From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk ([195.92.253.2]:40204 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752644AbdLHANJ (ORCPT ); Thu, 7 Dec 2017 19:13:09 -0500 Date: Fri, 8 Dec 2017 00:13:02 +0000 From: Al Viro Subject: Re: False lockdep completion splats with loop device Message-ID: <20171208001302.GK21978@ZenIV.linux.org.uk> References: <20171205030352.6xdopj7cpy5zlwzv@thunk.org> <20171205150741.xsbp4mtilqfrsukl@thunk.org> <20171205210956.GZ5858@dastard> <20171207235922.GJ5858@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171207235922.GJ5858@dastard> Sender: fstests-owner@vger.kernel.org To: Dave Chinner Cc: Amir Goldstein , Byungchul Park , Theodore Ts'o , fstests , linux-fsdevel , Peter Zijlstra , mingo@redhat.com, kernel-team@lge.com List-ID: On Fri, Dec 08, 2017 at 10:59:22AM +1100, Dave Chinner wrote: > > 3. if multi nested looped fs is important (not really) then loop/nbd will > > need to know if its file is on a looped fs and propagate nesting level > > to ext4 > > This functionality is definitely used and needs to be supported by > the annotations. FWIW, in addition to loop, there's md. So should loop need to know if its backing file lives on a filesystem that does, for example, have an extrnal journal sitting on RAID1 with one of the components hosted in a file on some other fs, brought into the array via another loop device? Oh, and to make life even more fun, backing file can be flipped under configured /dev/loop. IOW, those nesting depths are not static at all.