From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gabriel de Perthuis Subject: Re: [PATCH] Don't register if a non-bcache superblock is found as well Date: Mon, 22 Jul 2013 13:00:20 +0200 Message-ID: <51ED10C4.2050808@gmail.com> References: <1374430637-12954-1-git-send-email-g2p.code@gmail.com> <51ED0BAB.4040604@excellency.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <51ED0BAB.4040604-SxHCd5+OuqTrt3ojHgZu+w@public.gmane.org> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Cyril B." Cc: Kent Overstreet , linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-bcache@vger.kernel.org > Gabriel wrote: >> This should fix it. >> >> Because the raid superblock is at the end of the device, bcache's >> udev rules could detect a bcache device on the unassembled raid >> member. A better fix would be to merge probe-bcache into >> util-linux's blkid. > > 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.