From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: [topic proposal] dealing with ->d_revalidate() right ways (automounting, atomic opens and the whole mess around that) Date: Wed, 9 Jun 2010 03:19:40 +0100 Message-ID: <20100609021940.GW31073@ZenIV.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org To: lsf10-pc@lists.linuxfoundation.org Return-path: Received: from zeniv.linux.org.uk ([195.92.253.2]:55513 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751548Ab0FICTm (ORCPT ); Tue, 8 Jun 2010 22:19:42 -0400 Content-Disposition: inline Sender: linux-fsdevel-owner@vger.kernel.org List-ID: That's going to be the next big change of VFS architecture; bits and pieces had been discussed on lists and in private mail, but it would be really useful to sit down and discuss that face to face with everyone involved. * ->follow_link() is abused for triggering submounts. * ->d_revalidate() is abused in many, _many_ ways, including autofs, NFS "reval_dot" stuff, atomic opens, etc. Moreover, it has nasty interplay with crossing mountpoints. * NFS handling of atomic opens is near the point where we can switch to methods that would get proper arguments directly, rather than abusing ->lookup/->d_revalidate/whatnot. Again, ->d_revalidate and mountpoint crossing are stumbling blocks. And NFS4 bits around open are just plain scary... * NFSv4 has rather unpleasant stuff in submount handling - what it does with ->mnt_devname doesn't bear describing in polite company and it actually doesn't work right with mount --bind (moderately) and mountinfo contents (completely). Both issues are fixable and that gets entangled into the aforementioned ball of barbed wire... Who might want to be there: nfsd/nfs/cifs/afs/autofs4 and general VFS-interested folks.