On Nov 22, 2008 12:36 +0900, Tetsuo Handa wrote:
> Compressing whole image files includes compressing deleted/unused bytes within
> a block. This means that non-zero bytes in deleted/unused blocks affect
> compression ratio.
>
> static char buffer[4096];
> memset(buffer, 0, sizeof(buffer));
> snprintf(buffer, sizeof(buffer) - 1, "%s/XXXXXX", argc > 1 ? argv[1] : "");
> if ((fd = mkstemp(buffer)) != EOF) {
> unlink(buffer);
> memset(buffer, 255, sizeof(buffer));
> while (write(fd, buffer, sizeof(buffer)) > 0);
Why would you fill the buffer with 0xff instead of 0?
In fact no such program is needed, just "dd if=/dev/zero of=/{fs}/tmp"
and then delete the file.
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
