From: Andreas Gruenbacher Subject: Re: [PATCH v11 21/48] ext4: Add richacl feature flag Date: Mon, 19 Oct 2015 17:34:54 +0200 Message-ID: References: <1445008706-15115-1-git-send-email-agruenba@redhat.com> <1445008706-15115-22-git-send-email-agruenba@redhat.com> <5621346E.5000500@gmail.com> <5624ED40.7040206@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: Alexander Viro , "Theodore Ts'o" , Andreas Dilger , "J. Bruce Fields" , Jeff Layton , Trond Myklebust , Anna Schumaker , Dave Chinner , linux-ext4 , xfs-VZNHf3L845pBDgjK7y7TUQ@public.gmane.org, LKML , linux-fsdevel , Linux NFS Mailing List , linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linux API , "Aneesh Kumar K.V" To: Austin S Hemmelgarn Return-path: In-Reply-To: <5624ED40.7040206-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-ext4.vger.kernel.org On Mon, Oct 19, 2015 at 3:16 PM, Austin S Hemmelgarn wrote: > On 2015-10-16 13:41, Andreas Gruenbacher wrote: >> >> On Fri, Oct 16, 2015 at 7:31 PM, Austin S Hemmelgarn >> wrote: >>> >>> I would like to re-iterate, on both XFS and ext4, I _really_ think this >>> should be a ro_compat flag, and not an incompat one. If a person has the >>> ability to mount the FS (even if it's a read-only mount), then they by >>> definition have read access to the file or partition that the filesystem >>> is contained in, which means that any ACL's stored on the filesystem are >>> functionally irrelevant, >> >> It is unfortunately not safe to make such a file system accessible to >> other users, so the feature is not strictly read-only compatible. >> > OK, seeing as I wasn't particularly clear as to why I object to this in my > other e-mail, let's try this again. > > Can you please explain exactly why it isn't safe to make such a filesystem > accessible to other users? See here: http://www.spinics.net/lists/linux-ext4/msg49541.html Andreas