_fs, bno);
        bp->b_bcount = size;
        bp->b_bio1.bio_caller_info1.ptr = tp;
        bp->b_bio1.bio_done = ffs_blkfree_trim_completed;
        vn_strategy(ip->i_devvp, &bp->b_bio1);  
}

#ifdef DIAGNOSTIC
/*
 * Verify allocation of a block or fragment. Returns true if block or
 * fragment is allocated, false if it is free.
 */
static int
ffs_checkblk(struct inode *ip, ufs_daddr_t bno, long size)
{
        struct fs *fs;
        struct cg *cgp;
        struct buf *bp;
        int i, error, frags, free;
        uint8_t *blksfree;

        fs = ip->i_fs;
        if ((uint)size > fs->fs_bsize || fragoff(fs, size) != 0) {
                kprintf("bsize = %ld, size = %ld, fs = %s\n",
                    (long)fs->fs_bsize, size, fs->fs_fsmnt);
                panic("ffs_checkblk: bad size");
        }
        if ((uint)bno >= fs->fs_size)
                panic("ffs_checkblk: bad block %d", bno);
        error = bread(ip->i_devvp, fsbtodoff(fs, cgtod(fs, dtog(fs, bno))),
                      (int)fs->fs_cgsize, &bp);
        if (error)
                panic("ffs_checkblk: cg bread failed");
        cgp = (struct cg *)bp->b_data;
        if (!cg_chkmagic(cgp))
                panic("ffs_checkblk: cg magic mismatch");
        blksfree = cg_blksfree(cgp);
        bno = dtogd(fs, bno);
        if (size == fs->fs_bsize) {
                free = ffs_isblock(fs, blksfree, fragstoblks(fs, bno));
        } else {
                frags = numfrags(fs, size);
                for (free = 0, i = 0; i < frags; i++)
                        if (isset(blksfree, bno + i))
                                free++;
                if (free != 0 && free != frags)
                        panic("ffs_checkblk: partially free fragment");
        }
        brelse(bp);
        return (!free);
}
#endif /* DIAGNOSTIC */

/*
 * Free an inode.
 */
int
ffs_vfree(struct vnode *pvp, ino_t ino, int mode)
{
        if (DOINGSOFTDEP(pvp)) {
                softdep_freefile(pvp, ino, mode);
                return (0);
        }
        return (ffs_freefile(pvp, ino, mode));
}

/*
 * Do the actual free operation.
 * The specified inode is placed back in the free map.
 */
int
ffs_freefile(struct vnode *pvp, ino_t ino, int mode)
{
        struct fs *fs;
        struct cg *cgp;
        struct inode *pip;
        struct buf *bp;
        int error, cg;
        uint8_t *inosused;

        pip = VTOI(pvp);
        fs = pip->i_fs;
        if ((uint)ino >= fs->fs_ipg * fs->fs_ncg)
                panic("ffs_vfree: range: dev = (%d,%d), ino = %"PRId64", fs = %s",
                    major(pip->i_dev), minor(pip->i_dev), ino, fs->fs_fsmnt);
        cg = ino_to_cg(fs, ino);
        error = bread(pip->i_devvp, fsbtodoff(fs, cgtod(fs, cg)),
                      (int)fs->fs_cgsize, &bp);
        if (error) {
                brelse(bp);
                return (error);
        }
        cgp = (struct cg *)bp->b_data;
        if (!cg_chkmagic(cgp)) {
                brelse(bp);
                return (0);
        }
        cgp->cg_time = time_second;
        inosused = cg_inosused(cgp);
        ino %= fs->fs_ipg;
        if (isclr(inosused, ino)) {
                kprintf("dev = %s, ino = %lu, fs = %s\n",
                    devtoname(pip->i_dev), (u_long)ino, fs->fs_fsmnt);
                if (fs->fs_ronly == 0)
                        panic("ffs_vfree: freeing free inode");
        }
        clrbit(inosused, 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.
 */
static ufs_daddr_t
ffs_mapsearch(struct fs *fs, struct cg *cgp, ufs_daddr_t bpref, int allocsiz)
{
        ufs_daddr_t bno;
        int start, len, loc, i;
        int blk, field, subfield, pos;
        uint8_t *blksfree;

        /*
         * 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;
        blksfree = cg_blksfree(cgp);
        len = howmany(fs->fs_fpg, NBBY) - start;
        loc = scanc((uint)len, (u_char *)&blksfree[start],
                (u_char *)fragtbl[fs->fs_frag],
                (u_char)(1 << (allocsiz - 1 + (fs->fs_frag % NBBY))));
        if (loc == 0) {
                len = start + 1;        /* XXX why overlap here? */
                start = 0;
                loc = scanc((uint)len, (u_char *)&blksfree[0],
                        (u_char *)fragtbl[fs->fs_frag],
                        (u_char)(1 << (allocsiz - 1 + (fs->fs_frag % NBBY))));
                if (loc == 0) {
                        kprintf("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, blksfree, 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;
                }
        }
        kprintf("bno = %lu, fs = %s\n", (u_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.
 */
static void
ffs_clusteracct(struct fs *fs, struct cg *cgp, ufs_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;
}

/*
 * Fserr prints the name of a filesystem with an error diagnostic.
 *
 * The form of the error message is:
 *      fs: error message
 */
static void
ffs_fserr(struct fs *fs, uint uid, char *cp)
{
        struct thread *td = curthread;
        struct proc *p;

        if ((p = td->td_proc) != NULL) {
            log(LOG_ERR, "pid %d (%s), uid %d on %s: %s\n", p ? p->p_pid : -1,
                    p ? p->p_comm : "-", uid, fs->fs_fsmnt, cp);
        } else {
            log(LOG_ERR, "system thread %p, uid %d on %s: %s\n",
                    td, uid, fs->fs_fsmnt, cp);
        }
}