From: Theodore Ts'o Subject: Re: Journal under-reservation bug on first >2G file Date: Wed, 1 Oct 2014 18:43:25 -0400 Message-ID: <20141001224325.GE2903@thunk.org> References: <542B1C38.9010409@redhat.com> <542B1EFC.4050500@redhat.com> <20141001115320.GA2903@thunk.org> <542C1314.3030603@redhat.com> <20141001195954.GD2903@thunk.org> <542C65FD.5040405@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andreas Dilger , ext4 development To: Eric Sandeen Return-path: Received: from imap.thunk.org ([74.207.234.97]:59798 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751612AbaJAWna (ORCPT ); Wed, 1 Oct 2014 18:43:30 -0400 Content-Disposition: inline In-Reply-To: <542C65FD.5040405@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Oct 01, 2014 at 03:37:17PM -0500, Eric Sandeen wrote: > > Ok. I guess this is only an issue for ext4 - well, at least this specific > issue. Delalloc makes it much different than ext2 & ext3, which reserve quite a > lot more. Whether there's a corner case over there which breaks, I dunno... > > So it seems like the simplest test is simply: Are we RW mounted with delalloc? > And if so, update the feature. Seems simpler than mucking with "which features > are unique to ext4" I'd do "are we RW mounted with the extents feature". That way we don't need to worry about someone accidentally mounting a partition meant for Hurd using ext4, which would imply delalloc, and then causing Hurd to no longer be able to deal with the file system. That *shouldn't* happen, but if someone accidentally mounts the file system with -t ext4, but it seems safer to gate it on the existence of the extents feature. - Ted