From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Cyril B." Subject: Re: [PATCH] Don't register if a non-bcache superblock is found as well Date: Mon, 22 Jul 2013 16:36:08 +0200 Message-ID: <51ED4358.6030005@excellency.fr> References: <1374430637-12954-1-git-send-email-g2p.code@gmail.com> <51ED0BAB.4040604@excellency.fr> <51ED10C4.2050808@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <51ED10C4.2050808-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Gabriel de Perthuis Cc: Kent Overstreet , linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-bcache@vger.kernel.org Gabriel de Perthuis wrote: >> I'm afraid that doesn't work: with that patch, my backing device doesn't even get registered anymore, since blkid will detect it as XFS: > > I just tried making an xfs filesystem on a bcache device, > and the xfs superblock isn't visible to the backing device. > > Your problem is likely an old superblock; use wipefs before make-bcache. > > If you do find a filesystem that doesn't put its blkid magic > at a fixed offset from the start of the device, we could > consider alternatives, like whitelisting them or porting to blkid. > > For now, better safe than sorry. After zeroing my devices and trying again, I cannot reproduce the issue. I guess you're right, I must have had an old superblock or something. Thanks for the fix. Cyril