static int virtualblocks(struct fs *super, union dinode *dp)
{
	off_t nblk, sz;

	sz = DIP(super, dp, di_size);
#ifdef	COMPAT
	if (lblkno(super,sz) >= NDADDR) {
		nblk = blkroundup(super,sz);
		if (sz == nblk)
			nblk += super->fs_bsize;
	}

	return sz / 1024;

#else	/* COMPAT */

	if (lblkno(super,sz) >= NDADDR) {
		nblk = blkroundup(super,sz);
		sz = lblkno(super,nblk);
		sz = (sz - NDADDR + NINDIR(super) - 1) / NINDIR(super);
		while (sz > 0) {
			nblk += sz * super->fs_bsize;
			/* sz - 1 rounded up */
			sz = (sz - 1 + NINDIR(super) - 1) / NINDIR(super);
		}
	} else
		nblk = fragroundup(super,sz);

	return nblk / 512;
#endif	/* COMPAT */
}

/*
 * Read indirect blocks, and pass the data blocks to be dumped.
 */
static void
dmpindir(ino_t ino, daddr_t  blk, int ind_level, off_t *size)
{
	int i, cnt;
	char idblk[MAXBSIZE];

	if (blk != 0)
		bread(fsbtodb(sblock, blk), idblk, (int) sblock->fs_bsize);
	else
		memset(idblk, 0, (int)sblock->fs_bsize);
	if (ind_level <= 0) {
		if (*size < NINDIR(sblock) * sblock->fs_bsize)
			cnt = howmany(*size, sblock->fs_fsize);
		else
			cnt = NINDIR(sblock) * sblock->fs_frag;
		*size -= NINDIR(sblock) * sblock->fs_bsize;
		if (sblock->fs_magic == FS_UFS1_MAGIC)
			ufs1_blksout((int32_t *)idblk, cnt, ino);
		else
			ufs2_blksout((int64_t *)idblk, cnt, ino);
		return;
	}
	ind_level--;
	for (i = 0; i < NINDIR(sblock); i++) {
		if (sblock->fs_magic == FS_UFS1_MAGIC)
			dmpindir(ino, ((int32_t *)idblk)[i], ind_level,
			    size);
		else
			dmpindir(ino, ((int64_t *)idblk)[i], ind_level,
			    size);
		if (*size <= 0)
			return;
	}
}

/*
 * Read indirect blocks, and pass the data blocks to be dumped.
 */
static void
dmpindir(ufs1_ino_t ino, daddr_t blk, int ind_level, fsizeT *size)
{
	int i, cnt;
	daddr_t idblk[MAXNINDIR];

	if (blk != 0)
		bread(fsbtodb(sblock, blk), (char *)idblk, (int) sblock->fs_bsize);
	else
		memset(idblk, 0, (int)sblock->fs_bsize);
	if (ind_level <= 0) {
		if (*size < NINDIR(sblock) * sblock->fs_bsize)
			cnt = howmany(*size, sblock->fs_fsize);
		else
			cnt = NINDIR(sblock) * sblock->fs_frag;
		*size -= NINDIR(sblock) * sblock->fs_bsize;
		blksout(&idblk[0], cnt, ino);
		return;
	}
	ind_level--;
	for (i = 0; i < NINDIR(sblock); i++) {
		dmpindir(ino, idblk[i], ind_level, size);
		if (*size <= 0)
			return;
	}
}

/*
 * Read indirect blocks, and pass the data blocks to be searched
 * as directories. Quit as soon as any entry is found that will
 * require the directory to be dumped.
 */
static int
dirindir(ino_t ino, daddr64_t blkno, int ind_level, off_t *filesize)
{
	int ret = 0;
	int i;
	char idblk[MAXBSIZE];

	bread(fsbtodb(sblock, blkno), idblk, (int)sblock->fs_bsize);
	if (ind_level <= 0) {
		for (i = 0; *filesize > 0 && i < NINDIR(sblock); i++) {
			if (sblock->fs_magic == FS_UFS1_MAGIC)
				blkno = ((int32_t *)idblk)[i];
			else
				blkno = ((int64_t *)idblk)[i];
			if (blkno != 0)
				ret |= searchdir(ino, blkno, sblock->fs_bsize,
					*filesize);
			if (ret & HASDUMPEDFILE)
				*filesize = 0;
			else
				*filesize -= sblock->fs_bsize;
		}
		return (ret);
	}
	ind_level--;
	for (i = 0; *filesize > 0 && i < NINDIR(sblock); i++) {
		if (sblock->fs_magic == FS_UFS1_MAGIC)
			blkno = ((int32_t *)idblk)[i];
		else
			blkno = ((int64_t *)idblk)[i];
		if (blkno != 0)
			ret |= dirindir(ino, blkno, ind_level, filesize);
	}
	return (ret);
}

/*
 * Read indirect blocks, and pass the data blocks to be searched
 * as directories. Quit as soon as any entry is found that will
 * require the directory to be dumped.
 */
static int
dirindir(ufs1_ino_t ino, daddr_t blkno, int ind_level, long *filesize,
         long *tape_size, int nodump)
{
	int ret = 0;
	int i;
	daddr_t	idblk[MAXNINDIR];

	bread(fsbtodb(sblock, blkno), (char *)idblk, (int)sblock->fs_bsize);
	if (ind_level <= 0) {
		for (i = 0; *filesize > 0 && i < NINDIR(sblock); i++) {
			blkno = idblk[i];
			if (blkno != 0) {
				ret |= searchdir(ino, blkno, sblock->fs_bsize,
					*filesize, tape_size, nodump);
			}
			if (ret & HASDUMPEDFILE)
				*filesize = 0;
			else
				*filesize -= sblock->fs_bsize;
		}
		return (ret);
	}
	ind_level--;
	for (i = 0; *filesize > 0 && i < NINDIR(sblock); i++) {
		blkno = idblk[i];
		if (blkno != 0) {
			ret |= dirindir(ino, blkno, ind_level, filesize,
			    tape_size, nodump);
		}
	}
	return (ret);
}

/*
 * Create the root directory for this file system and the lost+found
 * directory.
 */
static void
make_dinode(ino_t ino, struct ufs1_dinode *dip, int nfrags, struct lfs *fs)
{
	int fsb_per_blk, i;
	int nblocks, bb, base, factor, lvl;

	nblocks = howmany(nfrags, fs->lfs_frag);
	if(nblocks >= NDADDR)
		nfrags = roundup(nfrags, fs->lfs_frag);

	dip->di_nlink = 1;
	dip->di_blocks = fragstofsb(fs, nfrags);

	dip->di_size = (nfrags << fs->lfs_ffshift);
	dip->di_atime = dip->di_mtime = dip->di_ctime = fs->lfs_tstamp;
	dip->di_atimensec = dip->di_mtimensec = dip->di_ctimensec = 0;
	dip->di_inumber = ino;
	dip->di_gen = 1;

	fsb_per_blk = fragstofsb(fs, blkstofrags(fs, 1));

	if (NDADDR < nblocks) {
		/* Count up how many indirect blocks we need, recursively */
		/* XXX We are only called with nblocks > 1 for Ifile */
		bb = nblocks - NDADDR;
		while (bb > 0) {
			bb = howmany(bb, NINDIR(fs));
			ifibc += bb;
			--bb;
		}
		dip->di_blocks += fragstofsb(fs, blkstofrags(fs, ifibc));
	}

	/* Assign the block addresses for the ifile */
	for (i = 0; i < MIN(nblocks,NDADDR); i++) {
		dip->di_db[i] = 0x0;
	}
	if(nblocks > NDADDR) {
		dip->di_ib[0] = 0x0;
		bb = howmany(nblocks - NDADDR, NINDIR(fs)) - 1;
		factor = NINDIR(fs);
		base = -NDADDR - factor;
		lvl = 1;
		while (bb > 0) {
			dip->di_ib[lvl] = 0x0;
			bb = howmany(bb, NINDIR(fs));
			--bb;
			factor *= NINDIR(fs);
			base -= factor;
			++lvl;
		}
	}
}

/*
 * Read indirect blocks, and pass the data blocks to be searched
 * as directories. Quit as soon as any entry is found that will
 * require the directory to be dumped.
 */
static int
dirindir(
	ino_t ino,
	ufs2_daddr_t blkno,
	int ind_level,
	long *filesize,
	long *tapesize,
	int nodump,
	ino_t maxino)
{
	union {
		ufs1_daddr_t ufs1[MAXBSIZE / sizeof(ufs1_daddr_t)];
		ufs2_daddr_t ufs2[MAXBSIZE / sizeof(ufs2_daddr_t)];
	} idblk;
	int ret = 0;
	int i;

	bread(fsbtodb(sblock, blkno), (char *)&idblk, (int)sblock->fs_bsize);
	if (ind_level <= 0) {
		for (i = 0; *filesize > 0 && i < NINDIR(sblock); i++) {
			if (sblock->fs_magic == FS_UFS1_MAGIC)
				blkno = idblk.ufs1[i];
			else
				blkno = idblk.ufs2[i];
			if (blkno != 0)
				ret |= searchdir(ino, blkno, sblock->fs_bsize,
					*filesize, tapesize, nodump, maxino);
			if (ret & HASDUMPEDFILE)
				*filesize = 0;
			else
				*filesize -= sblock->fs_bsize;
		}
		return (ret);
	}
	ind_level--;
	for (i = 0; *filesize > 0 && i < NINDIR(sblock); i++) {
		if (sblock->fs_magic == FS_UFS1_MAGIC)
			blkno = idblk.ufs1[i];
		else
			blkno = idblk.ufs2[i];
		if (blkno != 0)
			ret |= dirindir(ino, blkno, ind_level, filesize,
			    tapesize, nodump, maxino);
	}
	return (ret);
}

static grub_int64_t
block_map (int file_block)
{
  int bnum, offset, bsize;
  
  if (file_block < NDADDR)
    return (INODE_UFS2->di_db[file_block]);
  
  /* If the blockmap loaded does not include FILE_BLOCK,
     load a new blockmap.  */

  if ((bnum = fsbtodb (SUPERBLOCK, INODE_UFS2->di_ib[0])) != mapblock
      || (mapblock_offset <= bnum && bnum <= mapblock_offset + mapblock_bsize))
    {
      if (MAPBUF_LEN < SUPERBLOCK->fs_bsize)
	{
	  offset = ((file_block - NDADDR) % NINDIR (SUPERBLOCK));
	  bsize = MAPBUF_LEN;
	  
	  if (offset + MAPBUF_LEN > SUPERBLOCK->fs_bsize)
	    offset = (SUPERBLOCK->fs_bsize - MAPBUF_LEN) / sizeof (int);
	}
      else
	{
	  bsize = SUPERBLOCK->fs_bsize;
	  offset = 0;
	}
      
      if (! devread (bnum, offset * sizeof (int), bsize, (char *) MAPBUF, 0xedde0d90))
	{
	  mapblock = -1;
	  mapblock_bsize = -1;
	  mapblock_offset = -1;
	  errnum = ERR_FSYS_CORRUPT;
	  return -1;
	}
      
      mapblock = bnum;
      mapblock_bsize = bsize;
      mapblock_offset = offset;
    }
  
  return (((grub_int64_t *) MAPBUF)[((file_block - NDADDR) % NINDIR (SUPERBLOCK))
				    - mapblock_offset]);
}

static int
block_map(int file_block)
{
	int bnum;
	if (file_block < NDADDR)
		return(inode.i_db[file_block]);
	if ((bnum=fsbtodb(fs, inode.i_ib[0])+boff) != mapblock) {
		devread(mapbuf, bnum, fs->fs_bsize);
		mapblock = bnum;
	}
	return (((int *)mapbuf)[(file_block - NDADDR) % NINDIR(fs)]);
}

/*
 * Recursively print a list of indirect blocks.
 */
static void
printindir(ufs2_daddr_t blk, int level, char *bufp)
{
    struct bufarea buf, *bp;
    char tempbuf[32];		/* enough to print an ufs2_daddr_t */
    int i, j, cpl, charssofar;
    ufs2_daddr_t blkno;

    if (blk == 0)
	return;
    printf("%jd (%d) =>\n", (intmax_t)blk, level);
    if (level == 0) {
	/* for the final indirect level, don't use the cache */
	bp = &buf;
	bp->b_un.b_buf = bufp;
	bp->b_prev = bp->b_next = bp;
	initbarea(bp);

	getblk(bp, blk, sblock.fs_bsize);
    } else
	bp = getdatablk(blk, sblock.fs_bsize);

    cpl = charsperline();
    for (i = charssofar = 0; i < NINDIR(&sblock); i++) {
	if (sblock.fs_magic == FS_UFS1_MAGIC)
		blkno = bp->b_un.b_indir1[i];
	else
		blkno = bp->b_un.b_indir2[i];
	if (blkno == 0)
	    continue;
	j = sprintf(tempbuf, "%jd", (intmax_t)blkno);
	if (level == 0) {
	    charssofar += j;
	    if (charssofar >= cpl - 2) {
		putchar('\n');
		charssofar = j;
	    }
	}
	fputs(tempbuf, stdout);
	if (level == 0) {
	    printf(", ");
	    charssofar += 2;
	} else {
	    printf(" =>\n");
	    printindir(blkno, level - 1, bufp);
	    printf("\n");
	    charssofar = 0;
	}
    }
    if (level == 0)
	putchar('\n');
    return;
}

/*
 * Read indirect blocks, and pass the data blocks to be dumped.
 */
static void
dmpindir(union dinode *dp, ino_t ino, ufs2_daddr_t blk, int ind_level,
	off_t *size)
{
	union {
		ufs1_daddr_t ufs1[MAXBSIZE / sizeof(ufs1_daddr_t)];
		ufs2_daddr_t ufs2[MAXBSIZE / sizeof(ufs2_daddr_t)];
	} idblk;
	int i, cnt, last;

	if (blk != 0)
		bread(fsbtodb(sblock, blk), (char *)&idblk,
		    (int)sblock->fs_bsize);
	else
		memset(&idblk, 0, sblock->fs_bsize);
	if (ind_level <= 0) {
		if (*size > NINDIR(sblock) * sblock->fs_bsize) {
			cnt = NINDIR(sblock) * sblock->fs_frag;
			last = 0;
		} else {
			cnt = howmany(*size, sblock->fs_fsize);
			last = 1;
		}
		*size -= NINDIR(sblock) * sblock->fs_bsize;
		if (sblock->fs_magic == FS_UFS1_MAGIC)
			ufs1_blksout(idblk.ufs1, cnt, ino);
		else
			ufs2_blksout(dp, idblk.ufs2, cnt, ino, last);
		return;
	}
	ind_level--;
	for (i = 0; i < NINDIR(sblock); i++) {
		if (sblock->fs_magic == FS_UFS1_MAGIC)
			dmpindir(dp, ino, idblk.ufs1[i], ind_level, size);
		else
			dmpindir(dp, ino, idblk.ufs2[i], ind_level, size);
		if (*size <= 0)
			return;
	}
}

int
block_map(int file_block)
{
	if (file_block < NDADDR)
		return(inode.i_db[file_block]);
	if ((bnum=fsbtodb(fs, inode.i_ib[0])+boff) != mapblock) {
		cnt = fs->fs_bsize;
		if (disk_read(bnum, cnt, (vm_offset_t)mapbuf))
			return(-1);
		mapblock = bnum;
	}
	return (((int *)mapbuf)[(file_block - NDADDR) % NINDIR(fs)]);
}

/*
 * Recursively print a list of indirect blocks.
 */
static int
printindir(ufs_daddr_t blk, int level, char *bufp)
{
    struct bufarea buf, *bp;
    char tempbuf[32];		/* enough to print an ufs_daddr_t */
    int i, j, cpl, charssofar;
    ufs_daddr_t blkno;

    if (level == 0) {
	/* for the final indirect level, don't use the cache */
	bp = &buf;
	bp->b_un.b_buf = bufp;
	bp->b_prev = bp->b_next = bp;
	initbarea(bp);

	getblk(bp, blk, sblock.fs_bsize);
    } else
	bp = getdatablk(blk, sblock.fs_bsize);

    cpl = charsperline();
    for (i = charssofar = 0; i < NINDIR(&sblock); i++) {
	blkno = bp->b_un.b_indir[i];
	if (blkno == 0) {
	    if (level == 0)
		putchar('\n');
	    return 0;
	}
	j = sprintf(tempbuf, "%d", blkno);
	if (level == 0) {
	    charssofar += j;
	    if (charssofar >= cpl - 2) {
		putchar('\n');
		charssofar = j;
	    }
	}
	fputs(tempbuf, stdout);
	if (level == 0) {
	    printf(", ");
	    charssofar += 2;
	} else {
	    printf(" =>\n");
	    if (printindir(blkno, level - 1, bufp) == 0)
		return 0;
	}
    }
    if (level == 0)
	putchar('\n');
    return 1;
}

diskaddr_t
bmap(diskaddr_t i)
{
	daddr32_t ibuf[MAXNINDIR];

	if (i < NDADDR)
		return ((diskaddr_t)gip->di_db[i]);
	i -= NDADDR;
	if (i > NINDIR(&sblock)) {
		(void) fprintf(stderr, "ff    : %lu - huge directory\n", ino);
		return ((diskaddr_t)0);
	}
	bread(fsbtodb(&sblock, gip->di_ib[0]), (char *)ibuf, sizeof (ibuf));
	return ((diskaddr_t)ibuf[i]);
}

/*
 * Truncate a directory to its first hole.  If there are non-holes
 * in the direct blocks after the problem block, move them down so
 * that there's somewhat less lossage.  Doing this for indirect blocks
 * is left as an exercise for the reader.
 */
static void
collapse_dirhole(fsck_ino_t inumber, struct inodesc *idesc)
{
	offset_t new_size;
	int blocks;

	if (idesc->id_firsthole < 0) {
		return;
	}

	/*
	 * Since truncino() adjusts the size, we don't need to do that here,
	 * but we have to tell it what final size we want.
	 *
	 * We need to count from block zero up through the last block
	 * before the hole.  If the hole is in the indirect blocks, chop at
	 * the start of the nearest level of indirection.  Orphans will
	 * get reconnected, so we're not actually losing anything by doing
	 * it this way, and we're simplifying truncation significantly.
	 */
	new_size = idesc->id_firsthole * (offset_t)sblock.fs_bsize;
	blocks = howmany(new_size, sblock.fs_bsize);
	if (blocks > NDADDR) {
		if (blocks < (NDADDR + NINDIR(&sblock)))
			blocks = NDADDR;
		else if (blocks < (NDADDR + NINDIR(&sblock) +
		    (NINDIR(&sblock) * NINDIR(&sblock))))
			blocks = NDADDR + NINDIR(&sblock);
		else
			blocks = NDADDR + NINDIR(&sblock) +
			    (NINDIR(&sblock) * NINDIR(&sblock));
		new_size = blocks * sblock.fs_bsize;
		if (debug)
			(void) printf("to %lld (blocks %d)\n",
			    (longlong_t)new_size, blocks);
	}
	truncino(inumber, new_size, TI_NOPARENT);

	/*
	 * Technically, there are still the original number of fragments
	 * associated with the object.  However, that number is not used
	 * to control anything, so we can do the in-memory truncation of
	 * it without bad things happening.
	 */
	idesc->id_entryno = btodb(new_size);
}

//.........这里部分代码省略.........
		sblock.fs_inopb = sblock.fs_bsize / sizeof(struct ufs1_dinode);
		sblock.fs_maxsymlinklen = ((NDADDR + NIADDR) *
		    sizeof (ufs1_daddr_t));
		sblock.fs_old_inodefmt = FS_44INODEFMT;
		sblock.fs_old_cgoffset = 0;
		sblock.fs_old_cgmask = 0xffffffff;
		sblock.fs_old_size = sblock.fs_size;
		sblock.fs_old_rotdelay = 0;
		sblock.fs_old_rps = 60;
		sblock.fs_old_nspf = sblock.fs_fsize / sectorsize;
		sblock.fs_old_cpg = 1;
		sblock.fs_old_interleave = 1;
		sblock.fs_old_trackskew = 0;
		sblock.fs_old_cpc = 0;
		sblock.fs_old_postblformat = 1;
		sblock.fs_old_nrpos = 1;
	} else {
		sblock.fs_magic = FS_UFS2_MAGIC;
		sblock.fs_sblockloc = SBLOCK_UFS2;
		sblock.fs_nindir = sblock.fs_bsize / sizeof(ufs2_daddr_t);
		sblock.fs_inopb = sblock.fs_bsize / sizeof(struct ufs2_dinode);
		sblock.fs_maxsymlinklen = ((NDADDR + NIADDR) *
		    sizeof (ufs2_daddr_t));
	}

	sblock.fs_sblkno =
	    roundup(howmany(sblock.fs_sblockloc + SBLOCKSIZE, sblock.fs_fsize),
		sblock.fs_frag);
	sblock.fs_cblkno = (daddr_t)(sblock.fs_sblkno +
	    roundup(howmany(SBLOCKSIZE, sblock.fs_fsize), sblock.fs_frag));
	sblock.fs_iblkno = sblock.fs_cblkno + sblock.fs_frag;
	sblock.fs_maxfilesize = sblock.fs_bsize * NDADDR - 1;
	for (sizepb = sblock.fs_bsize, i = 0; i < NIADDR; i++) {
		sizepb *= NINDIR(&sblock);
		sblock.fs_maxfilesize += sizepb;
	}

	/*
	 * Calculate the number of blocks to put into each cylinder group.
	 *
	 * This algorithm selects the number of blocks per cylinder
	 * group. The first goal is to have at least enough data blocks
	 * in each cylinder group to meet the density requirement. Once
	 * this goal is achieved we try to expand to have at least
	 * 1 cylinder group. Once this goal is achieved, we pack as
	 * many blocks into each cylinder group map as will fit.
	 *
	 * We start by calculating the smallest number of blocks that we
	 * can put into each cylinder group. If this is too big, we reduce
	 * the density until it fits.
	 */
	origdensity = density;
	for (;;) {
		fragsperinode = MAX(numfrags(&sblock, density), 1);
		minfpg = fragsperinode * INOPB(&sblock);
		if (minfpg > sblock.fs_size)
			minfpg = sblock.fs_size;
		sblock.fs_ipg = INOPB(&sblock);
		sblock.fs_fpg = roundup(sblock.fs_iblkno +
		    sblock.fs_ipg / INOPF(&sblock), sblock.fs_frag);
		if (sblock.fs_fpg < minfpg)
			sblock.fs_fpg = minfpg;
		sblock.fs_ipg = roundup(howmany(sblock.fs_fpg, fragsperinode),
		    INOPB(&sblock));
		sblock.fs_fpg = roundup(sblock.fs_iblkno +
		    sblock.fs_ipg / INOPF(&sblock), sblock.fs_frag);

static daddr_t
sbmap(struct iob *io, daddr_t bn)
{
	register struct inode *ip;
	int i, j, sh;
	daddr_t nb, *bap;

	ip = &io->i_ino;

	if (ip->i_icflags & IC_FASTLINK)
	{
		error("fast symlinks unimplemented\n");
		return ((daddr_t)0);
	}

	if (bn < 0) {
#if	SYS_MESSAGES
		error("bn negative\n");
#endif
		return ((daddr_t)0);
	}

	/*
	 * blocks 0..NDADDR are direct blocks
	 */
	if(bn < NDADDR)
	{
		nb = ip->i_db[bn];
		return (nb);
	}

	/*
	 * addresses NIADDR have single and double indirect blocks.
	 * the first step is to determine how many levels of indirection.
	 */
	sh = 1;
	bn -= NDADDR;
	for (j = NIADDR; j > 0; j--) {
		sh *= NINDIR(io->i_fs);
		if (bn < sh)
			break;
		bn -= sh;
	}
	if (j == 0) {
#if	SYS_MESSAGES
		error("bn ovf %d\n", bn);
#endif
		return ((daddr_t)0);
	}

	/*
	 * fetch the first indirect block address from the inode
	 */
	nb = ip->i_ib[NIADDR - j];
	if (nb == 0) {
#if	SYS_MESSAGES
		error("bn void %d\n",bn);
#endif
		return ((daddr_t)0);
	}

	/*
	 * fetch through the indirect blocks
	 */
	for (; j <= NIADDR; j++) {
		if (blknos[j] != nb) {
			io->i_bn = fsbtodb(io->i_fs, nb) + io->i_boff;
			if (b[j] == (char *)0)
				b[j] = malloc(MAXBSIZE);
			io->i_ma = b[j];
			io->i_cc = io->i_fs->fs_bsize;
			if (devread(io) != io->i_fs->fs_bsize) {
#if	SYS_MESSAGES
				error("bn %d: read error\n", io->i_bn);
#endif
				return ((daddr_t)0);
			}
			blknos[j] = nb;
		}
		bap = (daddr_t *)b[j];
		sh /= NINDIR(io->i_fs);
		i = (bn / sh) % NINDIR(io->i_fs);
#if	BIG_ENDIAN_FS
#if 1
		// for now it is little endian FS for intel
		nb = bap[i];
#else
		nb = OSSwapBigToHostInt32(bap[i]);
#endif 1
#else	BIG_ENDIAN_FS
		nb = bap[i];
#endif	BIG_ENDIAN_FS
		if(nb == 0) {
#if	SYS_MESSAGES
			error("bn void %d\n",bn);
#endif
			return ((daddr_t)0);
		}
	}

//.........这里部分代码省略.........

/*
 * Release blocks associated with the inode ip and stored in the indirect
 * block bn.  Blocks are free'd in LIFO order up to (but not including)
 * lastbn.  If level is greater than SINGLE, the block is an indirect block
 * and recursive calls to indirtrunc must be used to cleanse other indirect
 * blocks.
 *
 * NB: triple indirect blocks are untested.
 */
static int
ffs_indirtrunc(struct inode *ip, ufs_daddr_t lbn, ufs_daddr_t dbn,
	       ufs_daddr_t lastbn, int level, long *countp)
{
	int i;
	struct buf *bp;
	struct fs *fs = ip->i_fs;
	ufs_daddr_t *bap;
	struct vnode *vp;
	ufs_daddr_t *copy = NULL, nb, nlbn, last;
	long blkcount, factor;
	int nblocks, blocksreleased = 0;
	int error = 0, allerror = 0;

	/*
	 * Calculate index in current block of last
	 * block to be kept.  -1 indicates the entire
	 * block so we need not calculate the index.
	 */
	factor = 1;
	for (i = SINGLE; i < level; i++)
		factor *= NINDIR(fs);
	last = lastbn;
	if (lastbn > 0)
		last /= factor;
	nblocks = btodb(fs->fs_bsize);
	/*
	 * Get buffer of block pointers, zero those entries corresponding
	 * to blocks to be free'd, and update on disk copy first.  Since
	 * double(triple) indirect before single(double) indirect, calls
	 * to bmap on these blocks will fail.  However, we already have
	 * the on disk address, so we have to set the bio_offset field
	 * explicitly instead of letting bread do everything for us.
	 */
	vp = ITOV(ip);
	bp = getblk(vp, lblktodoff(fs, lbn), (int)fs->fs_bsize, 0, 0);
	if ((bp->b_flags & B_CACHE) == 0) {
		bp->b_flags &= ~(B_ERROR|B_INVAL);
		bp->b_cmd = BUF_CMD_READ;
		if (bp->b_bcount > bp->b_bufsize)
			panic("ffs_indirtrunc: bad buffer size");
		/*
		 * BIO is bio2 which chains back to bio1.  We wait
		 * on bio1.
		 */
		bp->b_bio2.bio_offset = dbtodoff(fs, dbn);
		bp->b_bio1.bio_done = biodone_sync;
		bp->b_bio1.bio_flags |= BIO_SYNC;
		vfs_busy_pages(vp, bp);
		/*
		 * Access the block device layer using the device vnode
		 * and the translated block number (bio2) instead of the
		 * file vnode (vp) and logical block number (bio1).
		 *
		 * Even though we are bypassing the vnode layer, we still
		 * want the vnode state to indicate that an I/O on its behalf
		 * is in progress.
		 */
		bio_start_transaction(&bp->b_bio1, &vp->v_track_read);
		vn_strategy(ip->i_devvp, &bp->b_bio2);
		error = biowait(&bp->b_bio1, "biord");
	}
	if (error) {
		brelse(bp);
		*countp = 0;
		return (error);
	}

	bap = (ufs_daddr_t *)bp->b_data;
	if (lastbn != -1) {
		copy = kmalloc(fs->fs_bsize, M_TEMP, M_WAITOK);
		bcopy((caddr_t)bap, (caddr_t)copy, (uint)fs->fs_bsize);
		bzero((caddr_t)&bap[last + 1],
		    (uint)(NINDIR(fs) - (last + 1)) * sizeof (ufs_daddr_t));
		if (DOINGASYNC(vp)) {
			bawrite(bp);
		} else {
			error = bwrite(bp);
			if (error)
				allerror = error;
		}
		bap = copy;
	}

	/*
	 * Recursively free totally unused blocks.
	 */
	for (i = NINDIR(fs) - 1, nlbn = lbn + 1 - i * factor; i > last;
	    i--, nlbn += factor) {
		nb = bap[i];
		if (nb == 0)
//.........这里部分代码省略.........

//.........这里部分代码省略.........
		    fragroundup(fs, blkoff(fs, length)) < fs->fs_bsize) {
			bundirty(bp);
			error = VOP_FSYNC(ovp, MNT_WAIT, 0);
			if (error) {
				bdwrite(bp);
				return (error);
			}
		}
		oip->i_size = length;
		size = blksize(fs, oip, lbn);
#if 0
		/* remove - nvtruncbuf deals with this */
		if (ovp->v_type != VDIR)
			bzero((char *)bp->b_data + offset,
			    (uint)(size - offset));
#endif
		/* Kirk's code has reallocbuf(bp, size, 1) here */
		allocbuf(bp, size);
		if (bp->b_bufsize == fs->fs_bsize)
			bp->b_flags |= B_CLUSTEROK;
		if (aflags & B_SYNC)
			bwrite(bp);
		else
			bawrite(bp);
	}
	/*
	 * Calculate index into inode's block list of
	 * last direct and indirect blocks (if any)
	 * which we want to keep.  Lastblock is -1 when
	 * the file is truncated to 0.
	 */
	lastblock = lblkno(fs, length + fs->fs_bsize - 1) - 1;
	lastiblock[SINGLE] = lastblock - NDADDR;
	lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
	lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs);
	nblocks = btodb(fs->fs_bsize);

	/*
	 * Update file and block pointers on disk before we start freeing
	 * blocks.  If we crash before free'ing blocks below, the blocks
	 * will be returned to the free list.  lastiblock values are also
	 * normalized to -1 for calls to ffs_indirtrunc below.
	 */
	bcopy((caddr_t)&oip->i_db[0], (caddr_t)oldblks, sizeof oldblks);
	for (level = TRIPLE; level >= SINGLE; level--)
		if (lastiblock[level] < 0) {
			oip->i_ib[level] = 0;
			lastiblock[level] = -1;
		}
	for (i = NDADDR - 1; i > lastblock; i--)
		oip->i_db[i] = 0;
	oip->i_flag |= IN_CHANGE | IN_UPDATE;
	error = ffs_update(ovp, 1);
	if (error && allerror == 0)
		allerror = error;
	
	/*
	 * Having written the new inode to disk, save its new configuration
	 * and put back the old block pointers long enough to process them.
	 * Note that we save the new block configuration so we can check it
	 * when we are done.
	 */
	bcopy((caddr_t)&oip->i_db[0], (caddr_t)newblks, sizeof newblks);
	bcopy((caddr_t)oldblks, (caddr_t)&oip->i_db[0], sizeof oldblks);
	oip->i_size = osize;

//.........这里部分代码省略.........
	sblock.fs_bsize = bsize;
	sblock.fs_fsize = fsize;
	if (!POWEROF2(sblock.fs_bsize)) {
		printf("block size must be a power of 2, not %d\n",
		    sblock.fs_bsize);
		exit(16);
	}
	if (!POWEROF2(sblock.fs_fsize)) {
		printf("fragment size must be a power of 2, not %d\n",
		    sblock.fs_fsize);
		exit(17);
	}
	if (sblock.fs_fsize < sectorsize) {
		printf("fragment size %d is too small, minimum is %d\n",
		    sblock.fs_fsize, sectorsize);
		exit(18);
	}
	if (sblock.fs_bsize < MINBSIZE) {
		printf("block size %d is too small, minimum is %d\n",
		    sblock.fs_bsize, MINBSIZE);
		exit(19);
	}
	if (sblock.fs_bsize < sblock.fs_fsize) {
		printf("block size (%d) cannot be smaller than fragment size (%d)\n",
		    sblock.fs_bsize, sblock.fs_fsize);
		exit(20);
	}
	sblock.fs_bmask = ~(sblock.fs_bsize - 1);
	sblock.fs_fmask = ~(sblock.fs_fsize - 1);
	sblock.fs_qbmask = ~sblock.fs_bmask;
	sblock.fs_qfmask = ~sblock.fs_fmask;
	for (sblock.fs_bshift = 0, i = sblock.fs_bsize; i > 1; i >>= 1)
		sblock.fs_bshift++;
	for (sblock.fs_fshift = 0, i = sblock.fs_fsize; i > 1; i >>= 1)
		sblock.fs_fshift++;
	sblock.fs_frag = numfrags(&sblock, sblock.fs_bsize);
	for (sblock.fs_fragshift = 0, i = sblock.fs_frag; i > 1; i >>= 1)
		sblock.fs_fragshift++;
	if (sblock.fs_frag > MAXFRAG) {
		printf("fragment size %d is too small, minimum with block size %d is %d\n",
		    sblock.fs_fsize, sblock.fs_bsize,
		    sblock.fs_bsize / MAXFRAG);
		exit(21);
	}
	sblock.fs_nrpos = nrpos;
	sblock.fs_nindir = sblock.fs_bsize / sizeof(daddr_t);
	sblock.fs_inopb = sblock.fs_bsize / sizeof(struct ufs1_dinode);
	sblock.fs_nspf = sblock.fs_fsize / sectorsize;
	for (sblock.fs_fsbtodb = 0, i = NSPF(&sblock); i > 1; i >>= 1)
		sblock.fs_fsbtodb++;
	sblock.fs_sblkno =
	    roundup(howmany(bbsize + sbsize, sblock.fs_fsize), sblock.fs_frag);
	sblock.fs_cblkno = (daddr_t)(sblock.fs_sblkno +
	    roundup(howmany(sbsize, sblock.fs_fsize), sblock.fs_frag));
	sblock.fs_iblkno = sblock.fs_cblkno + sblock.fs_frag;
	sblock.fs_cgoffset = roundup(
	    howmany(sblock.fs_nsect, NSPF(&sblock)), sblock.fs_frag);
	for (sblock.fs_cgmask = 0xffffffff, i = sblock.fs_ntrak; i > 1; i >>= 1)
		sblock.fs_cgmask <<= 1;
	if (!POWEROF2(sblock.fs_ntrak))
		sblock.fs_cgmask <<= 1;
	sblock.fs_maxfilesize = sblock.fs_bsize * NDADDR - 1;
	for (sizepb = sblock.fs_bsize, i = 0; i < NIADDR; i++) {
		sizepb *= NINDIR(&sblock);
		sblock.fs_maxfilesize += sizepb;
	}
	/*
	 * Validate specified/determined secpercyl
	 * and calculate minimum cylinders per group.
	 */
	sblock.fs_spc = secpercyl;
	for (sblock.fs_cpc = NSPB(&sblock), i = sblock.fs_spc;
	     sblock.fs_cpc > 1 && (i & 1) == 0;
	     sblock.fs_cpc >>= 1, i >>= 1)
		/* void */;
	mincpc = sblock.fs_cpc;
	bpcg = sblock.fs_spc * sectorsize;
	inospercg = roundup(bpcg / sizeof(struct ufs1_dinode), INOPB(&sblock));
	if (inospercg > MAXIPG(&sblock))
		inospercg = MAXIPG(&sblock);
	used = (sblock.fs_iblkno + inospercg / INOPF(&sblock)) * NSPF(&sblock);
	mincpgcnt = howmany(sblock.fs_cgoffset * (~sblock.fs_cgmask) + used,
	    sblock.fs_spc);
	mincpg = roundup(mincpgcnt, mincpc);
	/*
	 * Ensure that cylinder group with mincpg has enough space
	 * for block maps.
	 */
	sblock.fs_cpg = mincpg;
	sblock.fs_ipg = inospercg;
	if (maxcontig > 1)
		sblock.fs_contigsumsize = MIN(maxcontig, FS_MAXCONTIG);
	mapcramped = 0;
	while (CGSIZE(&sblock) > (uint32_t)sblock.fs_bsize) {
		mapcramped = 1;
		if (sblock.fs_bsize < MAXBSIZE) {
			sblock.fs_bsize <<= 1;
			if ((i & 1) == 0) {
				i >>= 1;
			} else {