From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: How to cope with two incompatible overlayfs formats out in the wild Date: Wed, 19 Nov 2014 01:59:08 +0000 Message-ID: <20141119015908.GV7996@ZenIV.linux.org.uk> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Miklos Szeredi Cc: Andy Whitcroft , Serge Hallyn , Neil Brown , linux-unionfs@vger.kernel.org, Kernel Mailing List , Linus Torvalds List-Id: linux-unionfs@vger.kernel.org On Tue, Nov 18, 2014 at 03:28:03PM +0100, Miklos Szeredi wrote: > So from mainline we need two things: > > - when mounting distinguish between old and new format. > > - userspace can detect which formats are supported by the kernel. > > If we'd have a different filesystem type for the old and new formats, > then that would solve both (checking /proc/filesystems would indicate > which one is supported). > > Unfortunately that would mean having to change "overlayfs" type to > something else in 3.18. Question is, is there some sane name which > would fit? "overlayfs2" is perhaps the best, but I'm not overly > enthusiastic about it. > > Any other ideas? Umm... What does the old one do when it sees workdir= in the options?