From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vivek Goyal Subject: Re: [PATCH 5/7] ovl: Set OVL_METACOPY flag during ovl_lookup() Date: Fri, 6 Oct 2017 11:15:22 -0400 Message-ID: <20171006151522.GB10750@redhat.com> References: <1506951605-31440-1-git-send-email-vgoyal@redhat.com> <1506951605-31440-6-git-send-email-vgoyal@redhat.com> <20171003152742.GF14308@redhat.com> <20171003182026.GG14308@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx1.redhat.com ([209.132.183.28]:57862 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751487AbdJFPPX (ORCPT ); Fri, 6 Oct 2017 11:15:23 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-unionfs-owner@vger.kernel.org List-Id: linux-unionfs@vger.kernel.org To: Amir Goldstein Cc: overlayfs , Miklos Szeredi On Wed, Oct 04, 2017 at 10:48:36AM +0300, Amir Goldstein wrote: [..] > > Ok. Before I dive into details of that patch, I have a concern about > > creating index of all regular files and verifying them on mount time. Will > > this lead to excessive mount time overhead for a large index. I mean > > in container land, people do mount/unmount of container roots very > > frequently. And paying this verification cost on every mount, can soon > > start showing up and become a concern. > > Vivek, > > That is a valid concern. > Counter proposal: > > Have metacopy depend on index=on but not index every regular file. > > This way you still get the assurance that you cannot set inconsistent > origins to 2 broken hardlinks of the same origin, which would break > future mount with index=on. > > So counter to what I wrote earlier, has_upper_alias AND !index will > be a valid state. > If you find in lookup an upper with METACOPY and no/stale origin > you return ESTALE. Ok, I will post V2 patches and return -ESTALE if metacopy xattr is present but origin could not be found/resolved during lookup. Vivek