traverse.c

早期freebsd实现

		if (dp->d_ino == 0)
			continue;
		if (dp->d_name[0] == '.') {
			if (dp->d_name[1] == '\0')
				continue;
			if (dp->d_name[1] == '.' && dp->d_name[2] == '\0')
				continue;
		}
		if (TSTINO(dp->d_ino, dumpinomap)) {
			ret |= HASDUMPEDFILE;
			if (ret & HASSUBDIRS)
				break;
		}
		if (TSTINO(dp->d_ino, dumpdirmap)) {
			ret |= HASSUBDIRS;
			if (ret & HASDUMPEDFILE)
				break;
		}
	}
	return (ret);
}

/*
 * Dump passes 3 and 4.
 *
 * Dump the contents of an inode to tape.
 */
void
dumpino(dp, ino)
	register struct dinode *dp;
	ino_t ino;
{
	int ind_level, cnt;
	fsizeT size;
	char buf[TP_BSIZE];

	if (newtape) {
		newtape = 0;
		dumpmap(dumpinomap, TS_BITS, ino);
	}
	CLRINO(ino, dumpinomap);
	spcl.c_dinode = *dp;
	spcl.c_type = TS_INODE;
	spcl.c_count = 0;
	switch (dp->di_mode & S_IFMT) {

	case 0:
		/*
		 * Freed inode.
		 */
		return;

	case S_IFLNK:
		/*
		 * Check for short symbolic link.
		 */
#ifdef FS_44INODEFMT
		if (dp->di_size > 0 &&
		    dp->di_size < sblock->fs_maxsymlinklen) {
			spcl.c_addr[0] = 1;
			spcl.c_count = 1;
			writeheader(ino);
			bcopy((caddr_t)dp->di_shortlink, buf,
			    (u_long)dp->di_size);
			buf[dp->di_size] = '\0';
			writerec(buf, 0);
			return;
		}
#endif
		/* fall through */

	case S_IFDIR:
	case S_IFREG:
		if (dp->di_size > 0)
			break;
		/* fall through */

	case S_IFIFO:
	case S_IFSOCK:
	case S_IFCHR:
	case S_IFBLK:
		writeheader(ino);
		return;

	default:
		msg("Warning: undefined file type 0%o\n", dp->di_mode & IFMT);
		return;
	}
	if (dp->di_size > NDADDR * sblock->fs_bsize)
		cnt = NDADDR * sblock->fs_frag;
	else
		cnt = howmany(dp->di_size, sblock->fs_fsize);
	blksout(&dp->di_db[0], cnt, ino);
	if ((size = dp->di_size - NDADDR * sblock->fs_bsize) <= 0)
		return;
	for (ind_level = 0; ind_level < NIADDR; ind_level++) {
		dmpindir(ino, dp->di_ib[ind_level], ind_level, &size);
		if (size <= 0)
			return;
	}
}

/*
 * Read indirect blocks, and pass the data blocks to be dumped.
 */
static void
dmpindir(ino, blk, ind_level, size)
	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
		bzero((char *)idblk, (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;
	}
}

/*
 * Collect up the data into tape record sized buffers and output them.
 */
void
blksout(blkp, frags, ino)
	daddr_t *blkp;
	int frags;
	ino_t ino;
{
	register daddr_t *bp;
	int i, j, count, blks, tbperdb;

	blks = howmany(frags * sblock->fs_fsize, TP_BSIZE);
	tbperdb = sblock->fs_bsize >> tp_bshift;
	for (i = 0; i < blks; i += TP_NINDIR) {
		if (i + TP_NINDIR > blks)
			count = blks;
		else
			count = i + TP_NINDIR;
		for (j = i; j < count; j++)
			if (blkp[j / tbperdb] != 0)
				spcl.c_addr[j - i] = 1;
			else
				spcl.c_addr[j - i] = 0;
		spcl.c_count = count - i;
		writeheader(ino);
		bp = &blkp[i / tbperdb];
		for (j = i; j < count; j += tbperdb, bp++)
			if (*bp != 0)
				if (j + tbperdb <= count)
					dumpblock(*bp, (int)sblock->fs_bsize);
				else
					dumpblock(*bp, (count - j) * TP_BSIZE);
		spcl.c_type = TS_ADDR;
	}
}

/*
 * Dump a map to the tape.
 */
void
dumpmap(map, type, ino)
	char *map;
	int type;
	ino_t ino;
{
	register int i;
	char *cp;

	spcl.c_type = type;
	spcl.c_count = howmany(mapsize * sizeof(char), TP_BSIZE);
	writeheader(ino);
	for (i = 0, cp = map; i < spcl.c_count; i++, cp += TP_BSIZE)
		writerec(cp, 0);
}

/*
 * Write a header record to the dump tape.
 */
void
writeheader(ino)
	ino_t ino;
{
	register long sum, cnt, *lp;

	spcl.c_inumber = ino;
	spcl.c_magic = NFS_MAGIC;
	spcl.c_checksum = 0;
	lp = (long *)&spcl;
	sum = 0;
	cnt = sizeof(union u_spcl) / (4 * sizeof(long));
	while (--cnt >= 0) {
		sum += *lp++;
		sum += *lp++;
		sum += *lp++;
		sum += *lp++;
	}
	spcl.c_checksum = CHECKSUM - sum;
	writerec((char *)&spcl, 1);
}

struct dinode *
getino(inum)
	ino_t inum;
{
	static daddr_t minino, maxino;
	static struct dinode inoblock[MAXINOPB];

	curino = inum;
	if (inum >= minino && inum < maxino)
		return (&inoblock[inum - minino]);
	bread(fsbtodb(sblock, ino_to_fsba(sblock, inum)), (char *)inoblock,
	    (int)sblock->fs_bsize);
	minino = inum - (inum % INOPB(sblock));
	maxino = minino + INOPB(sblock);
	return (&inoblock[inum - minino]);
}

/*
 * Read a chunk of data from the disk.
 * Try to recover from hard errors by reading in sector sized pieces.
 * Error recovery is attempted at most BREADEMAX times before seeking
 * consent from the operator to continue.
 */
int	breaderrors = 0;		
#define	BREADEMAX 32

void
bread(blkno, buf, size)
	daddr_t blkno;
	char *buf;
	int size;	
{
	int cnt, i;
	extern int errno;

loop:
	if ((int)lseek(diskfd, ((off_t)blkno << dev_bshift), 0) < 0)
		msg("bread: lseek fails\n");
	if ((cnt = read(diskfd, buf, size)) == size)
		return;
	if (blkno + (size / dev_bsize) > fsbtodb(sblock, sblock->fs_size)) {
		/*
		 * Trying to read the final fragment.
		 *
		 * NB - dump only works in TP_BSIZE blocks, hence
		 * rounds `dev_bsize' fragments up to TP_BSIZE pieces.
		 * It should be smarter about not actually trying to
		 * read more than it can get, but for the time being
		 * we punt and scale back the read only when it gets
		 * us into trouble. (mkm 9/25/83)
		 */
		size -= dev_bsize;
		goto loop;
	}
	if (cnt == -1)
		msg("read error from %s: %s: [block %d]: count=%d\n",
			disk, strerror(errno), blkno, size);
	else
		msg("short read error from %s: [block %d]: count=%d, got=%d\n",
			disk, blkno, size, cnt);
	if (++breaderrors > BREADEMAX) {
		msg("More than %d block read errors from %d\n",
			BREADEMAX, disk);
		broadcast("DUMP IS AILING!\n");
		msg("This is an unrecoverable error.\n");
		if (!query("Do you want to attempt to continue?")){
			dumpabort(0);
			/*NOTREACHED*/
		} else
			breaderrors = 0;
	}
	/*
	 * Zero buffer, then try to read each sector of buffer separately.
	 */
	bzero(buf, size);
	for (i = 0; i < size; i += dev_bsize, buf += dev_bsize, blkno++) {
		if ((int)lseek(diskfd, ((off_t)blkno << dev_bshift), 0) < 0)
			msg("bread: lseek2 fails!\n");
		if ((cnt = read(diskfd, buf, (int)dev_bsize)) == dev_bsize)
			continue;
		if (cnt == -1) {
			msg("read error from %s: %s: [sector %d]: count=%d\n",
				disk, strerror(errno), blkno, dev_bsize);
			continue;
		}
		msg("short read error from %s: [sector %d]: count=%d, got=%d\n",
			disk, blkno, dev_bsize, cnt);
	}
}