Function skip_matched

fileio.c:192–212

An in-place update found identical data at an identical location. We either * just seek past it, or (for an in-place sparse update), we give the data to * the sparse processor with the use_seek flag set. */

 * just seek past it, or (for an in-place sparse update), we give the data to
 * the sparse processor with the use_seek flag set. */
int skip_matched(int fd, OFF_T offset, const char *buf, int len)
{
	OFF_T pos;

	if (sparse_files > 0) {
		if (write_file(fd, 1, offset, buf, len) != len)
			return -1;
		return 0;
	}

	if (flush_write_file(fd) < 0)
		return -1;

	if ((pos = do_lseek(fd, len, SEEK_CUR)) != offset + len) {
		rsyserr(FERROR_XFER, errno, "lseek returned %s, not %s",
			big_num(pos), big_num(offset));
		return -1;
	}

	return 0;
}

/* This provides functionality somewhat similar to mmap() but using read().
 * It gives sliding window access to a file.  mmap() is not used because of