FreeBSD/Linux Kernel Cross Reference
sys/ufs/ffs/ffs_alloc.c

     /*      $NetBSD: ffs_alloc.c,v 1.74.2.1 2004/04/27 17:55:26 jdc 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 8.19 (Berkeley) 7/13/95
     */
    
    #include <sys/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: ffs_alloc.c,v 1.74.2.1 2004/04/27 17:55:26 jdc Exp $");
    
    #if defined(_KERNEL_OPT)
    #include "opt_ffs.h"
    #include "opt_quota.h"
    #endif
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/buf.h>
    #include <sys/proc.h>
    #include <sys/vnode.h>
    #include <sys/mount.h>
    #include <sys/kernel.h>
    #include <sys/syslog.h>
    
    #include <ufs/ufs/quota.h>
    #include <ufs/ufs/ufsmount.h>
    #include <ufs/ufs/inode.h>
    #include <ufs/ufs/ufs_extern.h>
    #include <ufs/ufs/ufs_bswap.h>
    
    #include <ufs/ffs/fs.h>
    #include <ufs/ffs/ffs_extern.h>
    
    static daddr_t ffs_alloccg __P((struct inode *, int, daddr_t, int));
    static daddr_t ffs_alloccgblk __P((struct inode *, struct buf *, daddr_t));
    #ifdef XXXUBC
    static daddr_t ffs_clusteralloc __P((struct inode *, int, daddr_t, int));
    #endif
    static ino_t ffs_dirpref __P((struct inode *));
    static daddr_t ffs_fragextend __P((struct inode *, int, daddr_t, int, int));
    static void ffs_fserr __P((struct fs *, u_int, char *));
    static daddr_t ffs_hashalloc __P((struct inode *, int, daddr_t, int,
        daddr_t (*)(struct inode *, int, daddr_t, int)));
    static daddr_t ffs_nodealloccg __P((struct inode *, int, daddr_t, int));
    static int32_t ffs_mapsearch __P((struct fs *, struct cg *,
                                          daddr_t, int));
    #if defined(DIAGNOSTIC) || defined(DEBUG)
    #ifdef XXXUBC
    static int ffs_checkblk __P((struct inode *, daddr_t, long size));
    #endif
    #endif
    
    /* if 1, changes in optimalization strategy are logged */
    int ffs_log_changeopt = 0;
    
    /* in ffs_tables.c */
    extern const int inside[], around[];
    extern const u_char * const fragtbl[];
    
    /*
     * 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) quadradically 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) quadradically rehash into other cylinder groups, until an
    *      available block is located.
    */
   int
   ffs_alloc(ip, lbn, bpref, size, cred, bnp)
           struct inode *ip;
           daddr_t lbn, bpref;
           int size;
           struct ucred *cred;
           daddr_t *bnp;
   {
           struct fs *fs;
           daddr_t bno;
           int cg;
   #ifdef QUOTA
           int error;
   #endif
           
           fs = ip->i_fs;
   
   #ifdef UVM_PAGE_TRKOWN
           if (ITOV(ip)->v_type == VREG &&
               lblktosize(fs, (voff_t)lbn) < round_page(ITOV(ip)->v_size)) {
                   struct vm_page *pg;
                   struct uvm_object *uobj = &ITOV(ip)->v_uobj;
                   voff_t off = trunc_page(lblktosize(fs, lbn));
                   voff_t endoff = round_page(lblktosize(fs, lbn) + size);
   
                   simple_lock(&uobj->vmobjlock);
                   while (off < endoff) {
                           pg = uvm_pagelookup(uobj, off);
                           KASSERT(pg != NULL);
                           KASSERT(pg->owner == curproc->p_pid);
                           KASSERT((pg->flags & PG_CLEAN) == 0);
                           off += PAGE_SIZE;
                   }
                   simple_unlock(&uobj->vmobjlock);
           }
   #endif
   
           *bnp = 0;
   #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;
   #ifdef QUOTA
           if ((error = chkdq(ip, btodb(size), cred, 0)) != 0)
                   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 = ffs_hashalloc(ip, cg, (long)bpref, size,
                                        ffs_alloccg);
           if (bno > 0) {
                   DIP_ADD(ip, 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) chkdq(ip, -btodb(size), cred, FORCE);
   #endif
   nospace:
           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(ip, lbprev, bpref, osize, nsize, cred, bpp, blknop)
           struct inode *ip;
           daddr_t lbprev;
           daddr_t bpref;
           int osize, nsize;
           struct ucred *cred;
           struct buf **bpp;
           daddr_t *blknop;
   {
           struct fs *fs;
           struct buf *bp;
           int cg, request, error;
           daddr_t bprev, bno;
   
           fs = ip->i_fs;
   #ifdef UVM_PAGE_TRKOWN
           if (ITOV(ip)->v_type == VREG) {
                   struct vm_page *pg;
                   struct uvm_object *uobj = &ITOV(ip)->v_uobj;
                   voff_t off = trunc_page(lblktosize(fs, lbprev));
                   voff_t endoff = round_page(lblktosize(fs, lbprev) + osize);
   
                   simple_lock(&uobj->vmobjlock);
                   while (off < endoff) {
                           pg = uvm_pagelookup(uobj, off);
                           KASSERT(pg != NULL);
                           KASSERT(pg->owner == curproc->p_pid);
                           KASSERT((pg->flags & PG_CLEAN) == 0);
                           off += PAGE_SIZE;
                   }
                   simple_unlock(&uobj->vmobjlock);
           }
   #endif
   
   #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;
           if (fs->fs_magic == FS_UFS2_MAGIC)
                   bprev = ufs_rw64(ip->i_ffs2_db[lbprev], UFS_FSNEEDSWAP(fs));
           else
                   bprev = ufs_rw32(ip->i_ffs1_db[lbprev], UFS_FSNEEDSWAP(fs));
   
           if (bprev == 0) {
                   printf("dev = 0x%x, bsize = %d, bprev = %" PRId64 ", fs = %s\n",
                       ip->i_dev, fs->fs_bsize, bprev, fs->fs_fsmnt);
                   panic("ffs_realloccg: bad bprev");
           }
           /*
            * Allocate the extra space in the buffer.
            */
           if (bpp != NULL &&
               (error = bread(ITOV(ip), lbprev, osize, NOCRED, &bp)) != 0) {
                   brelse(bp);
                   return (error);
           }
   #ifdef QUOTA
           if ((error = chkdq(ip, btodb(nsize - osize), cred, 0)) != 0) {
                   if (bpp != NULL) {
                           brelse(bp);
                   }
                   return (error);
           }
   #endif
           /*
            * 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("bad blockno");
                           allocbuf(bp, nsize, 1);
                           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 ((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 >
                       fs->fs_dsize * fs->fs_minfree / (2 * 100))
                           break;
   
                   if (ffs_log_changeopt) {
                           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 <
                       fs->fs_dsize * (fs->fs_minfree - 2) / 100)
                           break;
   
                   if (ffs_log_changeopt) {
                           log(LOG_NOTICE,
                                   "%s: optimization changed from TIME to SPACE\n",
                                   fs->fs_fsmnt);
                   }
   
                   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) {
                   if (!DOINGSOFTDEP(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);
                           allocbuf(bp, nsize, 1);
                           bp->b_flags |= B_DONE;
                           memset(bp->b_data + osize, 0, (u_int)nsize - osize);
                           *bpp = bp;
                   }
                   if (blknop != NULL) {
                           *blknop = bno;
                   }
                   return (0);
           }
   #ifdef QUOTA
           /*
            * Restore user's disk quota because allocation failed.
            */
           (void) chkdq(ip, -btodb(nsize - osize), cred, FORCE);
   #endif
           if (bpp != NULL) {
                   brelse(bp);
           }
   
   nospace:
           /*
            * no space available
            */
           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 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
    * from the end of the allocation for the logical block immediately
    * preceding 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.
   
    */
   #ifdef XXXUBC
   #ifdef DEBUG
   #include <sys/sysctl.h>
   int prtrealloc = 0;
   struct ctldebug debug15 = { "prtrealloc", &prtrealloc };
   #endif
   #endif
   
   /*
    * NOTE: when re-enabling this, it must be updated for UFS2.
    */
   
   int doasyncfree = 1;
   
   int
   ffs_reallocblks(v)
           void *v;
   {
   #ifdef XXXUBC
           struct vop_reallocblks_args /* {
                   struct vnode *a_vp;
                   struct cluster_save *a_buflist;
           } */ *ap = v;
           struct fs *fs;
           struct inode *ip;
           struct vnode *vp;
           struct buf *sbp, *ebp;
           int32_t *bap, *ebap = NULL, *sbap;      /* XXX ondisk32 */
           struct cluster_save *buflist;
           daddr_t start_lbn, end_lbn, soff, newblk, blkno;
           struct indir start_ap[NIADDR + 1], end_ap[NIADDR + 1], *idp;
           int i, len, start_lvl, end_lvl, pref, ssize;
   #endif /* XXXUBC */
   
           /* XXXUBC don't reallocblks for now */
           return ENOSPC;
   
   #ifdef XXXUBC
           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 = buflist->bs_children[0]->b_lblkno;
           end_lbn = start_lbn + len - 1;
   #ifdef DIAGNOSTIC
           for (i = 0; i < len; i++)
                   if (!ffs_checkblk(ip,
                      dbtofsb(fs, buflist->bs_children[i]->b_blkno), fs->fs_bsize))
                           panic("ffs_reallocblks: unallocated block 1");
           for (i = 1; i < len; i++)
                   if (buflist->bs_children[i]->b_lblkno != start_lbn + i)
                           panic("ffs_reallocblks: non-logical cluster");
           blkno = buflist->bs_children[0]->b_blkno;
           ssize = fsbtodb(fs, fs->fs_frag);
           for (i = 1; i < len - 1; i++)
                   if (buflist->bs_children[i]->b_blkno != blkno + (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, dbtofsb(fs, buflist->bs_children[0]->b_blkno)) !=
               dtog(fs, dbtofsb(fs, buflist->bs_children[len - 1]->b_blkno)))
                   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.
            */
           if (start_lvl == 0) {
                   sbap = &ip->i_ffs1_db[0];
                   soff = start_lbn;
           } else {
                   idp = &start_ap[start_lvl - 1];
                   if (bread(vp, idp->in_lbn, (int)fs->fs_bsize, NOCRED, &sbp)) {
                           brelse(sbp);
                           return (ENOSPC);
                   }
                   sbap = (int32_t *)sbp->b_data;
                   soff = idp->in_off;
           }
           /*
            * 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, idp->in_lbn, (int)fs->fs_bsize, NOCRED, &ebp))
                           goto fail;
                   ebap = (int32_t *)ebp->b_data;  /* XXX ondisk32 */
           }
           /*
            * Search the block map looking for an allocation of the desired size.
            */
           if ((newblk = (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)
                   printf("realloc: ino %d, lbns %d-%d\n\told:", ip->i_number,
                       start_lbn, end_lbn);
   #endif
           blkno = newblk;
           for (bap = &sbap[soff], i = 0; i < len; i++, blkno += fs->fs_frag) {
                   daddr_t ba;
   
                   if (i == ssize) {
                           bap = ebap;
                           soff = -i;
                   }
                   /* XXX ondisk32 */
                   ba = ufs_rw32(*bap, UFS_FSNEEDSWAP(fs));
   #ifdef DIAGNOSTIC
                   if (!ffs_checkblk(ip,
                      dbtofsb(fs, buflist->bs_children[i]->b_blkno), fs->fs_bsize))
                           panic("ffs_reallocblks: unallocated block 2");
                   if (dbtofsb(fs, buflist->bs_children[i]->b_blkno) != ba)
                           panic("ffs_reallocblks: alloc mismatch");
   #endif
   #ifdef DEBUG
                   if (prtrealloc)
                           printf(" %d,", ba);
   #endif
                   if (DOINGSOFTDEP(vp)) {
                           if (sbap == &ip->i_ffs1_db[0] && i < ssize)
                                   softdep_setup_allocdirect(ip, start_lbn + i,
                                       blkno, ba, 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,
                                       ba, buflist->bs_children[i]);
                   }
                   /* XXX ondisk32 */
                   *bap++ = ufs_rw32((int32_t)blkno, UFS_FSNEEDSWAP(fs));
           }
           /*
            * 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_ffs1_db[0]) {
                   if (doasyncfree)
                           bdwrite(sbp);
                   else
                           bwrite(sbp);
           } else {
                   ip->i_flag |= IN_CHANGE | IN_UPDATE;
                   if (!doasyncfree)
                           VOP_UPDATE(vp, NULL, NULL, 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)
                   printf("\n\tnew:");
   #endif
           for (blkno = newblk, i = 0; i < len; i++, blkno += fs->fs_frag) {
                   if (!DOINGSOFTDEP(vp))
                           ffs_blkfree(ip,
                               dbtofsb(fs, buflist->bs_children[i]->b_blkno),
                               fs->fs_bsize);
                   buflist->bs_children[i]->b_blkno = fsbtodb(fs, blkno);
   #ifdef DEBUG
                   if (!ffs_checkblk(ip,
                      dbtofsb(fs, buflist->bs_children[i]->b_blkno), fs->fs_bsize))
                           panic("ffs_reallocblks: unallocated block 3");
                   if (prtrealloc)
                           printf(" %d,", blkno);
   #endif
           }
   #ifdef DEBUG
           if (prtrealloc) {
                   prtrealloc--;
                   printf("\n");
           }
   #endif
           return (0);
   
   fail:
           if (ssize < len)
                   brelse(ebp);
           if (sbap != &ip->i_ffs1_db[0])
                   brelse(sbp);
           return (ENOSPC);
   #endif /* XXXUBC */
   }
   
   /*
    * 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) quadradically 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) quadradically rehash into other cylinder groups, until an
    *      available inode is located.
    */
   int
   ffs_valloc(v)
           void *v;
   {
           struct vop_valloc_args /* {
                   struct vnode *a_pvp;
                   int a_mode;
                   struct ucred *a_cred;
                   struct vnode **a_vpp;
           } */ *ap = v;
           struct vnode *pvp = ap->a_pvp;
           struct inode *pip;
           struct fs *fs;
           struct inode *ip;
           struct timespec ts;
           mode_t mode = ap->a_mode;
           ino_t ino, ipref;
           int cg, error;
           
           *ap->a_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, ipref, mode, ffs_nodealloccg);
           if (ino == 0)
                   goto noinodes;
           error = VFS_VGET(pvp->v_mount, ino, ap->a_vpp);
           if (error) {
                   VOP_VFREE(pvp, ino, mode);
                   return (error);
           }
           ip = VTOI(*ap->a_vpp);
           if (ip->i_mode) {
   #if 0
                   printf("mode = 0%o, inum = %d, fs = %s\n",
                       ip->i_mode, ip->i_number, fs->fs_fsmnt);
   #else
                   printf("dmode %x mode %x dgen %x gen %x\n",
                       DIP(ip, mode), ip->i_mode,
                       DIP(ip, gen), ip->i_gen);
                   printf("size %llx blocks %llx\n",
                       (long long)DIP(ip, size), (long long)DIP(ip, blocks));
                   printf("ino %u ipref %u\n", ino, ipref);
   #if 0
                   error = bread(ump->um_devvp, fsbtodb(fs, ino_to_fsba(fs, ino)),
                       (int)fs->fs_bsize, NOCRED, &bp);
   #endif
   
   #endif
                   panic("ffs_valloc: dup alloc");
           }
           if (DIP(ip, blocks)) {                          /* XXX */
                   printf("free inode %s/%d had %" PRId64 " blocks\n",
                       fs->fs_fsmnt, ino, DIP(ip, blocks));
                   DIP_ASSIGN(ip, blocks, 0);
           }
           ip->i_flag &= ~IN_SPACECOUNTED;
           ip->i_flags = 0;
           DIP_ASSIGN(ip, flags, 0);
           /*
            * Set up a new generation number for this inode.
            */
           ip->i_gen++;
           DIP_ASSIGN(ip, gen, ip->i_gen);
           if (fs->fs_magic == FS_UFS2_MAGIC) {
                   TIMEVAL_TO_TIMESPEC(&time, &ts);
                   ip->i_ffs2_birthtime = ts.tv_sec;
                   ip->i_ffs2_birthnsec = ts.tv_nsec;
           }
           return (0);
   noinodes:
           ffs_fserr(fs, ap->a_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 in which 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(pip)
           struct inode *pip;
   {
           register struct fs *fs;
           int cg, prefcg;
           int64_t dirsize, cgsize;
           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 = random() % 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 - fs->fs_ipg / 4;
           if (minifree < 0)
                   minifree = 0;
           minbfree = avgbfree - fragstoblks(fs, fs->fs_fpg) / 4;
           if (minbfree < 0)
                   minbfree = 0;
           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;
           maxcontigdirs = min(cgsize / 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 are deficient 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 laid out
    * contigously if possible.
    */
   daddr_t
   ffs_blkpref_ufs1(ip, lbn, indx, bap)
           struct inode *ip;
           daddr_t lbn;
           int indx;
           int32_t *bap;   /* XXX ondisk32 */
   {
           struct fs *fs;
           int cg;
           int avgbfree, startcg;
   
           fs = ip->i_fs;
           if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) {
                   if (lbn < 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,
                                   ufs_rw32(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + 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 (fs->fs_fpg * cg + fs->fs_frag);
                           }
                   for (cg = 0; cg < startcg; cg++)
                           if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
                                   return (fs->fs_fpg * cg + fs->fs_frag);
                           }
                   return (0);
           }
           /*
            * We just always try to lay things out contiguously.
            */
           return ufs_rw32(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + fs->fs_frag;
   }
   
   daddr_t
   ffs_blkpref_ufs2(ip, lbn, indx, bap)
           struct inode *ip;
           daddr_t lbn;
           int indx;
           int64_t *bap;
   {
           struct fs *fs;
           int cg;
           int avgbfree, startcg;
   
           fs = ip->i_fs;
           if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) {
                   if (lbn < 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,
                                   ufs_rw64(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + 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 (fs->fs_fpg * cg + fs->fs_frag);
                           }
                   for (cg = 0; cg < startcg; cg++)
                           if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
                                   return (fs->fs_fpg * cg + fs->fs_frag);
                           }
                   return (0);
           }
           /*
            * We just always try to lay things out contiguously.
            */
           return ufs_rw64(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + fs->fs_frag;
   }
   
   
   /*
    * 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 daddr_t
   ffs_hashalloc(ip, cg, pref, size, allocator)
           struct inode *ip;
           int cg;
           daddr_t pref;
           int size;       /* size for data blocks, mode for inodes */
           daddr_t (*allocator) __P((struct inode *, int, daddr_t, int));
   {
           struct fs *fs;
           daddr_t result;
           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 daddr_t
  ffs_fragextend(ip, cg, bprev, osize, nsize)
          struct inode *ip;
          int cg;
          daddr_t bprev;
          int osize, nsize;
  {
          struct fs *fs;
          struct cg *cgp;
          struct buf *bp;
          daddr_t bno;
          int frags, bbase;
          int i, error;
          u_int8_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);
          }
          error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)),
                  (int)fs->fs_cgsize, NOCRED, &bp);
          if (error) {
                  brelse(bp);
                  return (0);
          }
          cgp = (struct cg *)bp->b_data;
          if (!cg_chkmagic(cgp, UFS_FSNEEDSWAP(fs))) {
                  brelse(bp);
                  return (0);
          }
          cgp->cg_old_time = ufs_rw32(time.tv_sec, UFS_FSNEEDSWAP(fs));
          if ((fs->fs_magic != FS_UFS1_MAGIC) ||
              (fs->fs_old_flags & FS_FLAGS_UPDATED))
                  cgp->cg_time = ufs_rw64(time.tv_sec, UFS_FSNEEDSWAP(fs));
          bno = dtogd(fs, bprev);
          blksfree = cg_blksfree(cgp, UFS_FSNEEDSWAP(fs));
          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
           */
          for (i = frags; i < fs->fs_frag - bbase; i++)
                  if (isclr(blksfree, bno + i))
                          break;
          ufs_add32(cgp->cg_frsum[i - numfrags(fs, osize)], -1, UFS_FSNEEDSWAP(fs));
          if (i != frags)
                  ufs_add32(cgp->cg_frsum[i - frags], 1, UFS_FSNEEDSWAP(fs));
          for (i = numfrags(fs, osize); i < frags; i++) {
                  clrbit(blksfree, bno + i);
                  ufs_add32(cgp->cg_cs.cs_nffree, -1, UFS_FSNEEDSWAP(fs));
                  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 daddr_t
  ffs_alloccg(ip, cg, bpref, size)
          struct inode *ip;
          int cg;
          daddr_t bpref;
          int size;
  {
          struct fs *fs = ip->i_fs;
          struct cg *cgp;
          struct buf *bp;
          int32_t bno;
          daddr_t blkno;
          int error, frags, allocsiz, i;
          u_int8_t *blksfree;
  #ifdef FFS_EI
          const int needswap = UFS_FSNEEDSWAP(fs);
  #endif
  
          if (fs->fs_cs(fs, cg).cs_nbfree == 0 && size == fs->fs_bsize)
                  return (0);
          error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)),
                  (int)fs->fs_cgsize, NOCRED, &bp);
          if (error) {
                  brelse(bp);
                  return (0);
          }
          cgp = (struct cg *)bp->b_data;
          if (!cg_chkmagic(cgp, needswap) ||
              (cgp->cg_cs.cs_nbfree == 0 && size == fs->fs_bsize)) {
                  brelse(bp);
                  return (0);
          }
          cgp->cg_old_time = ufs_rw32(time.tv_sec, needswap);
          if ((fs->fs_magic != FS_UFS1_MAGIC) ||
              (fs->fs_old_flags & FS_FLAGS_UPDATED))
                  cgp->cg_time = ufs_rw64(time.tv_sec, needswap);
          if (size == fs->fs_bsize) {
                  blkno = ffs_alloccgblk(ip, bp, bpref);
                  bdwrite(bp);
                  return (blkno);
          }
          /*
           * 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
           */
          blksfree = cg_blksfree(cgp, needswap);
          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);
                  }
                  blkno = ffs_alloccgblk(ip, bp, bpref);
                  bno = dtogd(fs, blkno);
                  for (i = frags; i < fs->fs_frag; i++)
                          setbit(blksfree, bno + i);
                  i = fs->fs_frag - frags;
                  ufs_add32(cgp->cg_cs.cs_nffree, i, needswap);
                  fs->fs_cstotal.cs_nffree += i;
                  fs->fs_cs(fs, cg).cs_nffree += i;
                  fs->fs_fmod = 1;
                  ufs_add32(cgp->cg_frsum[i], 1, needswap);
                  bdwrite(bp);
                  return (blkno);
          }
          bno = ffs_mapsearch(fs, cgp, bpref, allocsiz);
  #if 0
          /*
           * XXX fvdl mapsearch will panic, and never return -1
           *          also: returning NULL as daddr_t ?
           */
          if (bno < 0) {
                  brelse(bp);
                  return (0);
          }
  #endif
          for (i = 0; i < frags; i++)
                  clrbit(blksfree, bno + i);
          ufs_add32(cgp->cg_cs.cs_nffree, -frags, needswap);
          fs->fs_cstotal.cs_nffree -= frags;
          fs->fs_cs(fs, cg).cs_nffree -= frags;
          fs->fs_fmod = 1;
          ufs_add32(cgp->cg_frsum[allocsiz], -1, needswap);
          if (frags != allocsiz)
                  ufs_add32(cgp->cg_frsum[allocsiz - frags], 1, needswap);
          blkno = cg * fs->fs_fpg + bno;
          if (DOINGSOFTDEP(ITOV(ip)))
                  softdep_setup_blkmapdep(bp, fs, blkno);
          bdwrite(bp);
          return 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 daddr_t
  ffs_alloccgblk(ip, bp, bpref)
          struct inode *ip;
          struct buf *bp;
          daddr_t bpref;
  {
          struct fs *fs = ip->i_fs;
          struct cg *cgp;
          daddr_t blkno;
          int32_t bno;
          u_int8_t *blksfree;
  #ifdef FFS_EI
          const int needswap = UFS_FSNEEDSWAP(fs);
  #endif
  
          cgp = (struct cg *)bp->b_data;
          blksfree = cg_blksfree(cgp, needswap);
          if (bpref == 0 || dtog(fs, bpref) != ufs_rw32(cgp->cg_cgx, needswap)) {
                  bpref = ufs_rw32(cgp->cg_rotor, needswap);
          } else {
                  bpref = blknum(fs, bpref);
                  bno = dtogd(fs, bpref);
                  /*
                   * if the requested block is available, use it
                   */
                  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);
          cgp->cg_rotor = ufs_rw32(bno, needswap);
  gotit:
          blkno = fragstoblks(fs, bno);
          ffs_clrblock(fs, blksfree, blkno);
          ffs_clusteracct(fs, cgp, blkno, -1);
          ufs_add32(cgp->cg_cs.cs_nbfree, -1, needswap);
          fs->fs_cstotal.cs_nbfree--;
          fs->fs_cs(fs, ufs_rw32(cgp->cg_cgx, needswap)).cs_nbfree--;
          if ((fs->fs_magic == FS_UFS1_MAGIC) &&
              ((fs->fs_old_flags & FS_FLAGS_UPDATED) == 0)) {
                  int cylno;
                  cylno = old_cbtocylno(fs, bno);
                  KASSERT(cylno >= 0);
                  KASSERT(cylno < fs->fs_old_ncyl);
                  KASSERT(old_cbtorpos(fs, bno) >= 0);
                  KASSERT(fs->fs_old_nrpos == 0 || old_cbtorpos(fs, bno) < fs->fs_old_nrpos);
                  ufs_add16(old_cg_blks(fs, cgp, cylno, needswap)[old_cbtorpos(fs, bno)], -1,
                      needswap);
                  ufs_add32(old_cg_blktot(cgp, needswap)[cylno], -1, needswap);
          }
          fs->fs_fmod = 1;
          blkno = ufs_rw32(cgp->cg_cgx, needswap) * fs->fs_fpg + bno;
          if (DOINGSOFTDEP(ITOV(ip)))
                  softdep_setup_blkmapdep(bp, fs, blkno);
          return (blkno);
  }
  
  #ifdef XXXUBC
  /*
   * 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.
   */
  
  /*
   * This function must be fixed for UFS2 if re-enabled.
   */
  static daddr_t
  ffs_clusteralloc(ip, cg, bpref, len)
          struct inode *ip;
          int cg;
          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;
  
          fs = ip->i_fs;
          if (fs->fs_maxcluster[cg] < len)
                  return (0);
          if (bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)), (int)fs->fs_cgsize,
              NOCRED, &bp))
                  goto fail;
          cgp = (struct cg *)bp->b_data;
          if (!cg_chkmagic(cgp, UFS_FSNEEDSWAP(fs)))
                  goto fail;
          /*
           * Check to see if a cluster of the needed size (or bigger) is
           * available in this cylinder group.
           */
          lp = &cg_clustersum(cgp, UFS_FSNEEDSWAP(fs))[len];
          for (i = len; i <= fs->fs_contigsumsize; i++)
                  if (ufs_rw32(*lp++, UFS_FSNEEDSWAP(fs)) > 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, UFS_FSNEEDSWAP(fs))[len - 1];
                  for (i = len - 1; i > 0; i--)
                          if (ufs_rw32(*lp--, UFS_FSNEEDSWAP(fs)) > 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, UFS_FSNEEDSWAP(fs))[bpref / NBBY];
          map = *mapp++;
          bit = 1 << (bpref % NBBY);
          for (run = 0, got = bpref;
                  got < ufs_rw32(cgp->cg_nclusterblks, UFS_FSNEEDSWAP(fs)); 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 == ufs_rw32(cgp->cg_nclusterblks, UFS_FSNEEDSWAP(fs)))
                  goto fail;
          /*
           * Allocate the cluster that we have found.
           */
  #ifdef DIAGNOSTIC
          for (i = 1; i <= len; i++)
                  if (!ffs_isblock(fs, cg_blksfree(cgp, UFS_FSNEEDSWAP(fs)),
                      got - run + i))
                          panic("ffs_clusteralloc: map mismatch");
  #endif
          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);
  }
  #endif /* XXXUBC */
  
  /*
   * 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.
   */
  static daddr_t
  ffs_nodealloccg(ip, cg, ipref, mode)
          struct inode *ip;
          int cg;
          daddr_t ipref;
          int mode;
  {
          struct fs *fs = ip->i_fs;
          struct cg *cgp;
          struct buf *bp, *ibp;
          u_int8_t *inosused;
          int error, start, len, loc, map, i;
          int32_t initediblk;
          struct ufs2_dinode *dp2;
  #ifdef FFS_EI
          const int needswap = UFS_FSNEEDSWAP(fs);
  #endif
  
          if (fs->fs_cs(fs, cg).cs_nifree == 0)
                  return (0);
          error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)),
                  (int)fs->fs_cgsize, NOCRED, &bp);
          if (error) {
                  brelse(bp);
                  return (0);
          }
          cgp = (struct cg *)bp->b_data;
          if (!cg_chkmagic(cgp, needswap) || cgp->cg_cs.cs_nifree == 0) {
                  brelse(bp);
                  return (0);
          }
          cgp->cg_old_time = ufs_rw32(time.tv_sec, needswap);
          if ((fs->fs_magic != FS_UFS1_MAGIC) ||
              (fs->fs_old_flags & FS_FLAGS_UPDATED))
                  cgp->cg_time = ufs_rw64(time.tv_sec, needswap);
          inosused = cg_inosused(cgp, needswap);
          if (ipref) {
                  ipref %= fs->fs_ipg;
                  if (isclr(inosused, ipref))
                          goto gotit;
          }
          start = ufs_rw32(cgp->cg_irotor, needswap) / NBBY;
          len = howmany(fs->fs_ipg - ufs_rw32(cgp->cg_irotor, needswap),
                  NBBY);
          loc = skpc(0xff, len, &inosused[start]);
          if (loc == 0) {
                  len = start + 1;
                  start = 0;
                  loc = skpc(0xff, len, &inosused[0]);
                  if (loc == 0) {
                          printf("cg = %d, irotor = %d, fs = %s\n",
                              cg, ufs_rw32(cgp->cg_irotor, needswap),
                                  fs->fs_fsmnt);
                          panic("ffs_nodealloccg: map corrupted");
                          /* NOTREACHED */
                  }
          }
          i = start + len - loc;
          map = inosused[i];
          ipref = i * NBBY;
          for (i = 1; i < (1 << NBBY); i <<= 1, ipref++) {
                  if ((map & i) == 0) {
                          cgp->cg_irotor = ufs_rw32(ipref, needswap);
                          goto gotit;
                  }
          }
          printf("fs = %s\n", fs->fs_fsmnt);
          panic("ffs_nodealloccg: block not in map");
          /* NOTREACHED */
  gotit:
          if (DOINGSOFTDEP(ITOV(ip)))
                  softdep_setup_inomapdep(bp, ip, cg * fs->fs_ipg + ipref);
          setbit(inosused, ipref);
          ufs_add32(cgp->cg_cs.cs_nifree, -1, needswap);
          fs->fs_cstotal.cs_nifree--;
          fs->fs_cs(fs, cg).cs_nifree--;
          fs->fs_fmod = 1;
          if ((mode & IFMT) == IFDIR) {
                  ufs_add32(cgp->cg_cs.cs_ndir, 1, needswap);
                  fs->fs_cstotal.cs_ndir++;
                  fs->fs_cs(fs, cg).cs_ndir++;
          }
          /*
           * Check to see if we need to initialize more inodes.
           */
          initediblk = ufs_rw32(cgp->cg_initediblk, needswap);
          if (fs->fs_magic == FS_UFS2_MAGIC &&
              ipref + INOPB(fs) > initediblk &&
              initediblk < ufs_rw32(cgp->cg_niblk, needswap)) {
                  ibp = getblk(ip->i_devvp, fsbtodb(fs,
                      ino_to_fsba(fs, cg * fs->fs_ipg + initediblk)),
                      (int)fs->fs_bsize, 0, 0);
                      memset(ibp->b_data, 0, fs->fs_bsize);
                      dp2 = (struct ufs2_dinode *)(ibp->b_data);
                      for (i = 0; i < INOPB(fs); i++) {
                          /*
                           * Don't bother to swap, it's supposed to be
                           * random, after all.
                           */
                          dp2->di_gen = (arc4random() & INT32_MAX) / 2 + 1;
                          dp2++;
                  }
                  bawrite(ibp);
                  initediblk += INOPB(fs);
                  cgp->cg_initediblk = ufs_rw32(initediblk, needswap);
          }
  
          bdwrite(bp);
          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(ip, bno, size)
          struct inode *ip;
          daddr_t bno;
          long size;
  {
          struct fs *fs = ip->i_fs;
          struct cg *cgp;
          struct buf *bp;
          int32_t fragno, cgbno;
          int i, error, cg, blk, frags, bbase;
          u_int8_t *blksfree;
          const int needswap = UFS_FSNEEDSWAP(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, bno = %" PRId64 " bsize = %d, "
                         "size = %ld, fs = %s\n",
                      ip->i_dev, bno, fs->fs_bsize, size, fs->fs_fsmnt);
                  panic("blkfree: bad size");
          }
          cg = dtog(fs, bno);
          if (bno >= fs->fs_size) {
                  printf("bad block %" PRId64 ", ino %d\n", bno, ip->i_number);
                  ffs_fserr(fs, ip->i_uid, "bad block");
                  return;
          }
          error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)),
                  (int)fs->fs_cgsize, NOCRED, &bp);
          if (error) {
                  brelse(bp);
                  return;
          }
          cgp = (struct cg *)bp->b_data;
          if (!cg_chkmagic(cgp, needswap)) {
                  brelse(bp);
                  return;
          }
          cgp->cg_old_time = ufs_rw32(time.tv_sec, needswap);
          if ((fs->fs_magic != FS_UFS1_MAGIC) ||
              (fs->fs_old_flags & FS_FLAGS_UPDATED))
                  cgp->cg_time = ufs_rw64(time.tv_sec, needswap);
          cgbno = dtogd(fs, bno);
          blksfree = cg_blksfree(cgp, needswap);
          if (size == fs->fs_bsize) {
                  fragno = fragstoblks(fs, cgbno);
                  if (!ffs_isfreeblock(fs, blksfree, fragno)) {
                          printf("dev = 0x%x, block = %" PRId64 ", fs = %s\n",
                              ip->i_dev, bno, fs->fs_fsmnt);
                          panic("blkfree: freeing free block");
                  }
                  ffs_setblock(fs, blksfree, fragno);
                  ffs_clusteracct(fs, cgp, fragno, 1);
                  ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap);
                  fs->fs_cstotal.cs_nbfree++;
                  fs->fs_cs(fs, cg).cs_nbfree++;
                  if ((fs->fs_magic == FS_UFS1_MAGIC) &&
                      ((fs->fs_old_flags & FS_FLAGS_UPDATED) == 0)) {
                          i = old_cbtocylno(fs, cgbno);
                          KASSERT(i >= 0);
                          KASSERT(i < fs->fs_old_ncyl);
                          KASSERT(old_cbtorpos(fs, cgbno) >= 0);
                          KASSERT(fs->fs_old_nrpos == 0 || old_cbtorpos(fs, cgbno) < fs->fs_old_nrpos);
                          ufs_add16(old_cg_blks(fs, cgp, i, needswap)[old_cbtorpos(fs, cgbno)], 1,
                              needswap);
                          ufs_add32(old_cg_blktot(cgp, needswap)[i], 1, needswap);
                  }
          } else {
                  bbase = cgbno - fragnum(fs, cgbno);
                  /*
                   * decrement the counts associated with the old frags
                   */
                  blk = blkmap(fs, blksfree, bbase);
                  ffs_fragacct(fs, blk, cgp->cg_frsum, -1, needswap);
                  /*
                   * deallocate the fragment
                   */
                  frags = numfrags(fs, size);
                  for (i = 0; i < frags; i++) {
                          if (isset(blksfree, cgbno + i)) {
                                  printf("dev = 0x%x, block = %" PRId64
                                         ", fs = %s\n",
                                      ip->i_dev, bno + i, fs->fs_fsmnt);
                                  panic("blkfree: freeing free frag");
                          }
                          setbit(blksfree, cgbno + i);
                  }
                  ufs_add32(cgp->cg_cs.cs_nffree, i, needswap);
                  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, needswap);
                  /*
                   * if a complete block has been reassembled, account for it
                   */
                  fragno = fragstoblks(fs, bbase);
                  if (ffs_isblock(fs, blksfree, fragno)) {
                          ufs_add32(cgp->cg_cs.cs_nffree, -fs->fs_frag, needswap);
                          fs->fs_cstotal.cs_nffree -= fs->fs_frag;
                          fs->fs_cs(fs, cg).cs_nffree -= fs->fs_frag;
                          ffs_clusteracct(fs, cgp, fragno, 1);
                          ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap);
                          fs->fs_cstotal.cs_nbfree++;
                          fs->fs_cs(fs, cg).cs_nbfree++;
                          if ((fs->fs_magic == FS_UFS1_MAGIC) &&
                              ((fs->fs_old_flags & FS_FLAGS_UPDATED) == 0)) {
                                  i = old_cbtocylno(fs, bbase);
                                  KASSERT(i >= 0);
                                  KASSERT(i < fs->fs_old_ncyl);
                                  KASSERT(old_cbtorpos(fs, bbase) >= 0);
                                  KASSERT(fs->fs_old_nrpos == 0 || old_cbtorpos(fs, bbase) < fs->fs_old_nrpos);
                                  ufs_add16(old_cg_blks(fs, cgp, i, needswap)[old_cbtorpos(fs,
                                      bbase)], 1, needswap);
                                  ufs_add32(old_cg_blktot(cgp, needswap)[i], 1, needswap);
                          }
                  }
          }
          fs->fs_fmod = 1;
          bdwrite(bp);
  }
  
  #if defined(DIAGNOSTIC) || defined(DEBUG)
  #ifdef XXXUBC
  /*
   * Verify allocation of a block or fragment. Returns true if block or
   * fragment is allocated, false if it is free.
   */
  static int
  ffs_checkblk(ip, bno, size)
          struct inode *ip;
          daddr_t bno;
          long size;
  {
          struct fs *fs;
          struct cg *cgp;
          struct buf *bp;
          int i, error, frags, free;
  
          fs = ip->i_fs;
          if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0) {
                  printf("bsize = %d, size = %ld, fs = %s\n",
                      fs->fs_bsize, size, fs->fs_fsmnt);
                  panic("checkblk: bad size");
          }
          if (bno >= fs->fs_size)
                  panic("checkblk: bad block %d", bno);
          error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, dtog(fs, bno))),
                  (int)fs->fs_cgsize, NOCRED, &bp);
          if (error) {
                  brelse(bp);
                  return 0;
          }
          cgp = (struct cg *)bp->b_data;
          if (!cg_chkmagic(cgp, UFS_FSNEEDSWAP(fs))) {
                  brelse(bp);
                  return 0;
          }
          bno = dtogd(fs, bno);
          if (size == fs->fs_bsize) {
                  free = ffs_isblock(fs, cg_blksfree(cgp, UFS_FSNEEDSWAP(fs)),
                          fragstoblks(fs, bno));
          } else {
                  frags = numfrags(fs, size);
                  for (free = 0, i = 0; i < frags; i++)
                          if (isset(cg_blksfree(cgp, UFS_FSNEEDSWAP(fs)), bno + i))
                                  free++;
                  if (free != 0 && free != frags)
                          panic("checkblk: partially free fragment");
          }
          brelse(bp);
          return (!free);
  }
  #endif /* XXXUBC */
  #endif /* DIAGNOSTIC */
  
  /*
   * Free an inode.
   */
  int
  ffs_vfree(v)
          void *v;
  {
          struct vop_vfree_args /* {
                  struct vnode *a_pvp;
                  ino_t a_ino;
                  int a_mode;
          } */ *ap = v;
  
          if (DOINGSOFTDEP(ap->a_pvp)) {
                  softdep_freefile(ap);
                  return (0);
          }
          return (ffs_freefile(ap));
  }
  
  /*
   * Do the actual free operation.
   * The specified inode is placed back in the free map.
   */
  int
  ffs_freefile(v)
          void *v;
  {
          struct vop_vfree_args /* {
                  struct vnode *a_pvp;
                  ino_t a_ino;
                  int a_mode;
          } */ *ap = v;
          struct cg *cgp;
          struct inode *pip = VTOI(ap->a_pvp);
          struct fs *fs = pip->i_fs;
          ino_t ino = ap->a_ino;
          struct buf *bp;
          int error, cg;
          u_int8_t *inosused;
  #ifdef FFS_EI
          const int needswap = UFS_FSNEEDSWAP(fs);
  #endif
  
          if ((u_int)ino >= fs->fs_ipg * fs->fs_ncg)
                  panic("ifree: range: dev = 0x%x, ino = %d, fs = %s",
                      pip->i_dev, ino, fs->fs_fsmnt);
          cg = ino_to_cg(fs, ino);
          error = bread(pip->i_devvp, fsbtodb(fs, cgtod(fs, cg)),
                  (int)fs->fs_cgsize, NOCRED, &bp);
          if (error) {
                  brelse(bp);
                  return (error);
          }
          cgp = (struct cg *)bp->b_data;
          if (!cg_chkmagic(cgp, needswap)) {
                  brelse(bp);
                  return (0);
          }
          cgp->cg_old_time = ufs_rw32(time.tv_sec, needswap);
          if ((fs->fs_magic != FS_UFS1_MAGIC) ||
              (fs->fs_old_flags & FS_FLAGS_UPDATED))
                  cgp->cg_time = ufs_rw64(time.tv_sec, needswap);
          inosused = cg_inosused(cgp, needswap);
          ino %= fs->fs_ipg;
          if (isclr(inosused, ino)) {
                  printf("dev = 0x%x, ino = %d, fs = %s\n",
                      pip->i_dev, ino, fs->fs_fsmnt);
                  if (fs->fs_ronly == 0)
                          panic("ifree: freeing free inode");
          }
          clrbit(inosused, ino);
          if (ino < ufs_rw32(cgp->cg_irotor, needswap))
                  cgp->cg_irotor = ufs_rw32(ino, needswap);
          ufs_add32(cgp->cg_cs.cs_nifree, 1, needswap);
          fs->fs_cstotal.cs_nifree++;
          fs->fs_cs(fs, cg).cs_nifree++;
          if ((ap->a_mode & IFMT) == IFDIR) {
                  ufs_add32(cgp->cg_cs.cs_ndir, -1, needswap);
                  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 int32_t
  ffs_mapsearch(fs, cgp, bpref, allocsiz)
          struct fs *fs;
          struct cg *cgp;
          daddr_t bpref;
          int allocsiz;
  {
          int32_t bno;
          int start, len, loc, i;
          int blk, field, subfield, pos;
          int ostart, olen;
          u_int8_t *blksfree;
  #ifdef FFS_EI
          const int needswap = UFS_FSNEEDSWAP(fs);
  #endif
  
          /*
           * find the fragment by searching through the free block
           * map for an appropriate bit pattern
           */
          if (bpref)
                  start = dtogd(fs, bpref) / NBBY;
          else
                  start = ufs_rw32(cgp->cg_frotor, needswap) / NBBY;
          blksfree = cg_blksfree(cgp, needswap);
          len = howmany(fs->fs_fpg, NBBY) - start;
          ostart = start;
          olen = len;
          loc = scanc((u_int)len,
                  (const u_char *)&blksfree[start],
                  (const u_char *)fragtbl[fs->fs_frag],
                  (1 << (allocsiz - 1 + (fs->fs_frag & (NBBY - 1)))));
          if (loc == 0) {
                  len = start + 1;
                  start = 0;
                  loc = scanc((u_int)len,
                          (const u_char *)&blksfree[0],
                          (const u_char *)fragtbl[fs->fs_frag],
                          (1 << (allocsiz - 1 + (fs->fs_frag & (NBBY - 1)))));
                  if (loc == 0) {
                          printf("start = %d, len = %d, fs = %s\n",
                              ostart, olen, fs->fs_fsmnt);
                          printf("offset=%d %ld\n",
                                  ufs_rw32(cgp->cg_freeoff, needswap),
                                  (long)blksfree - (long)cgp);
                          printf("cg %d\n", cgp->cg_cgx);
                          panic("ffs_alloccg: map corrupted");
                          /* NOTREACHED */
                  }
          }
          bno = (start + len - loc) * NBBY;
          cgp->cg_frotor = ufs_rw32(bno, needswap);
          /*
           * 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;
                  }
          }
          printf("bno = %d, fs = %s\n", 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(fs, cgp, blkno, cnt)
          struct fs *fs;
          struct cg *cgp;
          int32_t blkno;
          int cnt;
  {
          int32_t *sump;
          int32_t *lp;
          u_char *freemapp, *mapp;
          int i, start, end, forw, back, map, bit;
  #ifdef FFS_EI
          const int needswap = UFS_FSNEEDSWAP(fs);
  #endif
  
          if (fs->fs_contigsumsize <= 0)
                  return;
          freemapp = cg_clustersfree(cgp, needswap);
          sump = cg_clustersum(cgp, needswap);
          /*
           * 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 >= ufs_rw32(cgp->cg_nclusterblks, needswap))
                  end = ufs_rw32(cgp->cg_nclusterblks, needswap);
          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;
          ufs_add32(sump[i], cnt, needswap);
          if (back > 0)
                  ufs_add32(sump[back], -cnt, needswap);
          if (forw > 0)
                  ufs_add32(sump[forw], -cnt, needswap);
  
          /*
           * Update cluster summary information.
           */
          lp = &sump[fs->fs_contigsumsize];
          for (i = fs->fs_contigsumsize; i > 0; i--)
                  if (ufs_rw32(*lp--, needswap) > 0)
                          break;
          fs->fs_maxcluster[ufs_rw32(cgp->cg_cgx, needswap)] = i;
  }
  
  /*
   * Fserr prints the name of a file system with an error diagnostic.
   * 
   * The form of the error message is:
   *      fs: error message
   */
  static void
  ffs_fserr(fs, uid, cp)
          struct fs *fs;
          u_int uid;
          char *cp;
  {
  
          log(LOG_ERR, "uid %d, pid %d, command %s, on %s: %s\n",
              uid, curproc->p_pid, curproc->p_comm, fs->fs_fsmnt, cp);
  }

Cache object: 7c6f383363372b3d46f8f3a7cad06acd