[Libguestfs] Should we always do wipefs before mkfs? Discuss ...

[Karel Zak]

On Mon, Feb 04, 2013 at 06:23:38PM +0000, Richard W.M. Jones wrote:
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=907554

 All mkfs.<type> should be robust enough to wipe the device. I'm
 currently working with guys around filesystems to improve mkfs.ext4
 and mkfs.xfs

    https://bugzilla.redhat.com/show_bug.cgi?id=902512

 .. but nothing is perfect so explicitly call wipefs(8) from
 installers or things like libguestfs is definitely good idea.

> We could change libguestfs's guestfs_mkfs (internally) so it always
> does an implicit wipefs on the filesystem.  wipefs is not too onerous --
> in particular I believe it only writes to a few chosen areas of the
> disk.  Especially considering that we're about to run mkfs anyway
> which for some filesystems writes a lot of blocks.

 wipefs(8) (or blkid_do_wipe() from the library) wipes only magic
 strings to make the filesystem (raids or partition tables) invisible
 for libblkid. It means very few bytes.

> Thoughts?

 Go ahead :-)

    Karel


-- 
 Karel Zak  <kzak at redhat.com>
 http://karelzak.blogspot.com