Hi Matteo, > I'm developing a feature which aligns the file content to the > filesystem boundary by adding a PAX comment header. > This, along with, the --offset option will allow to extract a Debian > package (which is an an archive embedding a tar one), > by using under Linux the FICLONERANGE ioctl(), and extract the archive > without doing any IO.
The idea is interesting. However, I believe that "without doing any IO" is an exaggeration. Indeed, FICLONERANGE allows you to make contents of one file descriptor appear under another file descriptor and that doesn't require additional I/O. But *reading* from that other descriptor would mean I/O activity, as usual. So, it seems that this will have the same effect as running ar p DEBFILE | tar tfJ - (modulo compression option). Am I missing something? Regards, Sergey
