Re: [PATCH] btrfs-progs: wipe all copies of the stale superblock

[Anand Jain <anand.jain@oracle.com>]

  Ok. Will update the change log.

> A better place for this code is really inside btrfs_wipe_existing_sb.
> Furthermore looking at libblkid it supports a way to wipe multiple
> superblocks by way of: blkid_do_wipe. I.e
> https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.21/libblkid-docs/libblkid-Low-level-tags.html#blkid-do-wipe
> 
> Apparently this functionality has been in libblkid for quite some time
> according to this blog post -
> http://karelzak.blogspot.bg/2011/11/wipefs8-improvements.html (Karel Zak
> is the person mainting various system libraries).
> 
> So can't we at the very least:
> 
> 1) Remove some of our (open coded) implementation of
> btrfs_wipe_existing_sb and use the generic blkid implementation.
> 
> 2) Incorporate your code into btrfs_wipe_existing_sb OR extend the usage
> of the generic blkid_do_wipe to wipe multiple copies of the sb ?

  In btrfs_prepare_device() we have already zeroed the SBs which were
  within the block count. The btrfs_wipe_existing_sb() is to handle the
  other type of FS SBs. Definitely, we can consolidate all this into a
  single function using libblkid. However, it can be done in a separate
  patch.

Thanks, Anand